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  • 1995-1999  (1.073)
  • 1996  (1.073)
  • Engineering  (847)
  • Analytical Chemistry and Spectroscopy  (226)
  • Nuclear reactions
  • 1
    Digitale Medien
    Digitale Medien
    Computation of 3-D electromagnetic field using differential forms based elements and dual formulations (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 81-98 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The vector and scalar variables describing electromagnetic fields with different requirements of continuity can be identified to four different degrees of differential forms. The association of differential forms with finite elements leads to a set of differential forms based elements (Whitney elements); they are naturally adapted to the discretization of different vector and scalar variables. With the help of a Tonti diagram, Maxwell equations can be classified by two dual sequences together with the constitutive laws of materials. The application of Whitney elements to the two dual sequences leads to two dual approximation schemes. As an example, two dual formulations for eddy current computation using potential variables and the hybrid finite element - boundary element method are derived, where Whitney 3-D and 2-D elements are employed. A numerical application is given at the end of the paper, where the dual features of the two formulations are reported.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Finite element iterative solution of skin effect problems in open boundaries (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 125-143 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The paper proposes an iterative procedure, called current iteration, for the finite element solution of two-dimensional steady-state skin effect problems in open boundaries. In the procedure a fictitious boundary is introduced enclosing all the conductors. On it, the magnetic vector potential is first guessed and then iteratively updated according to the current density computed in the conductors. Conditions are obtained implying convergence to the exact solution of the unbounded problem whatever the initial guess. The choice of the fictitious boundary and the selection of the relaxation parameter in such a way that computational efficiency is obtained are discussed. The greatest advantage of the procedure is its ease of implementation in a pre-existing finite element code for bounded problems. An axisymmetric version of the procedure is also described since implementation only involves minor changes as compared with the 2-D one. Examples are provided in order to clarify and validate the procedure and compare it with other techniques.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    AN FFT-BASED FORMULATION FOR THE COMPUTATION OF ELECTROMAGNETIC SCATTERING FROM 3-D, PERFECTLY CONDUCTING BODIES (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 225-236 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: An FFT-based formulation for the computation of electromagnetic scattering from 3-D, perfectly conducting objects is presented. The formulation solves the EFIE iteratively via a conjugate gradient scheme and has the major advantage of a low storage requirement for scatterers in the resonance region. This factor, coupled with the low run-times resulting from use of the FFT to compute the associated matrices, makes the formulation a particularly efficient one. Numerical results encompassing current distributions and far-field radar cross-sections are presented for PEC cubes of resonant size. It is shown that the computed results yield good agreement compared with other numerical techniques and experimental data.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    THREE-DIMENSIONAL FULL-VECTOR ANALYSIS OF OPTICAL WAVEGUIDES BY FINITE-INTEGRATION BEAM-PROPAGATION METHOD (FIBPM) (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 249-258 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: In the paper a novel finite-integration beam-propagation method (FIBPM) is presented. This method is especially suited for the simulation of optical waveguides containing extremely thin layers of complex permittivity. For calculating the propagating optical field an efficient algorithm based on expansion of the matrix exponential in Chebyshev polynomials is applied. The derivation of the propagation algorithm is given, also detailing the convergence criteria. A code for a massively parallel computer has been developed and applied successfully to complex waveguide structures used for high-power laser diodes
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Report. Final report on the First International Workshop on Transmission Line Matrix (TLM) Modeling  -  Theory and Applications (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 167-170 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: No Abstract
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    A MODIFIED FINITE DIFFERENCE METHOD FOR MODELLING DIFFUSION PROCESSES (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 215-223 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A time domain unconditionally stable explicit method is presented which may be used to model processes governed by the diffusion equation such as transient heat flow. Unlike the explicit finite difference routine, the method models the diffusion process within the time step (MPWT). Being explicit, the method (MPWT) may easily account for non-linear physical parmeters and may be compared with the transmission line matrix (TLM) method of diffusion modelling in terms of its utility. Unlike the TLM model, however, the equivalent circuit does not contain inductive components which have no clear physical meaning. The MPWT method is based on a simple resistive and capacitive circuit model, which for short time steps reduces to the explicit finite difference formulation but is stable for large time steps. Good agreement has been found when results obtained using this algorithm are compared with other numerical methods and analytical results.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    TENSOR-AIDED GEARBOX MODELLING (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 181-190 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: This paper develops an electrical analogue for a gearbox suitable for use in the time-domain modelling of many electromechanical systems, with tensor methods being used to define the changing conditions in the gearbox brought about by backlash. Unlike most existing models it is compatible with the time-varying and discontinuous models often used to describe the electrical items of a typical system, and it allows for the effects of these items of mechanical non-linearities and discontinuities such as friction and backlash.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    A METHOD FOR INCORPORATING CHARGED PARTICLE MOTION WITHIN A 2-D TLM FIELD CODE (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 201-214 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Charged particle motion is incorporated within a transmission line modelling (TLM) field code to establish a new model which allows the investigation of field-particle interactions. The model is validated by using it to predict the trajectory of moving particles and the field and potential distributions inside a planar diode for which analytical solutions are available. The effect of space charge on the operation of the diode is also investigated. The model is then applied to study in detail a practical electron gun design.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Masthead (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996) 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jnm.1660090301
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  • 10
    Digitale Medien
    Digitale Medien
    Neuromagnetic field computation using the multiple multipole method (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 145-158 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: For the interpretation of human neuromagnetic data it is necessary to compute the magnetic field of a source (e.g. a dipole) in a volume conductor (e.g. a homogeneous conducting sphere or a homogeneous head model). The Multiple Multipole (MMP) method, which is a semianalytical field calculation method, is applied to neuromagnetic field calculation for the first time. The unique feature of the MMP method is that multipole expansions are used for the description of the electromagnetic field. First a validation of the MMP method is done with the help of a spherical model and an analytical solution. Then the MMP method is applied to a realistically shaped one compartment head model. The results are compared to results obtained with the Boundary Element Method (BEM). The results suggest that it is possible to solve the neuromagnetic forward problem faster with the help of the MMP method than with the conventional numerical field calculation methods for realistic shaped volume conductor models. Further investigations are necessary to tackle the inverse problem of biomagnetism with the MMP method.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    FAST S-PARAMETER COMPUTATION OF A MICROSTRIP INTERDIGITAL FILTER USING TLM, PRONY'S AND DIGITAL FILTERING TECHNIQUES (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 237-248 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A spectral estimation technique based on Prony's method has been used to analyse a five section microstrip interdigital filter with the TLM method. The time response of the filter is expressed as the sum of only five damped sinusoids, yielding an analytical expression for the time response. Furthermore, since an analytical Fourier transform exists for this expression, the frequency response is obtained without applying the fast Fourier or discrete Fourier transform. This typically reduces the time required for a TLM analysis by a factor of five. The approximation agrees very well with a full TLM time response. It is also shown that the numerical noise due to single precision computation of the absorbing boundary algorithm can be eliminated by digital filtering techniques. The effect of the via holes used for grounding the quarter-wave resonators of the filter has been included by discretizing them along with the rest of the circuit. Scattering parameters for the filter compare well with measurements published by Swanson.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    DISCRETE SIMULATION OF UNIFORM TRANSMISSION LINES BY MULTIDIMENSIONAL DIGITAL FILTERS (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 271-294 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Recently, a new method has been presented for the discrete simulation of multidimensional systems, which are described by linear partial differential equations with constant coefficients. It is based on methods customary in linear systems theory and digital signal processing and uses a frequency-domain representation of the continuous system to be simulated. A proper choice of functional transformations for each independent variable allows us to treat the influence of initial conditions, boundary conditions and excitation functions separately by suitable transfer functions. From these, corresponding discrete transfer functions and the structure of a discrete system for the simulation of the continuous problem are derived. The application of this method to wave propagation problems on uniform transmission lines is presented here. At first, the continuous problem is characterized by transfer functions; then the derivation of a discrete system is shown, and finally, some simulation results and a comparison with other methods are given.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Forthcoming papers (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 325-325 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jnm.1660090402
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  • 14
    Digitale Medien
    Digitale Medien
    OPTIMIZATION ISSUES IN FINITE ELEMENT CODES FOR SOLVING OPEN DOMAIN 3D ELECTROMAGNETIC SCATTERING AND CONFORMAL ANTENNA PROBLEMS (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 335-344 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The first part of the paper presents the implementation and performance of a new absorbing boundary condition (ABC) for truncating finite element meshes. This ABC can be applied conformally to the surface of the structure for scattering and antenna radiation calculations. Consequently, the computational domain is reduced dramatically, thus allowing the simulation of much larger structures, and results are presented for three-dimensional bodies. The latter part of the paper discusses optimization issues relating to the solver's CPU speed on parallel and vector processors. It is shown that a jagged diagonal storage scheme leads to a four-fold increase in the FLOP rate of the code, and a standard matrix profile reduction algorithm substantially reduces the inter-processor communication.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Masthead (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996) 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jnm.1660090501
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  • 16
    Digitale Medien
    Digitale Medien
    A COMBINED FINE-COARSE MESH METHOD FOR THE TRANSMISSION LINE MODELLING OF DIFFUSION (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 405-415 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: An improved combined fine-coarse mesh (CFCM) method for two transmission line models of diffusion is described. The method allows regular cells of different sizes to be connected and solved simultaneously. The CFCM method is applied to (a) a finite difference algorithm, (b) a conventional transmission line model and (c) a lossy transmission line model. The latter model is shown to be the most accurate. The proposed CFCM method is also compared with the graded mesh and the multigrid techniques.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    DISCRETE MODELS OF HEAT FLOW IN LAYERED MATERIALS USING SIMPLE AND CORRELATED RANDOM WALKS (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 445-457 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The paper reviews some discrete probabilistic numerical techniques with particular emphasis on heat flow in inhomogeneous materials. The effects of different nodal configurations on the development of suitable algorithms are outlined and we suggest a new and consistent description for the discrete apparent effusivity. Our approach is then discussed in the context of TLM, and analogues are presented for flux relaxation time and effusivity.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    LETTER TO THE EDITOR. A GENERAL EXPRESSION OF BOUNDARY CONDITIONS IN TLM DIFFUSION MODELLING (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 459-461 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: We show that the general boundary condition D∂Φ/∂x + αΦ = 0 (D is the diffusion coefficient and α is a constant) in TLM diffusion modelling can be expressed accurately in terms of a voltage reflection coefficient ρ = (Δx - αΔt)/(Δx + αΔt), where Δx is the spatial resolution and Δt is the time step. Based on this general expression, the special cases of short-circuit (ρ = -1), open-circuit (ρ = 1) and matched-load (ρ = 0) boundaries can be described succinctly by α → ∞, α → 0 and α = Δx/Δt, respectively. This formulation allows for straightforward treatment of mixed boundary conditions found, for example, in diffusion-drift systems.
    Zusätzliches Material: 1 Ill.
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  • 19
    Digitale Medien
    Digitale Medien
    Synthesis, inverse problems and optimization in computational electromagnetics (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 45-57 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The paper gives an overview on mathematical optimization techniques specially suited to problems in electromagnetism. It is described how efficient optimization procedures consist of decision making, treatment of non-linear constraints, and an algorithm for minimizing the objective function. The optimization of a rectangular waveguide branching, a permanent magnet synchronous machine, and the iron cross-section of a superconducting magnet are given as examples. Optimization routines are used for the tracing of manufacturing errors in the production of superconducting coils. Finally the application of a genetic algorithm to a dipole coil design is discussed as an example for field synthesis.
    Zusätzliches Material: 6 Ill.
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  • 20
    Digitale Medien
    Digitale Medien
    Numerical differentiation in magnetic field postprocessing (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 99-113 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Postprocessing encompasses graphic display and numerical computation. The critical process in this work is numerical differentiation. Methods of numerical differentiation of approximate solutions may be divided into three groups: direct numerical differentiation, smoothing methods based on superconvergence properties, and methods that exploit properties the solution is known to possess though the numerical approximation does not. The choice of method is determined by the problem, as well as the use to which derivatives are put: graphical display, local field calculation, mesh refinement or a a posteriori error estimation. The paper compares current derivative extraction methods and reviews progress in this field, with particular attention to superconvergent patch recovery and methods based on Green's second identity. A new modification of the method based on Green's second identity is presented, to include inhomogeneous and discontinuous materials.
    Zusätzliches Material: 3 Ill.
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  • 21
    Digitale Medien
    Digitale Medien
    Verification of computational electromagnetic programs (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 159-165 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Although software testing comprises a large body of knowledge and is extensively used in verification and validation (V&V) of software and software systems, the need to verify engineering software posses unique challenges. Electromagnetic programs fall under the category of so-called non-testable programs, a group that includes numerical computation and most other programs that use floating point operations. There are, however, certain techniques that can be used to check for program correctness in the context of expected behaviour and results. The approach to testing by multiple methods, multiple codes and multiple algorithms is well known as an effective tool in testing of scientific software. In addition, testing against canonical and known solutions, evaluation of programs based on properties of the computation performed and error analysis are all common techniques used to verify computer programs. Their use in the context of the TEAM series of problems and workshop is used as an example for a unique method of verification of programs and to underscore the needs of both users and program developers in this important issue of code validation.
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  • 22
    Digitale Medien
    Digitale Medien
    EFFICIENT STABILITY ANALYSIS OF FREE RUNNING MICROWAVE OSCILLATORS IN THE FREQUENCY DOMAIN (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 171-179 
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    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A stability analysis of free running oscillators in the frequency domain is presented. By insertion of a simple damping subnetwork, depending on one parameter, a global stability analysis starting in a Hopf bifurcation is performed. Near the bifurcation, stability of a periodic orbit is determined by studying stability of the stationary solutions. Provided turning and bifurcation points are detected, stability is thus known on the whole path connecting the Hopf bifurcation and the solution of the undamped oscillator network. It is shown that for the generation of starting values for the signal analysis by homotopy and for the stability analysis the same solution path can be utilized. Thus coupling of large-signal and stability analysis leads to an efficient algorithm where stability of oscillatory solutions is computed as a by-product of signal analysis with hardly any additional cost. The presented method is applied to a microwave oscillator at 15 GHz and to an oscillator model which has several coexisting large-signal solutions. Our method may be combined with any large-signal analysis program based on a piecewise network description. It may be fully automated and requires no sophisticated knowledge of the program user about stability analysis or bifurcation theory.
    Zusätzliches Material: 7 Ill.
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  • 23
    Digitale Medien
    Digitale Medien
    Forthcoming papers (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. ii 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jnm.1660090302
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  • 24
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    Digitale Medien
    TRANSIENT ANALYSIS OF n-TIER GaAs MESFET MATRIX AMPLIFIERS BY THE TLM METHOD (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 259-270 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The performances of n-tier GaAs MESFET matrix amplifiers are studied in the time domain. The model is developed incorporating the parasitic resistive loss and internal coupling capacitance of the active device. Techniques are contemplated to transform the matrix amplifier into a set of coupled multi-conductor transmission lines. The resultant model is analysed by the TLM method. Impulse responses of 2 × 4 and 3 × 3 matrix amplifiers are investigated. The frequency responses of the amplifiers are obtained through a Fourier transform. Agreement is observed between results obtained by the TLM model and those obtained by other analytical methods or a complicated circuit analysis program. A 5 × 7 matrix amplifier is also analysed to show the advantage of the developed method.
    Zusätzliches Material: 11 Ill.
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  • 25
    Digitale Medien
    Digitale Medien
    CAN THE TRANSMISSION LINE MATRIX METHOD YIELD STATIONARY SOLUTIONS OF THE TIME-DEPENDENT SCHRÖDINGER EQUATION? (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 321-323 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: By virtue of the success of the transmission line matrix method (TLM) in solving heat and matter diffusion problems, it should also be applicable to the time-dependent Schrödinger equation. The occurrence of complex-valued circuit elements does notdestroy the unconditional stability of the routine. But it seems to be impossible to obtain stationary (eigen)solutions to this equation as well as separable solutions to the diffusion equation. It is suggested that this is due to the non-dissipativity of the TLM routine.
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  • 26
    Digitale Medien
    Digitale Medien
    TIME DOMAIN ELECTROMAGNETIC FIELD COMPUTATION WITH FINITE DIFFERENCE METHODS (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 295-319 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The solution of Maxwell's equations in the time domain has now been in use for almost three decades and has had great success in many different applications. The main attraction of the time domain approach, originating in a paper by Yee (1966), is its simplicity. Compared with conventional frequency domain methods it takes only marginal effort to write a computer code for solving a simple scattering problem. However, when applying the time domain approach in a general way to arbitrarily complex problems, many seemingly simple additional problems add up. We describe a theoretical framework for solving Maxwell's equations in integral form, resulting in a set of matrix equations, each of which is the discrete analogue to one of the original Maxwell equations. This approach is called Finite Integration Theory and was first developed for frequency domain problems starting about two decades ago. The key point in this formulation is that it can be applied to static, harmonic and time dependent fields, mainly because it is nothing but a computer-compatible reformulation of Maxwell's equations in integral form. When specialised to time domain fields, the method actualy contains Yee's algorithm as a subset. Further additions include lossy materials and fields of moving charges, even including fully relativistic analysis.For amny practical problems the pure time domain algorithm is not sufficient. For instance a waveguide transition analysis requires knowledge of the incoming and outgoing mode patterns for proper excitation in the time domain. This is a typical example where both frequency and time domian analysis are essential and only the combinatin yields the successful result. Typical engineers may wonder why at all one should apply time domain analysis to basically monochromatic field problems. The answer is simple: it is much faster, needs less computer memory, is more general nad typically more accurate. Speed-up factors of over 200 have been reached for realistic problems in filter and waveguide design. The small core space requirement makes time domain methods applicable on desktop computers using milions of cells, and six unknowns per cell - a dimension that has not yet been reached by frequency domain approaches. This enormous amount of mesh cells is absolutely neceesary when complex structures or structures with spacial dimensions of many wavelengths are to be studied. Our personal recod so far is a waveguide problem in which we used 72,000,000 unknowns.
    Zusätzliches Material: 15 Ill.
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  • 27
    Digitale Medien
    Digitale Medien
    Masthead (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996) 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jnm.1660090401
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  • 28
    Digitale Medien
    Digitale Medien
    TLM TREATMENT OF A GENERAL DIFFUSION FLUX BOUNDARY CONDITION (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 327-333 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: An approach of using a current-controlled voltage source analogy to account for a general boundary condition of particle or thermal flux in transmission-line matrix (TLM) diffusion modelling has been developed. For mass diffusion, this boundary condition is expressed as D ∂C/∂x + αC = 0, where C is the concentration, D is the diffusion coefficient, and α is a parameter characterizing the out-diffusion mobility across the boundary of interest. Confirmation of the TLM numerical treatment through comparison with analytical solutions is presented. Besides the open-circuit and short-circuit boundaries, the matched-load boundary is also found to be a special case of the present boundary condition. This extension of the boundary treatment allows the highly flexible TLM method to be applied to a greater variety of diffusion problems.
    Zusätzliches Material: 5 Ill.
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  • 29
    Digitale Medien
    Digitale Medien
    Forthcoming papers (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 395-395 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jnm.1660090502
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  • 30
    Digitale Medien
    Digitale Medien
    CORRECT MACROMODELLING OF THE COMMON MODE AND POWER SUPPLY REJECTIONS OF OPERATIONAL AMPLIFIERS (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 397-404 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The relationship between common mode rejection and positive and negative power supply rejections of operational amplifiers is derived and compared with symmetrical power supply rejection. The results are used to develop a macromodel which provides a correct representation of the terminal voltages at the op amp pins. The performance of the new macromodel is illustrated comparing simulation results with those of the device level model for the standard integrated circuit op amp uA741.
    Zusätzliches Material: 7 Ill.
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  • 31
    Digitale Medien
    Digitale Medien
    A TLM MODEL OF TRANSIENT, 2-DIMENSIONAL STRESS PROPAGATION (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 429-443 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A TLM nodal structure suitable for modelling the propagation of transient stresses is described. The nodal structure is analysed algebraically using the analogy between TLM and discrete state space control theory. A numerical implementation based on this nodal structure is validated by comparing results generated using the TLM model with those produced using the finite difference approach for the case of pressure applied to a semi-infinite plate.
    Zusätzliches Material: 7 Ill.
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  • 32
    Digitale Medien
    Digitale Medien
    Masthead (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996) 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jnm.1660090601
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  • 33
    Digitale Medien
    Digitale Medien
    Integral equations in electromagnetics (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 3-17 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Algorithms for the numerical solution of continuum electromagnetic field problems are based either on differential or integral formulations. The most common approach, at least for low frequency problems, has been the former, using the finite element method. The paper examines the special advantages of integral equations over differential equations, explores some of the difficulties involved and suggests that, in the context of more advanced problems, i.e. optimization and moving systems, the integral equation approach may be particularly effective.
    Zusätzliches Material: 9 Ill.
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  • 34
    Digitale Medien
    Digitale Medien
    Edge elements for magnetostatics (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 19-34 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Edge-elements are introduced and discussed in the context of complementarity, a desirable characteristic of numerical methods, by which solutions which are equally satisfactory as regards both fields b and h are obtained. By making the vector potential approach easier than with standard nodal elements, edge-elements enhance complementarity. Comparative merits of both kinds of elements are discussed.
    Zusätzliches Material: 9 Ill.
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  • 35
    Digitale Medien
    Digitale Medien
    Automated design and optimization of electromechanical actuators (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 59-69 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The paper investigates various optimization techniques and their suitability for the magnetic design of electromechanical actuators. Selected algorithms, including Gauss-Newton, Levenberg-Marquardt and Trust region, are examined and compared using 18 test functions. The Levenberg-Marquardt method is chosen for its robustness and fast convergence, and incorporated into an automated CAD optimization system (EAMON), which interfaces an external optimizer to a general purpose finite element package. The EAMON program, which is user friendly with pull-down menus, searches for constrained shape design variables that fulfil prescribed performance criteria. The electromagnetic field analysis forms part of the optimization iterative cycle. Finally, two application examples are described. First, a DC solenoid actuator with truncated cone pole face is optimized to produce a user specified force-displacement characteristic. Secondly, an actuator solenoid is optimized to produce maximum energy per stroke.
    Zusätzliches Material: 9 Ill.
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  • 36
    Digitale Medien
    Digitale Medien
    Adaptive methods in computational magnetics (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 71-80 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A review of adaptive methods in 2-D and 3-D for the efficient solution of electromagnetic problems with the finite element method, developed by the authors, is presented in the paper. The adaptive methods presented consist mainly of two processes: mesh refinement and error estimation. A highly efficient technique for the refinement of arbitrary unstructured triangular and tetrahedral meshes, based on Delaunay triangulation, directly applicable and suitable in an automatic adaptive procedure, is described. The use of various error estimation criteria for electromagnetic problems is presented. The implementation of an automatic adaptive procedure with the finite element method, incorporating the above techniques, is provided and applied to the efficient solution of various 2-D and 3-D electromagnetic field problems.
    Zusätzliches Material: 11 Ill.
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  • 37
    Digitale Medien
    Digitale Medien
    Pushing the limits of 2-D boundary element eddy current codes - connectivity (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 115-124 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The serious electromechanical designer is faced with optimizing the shape of a device for a number of conflicting criteria. If the design involves eddy currents with saturable media, a true optimization will take a long time, since it requires a lot of information as input with multiple variable variations. If the analyses must be performed in three dimensions, an inordinate amount of computer time is required even for the simplest of problems. No small advantage is accrued if the problem can be approached in two dimensions. The paper outlines a technique for examining eddy currents induced in complex series wound coils for which the connections must be specified to ensure solution accuracy. A boundary element formulation is adopted in which an arbitrary constant vector potential is assigned to each conductor. The connection of the coils can be specified by placing additional constraints on these vector potentials. The technique is tested against two experiments involving forces imposed on flux eliminating coils.
    Zusätzliches Material: 12 Ill.
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  • 38
    Digitale Medien
    Digitale Medien
    Masthead (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996) 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jnm.1660090101
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  • 39
    Digitale Medien
    Digitale Medien
    HORIZONTAL WIRE ANTENNA ABOVE LOSSY HALF-SPACE: SIMPLE ACCURATE IMAGE SOLUTION (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 191-199 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A simple, approximate, but highly accurate, method is proposed for the analysis of horizontal thin-wire antennas above a lossy half-space. In the first step, the contribution of the lossy half-space to the field of a horizontal Hertzian dipole above the interface, both in the half-space above and in that below the interface, is approximated by the field of few (typically six) equivalent sources (images). The relative image intensities are obtained by enforcing the boundary conditions for the tangential components of the electric and magnetic field at a number of points at the interface. The field of the images is introduced into the Hallén equation; current distribution is approximated by polynomials and determined by point-matching. The results for the impedance of horizontal dipoles obtained by the present method are in excellent agreement with the exact results (obtained from the Sommerfeld theory), although the proposed method is conceptually much simpler and requires at least an order of magnitude less computing time than the exact method.
    Zusätzliches Material: 8 Ill.
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  • 40
    Digitale Medien
    Digitale Medien
    BOOK REVIEW. GENETIC ALGORITHMS IN ENGINEERING AND COMPUTER SCIENCE, edited by G. Winter, J. Péiaux, M. Galán and P. Cuesta, Wiley, Chichester, 1995. ISBN 0-471-95859-X. No of pages: 464. Price: £45.00 (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 324-324 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: No Abstract
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  • 41
    Digitale Medien
    Digitale Medien
    FAST SIMULATION OF MICROSTRIP STRUCTURES USING THE FAST MULTIPOLE METHOD (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 345-357 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: We apply a new method of reducing the computational effort required for solution of the Electric Field Integral Equation used for modelling microstrip structures. The Fast Multipole Method is used to compute the radiation pattern and input impedance of single layer microstrip antennas.
    Zusätzliches Material: 9 Ill.
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  • 42
    Digitale Medien
    Digitale Medien
    A CONSISTENT SUBGRIDDING SCHEME FOR THE FINITE DIFFERENCE TIME DOMAIN METHOD (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 359-374 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Recently, the simulation of high frequency devices has become of increasing importance due to the demand for faster development processes. The Finite Difference Time Domain (FDTD) method has been proved to be an efficient tool for the simulation of electromagnetic phenomena. In the paper we derive a new consistent three-dimensional subgridding scheme for the Finite Integration Technique. In the time domain the latter method reduces to FDTD when only cubical cells are used. The subgridding extension can help to achieve accurate models of small structure details without heavily decreasing numerical efficiency while the properties of continuous Maxwell equations are still conserved in the grid space. After studying numerical dispersion and stability, the applicability of the method is demonstrated by regarding an example studying scattering at a small post in a rectangular waveguide.
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  • 43
    Digitale Medien
    Digitale Medien
    NEW INTEGRATED SIMULATION TECHNIQUES FOR THE ELECTROMAGNETIC ANALYSIS OF MICROWAVE CIRCUITS USING THE TLM METHOD (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 375-393 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A new methodology is presented which allows the integration of lumped elements into electromagnetic simulations, using the TLM method. It is shown that the new method retains the symmetrical condensed node algorithm structure, with the potential to be applied to all lumped elements. A new and accurate method for the extraction of circuit parameters from the impulse response of the TLM method is also presented. The method is simple and can be used for waveguide and planar structures. A study is carried out on the applications of various data windowing techniques during the postprocessing stages of an electromagnetic analysis. This has resulted in the realization of the need for careful selection of a particular window profile, according to the application and the nature of the required results.
    Zusätzliches Material: 21 Ill.
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  • 44
    Digitale Medien
    Digitale Medien
    AUTOMATIC TIME STEP CONTROL IN TLM DIFFUSION MODELLING FOR PROBLEMS WITH TIME-VARYING LOAD CONDITIONS (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 417-428 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Existing methods for time step control in TLM diffusion modelling that are based on the ‘m’ parameter introduced by Pulko are shown to be inappropriate for problems where the load conditions are arbitrarily time-varying. A new parameter is proposed for monitoring the error in the TLM diffusion model arising from the hyperbolic component of the lossy wave equation. This parameter is used as the controlling variable in a general purpose time step control algorithm and its suitability is demonstrated by applying this algorithm to a number of test cases in which the load conditions are time-varying.
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  • 45
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    Digitale Medien
    BOOK REVIEW. MICROWAVE AND OPTICAL WAVEGUIDE ANALYSIS BY THE FINITE ELEMENT METHOD by F. Anibal Fernandez and Yilong Lu, Research Studies Press, ISBN 0-86380-182-X, 1996, 205 pp, $40.00. (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 462-462 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: No Abstract
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  • 46
    Digitale Medien
    Digitale Medien
    Editorial: Special issue of International Journal of Numerical Modelling: Electronic Networks, Devices and Fields on Computational Magnetics (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 1-1 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: No Abstract
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  • 47
    Digitale Medien
    Digitale Medien
    Knowledge-based and numerical optimization techniques for the design of electromagnetic devices (1996)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 9 (1996), S. 35-44 
    Details
    ISSN: 0894-3370
    Schlagwort(e): Engineering ; Electrical and Electronics Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Automatic electromagnetic device design is now becoming possible. Advances in numerical methods, knowledge-based techniques and database structures are helping to solve the problem of synthesis. The paper discusses the major problems of design and reviews techniques which have been developed for solving them. An architecture for a design system is proposed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    A water trap for static cryo-headspace gas chromatography (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 37-42 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The headspace gas in static headspace gas chromatography contains mostly saturated water vapor. In the case of the cryofocusing enrichment technique this may cause baseline distortion in the early part of the chromatogram or may even lead to ice-plugging of the capillary column. A water-trap is described in which the water vapor is removed from the headspace gas before entering the cryo-trap. The water trap is packed with lithium chloride on a porous support and is regenerated after each analysis by heating under backflush conditions. It therefore can be used for automatic operation. Data are given for the precision and accuracy, and some practical examples, for environmental and flavor analysis are shown.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190107
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  • 49
    Digitale Medien
    Digitale Medien
    Retention of alcohols in steam chromatography using CaCl2—H2O salt as stationary phase (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 59-61 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Steam chromatography ; Salt-water stationary phases ; Retention of alcohols ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190111
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  • 50
    Digitale Medien
    Digitale Medien
    Editorial (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. iii 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190202
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  • 51
    Digitale Medien
    Digitale Medien
    Masthead (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996) 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190101
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  • 52
    Digitale Medien
    Digitale Medien
    Testing the polarity and adsorptivity of nondeactivated GC capillary surfaces (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 27-31 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Test for fused silica surfaces ; Polarity of fused silica surfaces ; Adsorptivity of fused silica surfaces ; Leaching of fused silica ; Stability of fused silica precolumns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Split injection of 1-pentanol headspace on to raw or treated fused silica tubing yields information on the characteristics of its surface (silanol concentration, polarity, adsorptivity). Fused silica tubing from three sources was compared. The effect of various leaching and etching procedures used for column preparation was studied, as was the stability of uncoated fused silica precolumns towards water and some organic solvents.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190105
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  • 53
    Digitale Medien
    Digitale Medien
    A new look at light hydrocarbon separations on commercial alumina PLOT columns: Column selectivity and separation (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 32-36 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Alumina PLOT column ; Column selectivity ; Hydrocarbon gases ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Alumina-coated porous layer open tubular (PLOT) columns are widely used for analyses of light hydrocarbons (C1 to C6). There is, however, a need for improved selectivity for complex analyses such as the determination of impurities in high purity petrochemical products. Some commercial alumina PLOT columns do not have sufficient selectivity for such analyses. The selectivity of four commercial alumina PLOT columns is evaluated for analyses of propylene and ethylene, and differences in column selectivity discussed. Requirements of column selectivity and retention are presented for several applications including the analysis of refinery gas, transformer oil gas, and fuel gas.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190106
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  • 54
    Digitale Medien
    Digitale Medien
    Dimethylbenzothiophenes and methyldibenzothiophenes in crude oils from different sourcesPolycyclic Aromatic Sulfur Heterocycles, V. (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 49-53 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Polycyclic aromatic sulfur heterocycles ; Crude oil ; Oil maturity ; Fingerprinting ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A method is presented for the identification and quantification of C2-substituted benzothiophenes in crude oil. The method will enable analysis of the pattern of these compounds, for example as a basis for differentiating crude oils from one another (fingerprinting) and for investigation of their suitability as indicators of oil maturity. Here results are reported for five crudes from Iraq, Venezuela, Saudi Arabia, the former Soviet Union, and the North Sea. The aromatic fraction of the crudes was oxidized and the dioxides of the heterocycles separated according to the number of carbon atoms in the side chains. The final separation was by capillary GC with atomic emission or flame ionization detection. A fluorinated analog was synthesized and used as internal standard. The concentrations of 2,3-, 2,4-, 2,7-, and 3,7-dimethylbenzothiophene ranged between 11 and 272 ppm. Three other dimethylated benzothiophenes present in lower amounts were also identified.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190109
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  • 55
    Digitale Medien
    Digitale Medien
    Capillary zone electrophoretic separation of isomeric benzoic acids using cyclodextrin (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 143-150 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Capillary zone electrophoresis ; Cyclodextrin ; Aromatic carboxylic acids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A method using capillary zone electrophoresis has been developed for separation of a series of isomeric benzene polycarboxylic acids. The separation was found to depend largely on the geometry of the acids and their degree of ionization as well as on the buffer pH and composition. The presence of additives to the buffer such as cyclodextrin and cationic surfactants was found necessary for complete resolution of all the isomers.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190305
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  • 56
    Digitale Medien
    Digitale Medien
    A new method for the chiral HRGC assay of L-2-hydroxyglutaric acid in urine (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 161-164 
    Details
    ISSN: 0935-6304
    Schlagwort(e): L-2-Hydroxyglutaric acid ; L-2-Hydroxyglutaric aciduria ; Chiral HRGC ; Chiral liquid phases ; Cyclodextrins ; 1(R)-trans-N-N'-1,2-cyclohexenylbisbenzamideoligosiloxane ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: L-2-Hydroxyglutaric aciduria is a recently discovered inherited neurometabolic disease for which diagnostic identification of the right enantiomer is required. A method is described where alkyl esters of both L-and D-2-hydroxyglutaric acids are prepared without side lactonization. Esterification is achieved at room temperature by reaction with appropriate alkyl chloroformates. This method avoids lactonization, in contrast to esterification with alcohols in acidic media or with diazomethane. The identity of the derivatives is established by HRGC-FTIR and HRGC-MS. Chiral HRGC separation with capillaries coated with 1(R)-trans-N-N'-1,2-cyclohexylenebisbenzamideoligodimethyL-siloxane and with a cyclodextrin is compared. The method is adequate for quantitative determinations.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190308
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  • 57
    Digitale Medien
    Digitale Medien
    Determination of cholesterol in fat and muscle of pig by HPLC and capillary gas chromatography with solvent venting injection (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 165-168 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Capillary gas chromatography ; Liquid chromatography ; Solvent venting ; Cholesterol ; Pig fat ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two methods for determination of cholesterol in fat and muscle of pig were evaluated: extraction with chloroform:methanol (2:1, v/v) followed by saponification (method 1) and direct saponification (method 2). HPLC and GC were used to determine cholesterol concentrations. GC analysis was performed with a capillary column of 100 μm using a PTV injector in the modes of cold split and solvent venting. Cholesterol was analyzed without derivatization. Both methods of extraction did not present significant differences (p 〉 0.01). Sample analysis by GC with solvent venting injection and HPLC showed the lowest % r.s.d. but GC in the cold split mode allowed to obtain a shorter analysis time. Cholesterol concentrations obtained by HPLC were not statistically different from the results obtained by GC with solvent venting injection and were slightly lower than those previously reported. Cholesterol concentrations in fat and muscle tissues respectively ranged from 52 to 77 mg/100 g and from 55 to 65 mg/100 g.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190309
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  • 58
    Digitale Medien
    Digitale Medien
    Speciation of chromium ions by capillary zone electrophoresis (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 177-179 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Capillary zone electrophoresis ; Chromium speciation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190312
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  • 59
    Digitale Medien
    Digitale Medien
    Chromatography calendar (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. VII 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190314
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  • 60
    Digitale Medien
    Digitale Medien
    Masthead (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996) 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190401
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  • 61
    Digitale Medien
    Digitale Medien
    Micellar and microemulsion electrokinetic chromatography of hop bitter acids (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 189-192 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Micellar electrokinetic chromatography (MEKC) ; Microemulsion electrokinetic chromatography (MEEKC) ; Hop acids ; Separation mechanism ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The elution order of the hop α- and β-acids has been studied under different modes of electrokinetic separation. A model is advanced to explain the shorter migration times of the more hydrophobic β-acids compared to the α-acids in micellar electrokinetic chromatography (MEKC). For quality control of the bitter principles in hops, the ruggedness of electrokinetic separation could be improved by replacing MEKC by microemulsion electrokinetic chromatography (MEEKC).
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190403
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  • 62
    Digitale Medien
    Digitale Medien
    Chromatography calendar (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 66-66 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190114
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  • 63
    Digitale Medien
    Digitale Medien
    Masthead (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996) 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190201
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  • 64
    Digitale Medien
    Digitale Medien
    Environmental applications of large volume injection in capillary GC using PTV injectors (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 69-79 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Large volume injection ; PTV injector ; Water analysis ; River sediment ; Pesticides ; Polycyclic aromatic hydrocarbons (PAHs) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Temperature programmable (PTV) injectors with packed widebore (ca. 3.5 mm i.d.) liners are used for large volume injection in capillary gas chromatography with the aim to simplify and/or improve off-line sample pretreatment proecdures. A simple procedure for optimization of large volume PTV injection is described. The system performance, i.e. linearity and repeatability, is evaluated for polar nitrogen/phosphorus containing pesticides (PTV-GC-NPD) and organochlorine pesticides (PTV-GC-ECD) in river water extracts as well as for polycyclic aromatic hydrocarbons (PAHs) in river sediment (PTV-GC-MS).
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190203
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  • 65
    Digitale Medien
    Digitale Medien
    Pulsed discharge photoionization detector: Application to analysis of chloro alkanes/alkenes (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 85-90 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A windowless pulsed discharge photoionization detector (PDPID) is described which uses the emission spectra from the discharge in helium and Ar/Kr doped helium. The emission from helium is a continuum ranging from 13.5-17.7 eV which ionizes all compounds except neon. The emission from 5.4% Ar/He ranges from 9.3-11.8 eV and ionizes most organic compounds and many inorganic compounds. The emission from 1.36% Kr/He consists principally of the resonance lines at 10.6 and 10.1 eV. These PDPIDs are used to analyze a 12 component mixture containing principally chloro alkane/alkene. The relative responses of the PDPID combined with the relative retention time can be used to qualitatively identify the chloro compounds.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190205
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  • 66
    Digitale Medien
    Digitale Medien
    Multidimensional gas chromatographic separation of selected PCB atropisomers in technical formulations and sediments (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 95-98 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chlorinated biphenyls ; Atroipisomer separation ; Multidimensional GC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A simple dual-column gas chromatographic system with a six-port switching valve has been used to separate the atropisomers of PCB congeners 84, 91, and 95 in technical PCB formulations and in extracts of soil and river sediment. A capillary column coated with a methylphenylsiloxane stationary phase (CP-Sil 8) was used as the first column, for retention window selection, and a permethylated β-cyclodextrin (ChirasilDex) capillary column as the main separation column. Because peak overlap could not be eliminated by optimization of column temperature, the enantiomeric ratios of PCB congeners could not be determined from the original chromatograms. The correct enantiomer ratio was determined from the peak areas obtained by deconvolution of the chromatograms. Whereas the PCB atropisomers considered were present in equal concentrations in the technical PCB formulations, analysis of a river sediment sample confirmed different residual concentrations of the atropisomers of congener 95.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190207
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  • 67
    Digitale Medien
    Digitale Medien
    On-column chiral derivatization of D- and L-amino acids in micellar electrokinetic chromatography by zone mixing (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 229-233 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Micellar electrokinetic chromatography (MEKC) ; D- and L-Amino acids ; On-column derivatization ; Chiral reagent (OPA/TATG) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190414
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  • 68
    Digitale Medien
    Digitale Medien
    Evaluation of incense purity using simultaneous steam distillation-extraction and HRGC analysis (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 241-242 
    Details
    ISSN: 0935-6304
    Schlagwort(e): High resolution gas chromatography ; Essential oil analysis ; Sandalwood incense composition ; Santalum album ; Simultaneous steam distillation-extraction ; Natural products chemistry ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190417
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  • 69
    Digitale Medien
    Digitale Medien
    Supercritical fluid extraction of essential oils from the fruits of Archangelica off. Hoffm. and their characterization by GC/MS (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 237-240 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Supercritical fluid extraction ; GC/MS and GC/FID ; Essential oils ; Optimization of isolation from Archangelica off. Hoffm. ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190416
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  • 70
    Digitale Medien
    Digitale Medien
    Masthead (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996) 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190501
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  • 71
    Digitale Medien
    Digitale Medien
    On-line determination of organochlorine pesticides in water by solid-phase microextraction and gas chromatography with electron capture detection (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 247-256 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography with electron capture detection ; Solid phase microextraction ; Organochlorine pesticides ; Water analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: This paper describes the extraction of 20 organochlorine pesticides (OCPs) from water samples using solid-phase microextraction (SPME). Three fused-silica fibers coated or bonded with polydimethylsiloxane (PDMS) of different film thicknesses (20-, 30-, and 100-μm) were evaluated. The extraction time, the effects of stirring and addition of NaCl to the aqueous sample, the linear range and the precision of this technique, and the effect of carryover were examined for 20 analytes and are presented here. A comparison with results using conventional liquid-liquid extraction demonstrate that the SPME technique is well suited as a fast screening technique for OCPs in water samples.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190503
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  • 72
    Digitale Medien
    Digitale Medien
    Systematic optimization of the analysis of wine bouquet components by solid-phase microextraction (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 257-262 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Solid-phase microextraction ; Food analysis ; Wine bouquet ; Monoterpenes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The extraction, identification, and quantification of wine aroma compounds are preliminary steps required for further investigation of wine quality, i.e. determination of the varieties of grapes used, the production process, and the origin and age of the wine. This paper deals with the optimization of solid-phase microextraction for the determination of compounds which produce wine bouquet. Optimum operating conditions have been determined to obtain high reproducibility at low cost and with low time-consumption. Several factors influencing the equilibrium of the aroma compounds between the sample and the fiber must be taken into account, including length of contact time between the two phases involved, speed of agitation of the sample, the matrix in which the process takes place, and, furthermore, the place, duration, and temperature of desorption in the injector of the chromatograph.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190504
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  • 73
    Digitale Medien
    Digitale Medien
    Troubleshooting in the separation sciences (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 284-284 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190509
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  • 74
    Digitale Medien
    Digitale Medien
    A four factor simplex optimization of a serially coupled open tublar columns gas chromatographic system (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 277-283 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Coupled columns ; Four factor optimization ; Simplex method ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Optimization of a gas chromatographic system with two capillary columns coupled in series in a single oven for the linear temperature programmed separation of a mixture of C1—C10 hydrocarbons has been carried out using the simplex optimization method. The following four selectivity parameters were optimized: the initial temperature of the oven; the initial hold time; the temperature programmed rate; and the pressure at the mid-point of the system. The optimization procedure was monitored by the Cp criterion.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190508
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  • 75
    Digitale Medien
    Digitale Medien
    Membrane preconcentration-capillary electrophoresis-mass spectrometry (mPC-CE-MS) analysis of 3-phenylamino-1,2-propanediol (PAP) metabolites (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 291-294 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Capillary electrophoresis-mass spectrometry ; Membrane preconcentration ; Capillary electrophoresis ; Sulfonated membrane ; Polar drug metabolites ; Toxic oil syndrome ; Eosinophilia-myalgia syndrome ; 3-Phenylamino-1,2-propanediol ; 3-Phenylamino-L-alanine ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190511
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  • 76
    Digitale Medien
    Digitale Medien
    Chromatography calendar (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. VII 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190514
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  • 77
    Digitale Medien
    Digitale Medien
    Comparative headspace analysis of fresh red coffee berries from different cultivated varieties of coffee trees (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 298-300 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Dynamic head space ; Coffee berry ; Identification ; Hypothenemus hampei ; Plant-insect relationship ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190513
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  • 78
    Digitale Medien
    Digitale Medien
    Capillary gas chromatographic evaluation of trans-fatty acid content of food produced under the traditional conditions of semi-industrial frying (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 180-182 
    Details
    ISSN: 0935-6304
    Schlagwort(e): trans-Fatty acids ; Semi-industrial frying ; Capillary GC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190313
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  • 79
    Digitale Medien
    Digitale Medien
    Determination of chelating agents in Hanford tank waste simulant by capillary zone electrophoresis (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 183-188 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chelating agents ; Complexation ; Capillary zone electrophoresis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A capillary electrophoretic method has been developed which achieves rapid quantitative separation and determination of ethylenediaminetetraacetic acid, N-(2-hydroxyethyl)ethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, and nitrilotriacetic acid in Hanford tank waste simulant (TWS). Direct UV detection of Cu2+/chelator complexes is used to achieve enhanced sensitivity. The qualitative and quantitative reliability of the method and the quality of separations, as given by efficiency and resolution, is presented. In addition, the limits of detection and linearity of detector response with concentration are given for each chelator. The selection of Cu as the UV-absorbing species over other transition metals present in the waste is discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190402
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  • 80
    Digitale Medien
    Digitale Medien
    Residues of chlorinated pesticides in eggs of the gray heron (Ardea cinerea L.): Contribution of capillary gas chromatography ion-trap mass detection (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 62-64 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Gas Chromatography ; Ion-Trap Mass Spectrometry ; Pesticide residue analysis ; Eggs ; Ardea cinera ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190112
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  • 81
    Digitale Medien
    Digitale Medien
    Troubleshooting in the separation sciences (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 65-65 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190113
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  • 82
    Digitale Medien
    Digitale Medien
    Adjusting the selectivity of inorganic anion separation by capillary electrophoresis (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 5-16 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Capillary electrophoresis ; Inorganic anions ; Decamethonium hydroxide ; Potassium dichromate ; Indirect UV detection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The separation of the principal inorganic anions (bromide, carbonate, chlorate, chloride, fluoride, nitrate, nitrite, sulfate, phosphate) has been achieved using a capillary electrophoresis system with indirect UV detection at 260 nm. Several types of cationic surfactants (quaternary ammonium, phosphonium or methonium) were tested as electroosmotic flow modifiers and added to a chromatebased buffer prepared from potassium dichromate. The influence of many physicochemical parameters such as nature and concentration of cationic surfactant, buffer pH, dichromate concentration buffer, voltage and temperature upon the migration time of an analyte anion, peak efficiency, asymmetry factor, and finally resolution has been investigated. A linear relationship between the corrected area and the anion concentration in the 2.5-50 ppm range was obtained, thus allowing the quantitative analysis of anions in mineral water. Finally, by increasing the hydrodynamic injection time, the separation of inorganic anions at a low concentration level of 50 ng/ml was achieved without any loss of resolution.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190102
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  • 83
    Digitale Medien
    Digitale Medien
    Supercritical fluid extraction of atrazine and its metabolites from soil (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 23-26 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Supercritical fluid extraction ; cGC-NPD herbicides ; CO2 modifiers ; Incurred herbicides and metabolite extraction ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Soxhlet (methanol) and SFE extraction with carbon dioxide in the presence of modifiers at different temperatures (100-200°C) for the extraction of atrazine and its main metabolites from a soil sample were compared. The most effective extraction conditions for both atrazine and its metabolites (i.e. deethylatrazine and deisopropylatrazine) were Co2 modified with 20% molar methanol-trifluoroacetic acid (MeOH-TFA) (TFA 0.65M in MeOH) at 100°C, leading to an extraction efficiency comparable with that of Soxhlet extraction with MeOH for atrazine and ca. 20% higher for its main metabolites. The relative standard deviation (RSD) of SFE was lower than that obtained by Soxhlet extraction, probably because of less interference in the cGC-NPD determination. All the other modifiers evaluated (acetone, triethylamine, and methanol) were less effective than MeOH-TFA for the extraction of atrazine and its metabolites from a soil sample, even at high molar concentrations (20%) and use of higher extraction temperatures (200°C). These results indicate the importance of matrix effects and the need of the selection of an appropriate modifier in order to obtain quantitative extractions by SFE.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190104
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  • 84
    Digitale Medien
    Digitale Medien
    Isomeric composition of the ester fraction from epicuticular waxes of Festuca arundinacea Schreb (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 43-48 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Capillary gas chromatography ; Mass spectrometry ; Wax esters ; Festuca arundinacea ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The ester portion of epicuticular waxes of tall fescue (Festuca arundinacea Schreb.) is composed of mixtures of homologous series of fatty acids esterfied with fatty alcohols. GC analyses of natural esters gave rise to the separation of several compounds of different chain length. To identify and quantify individual components in the mixture, GC/MS analyses were carried out, and the mass spectra of each peak were recorded and analyzed for characteristic ions. This approach permitted a comparison with data obtained from classical methods using GC analysis of acid and alcohol moieties obtained by hydrolysis.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190108
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  • 85
    Digitale Medien
    Digitale Medien
    Simultaneous capillary GC of acids and sugars as their silyl(oxime) derivatives: Quantitation of chlorogenic acid, raffinose, and pectin substances (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 54-58 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Optimization of GC conditions ; Sugar analysis ; Acid analysis ; Chlorogenic acid ; Raffinose ; Pectin decomposition products ; Galacturonic acid ; Arabinose ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Our GC-MS method for the simultaneous quantitation of sugars and acids as their silyl(oxime) derivatives, from one solution by one injection, has been extended to the reproducible determination of high molecular weight compounds sensitive to decomposition yet requiring a high evaporation temperature (e.g. chlorogenic acid and rffinose) and for the quantitation of the decomposition products of pectin (i.e., for the determination of galacturonic acid at low ng levels in the presence of a 10-100 fold excess of glucose eluting just before the acid). The optimized GC procedure has been used for quantitation of the sugar and acid (including chlorogenic acid) composition of potato samples, and for the determination of the increasing amount of the decomposition products of pectin substances in apple pulp after different storage times.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190110
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  • 86
    Digitale Medien
    Digitale Medien
    Characterization of polymers by multi-step thermal desorption/programmed pyrolysis gas chromatography using a high temperature PTV injector (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 193-199 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Polymer analysis ; High temperature gas chromatography ; PTV injectors ; Thermal desorption ; Pyrolysis GC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Thermal treatment hyphenated with gas chromatography is a versatile and powerful tool in the study of polymer characterization. An inexpensive system where thermal treatment at different temperatures occurs inside a Programmable Temperature Vaporization injector (PTV) is described. The samples investigated, commercial plastics, are complex mixtures that contain several polymers and additives. These plastics as well as their pure constituents are subjected to multi-step thermal treatment. The individual chromatograms of the various constituents of the polymeric sample are correlated with those of the final material in order to identify additives (thermal desorption) and degradation products (pyrolysis). Results obtained with the new method indicate the interesting potentials of the technique for the characterization of polymer compositions. Reproducibility of absolute and relative peak areas has been considered and found to be acceptable. The absence of a heated transfer line and switching valves, which are always present in conventional set-ups, eliminates the risk of losses of high molecular weight components. Further advantages of the technique proposed are simplicity, versatility, and its inexpensive nature.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190404
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  • 87
    Digitale Medien
    Digitale Medien
    Open-tubular supercritical fluid chromatography with simultaneous flame ionization and chemiluminescent nitrogen detection (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 213-216 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Supercritical fluid chromatography ; Open-tubular column ; Dual detection ; Chemiluminescent nitrogen detection ; Flame ionization detection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The use of a simultaneous detection system for open-tubular supercritical fluid chromatogrphic separation of aniline isomers, alkyl(C8 to C18)dimethylamines, a dialkylmethylamine mixture, and an extract of a Japanese horseradish power “Wasabi” is demonstrated. A chemiluminescent nitrogen detector (CLND) and a flame ionization detector (FID) were configured at the end of the open tubular column via a zero- to dead-volume tee. The dual detection was achieved with a post-column split at a 1:2.5 ratio for the CLND and FID, respectively. The optimized CLND showed virtually no response to non-nitrogenous components such as benzene, toluene, and methanol which were used as injection solvents in these applications.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190407
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  • 88
    Digitale Medien
    Digitale Medien
    Determination of trace elements. Editor: Zeer B. Alfassi. VCH, Weinheim, 1994. 607 pp., ISBN 3-527-28424-9 (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 224-224 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190410
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  • 89
    Digitale Medien
    Digitale Medien
    Ergot alkaloids as novel chiral selectors in capillary electrophoresis (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 225-226 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Capillary electrophoresis ; Chiral separation ; Ergot alkaloids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190412
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  • 90
    Digitale Medien
    Digitale Medien
    HPLC - UV determination of pesticide residues at 0.01 ppm in apple and pear pulp used for baby food (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 105-110 
    Details
    ISSN: 0935-6304
    Schlagwort(e): HPLC-UV ; Baby food ; Apple pulp ; Pear pulp ; Diflubenzuron ; Ethiofencarb ; Teflubenzuron ; Triflumuron ; Triforine ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two distinct methods are described for determination of residues of ethiofencarb and triforine, and of diflubenzuron, teflubenzuron, and triflumuron at the 0.01 ppm level in apple and pear pulp used for baby food;recoveries are above 50%. Diflubenzuron, teflubenzuron, and triflumuron are extracted with a 1:1 mixture of dichloromethane and acetone, and the extracts are cleaned by SPE using C18 as stationary phase and methanol as mobile phase. Ethiofencarb and triforine are extracted with dichloromethane, and the extracts cleaned using the same stationary phase but a 1:1 mixture of acetonitrile and water as mobile phase. Analysis of both groups of pesticides is by isocratic HPLC - UV at 210 nm using an RP-18 column and acetonitrile-water as mobile phase.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190209
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  • 91
    Digitale Medien
    Digitale Medien
    Trapping capacities of three solid phases for supercritical fluid extraction with pure carbon dioxide (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 117-120 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Supercritical fluid extraction, SFE ; Solid phases ; Analyte breakthrough ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190211
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  • 92
    Digitale Medien
    Digitale Medien
    Study of the reversed-phase high-performance liquid chromatographic separation of some pharmaceutical ingredients (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 124-126 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Reversed-phase HPLC ; Propionic antiinflammatory drugs ; Barbituric sedatives and hypnotics ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190213
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  • 93
    Digitale Medien
    Digitale Medien
    Chromatography calendar (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 128-128 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190215
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  • 94
    Digitale Medien
    Digitale Medien
    Editorial (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 129-129 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190302
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  • 95
    Digitale Medien
    Digitale Medien
    Fast electrophoretic separation of sulfur- and selenium-containig amino acid enantiomers with vancomycin as a chiral selector in coated capillaries (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 137-142 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Capillary electrophoresis ; Chiral separation ; Selenium amino acids ; Vancomycin ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Baseline separation of the enantiomers of the negatively charged 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatives of cystine, methionine, ethionine, and their seleno analogs can be achieved in 3-5 min with capillary electrophoresis in polyacrylamide coated capillaries and submillimolar concentrations of vancomycin as the chiral selector.In addition to the vancomycin concentration, the separation is affected by the type, concentration and pH of the buffer. Good buffers are more suitable than phosphate buffer. At pH values above the isoelectric point of vancomycin the mobility difference between the enantiomers becomes smaller. This effect is larger than would be expected from the reversal of the vancomycin migration alone.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190304
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  • 96
    Digitale Medien
    Digitale Medien
    Gas chromatographic separation of the stereoisomers of organophosphorus chemical warfare agents using cyclodextrin capillary columns (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 151-154 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Atomic emission spectroscopy ; Enantiomeric separation ; Cyclodextrins ; Chemical warfare agents ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The synthesis of the organophosphorus nerve agents sarin, tabun, and cyclohexyl methylphosphonofluoridate (GF) produces a mixture of two stereoisomers except for soman where four stereoisomers are produced. Significant differences exist in the reported toxicity and AChE inhibition rates of the various stereoisomers. This makes the ability to distinguish between the different stereoisomers desirable. Five different derivatized cyclodextrin stationary phases developed for gas chromatography were tested for their ability to resolve the nerve agent stereoisomers using a gas chromatograph interfaced to an atomic emission detector. Of the five columns that we examined, only the 2,6-di-O-pentyl-3-O-trifluoroacetyl or 2,6-di-O-pentyl-3-O-butyryl γ-cyclodextrins were able to successfully resolve all four soman stereoisomers. The elution order for each column was determined using solutions of isolated soman stereoisomers. Enantiomers of sarin, tabun, and GF were resolved with varying degrees of success on the different cyclodextrin stationary phases. Only the butyryl γ-cyclodextrin was able to separate the enantiomers of all four of the nerve agents examined in this study. The capacity (k) and selectivity (α) factors were determined for each of the chemical warfare agents successfully separated. The TNO Prins Maurits Laboratory in the Netherlands has previously developed several different chromatographic methods to resolve the stereoisomers of soman, sarin, and tabun. The advantage of the method described here is that commercially available cyclodextrin gas chromatography columns were used to resolve the stereoisomers, thereby facilitating rapid and routine analysis of organophosphorus nerve agents.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190306
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  • 97
    Digitale Medien
    Digitale Medien
    Sampling volatile organic compounds using a modified solid phase microextraction device (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 155-160 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Solid phase microextraction (SPME) ; Headspace analysis ; Gastight syringe ; Water analysis ; Volatile organic compounds (VOCs) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Headspace solid phase microextraction (headspace SPME) has been demonstrated to be an excellent solvent-free sampling method. One of the major factors contributing to the success of headspace SPME is the concentrating effect of the fiber coating toward organic compounds. The affinity of the fiber coating toward very volatile analytes, such as chloromethane, may, however, not be large enough for detection at the parts per trillion concentration level. Static headspace analysis, on the other hand, is very effective for these very volatile compounds. As analyte volatility decreases, the sensitivity of static headspace analysis drops. The complementary nature of these two sampling methods can be exploited by combining the SPME device with a gastight syringe. The sensitivity of the new sampling device is better than that of SPME for very volatile compounds or that of static headspace analysis for less volatile compounds. This new method can sample a wide range of compounds from chloromethane (b.p. -24°C) to bromoform (b.p. 149°C) with estimated limits of detection at the low parts per trillion level.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190307
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  • 98
    Digitale Medien
    Digitale Medien
    Troubleshooting in the separation sciences (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 176-176 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190311
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  • 99
    Digitale Medien
    Digitale Medien
    Retention in SFC at high density (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 169-175 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Supercritical fluid chromatography ; Open tubular columns ; Retention behavior ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The elucidation of the detailed mechanism of retention in supercritical fluid chromatography (SFC) is a complex problem, especially for high-density supercritical fluid mobile phases. Martire and Boehm developed a theory of SFC retention based on a statistical thermodynamic treatment, and introduced a density-squared equation for retention in SFC: In k = a + b/T + cρ + dρ/T + eρ2/T. In this paper the systems n-alkane-polydimethylsiloxane-CO2 and n-carboxylic acid methyl ester-polydimethylsiloxane-CO2 have been treated using the method introduced by Martire and Boehm. In the ranges of reduced temperature from 1.079 to 1.293 and reduced SF mobile phase density from 0.705 to 1.632, two problems were discovered in the treatment of SFC retention behavior by the method of Martire and Boehm: (1) the experimental value of the site of CO2 in the lattice field, ra, of the two systems was ca 0.9, which is obviously different from the theoretical values of 3.6 or 5.4; and (2) the difference between experimental and calculated retention values increased with increasing SF mobile phase density. The minimum in SFC retention predicted by Martire and Boehm was not observed. On the basis of some assumptions and the experimental data, the following retention equation was derived: In k = a + b/T + cρ + dρ/T + eρ2/T + fρ3/T + gρ4/T. This equation was consistent with the experimental data and can conveniently be used to explain other SFC retention behavior.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190310
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  • 100
    Digitale Medien
    Digitale Medien
    The advantage of dual-column approach and retention indices combined with refined reporting in gas chromatographic drug screening (1996)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 313-321 
    Details
    ISSN: 0935-6304
    Schlagwort(e): Capillary GC ; Drug screening ; Retention index ; Reporting ; Mean list length ; Blood analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A dual-column gas chromatographic retention index method was evaluated for the toxicological screening for basic drugs in autopsy blood samples. The dual-column approach with DB-5 and DB-1701 capillary columns doubles the Identification Power of the corresponding single column methods. The long-term intralaboratory variation of the dialkylfluoroaniline series based retention indices of drugs in blood ranged from 0.03% to 0.2% which was generally better than that obtained using the relative retention time. Novel software is described for the processing and reporting of the dual-column chromatographic data in analytically useful form. Besides retention data, the response factors served as an additional identification factor.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jhrc.1240190603
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