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  • 1
    Electronic Resource
    Electronic Resource
    Structure and magnetism of Co1−xMnx alloys epitaxially grown on GaAs(001) (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 521-523 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The structure and magnetism of Co1−xMnx films grown on GaAs(001) substrates were characterized by reflection high energy electron diffraction and magneto-optical Kerr effect measurements. It is found that the Co-rich and Mn-rich films exist in body-centered-cubic and face-centered-cubic structures, respectively. Meanwhile, the Co1−xMnx films show ferromagnetism whenever the structure is bcc, but they show antiferromagnetism or paramagnetism whenever the structure is fcc. This strong correlation established between the structure and magnetism was further studied and confirmed by an ab initio electron linearized augmented-plane-wave calculation with the local-spin-density approximation. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1332093
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  • 2
    Electronic Resource
    Electronic Resource
    Fast appearances and disappearances of weak intranetwork magnetic fields
    Amsterdam : Elsevier
    Chinese Astronomy and Astrophysics 14 (1990), S. 325-337 
    Details
    ISSN: 0275-1062
    Keywords: Solar quiet regions-solar magnetic field-solar observations
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0275-1062(90)90058-L
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  • 3
    Electronic Resource
    Electronic Resource
    Theoretical and experimental studies on air gap membrane distillation (1998)
    Springer
    Heat and mass transfer 34 (1998), S. 329-335 
    Details
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Air gap membrane distillation (AGMD) is an innovative membrane separation technique for pure water extraction from aqueous solutions. In this study, both theoretical and experimental investigations are carried out on AGMD of different aqueous solutions, namely, tap water, salted water, dyed solutions, acid solutions, and alkali solutions. A simple mechanistic model of heat and mass transfer associated with AGMD is developed. Simple relationships of permeate flux, total heating or cooling load and thermal efficiency of AGMD with respect to the membrane distillation temperature difference are obtained. Effects of solution concentration and the width of the air gap in AGMD are analyzed. In the experimental study, the experiments were conducted using 1m PTFE membrane with a membrane distillation temperature difference up to 55∘C. The AGMD system yields a permeate flux of pure water of up to 28kg/m2h. Direct comparison of the experimental results with the proposed modeling predictions shows a fairly good match.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002310050267
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  • 4
    Electronic Resource
    Electronic Resource
    Pull-out and fragmentation in model fibre composites (1991)
    Springer
    Journal of materials science 26 (1991), S. 2467-2476 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract An experimental study has been carried out of debonding and fibre rupture in model composites. A single glass rod or fibre was embedded in the centre of a long transparent silicone rubber block. Strains in the rubber in close proximity to the rod or fibre were measured as the specimen was slowly stretched. Pull-out forces, strain distributions, and debonded lengths are compared with the predictions of a simple theory based on a fracture energy criterion for debonding, and taking into account friction at the debonded interface. Experiments were carried out with rods of different diameter, rubber blocks of varied cross-section, and with two levels of adhesion. By extrapolating the debonded length to zero, values of the debonding force in the absence of friction were obtained. They were in accord with fracture energies of about 50 J/m2 for weak bonding and about 200 J/m2 for strong bonding. Fibre fragmentation lengths were measured also. They were in reasonable agreement with the inferred fracture energies and the measured frictional properties of silicone rubber sliding on glass. In a separate study, it was found that the frictional stress between cast silicone rubber and glass was approximately constant, about 0.1 MPa, rather than proportional to pressure, for pressures exceeding about 0.02 MPa. This feature is attributed to a particularly smooth interface between the two materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01130197
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  • 5
    Electronic Resource
    Electronic Resource
    A unified variational theory of hybrid problems for fully 3-D transonic rotor-flow with shocks. Part I. Potential flow (1995)
    Springer
    Acta mechanica 108 (1995), S. 207-217 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Based on [3], the unified variable-domain variational theory of hybrid problems for rotor-flow [1], [2], [16], [24] is extended to fully 3-D transonic rotor-flows with shocks, unifying and generalizing the direct and inverse problems. Three variational principle (VP) families together with a general form of generalized VPs have been established, taking distributed suction and/or blowing along blade- and annular walls into account. All unknown boundaries are successfully handled via functional variations with variable domain, converting almost all boundary and interface conditions, including the Rankine-Hugoniot shock relations, into natural ones. This theory provides a series of novel ways for blade design and a theoretical basis for finite element applications and also constitutes an important part of the optimal design theory of rotor-bladings [6]. Numerical solutions by finite elements in [22]–[24] show good agreement with experimental results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01177339
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  • 6
    Electronic Resource
    Electronic Resource
    Derivation and transformation of variational principles with emphasis on inverse and hybrid problems in fluid mechanics: a systematic approach (2000)
    Springer
    Acta mechanica 140 (2000), S. 73-89 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A systematic approach to the derivation of variational principles (VPs) from the partial differential equations of fluid mechanics is suggested herein, consisting essentially of two major lines: (1) establishing a first VP via reversed deduction followed by extending it successively to a family of subgeneralized VPs via a series of transformations, and (2) vice versa. Full advantage is taken of four powerful means — the functional variation with variable domain, the natural boundary/initial condition (BC/IC), the Lagrange multiplier, and the artificial interface. The occurrence of three kinds of variational crisis is demonstrated and methods for their removal are suggested. This approach has been used with great success in establishing VP-families in fluid mechanics with special attention to inverse and hybrid problems of flow in a rotating system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01175982
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  • 7
    Electronic Resource
    Electronic Resource
    A variable-domain variational formulation of inverse problemI A of 2-D unsteady transonic flow around oscillating airfoils (1999)
    Springer
    Acta mechanica 137 (1999), S. 195-209 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The present paper carries out, for the first time, a detailed theoretical investigation on the inverse problem in unsteady aerodynamics. Special attention is paid to finding proper ways of problem-posing and mathematical formulation. To demonstrate the basic idea, only an inverse problem of typeI A of unsteady transonic flow with shocks around oscillating airfoils is studied herein. It has been formulated by a family of variational principles (VP) with variable domain, in which all unknown boundary (airfoil contour) and discontinuities (shocks and free trailing vortex sheets) are handled (captured) via the functional variation with variable domain. As a result, almost all boundary- and interface-conditions have been converted into natural ones. Thus, a rigorous theoretical basis for unsteady airfoil design and finite element (FE) applications is provided. On the basis of these variational principles developed in this paper, a method using new self-deforming finite element is suggested for the numerical realization of the variable-domain variation of the functional and a numerical example is given. Its suitability and effectiveness are demonstrated by the numerical results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01179209
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  • 8
    Electronic Resource
    Electronic Resource
    Variational principles and generalized variational principles for fully 3-D transonic flow with shocks in a turbo-rotor part II. Rotational flow (1993)
    Springer
    Acta mechanica 97 (1993), S. 229-238 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Two variational principle (VP) families for fully 3-D transonic potential, Beltrami rotational flows with shocks in a rotor are put forth in terms of stream functions. By making use of functional variations with variable domain one succeeded in converting most of the boundary conditions and matching conditions across unknown discontinuities (such as shocks and free trailing vortex sheets), including the generalized Rankine-Hugoniot shock relations, into natural ones. This paper is intended to provide a rigorous theoretical foundation for constructing a novel computational method which incorporating a new finite element with self-adapting embedded discontinuities (now under development) and the artificial density concept, could capture all unknown discontinuities automatically and clearly. The applicability of VPs for rotational flow, in contrast to those for Beltrami flow, is not limited to transonic flow with moderate Mach numbers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01176528
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  • 9
    Electronic Resource
    Electronic Resource
    A variable-domain variational theory using Clebsch variables for hybrid problems of 2-D transonic rotational flow (1993)
    Springer
    Acta mechanica 99 (1993), S. 219-223 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary By means of functional variations with variable domain the variational principles of [7], [8] are extended to inverse and hybrid flow problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01177247
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  • 10
    Electronic Resource
    Electronic Resource
    Improved scalar-vector potential formulations of 3-D compressible rotational flow (1992)
    Springer
    Acta mechanica 92 (1992), S. 237-240 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary It is shown, that the vector potential Ψ of the solenoidal part of a 3-D vector field can be simplified by a term-condensing method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01174179
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