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  • 1
    Electronic Resource
    Electronic Resource
    Nonlinear morphological instabilities in directional solidification—an integral approximation (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 2765-2772 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this article, we derive a strongly nonlinear evolution equation by using the integral method to study the instabilities in a directionally solidified binary mixture. This equation can not only describe the interfacial behaviors of all the long-wave limits, but can also provide the possibility of strongly nonlinear instability analyses. Weakly nonlinear analyses proceeded from the critical conditions are undertaken to investigate the two-dimensional bifurcation types and a transition curve separating subcritical and supercritical ranges is obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357541
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  • 2
    Electronic Resource
    Electronic Resource
    Structural heterogeneity in the R173 family of rye-specific repetitive DNA sequences (1992)
    Springer
    Plant molecular biology 20 (1992), S. 95-102 
    Details
    ISSN: 1573-5028
    Keywords: nucleotide sequence ; repeated DNA sequence, rye ; (Secale cereale) ; transposon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The rye-specific R173 family of repeated DNA sequences consists of ca. 15 000 individual copies per diploid rye (Secale cereale) genome and is distributed over all 7 rye chromosomes in a dispersed manner. Individual R173 elements vary in size between 3 and 6 kb, are generally not arranged as tandem repeats and are flanked by both multi-copy and single-copy sequences. DNA sequence analysis of three R173 elements (R173-1, R173-2 and R173-3) demonstrated a high degree of homology in conserved domains. The structure of R173-1 was quite different from the other two elements: long direct repeats, which represent a rye-specific repetitive sequence, were found at the ends and a 600 bp long domain was replaced by an unrelated sequence of approximately equal size. R173-2 and R173-3 were extremely similar to each other with the exception of a terminal truncation of R173-2. No open reading frames for proteins 〉20 kDa were present and a database search failed to detect significant homologies to published protein sequences. Despite the transposon like genomic organisation of the R173 family, individual elements lacked sequence features frequently associated with transposons and retrotransposons. In contrast, two of the regions flanking R173 elements showed strong DNA homologies to a 850 bp long region of a proposed wheat retrotransposon and to a 300 bp long region downstream of the wheatGlu-D1 gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029152
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  • 3
    Electronic Resource
    Electronic Resource
    Numerical dosimetry at power-line frequencies using anatomically based models (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 13 (1992), S. 43-60 
    Details
    ISSN: 0197-8462
    Keywords: scaled frequency FDTD method ; induced current densities ; pure electric or magnetic fields ; combined electric and magnetic fields ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: We have used the finite-difference time-domain (FDTD) method to calculate induced current densities in a 1.31-cm (nominal 1/2 in) resolution anatomically based model of the human body for exposure to purely electric, purely magnetic, and combined electric and magnetic fields at 60 Hz. This model based on anatomic sectional diagrams consists of 45,024 cubic cells of dimension 1.31 cm for which the volume-averaged tissue properties are prescribed. It is recognized that the conductivities of several tissues (skeletal muscle, bone, etc.) are highly anisotropic for power-line frequencies. This has, however, been neglected in the first instance and will be included in future calculations. Because of the quasi-static nature of coupling at the power-line frequencies, a higher quasi-static frequency f′ may be used for irradiation of the model, and the internal fields E′ thus calculated can be scaled back to the frequency of interest, e.g., 60 Hz. Since in the FDTD method one needs to calculate in the time domain until convergence is obtained (typically 3-4 time periods), this frequency scaling to 5-10 MHz for f′ reduces the needed number of iterations by over 5 orders of magnitude. The data calculated for the induced current and its variation as a function of height are in excellent agreement with the data published in the literature. The average current densities calculated for the various sections of the body for the magnetic field component (H) are considerably smaller (by a factor of 20-50) than those due to the vertically polarized electric field component when the ratio E/H is 377 ohms. We have also used the previously described impedance method to calculate the induced current densities for the anatomically based model of the human body for the various orientations of the time-varying magnetic fields, namely from side to side, front to back, or from top to bottom of the model, respectively. 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250130706
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  • 4
    Electronic Resource
    Electronic Resource
    A frequency-dependent finite-difference time-domain formulation for induced current calculations in human beings (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 13 (1992), S. 543-555 
    Details
    ISSN: 0197-8462
    Keywords: broadband irradiation ; short pulses ; tissue dispersion ; induced currents ; SARs ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The finite-difference time-domain (FDTD) method has been used to calculate SARs and induced currents involving whole-body or partial-body exposures of models to spatially uniform or nonuniform (far-field or near-field), to sinusoidally varying EM fields, or to transient fields such as those associated with electromagnetic pulses. However, a weakness of the FDTD algorithm is that the dispersion of the tissue's dielectric properties is ignored and frequency-independent properties are assumed. Although this is permissible for continuous-wave or narrow-band irradiation, the results may be highly erroneous for short pulses, in which ultra-wide bandwidths are involved. In some recent publications, procedures are described for one- and two-dimensional problems for media in which the complex permittivity ∊ * (ω) may be described by a single-order Debye relaxation equation or a modified version thereof. These procedures based on a convolution integral describing D(t) in terms of E(t) cannot be extended to human tissues for which multiterm Debye relaxation equations must generally be used.We describe here a new differential-equation approach that can be used for general dispersive media. We illustrate the use of this approach by one- and three-dimensional examples of media for which ∊ * (ω) is given by a multiterm Debye equation, and for an approximate two-thirds muscle-equivalent model of the human body. Based on a single run involving a Gaussian pulse, the frequency-dependent FDTD [(FD)2TD] method allows calculations of SARs and induced currents at various frequencies by taking the Fourier components of the induced E fields. The (FD)2TD method can also be used to calculate coupling of the short (ultra-wideband) pulses to the human body. 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250130609
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  • 5
    Electronic Resource
    Electronic Resource
    Polymerization of acrylonitrile initiated by vanadium(V)-thiourea reaction (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 1289-1296 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1990.080280527
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    Paper (German National Licenses)
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