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  • 1
    Electronic Resource
    Electronic Resource
    Ab initio studies on the electronic structures of strained-layer superlattices (InAs)n(InP)n(001), (n=1–5) (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 2556-2563 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report ab initio studies on the electronic structures of strained-layer superlattices (SLSs) (InAs)n(InP)n(001), (n=1–5) under three different strain conditions via a linearized muffin-tin-orbital method with two treatments for d states. The effects of In 4d orbitals on the band structure and the valence band offset (VBO) are investigated. The hydrostatic pressure behavior and the Γ–X mixture in these SLS systems are also discussed. It is found that the band gap of the InP/InAs system is insensitive to its layer thickness. The VBO values at the SLS's under the three strain conditions are determined by a frozen potential approach. Our results demonstrate that for the InP/InAs system the bulklike property is almost recovered in the molecular layer next to the interface. This behavior may be due to the common cation on both sides of the interface. This makes the frozen-potential approach converge very fast with the layer thickness. Our results of band structure for the (1+1) SLS under a free-standing mode are consistent with those given by a more elaborate full-potential linearized augmented-plane-wave (FLAPW) calculation. The present results of VBO are about 0.07–0.09 eV larger than the data from an x-ray photoelectron spectroscopy measurement and the FLAPW method, while in good agreement with the results given by the model solid theory. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358717
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  • 2
    Electronic Resource
    Electronic Resource
    Average bond energy model for determining valence-band offsets at strained heterointerfaces Si,Ge,InP,GaAs/GexSi1−x (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 872-879 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A full description is presented of the "average bond energy model,'' which was developed for the determination of valence-band offset at heterojunctions. It is shown that this model is related conceptually to Harrison's tight binding "pinned'' model, while it overcomes all of the shortcomings of the latter. Its final form turns out to be a generalization of Cardona's dielectric-midgap-energy model. The average bond energy model is also shown related to Tersoff's charge-neutrality-point model. In this article, this model is used in conjunction with a cluster expansion method to determine systematically the valence-band offsets at four strained alloy type heterointerfaces, Si,Ge,InP,GaAs/GexSi1−x as functions of the alloy composition x. Good agreement is found between our results and available experimental data. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362896
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  • 3
    Electronic Resource
    Electronic Resource
    Correlations of vorticity and material line elements with strain in decaying turbulence (1996)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 8 (1996), S. 2203-2214 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Correlations of the vorticity and the passive material line element with strains in decaying turbulence are investigated. The mean principal rates of the strain and the growth rates of the vorticity and the material line element due to the nonlinear stretching are all found to be proportional to the square-root-mean enstrophy. The ratios of the principal rates are 4:1:−5. It is shown how these ratios help determining the values of free parameters in the phenomenological models of turbulence such as the Burgers vortex model proposed by Ashurst (private communication) and the Lundgren–Townsend vortex model by Pullin and Saffman [Phys. Fluids A 5, 126 (1993); 6, 3010 (1994)]. The mean growth rate of material line elements is slightly larger than the intermediate principal rate, but much less than the most positive one. Numerical results show that the material line element has nearly the same preferences in aligning with the principal directions of the strain corresponding to the mostly positive and the intermediate principal rates. The growth rate is approximately linearly correlated with the strain magnitude but almost uncorrelated with the vorticity magnitude. Conditional statistics and a simple model flow have been used to explain the above observations. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.868993
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  • 4
    Electronic Resource
    Electronic Resource
    Power-law decay of homogeneous turbulence at low Reynolds numbers (1994)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 6 (1994), S. 3765-3775 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The decay of nominally isotropic, homogeneous incompressible turbulence is studied by direct numerical simulations for Reλ in the range (5–50) with 2563 spectral coefficients. A power-law decay of the turbulent energy is observed with exponents approximately equal to 1.5 and 1.25, apparently dependent on Reλ. A new complete similarity form for the double and triple velocity correlation functions, f(r,t) and k(r,t), is proposed for low to intermediate Reλ that is consistent with the Kármán–Howarth equation and the results of the numerical experiments. The results are also consistent with Saffman's proposed asymptotic behavior of f(r,t) for large separation r for runs with a decay exponent of 1.5. The so-called final period of decay is not observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.868366
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  • 5
    Electronic Resource
    Electronic Resource
    Velocity autocorrelations of decaying isotropic homogeneous turbulence (1995)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 7 (1995), S. 2455-2464 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Velocity autocorrelations and the mean-square displacements of fluid particles are obtained for decaying, isotropic homogeneous turbulence by numerical simulation of the flow field, using 1283 and 2563 grids, and tracking several tens of thousands of fluid particles, using a third-order interpolation scheme. A self-preserving Lagrangian velocity autocorrelation coefficient is found in terms of a dimensionless time variable s, defined by ds=dt/Ts(t), under the observation of a power-law energy decay and the assumption that Ts(t) is proportional to the Lagrangian integral timescale TL. This timescale is in turn assumed to be proportional to the length scale of the energy-containing eddies Le∼K3/2/ε divided by the turbulent velocity u′, where K=3/2u′2 is turbulent energy and ε is the energy dissipation rate. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.868780
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  • 6
    Electronic Resource
    Electronic Resource
    New HLA–DPB1 alleles generated by interallelic gene conversion detected by analysis of sperm (1995)
    [s.l.] : Nature Publishing Group
    Nature genetics 10 (1995), S. 407-414 
    Details
    ISSN: 1546-1718
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] The rate at which allelic diversity at the HLA loci evolves has been the subject of considerable controversy. The patchwork pattern of sequence polymorphism within the second exon of the HLA class II loci, particularly in the DPB1 locus, may have been generated by segmental exchange (gene ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/ng0895-407
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  • 7
    Electronic Resource
    Electronic Resource
    Cationic ring-opening polymerization of 2-phenyl-1,3,6,2-trioxaphosphocane (1981)
    Springer
    Polymer bulletin 4 (1981), S. 185-191 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The ring-opening polymerization of 2-phenyl-1,3,-6,2-trioxaphosphocane (4), an eight-membered cyclic phosphonite, has been investigated. Cationic initiators of PhCH2-Cl and MeOTf gave polymers, whereas anionic and radical initiators did not yield polymer. The structure of polymer was examined by IR, 1H, 31P, and 31C NMR spectroscopy of polymers and elemental analysis as well as the alkaline hydrolysis products. The polymer consisted of two different units, i.e., the major part is the “normal” phosphinate structure 5 and the minor part is the isomerized unit 6 in 7% with PhCH2Cl initiation and in 34% with MeOTf initiator. The difference in nature of propagating species from these two initiators are discussed in connection with their reactivities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00263060
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  • 8
    Electronic Resource
    Electronic Resource
    Polymerization of acrylic acid initiated with poly-γ-mercaptopropylsiloxane (1983)
    Springer
    Polymer bulletin 9 (1983), S. 5-10 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A water soluble polyacrylic acid has been obtained by polymerization of acrylic acid initiated with silica-supported poly-γ-mercaptopropylsiloxane in the presence of water and carbon tetrachloride. A super absorbent sodium polyacrylate (water absorbing capacity 300 g/g) has been prepared by copolymerization of acrylic acid with a small amount of p-divinylbenzene with the same initiator in a mixture of aqueous sodium hydroxide solution, carbon tetrachloride, n-hexane and Tween 80.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00275560
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  • 9
    Electronic Resource
    Electronic Resource
    Spontaneous copolymerizations of 2-phenyl-1,3,6,2-trioxaphosphocane with α,β-unsaturated acids and with α-keto acids (1982)
    Springer
    Polymer bulletin 6 (1982), S. 389-393 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary 2-Phenyl-1,3,6,2-trioxaphosphocane(1), an eight-membered cyclic phosphonite, was copolymerized withα,ß-unsaturated acids and with α-keto acids. The copolymerization took place above room temperature without added catalyst. The copolymerizations of1 with α,ß-unsaturated acids of acrylic and methacrylic acids (2) afforded polyphosphinates (3), alternating copolymers of1 and2. On the other hand, the combinations of1 with α-keto acids of pyruvic and phenylglyoxylic acids (5) gave copolymers (6) consisting of alternating unit6α and α-ester unit6ß formed via the deoxygenation of5 by1 (“Deoxy-Copolymerization”).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00959848
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  • 10
    Electronic Resource
    Electronic Resource
    Selective permeabilities of chitosan-acetic acid complex membrane and chitosan-polymer complex membranes for oxygen and carbon dioxide (1988)
    Springer
    Polymer bulletin 20 (1988), S. 83-88 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Chitosan-acetic acid complex membrane and several chitosan-polymer complex membranes have been prepared and the gas permeabilities of these membranes have been examined. It has been found that chitosan-acetic acid complex membrane shows high permselectivities for oxygen and carbon dioxide, and synthetic polymers can modify the permeation behavior of chitosan membrane for oxygen and carbon dioxide. The separation factor αCO2/O2 of these membranes were much smaller than unity, indicating possible applications for the preservations of fruits and vegetables. It has been noticed that the permeation behaviors of these membranes are markedly influenced by metal ions added into the membranes and the membranes have good mechanical strength.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00262253
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