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71.
Masuhiro Tsukada Giuliano Freddi Yoko Gotoh Nobutami Kasai 《Journal of Polymer Science.Polymer Physics》1994,32(8):1407-1412
Physical and chemical structure, as well as thermal behavior of solution-cast regenerated films, prepared from tussah (Antheraea pernyi) silk fibroin, were compared with those of solution-cast native films, in order to ascertain whether treatment (degumming, dissolution) used for preparation affected their properties. Regenerated fibroin films exhibited a higher thermal stability than native ones, as shown by differential scanning calorimetry, thermomechanical analysis, and dynamic mechanical behavior. Glass transition temperature and other relevant thermal transitions of the regenerated silk specimen shifted to higher temperatures compared with those of native specimen. Molecular conformation and crystalline structure did not show significant differences between the two kinds of silk films. Amino acid composition and molecular weight, however, distribution changed markedly after dissolving tussah silk fibroin fiber in concentrated LiSCN in polypeptide size was the main features for the regenerated silk fibroin. © 1994 John Wiley & Sons, Inc. 相似文献
72.
We have investigated theoretically the Nernst effect in unconventional (d-wave) charge and spin density waves (UDW). In the presence of magnetic field, Landau levels are formed, and the gapless behaviour of the low energy excitations change into gapped behaviour. When additional electric field is applied, the quasiparticles drift with a velocity of E × B/B2, and carry entropy. From this, the Nernst coefficient can be calculated using the Kelvin relation. The present results account very nicely for the measured Nernst signal in the pseudogap phase of high Tc superconductor La2−xSrxCuO4 and Bi2Sr2−yLayCuO6. This indicates that the large Nernst effect is a clear signiture of UDW. 相似文献
73.
The transmission eigenchannels of A1 and Na atom bridges formed between jellium electrodes are investigated by a first-principles calculation. A transparent view on electronic transport in atom-size structures is provided by the decomposition of electronic states into eigenchannels. In particular we show how LDOS and current density resolved into eigenchannels reflect the spatial nature of atomic orbitals of the atoms composing the nanostructures. On the other hand, the eigenchannel DOS has already for the straight three-Al-atom bridge a 1D band character. From this we conclude that the transport through the single A1 atom in this case mainly has a 1D character (channel) in contrast to a 0D resonant tunneling (dot) character. The effect of the bending of the bridge shape is significant for the A1 bridges, but not for the Na bridges. 相似文献
74.
Shinichi Ueji Kazumi Nakatsu Hiroshi Yoshioka Kenji Kinoshita 《Tetrahedron letters》1982,23(11):1173-1176
The crystals of the title compound contain both intra- and inter-molecular OH?π hydrogen bonds (the first example of bifurcated OH?π bonds), the stereochemistry of which has been elucidated by an X-ray structure analysis; this bifurcated bond is also supported by the observation based on the IR spectrum of the crystals. 相似文献
75.
The present article reports a new optical method for real time addition or subtraction of two photographic images. Two transparencies which are placed in the two arms of a Mach-Zehnder interferometer with two orthogonal polarizers are subsequently added or subtracted by rotating an analyser inserted in the output beam. A linear combination of the amplitudes of the two images can also be observed for different orientations of the transmission axis of the analyser. Some experimental results are presented. 相似文献
76.
Watanabe Kazumi 《International Journal of Solids and Structures》1977,13(1):63-74
The well-known Cagniard's technique seems very useful for analyzing the transient problem of an elastic body subjected to a moving load with uniform velocity, but, in the cases of non-uniform velocity it would be difficult to apply the technique directly to analyze the problem. For such cases, instead of the technique, the convolution theorem of the Laplace transform or the dynamic Betti-Rayleigh reciprocal theorem has been applied usefully by many authors.In this paper, an inversion scheme which enables us to apply the Cagniard's technique directly to those difficult problems is presented by solving the problem of a reciprocating anti-plane shear load applied to a layered elastic half space. In this treatment it will be found clearly that our technique is simpler and more systematic than any other techniques for solving the problem. Numerical results are shown in the form of curves and the wave-front singularities are also investigated. 相似文献
77.
We derive time dependent Ginzburg-Landau equations for strong coupling superconductors. It is shown that due to a certain separability of the order parameter the equation for it’s time dependent fluctuations is again of diffusion type. Strong coupling effects show up only in the numerical coefficients of the diffusion equation. We apply our findings to the problem of electrical resistivity in strong coupling superconducting materials above the transition temperatureT c. 相似文献
78.
Electronic structure of Cl covered Si (111) 7 × 7 surface is calculated on the basis of the first principle DV-Xα cluster method. Two typical reconstruction models of the Si (111) 7 × 7 surface, i.e. the buckled and the vacancy models, are investigated in detail. The vacancy model, where two chemisorption sites of onefold and threefold coordinated geometries coexist, can explain the polarization dependences of the recent ultravioler photoemission spectroscopy (UPS) results. 相似文献
79.
Feng Dang Kazumi Kato Hiroaki Imai Satoshi Wada Hajime Haneda Makoto Kuwabara 《Ultrasonics sonochemistry》2010,17(2):310-314
A new effect of ultrasonic irradiation on the formation of BaTiO3 particles was identified. Ultrasonication caused the aggregation of the original 5–10 nm BaTiO3 particles in the same crystal axis and accelerated the formation of BaTiO3 particles significantly. Furthermore, narrow size distribution was obtained for the aggregated particles under ultrasonic irradiation. 相似文献
80.
Inagaki K Takatsu A Nakama A Eyama S Yarita T Okamoto K Chiba K 《Analytical and bioanalytical chemistry》2006,385(1):67-75
A method is described for determination of selenium in sediment by isotope-dilution inductively coupled plasma mass spectrometry
with an octapole reaction cell (ID–ICP–ORCMS). Sediment samples were digested with HNO3, HClO4, and HF, and the digestion included an elaborate evaporation process to remove bromine from the digested solution. Simple
strong cation-exchange disk filtration was used to remove rare earth elements (REE) from the digested solution, because REE2+ seriously interfere with Se isotopes (i.e. 156Gd2+ with 78Se+, 160Gd2+ with 80Se+). Addition of acetic acid to the filtrate was examined to improve the sensitivity of ICP–ORCMS measurement of Se+ by means of a carbon-enhancement effect. The interfering for selenium isotopes were almost eliminated by use of H2 as reaction gas. Interference from BrH+ formed in the reaction cell was negligible because the Br was removed in the evaporation process. Approximately 99.5% of
REE were removed by cation-exchange disk filtration yet more than 99% of Se remained in the filtrate solution. The intensity
for Se+ was enhanced approximately fourfold by addition of 5% (v/v) of acetic acid whereas that for was barely enhanced. Measured 80Se/78Se ratios in unspiked digested solutions of the sample were in good agreement with that for an Se standard solution. The analytical
results for Se in the certified reference materials MESS-3 and PACS-1 were in good agreement with their certified values,
with small uncertainties.
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