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31.
High P-T Raman measurements of solid and fluid hydrogen to above 1100 K at 70 GPa and to above 650 K in 150 GPa range, conditions previously inaccessible by static compression experiments, provide new insight into the behavior of the material under extreme conditions. The data give a direct measure of the melting curve that extends previous optical investigations by up to a factor of 4 in pressure. The magnitude of the vibron frequency temperature derivative (dnu/dT)(P) increases by a factor of approximately 30 over the measured pressure range, indicating an increase in intrinsic anharmonicity and weakening of the molecular bond. 相似文献
32.
Manabu Yamamoto Keiji Urata Kiyoto Murashige Yuroku Yamamoto 《Spectrochimica Acta Part B: Atomic Spectroscopy》1981,36(7):671-677
A method is described for the differential determination of As(III) and As(V). and Sb(III) and Sb(V) by hydride generation-atomic absorption spectrophotometry with hydrogen-nitrogen flame using sodium borohydride solution as a reductant. For the determination of As(III) and Sb(III), most of the elements, other than Ag+, Cu2+, Sn2+, Se4+ and Te4+, do not interfere in an at least 30,000 fold excess with respect to As(III) or Sb(III). This method was applied to the determination of these species in sea water and it was found that a sample size of only 100 ml is enough to determine them with a precision of 1.5–2.5%. Analytical results for surface sea water of Hiroshima Bay were 0.72 μgl?1, 0.27 μgl?1 and 0.22 μgl?1 for As(total), As(III) and Sb(total), respectively, but Sb(III) was not detected in the present sample. The effect of acidification on storage was also examined. 相似文献
33.
Ken’ichiro?TanakaEmail author Sunao?Murashige Shin’ichi?Oishi 《Numerische Mathematik》2004,97(3):537-554
Summary. This paper describes numerical verification of a double turning point of a nonlinear system using an extended system. To verify the existence of a double turning point, we need to prove that one of the solutions of the extended system corresponds to the double turning point. For that, we propose an extended system with an additional condition. As an example, for a finite dimensional problem, we verify the existence and local uniqueness of a double turning point numerically using the extended system and a verification method based on the Banach fixed point theorem.Mathematics Subject Classification (2000): 65J15, 65G20, 65P30 相似文献
34.
Motozaki T Sawamura K Suzuki A Yoshida K Ueki T Ohara A Munakata R Takao K Tadano K 《Organic letters》2005,7(11):2261-2264
[reaction: see text]. Starting from diethyl (R)-malate, synthesis of the lower-half segment of (+)-tubelactomicin A, a 16-membered macrolide antibiotic, has been achieved. The synthesis involved the highly endo- and pi-facial selective intramolecular Diels-Alder reaction achieved using a trisubstituted methacrolein derivative tethering a 10-carbon dienyne unit at the beta-carbon, which in turn was prepared from a known allylated malic acid derivative. 相似文献
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36.
Cellulose - Tensile tests of birch cork were performed in the tangential direction. Birch cork in the wet state showed significantly higher extensibility than those in the dried state. The... 相似文献
37.
Hidemasa Takao Osamu Abe Hidenori Yamasue Shigeki Aoki Kiyoto Kasai Hiroki Sasaki Kuni Ohtomo 《Magnetic resonance imaging》2010
The hemispheres of the human brain are functionally and structurally asymmetric. The purpose of this study was to evaluate the effects of aging on gray and white matter asymmetry. Two hundred twenty-six right-handed normal volunteers aged 21–71 years were included in this study. The effects of aging on gray matter volume asymmetry and white matter fractional anisotropy asymmetry were evaluated with use of voxel-based morphometry and voxel-based analysis of fractional anisotropy maps derived from diffusion tensor imaging (DTI), respectively. The voxel-based morphometry showed no significant correlation between age and gray matter volume asymmetry. The voxel-based analysis of DTI also showed no significant correlation between age and white matter fractional anisotropy asymmetry. Our results showed no significant effects of aging on either gray matter volume asymmetry or white matter fractional anisotropy asymmetry. 相似文献
38.
The polarization dependence of the one- and two-phonon Raman scatterings of the amorphous semiconductor AsxSe1?x systems for 0 ? x ? 0.5 was measured. The analysis of the Raman data by the superposition of the vibrations of AsSe3 pyramids and SeSe bonds suggests the existence of the intermediate range interaction in the AsxSe1?x systems.Two phonon Raman spectra for 0.3 ? x are explained by the combination plus overtone of the first order Raman scatterings. For x ? 0.2, however, the overtone processes become predominant.The dependence of the Raman spectra on the As concentration suggests that the chemical orderings are predominant. 相似文献
39.
Kiyoto Edo Michinao Mizugaki Yoshio Koide Haruo Seto Kazuo Furihata Noboru Ōtake Nakao Ishida 《Tetrahedron letters》1985,26(3):331-334
The structure of the chromophore of an antitumor antibiotic neocarzinostatin has been elucidated as a bicycro[7,3,0]dodecadiyne system having naphthalenecarboxylic acid, aminosugar and ethylene carbonate units. 相似文献
40.
Amorphous Ge1−XSX films with Ge-rich composition of 0X0.62 were prepared by the laser ablation method to investigate the effect of sulfur on optical properties. From Raman spectra, it is found that the structure changes gradually with composition X. The change of properties from tetrahedral to chalcogenide semiconductors was examined in terms of photodarkening phenomena. As X increased, the photodarkening effect began to be observed at X=0.2 and enhanced significantly at X=0.5. 相似文献