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991.
-Alloisoleucine (
-aIle) was obtained by the resolution of the epimer mixture of
-isoleucine (
-Ile) and
-aIle, which was formed by epimerization of
-Ile, with a resolving agent such as (2S,3S)-dibenzoyltartaric acid ((2S,3S)-DBTA) or (2S,3S)-di-4-toluoyl-tartaric acid ((2S,3S)-DTTA). 相似文献
992.
A new epidithiodioxopiperazine derivative, emethallicin A (1), was isolated along with ergosterol from the mycelial extract of the heterothallic fungus, Emericella heterothallica (mating type A). The structure of emethallicin A (1) was established on the basis of chemical and spectroscopic investigations and finally by chemical transformation to apoaranotin (11). Emethallicin A (1) has the same basic skeleton as apoaranotin (11), with C6-C2 carboxylic acid (mandelic and phenylacetic acids) diester moieties, and showed a potent inhibitory activity on histamine release from mast cells. 相似文献
993.
994.
995.
Crystallization behavior of synthetic cis-1,4 polyisoprene mixed with methyl linolate was investigated by differential scanning calorimetry and dilatometry. At isothermal crystallization temperature of ?25°C, a rate of crystallization decreased with the addition of 1 wt % methyl linolate, whereas it increased with a large amount of methyl linolate, about 30% by weight. Although Avrami constant of cis-1,4 polyisoprene was 2.82, that of mixtures containing 1 and 30 wt % methyl linolate was found to be approximately 4. This implies the same crystallization mechanism was in operation in the mixtures. Since glass transition temperature, Tg, of cis-1,4 polyisoprene decreased as the methyl linolate content of mixture increased, methyl linolate was found to be plasticizer for cis-1,4 polyisoprene. The increase in the rate of crystallization in the mixtures was corresponding to the decrease in Tg. © 1995 John Wiley & Sons, Inc. 相似文献
996.
997.
A finite element method for the analysis of two-layer density flows is presented in this paper. The standard Galerkin method based on linear interpolation functions is used to yield discrete spatial variables. For numerical integration in time, an explicit two-step selective lumping method is used. Here it is applied to a flow analysis of Ishikari Bay, at the mouth of Ishikari River. This case demonstrates a procedure that yields a numerically stable solution. 相似文献
998.
Hisayoshi Kobayashi Satohiro Yoshida Hiroshi Kato Kenichi Fukui Kimio Tarama 《Surface science》1979,79(1):189-204
Theoretical calculations have been applied to the adsorption of hydrogen molecule on flat and stepped platinum surfaces. The method of large unit cell is modified to deal with the stepped surface as well as the flat one. This method is free from the boundary effect which is inevitable in the cluster method. The results calculated for the d-band width and the highest occupied level are in good agreement with the experiments. For the dissociative adsorption, the bottom of the step site is the most favorable, and the result is attributed to the extra orbital interactions at this site. 相似文献
999.
Kenichi Furuhata Takuya Yokokawa Chang Seoul Keizo Miyasaka 《Journal of Polymer Science.Polymer Physics》1986,24(1):59-67
Single-crystal mats of ultrahigh-molecular-weight polyethylene can be drawn uniformly to high draw ratios, more than 20χ at the highest, after the necking process is completed. The dynamic mechanical modulus of the drawn mats increases markedly during the uniform drawing stage. The structural changes induced by the uniform drawing at 100°C have been followed by wide-angle and small-angle x-ray scattering, infrared absorption, differential scanning calorimetry, and birefringence. The crystallinity is estimated from the x-ray amorphous scattering intensity, the IR absorbance of gauche bands, the heat of fusion from DSC, and the density. The estimated crystallinities of the drawn mats are all very high and increase slightly and monotonically with increased drawing after necking, though the values of the crystallinity depend on the method of estimation. IR gauche bands and the SAXS peak due to the long period disappear at a draw ratio of about 80χ. All the results suggest that the uniform drawing after necking destroys the two-phase structure made up of alternately stacked crystalline and amorphous regions and then reorganizes it into a single-phase crystalline structure. 相似文献
1000.
Kenichi Ushio 《Physics letters. [Part B]》1985,158(1):71-74
One-gluon exchange (OGE) corrections to the magnetic moments of the octet baryons are studied in the bag model. It is clarified that OGE resolves a problem of μ(Λ) and μ(Ξ?) in previous quark model calculations and also improves an overall agreement between theory and experiment. 相似文献