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971.
972.
973.
A Chamber for X-Ray Diffractometry of Gas Hydrates Samples for Pressures of Up to 700 atm 总被引:1,自引:0,他引:1
V. V. Feklistov A. Kh. Timchenko A. I. Ancharov M. A. Sheromov A. Yu. Manakov 《Instruments and Experimental Techniques》2005,48(6):826-828
A chamber for X-ray diffractometry of gas-hydrate samples designed for operation at pressures of up to 700 atm and low temperatures is described. The leakproof character of the chamber at temperatures down to ?150°C is ensured by an Amaga-type seal with a fluoroplastic gasket pressed by disk springs. The chamber was used to study double hydrates using a synchrotron radiation source and a pressure generator based on a thermal multiplier. 相似文献
974.
T. I. Voronina T. S. Lagunova M. P. Mikhaĭlova K. D. Moiseev A. F. Lipaev Yu. P. Yakovlev 《Semiconductors》2006,40(5):503-520
The results of detailed study of the magnetotransport properties of broken-gap type II heterojunctions in a GaInAsSb/InAs(GaSb) system are reported. An electron channel with a high charge-carrier mobility (as high as 50000–60000 cm2/(V s)) is observed and studied for the first time in an isotype broken-gap p-GaInAsSb/p-InAs heterostructure. The effects of electron-channel depletion and semimetal-semiconductor transition in the case of heavy doping of the quaternary alloy with acceptors are studied. Magnetotransport properties at temperatures of 4.2–200 K are studied in detail. Data on the energy spectrum and parameters of two-dimensional charge carriers at the heteroboundary are obtained. It is ascertained experimentally that, depending on the composition, either staggered (at x = 0.85) or broken-gap (at x = 0.95) heterojunctions can be formed in the Ga1?x InxAsySb1?y /GaSb, which is confirmed by theoretical calculations. The anomalous Hall effect and negative magnetoresistance were observed in GaInAsSb/InAs:Mn grown on substrates doped heavily with Mn magnetic acceptor impurity so that the hole concentration was as high as p > 5 × 1018 cm?3; these phenomena are caused by exchange interaction of Mn ions in InAs with high-mobility charge carriers in the electron channel at the heterointerface. 相似文献
975.
YS Jung IR Vassiliev J Yu L McIntosh JH Golbeck 《Canadian Metallurgical Quarterly》1997,272(12):8040-8049
A psaC deletion mutant of the unicellular cyanobacterium Synechocystis sp. PCC 6803 was utilized to incorporate site-specific amino acid substitutions in the cysteine residues that ligate the FA and FB iron-sulfur clusters in Photosystem I (PS I). Cysteines 14 and 51 of PsaC were changed to aspartic acid (C14DPsaC, C51DPsaC, C14D/C51DPsaC), serine (C14SPsaC, C51SPsaC), and alanine (C14APsaC, C51APsaC), and the properties of FA and FB were characterized by electron paramagnetic resonance spectroscopy and time-resolved optical spectroscopy. The C14DPsaC-PS I and C14SPsaC-PS I complexes showed high levels of photoreduction of FA with g values of 2.045, 1. 944, and 1.852 after illumination at 15 K, but there was no evidence of reduced FB in the g = 2 region. The C51DPsaC-PS I and C51SPsaC-PS I complexes showed low levels of photoreduction of FB with g values of 2.067, 1.931, and 1.881 after illumination at 15 K, but there was no evidence of reduced FA in the g = 2 region. The presence of FB was inferred in C14DPsaC-PS I and C14SPsaC-PS I, and the presence of FA was inferred in C51DPsaC-PS I and C51SPsaC-PS I by magnetic interaction in the photoaccumulated spectra and by the equal spin concentration of the irreversible P700(+) cation generated by illumination at 77 K. Flash-induced optical absorbance changes at 298 K in the presence of a fast electron donor indicate that two electron acceptors function after FX in the four mutant PS I complexes at room temperature. These data suggest that a mixed-ligand [4Fe-4S] cluster is present in the mutant sites of C14X-PS I and C51X-PS I (where X = D or S), but that the proposed spin state of S = 3/2 renders the resonances undetectable in the g = 2 region. The C14APsaC-PS I, C51APsaC-PS I and C14D/C51DPsaC-PS I complexes show only the photoreduction of FX, consistent with the absence of PsaC. These results show that only those PsaC proteins that contain two [4Fe-4S] clusters are capable of assembling onto PS I cores in vivo. 相似文献
976.
摩擦诱发高铬铸铁相变的透射电镜研究 总被引:2,自引:0,他引:2
利用透射电子显微镜研究了高铬铸铁在摩擦过程中的显微组织变化。结果表明:奥氏体基体在摩擦应力的作用下发生相变。摩擦表面形成α‘M。次表层形成γ与α’M共存区;γ与.ε共存区;γ位错丛聚区。 相似文献
977.
978.
利用平板型热管纺丝装置对普通高速纺丝机进行技术改造,并一步法生产出充分结晶的PET纤维(FCY)。该纤维可直接用于织造,调节热管温度、热管安装位置可获得满足后道工序不同需要的FCY。 相似文献
979.
HPP-1型皮革加脂剂的研制和应用 总被引:1,自引:0,他引:1
本文概述了以磷酸化蓖麻油和羟化磷脂为基础的皮革加脂剂的研制,讨论了合成反应、产品配伍、应用试验等工艺过程。 相似文献
980.