A Chamber for X-Ray Diffractometry of Gas Hydrates Samples for Pressures of Up to 700 atm

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.     

Magnetotransport properties of type II heterojunctions based on GaInAsSb/InAs and GaInAsSb/GaSb

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 Ga_1?x In_xAs_ySb_1?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.     

Strains of Synechocystis sp. PCC 6803 with altered PsaC. II. EPR and optical spectroscopic properties of FA and FB in aspartate, serine, and alanine replacements of cysteines 14 and 51

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.     

摩擦诱发高铬铸铁相变的透射电镜研究

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。     

离子交换法合成三氨基胍叠氮酸盐

三氨基胍叠氮酸（ＴＡＺ）分子中的含氮量高达８５．７％，燃烧分解时不仅－Ｎ３可释放３６７ｋＪ／ｍｏｌ的键能，而且放出大量的氮气，是一个提高比冲，降低燃烧温度的理想的推进剂两组分之一。     

旋风燃烧器冷态模型内颗粒运动轨迹计算

在冷态模型流场内，考虑气流对粉煤颗粒的气动阻力，建立其运动微分方程式。通过计算，得到九种粒径的颗粒在流场中的运动轨迹、停留时间、着膜位置和气－固相相对速度与该燃烧器几何参数和气动参数的关系，为燃烧器的深入研究提出了建议。     

利用热管纺丝技术一步法生产FCY

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。     

HPP－1型皮革加脂剂的研制和应用

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。     

Monitoring the technical state of digital radioelectronic apparatus with the aid of signature analysis

This article presents the technical characteristics and a comparative analysis of the most widely used types of signature analyzers. It formulates the requirements on radioelectronic apparatus the diagnosis of which is planned with the aid of signature analyzers. Trends in the development of diagnostic apparatus using the method of signature analysis are determined.Translated from Izmeritel'naya Tekhnika, No. 7, pp. 50–54, July, 1993.