天然调味料──酵母抽提物的研究进展

着重论述了酵母抽提物的特性、在食品中的应用前景、制造方法、工业化生产中存在的问题及其解决方法，并对酵母抽提物的发展方向作一展望。     

Novel polymeric aromatic lithium sulfonylimides as salts for polymer electrolytes

Three new polymeric aromatic lithium sulfonylimides were used as salts in high molecular weight poly(ethylene oxide) (PEO) electrolytes. Their conductivity and electrochemical stability behaviors were investigated. The electrolytes with lithium poly[4,4′‐(hexafluoroisopropylidene)diphenoxy]sulfonylimide (LiPHFIPSI) showed a better conductive performance compared with the other two lithium salts. The best conductivity was obtained for PEO/LiPHFIPSI EO/Li = 16 (1.90 × 10^?4 S/cm at 60°C). Thermal analysis indicated that the salts effectively decreased the crystallinity of PEO. Moreover, the electrolytes also had good electrochemical stability and their oxidative potential was to 5.5 V versus Li/Li⁺. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1802–1805, 2002     

被Kerr介质包围的J—C模型中光场位相特性

本文应用Pegg-Barnett位相理论讨论了被Kerr介质包围的J-C模型中光场的位相性质。     

Dyspnea resulting from phrenic nerve paralysis after interscalene brachial plexus block in an obese male--a case report

While current psychiatric taxonomies recognise a classification of amphetamine dependence, derived from the notion of an alcohol dependence syndrome, little research has validated that such a condition exists for this drug. Current amphetamine users (N = 331), were interviewed using the World Health Organization operationalisation of DSM-III-R substance dependence criteria, and a measure of the psychological components of dependence. Structural analyses indicated that a unidimensional dependence syndrome as assessed by DSM-III-R and DSM-IV criteria exists for amphetamine, and that physiological, psychological and behavioural indicators were all important in accounting for the variance in responses. It was demonstrated that the concept of a dependence syndrome is applicable to amphetamine, and that the inclusion of the amphetamine dependence syndrome in DSM-III-R and DSM-IV is valid.     

套管动力钳转矩监测系统

下套管作业时，套管螺纹联接质量的好坏直接影响着油井寿命，因此有必要研制一种套管动力钳转矩监测系统。以目前国内常用的ＴＱ－２０型套管动力钳为例，介绍了一种与之相配套的套管钳转矩监测系统的功能特点，测试原理，结构设计，并对实测各类紧扣曲线进行了分析。该系统采用主从机结构，主机为工业控制微机，从机为单片机系统，主从机采用远距离通信传输，大大地改善了工业控制微机的工况条件。该系统实现无人监控、自动记录、绘     

特征线法分析长距离输油管道的流动瞬变过程

本文建立了基于特征线方法求充动瞬变过程的数值模型，编制了针对长距离输油管道流动瞬变过程的分析软件。在数值处理上，Ｄａｒｃｙ＝Ｗｅｉｓｂａｃｈ摩擦力项用二阶精度格式来近似，因此保证了高粘度流体在流动瞬变过程分析时的计算稳定性和精确度。模型考虑了埋管地形对沿线瞬变压力的影响，当某一泵站发生水击后其它站的反应同其上控程序确定。应用该软件，分析模拟了某一长距离输油管道在中间泵站停电或末站瞬时关阀情况下的流     

pH/ORP测量应用中的问题解析

1 pH／ORP测量系统的组成 一个完整的测量系统包括pH／ORP电极、保护测量电极的安装支架和测量变送器。测量电极和安装支架的正确选择是组成一个良好的、功能完备的测量系统的必要前提。     

上海市吴淞工业区大气PM2.5水溶成分的元素分析及细胞毒性研究

通过ICP-MS测定了上海市吴淞地区大气PM2.5水溶成分金属元素含量,通过四唑盐(MTT)测定细胞存活率,通过超氧化歧化酶(SOD)和丙二醛(MDA)两个指标测定细胞氧化损伤,琼脂糖凝胶电泳测定细胞内DNA损伤,流式细胞仪(Flow cytometry)检测细胞凋亡和周期等实验研究了大气PM2.5水溶成分的细胞毒性.实验结果表明:PM2.5可溶成分中Zn元素含量最高,PM2.5在一定浓度范围内能导致细胞死亡,引起细胞的氧化损伤,影响DNA的复制,阻碍细胞增殖,但没有诱导细胞凋亡.PM2.5中可溶金属离子对细胞毒性表现为联合作用.     

葛洲坝电站2号水轮机转轮室中环修复

针对葛洲坝电站2号机组运行中出现转轮室中环损坏的现象,设计制造出转轮室现场机加工的大型专用机床,在修复改造过程中,解决了一系列技术难题,改造后技术指标均达到理想水平,为电站机组现场修复技术积累了宝贵经验.     

Ab initio calculations on the mechanism of isobutane and 2-butene alkylation reaction catalyzed by hydrofluoric acid

Ab initio method was employed to determine the mechanism of alkylation reaction of 2-butene with isobutane. The results indicated that 2-butene is rapidly protonated to form sec-butyl carbonium ion, which then reacts with isobutane to form tert-butyl carbonium ion. The resulting carbonium ion is then deprotonated to form isobutene that reacts rapidly with tert-butyl carbonium ion to form trimethylpentane (TMP) carbonium ion. Finally, the TMP⁺ carbonium ion is converted to TMP via the hydride transfer process. The transition states of the interactions were obtained by using the SCAN method (a calculation key word for potential energy surface) first and then the intrinsic reaction coordinates were traced using the Gaussian program. In addition, the energy changes and geometric parameters of the interactions were analyzed. The computed results indicated that the energy barriers are close to or less than zero for the interaction of isobutane with protonated 2-butene or for the interaction of tert-butyl carbonium ion with isobutene, suggesting rapid reaction steps of the carbonium ions. The 2,2,3-TMP is kinetically controlled, while the formation of 2,2,4-TMP is controlled by reaction equilibrium. The calculated results were in good agreement with the experimental results.