摘要： The application of liquid chromatography with electrochemical detection for the selective analysis of organics in complex mixtures is decribed. Experimental conditions are given for the quantification of phenols, aromatic amines and certain heterocyclic bases related to piperidine and pyrrolidine, after preliminary separation into acidic, basic and neutral fractions. The technique is applied to the analysis of oil shale retort waters.

关键词： 内燃牵引   进口   电力牵引   传动   电气化铁路   电气化铁道   铁路牵引动力   基本扣除系数   进程   美国   美利坚合众国   北美洲   ND  

摘要： 世界上不少国家,都把铁路电气化作为国策,并优先用在客、货运输量大的繁忙干线上。例如苏联提出:“铁路过渡到电力牵引,是技术进步的最主要的方向”。苏联到1985年,电气化铁路里程将超过5万公里,占全国铁路网总长度的34.5%,承担着60%的运输工作量。日本到1976年,已取消了蒸汽牵引,到1982年电气化铁路里程已达8700 km,电化率达40.6%电力率引承担货运量的83.4%,客运量的85.4%。印度在1973年后遇到了能源危机,石油涨价,在进口原油使外汇紧张的情况下,认识到必需改用电力牵引,以便使用丰富的水力和热电资源。计划到1990年将有一万公里电气化铁路。西德从五十年代开始进行牵引动力改革,到目前电化率已达85%。综观国外情况,一些主要采用电气化的国家,多是用三分之一的电气化铁路承担着四分之三以上的运量。

关键词： 进口   电气化铁路   电气化铁道   内燃牵引   ND5   电力牵引   传动   列车对数   电阻制动装置   牵引定数   列车平均牵引量   铁路电气化   机车车辆   NDS   牵引重量   电化率   进程   东风   牵引动力   美国   美利坚合众国   北美洲  

摘要： “电力牵引为主,电力机车担负运量的比重要逐步增加”一这是我国铁路牵引动力技术政策的既定方针。本文通过对国产电力机车与美国进口ND型内燃机车的技术经济比选,进一步阐明了电力牵引的优越性和加速繁忙干线电气化进程的必要性。

关键词： 铁路运输能力   投产运营   蒸汽牵引   铁路电气化   新建铁路   电气化改造   内燃牵引   电气改造   勘测设计   营业里程  

摘要： <正>在加强线路运输能力的各种措施中，铁路电气化改造是一种投资少、见效快的有效措施。特别是在运量大的线路上，电气化改造的经济效益尤为显著。据有关方面统计，修建一公里新线，大约需要200～300万元，从勘测设计到投产运营往往要十年之久；而电气改造的投资只占新建铁路的1/5～1/8（单线40～50万元，双线70～80万元）。只要土建改造予先完成或改造工程量不大，从设计到投产运营有2年左右的时间即可。而提高的运输能力较蒸汽牵引可高2～4倍，较内燃牵引可高1倍。每万吨公里的投资费用，

摘要： Several aims to be met in the design of an electroanalytical system to be used for the continuous analysis of dissolved species in aqueous process streams are discussed. Relatively few of the many electroanalytical techniques now available are capable of adaptation to the stringent requirements but of those that are, the most widely used are direct potentiometry, conductivity measurement and the simplest forms of voltammetry. The modification of each of these 3 techniques to process stream monitoring is described. Among the species and parameters commonly measured are pH, dissolved ammonia, Cl and O2 redox potential, conductivity and concentrations of Na, nitrate and sulfide ions. Frequently, it is more important for the system to monitor changes in these parameters than to measure actual concentrations.

摘要： The application of electrochemical techniques to the study of rapid photolytic processes in solution has been limited previously by serious electronic disturbances caused by flash photolytic instrumentation, by a lack of theory relating second-order photolytic rate steps to observed electrolysis currents, and by the lack of a quantitative evaluation of the effects of electrochemical measurements of nonhomogeneous solutions produced by flash irradiation. The work reported here attempts to examine and minimize these limitations. The electrochemical monitoring technique utilized was potentiostatic analysis at a hanging mercury drop electrode located in the flash-photolyzed solution. Instrumental improvements have been made extending the time resolution by a factor of 20 over that previously attained;theoretical expressions correlating second-order photolytic rate processes with current-time behavior at a stationary electrode have been described and evaluated;and a theoretical and experimental evaluation of solution nonhomogeneity and its effects in these photo-electrochemical experiments has been presented. Kinetic data for the dimerization of the ketyl radical and ketyl radical anion produced in the flash photolysis of benzophenone are reported with time resolution as short as 50_µsec. In addition, derived relationships correlating transmittance characteristics with electrochemical response have been evaluated experimentally. © 1968, American Chemical Society. All rights reserved.