合金元素对钢筋耐腐蚀性能和机械性能的影响

通过正交试验，研究了成分为(％)：0．10～0．12C，0～0．78Cr，0．32～0．67Ni，0～0．52Mo，0～0．06V，0．30～0．36Cu低碳高强度钢筋的耐蚀性和力学性能。结果表明，Cr能显著提高钢筋的耐氯盐腐蚀性，含0．53％～0．78％Cr、0．32％～0．35％Ni的钢筋具有良好的耐蚀性；加Mo，V可显著提高钢筋的强度。     

基于广域测量的系统电压崩溃点预测

许多文章对电力系统电压崩溃问题进行了研究，其中潮流分析的方法是最常见的，大都是以Q—V曲线为基础。近些年，越来越多的人认识到电力系统电压稳定问题是一个动态问题，而电压崩溃点是可以提前预知的。随着GPS(全球定位系统)和PMU(向量测量单元)的进一步应用，广域测量技术应用范围越来越广，其用在电力系统电压崩溃点的预测也将成为必然。本文以广域测量技术为辅助手段，根据功率边缘的概念，使用电压崩溃预洲器来预洲系统中电压崩溃点的位置。     

A comparative study of research performance in computer science

The paper compares the research performance in computer science of four major Western countries, India and China, based on the data abstracted from INSPEC database during the period 1993–2002. A total of 9,632 computer science papers recorded in INSPEC database were used for the comparison. The findings indicate that, on the one hand, the number of papers produced in China has considerably increased in the past few years. Particularly, in recent years, China occupies a remarkable high position in terms of counts of papers indexed by the INSPEC database. On the other hand, Chinese scientists preferred to publish in domestic journals and proceedings and shares of SCI-papers to the total journal papers for China have still remained the lowest. This indicates that the research activities of Chinese scientists in computer science are still rather “local” and suffer from a low international visibility. Various scientometric indicators, such as Normalized Impact Factor, ratio of papers in high quality journals are further adopted to analyze research performance and diverse finding are obtained. Nevertheless, for these surrogate indicators, China has optimistically achieved great progress, characterized with “low level of beginning and high speed of developing”. The policy implication of the findings lies in that China, as well as other less developed countries in science, can earn relative competitive advantages in some new emerging or younger disciplines such as computer science by properly using catch-up strategy. This revised version was published online in June 2006 with corrections to the Cover Date.     

世界航空钛市场现状及发展趋势

介绍了美国、俄罗斯、欧洲及亚洲的航空钛市场现状,分析了民用客机、军用飞机及航空发动机对钛材的需求形势。目前,世界航空钛市场处于复苏阶段,波音与空客两大公司的订单开始大幅增加。世界航空钛市场中长期前景看好,用钛量将持续攀升。预计到2015年,世界航空用钛材交货量将达到12.5万t。     

高碳铬铁降碳探讨

介绍了在12 5MVA电炉上进行高碳铬铁降碳的试验情况 ,分析了影响FeCr67C6 0合金含碳量的因素 ,从理论和实践两方面阐述了降碳措施     

Purification and characterization of maize starch synthase I and its truncated forms

A number of imidazole-based compounds were tested for their utility as (1)H NMR molecular probes of intracellular pH. Imidazole, previously found useful as a probe of erythrocyte pH, reported a pH in perfused canine glioma cells that was more than 1 pH unit lower than that reported by inorganic phosphate, consistent with the known lysosomal compartmentation of the molecule. Imidazole acetate, also proposed as an NMR probe of cellular pH, was found not to enter the cells of this study. Histidine was found to be readily taken up by cells and reported a pH consistent with that reported by inorganic phosphate. Using the chemical shift of the histidine H2 proton in cells incubated with 10 mM histidine, cellular pH measurements could be obtained in less than 1 s. This compares quite favorably with the measurement time, typically several minutes, needed to assess in vivo pH by (31)P NMR. The use of histidine as a probe of pH is demonstrated in perfused canine and rat glioma cells subjected to ischemia or to low extracellular pH.     

连续五年保持高产的低渗透油藏实例研究

针对怀俄明西南Wamsutter油田的阿尔蒙特和路易斯低渗透砂岩油藏, 组织了一支科研小组.该小组于1998年对油藏进行研究,以解决生产井产量低的问题.研究小组面临的挑战包括:①确定生产井是否已达到最高产量;②确定一个基准值,以衡量各种改进措施是否成功;③找出低产的主要原因;④应用新技术和新工艺解决低产问题;⑤采取增产措施,提高生产井的净现值;⑥将完井过程中各种措施的效果记录下来.开始时,将90天的平均产量作为基准值,结果5年内超过基准值100%,生产井的平均产量也提高了50%以上.     

纳滤回收染料废水中染料的实验研究

以含盐染料废水为研究对象,应用商业化的卷式膜组件,研究了纳滤膜对染料和盐的截留特性．实验结果表明,纳滤膜对染料的截留率高达99％以上．当染料分子量高于膜截留分子量时,染料初始浓度和染料品种对染料截留率的影响甚小,盐浓度对染料截留也无明显影响,但对NaCl截留率影响显著．随料液中NaCl浓度的增加,盐截留率快速下降,当盐浓度达到3．5％时,NaCl的截留率低于25％．纳滤膜对染料的高截留率和对NaCl的低截留率,使得应用纳滤技术从含盐染料废水中回收染料具有较好的经济性和可行性．     

Decentralised adaptive control for a class of stochastic switched interconnected nonlinear systems

In this paper, we focus on the problem of adaptive stabilisation for a class of interconnected uncertain switched stochastic nonlinear systems. Classical adaptive and backstepping technique are employed for control synthesis. Instead of estimating the switching parameters directly, we design the adaptive controller based on the estimations of bounds on switching time-varying parameters. A smooth function is introduced to deal with the difficulties caused by unknown interactions and tuning function approach is used to circumvent the overparameter problem. It is shown that under the action of the proposed controller all the signals of the overall closed-loop systems are globally uniformly bounded in probability under arbitrary switching. Simulation results are presented to illustrate the effectiveness of the proposed approach.