混合导体MAl0．97Zn0．03O3-y（M=Eu，Eu0.9Ca0.1）的合成与电性能

采用固相反应法合成了具有菱方钙钛矿结构氧化物MAl0．97Zn0．03O3-y（M=Eu，Eu0.9Ca0.1）。电导率随氧分压的变化关系表明，在600～1000℃范围内，MAl0．97Zn0．03O3-y和Eu0.9Ca0.1Al0.97Zn0.01O3-y都是一个氧离子与电子空穴的混合导体。双掺杂的Eu0.9Ca0.1Al0.97Zn0．03O3-y的氧离子电导率与单掺的MAl0．97Zn0．03O3-y相比，提高了约1.5个数量级，900℃时达到2S／m，约高于同温度下La0.9Sr0.1AlO3-y的电导率，活化能为1．25eV。本研究表明在EuAlO3体系可以通过优化掺杂离子的含量获得性能较好的氧离子导电材料。     

接触轨带电显示装置在城市轨道交通中的应用

介绍了城市轨道交通接触轨带电显示装置的应用,阐述了电压检测和隔离开关辅助触点两种研发方案,通过对比,采纳了电压检测方案来设置接触轨带电显示装置,提高了DC1500V接触轨系统的安全性.     

基于焦耳热分析的单轨交通导电轨防覆冰方案

针对跨座式单轨交通系统的特点,提出一种大电流防融冰方案。基于焦耳热效应建立了单轨交通系统的T型专用导电轨的热平衡方程,计算其临界防冰电流,并分析温度、风速等环境因素对防冰电流的影响。为验证其可行性,在ANSYS中建立T型导电轨模型并对其进行热分析,结果显示计算得到的临界防冰电流满足实际所需。     

THE EXPERIMENTAL RESEARCH ON CARDIOPLEGIC SOLU-TION CONTAINING SELENIUM AND MAGNESIUM AGAINST MYOCARDIAL ISCHEMIA REPERFUSION DAMAGE

MyocardiallschemiaandreperfusiondamagehavebeenstudiedfordecadesandmanyexperimentshavetestifiedthatOFRandoverloadofcalciumincellsarethemajorreasonsofthedamage.Seleniumisakindofactiveantioxidantwhereasmagnesiumisthenaturalantagonistofcalcium.SeleniumandmagnesiumcanreducethemyocardialdamagecausedbyOFRandoverloadofcalciumincells.Themodelbe.lugresearchedinthisarticleissetupbyisolatedperfusionofrat'shearts.ActivityofGPXandSODandquantityofMDA,selenium,magnesiumandcalciumintheliquidcollectedfrom…     

微量元素锂对蟾蜍离体脊髓反射性反应的影响

实验以蟾蜍离体脊髓为模型,研究锂对中枢神经系统的作用,发现锂能增强刺激背根在腹根诱发的反射性电位(DR-VRR),且抑制刺激背根在邻近背根诱发的背根电位(DR-DRP);锂对蟾蜍离体脊髓作用的阈浓度在4mmol/L以下。用蔗糖间隙法记录脊髓背、腹根极化水平,发现锂能引起腹根去极化,且作用不被Mg~(++)阻断;锂也能引起背根去极化,但去极化能被Mg~(++)阻断;锂还能抑制背、腹根上的强直后超极化。锂作用的基本机理可能与Na~+-K~+泵的转运有关。     

A Probability Model of Bicycles Crossing Vehicle-bicycle Separation Lines

Vehicle-bicycle separation lines are frequently used to isolate motor vehicles from bicycles on China's urban roads. Conflict between motor vehicles and bicycles exists in these road sections. It is regularly caused by bicycles crossing the vehicle-bicycle separation line onto the motor vehicle lane. Thus, it is imperative to research the probability of crossing travel of bicycles. First, two presumptions for bicycles to cross travel are stated. One is that bicycles need to cross the traffic marking; the other is that the space among the adjacent motor vehicle flows is available for bicycles to cross. With this observation, the probability of conflicts between motor vehicles and bicycles can be obtained as a product of their probabilities. Based on this probability, the result was summarized as follows: the probability for bicycles crossing the traffic marking obeys a negative exponential distribution, which is derived. The result was shown by theoretical analysis and was compared to actual survey data. The available probability for bicycles entering into motor vehicle flow was found by the use of a traffic survey. Therefore, a probability function was proposed with different spaces that led to a probability model for vehicle-bicycle conflicts. At last, using the survey data, the probability model proved to be correct.     

船用全桥隔离DC/DC变换器的建模与控制

针对大功率脉冲负载在船舶领域中的应用为背景,对其中全桥隔离DC/DC变换器展开研究。本文基于最小回流功率的双重移相控制策略,通过分析双重移相控制下的软开关条件及其功率传输特性,建立了其动态小信号模型。最后通过Matlab/Simulink仿真实验对控制策略进行验证,实验结果表明了采用基于最小回流功率控制对提高变换器效率的有效性。     

遇孤石钻孔灌注桩基础施工方法

该文以深圳市香莲立交桥桩基础工程为例子,通过叙述该桩基础工程遇到孤石的具体施工方法,成桩的质量情况和工艺选取,技术改革与效益,提出桩基础施工一旦遇到孤石时应注意的若干问题。     

大型深水导管架井口导向同心度的计算方法

描述了一种大型导管架井口同心度的计算方法，用最小二乘法将各层井口中心点坐标拟合成一条空间直线，再计算各个井口导向中心到拟合直线的距离，从而准确地判断井口是否偏离最佳拟合直线。利用VBA编程软件，可以非常快速地计算出结果，大大提高了效率。     

集电靴与接触轨集电系统研究综述

阐述集电靴与接触轨的结构改进、运行现状和标准建设,以及集电靴、接触轨和靴轨接口的测试与仿真技术,并展望集电靴与接触轨集电系统的发展方向。现有集电靴种类较多,尚未形成通用的力学模型,需进一步构建集电靴动态性能试验台获取其关键力学参数。集电靴与接触轨的动态测量装置尚需进一步标定,以确保测试数据的准确性。集电靴与接触轨的动态仿真尚需实际测量数据验证其有效性。集电靴与接触轨系统接口的标准尚需进一步完善。