电厂电气运行中常见故障分析及其应对措施探讨

为了保证电厂的生产效率,必须要分析电气的运行特征,确定电气故障发生的原因,综合考虑多方面因素,选择切实可行的措施解决问题。简要分析了电厂电气运行常见故障发生原因,并提出了相应的解决措施。     

基于自主版式技术的结构化工卡系统设计与实现

为了解决传统纸制介质信息存储困难、维护效率低下等问题,在研究S1000D规范下的交互式电子技术手册(IETM)的基础上,文中提出将自主版式技术应用到航空维修工卡系统的设计上,从而实现结构化工卡数据模型的存储与显示。     

基于细胞阻抗传感器的腹泻性毒素检测系统设计与实现

针对海洋水产品腹泻性毒素检测问题,设计了一种新型的基于细胞阻抗传感器(ECIS)的毒素快速检测分析系统。相对于传统的毒素检测方法,该系统具有操作简便,高一致性和高通量等特点。介绍了系统的硬件设计和软件设计,通过对系统整体性能测试以及使用神经母细胞瘤细胞(Neuro-2a)对腹泻性贝毒(DSP)大田软海绵酸(OA)进行毒性检测实验,用以验证系统平台的可行性。实验结果表明,基于细胞传感器的海洋水产品腹泻性毒性检测系统具备快速,长期,无损和高通量测量的特点,为腹泻性毒素检测提供了新的平台。     

Correlation of reactivity and electrical resistivity of coke

A correlation between the reactivity and electrical resistivity of a series of cokes was determined using cokes prepared from blends of medium- and high-volatile coals. After correcting for the ash yield of the coke and the density of the resistivity specimen, a statistically significant relation between reactivity and resistivity was established. As the resistivity test requires much less time to perform than the reactivity test, it can be considered as an alternative approach to reactivity testing currently performed for quality control purposes.     

Microstructures and Dielectric Properties of Pure and Doped KNbO3 Ceramics

Regions consisting of grains of pronounced cubic develpment exist in pure KNbO₃ ceramics which exhibit a temperature dependence of dielectric constant very similar to that of KNbO₃ crystals. KNbO₃ ceramics doped with GeO₂-K₂O additives have small grains, semiconducting resistance, and a different curve of dielectric constant versus temperature. As the average grain size decreases, the shape of the curve differs increasingly from that of KNbO₃ crystals.     

Surface performance of workpieces processed by electrical discharge machining in gas

The surface performance of workpieces processed by electrical discharge machining in gas(dry EDM)was studied in this paper.Firstly,the composition,micro hardness and recast layer of electrical discharge machined(EDMed)surface of 45 carbon steels in air were investigated through different test analysis methods.The results show that the workpiece surface EDMed in air contains a certain quantity of oxide,and oxidation occurs on the workpiece surface.Compared with the surface of workpieces processed in kerosene,fewer cracks exist on the dry EDMed workpiece surface,and the surface recast layer is thinner than that obtained by conventional EDM.The micro hardness of workpieces machined by dry EDM method is lower than that machined in kerosene,and higher than that of the matrix.In addition,experiments were conducted on the surface wear resistance of workpieces processed in air and kerosene using copper electrode and titanium alloy electrode.The results indicate that the surface wear resistance of workpieces processed in air can be improved,and it is related with tool material and dielectric.     

Electroless nickel plating on the surface of carbon fibers

The electroless nickel plating on the surface of carbon fibers was prepared by pretreating the carbon fibers in order to increase their conductivity,and consequently enhance the EMI shielding effectiveness of the composites.The relationship between the performance of depositing coat and pH value,temperature,reaction time and the way of agitation was studied.Results show that the depositing quality is stable under pH between 4.5 and 5.0,temperature between 75 ℃ and 85 ℃,reaction time for 10 min and air agitation.The uniform and compact nickel layer deposited on carbon fibers was proved by XRD and SEM,and the electrical resistivity of carbon fibers with nickel coating was tested.Results indicate that the electrical resistivity of carbon fibers with electroless nickel plating is decreased by an order of magnitude compared with that of carbon fibers.It means that nickel coating can greatly improve the electromagnetic interference shielding properties of carbon fibers.     

无机纳米-聚酰亚胺复合薄膜介电性研究

测试了纳米Al2O3-聚酰亚胺(PI)复合薄膜和纳米SiO2-聚酰亚胺复合薄膜的介电常数、介质损耗角正切和电导电流特性.结果表明,随着无机物含量的增加,两种复合薄膜的相对介电常数和介质损耗角正切增大,电老化阈值减小;无机物含量相同时,Al2O3-聚酰亚胺复合薄膜的相对介电常数和介质损耗角正切比SiO2-聚酰亚胺复合薄膜大,电导电流大,电老化阈值小.     

电热爆炸喷涂法制备TiC涂层的特性分析

采用电热爆炸定向喷涂工艺在镍合金基体上制备TiC涂层,借助光学显微镜、显微硬度计分别对涂层显微组织、涂层硬度进行了测试。利用图像分析软件对涂层的晶粒尺寸进行了测量。结果表明,电热爆炸定向喷涂制备的涂层组织晶粒明显细化,涂层组织为典型的快速凝固组织。涂层组织比原始喷涂材料镍合金组织细小、均匀;TiC涂层中大晶粒所占涂层面积为93.6%,小晶粒所占面积为6.4%;大晶粒的弦长平均值为500 nm左右,小晶粒的弦长平均值为81 nm左右;表层有些孔隙;涂层硬度均明显高于基体材料镍合金的硬度,其最高硬度达到了582.5 HV。     

海洋废弃平台桩基拆除绳锯机控制系统研发

海洋废弃平台拆除过程中需要切断桩基,水下绳锯机是一种安全环保的桩基切割工具．介绍了绳锯机的工作原理,提出了控制系统的总体结构,设计了控制系统的硬件和软件,实验表明此控制系统能够使绳锯机安全、稳定的工作．