基于子模型法的330 kV线路绝缘子串电压分布计算

采用子模型法计算了330 kV输电线路绝缘子串的电压分布,计算中考虑了铁塔的具体结构及三相电压之间的相互影响;通过与现场实测数据的比较,证实了该算法的有效性,该算法所得结果可用于研究330kV线路工频电压下绝缘子串闪络原因和闪络机理,以及用于制定符合线路安全运行的防治措施.     

多介质空间分异模型的研究进展

鉴于多介质空间分异模型能够更综合、更细致、更真实地描述化合物在实际环境中的分配、传递与转化过程,是评价化合物环境行为的一种有效工具,在介绍多介质模型分类情况的基础上,综述空间分异模型近十年的发展与应用情况,并对其应用前景和发展趋势作了展望.     

平行轴外啮合齿轮同向传动的可行性研究

传统的平行轴外啮合斜齿轮在啮合传动过程中,两齿轮的转动方向是相反的.通过对渐开线斜齿轮齿廓啮合特点的分析,表明平行轴外啮合斜齿轮可实现同向传动.并建立实现同向传动齿轮的正确啮合及连续传动条件.     

多媒体在高等数学教学中的作用探讨

多媒体在高等数学教学中的作用一直以来倍受争议。本文从学习兴趣、数学美、数学建模以及留有思维空间等几个方面对多媒体在高等数学教学中的作用做一个初步的探讨。     

工程车辆等比三段式液压机械的复合传动

针对目前工程车辆液力机械传动换挡过程中存在的传动比不连续的问题,提出了一种新型的等比三段式液压机械复合传动系的方案,并对其速度特性、动力性、经济性等进行了分析。对比分析液压机械复合传动与液力机械传动的结果表明,液压机械复合传动系统能够自动调节变量泵倾角,实现发动机与动态负载的匹配,传动系统的经济性和动力性均得到了改善,动力特性曲线光滑、平缓,对于改进工程车辆传动系的性能具有重要的现实意义。     

GPS定位系统的研究与产品试制

该文介绍了一个GPS定位系统的研究与产品试制，其中包括三部分内容，首先介绍了以MCU为核心的手持式客户端定位子系统，然后介绍了用GPRS传输定位数据的方法，最后介绍了在服务器端如何处理显示定位信息。整个系统通过调试，最终到达了定位信息在客户端的简单显示和在服务器端与特定地图结合的复杂显示的目的。     

基于FPGA的码分多址基带通信系统

在介绍码分多址(CDMA)通信系统原理的基础上,提出了一种基于FPGA的CDMA基带传输系统的设计。该系统采用EDA技术中自顶向下的设计方法,将CDMA基带通信系统中主要硬件的功能通过编程方式制作在FP-GA芯片上。文中详细地介绍了系统中各个主要模块的设计思路、工作原理以及仿真结果。该设计简化了系统的外围电路,节约了成本,增大了系统的通信容量,提高了系统抗干扰能力。     

摆动活齿传动弹流润滑的数值计算及分析

应用弹性流体动力润滑理论，建立了摆动活齿传动弹流润滑的基本方程。提出了摆动活齿传动弹流润滑问题的数值求解方法。计算实例表明：摆动活齿传动弹流润滑计算公式和数值计算方法是正确有效的；润滑油膜厚度随载荷增大而减小，随综合曲率半径增大而增大，随卷吸速度增大而增大；活齿与内齿圈啮合副油膜厚度的变化规律是：前半个啮合周期内油膜由厚变薄，后半个啮合周期内油膜由薄变厚，在拐点附近油膜最薄。在拐点附近易产生疲劳点蚀和磨损。弹流润滑研究的结果为摆动活齿传动的摩擦学设计提供了理论依据。     

Assurance of uniformity of measurements of spectral and dispersion characteristics in fiber-optic information transmission systems with wavelength-division multiplexing

The state and problems involved in achieving the uniformity of measurements in the field of fiber-optic information transmission systems and their components are considered. Possible approaches to the solution of these problems and the basic methods and techniques that have been developed in Russia up to this point are analyzed. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 30–34, May, 2006.     

Quantitative characterization of nanoprecipitates in irradiated low-alloy steels: advances in the application of FEG-STEM quantitative microanalysis to real materials

The characterization of the solute-enriched features (clusters or nanoprecipitates in irradiated low-alloy steels) requires extremely high spatial and elemental resolution, previously necessitating analysis using atom probe field-ion microscopy. In this investigation, field-emission gun-scanning transmission electron microscope (FEG-STEM) quantitative energy dispersive X-ray (EDX) microanalysis (spectrum imaging) has been applied to the characterization of the irradiation-induced nanoprecipitates in a low-alloy forging steel. Refinements in the EDX data have been possible via the application of multivariate statistical analysis (MSA) to the spectrum images, resulting in significantly reduced noise in the images. Most importantly, MSA permitted the clear identification of other elements in these Ni-enriched nanoprecipitates—including Mn and Cu. The processed X-ray spectrum images also provided direct evidence of the preferential formation of these irradiation-induced features along pre-existing dislocations within the steel, as well as the formation of intragranular nanoprecipitates. This research has provided the first direct X-ray spectrum images of irradiation-induced nanoprecipitates in high Ni A508 Gr4N forging steel, and has demonstrated the significant improvements attainable though the application of MSA techniques to the spectrum images. These results independently confirmed the analyses of the Ni-enriched nanoprecipitates previously conducted by 3D-APFIM, with the performance of the FEG-STEM/EDX technique shown to be comparable to that of the 3D-APFIM technique.