One modified method of characteristics used to analyze the multiconductor transmission lines

1.INTRODUCTIONThe analysis of electromagnetic compatibility becomesmorei mportant in the analysis of the multiconductortransmissionlines(MTLs).It provides the effectivemethod for designing the MTLs.Several methodsbased on frequency domain and ti me domain tech-niques have beenrecently proposed[1,2].Thefrequen-cy method should performthe inverse Fourier trans-formation,so it is not more accurate than ti memethod to some degree.The method of characteris-ticsis based ontheti me domain met…     

局域网中基于ASP的办公信息的采集

办公事务中经常要求采集各种信息，传统的做法是印发数据表、填写数据表、再把数据录入到微机数据库保存和处理；现利用Windows98的PWS和Access数据库，以Weh浏览器和Web服务器交互访问的方式，将局域网上收集的信息直接保存到数据库中．     

太阳能采暖技术在宁夏南部地区的应用

宁夏回族自治区隆德县温堡乡中心小学位于１０５°０６′Ｅ、３５°３７′Ｎ，海拔高度为１８００ｍ。作为太阳能采暖技术的重点示范推广试点，介绍了采用太阳能采暖房的建筑及热工设计、测试分析与采暖效果以及经济分析等。同时探讨了室内不用辅助热源条件下适合于当地的太阳能采暖房。     

油库管理控制系统的集成化实现

介绍了计算机集成过程控制系统（ＣＩＩＰＳ）在没库储运生产中的应用，以及组成ＣＩＰＳ的局域网络，数据库和现场总线的结构，最后针对ＶｉｓｕａｌＢａｓｉｃ语言编制管理控制软件中的问题提出了解决方案。     

凹甲陆龟的泌尿生殖系统

凹甲陆龟的肾扁平，左右肾形状大小不一，呈荷兰豆荚形或块状方形．有特殊折叠，折起的形成可能与消化系统发达、遗传发育等因素有关．泄殖腔内有明显的环褶将肛道与尿、生殖道分开．附睾长而大，可能与精子的发育成熟和繁殖习性有关．     

我国城市绿地系统的规划与建设

城市绿地系统作为城市自然系统的主体,发挥着重要的生态功能.我国城市绿地建设普遍滞后,现在的城市绿地系统规划还存在不少问题,本文在分析绿地功能的基础上指出了在我国城市绿地系统规划与建设中所存在的几个主要问题,粗略地点明了解决这些问题的几点对策,尝试构建了使我国城市绿地系统规划顺利进行的内外条件.     

Recent Progress of Somatic Cell Nuclear Transfer in Pigs

Research in the field of somatic cell nuclear transfer (SCNT) and transgenic cloning in pigs has become a global hotspot，because porcine organs probably can be the first source of donor organs for human xenotransplantation. In recent years, though great progress has been made in porcine SCNT, the efficiency of nuclear transfer remains very low (<1%). Thus, it is necessary to improve the procedure of nuclear transfer and to investigate some basic problems further. Recent progress and the related problems of SCNT in pigs are reviewed and analyzed so as to offer some beneficial illumination to researchers.     

Improved dehydriding property of polyvinylpyrrolidone coated Mg-Ni hydrogen storage nano-composite prepared by hydriding combustion synthesis and wet mechanical milling

In this work, polyvinylpyrrolidone(PVP) coated Mg_(95)Ni_5 nano-composites were prepared by hydriding combustion synthesis(HCS) plus wet mechanical milling(WM) with tetrahydrofuran(THF) and donated as WM-x wt% PVP(x = 1, 3, 5 and 7) respectively. The phase compositions, microstructures and dehydriding property, as well as the co-effect of PVP and THF were investigated in detail. XRD results showed that the average crystal size of MgH_2 in the milled Mg_(95)Ni_5 decreased from 23 nm without PVP to 18 nm with 1 wt% PVP. The peak temperature of dehydrogenation of MgH_2 in the milled Mg_(95)Ni_5 decreased from 293.0 ℃ without THF to 250.4 ℃ with THF. The apparent activation energy for decomposition of MgH_2 in WM-7 wt% PVP was estimated to be 66.94 kJ/mol, which is 37.70 kJ/mol lower than that of milled Mg_(95)Ni_5 without THF and PVP. PVP and THF can facilitate the refinement of particle size during mechanical milling process. Attributed to small particle sizes and synergistic effect of PVP and THF, the composites exhibit markedly improved dehydriding properties.     

霍林河水库渗漏探测试验研究

高密度电法是常用的物探方法,在水库大坝探测方面也经常用到.文中介绍了高密度电法的原理和反演分析方法,采用高密度电法对霍林河水库大坝渗漏情况进行了探测试验,采用"单极-单极"阵列方式分别对大坝的4个断面进行了渗漏探测试验,并结合实测资料分析大坝渗漏原因.试验结果表明:高密度电法有效地探测了霍林河水库大坝渗漏情况,检验了防渗处理的效果,为大坝防渗加固提供了依据,也进一步验证了高密度电法在水库渗漏探测中具有较好的效果.     

基于改进Sobel算法的焊缝X射线图像气孔识别方法

提出一种具有自适应能力的焊缝X射线图像气孔检测方法.通过局部动态阈值分割法设计了多方向的焊缝X射线图像模板,采用Sobel算法对复杂背景下的焊缝进行边缘检测和区域标记,并在标记区域对原始图像x和y方向的灰度梯度进行分析,以增强小气孔和粘连气孔的识别能力.检测应用效果表明,所提出的方法具有良好的自适应能力且准确快速,能够有效地克服人工评片中产生的漏判与误判等缺点,并且能够存储和查询检测数据.