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871.
本文定量分析计算三相交流输电线路正常运行工频电、磁场对周围环境影响,以及产生电晕时对无线电接收的干扰影响。并分析在输电线路短路状态下其电磁场对周围环境的影响。 相似文献
872.
873.
Jaffee Sara R.; Caspi Avshalom; Moffitt Terrie E.; Taylor Alan 《Canadian Metallurgical Quarterly》2004,113(1):44
The well-documented finding that child physical maltreatment predicts later antisocial behavior has at least 2 explanations: (a) Physical maltreatment causes antisocial behavior, and (b) genetic factors transmitted from parents to children influence the likelihood that parents will be abusive and that children will engage in antisocial behavior. The authors tested these hypotheses in the representative Environmental-Risk cohort of 1,116 twin pairs and their families, who were assessed when the twins were 5 and 7 years old. Mothers reported on children's experience of physical maltreatment, and mothers and teachers reported on children's antisocial behavior. The findings support the hypothesis that physical maltreatment plays a causal role in the development of children's antisocial behavior and that preventing maltreatment can prevent its violent sequelae. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
874.
875.
基于RS-485总线的调度模拟盘控制系统 总被引:1,自引:0,他引:1
针对以往调度模拟盘控制系统采用非智能化功能单元、并行传输方式所带来的种种弊端,例如:易受到干扰、接线复杂、不能实现显示单元自检及动态潮流方向显示等,本文提出一种基于RS-485总线的解决方案。 相似文献
876.
为减少图像传输的数据量,满足信道带宽的要求,在图像发送端以块为单位对图像进行划分,利用离散余弦变换(DCT),按照一定的规则主动丢弃部分块的低频分量,而在图像接收端通过图像重建技术对丢弃的图像数据进行恢复,从而再现原图像。实验结果表明这种数字图像传输技术改善了DCT图像质量。 相似文献
877.
Optimization of photo‐aligned ferroelectric liquid‐crystal display under passively addressed driving
D. D. Huang E. P. Pozhidaev V. G. Chigrinov H. L. Cheung H. S. Kwok 《Journal of the Society for Information Display》2004,12(4):455-459
Abstract— A ferroelectric liquid‐crystal (FLC) passively addressed 64 × 64 display based on the photo‐alignment technique has been developed. The display matrix has dimensions of 33 × 33 mm2, and the FLC layer thickness is about 5 μm. Asymmetric boundary conditions, when only one of ITO surfaces of the display matrix is covered with the photo‐aligning layer while another one is not, have been used for providing both high contrast ratio and steady multiplex operation. The electro‐optical performance of the 5‐μm FLC display is presented, including bistable switching in static operation, optimization in multiplexing operation, and gray‐scale generation. 相似文献
878.
Y. Z. Huang S. Lozano-Perez R. M. Langford J. M. Titchmarsh & M. L. Jenkins 《Journal of microscopy》2002,207(2):129-136
The preparation of transmission electron microscope (TEM) thin foil specimens from metal alloys containing cracks is usually thwarted by the difficulty in preventing preferential erosion of material along the flanks and at the tips of cracks. Recent developments in focused ion beam (FIB) micromachining methods have the potential to overcome this inherent problem. In this article we describe the development of new procedures, one using FIB alone and the other using a combination of FIB with more conventional ion milling to generate TEM specimens that largely retain the microstructural information at stress corrosion cracks in austentic alloys. Examples of corrosion product phase identification and interfacial segregation are included to verify that detailed information is not destroyed by ion bombardment during specimen preparation. 相似文献
879.
880.
Suga M Nishiyama H Konyuba Y Iwamatsu S Watanabe Y Yoshiura C Ueda T Sato C 《Ultramicroscopy》2011,111(12):1650-1658
Although conventional electron microscopy (EM) requires samples to be in vacuum, most chemical and physical reactions occur in liquid or gas. The Atmospheric Scanning Electron Microscope (ASEM) can observe dynamic phenomena in liquid or gas under atmospheric pressure in real time. An electron-permeable window made of pressure-resistant 100 nm-thick silicon nitride (SiN) film, set into the bottom of the open ASEM sample dish, allows an electron beam to be projected from underneath the sample. A detector positioned below captures backscattered electrons. Using the ASEM, we observed the radiation-induced self-organization process of particles, as well as phenomena accompanying volume change, including evaporation-induced crystallization. Using the electrochemical ASEM dish, we observed tree-like electrochemical depositions on the cathode. In silver nitrate solution, we observed silver depositions near the cathode forming incidental internal voids. The heated ASEM dish allowed observation of patterns of contrast in melting and solidifying solder. Finally, to demonstrate its applicability for monitoring and control of industrial processes, silver paste and solder paste were examined at high throughput. High resolution, imaging speed, flexibility, adaptability, and ease of use facilitate the observation of previously difficult-to-image phenomena, and make the ASEM applicable to various fields. 相似文献