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GIS技术在无线电波场强分析中的应用研究 被引量:8
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作者 孙红云 王亮 +1 位作者 王涛 范荣双 《测绘科学》 CSCD 北大核心 2007年第6期104-106,共3页
无线电波场强分析在广播电视台站规划中是一项重要的工作,采用传统的电波传播模型进行场强预测时,相关的计算大多依据纸质地图用手工进行,工作强度高,结果精确性低。本文结合地理信息系统(GIS)的空间数据管理、数字地形分析等技术,构建... 无线电波场强分析在广播电视台站规划中是一项重要的工作,采用传统的电波传播模型进行场强预测时,相关的计算大多依据纸质地图用手工进行,工作强度高,结果精确性低。本文结合地理信息系统(GIS)的空间数据管理、数字地形分析等技术,构建台站与发射机实体对象,基于地理空间信息环境实现了典型电波传播场强分析模型,提高了场强计算的效率和空间位置精度,同时将人口分布信息应用到模型中,增强了台站规划的科学性;最后讨论了GIS技术在电波传播模型中进一步应用的前景。 展开更多
关键词 场强分析 电波传播模型 GIS 地形分析
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Protek公司RF信号场强分析仪
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《电子产品世界》 2004年第09B期50-51,共2页
关键词 Protek公司 RF信号 场强分析 3290 技术规格 信道
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深层次GSM无线网络优化策略─—场强测试分析法 被引量:2
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作者 蔡伟明 《移动通信》 2001年第2期14-19,共6页
本文首先简述了GSM无线网络优化的常规方法,然后从提高、完善网络服务质量出发,对利用场强测试分析法引进深层次的GSM无线网络优化作了细致、具体的探讨。
关键词 GSM 移动通信 无线网络优化 场强测试分析
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一例500kV变压器感应耐压试验击穿原因分析及处理 被引量:1
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作者 李威 张进 +3 位作者 符劲松 陈斌 刘要峰 尹旭 《湖南电力》 2020年第1期36-40,共5页
本文针对一例出厂验收过程中的耐压击穿事故,通过油色谱分析、吊芯检查找到了放电击穿点,通过对比设计图确定了中性点和低压引线间缺少绝缘垫块的施工缺陷,分别采用模拟电荷法和有限元法搭建模型,计算了引线间的场强分布。计算结果表明... 本文针对一例出厂验收过程中的耐压击穿事故,通过油色谱分析、吊芯检查找到了放电击穿点,通过对比设计图确定了中性点和低压引线间缺少绝缘垫块的施工缺陷,分别采用模拟电荷法和有限元法搭建模型,计算了引线间的场强分布。计算结果表明在幅值电压下,无垫块时极间场强达到200 kV/cm,发生油中放电击穿概率大,按标准安装后最大场强不超过40 kV/cm,绝缘裕度较大。文中最后对此提出了预防措施,有利于设备质量管控和绝缘考核分析工作的开展。 展开更多
关键词 大容量变压器 感应耐压试验 有限元法 场强分析 质量管控
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关于感生电场强分布的一个计算方法
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作者 白建忠 《马钢职工大学学报》 1995年第1期19-22,共4页
关键词 感生电场 计算方法 场强分析
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船舶自动识别系统性能半实物仿真方法研究 被引量:5
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作者 马枫 严新平 初秀民 《系统仿真学报》 CAS CSCD 北大核心 2013年第6期1315-1320,共6页
船舶自动识别系统(Automatic Identify System,AIS)是当今海事管理主要无线监管工具。为全面分析其在复杂地形下的误包特征,设计了一种半实物仿真研究方法,模拟任意场强与干扰特征的AIS信号,采用真实的接收机评估误包率,并使用Okumura-H... 船舶自动识别系统(Automatic Identify System,AIS)是当今海事管理主要无线监管工具。为全面分析其在复杂地形下的误包特征,设计了一种半实物仿真研究方法,模拟任意场强与干扰特征的AIS信号,采用真实的接收机评估误包率,并使用Okumura-Hata模型建立了场强与距离的对应模型,用于仿真AIS网络实际运行中可能遇到的地形衰减,以及各种常见干扰。使用该方法可以有效寻找出信号衰减的误码特征,验证不同干扰信号的特性。通过深圳AIS信号干扰实例,证明了半实物仿真方法与平台的实用性。该研究方法可以为最终实现AIS设备的硬件设计优化提供平台,并为基站的最佳布置方案提供实验基础。 展开更多
关键词 船舶自动识别系统 半实物仿真 性能研究 场强分析 误码率
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短波发射机场强仿真分析程序设计与研究
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作者 仰蕾 谢勇 +2 位作者 魏世东 张伟松 杨颖 《广播电视信息》 2023年第7期91-93,共3页
本文简单叙述了短波通信的原理,详细阐述了基于ITS模型的短波发射机场强仿真分析程序的主要功能和场强预测工作流程的操作步骤,并结合具体的实例,介绍了场强分析界面和参数设置界面的实际应用。
关键词 短波通信 传播链路 仿真模型 发射机场强仿真分析程序 软件界面
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多频无线电波透视探测技术在煤层冲刷带探测中的应用 被引量:12
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作者 段天柱 《煤矿安全》 CAS 北大核心 2019年第5期146-149,共4页
煤层冲刷带通常会引起煤层形态和厚度的变化,给煤矿开采带来不利影响。利用煤层冲刷带与煤层之间存在电性差异,采用多频无线电波透视探测技术可以有效圈定煤层冲刷带。结合不同频率及探测点距条件下电磁波透视探测成果,分析了不同条件... 煤层冲刷带通常会引起煤层形态和厚度的变化,给煤矿开采带来不利影响。利用煤层冲刷带与煤层之间存在电性差异,采用多频无线电波透视探测技术可以有效圈定煤层冲刷带。结合不同频率及探测点距条件下电磁波透视探测成果,分析了不同条件下电磁波透视探测的适用性。实际探测成果表明,电磁波透视探测技术是一种有效的回采工作面地质异常体探测手段,在保证透射电磁波信号强度的前提下,探测频率与较小的探测点距能有效提高分辨率。 展开更多
关键词 多频探测 无线电波透视 煤层冲刷带 衰减系数成像 场强分析
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Analysis of secondary flow in shell-side channel of trisection helix heat exchangers 被引量:3
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作者 王伟晗 陈亚平 +1 位作者 操瑞兵 施明恒 《Journal of Southeast University(English Edition)》 EI CAS 2010年第3期426-430,共5页
The flow characteristics of shell-side fluid in the tube-and-shell heat exchangers with trisection helical baffles with 35° inclined angles are numerically analyzed. The secondary flow distribution of the fluid i... The flow characteristics of shell-side fluid in the tube-and-shell heat exchangers with trisection helical baffles with 35° inclined angles are numerically analyzed. The secondary flow distribution of the fluid in the shell-side channel is focused on. The results on meridian planes indicate that in the shell-side channel, the center part of fluid has an outward tendency because of the centrifugal force, and the peripheral region fluid has an inward tendency under the centripetal force. So in a spiral cycle, the fluid is divided into the upper and lower beams of streamlines, at the same time the Dean vortices are formed near the left baffle, and then the fluid turns to centripetal flow near the right baffle. Finally the two beams of streamlines merge in the main flow. The results of a number of parallel slices between two parallel baffles with the same sector in a swirl cycle also show the existence of the secondary flow and some backward flows at the V-gaps of the adjacent baffles. The secondary flows have a positive effect on mixing fluid by promoting the momentum and mass exchange between fluid particles near the tube wall and in the main stream, and thus they will enhance the heat transfer of the helix heat exchanger. 展开更多
关键词 trisection helix heat exchangers secondary flow Dean vortices heat transfer enhancement flow field analysis
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DIMENSIONLESS ANALYSIS AND LOCATION OF ELECTRIC FIELD INDUCED BY MAGNETIC COIL
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作者 乔清理 王明时 田心 《Transactions of Tianjin University》 EI CAS 2000年第1期73-76,共4页
A model of magnetic stimulation is presented for analysis of the spatial distributions of the electric field induced by magnetic coils.Dimensionless analysis is introduced and makes the factors influencing the magnitu... A model of magnetic stimulation is presented for analysis of the spatial distributions of the electric field induced by magnetic coils.Dimensionless analysis is introduced and makes the factors influencing the magnitude of electric field into two parts:c (represents the stimulation conditions),and E 0 (reflects the geometry of coil).By 3 D simulation of the induced electric field of two kinds of coils,the effect of magnetic stimulation can be demonstrated and the factors influencing stimulating focality and depth are identified.The principles for determining the electric field magnitude,focality and magnetic stimulation depth when designing a reasonable coil and stimulator and achieving ideal stimulating effect are discussed. 展开更多
关键词 magnetic stimulator induced electric field distribution focality magnetic stimulation depth
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Mechanism analysis and process optimization of sand and plug removal with rotating jet in horizontal well 被引量:2
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作者 祝效华 李佳南 童华 《Journal of Central South University》 SCIE EI CAS 2013年第6期1631-1637,共7页
In the view of the problems existing in horizontal well,such as sand depositing and cleaning difficulty of borehole,a technology with rotating jet suitable to resolution of the problems was presented.Based on liquid s... In the view of the problems existing in horizontal well,such as sand depositing and cleaning difficulty of borehole,a technology with rotating jet suitable to resolution of the problems was presented.Based on liquid solid two-phase flow theory,the analyses on the sand movement law and the swirling field influential factors were conducted.Results show that:1) With the increasing of displacement in horizontal section annulus,swirling field strength increases,and when the displacement is constant,the closer from the nozzle,the stronger the swirling field strength is;2) Head rotating speed and liquid viscosity have little influence on the swirling field strength,but the sand-carrying rate of fluid can increase by increasing liquid viscosity in a certain range;3) Rotating the string and reducing its eccentricity in annulus are conducive for sand migration in the annulus;4) The sand can be suspended and accelerated again and the swirling field strength is enhanced by the helix agitator.Hence,the research results provide the theoretical basis for the design and application of rotating jet tool. 展开更多
关键词 horizontal well sand and plug removal rotating jets sand depositing influence factors
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Analyzing the Impacts of Minimum Wage Standards on Reducing the Working Poor in China
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作者 Yongjian Hu 《Sociology Study》 2014年第7期573-580,共8页
During the past decades, the transformation of the labor market has significantly impacted on workers' wage structures and their employment in China. Along with the widening wage gaps and the growing income inequalit... During the past decades, the transformation of the labor market has significantly impacted on workers' wage structures and their employment in China. Along with the widening wage gaps and the growing income inequalities, the size of non-standard jobs expanded rapidly in China's urban labor market. As a result of this, the concept of working poor has become increasingly applicable to social and labor market realities in China, Based on the household survey data and by using quantitative analysis, this paper attempts to examine the interaction between the compulsory minimum wage standards and the working poor in the period of China's economic transition. The results show that for those whose monthly wages higher than the compulsory minimum wage standards were less likely to work poor and that workers with wages lower than the minimum wage floor were vulnerable to working poor, which supported the expectation that the implementation of compulsory minimum wages would help to reduce the risk of being a member among the working poor in China's urban labor market. 展开更多
关键词 Working poor minimum wage standards wage gaps logit model
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