排序方式: 共有40条查询结果,搜索用时 62 毫秒
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中国第1个天线时域近场测量系统 总被引:1,自引:0,他引:1
介绍了天线近场测量的历史以及中国第1个天线时域近场测量系统的建立过程和系统组成.指出时基修正和幅度修正技术是天线近场测量由理论向工程实际转化的关键技术,介绍了修正系统的构成和基本计算方法,并给出了修正前后测量结果的对比.在频域近场技术的背景下对时域近场的技术特点进行了分析,指出了天线时域近场测量技术的独到之处和应用前景. 相似文献
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监测并分析移动通信基站在高层建筑天台架设的定向天线对周围环境的电磁辐射影响水平,探讨高层建筑天台电磁辐射环境的污染防治对策。 相似文献
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目的对某天线进行加速贮存试验研究,利用试验数据进行寿命评估,得到产品的加速因子。方法通过步降应力试验方法对某天线的12台产品进行了四个不同应力量级的高温加速贮存试验,获得产品的退化数据。分别采取两种加速模型对试验数据进行处理,对比确定最优评估方法。结果采用基于漂移布朗运动的加速模型评估得到产品的激活能,从而求出加速因子和贮存寿命。结论步降应力试验方法能加速产品损伤的累积,便于快速获得产品的性能退化数据,而基于漂移布朗运动的评估方法为天线类产品的寿命评估提供了一种新的参考方法。 相似文献
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Caggiano R d'Emilio M Macchiato M Ragosta M 《Environmental monitoring and assessment》2005,108(1-3):67-84
Analyses of sediment and water indicate the presence of heavy metal pollutants like lead, zinc, copper, mercury and cadmium of the river Damodar of India. These metals are responsible for causing morphological deformities of antennae and other parts of chironomid larvae. Percentage of deformity correlated positively with the concentrations of Pb in water and sediment (r > 0.6) at the confluence point. A new severity index, SISS(antenna) has been proposed here to assess deformity at the family or subfamily level. 相似文献
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Summary The major objective of the design of safe crowded transmitting antenna sites is not only to determine a safe zone around each
individual antenna; rather, to establish safety areas at the antenna site itself, as well as, at the neighboring areas. The
requirement is to ascertain the safety regions by considering the following parameters at each Test Point (TP) (or area segment):
the contribution of N co-located radiating antennas to the total radiation incident at the TP, the radiation pattern of each antenna, the near/far
field region of each antenna, and most importantly, the different Permissible Exposure Limits (PELs) associated with each
operating frequency at the antenna site. Implementation of all the above-mentioned aspects in a suitable computer requires
resources that only expert knowledgeable organizations possess. The graphically aided tool presented in this paper facilitates
the calculation of a “safety zone” for RADHAZ around a crowded antenna site from the knowledge of the “safety ranges” which
correspond to the individual transmitting antennas comprising it. 相似文献
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