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非线性传输线产生射频脉冲原理研究 被引量:8
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作者 谢平 徐刚 +2 位作者 廖勇 石小燕 杨周炳 《强激光与粒子束》 EI CAS CSCD 北大核心 2014年第4期5-9,共5页
介绍了非线性传输线的工作原理和色散特性,给出了用于模拟交叉耦合磁饱和非线性传输线的计算方法。算法基于传输线各节点的时域差分方程组进行步进迭代,其中利用J-A模型描述传输线中NiZn铁氧体磁芯的非线性磁化行为,并模拟了非线性传输... 介绍了非线性传输线的工作原理和色散特性,给出了用于模拟交叉耦合磁饱和非线性传输线的计算方法。算法基于传输线各节点的时域差分方程组进行步进迭代,其中利用J-A模型描述传输线中NiZn铁氧体磁芯的非线性磁化行为,并模拟了非线性传输线的工作方式。实验获得了中心频率165MHz的宽带脉冲输出,初步验证了用于产生宽带电磁脉冲的非线性传输线关键技术。 展开更多
关键词 key words nonlinear transmission line simulation method J A model high vohage RADIO frequency PULSE MAGNET lc SATURATION
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Study on Non-Isothermal Decomposition Kinetics of Ephedrini Hydrochloridum 被引量:3
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作者 TangWan-jun ChenDong-hua ShengYu-fang 《Wuhan University Journal of Natural Sciences》 CAS 2003年第02A期443-446,共4页
The thermal decomposition processes of ephedrini hydrochloridum and its kinetics are studied by TG-DTG techniques. A combined method, which includes Achar method, Coats-Redfera method, and Ozawa method, is put forward... The thermal decomposition processes of ephedrini hydrochloridum and its kinetics are studied by TG-DTG techniques. A combined method, which includes Achar method, Coats-Redfera method, and Ozawa method, is put forward for determining kinetic model under non-isothermal conditions. By applying the combined method, it is determined that the thermal decomposition of ephedrini hydrochloridum is subjected to cylindrical symmetric diffusion. And the reaction function is&#402;(&#945;)=2(1-&#945;)?, apparent activation energy (115.26±3.55) kJ·mol&#8722;1, pre-exponential factor 4.62×108 s&#8722;1. Results show that the combined method is feasible and simple. 展开更多
关键词 key words ephedrini hydrochloridum TG DTG technique non isothermal kinetics combined method thermal decomposition
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The Notched Filtering Characteristics of Stratified Volume Holographic Grating
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作者 LI Xiang yang,YAN Yong guo,WANG Guo ping ,YAO Duan zheng Department of Physics,Wuhan University,Wuhan 430072, China 《Wuhan University Journal of Natural Sciences》 CAS 2000年第2期175-177,共3页
Utilizing the tool of beam propagation method (BPM) to calculate the zeroth order diffraction beam intensity, we find SVHG displays notched diffraction response as a function of the readout wavelength. Using the metho... Utilizing the tool of beam propagation method (BPM) to calculate the zeroth order diffraction beam intensity, we find SVHG displays notched diffraction response as a function of the readout wavelength. Using the method of SA and considering the variance of refractive index as the readout wavelength changes, a practiced notch filter can be designed and the period of the filter is discussed. 展开更多
关键词 key words notch filter SVHG beam propagation method (BPM) simulated annealing (SA) method
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Water quality evaluation based on improved fuzzy matter-element method 被引量:21
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作者 Dongjun Liu Zhihong Zou 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2012年第7期1210-1216,共7页
For natural water, method of water quality evaluation based on improved fuzzy matter-element evaluation method is presented. Two important parts are improved, the weights determining and fuzzy membership functions. Th... For natural water, method of water quality evaluation based on improved fuzzy matter-element evaluation method is presented. Two important parts are improved, the weights determining and fuzzy membership functions. The coefficient of variation of each indicator is used to determine the weight instead of traditional calculating superscales method. On the other hand, fuzzy matter-elements are constructed, and normal membership degrees are used instead of traditional trapezoidal ones. The composite fuzzy matter-elements with associated coefficient are constructed through associated transformation. The levels of natural water quality are determined according to the principle of maximum correlation. The improved fuzzy matter-element evaluation method is applied to evaluate water quality of the Luokou mainstream estuary at the first ten weeks in 2011 with the coefficient of variatiola method determining the weights. Water quality of Luokou mainstream estuary is dropping from level I to level II. The results of the improved evaluation method are basically the same as the official water quality. The variation coefficient method can reduce the workload, and overcome the adverse effects from abnormal values, compared with the traditional calculating superscales method. The results of improved fuzzy matter- element evaluation method are more credible than the ones of the traditional evaluation method. The improved evaluation method can use information of monitoring data more scientifically and comprehensively, and broaden a new evaluation method for water quality assessment. 展开更多
关键词 water quality improved fuzzy matter-element evaluation method synthetic evaluation variation coefficient method normal membership key words: water quality improved fuzzy matter-element evaluation method synthetic evaluation variation coefficient method normal membership
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