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基于混合电路模型的亚毫米波谐波混频器的实现 被引量:2
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作者 于伟华 牟进超 +2 位作者 安大伟 吕昕 刘新宇 《北京理工大学学报》 EI CAS CSCD 北大核心 2011年第2期187-190,195,共5页
针对亚毫米波频段混频二极管管对模型获取困难的问题,提出了利用全波电磁场分析算法提取管对无源结构参数,并与管对直流电流-电压特性参数结合获取混合电路等效模型的建模方法.分析了谐波混频器原理,设计并实现了一个工作于2mm波段的二... 针对亚毫米波频段混频二极管管对模型获取困难的问题,提出了利用全波电磁场分析算法提取管对无源结构参数,并与管对直流电流-电压特性参数结合获取混合电路等效模型的建模方法.分析了谐波混频器原理,设计并实现了一个工作于2mm波段的二次谐波混频器.测试结果显示在116~120GHz频率范围内,其变频损耗小于20dB,与仿真数据基本吻合,证明本文提出的混合电路建模方法及所提取模型的有效性. 展开更多
关键词 亚毫米波谐波混频器 混合电路模型 全波电磁场仿真 管对模型
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Numerical method and model for calculating thermal storage time for an annular tube with phase change material 被引量:5
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作者 刘泛函 徐建新 +1 位作者 王辉涛 王华 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第1期217-226,共10页
For calculating the thermal storage time for an annular tube with phase change material (PCM), a novel method is proposed. The method is suitable for either low-temperature PCM or high-temperature PCM whose initial ... For calculating the thermal storage time for an annular tube with phase change material (PCM), a novel method is proposed. The method is suitable for either low-temperature PCM or high-temperature PCM whose initial temperature is near the melting point. The deviation fit is smaller than 8% when the time is below 2x104 s. Comparison between the predictions and the reported experimental data of thermal storage time at same conditions is investigated and good agreements have been got. Based on this method, the performance of the thermal storage unit and the role of natural convection are also investigated. Results show a linear relation between the maximum amount of stored heat and thermal storage time, and their ratio increases with the height of the thermal storage unit. As the thickness of the cavity increases, natural convection plays an increasingly important role in promoting the melting behavior of paraffin. When the thickness of the cavity is small, natural convection restrains the melting behavior of paraffin. 展开更多
关键词 natural convection energy storage modeling heat transfer mass transfer
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Confining Potential Mode in Baryons Spectrum
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作者 ZHAO Hong-Ming SHEN Peng-Nian +2 位作者 DING Yi-Bing LI Xue-Qian ZOU Bing-Song 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第2X期275-286,共12页
Based on the flux tube model, the effects of the confining potentials of different configurations, namely the △-type and the Y-type, on the spectra of baryons are studied on SUSF(6) basis. The baryon spectra are ob... Based on the flux tube model, the effects of the confining potentials of different configurations, namely the △-type and the Y-type, on the spectra of baryons are studied on SUSF(6) basis. The baryon spectra are obtained in a unified manner. Our result shows that by employing either the △-mode or the Y-mode confining potential, one can achieve reasonable baryon spectra. The △-mode may be mostly effective for the short- and medium-distances, while the Y-mode may offer more contributions to the spectra for long-distances. Although the binding energies in baryon spectra may deviate by a few to several tens MeV for different modes, it is hard to determine either one to be dominant by simply evaluating the baryon spectra. One may need to invoke the baryon decay process to make further judgement. 展开更多
关键词 baryons spectra quark model chiral symmetry
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Assessment and Management Strategies for Ungulate Population in Jiangxi Matoushan National Nature Reserve:Predicting the Prey-base from Empirical Field Data 被引量:1
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作者 潘国梁 Alice Laguardia +1 位作者 Falk Huettmann 时坤 《Journal of Resources and Ecology》 CSCD 2016年第5期397-403,共7页
In order to investigate the feasibility of reintroducing the South China tiger (Panthera tigris amoyensis) in the Jiangxi Matoushan National Nature Reserve, field surveys were conducted to assess prey distribution i... In order to investigate the feasibility of reintroducing the South China tiger (Panthera tigris amoyensis) in the Jiangxi Matoushan National Nature Reserve, field surveys were conducted to assess prey distribution in the reserve. Twelve permanent transects were set in three distinct functional zones from February to April 2012 and May to July 2013. A total of 112 ungulate signs were recorded on these transects. In addition, 20 camera traps were used to survey ungulates and predators in 2012, while the following year we extended the survey site by using 30 cameras. Overall, 6641 capture events on 2930 camera days were obtained, presenting a variety of ungulate spe- cies: muntjak (Muntiacus muntjak), tufted deer (Elaphodus cephalophus), serow (Capricornis sumatraensis) and wild boar (Sus scrofa). Population structure and composition of ungulates was compared in different functional zones using a single factor of variance analysis in SPSS software. Significant differences in the distribution of un- gulates were recognized between the core zone and experimental zone, but not in other zones due to differences in habitat types and management practices of the nature reserve. Using ArcGIS analysis and Salford Predictive Modeler software, we ran several predictive models to understand which areas are most suitable for ungulates. We conclude that muntjac and wild boar are mainly distributed in the experimental zone, serow are more common in the core zone, while tufted deer are located evenly in the three functional zones. Finally, suggestions for effective and feasible management strategies and techniques for Matoushan National Nature Reserve were recom- mended based on the results and analysis in this study. 展开更多
关键词 South China tiger Jiangxi Matoushan National Nature Reserve camera traps UNGULATES SPMmodels management strategies
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