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Determination of Structure and Polarity of Si C Single Crystal by X-Ray Diffraction Technique 被引量:1
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作者 郑新和 渠波 +2 位作者 王玉田 杨辉 梁骏吾 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2001年第1期35-39,共5页
Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam pl... Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam ple has a6 H modification.The difference between the integrated intensities m easured byω scan in the triple- axis diffraction set- up finds some convincing evidence that the surface is either a Si- terminated face or C- terminated face.The experi- mental ratios of| F( 0 0 0 L) | 2 / | F( 0 0 0 L) | 2 are in good agreem entwith the calculated ones after the dispersion cor- rections to the atomic scattering factors( L=6 ,12 and18,respectively) .Thus,this m easurem ent technique is con- venient for the application of the materials with remarkable surface polarity. 展开更多
关键词 Si C single crystal polarity hexagonal6 H scattering factor
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直播星背后
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《卫星与网络》 2008年第6期22-25,共4页
应该说中国的直播卫星行业是一个“历经磨难”、“苦命”的行业。很早的时候。行业的有识之士就对直播星行业进行研究,可是,直到等到“头发都白了”,才刚刚看到希望。关于直播星背后的故事也有很多,我们在这里只是选取了几个,让读... 应该说中国的直播卫星行业是一个“历经磨难”、“苦命”的行业。很早的时候。行业的有识之士就对直播星行业进行研究,可是,直到等到“头发都白了”,才刚刚看到希望。关于直播星背后的故事也有很多,我们在这里只是选取了几个,让读者能够了解直播星产业背后的艰辛。 展开更多
关键词 直播卫星行业 电视台 极化 线极化技术 电视节目
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A new scheme of implementing all-optical logic systems exploiting material nonlinearity and polarization based encoding technique 被引量:3
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作者 Debajyoti Samanta Sourangshu Mukhopadhyay 《Optoelectronics Letters》 EI 2008年第3期172-176,共5页
In this letter,the authors propose a new concept of implementing all-optical logic gates by representing the logic states with polarization of an optical signal .As the state of polarization of the light signal is ver... In this letter,the authors propose a new concept of implementing all-optical logic gates by representing the logic states with polarization of an optical signal .As the state of polarization of the light signal is very much suitable for encoding and detecting the bits of data of a digital signal in communication,the scheme may extend some wide applications in all-optical parallel computation and information processing. 展开更多
关键词 光学仪器 逻辑系统 非线性 极化现象 编码技术
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Polarization Projection for 3D Geometry-Based Stochastic Channel Model
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作者 PANG Lihua ZHANG Yang +5 位作者 GONG Fengkui WANG Anyi XIAO Liyuan LIANG Xiao WANG Qiaofeng LI Jiandong 《China Communications》 SCIE CSCD 2015年第10期52-63,共12页
Comprehensive radiation characteristics of polarized antenna are crucial in creating practical channel coefficients for next generation wireless communication system designs.Being currently supported within3 D geometr... Comprehensive radiation characteristics of polarized antenna are crucial in creating practical channel coefficients for next generation wireless communication system designs.Being currently supported within3 D geometry-based stochastic channel models(GSCM),field patterns are technically obtained by chamber measurement(or by its best fitting).However,in some channel related performance analysis scenarios,design insight can be crystallized better by starting the derivations with theoretical co-polarization and cross-polarization components.Specifically,these two components are mathematically linked with field patterns through the proposed polarization projection algorithm.In this manuscript,we focus on revealing the transformation criterion of polarization states between the antenna plane and the propagation plane.In practice,it makes retrieving the field patterns by electromagnetic computation possible.Meanwhile,the impact imposed by distinct antenna orientations is geometrically illustrated and consequently incorporated into the proposed algorithm.This will further facilitate flexible performance evaluation of related radio transmission technologies.Our conclusions are verified by the closed-form expression of the dipole field pattern(via an analytical approach) and by chamber measurement results.Moreover,we find that its 2D degenerative case is aligned with the definitions in 3^(rd) generation partnership project(3GPP)technical report 25.996.The most obvious benefit of the proposed algorithm is to significantly reduce the cost on generating channel coefficients in GSCM simulation. 展开更多
关键词 polarization 3D geometry-based stochastic channel model antenna orientation radiation characteristics dipole chamber measurement channel simulation
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