检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

北斗三号仅用作追踪的机载设备适航要求分析

北京航空航天大学学报 2024年第4期50卷 1162-1175页

作者：马振洋周中华张帆王鹏柯炳清中国民航大学安全科学与工程学院天津300300 中国民航大学民航航空器适航审定技术重点实验室天津300300 航天恒星科技有限公司北京100094

随着北斗三号卫星导航系统服务正式开通,北斗二号相关适航标准已无法满足当前机载设备应用场景需求,严重制约了北斗在民航领域的应用进程,急需开展北斗三号相应标准的研究与制定。针对北斗在民用航空器中应用第1阶段“仅用作航空器追踪... 详细信息

随着北斗三号卫星导航系统服务正式开通,北斗二号相关适航标准已无法满足当前机载设备应用场景需求,严重制约了北斗在民航领域的应用进程,急需开展北斗三号相应标准的研究与制定。针对北斗在民用航空器中应用第1阶段“仅用作航空器追踪”,对北斗二号与北斗三号开展差异性分析,提出标准修订总体方案,综合考虑适航安全性、机载设备应用场景,结合工业实践,根据设备构型提出指标修订方案,形成审定要素及符合性方法建议,为设备研发与适航取证提供标准支持。仿真分析了设备天线增益、卫星可见性等关键参数,验证了所修订技术指标的正确性。

关键词：技术标准规定北斗三号航空器追踪定位短报文适航

航空发动机电子控制器的高强辐射场干扰及防护

在线全文

学校读者我要写书评

暂无评论

强激光与粒子束 2024年第4期36卷 46-55页

作者：肖国松刘家豪马振洋史春蕾中国民航大学安全科学与工程学院天津300300 中国民航大学民航航空器适航审定技术重点实验室天津300300

针对航空发动机电子控制器(EEC)易受高强辐射场(HIRF)干扰问题,以ZF-M600型EEC为研究对象,通过三维电磁仿真软件CST对EEC建模并进行平面波辐照仿真,模拟HIRF对EEC的干扰效应,仿真结果表明,HIRF可以通过孔缝耦合进入EEC内部并在腔体内部... 详细信息

针对航空发动机电子控制器(EEC)易受高强辐射场(HIRF)干扰问题,以ZF-M600型EEC为研究对象,通过三维电磁仿真软件CST对EEC建模并进行平面波辐照仿真,模拟HIRF对EEC的干扰效应,仿真结果表明,HIRF可以通过孔缝耦合进入EEC内部并在腔体内部产生谐振,谐振频率处电场强度显著增加。依据RTCA DO-160G在400 MHz~4 GHz开展EEC辐射敏感度试验,试验结果表明:EEC失效频点为2.40 GHz和3.48 GHz,敏感模块为模拟量输入输出模块,敏感现象为模拟量数据丢失。EEC失效频点与谐振频率接近,说明EEC失效与腔体谐振有关,在EEC内部贴装吸波材料并进行仿真,分析吸波材料的放置方式和厚度对EEC谐振电磁干扰强度的影响,仿真结果表明,贴装吸波材料可以有效抑制谐振电磁干扰。

关键词：发动机电子控制器高强辐射场辐射敏感度谐振频率电磁防护

独立式北斗机载导航天线适航要求及关键指标分析

在线全文

学校读者我要写书评

暂无评论

现代电子技术 2024年第15期47卷 19-25页

作者：段照斌周行杨乐林马振洋民航航空器适航审定技术重点实验室天津300300 中国民航大学科技创新研究院天津300300 中国民航大学安全科学与工程学院天津300300 中电科航空电子有限公司四川成都610096

北斗卫星导航系统在民航领域的应用已进入“机载导航应用”阶段,与“仅用作定位追踪”阶段相比,此阶段对机载卫星导航系统的要求更为严格。然而,在独立式北斗机载导航天线方面,目前国内仅有“仅用作定位追踪”的标准(CTSO-2C604a)可供参... 详细信息

北斗卫星导航系统在民航领域的应用已进入“机载导航应用”阶段,与“仅用作定位追踪”阶段相比,此阶段对机载卫星导航系统的要求更为严格。然而,在独立式北斗机载导航天线方面,目前国内仅有“仅用作定位追踪”的标准(CTSO-2C604a)可供参考,无法满足“机载导航应用”阶段对天线的适航要求,同时由于目前应用广泛的GPS信号与北斗信号体制不同,其相关标准也无法完全符合独立式北斗机载导航天线要求。为此,文中针对机载导航天线的技术特点,对当前国内外相关标准进行了综合分析,并考虑了适用性、安全性、当前紧迫需求以及未来发展方向,研究了独立式北斗机载导航天线的关键指标,并提出了相应的修订方案。通过研究建立了一套机载导航天线的指标要求和标准体系,旨在为独立式北斗机载导航天线设计提供必要的工业支持。

关键词：独立式导航机载导航天线北斗导航天线增益 B1C信号 G/T值

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

基于射线追踪对矢量分析与复数运算的讨论

电气电子教学学报 2024年第3期46卷 139-142页

作者：徐乐李蕊马振洋史小卫西安电子科技大学电子工程学院西安710071 中国民航大学安全科学与工程学院天津300300

“场论与复变函数”可为学生提供矢量分析和复分析两种数学工具,但教师授课时往往发现学生难以融会贯通。通过引入圆柱形腔体的射线追踪问题,将场论中的矢量分析与复变函数中的复分析结合在一起,提出圆柱形腔体射线追踪的解析公式,使学... 详细信息

“场论与复变函数”可为学生提供矢量分析和复分析两种数学工具,但教师授课时往往发现学生难以融会贯通。通过引入圆柱形腔体的射线追踪问题,将场论中的矢量分析与复变函数中的复分析结合在一起,提出圆柱形腔体射线追踪的解析公式,使学生通过可视化的方式加深理解矢量分析与复分析,提高解决复杂工程问题的能力。

关键词：射线追踪复数乘法矢量分析

Strain effects on valence bands of wurtzite ZnO

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2013年第9期56卷 1684-1688页

作者： QIAO LiPing CHAI ChangChun JIN Zhao YANG YinTang ma zhenyang Key Lab of Wide Band-Gap Semiconductor materials and Devices School of MicroelectronicsXidian University School of Information Engineering Tibet University for Nationalities

Based on the k.p theory of Luttinger-Kohn and Bir-Pikus,analytical E-k solutions for the valence band of strained wurtzite ZnO materials are *** effects on valence band edges and hole effective masses in strained wurtzite ZnO materials are also *** comparison with unstrained ZnO materials,apparent movement of valence band edges such as "light hole band","heavy hole band" and "crystal splitting band" at Γ point is found in strained wurtzite ZnO ***,effective masses of "light hole band","heavy hole band" and "crystal splitting band" for strained wurtzite ZnO materials as the function of stress are *** analytical results can provide a theoretical foundation for the understanding of physics of strained ZnO materials and its applications with the framework for an effective mass theory.

关键词： strained ZnO band structure effective mass

Analysis of temperature-dependent characteristics of a 4H-SiC metal-semiconductor-metal ultraviolet photodetector

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2012年第34期57卷 4427-4433页

作者： CHEN Bin YANG YinTang XIE XuanRong WANG Ning ma zhenyang SONG Kun ZHANG XianJun Key Laboratory of Ministy of Education for Wide Band-Gap Semiconductor materials and Devices School of MicroelectronicsXidian UniversityXi'an 710071China Xi'an Electronic Engineering Research Institute Xi'an 710100China No.771 Institute of Microelectronics Technology Xi'an 710054China

We investigate the temperature dependence of current-voltage and spectral response characteristics of a 4H-SiC metal-semicon-ductor-metal (MSM) ultraviolet photodetector in the temperature range from room temperature to 800 K with two-dimensional (2D) numerical simulator ISE-DESSIS. It is found that the dark current and photocurrent increase with the increasing temperature. For the range of 500-800 K, the dark current increases by nearly a factor 3.5 every 150 K larger than that of photocurrent, leading to a negative effect on photodetector current ratio (PDCR). Nevertheless, the PDCR is still greater than 200 even at 800 K, which exhibits the excellent thermal stability. In addition, the responsivity has an unsymmetrical trend. As temperature rises, it is clear that a remarkable red-shift of 12 nm occurs and overall responsivity is enhanced for longer wavelength. While the short-wave-length response remains relatively independent of temperature. The mechanism of indirect and direct band absorption transition is responsible for temperature-dependent spectrum distribution. These findings provide a significant insight on the design of the MSM detector operated at elevated temperature.

关键词：温度依赖性 4H-SiC 光谱响应特性光检测器半导体金属紫外线数值模拟器

Effect of electrolyte cation-mediated mechanism on electrocatalytic carbon dioxide reduction

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第7期35卷 139-146页

作者： Yuan Dong Mutian ma zhenyang Jiao Sheng Han Likun Xiong Zhao Deng Yang Peng Soochow Institute of Energy and material Innovations College of EnergyJiangsu Key Laboratory of Advanced Carbon Materials and Wearable Energy TechnologiesSoochow UniversitySoochow 215006China Jiangsu Key Laboratory of Advanced Negative Carbon Technologies Soochow UniversitySoochow 215123China School of Chemistry and Chemical Engineering Shihezi UniversityShihezi 832003China School of Chemical and Environmental Engineering Shanghai Institute of TechnologyShanghai 201418China

The steep reduction in costs and systematic optimization of renewable electricity has ignited an intensifying interest in harnessing electroreduction of carbon dioxide(CO_(2)RR)for the generation of chemicals and *** focus of research over the past few decades has been on the optimization of the electrode and the electrolyte ***,cation species in the latter have recently been found to dramatically alter the selectivity of CO_(2)RR and even their catalytic activity by multiple orders of *** a result,the selection of cations is a critical factor in designing catalytic interfaces with high selectivity and efficiency for targeted *** decision-making regarding cation selection relies on a comprehensive understanding of prevailing electrolyte effect models that have been used to elucidate observed experimental *** this perspective,we review the hypotheses that explain how electrolyte cations influence CO_(2)RR by mechanisms such as through tuning of the interfacial electric field,buffering of the local pH,stabilization of the key intermediates and regulation of the interfacial *** endeavor is to elucidate the molecular mechanisms underpinning cation effects,thus fostering the evolution of more holistic and universally applicable predictive *** this regard,we highlight the current challenges in this area of research,while also identifying potential avenues for future investigations.

关键词： CO_(2)electrocatalytic reduction Cation effects Catalytic mechanisms Catalytic interfaces Electric double layer

Physical properties of B_4N_4-Ⅰ and B_4N_4-Ⅱ:First-principles study

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第3期28卷 283-290页

作者： zhenyang ma Peng Wang Fang Yan Chunlei Shi Yi Tian Key Laboratory of Civil Aircraft Airworthiness Technology Civil Aircraft Airworthiness and Repair Key Laboratory of TianjinSchool of AirworthinessCivil Aviation University of China

The structural, mechanical, electronic, mechanical anisotropy, and thermal properties of boron nitride(BN) polymorphs, such as B_4 N-4-Ⅰ and B4 N4-Ⅱ, are investigated under ambient pressure utilizing first-principles generalized gradient approximation calculations using an ultrasoft pseudopotential scheme. The phonon spectra and elastic constants reveal that B_4 N_4-Ⅰ is dynamically and mechanically stable at the pressure of 0 GPa and temperature of 0 K. Anisotropic calculations indicate that both B_4 N_4-Ⅰ and B4 N4-Ⅱ exhibit higher anisotropy of Young's modulus than cubic BN(c-BN). B_4 N_4-Ⅱ and B_4 N_4-Ⅰ present indirect and wide band gaps of 5.32 eV and 4.86 eV, respectively. In addition, B_4 N_4-Ⅰ is more brittle than B_4 N_4-Ⅱ. Moreover, the minimum thermal conductivity,κmin, of B4 N4-Ⅱ at 300 K is 1.92 W/(cm·K), which is slightly higher than those of B_4 N_4-Ⅰ and c-BN(1.84 W/(cm-K) and 1.83 W/(cm-K), respectively. However, κ_(min) of B_4 N_4-Ⅰ is slightly higher than that of c-BN.

关键词： BN polymorphs mechanical properties electronic properties mechanical anisotropic properties

在线全文

学校读者我要写书评

暂无评论

电磁脉冲作用下二极管二次击穿电热特性

西安电子科技大学学报 2013年第2期40卷 36-42页

作者：任兴荣柴常春马振洋杨银堂西安电子科技大学宽禁带半导体材料与器件教育部重点实验室陕西西安710071

对p-n-n+二极管在电磁脉冲作用下的二次击穿过程进行了二维瞬态电热仿真,研究了二次击穿过程中二极管内部的电场和电流密度分布以及端电压和端电流随电磁脉冲作用时间的变化,探索了二次击穿触发温度、触发电流和触发能量随延迟时间的变... 详细信息

对p-n-n+二极管在电磁脉冲作用下的二次击穿过程进行了二维瞬态电热仿真,研究了二次击穿过程中二极管内部的电场和电流密度分布以及端电压和端电流随电磁脉冲作用时间的变化,探索了二次击穿触发温度、触发电流和触发能量随延迟时间的变化规律.研究结果表明,电磁脉冲作用下二极管的二次击穿属于热二次击穿,电流集中并非二次击穿发生的必要条件,触发温度和触发电流随延迟时间的减小而增大,但触发能量则随延迟时间的减小而减小,仿真得到的电磁脉冲损伤能量阈值与实验数据吻合较好.

关键词：电磁脉冲二极管二次击穿触发温度损伤阈值