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小型氢频标磁控管微波腔与空型腔性能的比较 被引量:4
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作者 雒向东 罗崇泰 《甘肃科学学报》 2009年第1期24-27,共4页
用Ansoft HFSS仿真软件建立了小型氢频标空型和磁控管型微波腔模型结构,仿真了2种不同微波腔的谐振频率、品质因数和电磁场结构.通过比较发现空型微波腔当加入壳电极后,腔体内电磁场分布被改变,使得腔体轴线附近磁场分布更加均匀,而电... 用Ansoft HFSS仿真软件建立了小型氢频标空型和磁控管型微波腔模型结构,仿真了2种不同微波腔的谐振频率、品质因数和电磁场结构.通过比较发现空型微波腔当加入壳电极后,腔体内电磁场分布被改变,使得腔体轴线附近磁场分布更加均匀,而电场则主要分布在微波腔壳电极缝隙区域. 展开更多
关键词 氢频标 磁控管腔 空型腔 模式结构 仿真分析 性能比较
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铝铸轧铸嘴空型腔的流场分析
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作者 周英 《材料研究与应用》 CAS 2008年第1期31-33,共3页
利用有限元计算软件建立铝合金连续铸轧的前箱及未放置分流块的铸嘴空型腔的流场模型,对试验数据进行分析,得到有限元计算的空腔流场出口流速的绝对误差及相对误差分布.对空型腔的分析可为铸嘴型腔流场的优化设计提供数据.
关键词 铸轧 空型腔 流场 有限元
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超小型氢频标磁控管微波腔的仿真设计 被引量:3
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作者 雒向东 罗崇泰 《航天制造技术》 2008年第4期24-27,共4页
用Ansoft HFSS仿真软件建立了超小型氢频标磁控管微波腔模型结构,在给定腔体尺寸下,仿真了不同电极间距的空型和磁控管型微波腔谐振频率和品质因数,得出超小型氢频标磁控管微波腔的设计参数,并对实际设计当中影响磁控管型微波腔谐振频... 用Ansoft HFSS仿真软件建立了超小型氢频标磁控管微波腔模型结构,在给定腔体尺寸下,仿真了不同电极间距的空型和磁控管型微波腔谐振频率和品质因数,得出超小型氢频标磁控管微波腔的设计参数,并对实际设计当中影响磁控管型微波腔谐振频率的因素给出了建议。 展开更多
关键词 氢频标 空型腔 磁控管腔 结构参数 仿真设计
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Density Functional Study on Structures and Relative Stability of Gd(H2O)n^3+ (n=8,9)
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作者 肖伟 夏琼琼 +2 位作者 章永凡 宁利新 崔执凤 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2009年第4期395-400,448,共7页
Density functional theory calculations were performed to study the structures and relative stability of the gadolinium complexes, Gd(H2O)n^3+ (n=8,9), in vacuo and in aqueous solution. The polarizable continuum m... Density functional theory calculations were performed to study the structures and relative stability of the gadolinium complexes, Gd(H2O)n^3+ (n=8,9), in vacuo and in aqueous solution. The polarizable continuum model with various radii for the solute cavity was used to study the relative stability in aqueous solution. The calculated molecular geometries for n=8 and 9 obtained in vacuo are consistent with those observed in experiments. It was found that while the nona-aqua complex is favored in the gas phase, in aqueous solution the octa-aqua conformation is preferred. This result, independent of the types of cavities employed, is in agreement with the experimental observation. The reliability of the present calculation was also addressed by comparing the calculated and experimental free energy of hydration, which revealed that the UA0, UAHF, and UAKS cavities are most appropriate when only the first solvation shell is treated explicitly. 展开更多
关键词 Density functional theory Gadolinium hydrate Relative stability Polarizable continuum model Solute cavity
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"Pseudo-invariant Eigen-operator" Method for Deriving Energy-Gap of an Atom-Cavity Jaynes-Cummings Hamiltonian with Atomic Centre-of-Mass Motion
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作者 FAN Hong-Yi TANG Xu-Bing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第6期1003-1006,共4页
Using the "pseudo-invariant eigen-operator" method we find the energy-gap of the Jaynes-Cummings Hamiltonian model of an atom-cavity system. This model takes the atomic centre-of-mass motion into account. The supers... Using the "pseudo-invariant eigen-operator" method we find the energy-gap of the Jaynes-Cummings Hamiltonian model of an atom-cavity system. This model takes the atomic centre-of-mass motion into account. The supersymmetric structure is involved in the Hamiltonian of an atom-cavity system. By selecting suitable supersymmettic generators and using supersymmetrie transformation the Hamiltonian is diagonalized and energy eigenvectors are obtained. 展开更多
关键词 J-C model with atom motion supersymmetric transform pseudo-invariant eigen-operator
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Controlled fabrication and microwave absorbing mechanism of hollow Fe3O4@C microspheres 被引量:3
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作者 Yanhui Hou Huili Yuan +2 位作者 Hang Chen Junhai Shen Liangchao Li 《Science China Chemistry》 SCIE EI CAS CSCD 2017年第6期740-747,共8页
Uniform core-shell SiO2@Fe_3O_4@C microspheres were prepared by a one-step hydrothermal method with SiO_2 microspheres as the template, and the hollow Fe_3O_4@C(HFC) microspheres were achieved via etching SiO_2 templa... Uniform core-shell SiO2@Fe_3O_4@C microspheres were prepared by a one-step hydrothermal method with SiO_2 microspheres as the template, and the hollow Fe_3O_4@C(HFC) microspheres were achieved via etching SiO_2 template. By changing the sizes of SiO_2 microspheres, a series of HFC microspheres with variable cavity sizes were obtained to study the relationship between cavity size and microwave absorbing(MA) performance for the first time. The morphology and structure of samples were characterized in detail. The results showed that the MA performance of HFC sample depended on its cavity size. In particular, the hollow structure was good for improving MA performance and could make MA move to the high-frequency region. More importantly, as the cavity size increases, the resonance frequency of HFC-i(i=1,2, 3, 4) samples moved to a low frequency, and the optimal matching thickness of HFC-i samples was increasing. Among all HFC-i samples, HFC-3 showed the most excellent MA performance,which could be mainly explained by the quarter-wavelength matching model, intrinsical magnetic and dielectric loss. Furthermore,the MA performance of HFC mixture blended by the equal mass fraction of HFC-2, HFC-3 and HFC-4 was the comprehensive results of three HFC-i samples. All the above suggested that the cavity size in HFC sample had a great influence on the MA performance. 展开更多
关键词 microwave absorbing Fe_3O_4@C cavity size
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Supersonic Cavity Flows over Concave and Convex Walls
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作者 A Ran Ye Rajarshi Das +1 位作者 Toshiaki Setoguchi Heuy Dong Kim 《Journal of Thermal Science》 SCIE EI CAS CSCD 2016年第2期145-152,共8页
Supersonic cavity flows are characterized by compression and expansion waves, shear layer, and oscillations inside the cavity. For decades, investigations into cavity flows have been conducted, mostly with flows at ze... Supersonic cavity flows are characterized by compression and expansion waves, shear layer, and oscillations inside the cavity. For decades, investigations into cavity flows have been conducted, mostly with flows at zero pressure gradient entering the cavity in straight walls. Since cavity flows on curved walls exert centrifugal force, the features of these flows are likely to differ from those of straight wall flows. The aim of the present work is to study the flow physics of a cavity that is cut out on a curved wall. Steady and unsteady numerical simulations were carried out for supersonic flow through curved channels over the cavity with L/H = 1. A straight channel flow was also analyzed which serves as the base model. The velocity gradient along the width of the channel was observed to increase with increasing the channel curvature for both concave and convex channels. The pressure on the cavity floor increases with the increase in channel curvature for concave channels and decreases for convex channels. Moreover, unsteady flow characteristics are more dependent on channel curvature under supersonic free stream conditions. 展开更多
关键词 Cavity flow Supersonic Flow Compressible Flow Unsteady flow Pressure Oscillation
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