检索结果-内蒙古大学图书馆

International Workshop on Metamaterials (Meta)

作者： Zhang, S. J. Liu, J. Q. Wang, M. L. Ms, W. M. Liang, W. Liu, X. M. Hou, X. C. National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics

ISBN: (纸本)9781467328081

Frequency selective surfaces (FSS) have attracted researchers from many subjects for decades for its tempting applications such as for radome radar cross section (RCS) reduction, sub-reflector, et. al. Many studies was focused on different type FSS, such as unit shape, dielectric loading, layers of FSS. And it is of popular consideration that double dielectric loading on both sides of FSS be an ideal configuration. In this paper, the type of single side loading, which is more similar to the practical configuration, was studied with the numerical method. And it is found that both the thickness of thick loading layer and the constant of the thin substrate play key roles to the properties of FSS.

关键词： frequency selective surfaces loading LOADING dielectric layer side load numerical methods sidings

来源：评论

学校读者我要写书评

暂无评论

Collimation of Energetic Electrons from a Laser-Target Interaction by a Magnetized Target Back Plasma Preformed by a Long-Pulse Laser

引用

Physical Review Letters 2014年第21期112卷 215003-215003页

作者： H. B. Zhuo Z. L. Chen Z. M. Sheng M. Chen T. Yabuuchi M. Tampo M. Y. Yu X. H. Yang C. T. Zhou K. A. Tanaka J. Zhang R. Kodama College of Science National University of Defense Technology Changsha 410073 People’s Republic of China Graduate School of Engineering Osaka University 2-1 Yamada-oka Suita Osaka 565-0871 Japan MOE Key Laboratory for Laser Plasmas and Department of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240 People’s Republic of China Department of Physics SUPA University of Strathclyde Glasgow G4 0NG United Kingdom Institute of Laser Engineering Osaka University 2-6 Yamada-oka Suita Osaka 565-0871 Japan Institute for Fusion Theory and Simulation and Department of Physics Zhejiang University Hangzhou 310027 People’s Republic of China Institute for Theoretical Physics I Ruhr University Bochum D-44780 Germany Institute of Applied Physics and Computational Mathematics Beijing 100094 People’s Republic of China

It is demonstrated experimentally and by numerical simulations that the presence of a long-pulse-laser-created back plasma on the target backside can focus the relativistic electrons produced by short-pulse laser interaction with the front of a solid target. Comparing this to that without the back plasma, the number density of the fast electrons is increased by one order of magnitude, and their divergence angle is reduced fivefold. The effect is attributed to the absence of the backside sheath electric field and the collimation effect of the megagauss self-generated baroclinic magnetic field there. Such an acceleration scheme can be useful to applications requiring high-energy and charge-density electron bunches, such as fast ignition in inertial fusion.

关键词： COMPUTER simulation LASER pulses ELECTRONS PLASMA acceleration ACCELERATION (Mechanics)

来源：评论

学校读者我要写书评

暂无评论

Attitude maneuver path optimization for small scale spacescraft

Attitude maneuver path optimization for small scale spacescr...

引用

10th IEEE Jubilee International Symposium on Applied Machine Intelligence and Informatics, SAMI 2012

作者： Du, Runle Liu, Jiaqi Wang, Yonghai National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

ISBN: (纸本)9781457701979

During its flight, Spacecrafts need to maneuver its attitude across a number of predefined positions. The order to traverse these attitudes is a combinational optimization problem. In this article, fuel cost is estimated by analyzing the angular momentum change during attitude transitions. Based on this estimation, an optimization algorithm for both fuel-cost and maneuver-time oriented path planner is introduced. Simulation result demonstrated the effectiveness of proposed approach. © 2012 IEEE.

关键词： Attitude control

来源：评论

学校读者我要写书评

暂无评论

Quantum phase transition in a three-level atom-molecule system

引用

Physical Review A 2013年第1期88卷 013602-013602页

作者： Sheng-Chang Li Li-Bin Fu Fu-Li Li School of Science Xi'an Jiaotong University Xi'an 710049 China National Key Laboratory of Science and Technology on Computation Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China Center for Applied Physics and Technology Peking University Beijing 100084 China

We adopt a three-level bosonic model to investigate the quantum phase transition in an ultracold atom-molecule conversion system which includes one atomic mode and two molecular modes. Through thoroughly exploring the properties of energy-level structure, fidelity, and adiabatic geometric phase, we confirm that the system exhibits a second-order phase transition from an atom-molecule mixture phase to a pure molecule phase. We give the explicit expression of the critical point and obtain two scaling laws to characterize this transition. In particular, we find that both the critical exponents and the behavior of the ground-state geometric phase have obviously changed in contrast to a similar two-level model. Our analytical calculations show that the ground-state geometric phase jumps from zero to π/3 at the critical point. This discontinuous behavior has been checked by numerical simulations and it can be used to identify the phase transition in the system.

关键词： QUANTUM phase transitions ATOM-molecule collisions GEOMETRIC quantum phases COMPUTER simulation PHASE transformations (physics) CRITICAL point

来源：评论

学校读者我要写书评

暂无评论

FSS design research for improving the wide-band stealth performance of radar absorbing materials

FSS design research for improving the wide-band stealth perf...

引用

2012 International Workshop on Metamaterials, Meta 2012

作者： Wang, Ming-Liang Zhang, Sheng-Jun Liu, Jia-Qi Liang, Wei Liu, Xue-Mei Liang, X.W. National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematical BeiJing 100076 China

ISBN: (纸本)9781467328081

The frequency selective surface (FSS) is designed to improve the wide-band stealth performance of radar absorbing materials (RAM) at the frequency range from 2GHz to 12GHz. The FSS element structure is designed for thin RAM coating, and the electromagnetic wave reflectivity performance of RAM containing FSS is analyzed by using the numerical simulation. The influence of FSS design parameters on the reflectivity of RAM is researched, and the FSS design parameters include the element geometry parameter, the length of the array periods, and the permittivity of substrate material. The research results show that the three absorbing wide-bands can appear and that the reflectivity is lower than -10dB, so the wide-band stealth performance of RAM containing FSS can be improved at the frequency range from 2GHz to 12GHz. © 2012 IEEE.

关键词： Frequency selective surfaces

来源：评论

学校读者我要写书评

暂无评论

Circulation Variation Over the Western North Pacific and Its Association with Tropical Ssta Over the Indian Ocean and the Pacific

引用

Chinese Journal of Geophysics 2013年第4期56卷 382-399页

作者： YAN Hong‐Ming LI Qin‐Quan YUAN Yuan LI Chong‐Yin Yunnan Climate Center Kunming China National Climate Center Beijing China National Climate Center Beijing China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Institute of Meteorology PLA University of Science and Technology Nanjing China

The circulation variation over the western North Pacific and its relationship between circulation and tropical SSTA were investigated in this paper. The results show that western North Pacific (WNP) anticyclone/cyclone are two significantly anomalous phenomena at mid-low troposphere over WNP, and their variation is related to PJ wave line and zonal wave line at mid-high latitudes of Eurasia. Owing to this interrelation, WNP anticyclone/cyclone can influence the climate over East Asia and Eurasia. The results also show that the relationship between WNP anticyclone/cyclone in summer and SSTA is obviously asymmetric. Generally, evident WNP anticyclone occurs in summer of feeble El Niño years, related with warm SSTA in winter of mature El Niño years over the equatorial east Pacific and warm SSTA in spring and summer of weakening El Niño years over the Indian Ocean, which further displays that the WNP anticyclone plays an important bridge role in El Niño event influence on summer climate over East Asia. But the relationship between the obvious WNP cyclone and SSTA in the Indian Ocean is not steady. The formation and maintain of WNP anticyclone are mainly related to anomalous westerlies resulting from thermal contrast between SSTA over the Indian Ocean and SSTA over the Pacific. The possible cause of asymmetry is further investigated. The results show that the thermal contrasts between Indo-Pacific in El Niño and La Niña summer are accordant, which possibly results in asymmetric relationship between WNP anticyclone/cyclone and SSTA.

关键词： Western North Pacific (WNP) anticyclone/cyclone Indian Ocean basin model (IOBM) El Niño/La Niña event Walker circulation Indo‐Pacific thermal contrast

来源：评论

学校读者我要写书评

暂无评论

Attitude maneuver path optimization for small scale spacescraft

Attitude maneuver path optimization for small scale spacescr...

引用

International Symposium on Applied Machine Intelligence and Informatics (SAMI)

作者： Runle Du Jiaqi Liu Yonghai Wang Test Physics and Numerical Mathematics National Key Laboratory of Science and Technology Beijing China

关键词： Attitude control Fuels Space vehicles Path planning Switches Optimization Heuristic algorithms

来源：评论

学校读者我要写书评

暂无评论

Effective Observing Area based evaluating method for formation design

Effective Observing Area based evaluating method for formati...

引用

IEEE AESS European Conference on Satellite Telecommunications (ESTEL)

作者： Runle Du Jiaqi Liu Yonghai Wang Yizhong Fang Gang Meng National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

When multiple flying vehicles collaborate in locating a target, their formation design is an important factor to the error of location. Based on the analyses of contribution that formation design made to the location error, Effective Observing Area is defined as a criterion to assess formation design. An evaluation method for formation design is then proposed in this paper, which can serve as a guide in further formation design. Digital simulation results have proved the effectiveness and correct of this concept.

关键词： Vectors Target tracking Algorithm design and analysis Space vehicles Extraterrestrial measurements

来源：评论

学校读者我要写书评

暂无评论

A Conservative Lagrangian Scheme for Solving Compressible Fluid Flows with Multiple Internal Energy Equations

引用

Communications in Computational physics 2012年第10期12卷 1307-1328页

作者： Juan Cheng Chi-Wang Shu Qinghong Zeng National Key Laboratory of Science and Technology on Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Division of Applied Mathematics Brown UniversityProvidenceRI 02912USA Institute of Applied Physics and Computational Mathematics Beijing 100088China

Lagrangianmethods arewidely used inmany fields formulti-material compressible flow simulations such as in astrophysics and inertial confinement fusion(ICF),due to their distinguished advantage in capturing material interfaces *** some of these applications,multiple internal energy equations such as those for electron,ion and radiation are *** the past decades,several staggeredgrid based Lagrangian schemes have been developed which are designed to solve the internal energy equation *** schemes can be easily extended to solve problems with multiple internal energy *** such schemes are typically not conservative for the total ***,significant progress has been made in developing cell-centered Lagrangian schemes which have several good properties such as conservation for all the conserved variables and easiness for ***,these schemes are commonly designed to solve the Euler equations in the form of the total energy,therefore they cannot be directly applied to the solution of either the single internal energy equation or the multiple internal energy equations without significant *** modifications,if not designed carefully,may lead to the loss of some of the nice properties of the original schemes such as conservation of the total *** this paper,we establish an equivalency relationship between the cell-centered discretizations of the Euler equations in the forms of the total energy and of the internal *** a carefully designed modification in the implementation,the cell-centered Lagrangian scheme can be used to solve the compressible fluid flow with one or multiple internal energy equations and meanwhile it does not lose its total energy conservation *** advantage of this approach is that it can be easily applied to many existing large application codes which are based on the framework of solving multiple internal energy *** two dimensional numerical examp

关键词： Lagrangian scheme conservative cell-centered internal energy equation compressible fluid flow three-temperaturemodel

来源：评论

学校读者我要写书评

暂无评论

The role of single loading dielectric layer on properties of frequency selective surfaces

The role of single loading dielectric layer on properties of...

引用

International Workshop on Metamaterials

作者： S. J. Zhang J. Q. Liu M. L. Wang W. M. Ms W. Liang X. M. Liu X. C. Hou National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Aerospace Science & Industry Defense Technology R & T Center

Frequency selective surfaces (FSS) have attracted researchers from many subjects for decades for its tempting applications such as for radome radar cross section (RCS) reduction, sub-reflector, ***. Many studies was focused on different type FSS, such as unit shape, dielectric loading, layers of FSS. And it is of popular consideration that double dielectric loading on both sides of FSS be an ideal configuration. In this paper, the type of single side loading, which is more similar to the practical configuration, was studied with the numerical method. And it is found that both the thickness of thick loading layer and the constant of the thin substrate play key roles to the properties of FSS.

关键词： Frequency selective surfaces Dielectrics Substrates Loading Load modeling Frequency modulation Equivalent circuits

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：