检索结果-内蒙古大学图书馆

The sublimation energy of metal versus temperature and pressure and its influence on blow-off impulse

World Academy of science, Engineering and technology 2011年 81卷 620-623页

作者： Tang, Wenhui Wang, Daorong Huang, Xia Ran, Xianwen Institute of Technological Physics College of Science National University of Defense Technology Changsha 410073 China National Key Laboratory of Science and Technology Test Physics and Numerical Mathematics Beijing 100076 China

Based on the thermodynamic theory, the dependence of sublimation energy of metal on temperature and pressure is discussed, and the results indicate that the sublimation energy decreases linearly with the increase of temperature and pressure. Combined with this result, the blow-off impulse of aluminum induced by pulsed X-ray is simulated by smoothed particle hydrodynamics (SPH) method. The numerical results show that, while the change of sublimation energy with temperature and pressure is considered, the blow-off impulse of aluminum is larger than the case that the sublimation energy is assumed to be a constant.

关键词： Aluminum

来源：评论

学校读者我要写书评

暂无评论

Contrasts of bimodal tropical instability waves(TIWs)-induced wind stress perturbations in the Pacific Ocean among observations,ocean models,and coupled climate models

引用

Journal of Oceanology and Limnology 2024年第1期42卷 1-23页

作者： Kai MA Chuanyu LIU Junli XU Fan WANG School of Mathematics and Physics Research Institute for Mathematics and Interdisciplinary SciencesQingdao University of Science and TechnologyQingdao 266100China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao 266237China

The coupling between wind stress perturbations and sea surface temperature(SST)perturbations induced by tropical instability waves(TIWs)in the Pacific Ocean has been revealed previously and proven crucial to both the atmosphere and ***,an overlooked fact by previous studies is that the loosely defined“TIWs”actually consist of two modes,including the Yanai wave-based TIW on the equator(hereafter eTIW)and the Rossby wave-based TIW off the equator(hereafter vTIW).Hence,the individual feedbacks of the wind stress to the bimodal TIWs remain *** this study,individual coupling relationships are established for both eTIW and v TIW,including the relationship between the TIW-induced SST perturbations and two components of wind stress perturbations,and the relationship between the TIW-induced wind stress perturbation divergence(curl)and the downwind(crosswind)TIW-induced SST *** show that,due to different distributions of eTIW and vTIW,the coupling strength induced by the eTIW is stronger on the equator,and that by the vTIW is stronger off the *** results of any of eTIW and vTIW are higher than those of the loosely defined *** further investigated how well the coupling relationships remained in several widely recognized oceanic general circulation models and fully coupled climate ***,the coupling relationships cannot be well represented in most numerical ***,we confirmed that higher resolution usually corresponds to more accurate ***,the coupling models established in this study are complementary to previous research and can be used to refine the oceanic and coupled climate models.

关键词： bimodal tropical instability waves mesoscale air-sea interaction coupled models Yanai wave

来源：评论

学校读者我要写书评

暂无评论

Progress and prospective of electromagnetic periodic structures 4

Progress and prospective of electromagnetic periodic structu...

引用

4th International Applied Computational Electromagnetics Society Symposium in China, ACES-China 2021

作者： Zhang, Shengjun Mu, Lei Shao, Chunshou Ai, Xia Wang, Weidong Chai, Song Cui, Yichun Liu, Shengdong Sun, Cuiyun Zhou, Nan Xie, Lei Li, Chunyu Jiao, Luting Wang, Yue Qi, Zhaohui Wang, Minghao Yong, Zhengyu Sun, Yuan Kong, Dewang National Key Laboratory of Science Technology on Test Physics and Numerical Mathematics Beijing China The Star of Aerospace Innovation Research Institute in Changsha Hunan Changsha China Beijing Institute of Space Long March Vehicles Beijing China Institute of Survival Technology Effectiveness Evaluation of Flying Vehicle Beijing China National Key Laboratory of Science Technology on Electromagnetic Scattering Beijing China

ISBN: (纸本)9781733509619

Periodic structures have attracted interests of researches for decades, and they were discovered more and more useful properties, and have been applied to many fields. Furthermore, more and more novel concept and phenomena based on periodic structures were proposed and found, such as tunable electromagnetic properties of some structures. In this paper, recent progress on two of the periodic structures, i.e., FSS and metamaterials and their variations, were revie, and the physical nature of these structures analog to materials were also suggested. © 2021 Applied Computational Electromagnetics Society (ACES).

关键词： Periodic structures

来源：评论

学校读者我要写书评

暂无评论

RCS analysis of disk target covered with non-uniform plasma

RCS analysis of disk target covered with non-uniform plasma

引用

IET International Radar Conference 2015

作者： Runhui Wu Jiaqi Liu Xin Liu Gang Meng Aimin Ren Zhaohui Qi National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical Beijing 100076

ISBN: (纸本)9781510822023

This paper presents a model of RCS characteristic of non-uniform plasma sheltering disk target, by considering the absorption and refraction of electromagnetic wave, and combining graphic electromagnetic and ray tracking methods. The results show that: (1) RCS is reduced more than 10dB at wide-band frequency of electromagnetic wave, when the incident direction of electromagnetic wave is near the vertical surface. (2)For optimization of RCS reduction scheme, it is effective to optimize the relation between the plasma parameters (including electronic density, collision frequency, over-dense target scale) and incident wavelength. When the area of over-dense surface was larger than the target scale, the larger the collision frequency could lead to greater RCS reduction. When the area of over-dense scale was smaller than target, the RCS reduction has to be achieved by increasing electronic density and collision frequency.

关键词： Disk Target Electromagnetic Wave Non-uniform Plasma Radar Cross Section(RCS)

来源：评论

学校读者我要写书评

暂无评论

The seasonal variations in the significant wave height and sea surface wind speed of the China's seas

引用

Acta Oceanologica Sinica 2015年第9期34卷 58-64页

作者： ZHENG Chongwei PAN Jing TAN Yanke GAO Zhansheng RUI Zhenfeng CHEN Chaohui College of Meteorology and Oceanography People’s Liberation Army University of Science and Technology National Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of Sciences Dalian Naval Academy

Long-term variations in a sea surface wind speed （WS） and a significant wave height （SWH） are associated with the global climate change, the prevention and mitigation of natural disasters, and an ocean resource exploitation, and other activities. The seasonal characteristics of the long-term trends in China＇s seas WS and SWH are determined based on 24 a （1988-2011） cross-calibrated, multi-platform （CCMP） wind data and 24 a hindcast wave data obtained with the WAVEWATCH-III （WW3） wave model forced by CCMP wind data. The results show the following. （1） For the past 24 a, the China＇s WS and SWH exhibit a significant increasing trend as a whole, of 3.38 cm/（s.a） in the WS, 1.3 cm/a in the SWH. （2） As a whole, the increasing trend of the China＇s seas WS and SWH is strongest in March-April-May （MAM） and December-January-February （DJF）, followed by June-July-August （JJA）, and smallest in September-October-November （SON）. （3） The areal extent of significant increases in the WS was largest in MAM, while the area decreased in JJA and DJF; the smallest area was apparent in SON. In contrast to the WS, almost all of China＇s seas exhibited a significant increase in SWH in MAM and DJF; the range was slightly smaller in JJA and SON. The WS and SWH in the Bohai Sea, the Yellow Sea, East China Sea, the Tsushima Strait, the Taiwan Strait, the northern South China Sea, the Beibu Gull and the Gulf of Thailand exhibited a significant increase in all seasons. （4） The variations in China＇s seas SWH and WS depended on the season. The areas with a strong increase usually appeared in DJF.

关键词： sea surface wind speed significant wave height long-term variation seasonal difference

来源：评论

学校读者我要写书评

暂无评论

Intercept Strategy for Maneuvering Target Based on Deep Reinforcement Learning

Intercept Strategy for Maneuvering Target Based on Deep Rein...

引用

第40届中国控制会议

作者： Xu Wang Yuanli Cai Yizhong Fang Yifan Deng School of Automation Science and Engineering Xi'an Jiaotong University National Key Laboratory of Science Technology on Test Physics & Numerical Mathematics

A novel interception strategy for high-speed maneuvering target based on reinforcement learning（RL） algorithm is proposed. With reshaped reward function and observation consisting solely of relative position information and path angle, the interception policy is trained by Deep Deterministic Policy Gradient（DDPG） algorithm. The results of training and test indicate that the proposed guidance law can approximate the optimal control model of the maneuvering target interception and show the superiority over traditional method.

关键词： Exoatmospheric Interception Maneuvering Target Deep Reinforcement Learning DDPG

来源：评论

学校读者我要写书评

暂无评论

L2 Gain-Based Guidance Law with Acceleration Saturation

L2 Gain-Based Guidance Law with Acceleration Saturation

引用

The Society of Instrument and Control Engineers Annual Conference 2015

作者： Kezi Meng Di Zhou Runle Du Department of Control Science and Engineering Harbin Institute of Technology National Key Laboratory of Science and Technology on Test Physics&Numerical Mathematics

This paper focuses on the problem of designing a 2L, gain-scheduling state-feedback guidance law with acceleration saturation based on linear matrix inequality(LMI) approach. The planar target-missile engagement is described in a polar coordinate system and the target acceleration is viewed as unpredictable disturbance. Saturated state-feedback is placed into the convex hull of a group of linear feedbacks. Furthermore,2L gain guidance problem is formulated and solved as an optimization problem with parameter-dependent LMI constraints which are then converted into a finite number of LMIs to facilitate the computation. Finally, simulation results demonstrate that the proposed guidance law copes with acceleration saturation effectively and obtains excellent guidance performance in terms of miss distance.

关键词： L2 gain guidance law acceleration saturation LPV system linear matrix inequality(LMI)

来源：评论

学校读者我要写书评

暂无评论

Dominant SST Mode in the Southern Hemisphere Extratropics and Its Influence on Atmospheric Circulation

引用

Advances in Atmospheric sciences 2018年第7期35卷 881-895页

作者： Fei ZHENG Jianping LI Fred KUCHARSKI Ruiqiang DING Ting LIU State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences State Key Laboratory of Earth Surface Processes and Resource Ecology and College of Global Change and Earth System Science Beijing Normal University Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology Earth System Physics Section Abdus Salam International Centre for Theoretical Physics Center of Excellence for Climate Change Research Department of MeteorologyKing Abdulaziz University Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technology State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography

The variability in the Southern Ocean（SO） sea surface temperature（SST） has drawn increased attention due to its unique physical features; therefore, the temporal characteristics of the SO SST anomalies（SSTA） and their influence on extratropical atmospheric circulation are addressed in this study. Results from empirical orthogonal function analysis show that the principal mode of the SO SSTA exhibits a dipole-like structure, suggesting a negative correlation between the SSTA in the middle and high latitudes, which is referred to as the SO Dipole（SOD） in this study. The SOD features strong zonal symmetry, and could reflect more than 50% of total zonal-mean SSTA variability. We find that stronger（weaker） Subantarctic and Antarctic polar fronts are related to the positive（negative） phases of the SOD index, as well as the primary variability of the large-scale SO SSTA meridional gradient. During December–January–February, the Ferrel cell and the polar jet shift toward the Antarctic due to changes in the SSTA that could be associated with a positive phase of the SOD, and are also accompanied by a poleward shift of the subtropical jet. During June–July–August, in association with a positive SOD, the Ferrel cell and the polar jet are strengthened, accompanied by a strengthened subtropical jet. These seasonal differences are linked to the differences in the configuration of the polar jet and the subtropical jet in the Southern Hemisphere.

关键词： extratropical sea surface temperature air–sea interaction Southern Annular Mode

来源：评论

学校读者我要写书评

暂无评论

Insect wing-beat frequency automatic extraction and experimental verification with a Ku-band insect radar system

Insect wing-beat frequency automatic extraction and experime...

引用

IET International Radar Conference 2018, IRC 2018

作者： Zhang, Tianran Liu, XiangRong Hu, Cheng Wang, Rui Liu, Changjiang Li, Wenqing Radar Research Laboratory School of Information and Electronics Beijing Institute of Technology Beijing100081 China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China Key Laboratory of Electronic and Information Technology in Satellite Navigation Beijing Institute of Technology Ministry of Education Beijing100081 China

The wing-beat frequency is one of the most important behavioural parameters of migratory insects and is widely used to distinguish insect species due to the diversity of wing-beat frequency among different species. Traditional insect radar has been able to achieve automatic extraction of the wing-beat frequency. However, its low-range resolution and fixed threshold detection may cause false alarms and reduce the precision of wing-beat frequency. The authors' Ku-band insect radar system enables high-resolution, full-polarised detection of insects, but has not achieved automatic extraction of wing-beat frequency yet. The authors propose an insect wing-beat frequency automatic extraction algorithm based on a Ku-band insect radar system. The algorithm adopts the constant false alarm rate detector and tracks the association algorithm to get target echo automatically and combines the amplitude spectrum method and the phase spectrum method to achieve wing-beat frequency extraction. The authors carried out the outfield experiment using the radar system and used the collected data to test the proposed algorithm. The experiment results confirm that the algorithm can extract the wing-beat frequency of insects automatically based on the Ku-band insect radar system, which can improve system efficiency. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Errors

来源：评论

学校读者我要写书评

暂无评论

Shock Response in Cage-like Polynitrocubane High-Energy-Density Materials: Competition between Strain Energy and Structural Symmetry

引用

Energetic Materials Frontiers 2025年

作者： Qing-guan Song Li Meng Sheng-li Jiang Lei Zhang Ze-yao Mo Institute of Applied Physics and Computational Mathematics Beijing 100088 China CAEP Software Center for High Performance Numerical Simulation Beijing 100088 China Institute of Chemical Materials China Academy of Engineering Physics Mianyang 621999 China School of Materials Science & Engineering Beijing Institute of Technology Beijing 100081 China State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of Technology Beijing 100081 China

The cage-like structures provide a unique combination of strain energy for enhanced energy storage and hyperstatic constraints to stabilize the system, positioning them as promising pioneers in advancing high-energy-density materials (HEDMs). However, the shock response of cage-like HEDMs is highly complex and exhibits significant variability, posing a grand challenge in the underlying mechanisms. This study reveals that the shock response of cage-like HEDMs is regulated by the interplay between strain energy and structural symmetry, and introduces a physical model to quantitatively describe how they determine shock stability. The investigated systems include a comprehensive series of cage-like polynitrocubane HEDMs, with each carbon atom in the backbone progressively functionalized with nitro groups. Ab initio molecular dynamics (AIMD) simulations were employed to simulate dynamic and kinetic responses at shock velocities ranging from 8 km·s -1 to 11 km·s -1 , with validation provided by consistent Hugoniot curves that align with reported experimental data. Nitro groups at the carbon-based cage structure, recognized as explosion functional groups, were found to substantially increase the system's strain energy. However, an increasing number of nitro groups also intensified electrostatic repulsion among oxygen lone pairs, which weakens structural integrity and renders the material more susceptible to disassembly under shock conditions. Conversely, structural symmetry—including both the cage-like molecular conformation and spatial packing within the crystal lattice—was found to mitigate these destabilizing effects, effectively balancing the trade-off between energy storage and structural stability. Based on these findings, we propose a physical model that captures the essential factors driving shock initiation in cage-like polynitrocubane HEDMs, offering new insights to inform the design and application of novel advanced HEDMs.

关键词： shock stability cage-like high-energy-density materials strain energy structural symmetry strain tensor

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：