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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)

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

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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

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

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

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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

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

Energetic Materials Frontiers

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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

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

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

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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

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

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

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International Workshop on Metamaterials

作者： Wang Ming-liang Zhang Sheng-jun Liu Jia-qi Liang Wei Liu Xue-mei X. W. Liang National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical Beijing China

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.

关键词： Frequency selective surfaces Random access memory Reflectivity Resonant frequency Arrays Substrates

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Effects of discharge types on plasma collisional absorption of electromagnetic waves

Effects of discharge types on plasma collisional absorption ...

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International Workshop on Metamaterials

作者： Runhui Wu Shengjun Zhang Jiaqi Liu Aimin Ren Gang Meng Wei Liang Xuemei Liu National Key Laboratory of Science and Technology on test physics & numerical mathematical Beijing China

In this paper, the collisional absorption mechanism of electromagnetic wave in plasma of different types is studied with numerical methods. The collision frequency and electromagnetic wave which is made by RF discharge in the obturator or DC discharge around the opening space. The computation models are founded for calculating the absorption by the plasma. The FDTD method is presented for simulating the collisional absorption of electromagnetic wave power for one-dimensional homogeneous/inhomogeneous plasma. The emulational results illustrate that there are two conclusions: 1) the homogeneous plasma which is produced by RF discharge in the obturator on collisional absorption of electromagnetic wave can absorb the energy of electromagnetic wave effectively in the finite bandwidth; 2) the inhomogeneous plasma which is produced by DC discharge around the opening space can absorb the energy of electromagnetic wave availably both in the wide bandwidth and from low-frequency to high-frequency.

关键词： Plasmas Discharges (electric) Absorption Radio frequency Nonhomogeneous media Electromagnetic scattering Attenuation

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Impacts of Cumulus Momentum Transport on MJO Simulation

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Advances in Atmospheric sciences 2009年第5期26卷 864-876页

作者：凌健李崇银贾小龙 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Graduate University of the Chinese Academy of Sciences Institute of Meteorology PLA University of Science and Technology National Climate Center

Vertical cumulus momentum transport is an important physical process in the tropical atmosphere and plays a key role in the evolution of the tropical atmospheric system. This paper focuses on the impact of the vertical cumulus momentum transport on Madden-Julian Oscillation （MJO） simulation in two global climate models （GCMs）. The Tiedtke cumulus parameterization scheme is applied to both GCMs [CAM2 and Spectral Atmospheric general circulation Model of LASG/IAP （SAMIL）]. It is found that the MJO simulation ability might be influenced by the vertical cumulus momentum transport through the cumulus parameterization scheme. However, the use of vertical momentum transport in different models provides different results. In order to improve model＇s MJO simulation ability, we must introduce vertical cumulus momentum transport in a more reasonable way into models. Furthermore, the coherence of the parameterization and the underlying model also need to be considered.

关键词： Madden Julian Oscillation vertical cumulus momentum transport propagation characteristics

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Performance analysis of one-step prediction-based cognitive jamming in jammer-radar countermeasure model

Performance analysis of one-step prediction-based cognitive ...

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IET International Radar Conference 2018, IRC 2018

作者： Gao, Lu Liu, Li Cao, Yang Wang, Shangyue You, Shixun National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China DFH Satellite Co. Ltd Beijing China Harbin Engineering University 145 Nantong Street Nangang District Harbin China

Strong adaptive radar, such as cognitive radar (CNR), can perform various missions while ensuring its own security in electronic warfare, via detecting environments and changing the radar parameters in real time. Unfortunately, most of the current military countermeasures, such as jamming-based electronic countermeasures, have rarely been related to jamming for CNR. Since the behaviours of radar in the traditional design of the jammer-radar scenario are always static, it is easy to create a subjective or local optimal jamming effect. In order to dynamically analyse the execution process of a complete jamming radar mission, this work establishes an equivalent attack-defence game in which the radar is regarded as a defence decision agent, and the jammer is an attack decision agent. The attributes of the game's players, the rules of the game, and the conditions for the end of the game are set clearly by setting reasonable parameters. After searching for antagonism strategies by exhaustive method, it can be found that the survivability of the predictive cognitive jamming is much stronger than that of the normal jamming based on real-time sampling data of radars. This conclusion is demonstrated through a 1 ms simulation of the game process. © This is an open access article published by the IET under the Creative Commons Attribution License (http://***/licenses/by/3.0/)

关键词： Jamming

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Application of Graphic Electromagnetic Computing in Electrically Large Scale Composite Target Scattering

Application of Graphic Electromagnetic Computing in Electric...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Lu Gao Ning Fang Mingliang Wang Jiaqi Liu Yanan Li Runhui Wu Yinfang Xu National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China Academy of electronic information engineering Beihang University Beijing China National Key Laboratory of Science and Technology on Test Physics Beijing China

The radar cross section(RCS) calculation model of electrically large-scale composite target is established by combining graphic electromagnetic computing(GRECO) with high-frequency optical approximation and physical diffraction. Using different illumination modes, the normal vector at each point on the target surface is obtained, and the total scattering field of the target is acquired by the coherent superposition of the scattering field and the diffraction field at each point on the target surface.

关键词： Graphics Optical diffraction Laser radar Diffraction Computational modeling Lighting Optical computing

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