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A radar-infrared compatible broadband absorbing surface:Design and analysis

Chinese Physics B 2021年第7期30卷 605-612页

作者： Qing-Tao Yu Yuan-Song Zeng Guo-Jia Ma Aviation Key Laboratory of Science and Technology on Advanced Surface Engineering AVIC Manufacturing Technology InstituteBeijing 100024China

A radar-infrared compatible stealth surface is designed and *** modifying the radar absorbing material(RAM),the design can theoretically achieve radar-infrared compatibility and broadband radar absorption through surface patterns and structures.A transmission-line-based model(TLM)is developed to analyze the radar absorbing performance of the *** of the structure geometries is conducted aiming to maximize the-10 d B absorption bandwidth in 2–18 *** with optimized structure geometries exhibits a superior absorption bandwidth,more than twice the bandwidth of the original 1.5 mm RAM slab,while maintaining a relatively low infrared emissivity.

关键词： stealth infrared-radar compatible broadband absorbing patterned surface

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Application of associate rules mining on CGF's behavior modeling

Application of associate rules mining on CGF's behavior mode...

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International Conference on Computer Application and System Modeling

作者： Gong, Jianglei Gong, Guanghong Song, Xiao Advanced Simulation Technology Aviation Science and Technology Key Laboratory Beihang University Beijing China

ISBN: (纸本)9781424472369

In this paper, Computer Generated Forces (CGF) behavior modeling was studied from the viewpoint of associate data mining, for the large quantity of data, rules and models in its process. Because CGF behavior models data source was the combination of staticDB and dynamic data stream, the paper advanced the methods of item truncation and aim-pattern restriction. Through pretreatment, coding, searching frequent pattern, generating associate rules of the CGF behavior modeling data, then decision could be made according as these rules. Application of the two methods improves on the classical aprior algorithm, also improves efficiency of searching frequent items and credibility of CGF's decision. Finally, the application of associate rules mining in air-combat is studied in detail. As the simulation shows, comparing with the traditional matching-rule decision, associate rule mining has higher efficiency on condition with guaranteeing reliability of decision. © 2010 IEEE.

关键词： Data mining

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Research on construction and interoperability of complex distributed simulation system

Research on construction and interoperability of complex dis...

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Third Asian simulation Conference, Asiasim 2004

作者： Li, Ning Wang, Zhou Liu, Wei-Hua Peng, Xiao-Yuan Gong, Guang-Hong Advanced Simulation Technology Aviation Science and Technology Key Laboratory BUAA 100083 Beijing China

This paper presents an assumed interoperability framework of Complex Distributed simulation System (CDSS). On the basis of it, interoperability conceptual model of C4I simulation system, distributed weapon platform Modeling and simulation (M&S) system and Synthetic Natural Environment (SNE) is proposed. key technologies such as C4I modeling and simulation, SNE modeling to construct CDSS and achieve interoperability are discussed. The interoperability Data Interchange Format (DIF) based on HLA OMT, called CDSS FOM, is given and introduced, which is applied in the Attack-Defense simulation System. © Springer-Verlag Berlin Heidelberg 2005.

关键词： Distributed computer systems

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Omitted variable bias in single-pollutant epidemiological models for estimating long-term health effects of ambient fine particulate matter and ozone

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Journal of Hazardous Materials 2025年 494卷 138590页

作者： Xue, Tao Deng, Jianyu Ni, Xueqiu Kang, Ning Tong, Mingkun Li, Pengfei School of Public Health Peking University Health Science Centre Beijing100191 China Advanced Institute of Information Technology Peking University Hangzhou311215 China State Key Joint Laboratory of Environment Simulation and Pollution Control College of Environmental Sciences and Engineering Peking University Beijing100871 China Institute of Medical Technology Peking University Health Science Centre Beijing100191 China

Long-term exposure to PM2.5 and O3 is linked to various adverse health outcomes. However, many epidemiological studies on their health effects use single-pollutant models, leading to omitted variable bias (OVB). The percent bias, based on the classical OVB formula, depends on the PM2.5-O3 correlation and unobservable true effects. Data were sourced from two recent meta-analyses of the log-linear link between all-cause mortality and per-unit exposure to PM2.5 or O3. We then developed a new meta-regression method to correct biases, and its performance was verified through simulation. The OVB for PM2.5 or O3 can vary greatly from positive to negative across different spatial scales (like country, sub-national region, or city). By applying this method to 24 individual estimates, we found that a 10 μg/m³ increase in PM2.5 was linked to a 7.4 % increase in all-cause mortality risk, while O3’s association with all-cause mortality was not significant, which implies that PM2.5 must be considered in epidemiological analyses to obtain reliable effect estimates for O3. Our findings offer novel methodologies for the systematic assessment of the health effects of multiple pollutants. This contribution holds significant potential in fortifying health intervention strategies and minimizing the health risks posed by air pollution to the public. © 2025 Elsevier B.V.

关键词： Air quality

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A fast predictive-Corrective Mass Spring method in cloth simulation

A fast predictive-Corrective Mass Spring method in cloth sim...

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International Conference on Computer Application and System Modeling

作者： Zhuang, Qing Hong Ding, Ying Gong, Guang Hong Aviation Key Laboratory for Advanced Simulation Technology Beijing University of Aeronautics and Astronautics Beijing China

ISBN: (纸本)9781424472369

Physically-based cloth animation has been a hot topic to the graphics community for more than a decade. Among the physically-based models used in cloth animation, elastically deformable models have been used successfully in order to give a representation of the behavior. We present a novel PCMS (Predictive-Corrective Mass-Spring) algorithm in cloth simulation which combines the advantages of both BMS and an advanced numerical integration method, namely low computational costs and large time steps. The numerical and rendering results show that a speed-up of more than an order of magnitude over the commonly used mass-spring method while the simulation results are in agreement with real cloth behavior. In addition, the super-elastic effect will be effectively controlled without dynamic inverse constraints on deformation rates. © 2010 IEEE.

关键词： Numerical methods

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Experimental research on the mechanism of non-monotonic characteristic between curing temperature and mechanical behaviors of Kevlar/epoxy composite

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Science China(Technological Sciences) 2018年第7期61卷 1012-1020页

作者： LIU Li HU DeAn ZHANG YouMin HAN Xu State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Key Laboratory of Advanced Design and Simulation Technology for Special Equipments Ministry of Education Hunan University School of Mechanical Engineering Hebei University of Technology

An experimental procedure is conducted to investigate the mechanism of the non-monotonic characteristic between curing temperature and mechanical behaviors of the Kevlar/epoxy composite in macro and micro levels. Different specimens are fabricated at four different curing temperatures and tested with ±45° off-axis tensile loading on a universal test machine coupled with digital image correlation(DIC). Moreover, the environmental scanning electron microscope(SEM) was used to obtain the micrographs and reveal their mechanism. The tested results show that the tensile mechanical behaviors are sensitive to the curing temperature and the relationship is non-monotonic. Also, as the temperature increases, the thicknesses of the specimens are significantly enlarged. By analyzing the SEM micrographs of the matrix grooves in the damage zone and DIC strain contours, it is concluded that the non-monotonic relationship is dominated by the properties of the Kevlar/epoxy interfaces and deformation of the distorted fibers.

关键词： Kevlar/epoxy composite mechanical behavior digital image correlation SEM micrograph non-monotonic character-istic distorted fiber

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Researches on modeling and simulation of airplane infrared characteristic

Researches on modeling and simulation of airplane infrared c...

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International Conference on Computer Application and System Modeling

作者： Liu, Juan Gong, Guanghong Han, Liang Gao, Dongdong Aviation Key Laboratory for Advanced Simulation Technology Beijing University of Aeronautics and Astronautics Beijing China

ISBN: (纸本)9781424472369

One of the most important problems of airplane infrared simulation is to establish the simulation model accurately based on real-time status. This paper analyses the three main sources of infrared signatures in airplane: airplane-skin, nozzle components and exhaust plume. By reckoning environment radiation, aerodynamic heating, heat transferring and hot engine casing principle, a synthetic simulation method was used, especially a new infrared engine model for airplane was firstly proposed with airplane's working status as the input. Then atmospheric transmittance is analyzed through Modetran4 with various influential factors such as atmospheric aerosol and geometric path considered. Finally the simulation results obtained have been analyzed with respect to different work status and view angle parameters, which will have an important effect on infrared image simulation system in military simulation system. © 2010 IEEE.

关键词： Engines

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Design and implementation of rigid-flexible coupling for a half-flexible single jack nozzle

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Chinese Journal of Aeronautics 2016年第6期29卷 1477-1483页

作者： Chen Pengfei Wu Feng Xu Jinglei Feng Xudong Yang Qiao Aviation Key Laboratory of Science and Technology on Aero-Engine Altitude Simulation China Gas Turbine Establishment Aviation Engine Corporation of China Department of Power Engineering Nanjing University of Aeronautics and Astronautics

The aerodynamic design of a rigid-flexible coupling profile is the decisive factor for the flow-field quality of a supersonic free jet wind tunnel nozzle, and its mechanic dynamic features are the key for engineering implementation of continuous Mach number regulations. To fulfill the requirements of a free jet inlet/engine compatibility test within a wide simulation envelop, both uniform flow-fields of continuous acceleration and deceleration are necessary. In this paper, the aerodynamic design methods of an expansion wall and machinery implementation plan for the halfflexible single jack nozzle were researched. The profile control in nozzle flexible plate design was studied with a rigid-flexible coupling method. Design and calculations were performed with the help of numerical simulation. The technique of axial free stretching of the flexible plate was used to improve the matching performance between the designed elasticity profile and the theoretical one, and the rigid-flexible coupling structure was calibrated by wind tunnel tests. Results indicate that the flexible plate aerodynamic design method used here is effective and feasible. Via rigidflexible coupling design, the flexible plate agrees with the rigid body very well, and continuous Mach number changes can be achieved during the tests. The nozzle’s exit flow-field uniformity meets the requirements of China Military Standard(GJB).

关键词： Aerodynamic profile Flow-field quality Free jet Nozzle Rigid-flexible coupling Variable Mach number Wind tunnel

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Towards rational design of Cu-SSZ-13 catalysts with less N₂O formation in NH₃-SCR reaction: The effect of Brønsted acid sites

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Journal of Environmental Sciences (China) 2025年 157卷 546-557页

作者： Liu, Jianqi Du, Jinpeng Wang, Jingyi Han, Shichao Shan, Yulong Zhang, Yan Wu, Xuanhao Gao, Shan Yu, Yunbo Wu, Zhongbiao Shan, Wenpo He, Hong Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 China University of Chinese Academy of Sciences Beijing 100049 China State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control Ningbo Urban Environment Observation and Research Station Institute of Urban Environment Chinese Academy of Sciences Ningbo 315800 China Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai 201210 China Department of Environmental Engineering Zhejiang University Hangzhou 310058 China Zhejiang Tianlan Environmental Protection Technology Co. Ltd. Hangzhou 311202 China

Ammonia Selective Catalytic Reduction (NHs-SCR) technology has been employed to eliminate NOx from diesel engine exhaust, with Cu-SSZ-13 serving as the commercial catalyst. The greenhouse gas N2O is produced as a bypr... 详细信息

Ammonia Selective Catalytic Reduction (NHs-SCR) technology has been employed to eliminate NO_x from diesel engine exhaust, with Cu-SSZ-13 serving as the commercial catalyst. The greenhouse gas N₂O is produced as a byproduct when using Cu-SSZ-13 as the NH₃-SCR catalyst. To achieve synergistic control of pollutants and greenhouse gases in diesel engine exhaust, rational design of Cu-SSZ-13 catalysts is required. In this study, the effect of Brønsted acid sites in Cu-SSZ-13 catalysts on the formation of N₂O was investigated. Mild thermal treatment was innovatively employed to prepare Cu-SSZ-13 catalysts with different amounts of Brønsted acid sites. EPR, H₂-TPR, NH₃-TPD, NMR were utilized to determine that the Brønsted acid sites were modified while the Cu species remained unchanged. Thereby an accurate assessment of the influence of Brønsted acid sites on N₂O formation could be achieved. Our results showed that Cu-SSZ-13 with more Brønsted acid sites produced less N₂O during the NH₃-SCR reaction. In the low-temperature region, the presence of framework acid sites facilitates the decomposition of the NH₄NO₃ assisted by NO to form N₂ and H₂O, reducing the formation of N₂O. In the high-temperature region, the Brønsted acid sites promote the decomposition of NH₂NO into N₂ and H₂O. Meanwhile, the N₂O-SCR reaction can also be promoted by Brønsted acid sites, thereby decreasing N₂O emissions. This study suggests that in the future design and synthesis of Cu-SSZ-13 zeolites, attention should be paid to creating more Brønsted acid sites in Cu-SSZ-13 to reduce N₂O emissions. © 2024

关键词： Brønsted acid sites Cu-SSZ-13 zeolite N2O emission control NH3-SCR NOx abatement

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The nonlinear control of simulator of hexapod parallel mechanism

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Journal of Harbin Institute of technology(New Series) 2010年第3期17卷 393-397页

作者：潘春萍管欣卢颖梁建民 State Key Laboratory of Automobile Dynamic Simulation Jilin University Military Simulation Technology Research Institute Aviation University of Air Force

In order to enhance the innervation fidelity of simulators,a nonlinear controller is developed,which guarantees parallel mechanisms closed loop system global asymptotical stability and the convergence of posture tracking error in Cartesian space. The problems of rapid tracking under the condition of the wide range,nonlinear and variable load are solved. After the nonlinear controller is actually applied to the hexapod parallel mechanisms of simulator,the dynamic-static capabilities of motion system are tested by amplitude-frequency response and posture precision. The experimental results show that the static precision improves ten times and system output amplitude increases and the phase lag reduces with respect to the same input signal in Cartesian space in comparison with the traditional proportional and derivative (i.e. PD) controlling method in joint space. Therefore the nonlinear controller can effectively improve the dynamic-static response performance of the hexapod parallel mechanisms of simulators in Cartesian space.

关键词： simulators hexapod parallel mechanisms dynamics model nonlinear control irmervation＇ s fidelity

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