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The robustness of sparse network under limited attack capacity

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Chinese Physics B 2017年第8期26卷 577-586页

作者：王小娟宋梅金磊王珍 electronic engineering institute Beijing University of Posts and TelecommunicationsBeijing 100876China electronic engineering institute of PLA Hefei 230000China

The paper studies the robustness of the network in terms of the network structure. We define a strongly dominated relation between nodes and then we use the relation to merge the network. Based on that, we design a dominated clustering algorithm aiming at finding the critical nodes in the network. Furthermore, this merging process is lossless which means the original structure of the network is kept. In order to realize the visulization of the network, we also apply the lossy consolidation to the network based on detection of the community structures. Simulation results show that compared with six existed centrality algorithms, our algorithm performs better when the attack capacity is limited. The simulations also illustrate our algorithm does better in assortative scale-free networks.

关键词： robustness dominated relation merge lossless

A novel adaptive lateral reentry guidance algorithm with complex distributed no-fly zones constraints

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Chinese Journal of Aeronautics 2022年第7期35卷 128-143页

作者： Yudong HU Changsheng GAO Junlong LI Wuxing JING Wenxue CHEN School of Astronautics Harbin Institute of TechnologyHarbin 150001China beijing institute of electronic system engineering China Aerospace Science and Industry CorporationBeijing 100854China

Aimed at complex distributed no-fly zones avoidance problems,a novel adaptive lateral reentry guidance algorithm is ***,by introducing the improved attractive and repulsive potential fields,an improved artificial potential field method is *** with the proposed judgment criterion for whether a no-fly zone has been avoided,the proposed improved artificial potential field method effectively solves the reference heading angle determination problem under the constraints of complex distributed no-fly ***,based on the proposed no-fly zone’s threat quantitative evaluation method and the reference heading angle determined by the proposed improved artificial potential field method,the heading corridor is improved to increase its sensitivity to the threat changes of the no-fly ***,for satisfying the requirements of complex distributed no-fly zones avoidance,a novel guidance logic via improved heading corridor is proposed to update the reference heading corridor adaptively in real time according to the threat and constraint changes of the no-fly zones,and the bank reversal logic is employed to control the lateral *** simulation results for nominal and dispersed cases indicate that the proposed guidance algorithm has high robustness,stability,and applicability,and is feasible and effective to deal with the complex distributed no-fly zones avoidance problems.

关键词： Guidance strategy Heading corridor Hypersonic vehicles Improved artificial potential field Lateral reentry guidance Threat quantitative evaluation

Enhancing recommender systems by incorporating social information

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Journal of Zhejiang University-Science C(Computers and electronics) 2013年第9期14卷 711-721页

作者： Li-wei HUANG Gui-sheng CHEN Yu-chao LIU De-yi LI institute of Command Information system PLA University of Science and Technology institute of electronic system engineering

Although recommendation techniques have achieved distinct developments over the decades,the data sparseness problem of the involved user-item matrix still seriously influences the recommendation *** of the existing techniques for recommender systems cannot easily deal with users who have very few *** to combine the increasing amount of different types of social information such as user generated content and social relationships to enhance the prediction precision of the recommender systems remains a huge *** this paper,based on a factor graph model,we formalize the problem in a semi-supervised probabilistic model,which can incorporate different user information,user relationships,and user-item ratings for learning to predict the unknown *** evaluate the method in two different genres of datasets,Douban and *** indicate that our method outperforms several state-of-the-art recommendation ***,a distributed learning algorithm is developed to scale up the approach to real large datasets.

关键词： Recommender system Social information Factor graph model

Fabrication of combustion pyrotechnics for laser and electromagnetic interference shielding

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Defence Technology（防务技术） 2023年第6期24卷 140-147页

作者： Yuan-yuan Yao Shao-hua Jin Jing Huang Dong-ze Li Bo-lin Xu Xi-juan Lv Qing-hai Shu School of Materials Science and engineering Beijing Institute of TechnologyBeijing100081China School of Physics Beijing Institute of TechnologyBeijing100081China beijing institute of electronic system engineering Beijing100854China State-owned Changhong Machinery Factory Guilin541002China

The contradiction between flammability and packing density is the technical bottleneck for combustible smoke ***,polyurethane(PU)foams with flammability and resilience were prepared with polyol and isocyanate as raw materials by chemical foaming method,then compounded with metal powders,polytetrafluoroethylene(PTFE),phthalic annychide(PA),*** a certain proportion and pressed into pyrotechnic grain to obtain eco-friendly combustion aerosols with compact density of about1.15 g/cm^(3).The resulting combustion smoke agent combined the advantages of PU foam and pyrotechnic with easy ignition,large smoke production,long duration and low environmental *** transmittance of aerosols for 532 nm and 1064 nm lasers was close to 0,and the EMI SE reached up to65 d B and 35 d B in GPS band and X band,*** addition,the resulting pyrotechnic grains exhibited good mechanical strength and elasticity for sample 1:25,with a compressive strength of22 MPa and an elastic modulus of 195 *** resulting combustion smoke agent is expected to play a potential role in the field of electromagnetic damage and protection.

关键词： Smoke agent Flammability PU foam Laser masking EMI shielding

High-temperature superconducting filter using self-embedding asymmetric stepped impedance resonator with wide stopband performance and miniaturized size

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Chinese Physics B 2017年第10期26卷 477-482页

作者：王丹魏斌衡勇曹必松 State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Tsinghua University beijing institute of electronic system engineering

In this study, a novel self-embedding asymmetric stepped impedance resonator （SE-ASIR） topology is proposed. By embedding asymmetric stepped impedance resonators in themselves, circuit sizes of ASIRs can be reduced effectively, while the ability to control spurious modes of ASIRs remains. Therefore, SE-ASIRs are suitable for being used to design filters with wide stopbands and miniaturized sizes. Furthermore, the construction process of the SE-ASIR is described in detail, and an equivalent model of the SE-ASIR is proposed. For demonstration, a high-temperature superconducting bandpass filter centered at 1112 MHz is designed and fabricated. The measured result agrees well with the simulation result and shows that the out-of-band rejection is better than 60 dB up to 4088 MHz, which is about 3.7 times the center frequency. The filter circuit size is 31 mm × 13 mm or 0.28λg × 0.12λg, where g is the guided wavelength at 1112 MHz.

关键词： high-temperature superconducting bandpass filter microstrip filter wide stopband

Theoretical study of the trapping efficiency of an optical tweezers array system

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Chinese Physics B 2008年第2期17卷 726-735页

作者：李勤冯万力胡晓明曹群沙定国林家明 Department of Biomedical engineering Beijing Institute of Technology Department of Opto-electronic engineering Beijing Institute of Technology

Optical tweezers have been a valuable research tool since their invention in the 1980s. One of the most important developments in optical tweezers in recent years is the creation of two-dimensional arrays of optical traps. In this paper, a method based on interference is discussed to form gradient laser fields, which may cause the spatial modulation of particle concentration. The parameters related to the optical tweezers array are discussed in detail and simulated by the Matlab software to show the influence of important parameters on the distribution of particle concentration. The spatial redistribution of particles in a laser interference field can also be predicted according to the theoretical analysis.

关键词： optical tweezers array gradient force trapping efficiency spatial modulation

Sensors deployment optimization in multi-dimensional space based on improved particle swarm optimization algorithm

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Journal of systems engineering and electronics 2018年第5期29卷 969-982页

作者： TANG Mingnan CHEN Shijun ZHENG Xuehe WANG Tianshu CAO Hui School of Aerospace engineering Tsinghua UniversityBeijing 100084China beijing institute of electronic system engineering Beijing 100854China The Second Academy of China Aerospace Science and Industry Corporation Beijing 100854China

Sensors deployment optimization has become one of the most attractive fields in recent years. However, most of the previous work focused on the deployment problem in 2D *** to the traditional form, sensors deployment in multidimensional space has greater research significance and practical potential to satisfy the detecting needs in complex *** at solving this issue, a multi-dimensional space sensor network model is established, and the radar system is selected as an example. Considering the possible working mode of the radar system(e.g., searching and tracking), two distinctive deployment models are proposed based on maximum coverage area and maximum target detection probability in the attack direction respectively. The latter one is usually ignored in the previous *** uncovering the optimal deployment of the sensor network, the particle swarm optimization(PSO) algorithm is improved using the proposed weights determination scheme, in which the linear decreasing, the pooling strategy and the cloud theory are combined for weights updating. Experimental results illustrate the effectiveness of the proposed method.

关键词： spatial sensor optimized deployment strategy particle swarm optimization(PSO)

Depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 335-345页

作者： Feng Zhang Chenyang Zhang Linlin Wu Wei Sun Hongliang Zhang Jianhua Chen Yong Pei Songjiang Li engineering Research Center of Ministry of Education for Carbon Emission Reduction in Metal Resource Exploitation and Utilization Hunan International Joint Research Center for Efficient and Clean Utilization of Critical Metal Mineral ResourcesSchool of Minerals Processing and BioengineeringCentral South UniversityChangsha 410083China State Key Laboratory of Mineral Processing Beijing General Research Institute of Mining&MetallurgyBeijing 100160China Hunan Provincial Key Laboratory of Micro&Nano Materials Interfaces Science College of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083China School of Resources Environment and MaterialsGuangxi UniversityNanning 530004China Department of Chemistry Xiangtan UniversityXiangtan 411105China China Railway Resource Group Co.Ltd Beijing 102300China

The depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite still lacked in-depth ***,the depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite was further systematically investigated with experiments and density functional theory(DFT)*** X-ray photoelectric spectroscopy(XPS)results,DFT calculation results,and frontier molecular orbital analysis indicated that sulfite ions were difficult to be adsorbed on sphalerite surface,suggesting that sulfite ions achieved depression effects on sphalerite through other non-adsorption ***,the oxygen content in the surface of sphalerite treated with sulfite ions in creased,which enhanced the hydrophilicity of the sphalerite and further increased the difference in hydrophilicity between sphalerite and ***,sulfite ions were chelated with lead ions to form PbSO_(3)in *** hydrophilic PbSO_(3)was more easily adsorbed on sphalerite than *** interaction between sulfite ions and lead ions could effectively inhibit the activation of *** addition the UV spectrum showed that after adding sulfite ions,the peak of perxanthate in the sphalerite treated xanthate solution was significantly stronger than that in the galena with xanthate solution,indicating that xanthate interacted more readily with sulfite ions and oxygen mo lecules within the sphalerite system,leading to the formation of ***,sulfite ions hardly depressed the flotation of ga lena and could promote the flotation of galena to some *** study deepened the understanding of the depression mechanism o sulfite ions on sphalerite and Pb^(2+)activated sphalerite.

关键词： sphalerite galena sulfite ion density functional theory depression mechanism

Solution of Electromagnetic Wave in Time-Varying Media in Two-Dimensional Space

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Chinese Physics Letters 2006年第3期23卷 595-598页

作者：陈丙康张颖高本庆 Department of electronic engineering Beijing Institute of Technology Beijing 100081

The analytical solution of gradual change media in two-dimensional free space is studied. Using separation of variables, the solution of electromagnetic wave in time-varying media, which is an exponential function of time, is derived in two-dimensional space. The rationality of the solution is verified indirectly. According to the solution, the figures of the wave are depicted. Based on these figures, the character of the wave in time-varying media is obtained, which shows frequency shift and changes of phase velocity and amplitude.

关键词： PROPAGATION