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Combat situation suppression of multiple UAVs based on spatiotemporal cooperative path planning

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Journal of Systems Engineering and Electronics 2023年第5期34卷 1191-1210页

作者： hu Lei yi Guoxing NAN yi WANG Hao School of Astronautics Harbin Institute of TechnologyHarbin 150001China

Aiming at the suppression of enemy air defense(SEAD)task under the complex and complicated combat sce-nario,the spatiotemporal cooperative path planning methods are studied in this *** major research contents include opti-mal path points generation,path smoothing and cooperative *** the path points generation part,the path points availability testing algorithm and the path segments availability testing algorithm are designed,on this foundation,the swarm intelligence-based path point generation algorithm is utilized to generate the optimal *** the path smoothing part,taking ter-minal attack angle constraint and maneuverability constraint into consideration,the Dubins curve is introduced to smooth the path *** cooperative rendezvous part,we take esti-mated time of arrival requirement constraint and flight speed range constraint into consideration,the speed control strategy and flight path control strategy are introduced,further,the decoupling scheme of the circling maneuver and detouring maneuver is designed,in this case,the maneuver ways,maneu-ver point,maneuver times,maneuver path and flight speed are ***,the simulation experiments are conducted and the acquired results reveal that the time-space cooperation of multiple unmanned aeriel vehicles(UAVs)is effectively real-ized,in this way,the combat situation suppression against the enemy can be realized in SEAD scenarios.

关键词： heterogeneous unmanned aeriel vehicles(UAVs) situation suppression coope rative rendezvous maneuver strategy multiple constraints

Rainfall occurrence and its relation to flood damage in China from 2000 to 2015

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Journal of Mountain Science 2018年第11期15卷 2492-2504页

作者： WEI Li hu kai-heng hu Xu-dong Key Laboratory of Mountain Hazards and Earth Surface Processes Chinese Academy of Sciences Chengdu 610041China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China University of Chinese Academy of Sciences Beijing 100049 China

China is highly susceptible to flood disasters and subjected to great damage every ***, the flood frequency has exhibited an increasing trend in recent years. Most flood events,including flash floods and river flood, are induced by rainfall. This study investigates annual variations of rainfall occurrence over China during the period from 2000 to 2015 at the national and regional scale using daily rainfall data from the Tropical Rainfall Measuring Mission. The Mann-Kendall test is performed for trend detection, and statistical data of flood damage published by China's government,including destroyed crop area, damaged buildings,direct economic loss, percentage of GDP(gross domestic product), and death toll are correlatively analysed with rainfall occurrences. The results show that storm rain events show the greatest variation among three rainfall types(moderate rain, heavy rain and storm rain). The variation coefficients of rainfall over Northeast China, North China, and Northwest China are the highest, whereas that for Southwest China is the smallest. Moderate rain, heavy rain over Central China, and moderate rain over Southwest China exhibits decreasing trends, whereas the remaining exhibit increasing trends. The correlation between the rainfall occurrences and these flood damage indices at the national scale shows that only direct economic loss has a strong positive correlation with rainfall occurrences, and the other indices have weaker correlations. The correlation is strong in three north regions, except for death toll in Northwest China. In contrast, the correlation between flood damage and rainfall is weak in East China, Central China, Southwest China, and South China. Overall,death toll is strongly correlated with the number of damaged buildings, implying that flood fatalities in China are likely associated with building collapse, and are dominated by specific extreme events. This study can provide a scientific reference for flood management in

关键词： Flood damage Rainfall occurrence Storm rainfall Coefficient of variation

Influence of a multi-step process on the thickness reduction error of sheet metal in a flexible rolling process

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International Journal of Minerals,Metallurgy and Materials 2019年第1期26卷 76-85页

作者： yi Li Ming-zhe Li kai Liu Dieless Forming Technology Center Roll Forging Institute Jilin University College of Materials Science and Engineering Jilin University

Flexible rolling is a forming process based on thickness reduction, and the precision of thickness reduction is the key factor affecting bending deformation. The major purpose of the present work is to solve the problem of bending deformation error caused by insufficient thickness reduction. Under the condition of different rolling reductions with the same sheet thickness and the same thickness reduction with different sheet thicknesses, the thickness reduction error of sheet metal is analyzed. In addition, the bending deformation of sheet metal under the same conditions is discussed and the influence of the multi-step forming process on the thickness reduction error is studied. The results show that, under the condition of the same sheet thickness, the thickness reduction error increases with increasing rolling reduction because of an increase in work hardening. As rolling reduction increases, the longitudinal bending deformation decreases because of the decrease of the maximum thickness difference. Under the condition with the same thickness reduction, the thickness reduction error increases because of the decrease of the rolling force with increasing sheet thickness. As the sheet thickness increases, the longitudinal bending deformation increases because of the increase in the maximum thickness difference. A larger bending deformation is divided into a number of small bending deformations in a multi-step forming process, avoiding a sharp increase in the degree of work hardening; the thickness reduction error is effectively reduced in the multi-step forming process. Numerical simulation results agree with the results of the forming experiments.

关键词： flexible rolling convex surface numerical simulation thickness reduction error multi-step forming process

Synthesis of mesoporous silica microspheres by a spray-assisted carbonation microreaction method

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Particuology 2020年第3期18卷 173-180页

作者： Chunli Han Yunpeng hu kai Wang Guangsheng Luo The State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

A novel spray-assisted carbonation microreaction method for the synthesis of mesoporous silica microspheres is *** synthetic process comprises the preparation of a silica sol via a carbonation reaction,rapid gelation at high temperature,and subsequent rapid solvent evaporation by spray *** carbonation microreaction was conducted in a membrane dispersion microreactor,in the presence of sodium silicate and carbon dioxide *** as-synthesized silica microspheres exhibit a uniform mesostructure,excellent dispersity,and a narrow particle size distribution,with average diameters of 1-2 μm,Brunauer-Emmett-Teller surface areas of 300-1149m2/g,and total pore volumes of 0.21-1.82 cm3/*** low concentrations of the silicate species and well-controlled silica condensation rates are responsible for the formation of the observed spherical *** synthetic process is of significant practical importance as a result of using low-cost raw materials,and because of the excellent controllability and process stability ***,this rapid and flexible method may be extended to the synthesis of various silica materials and their composites.

关键词： Silica microspheres Mesoporous Carbonation method Spray drying Microreaction

Recent progress on synthesis of ZIF-67-based materials and their application to heterogeneous catalysis

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Green Energy & Environment 2022年第1期7卷 3-15页

作者： Chongxiong Duan yi Yu Han hu State Key Laboratory of Heavy Oil Processing College of Chemical EngineeringInstitute of New EnergyChina University of Petroleum(East China)Qingdao266580China School of Materials Science and Hydrogen Engineering Foshan UniversityFoshan528231China School of Chemistry and Chemical Engineering South China University of TechnologyGuangzhou510640China

In recent years,an increasing amount of interest has been dedicated to the synthesis and application of ZIF-67-based materials due to their exceptionally high surface area,tunable porosity,and excellent thermal and chemical *** review summarizes the latest strategies of synthesizing ZIF-67-based materials by exploring the prominent ***,the recent progress in the applications of ZIF-67-based materials in heterogeneous catalysis,including catalysis of the redox reactions,addition reactions,esterification reactions,Knoevenagel condensations,and hydrogenation-dehydrogenation reactions,has been elaborately ***,we end this work by shedding some light on the large-scale industrial production of ZIF-67-based materials and their applications in the future.

关键词： Zeolitic imidazolate framework-67 Synthetic methods Heterogeneous catalysis

A sparse algorithm for adaptive pruning least square support vector regression machine based on global representative point ranking

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Journal of Systems Engineering and Electronics 2021年第1期32卷 151-162页

作者： hu Lei yi Guoxing huANG Chao School of Astronautics Harbin Institute of TechnologyHarbin 150001China

Least square support vector regression(LSSVR)is a method for function approximation,whose solutions are typically non-sparse,which limits its application especially in some occasions of fast *** this paper,a sparse algorithm for adaptive pruning LSSVR algorithm based on global representative point ranking(GRPR-AP-LSSVR)is *** first,the global representative point ranking(GRPR)algorithm is given,and relevant data analysis experiment is implemented which depicts the importance ranking of data ***,the pruning strategy of removing two samples in the decremental learning procedure is designed to accelerate the training speed and ensure the *** removed data points are utilized to test the temporary learning model which ensures the regression ***,the proposed algorithm is verified on artificial datasets and UCI regression datasets,and experimental results indicate that,compared with several benchmark algorithms,the GRPR-AP-LSSVR algorithm has excellent sparsity and prediction speed without impairing the generalization performance.

关键词： least square support vector regression(LSSVR) global representative point ranking(GRPR) initial training dataset pruning strategy sparsity regression accuracy

Green Therapy of Cancer:A Promising Grope for Anticancer Strategy by Modern Chinese Medicine

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Chinese Journal of Integrative Medicine 2018年第8期24卷 568-572页

作者： ZHOU Tian hu kai-wen Department of Oncology Dongfang Hospital Affiliated to Beijing University of Chinese Medicine

In 2003, a 61-year old highly respected director of the Surgery Department of Dongfang Hospital Affiliated to Beijing University of Chinese Medicine was diagnosed as advanced lung cancer, moderately differentiated adenocarcinoma, coverinqmore than two thirds of the thoracic aorta, multiple mediastinal nodal metastases, pleural effusion ＂Only 3 months could be expected＂, a cruel fact came out after deliberation of many seasoned medical specialists. In the whole career of this surgery professor, he used the lancet as his weapon to save lives. But this time after weighing the pros and cons again and again, he required a ＂tender＂ plan with no lancet.

关键词： CGT In Green Therapy of Cancer:A Promising Grope for Anticancer Strategy by Modern Chinese Medicine QOL

Instability of thermocapillary flow in liquid layers under microgravity

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Science China(Physics,Mechanics & Astronomy) 2012年第4期55卷 684-692页

作者： XUN Bo LI kai hu WenRui Key Laboratory of Microgravity(National Microgravity Laboratory) Institute of MechanicsChinese Academy of SciencesBeijing 100190China

The instability of the thermocapillary flow in liquid layers is studied in the present paper using the linear stability *** on the two-dimensional steady flow state,the three-dimensional disturbance with a wave number in the spanwise direction is *** effects of the aspect ratio and free surface shape of the liquid layer on the flow instability are studied,and the results are compared with the case with the two-dimensional disturbance.

关键词： thermocapillary convection flow instability numerical simulations of chaotic systems

A debris-flow impact pressure model combining material characteristics and flow dynamic parameters

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Journal of Mountain Science 2018年第12期15卷 2721-2729页

作者： TANG Jin-bo hu kai-heng Key Laboratory of Mountain Hazards and Surface Process Chinese Academy of SciencesChengdu 610041China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China

Impact force is a crucial factor to be considered in debris-resisting structure design. The impact of debris flow against a structural barrier depends not only on the flow dynamics but also on the barrier material. Based on the structural vibration equation and energy conservation law, a simple model for calculating debris-flow impact pressure is proposed, which includes the mechanical impedance of the material, debris-flow velocity and Froude number. Twenty-five impact tests have been conducted using different kinds of materials: steel, black granite, white granite, marble and polyvinyl chloride(PVC) board, and the ratio of the maximum impact time to the vibration period of the structure is determined for the model. It is found that the ratio's square root shows a linear relationship with the material solid Froude number. This indicates that the impedance of the structures plays an important role in the flow-barrier interaction. Moreover, the debrisflow impact force is found to decrease with the travel time of the elastic stress wave though the structures.

关键词： Debris flows Impact pressure Dynamical responses Mechanical impedance