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Analytical measurement method for situation elements' dynamic characteristics

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Journal of Systems Engineering and Electronics 2017年第6期28卷 1126-1132页

作者： Huiyun Zhao Dongge Zhang Hui Meng Jiuyang Tao College of Command and Control System Army Engineering UniversityNanjing 210007China Military representative office of Taiyuan Railway Bureau Taiyuan 030013China Department of Information Operation&Command Training National Defense UniversityBeijing 100091China

This paper gives an analysis of the dynamic characteristics of situation elements(SEs) in situation awareness(SA)research. The purpose of the discussion is to understand the factors that influence SA and to help in designing the training systems to improve operators’ SA. The status function of SEs is defined and the derivative of the function represents trends of the status of SEs at each moment. Then, Fourier transform(FT) is used to give the frequency-domain function in terms of the time-domain status function. In frequency domain, the bandwidth of the status function is used as a criterion to characterize the notion of "fast" and"slow" of the change of SE’s status, which represents the dynamic characteristic of SEs. The criterion constitutes the first analytical measurement of the dynamic characteristic of SEs, which is one of the important factors that influence the SA process.

关键词： situation awareness(SA) furious transform(FT) situation elements(SEs) status value

Biodegradability and Tribological Properties of Mineral Base Oil Enhanced by Caprylic Methyl Diethanolamine Phosphate Ester

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China Petroleum Processing & Petrochemical Technology 2019年第2期21卷 103-109页

作者： Ding Jianhua Fang Jianhua Chen Boshui Liu Ping Fan Xingyu Chen Ran Department of Oil Army Logistics University Chongqing 401311 Military representative office in PetroChina Dalian Petrochemical Company Dalian 116033

The influence of synthetic caprylic methyl diethanolamine phosphate ester (abbreviated as MDEACP) on biodegradability and tribological properties of 400SN mineral base oil was studied. The biodegradability of the neat base oil and the oil doped with MDEACP was determined on a biodegradation tester. The tribological properties of the neat base oil and the oil doped with MDEACP were evaluated on a four-ball tester. Moreover, the worn surfaces were investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results revealed that MDEACP significantly promoted the biodegradation of the mineral base oil. The improvement in biodegradability was attributed to the enhanced growth and quantity of microbes by MDEACP. Furthermore, MDEACP enhanced the anti-wear properties, the friction-reducing properties, and the extreme pressure properties of the base oil. It was mainly attributed to the formation of the complex boundary lubrication film resulted from the adsorption and tribochemical reactions of MDEACP on the friction surface.

关键词： additive biodegradability friction wear extreme pressure properties

Nitrogen Mineralization from Animal Manures and Its Relation to Organic N Fractions

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Journal of Integrative Agriculture 2014年第9期13卷 2040-2048页

作者： LI Ling-ling LI Shu-tian institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences International Plant Nutrition institute (IPNI) beijing office

Laboratory aerobic incubation was conducted for 161 d to study N mineralization and the changes of organic N fractions of nine different manures（3 chicken manures, 3 pig manures and 3 cattle manures） from different farms/locations. Results indicated that significant（P〈0.01 or P〈0.001） difference existed in N mineralization between manures. The rapid N mineralization in manures occurred during 56 to 84 d of incubation. First order exponential model can be used to describe N mineralization from chicken manures and pig manures, while quadratic equation can predict mineralization of organic N from cattle manures. An average of 21, 19 and 13% added organic N from chicken manure, pig manure and cattle manure was mineralized during 161 d of incubation. Amino acid-N was the main source of N mineralization. The changes of amino acid-N together with ammonium N could explain significantly 97 and 96% of the variation in mineralized N from manured soils and manures. Amino acid-N and ammonium N are two main N fractions in determining N mineralization potential from manures. Amino acid-N contributed more to the mineralized N than ammonium N.

关键词： N mineralization N fraction pig manure chicken manure cattle manure

Real-time UAV path planning based on LSTM network

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Journal of Systems Engineering and Electronics 2024年第2期35卷 374-385页

作者： ZHANG Jiandong GUO Yukun ZHENG Lihui YANG Qiming SHI Guoqing WU Yong School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China The Flight Automatic Control Research institute of AVIC Xi’an 710065China Military representative office of Marine Wuhan Bureau in Luoyang Area Luoyang 471000China

To address the shortcomings of single-step decision making in the existing deep reinforcement learning based unmanned aerial vehicle(UAV)real-time path planning problem,a real-time UAV path planning algorithm based on long shortterm memory(RPP-LSTM)network is proposed,which combines the memory characteristics of recurrent neural network(RNN)and the deep reinforcement learning *** networks are used in this algorithm as Q-value networks for the deep Q network(DQN)algorithm,which makes the decision of the Q-value network has some *** to LSTM network,the Q-value network can use the previous environmental information and action information which effectively avoids the problem of single-step decision considering only the current ***,the algorithm proposes a hierarchical reward and punishment function for the specific problem of UAV real-time path planning,so that the UAV can more reasonably perform path *** verification shows that compared with the traditional feed-forward neural network(FNN)based UAV autonomous path planning algorithm,the RPP-LSTM proposed in this paper can adapt to more complex environments and has significantly improved robustness and accuracy when performing UAV real-time path planning.

关键词： deep Q network path planning neural network unmanned aerial vehicle(UAV) long short-term memory(LSTM)

China's top 10 breakthroughs in science and technology in 2023

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National Science Review 2024年第5期11卷 420-425页

作者：朱禾 the editorial office of NSR in beijing

Science&Technology TOP 10stories China 2023 The year of the dragon inspires our imagination with advancements in energy,space exploration and surprisingly,a new possibility of energy from space (No.9 in this list).Continuing a 30-year-long tradition,members of the Chinese Academy of Sciences (CAS) and Chinese Academy of Engineering (CAE) have selected 10 breakthroughs by domestic researchers in science and technology to represent the progress made in *** addition to 2 entries in energy and 4 in space exploration,biology and physics have also contributed 2 entries each to this year's top 10.

关键词： technology science china breakthroughs

Diurnal variation of number concentration and size distribution of ultrafine particles in the urban atmosphere of beijing in winter

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Journal of Environmental Sciences 2007年第8期19卷 933-938页

作者： SHI Zong-bo HE Ke-bin YU Xue-chun YAO Zhi-liang YANG Fu-mo MA Yong-liang MA Rui JIA Ying-tao ZHANG Jie Department of Environmental Science and Engineering Tsinghua University Beijing 100084 China. TSI Asia Pacific beijing representative Beijing 100084 China College of Earth Sciences Graduate University-of Chinese Academy of Sciences Beijing 100049 China

Number concentration and distribution of airborne particles in the size range 5.6 to 560 nm diameter were measured in beijing for a 15-d period in winter 2005. Dally average number concentrations of nucleation mode （5.6-20 um）, Aitken mode （20-100 um）, and accumulation mode （100-560 um） particles, and total particles were 17500, 32000, 4000, and 53500 cm^-3, respectively. Average particle size distribution was monomodal with a mode diameter of about 40 um at night and bimodal with mode diameters of about 10 and about 40 um during the daytime. New particle formation events, which were connected to diurnal variation of nucleation mode particles, were observed in more than half of the observation days. The events often started around 10：00-11：00 Chinese Standard Time （CST） and ended up after 3-4 h. Concentrations of Aitken and accumulation mode particles increased from midnight and reached their maxima at about 10：00 CST, and then decreased and became the lowest in the afternoon. Analysis of diurnal cycles in traffic volume and meteorological parameters revealed that the accumulation of the particles in Aitken and accumulation modes in the morning was influenced by formation of an inversion and increase in vehicle emission, and dispersion of such particles in the afternoon was associated with more effective vertical mixing and higher wind speed.

关键词： fine particles nucleation mode Aitken mode new particle formation

Open data for better science

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National Science Review 2018年第4期5卷 593-597页

作者： Weijie Zhao the NSR editorial office based in beijing

The past two decades have seen increasing interests in open *** scientists believe that the original research data should be properly organized and opened to the public and researchers throughout the world,and,once the open-data strategies are put into practice,the entire scientific research enterprise could be *** by the trend of data sharing many platforms and repositories have been ***,funding agencies and

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Pathogenic changes of community-acquired pneumonia in a children’s hospital in beijing,China before and after COVID-19 onset:a retrospective study

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World Journal of Pediatrics 2022年第11期18卷 746-752页

作者： Li-Na Zhang Ling Cao Ling-Hui Meng Department of Pulmonology Children’s HospitalCapital Institute of PediatricsBeijingChina Center for Evidence-Based Medicine Office of Science and TechnologyCapital Institute of PediatricsBeijingChina

Background This study aimed to analyze the pathogenic characteristics of community-acquired pneumonia(CAP)in a children’s hospital before and after the coronavirus disease 2019(COVID-19)pandemic and to provide testimony for preventing CAP in the *** A retrospective analysis was *** information was collected from the electronic medical record system of the hospital.A total of 2739 children were included from February 1,2019,to January 31,*** Among these 2739 patients were 1507(55.02%)males and 1232(44.98%)females;the median age was 3.84 *** were 2364 cases during the pre-COVID-19 period and 375 cases during the post-COVID-19 *** number of hospitalized children after the pandemic was 84.14%*** median age after the onset was 1.5 years younger than that before the onset(4.08 years old)(Z=−7.885,Pbacteria(50.42%)>viruses(29.57%)>fungi(3.43%).During the post-COVID-19 period,the pathogen proportions were bacteria(56.53%)>viruses(53.60%)>MP(23.47%)>fungi(3.73%).Conclusions There was a significant decrease in the number of children with CAP hospitalized after the pandemic,especially among school-age children,and the pathogen proportions of CAP with MP and IV were significantly *** inferred that CAP was effectively prevented in school-age children because of the strong mitigation measures.

关键词： Community-acquired pneumonia Comparison Coronavirus disease 2019 Pathogen

Crushing Mechanism of Spherical Tungsten Alloy Fragments Penetrate Thick Steel Plate Target

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Journal of Wuhan University of Technology(Materials Science) 2023年第2期38卷 445-450页

作者： WAN Mingming BAI Rong SHANG Zaifei WANG Yanli LIANG Jiayi LI Xue Inner Mongolian Metal Materials Research institute Yantai264003China National Defense Technology Key Laboratory of Impact Environmental Materials Yantai264003China Military representative office in Yantai Region of Army Equipment Department Yantai264003China

Against protection requirements for high-speed fragments on the ground weapons,we carried out the research work of crushing mechanism at different impact speeds ofφ8.7 mm spherical tungsten alloy,the penetration to 603 armor steel was completed by 20 mm ballistic gun,and the ANSYS/LS-DYNA software was used to complete the numerical calculation of the *** find that there are different crushing mechanisms of spherical tungsten alloy with different speeds and low speed,the crushing mechanism of fragment is mainly controlled by overall plastic deformation,shearing stripping,and squeezing at a high pressure and a high *** crushing mechanism will have a spallation phenomenon in addition to the crushing mechanism under high pressure.

关键词： spherical tungsten alloy experimental research numerical simulation crushing mechanism high pressure affected zone spallation zone