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Enhanced propellant performance via environmentally friendly curable surface coating

Defence Technology（防务技术） 2017年第3期13卷 131-142页

作者： Thelma Manning Jeffrey Wyckoff Kenneth Klingaman Viral Panchal Eugene Rozumov John Bolognini ming wang young Subhash Patel US Army RDECOM ARDEC Picatinny Arsenal Polymer Processing Institute

Surface coating of granular propellants is widely used in a multiplicity of propellants for small, medium and large caliber ammunition. All small caliber ball propellants exhibit burning progressivity due to application of effective deterrent coatings. Large perforated propellant grains have also begun utilizing plasticizing and impregnated deterrent coatings with the purpose of increasing charge weights for greater energy and velocity for the projectile. The deterrent coating and impregnation process utilizes volatile organic compounds(VOCs) and hazardous air pollutants(HAPs) which results in propellants that need to be forced air dried which impacts air quality. Propellants undergo temperature fluctuations during their life. Diffusion coefficients vary exponentially with variations in temperature. A small temperature increase can induce a faster migration, even over a short period of time, which can lead to large deviations in the concentration. This large concentration change in the ammunition becomes a safety or performance liability. The presence of both polymeric deterrents and nitroglycerin(NG) in the nitrocellulose matrix and organic solvents leads to higher diffusion rates. This results in continued emissions of VOCs and HAPs. Conventional polymers tend to partition within the propellant matrix. In other words,localized mixing can occur between the polymer and underlying propellant. This is due to solvent induced softening of the polymer vehicle over the propellant grain. In effect this creates a path where migration can occur. Since nitrate esters, like NG, are relatively small, it can exude to the surface and create a highly unstable and dangerous situation for the warfighter. Curable polymers do not suffer from this partitioning due to "melting" because no VOC solvents are present. They remain surface coated. The small scale characterization testing, such as closed bomb testing, small scale sensitivity, thermal stability,and chemical compatibility, will

关键词：推进剂性能表面涂层可固化环境友好挥发性有机化合物有害空气污染物大口径弹药硝酸纤维素

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Constrained Multi-Objective Optimization With Deep Reinforcement Learning Assisted Operator Selection

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 919-931页

作者： Fei ming Wenyin Gong Ling wang Yaochu Jin the School of Computer Science China University of GeosciencesWuhan 430074China the Department of Automation Tsinghua UniversityBeijing 100084China the Faculty of Technology Bielefeld UniversityNorth Rhine-Westphalia33619 BielefeldGermany

Solving constrained multi-objective optimization problems with evolutionary algorithms has attracted considerable *** constrained multi-objective optimization evolutionary algorithms(CMOEAs)have been developed with the use of different algorithmic strategies,evolutionary operators,and constraint-handling *** performance of CMOEAs may be heavily dependent on the operators used,however,it is usually difficult to select suitable operators for the problem at ***,improving operator selection is promising and necessary for *** work proposes an online operator selection framework assisted by Deep Reinforcement *** dynamics of the population,including convergence,diversity,and feasibility,are regarded as the state;the candidate operators are considered as actions;and the improvement of the population state is treated as the *** using a Q-network to learn a policy to estimate the Q-values of all actions,the proposed approach can adaptively select an operator that maximizes the improvement of the population according to the current state and thereby improve the algorithmic *** framework is embedded into four popular CMOEAs and assessed on 42 benchmark *** experimental results reveal that the proposed Deep Reinforcement Learning-assisted operator selection significantly improves the performance of these CMOEAs and the resulting algorithm obtains better versatility compared to nine state-of-the-art CMOEAs.

关键词： Constrained multi-objective optimization deep Qlearning deep reinforcement learning(DRL) evolutionary algorithms evolutionary operator selection

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Microstructure and property of laser additive manufactured alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si after aged at different temperatures

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Rare Metals 2024年第5期43卷 2275-2281页

作者： Guo-Chao Li Xu Cheng Hua-ming wang National Engineering Laboratory of Additive Manufacturing for Large Metallic Components and Engineering Research Center of Ministry of Education on Laser Direct Manufacturing for Large Metallic Components School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

The solid solution and aging treatment for conventional manufacturing processes might not be suitable for laser additive manufactured titanium alloys due to the different lamellar *** this study,the influence of aging temperatures(600,700 and 800°C)on microstructure and mechanical properties of titanium alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si was *** results indicate that after solid solution treatment at 970°C followed by water quenching,the alloy mainly consists of coarsening lamellar a phase in martensite α' *** at 600°C will not change the size of primary lamellar α phase but lead to huge amount of secondary a phases(α_(s))generating with very fine *** increasing the aging temperature,the number of α_(s) decreases but with coarsened *** aged at 800°C,the width of the asphase reaches 350 nm,almost 7 times wider than that aged at 600°*** changing size of α_(s) obviously influences the property of the *** fine α_(s) leads to high strength and microhardness but low plasticity,and specimen aged at 700°C with suitable assize has the best comprehensive properties.

关键词： α+βtitanium alloy Laser additive manufacturing Solid solution and aging treatment Microstructure Room temperature tensile property

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紧急制动工况下电磁式磁轨制动器极靴磨损计算方法

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交通运输工程学报 2017年第1期17卷 82-92页

作者：陈士安杨鑫姚明王胜 KIM young-bae 浙江水利水电学院机械与汽车工程学院浙江杭州310018 江苏大学汽车与交通工程学院江苏镇江212013 全南国立大学机械工程系光州61186

为了预测极靴服务寿命,确保制动可靠,通过磨损过程、制动过程、制动器/钢轨温度场的建模与仿真,计算了高速列车紧急制动过程中电磁式磁轨制动器极靴磨损量;建立了考虑速度与温度的Archard磨损模型和CRH2列车紧急制动过程的动力学模型,... 详细信息

为了预测极靴服务寿命,确保制动可靠,通过磨损过程、制动过程、制动器/钢轨温度场的建模与仿真,计算了高速列车紧急制动过程中电磁式磁轨制动器极靴磨损量;建立了考虑速度与温度的Archard磨损模型和CRH2列车紧急制动过程的动力学模型,计算了电磁式磁轨制动器样机全程参与制动时的空气制动力、电磁制动力、制动减速度、紧急制动能量分配系数、瞬时速度和制动距离等时变参数;分析了紧急制动时电磁式磁轨制动器-钢轨-大气间的热量传递,基于Fluent软件建立了制动器/钢轨的三维温度场模型,根据制动过程时变参数获取温度场热流密度和散热加载条件;针对CRH2列车行驶速度为250km·h-1的紧急制动工况,计算了制动器极靴的磨损量。计算结果表明:在制动过程中,钢轨顶部温度随着与制动器的接触状态变化呈波动变化,在距离有效制动起点1 620m处,钢轨与8号电磁式磁轨制动器接触结束时,温度达到最大值570.76℃;CRH2列车同侧8个制动器极靴底部在制动时间为24.5s时温度达到最大值,从前到后依次为1 022.6℃、1 037.7℃、1 045.3℃、1 052.8℃、1 085.7℃、1 100.9℃、1 109.2℃、1 124.4℃,极靴磨损量从前到后依次为207.4、208.7、210.0、210.7、212.1、213.4、214.4、215.5g。可见,制动器工作会使钢轨产生热量积累,导致列车运行方向后面的电磁式磁轨制动器极靴温度较高,磨损量较大。

关键词：车辆工程电磁式磁轨制动器时变参数极靴磨损紧急制动磨损模型温度场仿真

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Tailoring Classical Conditioning Behavior in TiO_(2) Nanowires:ZnO QDs-Based Optoelectronic Memristors for Neuromorphic Hardware

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Nano-Micro Letters 2024年第7期16卷 265-280页

作者： Wenxiao wang Yaqi wang Feifei Yin Hongsen Niu young-Kee Shin Yang Li Eun-Seong Kim Nam-young Kim School of Information Science and Engineering University of JinanJinan 250022People’s Republic of China RFIC Centre NDAC CentreKwangwoon UniversityNowon-guSeoul 139-701South Korea Department of Electronics Engineering Kwangwoon UniversityNowon-GuSeoul 139-701South Korea School of Microelectronics Shandong UniversityJinan 250101People’s Republic of China Department of Molecular Medicine and Biopharmaceutical Sciences Seoul National UniversitySeoul 08826South Korea

Neuromorphic hardware equipped with associative learn-ing capabilities presents fascinating applications in the next generation of artificial ***,research into synaptic devices exhibiting complex associative learning behaviors is still ***,an optoelec-tronic memristor based on Ag/TiO_(2) Nanowires:ZnO Quantum dots/FTO was proposed and constructed to emulate the biological associative learning *** implementation of synaptic behaviors,including long and short-term plasticity,and learning-forgetting-relearning behaviors,were achieved in the device through the application of light and electrical *** the optoelectronic co-modulated characteristics,a simulation of neuromorphic computing was conducted,resulting in a handwriting digit recognition accuracy of 88.9%.Furthermore,a 3×7 memristor array was constructed,confirming its application in artificial visual *** importantly,complex biological associative learning behaviors were emulated by mapping the light and electrical stimuli into conditioned and unconditioned stimuli,*** training through associative pairs,reflexes could be triggered solely using light ***-sively,under specific optoelectronic signal applications,the four features of classical conditioning,namely acquisition,extinction,recovery,and generalization,were elegantly *** work provides an optoelectronic memristor with associative behavior capabilities,offering a pathway for advancing brain-machine interfaces,autonomous robots,and machine self-learning in the future.

关键词： Artificial intelligence Classical conditioning Neuromorphic computing Artificial visual memory Optoelectronic memristors ZnO Quantum dots

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Comparison of Measurements for Enhanced Diffusion Problem in Chemical Reaction Systems

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Chinese Journal of Chemistry 2024年第14期42卷 1659-1664页

作者： Ah-young Jee Ziyang Wen Huan wang Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringBeijing Key Laboratory of Polymer Chemistry&Physics of Ministry of EducationPeking UniversityBeijing100871 China

The problem of molecular diffusion in the soup of chemical reactions attracts mounting interest across fields ranging from chemistry to biophysics to material *** reactions involve bond breakup and formation,whose time scale is typically on the orders of fs to ps,while molecular diffusion occurs at time scales ofμs to *** two processes are often considered orthogonal,given the vastly different *** serial results show that the enzyme's diffusion is enhanced in a substrate-dependent manner,which was further extended to small molecule reaction systems,challenging this classical ***,the results from different groups using different techniques do not quantitatively agree,and a general mechanism is yet to be *** summarize experimental studies on diffusion problems and seek to reconcile the interpretation with understanding the limits of measurement tools and the chemical nature of reaction *** molecular diffusion in chemical reactions will provide fresh thoughts in designing chemical systems such as molecular machines that harvest work at the nanoscale in a controllable manner.

关键词： Molecular diffusion Chemical reactions Enzyme reactions Active matter Diffusion measurements Single-molecule studies Fluorescence Time-resolved spectroscopy

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Adaptive security control of time-varying constraints nonlinear cyber-physical systems with false data injection attacks

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Journal of Control and Decision 2024年第1期11卷 50-59页

作者： Yue-ming wang Yuan-Xin Li Department of Science Liaoning University of TechnologyJinzhouPeople’s Republic of China

In this article,an adaptive security control scheme is presented for cyber-physical systems(CPSs)suffering from false data injection(FDI)attacks and time-varying state ***,an adaptive bound estimation mechanism is introduced in the backstepping control design to mitigate the effect of FDI ***,to solve the unknown sign time-varying statefeedback gains aroused by the FDI attacks,a type of Nussbaum function is employed in the adaptive security ***,by constructing a barrier Lyapunov function,it can be ensured that all signals of controlled system are bounded and the time-varying state constraints are not ***,the provided simulation examples demonstrate the effectiveness of the proposed controller.

关键词： Neural networks backstepping technology false data injection(FDI)attacks nonlinear cyber-physical systems controls

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A Simple-Prepared and Multi-Reusable Adhesive Based on Epoxy Vitrimer

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Chinese Journal of Polymer Science 2024年第10期42卷 1589-1594,I0015页

作者： Yu-Ting wang Huan Liang Yen Wei Jian-Long wang Xiang-ming He Yang Yang Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing100084China The Key Laboratory of Bioorganic Phosphorus Chemistry&Chemical Biology(Ministry of Education) Department of ChemistryTsinghua UniversityBeijing100084China

Adhesives play an important role in modern society's production and daily *** robust and sustainable adhesives remains a great *** we report a sustainable epoxy-vitrimer adhesive with high adhesive strength(about 10 MPa)and reusability(82%strength after 3 times).This adhesive can be fabricated from commercially available products through a straightforward hot-pressing method without the need of *** adhesive process is also simple,requiring only 30 min at 180℃.In addition,the vitrimer adhesive has the advantages of both erasability for reuse and excellent water *** work provides a facile strategy to fabricate high-strength adhesive that ensures reusability,recyclability,low cost of raw materials,and simple processing ***,it expands the range of potential applications for epoxy vitrimers.

关键词： Epoxy Vitrimer Adhesive Reusable Sustainable

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Enhanced remediation of chlorpyrifos-contaminated soil by immobilized strain Bacillus H27

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Journal of Environmental Sciences 2024年第10期144卷 172-184页

作者： Changrui Liu Shengfang Wen Shuhan Li Yu Tian Lanjun wang Lusheng Zhu Jun wang young Mo Kim Jinhua wang National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources Key Laboratory of Agricultural Environment in Universities of ShandongCollege of Resources and EnvironmentShandong Agricultural UniversityTaian 271018China Department of Civil and Environmental Engineering Hanyang UniversitySeongdong-guSeoul 04763Korea

Chlorpyrifos is a pesticide widely used in agricultural production with a relatively long residual half-life in *** the problem of residual chlorpyrifos is of universal *** this study,rice hull biochar was used as an immobilized carrier to prepare the immobilized strain H27 for the remediation of chlorpyrifos-contamination *** microorganisms after remediation were investigated by ecotoxicological *** immobilized strain H27 had the highest removal rate of chlorpyrifos when 10%bacterial solution was added to the liquid medium containing 0.075-0.109 mm diameter biochar cultured for 22 *** study on the removal of chlorpyrifos by immobilized strain H27 showed that the initial concentration of chlorpyrifos in solution was 25mg/L,and the removal rate reached 97.4%after 7 days of *** the soil,the removal rate of the immobilized bacteria group increased throughout the experiment,which was significantly higher than that of the free bacteria and biochar treatment *** Biolog-ECO test,T-RFLP and RT-RCR were used to study the effects of the soil microbial community and nitrogen cycling functional genes during chlorpyrifos *** was found that ICP group had the highest diversity index among the four treatment *** microflora of segment containing 114 bp was the dominant bacterial community,and the dominant microflora of the immobilized bacteria group was more evenly *** influence of each treatment group on ammonia-oxidizing bacteria(AOB)was greater than on ammonia-oxidizing archaea(AOA).This study offers a sound scientific basis for the practical application of immobilized bacteria to reduce residual soil pesticides.

关键词： Chlorpyrifos Immobilized microorganisms Soil remediation Soil microorganism

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Patterns and drivers of seasonal water sources for artificial sand-fixing plants in the northeastern Mu Us sandy land,Northwest China

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Pedosphere 2024年第1期34卷 63-77页

作者： Yanwu PEI Laiming HUANG ming'an SHAO Jiao wang Yinglong ZHANG Yellow River Delta Modern Agricultural Engineering Laboratory Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Natural Resources and Environment Northwest Agriculture and Forestry UniversityYangling 712100China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences of Chinese Academy of SciencesBeijing 100085China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Shenmu Ecological Association Shenmu 719399China

Understanding plant water-use patterns is important for improving water-use efficiency and for sustainable vegetation restoration in arid and semi-arid regions. However, seasonal variations in water sources and their control by different sand-fixing plants in water-limited desert ecosystems remain poorly understood. In this study, stable isotopic ratios of hydrogen(δ^(2)H) and oxygen(δ^(18)O) in precipitation, soil water, groundwater, and xylem water were determined to document seasonal changes in water uptake by three representative plant species(Pinus sylvestris var. mongolica Litv., Amygdalus pedunculata Pall., and Salix psammophila) in the northeastern Mu Us sandy land, Northwest China. Based on the depth distribution and temporal variation of measured gravimetric soil water content(SWC), the soil water profile of the three species stands was divided into active(0.01 g g^(-1)45%) layers. Annually, P. sylvestris, A. pedunculata, and S. psammophila obtained most water from deep(59.2%±9.7%, moist layer and groundwater),intermediate(57.4%±9.8%, stable and moist layers), and shallow(54.4%±10.5%, active and stable layers) sources, respectively. Seasonally, the three plant species absorbed more than 60% of their total water uptake from the moist layer and groundwater in the early(June) dry season;then, they switched to the active and stable layers in the rainy season(July–September) for water resources(50.1%–62.5%). In the late(October–November) dry season, P. sylvestris(54.5%–66.2%) and A. pedunculata(52.9%–63.6%) mainly used water from stable and moist layers, whereas S. psammophila(52.6%–70.7%) still extracted water predominantly from active and stable layers. Variations in the soil water profile induced by seasonal fluctuations in precipitation and groundwater levels and discrepancies in plant pheno

关键词： desert ecosystem MixSIAR model plant water uptake soil moisture stable isotopes vegetation restoration water-use efficiency

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