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Organic Chemistry Frontiers 2022年第6期9卷 1662-1667页

作者： Peng Qian linna Xu Wenyan Wang lin zhang Liang Tang Jiaojiao Liu Liangquan Sheng School of Chemistry and Material Engineering Engineering Research Center of Biomass Conversion and Pollution Prevention of Anhui Educational InstitutionsFuyang Normal UniversityFuyangAnhui236037P.R.China

An electrochemically oxidative domino cyclization reaction of methyl azaarenes/ketones with pyrazol-5-amines and 6-amino-pyrimidine-2,4-diones was developed, providing a variety of dipyrazolo[3,4-b:4’,3’-e]pyridines and dipyrimidine-fused pyridines with moderate to good yields. The reaction involved two C–C bond formations and one C–N bond formation in one pot. Moreover, the photoluminescence properties of the representative dipyrazolo[3,4-b:4’,3’-e]pyridines were investigated.

关键词： pyridine oxidative pyrimidine

Optimal Design of Flexible Job Shop Scheduling Under Resource Preemption Based on Deep Reinforcement Learning

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Complex System Modeling and Simulation 2022年第2期2卷 174-185页

作者： Zhen Chen lin zhang Xiaohan Wang Pengfei Gu School of Automation Science and Eletrical Engineering Beihang UniversityBeijing 100191China

With the popularization of multi-variety and small-batch production patterns,the flexible job shop scheduling problem(FJSSP)has been widely studied.The sharing of processing resources by multiple machines frequently occurs due to space constraints in a flexible shop,which results in resource preemption for processing workpieces.Resource preemption complicates the constraints of scheduling problems that are otherwise difficult to solve.In this paper,the flexible job shop scheduling problem under the process resource preemption scenario is modeled,and a two-layer rule scheduling algorithm based on deep reinforcement learning is proposed to achieve the goal of minimum scheduling time.The simulation experiments compare our scheduling algorithm with two traditional metaheuristic optimization algorithms among different processing resource distribution scenarios in static scheduling environment.The results suggest that the two-layer rule scheduling algorithm based on deep reinforcement learning is more effective than the meta-heuristic algorithm in the application of processing resource preemption scenarios.Ablation experiments,generalization,and dynamic experiments are performed to demonstrate the excellent performance of our method for FJSSP under resource preemption.

关键词： flexible job shop scheduling resource preemption deep reinforcement learning two-level scheduling

A study on predicting crisis information dissemination in epidemic-level public health events

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Journal of Safety Science and Resilience 2023年第3期4卷 253-261页

作者： lin zhang Xin Wang Jinyu Wang Ping Yang Peiling Zhou Ganli Liao School of Economics and Management Beijing Information Science and Technology UniversityBeijing 100192China Beijing Academy of Science and Technology Beijing 100089China

Crisis information dissemination plays a key role in the development of emergency responses to epidemic-level public health events.Therefore,clarifying the causes of crisis information dissemination and making accurate predictions to effectively control such situations have attracted extensive attention.Based on media richness theory and persuasion theory,this study constructs an index system of crisis information dissemination impact factors from two aspects:the crisis information publisher and the published crisis information content.A multi-layer perceptron is used to analyze the weight of the index system,and the prediction is transformed into a pattern classification problem to test crisis information dissemination.In this study,COVID-19 is considered a representative event.An experiment is conducted to predict the crisis information dissemination of COVID-19 in two megacities.Data related to COVID-19 from these two megacities are acquired from the well-known Chinese social media platform Weibo.The experimental results show that not only the identity but also the social influence of the information publisher has a significant impact on crisis information dissemination in epidemic-level public health events.Furthermore,the proposed model achieves more than 95%test accuracy,precision rate,recall value and f1-score in the prediction task.The study provides decision-making support for government departments and a guide for correctly disseminating crisis information and public opinion during future epidemic-level public health events.

关键词： Epidemic-level public health events COVID-19 Crisis information dissemination Machine learning Intelligent prediction

Multi-functional stainless steel composite frames stabilize the sodium metal battery

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Journal of Materials Science & Technology 2023年第18期149卷 112-118页

作者： Laiping Li Yusheng Luo Wenlu Yuan Peizhi Mou Qi Wu lin zhang Yong Chen Jie Shu Liyuan zhang School of Materials Science and Chemical Engineering Ningbo UniversityNingbo 315211China

The sodium(Na)metal battery has the prospect of promising high energy density and sustainable tech-nology for low-cost energy storage.However,the soft texture and high reactivity of Na cause it easy to structure collapse and produce side reactions with organic electrolytes.Inspired by ancient Chinese ar-chitecture,a structural engineering strategy is introduced to conquer the above issues.PVDF film-covered stainless steel mesh(SMPF)embedded in the obverse of Na metal to form a“self-limiting”Na/electrolyte interface and bare stainless steel mesh(SM)with high electronic conductivity embedded in the reverse of Na metal to form a uniformly electronic distributed Na/collector interface.Based on the electric field simulation and in-situ optical tests,the well-designed structure of the SM@Na@SMPF electrode can re-strict the dendrite growth and slow down the bubbles release.The above strategies provide important technical support for the large-scale application of flexible Na metal batteries.

关键词： Sodium metal battery Stainless steel mesh Self-limiting Electric field simulation Bubbles release

Mechanical property and thermal shock behavior of tungsten-yttria-stabilized zirconia cermet fabricated by spark plasma sintering

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Tungsten 2024年第1期6卷 134-140页

作者： lin-Chao zhang Ke Jing Rui Liu Zhuo-Ming Xie Jun-Feng Yang Gang Li Xian-Ping Wang Xue-Bang Wu Qian-Feng Fang Chang-Song Liu Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610041China

The cermet fuels have been considered as a potential key component for the nuclear thermal propulsion,and the homogeneity of the fuel particles in the metal matrix plays a crucial role in stabilizing the structure at extremely high temperatures.In this work,liquid paraffin was used as additive to improve the distribution of yttria-stabilized zirconia(YSZ,an appropriate surrogate for UO_(2) fuel)microspheres in the tungsten(W)matrix,and the W-YSZ cermet wafers(volume ratio 1:1)with a relative density of 97.6%were fabricated by spark plasma sintering with a specifically designed program.The effects of the paraffin dosage(0-5 wt.%)on the homogeneity,microstructure,mechanical properties,and the thermal conductivity of W-YSZ cermet were investigated.The W-YSZ sample with 2 wt.%paraffin shows the highest homogeneity and exhibits the best comprehensive properties,including the ultimate tensile strength of 132.2 MPa at 600℃,the bending strength of455 MPa and thermal conductivity of 50 W·m^(-1)·K^(-1)at room temperature.Moreover,the cermet could keep structurally sound after thermal shocked at a heat load of 20 MW·m^(-2).These results would be helpful for the design and optimization of the cermet fuels in the nuclear thermal propulsion.

关键词： Nuclear thermal propulsion Tungsten Cermet Liquid paraffin Thermal shock

From tree to forest:Multiple carbon sink constraints

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The Innovation 2023年第4期4卷 19-20页

作者： Hui Liu lin zhang Qin Ma Wei Zhao Yiping Chen Guangdong Provincial Key Laboratory of Applied Botany Key Laboratory of Vegetation Restoration and Management of Degraded EcosystemsSouth China Botanical GardenChinese Academy of SciencesGuangzhou 510650China South China National Botanical Garden Guangzhou 510650China State Key Laboratory of Tibetan Plateau Earth System Environmentand Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China School of Geography Nanjing Normal UniversityNanjing 210023China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China School of Geospatial Engineering and Science Sun Yat-Sen UniversityZhuhai 519082China

Forests are the largest carbon sinks among terrestrial ecosystems.They sequestrate carbon primarily through tree growth but are currently under severe threat from global change.Recently,Tavares et al.1 identified a crucial trait,the xylem hydraulic safety margin(HSM),for predicting the risk of drought-induced tree mortality and biomass in Amazon forests.They also found that old-growth forests with wide HSMs build more biomass,while fast-growing forests are exposed to greater hydraulic risks and have a higher mortality rate.

关键词： forest tree carbon

Application of Ag-Cu-Ti active metal composite filler in ceramic joining:a review

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Frontiers of Materials Science 2023年第4期17卷 1-35页

作者： Yuhang Li Jun WANG Ziyan SHEN Hangli Qian Wanliang zhang Kaiyu zhang Danqing Ying Qihang Zhou Chengshuang Zhou lin zhang Institute of Material Forming and Control Engineering Zhejiang University of TechnologyHangzhou 310014China Zhejiang Baima Lake Laboratory Co. Ltd.Hangzhou 310000China

As a structural and functional material with excellent properties,ceramics play an extremely important role in a wide range of industries,including life and production.To expand the range of applications for ceramic materials,ceramics are often joined to metals and then used.Among the physical and chemical joining methods of ceramics to metals,the AMB method is efficient and simple,suitable for industrial applications,and has been a hot topic of research.However,due to the problems of residual stresses caused by the large difference in thermal expansion coefficients between ceramic and metal brazing,composite fillers have become a very worthwhile solution by regulating the physical properties of the brazing material and improving the weld structure.This review describes the wetting principle and application of Ag‒Cu‒Ti active metal filler in the field of ceramic joining,with emphasis on the current stage of composite filler,and discusses the influence on the former brazing properties and organization after the introduction of dissimilar materials.

关键词： brazing composite filler residual stress active metal ceramic‒metal joints

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基于选区激光熔化镍基单晶高温合金的修复

中国有色金属学报 2024年第4期34卷 1376-1392页

作者：张宇沈超张鹏章林曲选辉北京科技大学新材料技术研究院北京100083 北京科技大学北京材料基因组高精尖创新中心北京100083 辽宁材料实验室材料智能技术研究所沈阳110000

选区激光熔化技术光斑和热影响区小,成形精度高,可对镍基单晶高温合金叶片进行有效的修复以延长使用寿命。本工作选用了一种具有中等体积分数γ′相的合金粉末,研究了在单晶CM247LC基板上进行外延生长过程中该合金粉末的显微组织演变规... 详细信息

选区激光熔化技术光斑和热影响区小,成形精度高,可对镍基单晶高温合金叶片进行有效的修复以延长使用寿命。本工作选用了一种具有中等体积分数γ′相的合金粉末,研究了在单晶CM247LC基板上进行外延生长过程中该合金粉末的显微组织演变规律以及力学性能。结果表明:修复界面的熔池宽深比大于4时,沉积区与基体能形成良好的结合界面以及较小的晶粒取向差。通过增大扫描速率和降低激光功率可以有效减小沉积区裂纹密度,沉积组织以沿沉积方向生长的柱状枝晶为主,沉积层越高,冷却速率越小,枝晶间距和晶粒取向差越大。通过打印参数优化,最终得到了裂纹密度低、晶粒取向单一、且与单晶基板结合优异的镍基单晶高温合金沉积层,其抗拉强度为1094 MPa,伸长率为21%。

关键词：镍基单晶高温合金选区激光熔化显微组织晶粒取向力学性能

Design and commissioning of a wideband RF system for CSNS-Ⅱ rapid-cycling synchrotron

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Nuclear Science and Techniques 2024年第1期35卷 35-44页

作者： Jian Wu Xiang Li Bin Wu Chun-lin zhang Yang Liu Wei Long Xiao Li University of Chinese Academy of Sciences Beijing 100049China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China

The China Spallation Neutron Source(CSNS) upgrade project(CSNS-Ⅱ) aims to enhance the beam power from 100 to 500 kW. A dual-harmonic accelerating method has been adopted to alleviate the stronger space-charge effect in rapid-cycling synchrotrons owing to the increased beam intensity. To satisfy the requirements of dual-harmonic acceleration, a new radiofrequency(RF) system based on a magnetic alloy-loaded cavity is proposed. This paper presents design considerations and experimental results regarding the performance evaluation of the proposed RF system through high-power tests and beam commissioning. The test results demonstrate that the RF system satisfies the desired specifications and affords significant benefits for CSNS-Ⅱ.

关键词： Dual-harmonic acceleration Magnetic alloy-loaded cavity RF system

Microstructure and Mechanical Properties of Friction Stir Welded 1.5GPa Martensitic High-Strength Steel Plates

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Acta Metallurgica Sinica(English Letters) 2022年第7期35卷 1079-1089页

作者： Pengcheng Zhu lin zhang Zhaochang Li KHLo Jianfeng Wang Yufeng Sun Shaokang Guan School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China BAIC Group Off-Road Vehicle Co.Ltd Beijing 101300China Department of Electromechanical Engineering Faculty of Science and TechnologyUniversity of MacaoMacaoChina Henan Key Laboratory of Advanced Magnesium Alloys Zhengzhou 450002China

In this study, 2.4 mm thick high-strength martensitic steel plates with a tensile strength of 1500 MPa were friction stir welded at various welding speeds of 40, 60, 80, 100, 120 mm/min and a constant rotation speed of 300 rpm. Sound joints could be obtained when the welding speed was 40, 60 and 80 mm/min, while a kissing bond was found in the joint welded at 100 and 120 mm/min. It was revealed that the peak temperature exceeded A C3(the end temperature at which all ferrite transformed to austenite when the steel was heated) for all the welding conditions and martensitic structures were fi nally formed in the stir zone of the joints. A signifi cant decrease in hardness was located in the heat-aff ected zone, which had a transitional microstructure from tempered martensite near base metal to a mixed structure containing hard martensite, soft ferrite and bainite near stir zone. For the sound joints, the specimen was fractured in the heat-aff ected zone during tensile tests and the highest tensile strength could reach about 1058 MPa.

关键词： Martensitic steel Friction stir welding Heat-aff ected zone Microstructure Mechanical properties