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Progress in Natural Science:Materials International 2024年第3期34卷 591-597页

作者： Dongmei zhang Yufan Li Yuchao Li Zhonggui Sun Hanxue Zhu Lujia Yang Yanhu zhan Yankai Li Shi Wang jun-wei zha School of Mathematical Sciences Liaocheng University School of Materials Science and Engineering Liaocheng University State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM) Nanjing University of Posts & Telecommunications School of Chemistry and Biological Engineering University of Science and Technology Beijing

A tri-layered(B-G-B) dielectric films were simply prepared by alternatively spin-coating boron nitride/polymethylmethacrylate(BN/PMMA, B) and graphene nanosheets(GNS/PMMA, G) compound solutions. The structure, morphology, thermal conductivity, and particularly the dielectric and relaxation behaviors were systematically studied. Results showed that a good exfoliation and dispersion of BN and GNS can be simply achieved through intensive mechanical compounding with PMMA in the internal mixer. The dielectric constant and breakdown strength of the obtained 1-3-1(B-G-B) sandwich composite film reached 4.3(@1 kHz) and 458.6kV/mm, being 119 % and 113 % higher than that of pure PMMA, respectively. Furthermore, the overall thermal conductivity of sandwich 1-3-1 composite increased by 112 % due to the addition of thermally conductive BN and GNS. The sandwich design strategy provided an effective way of achieving good permittivity, high insulation, and improved thermal conductivity simultaneously, showing potential applications in the miniaturization and integration of electronic devices.

关键词： Breakdown strength Composites Dielectric constant Sandwich structure Thermal conductivity

Theoretical analysis and application of polymer-matrix field grading materials in HVDC cable terminals

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High Voltage 2017年第1期2卷 39-46页

作者： Peng Han jun-wei zha Si-Jiao Wang Zhi-Min Dang Department of Polymer Science and Engineering University of Science and Technology BeijingBeijing 100083People’s Republic of China State Key Laboratory of Power System and Department of Electrical Engineering Tsinghua UniversityBeijing 100084People’s Republic of China

The distortion and uneven distribution of electric field in high-voltage direct current(HVDC)terminal insulator is the key problem for stable running of the power transmission *** flexible materials filled polymer-matrix composites with non-linear conductivity have also been considered to modify the distribution of electric field in cable *** factors having influence on the non-linear conductivity will be analysed in this review.

关键词： field conductivity matrix

Recyclability and Self-Healing of Dynamic Cross-Linked Polyimide with Mechanical/Electrical Damage

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Energy & Environmental Materials 2023年第1期6卷 401-407页

作者： Baoquan Wan Ming-Sheng Zheng Xing Yang Xiaodi Dong Yuchao Li Yiu-Wing Mai George Chen jun-wei zha School of Chemistry and Biological Engineering University of Science and Technology BeijingBeijing 100083China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology Beijing 100083China Shunde Graduate School of University of Science and Technology Beijing Foshan 528300China School of Materials Science and Engineering Liaocheng UniversityLiaocheng 252059China Centre for Advanced Materials Technology(CAMT) School of AerospaceMechanical and Mechatronic EngineeringThe University of SydneySydney New South Wales 2006Australia Department of Electronics and Computer Science University of SouthamptonSouthampton SO171BJUK

Recyclability and self-healing are two most critical factors in developing sustainable polymers to deal with environmental pollution and resource *** this work,a dynamic cross-linked polyimide insulation film with full closed-loop recyclability is successfully prepared,which also possesses good self-healing ability after being mechanical/electrical damaged depending on the Schiff base dynamic covalent *** recycled and self-healed polyimide film still maintain its good tensile strength(r t)>60 MPa with Young’s modulus(E)>4 GPa,high thermal stability with glass transition temperature(T g)>220℃,and outstanding insulation property with breakdown strength(E 0)>358 kV mm^(-1),making it a very promising low energy consumption and high temperature resistant insulation *** strategy of using Schiff base dynamic covalent bonds for reversible repairing the structure of high T g polyimides promotes the wider application of such sustainable and recyclable material in the field of electrical power and micro-electronics.

关键词： electrical damage polyimide recyclability self-healing

Improvements of dielectric properties and energy storage performances in BaTiO_(3)/PVDF nanocomposites by employing a thermal treatment process

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Journal of Advanced Dielectrics 2018年第6期8卷 108-117页

作者： Yue-Mao Dang Ming-Sheng Zheng jun-wei zha Tsinghua University High School Beijing 100084 P.R.China School of Biological and Chemical Engineering University of Science and Technology Beijing Beijing 100083 P.R.China

The influence of thermal treatment on the dielectric properties and energy storage performances of a classical dielectric nanocomposite system(barium titanate/polyvinylidene fluoride PVDF)was discussed *** results demonstrated that the permittivity of thermal treated nanocomposites increased and dielectric loss decreased compared with the untreated *** addition,the energy density was also greatly improved due to the inclined residual *** example,the energy density of the treated nanocomposite with 50 vol.%nanofillers was 3.14 times higher than the untreated nanocomposite at 50 MV/***,the charge–discharge efficiency was also promoted from 6.36%to 56.89%.According to the viewpoint of microstructure,the improvement of the dielectric and energy storage properties would be ascribed to the suppression on void defects in the interphase of dielectric nanocomposite by employing the thermal treatment ***,thermal treatment turns out to be a simple and an effective method to improve the dielectric performances and energy storage properties in the dielectric nanocomposites.

关键词： Thermal treatment BaTiO_(3)/PVDF nanocomposites dielectric properties energy storage

Geometric Error Identification of Gantry-Type CNC Machine Tool Based on Multi-Station Synchronization Laser Tracers

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 150-162页

作者： jun zha Huijie zhang School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China Xi’an Jiaotong University Suzhou Academy Suzhou 215123China

Laser tracers are a three-dimensional coordinate measurement system that are widely used in industrial *** propose a geometric error identification method based on multi-station synchronization laser tracers to enable the rapid and high-precision measurement of geometric errors for gantry-type computer numerical control(CNC)machine *** method also improves on the existing measurement efficiency issues in the single-base station measurement method and multi-base station time-sharing measurement *** consider a three-axis gantry-type CNC machine tool,and the geometric error mathematical model is derived and established based on the combination of screw theory and a topological analysis of the machine kinematic *** four-station laser tracers position and measurement points are realized based on the multi-point positioning principle.A self-calibration algorithm is proposed for the coordinate calibration process of a laser tracer using the Levenberg-Marquardt nonlinear least squares method,and the geometric error is solved using Taylor’s first-order linearization *** experimental results show that the geometric error calculated based on this modeling method is comparable to the results from the Etalon laser *** a volume of 800 mm×1000 mm×350 mm,the maximum differences of the linear,angular,and spatial position errors were 2.0μm,2.7μrad,and 12.0μm,respectively,which verifies the accuracy of the proposed *** research proposes a modeling method for the precise measurement of errors in machine tools,and the applied nature of this study also makes it relevant both to researchers and those in the industrial sector.

关键词： Multi-point positioning Multi-station synchronization CNC machine tool Geometric error Error separation

Electrospun poly(ethylene oxide) nanofibrous composites with enhanced ionic conductivity as flexible solid polymer electrolytes

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High Voltage 2017年第1期2卷 25-31页

作者： jun-wei zha Na Huang Kang-Qiang He Zhi-Min Dang Chang-Yong Shi Robert KwokYiu Li Department of Physics and Materials Science City University of Hong KongTat Chee AvenueKowloonHong KongPeople’s Republic of China Department of Polymer Science and Engineering School of Chemistry and Biological EngineeringUniversity of Science and Technology BeijingBeijing 100083People’s Republic of China State Key Laboratory of Electrical System Department of Electrical EngineeringTsinghua UniversityBeijing 100084People’s Republic of China Department of Elements Beijing Institute of Fashion TechnologyBeijing 100029People’s Republic of China

Solid polymer electrolytes(SPEs)have great potential to address the safety issues of lithium(Li)-ion batteries when compared with conventional liquid electrolytes,which makes them a promising alternative for next-generation high-energy *** this work,poly(ethylene oxide)-lithium perchlorate(PEO–LiClO4)polymer electrolytes for Li-ion batteries were prepared using *** crystallinity,ionic conductivity as well as mechanical properties were *** conductivities and mechanical properties of PEO–LiClO4 based SPE have been obviously increased by incorporating modified TiO2 nanofibres(TNFs)than TiO2 nanoparticles(TNPs),due to that both TNFs and TNPs can decrease the crystalline phase concentration of PEO and increase segmental flexibility of *** SPE with 3 wt%TNFs exhibits the highest conductivity of 5.308×10−5 S cm−1 at 20°C and higher tensile strength of 13.8 *** results highlight the potential of utilising the electrospinning method to improve the ionic conductivity of SPEs.

关键词： conductivity ionic polymer

Enhanced thermal conductivity and dielectric properties in electrostatic self-assembly 3D pBN@nCNTs fillers loaded in epoxy resin composites

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Journal of Materiomics 2020年第4期6卷 751-759页

作者： Dong-Li zhang Sheng-Nan Liu Hui-Wu Cai Qi-Kun Feng Shao-Long Zhong jun-wei zha Zhi-Min Dang State key Laboratory of Power System Department of Electrical EngineeringTsinghua UniversityBeijing100084China School of Chemistry and Chemical Engineering Xi’an University of Science and TechnologyXi’an710054China School of Chemistry and Biological Engineering University of Science and Technology BeijingBeijing100083China Center on Frontier Technologies for Advanced Power Transmission and Distribution Equipment School of Electrical EngineeringZhengzhou UniversityHenan450001China

High-performance epoxy(EP)composites with excellent thermal conductivity and dielectric properties have attracted increasing attention for effective thermal *** this work,three-dimensional(3D)structural functional fillers were prepared by an electrostatic self-assembly *** negatively charged carbon nanotubes(nCNTs)prepared by carboxylation on the surface of CNTs were attached to the positively charged boron nitride(pBN)to form the 3D pBN@nCNTs functional *** morphological characterizations of the formed 3D pBN@nCNTs fillers and epoxy composites were established,illustrating that nCNTs were linearly overlapped between the BN sheets,thus forming a 3D heat conduction network in the epoxy *** synergistic effect of pBN with nCNTs on the enhancement of thermal conductivity and dielectric properties of composites was systematically *** experimental results demonstrated that the thermal conductivity of pBN@nCNTs/EP composites could reach 1.986 W m1K1 with the loading of 50 wt%fillers at 10:1 mass ratio of pBN:nCNTs,which is 464%and 124%higher than that of pure EP and BN/EP,***,the dielectric permittivity was successfully increased to ***,the thermal stability of the composites was synchronously *** study provides a facile path to fabricate thermosetting polymer composites with high thermal conductivity and dielectric properties.

关键词： Thermal conductivity Dielectric permittivity Composites Electrostatic self-assembly

Reinforcement Learning Navigation for Robots Based on Hippocampus Episode Cognition

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Journal of Bionic Engineering 2024年第1期21卷 288-302页

作者： Jinsheng Yuan wei Guo Zhiyuan Hou Fusheng zha Mantian Li Pengfei Wang Lining Sun State Key Laboratory of Robotics and System Harbin Institute of Technology(HIT)Harbin 150001China Shenzhen Academy of Aerospace Technology Shenzhen 518057China School of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050China

Artificial intelligence is currently achieving impressive success in all ***,autonomous navigation remains a major challenge for *** learning is used for target navigation to simulate the interaction between the brain and the environment at the behavioral level,but the Artificial Neural Network trained by reinforcement learning cannot match the autonomous mobility of humans and *** hippocampus–striatum circuits are considered as key circuits for target navigation planning and *** paper aims to construct a bionic navigation model of reinforcement learning corresponding to the nervous system to improve the autonomous navigation performance of the *** ventral striatum is considered to be the behavioral evaluation region,and the hippocampal–striatum circuit constitutes the position–reward *** this paper,a set of episode cognition and reinforcement learning system simulating the mechanism of hippocampus and ventral striatum is constructed,which is used to provide target guidance for the robot to perform autonomous *** with traditional methods,this system reflects the high efficiency of learning and better Environmental *** research is an exploration of the intersection and fusion of artificial intelligence and neuroscience,which is conducive to the development of artificial intelligence and the understanding of the nervous system.

关键词： Episode cognition Reinforcement learning Hippocampus Robot navigation

Risk factors for postpartum posttraumatic stress disorder after emergency admission

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World Journal of Emergency Medicine 2024年第2期15卷 121-125页

作者： Fengxia Du jun zha Yan Li Lichao Fang Shuyu Xia Youjia Yu Department of Obstetrics Suzhou Xiangcheng People’s HospitalSuzhou 215131China Department of Anesthesiology the Second Affiliated Hospital of Wannan Medical CollegeWuhu 241000China Department of Anesthesiology Suzhou Xiangcheng People’s HospitalSuzhou 215131China Department of Emergency and Intensive Care Unit Suzhou Xiangcheng People’s HospitalSuzhou 215131China

BACKGROUND:Postpartum posttraumatic stress disorder(PTSD)can occur in women who give birth after emergency *** identification of risk factors for this condition is crucial for developing effective preventive *** retrospective study aimed to explore the incidence and risk factors for postpartum PTSD in women who give birth after emergency ***:Medical records of women who gave birth after emergency admission were collected between March 2021 and April *** patients’general conditions and perinatal clinical indicators were *** puerperae were divided into PTSD group and control group based on symptom occurrence at six weeks *** logistic regression analysis was performed to identify risk ***:A total of 276 puerperae were included,with a PTSD incidence of 20.3% at six weeks *** logistic regression analysis identified emergency cesarean section(odds ratio[OR]=2.102;95%confidence interval[CI]:1.114-3.966,P=0.022),admission to the emergency department after midnight(12:00 AM)(OR=2.245;95%CI:1.170-4.305,P<0.001),and cervical dilation(OR=3.203;95%CI:1.670–6.141,P=0.039)as independent risk factors for postpartum *** pump use(OR=0.500;95%CI:0.259–0.966,P=0.015)was found to be a protective factor against postpartum ***:Emergency cesarean section,admission to the emergency department after midnight,and cervical dilation were identified as independent risk factors for postpartum PTSD,while analgesic pump use was a protective *** findings provide insights for developing more effective preventive measures for women who give birth after emergency admission.

关键词： Risk factors Posttraumatic stress disorder Emergency Delivery

Atomic tailoring-induced deficiency in tungsten oxides for high-performance energy-related devices

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Tungsten 2024年第2期6卷 269-277页

作者： Jing-Huang Lin Yao-Tian Yan jun-Lei Qi Chen-Yang zha Institute of Applied Physics and Materials Engineering Zhuhai UM Science and Technology Research InstituteUniversity of MacaoTaipaMacao SAR 999078China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Jiangmen Laboratory of Carbon Science and Technology Hong Kong University of Science and Technology(Guangzhou)Jiangmen 529199China Key Laboratory of Flexible Electronics School of Flexible Electronics(Future Technologies)Institute of Advanced MaterialsNanjing Tech UniversityNanjing 211816China

Nowadays,tungsten oxides,as a typical transition metal oxide,are widely and intensively investigated owing to their excellent material properties and device *** oxygen defi ciency in tungsten oxides is typically the key to enhance their performances for a variety of critical technological *** a gradual increase of oxygen defi ciency,various non-stoichiometric tungsten oxides can be formed by re-adjustment of the atomic arrangement,which exhibits superior performances than their traditional stoichiometric *** review mainly focuses on the recent advances in oxygen-defi cient tungsten oxides from the point of atomic structures,including the forming mechanism of non-stoichiometric tungsten oxides and the superiority of these oxygen-defi cient tungsten oxides in energy-related ***,the challenge and perspective of oxygen-defi cient tungsten oxides are also discussed.

关键词： Oxygen defi ciency Tungsten oxide Atomic structures Catalyst Storage