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Characteristics of Welding Crack Defects and Failure Mode in Resistance Spot Welding of DP780 Steel

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Journal of Iron and Steel Research International 2016年第10期23卷 1104-1110页

作者： Xiao-pei WANG yong-qiang zhang Jian-bin JU Jian-qiang zhang Jian-wei YANG Shougang Research Institute of Technology Beijing 100043 China College of Science China University of Petroleum (Beijing) Beijing 102249 China

The mechanical properties of welded joints in resistance spot welding of DP780 steel were tested,and three different types of welding cracks in welded joints were investigated by optical microscopy,scanning electron microscopy and electron back-scattered ***,the failure mode of the welded joints in shear tensile test was *** is found the shear tensile strength of welded joints can be greatly improved by adding preheating current or tempering *** surface crack in welded joint is intergranular fracture,while the inner crack in welded joint is transgranular fracture,and the surface crack on the edge of the electrode imprint can be improved by adding preheating current or tempering *** traditional failure mode criterion advised by American Welding Society is no longer suitable for DP780 spot welds and the critical nugget size suggested by Pouranvari is overestimated.

关键词： resistance spot welding mechanical property crack defect failure mode DP780 steel

Development of a high-speed digital pulse signal acquisition and processing system based on MTCA for liquid scintillator neutron detector on EAST

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Nuclear Science and Techniques 2023年第10期34卷 60-72页

作者： yong-qiang zhang Li-Qun Hu Guo-qiang Zhong Hong-Rui Cao Jin-Long Zhao Li Yang qiang Li Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Institute of Energy Hefei Comprehensive National Science CenterHefei 230031China

In this experimental study, involving deuterium–deuterium fusion neutron emission spectroscopy measurement on the experimental advanced superconducting tokamak(EAST), a liquid scintillator detector(BC501 A) was employed. This decision was based on the detector's superior sensitivity, optimal time-response, and its exceptional n–γ discrimination capability. This detector emits fast pulse signals that are as narrow as 100 ns, with high count rates that can peak at several Mcps. However, conventional nuclear circuits faced challenges in performing pulse height analysis, n–γ pulse shape discrimination, and in recording the entire pulse waveform under such high count rate conditions. To address these challenges, a high-speed digital pulse signal acquisition and processing system was designed. The system was developed around a micro-telecommunications computing architecture. Within this structure, a signal acquisition and processing(SAQP) module communicated through PCI Express links, achieving a bandwidth of up to 1.6 GB/s. To accurately capture the detailed shape of the pulses, four channels of analog-to-digital converters were used, each with a 500-MSPS sampling rate and a 14-bit resolution, ensuring an accuracy that surpassed 11 bits. An n–γ discrimination algorithm, based on the two-gate integral method, was also developed. Implemented within field programmable gate arrays, this algorithm provided a real-time n–γ discrimination spectrum for pulse height analysis. The system underwent rigorous testing in a laboratory setting and during an EAST experiment. The results confirmed that the innovative SAQP system can satisfy the demanding requirements of high-parameter experiments, manage count rates of up to 2 Mcps, execute real-time n–γ discrimination algorithms, and record entire pulse waveforms without any data loss.

关键词： EAST NES High-speed MTCA n–γdiscrimination Entire pulse waveform

Development of a wide-range and fast-response digitizing pulse signal acquisition and processing system for neutron flux monitoring on EAST

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Nuclear Science and Techniques 2022年第3期33卷 126-136页

作者： Li Yang Hong-Rui Cao Jin-Long Zhao Zi-Han zhang qiang Li Guo-Bin Wu yong-qiang zhang Guo-qiang Zhong Li-Qun Hu Zi-Jun zhang Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Hefei University of Technology Hefei 230009China

The neutron count rate fluctuation reaches six orders of magnitude between the ohmic plasma scenario and high power of auxiliary heating on an experimental advanced superconducting tokamak(EAST).The measurement result of neutron flux monitoring(NFM)is a significant feedback parameter related to the acquisition of radiation protection-related information and rapid fluctuations in neutron emission induced by plasma magnetohydrodynamic ***,a wide range and high time resolution are required for the NFM system on *** satisfy these requirements,a digital pulse signal acquisition and processing system with a wide dynamic range and fast response time was *** present study was conducted using a field-programmable gate array(FPGA)and peripheral component interconnect extension for instrument express(PXIe)*** digital dual measurement modes,which are composed of the pulse-counting mode and AC coupled square integral's Campbelling mode,were designed to expand the measurement range of the signal acquisition and processing *** time resolution of the signal acquisition and processing system was improved from 10 to 1 ms owing to utilizing highspeed analog-to-digital converters(ADCs),a high-speed PXIe communication with a direct memory access(DMA)mode,and online data preprocessing technology of *** signal acquisition and processing system was tested experimentally in the EAST radiation *** test results showed that the time resolution of NFM was improved to 1 ms,and the dynamic range of the neutron counts rate was expanded to more than 10^(6) counts per *** Campbelling mode was calibrated using a multipoint average linear fitting method;subsequently,the fitting coefficient reached ***,the newly developed pulse signal acquisition and processing system ensures that the NFM system meets the requirements of high-parameter experiments conducted on EAST more effectively.

关键词： EAST Neutron flux monitoring High time resolution Wide range Pulse signal acquisition and processing system

Calibration and performance of the neutron detector onboard of the DAMPE mission

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Research in Astronomy and Astrophysics 2020年第9期20卷 335-342页

作者： yong-Yi Huang Tao Ma Chuan Yue Yan zhang Ming-Sheng Cai Jin Chang Tie-Kuang Dong yong-qiang zhang Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210034China University of Chinese Academy of Sciences Beijing 100049China

The DArk Matter Particle Explorer(DAMPE),one of the four space-based scientific missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Sciences,was successfully launched on 2015 Dec.17 from Jiuquan launch *** of the most important scientific goals of DAMPE is to search for evidence of dark matter indirectly by measuring the spectrum of high energy cosmic-ray *** neutron detector,one of the four sub-payloads of DAMPE,is designed to distinguish high energy electrons from hadron background by measuring the secondary neutrons produced in the *** this paper,a comprehensive introduction of the neutron detector is presented,including the design,calibration and *** analysis with simulated data and flight data indicates a powerful proton rejection capability of the neutron detector,which plays an essential role for TeV electron identification of DAMPE.

关键词： neutron detector particle identification calibration simulation

Hydrothermal synthesis and characterization of nano-petal nickel hydroxide

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Rare Metals 2015年第9期34卷 667-672页

作者： Wen-Xiu He yong-qiang zhang Qian-Qing Liang Wen-Quan Jiang Hai-Feng Sun School of Chemistry Engineering Inner Mongolia University of Science and Technology Analysis & Measurements Research Center General Rearch Institute for Non-Ferrous Metals

The current article reports a preparation method of nano-petal nickel hydroxide, which was synthesized using urea as a precipitator by hydrothermal method. Nickel hydroxide samples with different microstructural characteristics were prepared by changing molar ratio of nickel/urea and reaction time. The prepared nickel hydroxide samples were characterized using X-ray diffraction(XRD) and scanning electron micrography(SEM).Electrochemical performances of the samples were then determined under charging–discharging rate of 0.2C. The influences of different conditions of the hydrothermal synthesis method on microstructure parameters of nickel hydroxide were analyzed, while relationships between microstructural characteristics parameters of nickel hydroxide and the electrochemical performances of nickel electrode were also explored.

关键词： Hydrothermal synthesis Nano-petal Electrochemical

Achieving room-temperature M_(2)-phase VO_(2) nanowires for superior thermal actuation

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Nano Research 2021年第11期14卷 4146-4153页

作者： yong-qiang zhang Kai Chen Hao Shen Yue-Cun Wang Mohamed Nejib Hedhili Xixiang zhang Ju Li Zhi-Wei Shan Center for Advancing Materials Performance from the Nanoscale State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an710049China Physical Science and Engineering Division King Abdullah University of Science and Technology(KAUST)Thuwal23955-6900Saudi Arabia Departments of Nuclear Science and Engineering and Materials Science and Engineering Massachusetts Institute of TechnologyCambridgeMA02139USA

Vanadium dioxide (VO_(2)) has emerged as a promising micro-actuator material for its large amplitude and high work density across the transition between the insulating (M_(1) and M_(2)) and metallic (R) phase. Even though M_(2)–R transition offers about 70% higher transformation stress than M_(1)–R structural phase transition, the application of the M_(2) phase in the micro-actuators is hindered by the fact that previously, M_(2) phase can only stay stable under tensile stress. In this work, we propose and verify that by synthesizing the VO_(2) nanowires under optimized oxygen-rich conditions, stoichiometry change can be introduced into the nanowires (NWs) which in turn yield a large number free-standing single-crystalline M_(2)-phase NWs stable at room temperature. In addition, we demonstrate that the output stress of the M_(2)-phase NWs is about 65% higher than that of the M_(1)-phase NWs during their transition to R phase, quite close to the theoretical prediction. Our findings open new avenues towards enhancing the performance of VO_(2)-based actuators by using M_(2)–R transition.

关键词： single crystalline vanadium dioxide(VO_(2))nanowires metal-insulator transition room-temperature M_(2)phase micro-actuator martensitic transformation transformation strain

Design of an energetic particle radiation diagnostic spectroscopy system based on national core chips and Qt on Linux in EAST

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Nuclear Science and Techniques 2021年第7期32卷 11-21页

作者： Ying-Ying Zheng Zi-Han zhang qiang Li Hong-Rui Cao yong-qiang zhang Jin-Long Zhao Qi-Ping Yuan Bing-Jia Xiao Ling-Ling Yan Jian-Qiu Zhu Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Hefei University of Technology Hefei 230009China

Energetic particle radiation diagnoses mainly detect the particles(such as neutrons,gamma rays,hard X-rays,and escaping electrons)that are radiated in the discharge process of the experimental advanced superconducting tokamak device to characterize the operating state of the plasma in real *** upgrading of these diagnoses requires new instruments based on national(here,“national”means developed and produced by a Chinese company)core chips and open-source software with advanced digitization,a high sampling rate,and a high time *** new spectroscopy system designed in this study adopts the national field-programmable gate array(FPGA)and an analog-to-digital converter as the core chip,and it is developed using Qt on *** communication between the FPGA and embedded controller occurs via a high-speed peripheral component interconnect eXtension for instrument express protocol with a direct memory access *** this basis,the time resolution of the system is improved from 2 to 1 ms,the maximum channel address is increased to 4096,and the sampling rate is increased from 10 to 80 *** experiments of the spectroscopy system with 152Eu and 137Cs sources demonstrate that the best energy resolution is 0.27%and the measurement error is less than±0.5 keV.

关键词： Spectroscopy system National chip Qt Energetic particle radiation Experimental advanced superconducting tokamak

Design of a high-dynamic-range prototype readout system for VLAST calorimeter

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Nuclear Science and Techniques 2023年第10期34卷 47-59页

作者： qiang Wan Jian-Hua Guo Xing Xu Shen Wang yong-qiang zhang Yi-Ming Hu Yan zhang Xu Pan Xiang Li Chuan Yue Wei Jiang Yu-Xin Cui Deng-Yi Chen Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China

In the future, the Very Large Area gamma-ray Space Telescope is expected to observe high-energy electrons and gamma rays in the MeV to TeV range with unprecedented acceptance. As part of the detector suite, a high-energy imaging calorimeter(HEIC) is currently being developed as a homogeneous calorimeter that utilizes long bismuth germanate(BGO) scintillation crystals as both absorbers and detectors. To accurately measure the energy deposition in the BGO bar of HEIC, a highdynamic-range readout method using a silicon photomultiplier(SiPM) and multiphotodiode(PD) with different active areas has been proposed. A prototype readout system that adopts multichannel charge measurement ASICs was also developed to read out the combined system of SiPMs and PDs. Preliminary tests confirmed the feasibility of the readout scheme, which is expected to have a dynamic range close to 10~6.

关键词： VLAST Calorimeter Readout system Front-end electronics Large dynamic range

Exploring Trade-offs in Thermal Interface Materials:The Impact of Polymer-Filler Interfaces on Thermal Conductivity and Thixotropy

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Chinese Journal of Polymer Science 2024年第7期42卷 916-925,I0006页

作者： Bin zhang Zheng-Li Dou yong-Zheng zhang qiang Fu Kai Wu College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu610065China

Effective thermal transport across solid-solid interfaces which is essential in thermal interface materials(TIMs),necessitates both optimal thixotropy and high thermal *** role of filler surface modification,a fundamental aspect of TIM fabrication,in the influence of these properties is not fully *** study employs the use of a silane coupling agent(SCA)to modify alumina,integrating experimental approaches with molecular dynamics simulations,to elucidate the interface effects on thixotropy and thermal conductivity in polydimethylsiloxane(PDMS)-based *** findings reveal that the variations of SCAs modify both interface binding energy and transition layer *** interface binding energy restricts macromolecular segmental relaxation near the interface,hindering desirable thixotropy and bond line *** the contrary,the thickness of the transition layer at the interface positively influences thermal conductivity,facilitating the transport of phonons between the polymer and ***,selecting an optimal SCA allows a balance between traditionally conflicting goals of high thermal conductivity and minimal bond line thickness,achieving an impressively low interface thermal resistance of just 2.45-4.29 K·mm^(2)·W^(-1)at275.8 kPa.

关键词： Thermal interface material Surface modification Thermal conductivity Thixotropy Interface thermal resistance