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Evaluation of tensile properties of a compositemetal joint with a novel metal insert design by experimental and numerical methods

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Chinese Journal of Aeronautics 2017年第3期30卷 1004-1011页

作者： Xiaoquan CHENG Xiaoqi LI Jie zhang Qian zhang Yujia CHENG Benyin ZENG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China A VIC China Helicopter Research and Development Institute Jingdezhen 333001China

Composite-metal joints with a metal insert are one kind of connecting *** this paper,tensile experimental tests were carried out to investigate tensile properties of a compositemetal joint with a novel metal insert *** element models of the joint were established,and strain distribution and tensile strength were *** numerical results are in good agreement with the experimental *** show that the joint failure is dominated by shear properties of the resin *** the resin layer thickness in a certain range will improve the tensile strength of the joint,while increasing the radius of the fillet on the ending side of the metal insert will decrease the joint *** the resin layer plasticity will improve the joint *** effect of the embedded depth of the metal insert can be ignored.

关键词： Composite structure Failure mode Joints Metal insert Tensile properties

Steric paper based ratio-type electrochemical biosensor with hollow-channel for sensitive detection of Zn2+

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Science Bulletin 2017年第16期62卷 1114-1121页

作者： Li Li Yan zhang Lina zhang Shenguang Ge Mei Yan Jinghua Yu School of Chemistry and Chemical Engineering University of JinanJinan 250022China Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials University of JinanJinan 250022China

The construction of flexible platform possessing the functions of immobilizing, separating, rinsing, and high-throughput analysis plays a significant role in biological and clinical research. Herein, hollow- channel technique was integrated with lab-on-paper for the simultaneous determination of two different concentrations of Zn2＋ based on the origami principle, in which microfiuidic channels were first patterned on a cellulose paper using commercial solid-state wax printer. Hollow-channels were created by laser cutting method as the role of both injecting ending and reaction tank. After screen printing three elec- trodes system, the resulting planar paper sheets were then folded into steric structures and functional- ized by in-situ synthesized reduced graphene oxide. As a proof-of-concept, such lab-on-paper device was employed in the ratiometric electrochemical monitoring of zinc ion from the environment and HepG2 cells extract, by combining with co-catalysis of porous metal-organic frameworks and hemin/ G-quadruplex toward H202 in the linear range of 0.1-7,000 nmol/L. The results indicated that integrating hollow-channel with steric lab-on-paper offered a new methodological approach for the development of metal ions monitoring research. It is believed that it could be useful for various point-of-care related research fields, such as, on-site environmental monitoring, food safety, and disease diagnosis.

关键词： Flexible platform Lab-on-paper device Ratiometric electrochemical monitoring Zinc ion

High-resolution, full-color quantum dot light-emitting diode display fabricated via photolithography approach

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Nano Research 2020年第9期13卷 2485-2491页

作者： Wenhai Mei Zhenqi zhang Aidi zhang Dong Li Xiaoyuan zhang Haowei Wang Zhuo Chen Yanzhao Li Xinguo Li Xiaoguang Xu BOE Technology Group Co. Ltd.Beijing 100176China School of Software&Microelectronics Department Peking UniversityBeijing 102600China

Displays play an extremely important role in modern information society,which creates a never-ending demand for the new and better products and *** latest requirements for novel display technologies focus on high resolution and high color *** emerging technologies that include organic light-emitting diode(OL ED),micro light-emiting diode(micro-LED),quantum dot light-emitting diode(QLED),laser display,holographic display and others,QLED is promising owing to its intrinsic high color gamut and the possibility to achieve high resolution with photolithography ***,previously demonstrated photolthography techniques suffer from reduced device performance and color Impurities in subpixels from the *** this study,we demonstrated a sacrificial layer assisted patterming(SLAP)approach,which can be applied in conjunction with photolithography to fabricate high-resolution,full-colo quantum dot(QD)*** this approach,the negative photoresist(PR)and sacrificial layer(SL)were uilized to determine the pixels for QD deposition,while at the same time the SL helps protect the QD layer and keep it intact(named PR-SL approach).To prove this method's viability for QLED display manufacture,a 500-ppi,full-color passive matrix(PM)-QLED prototype was fabricated via this *** show that there were no color impurities in the subpixels,and the PM-QL ED has a high color gamut of 114%National Television Standards Committee(NTSC).To the best of our knowledge,this is the first ull-olor QLED prototype with such a high *** anticipate that this innovative patteming technique will open a new horizon for future display technologies and may lead to a disruptive and innovative change in display industry.

关键词： quantum dots sacrificial layer assisted patterning quantum dot light-emitting diodes photolithography high-resolution

Comparative kinetics of coal and oil shale pyrolysis in a micro fluidized bed reaction analyzer

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Carbon Resources Conversion 2019年第3期2卷 217-224页

作者： Yuming zhang Mengxuan Zhao Rongxuan Linghu Chengxiu Wang Shu zhang State Key Laboratory of Heavy Oil Processing College of Mechanical and Transportation EngineeringChina University of Petroleum-BeijingBeijing 102249PR China College of Materials Science and Engineering Nanjing Forestry UniversityNanjing 210037JiangsuPR China

The characteristics and kinetics of coal and oil shale pyrolysis were comparatively studied by using a micro fluidized bed reaction analyzer(MFBRA).The isothermal differential model was first applied to calculate the kinetic parameters of activation energy and frequency factor according to the major gas components during *** results showed that the major gas components released from coal and oil shale under the isothermal condition had different initiating and ending time points,and the difference was more significant under the programmed heating *** shrinking core model allowed better fitting relevance for the coal pyrolysis,while the three-dimension model was more suitable for oil shale pyrolysis,indicating that the gases from the pyrolysis process of coal and oil shale might go through different reaction *** activation energy of oil shale pyrolysis was 36.96 kJ·mol^(−1),larger than the value of pyrolysis of the two coals,which was 21.16 and 32.17 kJ·mol^(−1),*** above results justified that the oil shale pyrolysis with high ash contents was somehow more difficult to take place in terms of higher activation energy and the MFBRA could be a useful tool to give some insight into the intrinsic kinetics and reaction mechanisms of coal and oil shale pyrolysis.

关键词： Micro fluidized bed reaction analyzer Coal Oil shale Pyrolysis Kinetics

Atomic-scale study on the precipitation behavior of an Al-Zn-Mg-Cu alloy during isochronal aging

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Journal of Materials Science & Technology 2022年第13期108卷 281-292页

作者： Xingpu zhang Xiaotong Deng Haofei Zhou Jiangwei Wang Center of Electron Microscopy and State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China Center for X-Mechanics Department of Engineering MechanicsZhejiang UniversityHangzhou 310027China Wenzhou Key Laboratory of Novel Optoelectronic and Nano Materials Institute of WenzhouZhejiang UniversityWenzhou 325006China

The precipitation behavior of a 7075 Al alloy during isochronal heat treatments at three different heating rates has been studied using differential scanning calorimetry,high-angle-annular-dark-field scanningtransmission-electron microscope and density functional theory *** the early stage of aging,GPI and GPII zones form sequentially and cause two characteristic DSC ***,the formation ofη_(1) precipitates takes place concurrently withη’.A novel type of metastable phaseη_(1)’is identified as the precursor ofη_(1),which can lower the lattice misfit betweenη_(1) and Al matrix along the direction of[1010]_(η_(1))//[001]_(Al).Accordingly,a pathway for the formation ofη_(1) viaη_(1)’is ***η’together withη_(1) andη_(1)’contribute to the third DSC *** the further increase of temperature,ηprecipitates become *** on the quantitative analyses,the influence of the heating rate and ending temperature on the cross section and number density of phases formed is discussed.

关键词： Al-Zn-Mg-Cu alloys Precipitation Isochronal ageing HAADF-STEM Density functional theory

A Karman-Vortex Generator for passive separation control in a conical diffuser

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Science China(Physics,Mechanics & Astronomy) 2012年第5期55卷 828-836页

作者： zhang YuFei CHEN HaiXin FU Song School of Aerospace Engineering Tsinghua UniversityBeijing 100084China

Flow separation in a conical diffuser with large divergence angle （29.14°） and large area ratio （3.533） is eliminated by a novel passive flow control device called Karman-Vortex Generator （KVG）. The effect of the KVG is verified and investigated by the URANS, DES and DDES methods based on the SST model. CFD results show that the performance coefficient of the diffuser can be doubled by the KVG, and the total pressure recovery coefficient can be improved by about 1.2%. DES and DDES re- suits show that the KVG can introduce a Karman-vortex street frequency in the diffuser. This frequency decays rapidly, and could not be detected in the ending plane of the expansion section, Different KVG configurations with different locations and dimensions are numerically simulated and compared. Some suggestions are provided.

关键词： conical diffuser Karman-Vortex Generator separation control DES

Moho Structure of the Southwest Sub-Basin, South China Sea, from a Multichannel Seismic Reflection Profile NH973-1

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Journal of Ocean University of China 2019年第5期18卷 1105-1114页

作者： zhang Jinchang CHEN Jie HUANG Yanming CAS Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Fourth Institute of Oceanography Ministry of Natural ResourcesBeihai 536007China South China Sea Institute of Planning and Environmental Research Ministry of Natural ResourcesGuangzhou 510310China Key Laboratory of Exploration Technologies for Oil and Gas Resources Ministry of EducationYangtze UniversityWuhan 430100China

Moho structure provides important clues for understanding crustal structure,isostatic state and magmatic flux from mantle to ***-basin Moho structure of the South China Sea(SCS)is important for understanding crustal evolution mechanisms of both continental break-up and seafloor spreading *** Sub-basin(SWSB)opened up the latest and has the closest continental margins,making it the best to study the across-basin *** seismic(MCS)reflection data of line NH973-1 that crosses SWSB in NW-SE direction were reprocessed in order to image Moho *** MCS data,Moho reflectors are observed in places,which were not revealed in prior *** Moho generally shows symmetric structure on both sides of the central rift valley(CRV)and with variations in crustal *** CRV,the Moho is 2 seconds depth in two-way travel time(TWTT)beneath the igneous basement,which corresponds to 7 km depth,indicating normal oceanic crustal accretion during the ending of seafloor *** to the continent-ocean boundary(COB),the Moho becomes shallow to 1 second depth in TWTT(3.5 km),implying strong crustal thinning towards the continent,probably because of poor magma supply at the beginning of seafloor *** south COB,the Moho depth under the crust almost reaches zero,which could be explained as a result of exhumed *** addition,two low-angle,deep-penetrating normal faults are observed at south *** faults cut across the Moho into the upper mantle,which may be attributed to lithospheric hyper-stretching at COB during continental break-up.

关键词： Moho structure multichannel seismic reflection crustal structure South China Sea oceanic basin continent-ocean boundary

Effect of Temperature and Ram Speed on Isothermal Extrusion for Large-size Tube with Piece-wing

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Journal of Materials Science & Technology 2005年第4期21卷 499-504页

作者： He YANG Jun zhang Yangmin HE Bingtao HAN College of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 China Xi'an Heavy Machinery Research Institute Xi'an 710032 China

Heat energy change during the extrusion of 7075 aluminium alloy large-size tube with piece-wing in a container was analyzed. Extrusion load vs ram displacement diagrams and exit temperature vs ram displacement diagrams at various speeds were obtained by 3D FEM simulation. Results show that the exit temperature becomes higher as the ram speed and displacement increase. For large-size tube with piece-wing, there is certainly a curve of ram speed decreasing with increasing ram displacement, which enables isothermal extrusion to be achieved. Therefore,an attempt was made to divide the working stroke into five different zones. Each of them has a preset speed that decreases from the ram displacement beginning to the ending. And then, new exit temperature vs ram displacement diagram was obtained by 3D FEM simulation for the five different speeds. It is shown that the variation of exit temperature is very small. Through the above research, a basic method for realizing isothermal extrusion of 7075 large-size tube with piece-wing was obtained, that is, the working stroke was divided into several different zones with a decreasing speed during extrusion, each zonest speed was real-time adjusted on the feedback signal of exit temperature by proportional hydraulic valve through closed-loop control. The engineering experiment verification was carried out on 100 MN aluminium extrusion press with oil-driven double action. The experimental results of the exit temperature agrees with the simulation ones. The achievements of this study may serve as a significant guide to the practice of the relevant processes, particularly for isothermal extrusion. The verified method has been used in the design and manufacture of 125 MN aluminium extrusion press with oil-driven double action.

关键词： Extrusion Large-size aluminium profile FEM Temperature Unequal plastic deformation

Trajectory of COVID-19 response and management strategy in China:scientific rationale driven strategy adjustments

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Frontiers of Medicine 2024年第1期18卷 19-30页

作者： Zeyu zhang Yue Yan Lina Zhao Yizhou Bian Ning Zhao You Wu Dahai Zhao Zongjiu zhang Institute for Hospital Management Tsinghua UniversityBeijing100084China School of Medicine Tsinghua UniversityBeijing100084China School of International and Public Affairs Shanghai Jiao Tong UniversityShanghai200030China Yale University-Shanghai Jiao Tong University Joint Center for Health Policy Shanghai Jiao Tong UniversityShanghai200030China

The pneumonia caused by novel coronavirus SARS-CoV-2 infection in early December 2019,which was later named coronavirus disease 2019(COVID-19)by the World Health Organization(WHO),rapidly spread across the *** has made extraordinary efforts to this unprecedented pandemic,put its response and control at a very high level of infectious disease management(Category B but with measures for Category A),given top priority to the people and their lives,and balanced the pandemic control and socio-economic *** more than three years’fighting against this disease,China downgraded the management of COVID-19 to Category B infectious disease on January 8,2023 and the WHO declared the end of public health emergency on May 5,***,the ending of pandemic does not mean that the disease is no longer a health *** against COVID-19 from China and the whole world should be learned to prepare well for the future public health *** article gives a systematic review of the trajectory of COVID-19 development in China,summarizes the critical policy arrangements and provides evidence for the adjustment during policy making process,so as to share experiences with international community and contribute to the global health for all humanity.

关键词： COVID-19 public health response and control strategy science-based policy making