检索结果-南通市图书馆

journal of Materials Science & Technology 2022年第5期100卷 246-253页

作者： J.F.Zhao H.P.Wang B.Wei School of Physical Science and Technology Northwestern Polytechnical UniversityXi’an 710072China

A new intermetallic compound of thermodynamically stable Nb_(2)Ni phase is discovered within Nb-Ni binary system,refreshing the current situation that there are only three stable intermediate phases of Nb_(7)Ni_(6),NbNi_(3) and NbNi_(8).The new stable phase is generated from the peritectoid transition:(Nb)+Nb_(7)Ni_(6)→Nb_(2)Ni,and the transformation temperature is 1533 K.This refreshes the current equilibrium Nb-Ni binary phase diagram.It is confirmed by transmission electron microscopy and the annealing experiments,which is determined to be the fCC structure(Pearson:cf96,space grope:fd-3m O2,a=11.888A).furthermore,the equilibrium properties of Nb_(2)Ni phase are produced by density functional theory,including the formation energy,cohesive energy,bulk modulus and lattice constant.

关键词： Intermetallic compound Peritectoid transition Transmission electron microscopy Density functional theory Nb alloy

Battery prognostics and health management for electric vehicles under industry 4.0

在线全文

学校读者我要写书评

暂无评论

能源化学:英文版 2023年第9期84卷 30-33页

作者： jingyuan zhao Andrew f.Burke Institute of Transportation Studies University of California DavisDavisCA 95616USA

Transportation electrification is essential for decarbonizing transport. Currently, lithium-ion batteries are the primary power source for electric vehicles (EVs). However, there is still a significant journey ahead before EVs can establish themselves as the dominant force in the global automotive market. Concerns such as range anxiety, battery aging, and safety issues remain significant challenges.

关键词： Lithium-ion battery Prognostics and health management Machine learning Cloud Artificial intelligence Digital twins Lifelong learning

Review on supercapacitors:Technologies and performance evaluation

在线全文

学校读者我要写书评

暂无评论

journal of Energy Chemistry 2021年第8期30卷 276-291,I0006页

作者： jingyuan zhao Andrew f.Burke Institute of Transportation Studies University of California-Davis95616 DavisUSA Computer Science and Technology Shenzhen Institutes of Advanced TechnologyChinese Academy of Sciences518118 ShenzhenChina

The development of electrochemical capacitors(i.***.supercapacitors)have attracted a lot of attention in recent years because of the increasing demand for efficient,high-power energy storage.Electrochemical capacitors(ECs)are particularly attractive for transportation and renewable energy generation applications,taking advantage of their superior power capability and outstanding cycle life.Over the past decade,various advanced electrode materials and cell design are being studied to improve the energy density of ECs.Hybrid Li-ion capacitors and pseudo-capacitors that utilize fast surface redox reactions of metal oxide and doped polymers are the prime candidates being considered.This paper is concerned with the metrics being used to describe the performance of ECs and how the metrics are evaluated by testing devices and how the data from the testing are best interpreted.Emphasize is on relating testing of advanced ECs using materials more complex than activated carbons to testing electric double-layer capacitors(EDLCs)using carbon in both electrodes.A second focus of the paper is projecting the potential of the advanced materials and ionic liquid electrolytes for the development of complete EC cells having an energy density more than a factor of ten greater the energy density of the EDLC devices currently on the market.This potential was evaluated by calculating the performance(energy and power)of a series of ECs that utilize the advanced materials that have been studied by electrochemists over the past 10-15 years.The capacitance and resistance of the advanced ECs were calculated utilizing specific capacitance(f/g or f/cm^(3))and porosity data for the electrode materials and ionic conductivity of the electrolytes.It was concluded that hybrid ECs can be developed with energy densities of at least 50 Wh/kg,70 Wh/L with efficient power greater than 3 k W/kg.Continued research on micro-porous carbons with specific capacitance of 200 f/g and greater is needed.to achieve these EC performance goals.

关键词： Electrochemical capacitors Metrics Evaluation Cell design Applications

Large eddy simulations of a turbulent mixing layer periodically excited with fundamental and third harmonic frequency

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Aeronautics 2023年第5期36卷 33-40页

作者： jörg SCHLÜTER Dan zhao Abhishek SARKAR School of Engineering Deakin UniversityWaurn Ponds 3216Australia College of Engineering University of CanterburyChristchurch 8041New Zealand School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore

A better understanding of the mixing behavior of excited turbulent mixing layers is critical to a number of aerospace applications.Previous studies of excited turbulent mixing layers focused on single frequency excitation or the excitation with fundamental and its second harmonic frequency.There is a lack of detailed studies on applying low and higher frequency excitation.In this study,we have performed large-eddy simulations of periodically excited turbulent mixing layers.The excitation consists of a fundamental frequency and its third harmonic.We have used phase-averaging to identify the vortex structure and strength in the mixing layer,and we have studied the vortex dynamics.Two different vortex paring mechanisms are observed depending on the phase shift between the two excitation frequencies.The influence of these two mechanisms on the mixing of a passive scalar is also studied.It is found that exciting the mixing layer with these low and high frequencies has initially an adverse influence on the mixing process;however,it improves the mixing further downstream of the splitter plate with the excitation using a phase shift ofΔφ=πshowing the best mixing performance.The present works shed lights on the fundamental vortex dynamics,and has great potential for aeronautical,automotive and combustion engineering applications.

关键词： flow control flow excitation Large eddy simulations Turbulent mixing layer Vortex dynamics

Vibration Control of an Experimental flexible Manipulator Against Input Saturation

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA journal of Automatica Sinica 2023年第5期10卷 1340-1342页

作者： Zhijia zhao Sentao Cai Ge Ma f.Richard Yu the School of Mechanical and Electrical Engineering Guangzhou UniversityGuangzhou 510006 the Guangdong Laboratory of Artificial Intelligence and Digital Economy(SZ) Shenzhen 518060China the Guangdong Laboratory of Artificial Intelligence and Digital Economy(SZ) College of Computer Science&Software EngineeringShenzhen UniversityShenzhen 518060China

Dear Editor, This letter considers the control problem of an experimental flexible manipulator in position tracking, vibration suppression, and saturation compensation. Based on the backstepping technology and a Nussbaum function, we develop an anti-windup control to restrain the manipulator’s vibration, realize the desire trajectory tracking, and eliminate the saturation.

关键词： restrain eliminate Vibration

He-enhanced heterogeneity of radiation-induced segregation in feNiCoCr high-entropy alloy

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2022年第6期101卷 226-233页

作者： W.T.Lin G.M.Yeli G.Wang j.H.Lin S.j.zhao D.Chen S.f.Liu f.L.Meng Y.R.Li f.He Y.Lu j.j.Kai Department of Mechanical Engineering City University of Hong KongHong KongChina Institute of Nuclear&New Energy Technology Tsinghua UniversityBeijingChina Department of Physics Southern University of Science and TechnologyShenzhenChina Centre for Advanced Nuclear Safety and Sustainable Development City University of Hong KongHong KongChina School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhenChina School of Materials Science and Engineering Shanghai UniversityShanghaiChina Nano-Manufacturing Laboratory(NML) City University of Hong Kong Shenzhen Research InstituteShenzhenChina

Radiation-induced segregation(RIS) is a typical non-equilibrium process that can dramatically alter the behavior of defect sinks and material properties under irradiation. However, RIS mechanisms have been rarely studied around small He bubbles owing to the technical challenges involved in direct measurements of local chemistry. Here, using state-of-the-art atom probe tomography, we report the RIS behavior near He bubbles in the fe Ni Co Cr high-entropy alloy that indicates Co segregates most strongly, followed by weaker Ni segregation, whereas fe and Cr are depleted almost to the same degree. Exceptionally, the magnitude of Co segregation around He bubbles is higher than previously measured values at voids and dislocation loops. Electron energy-loss spectroscopy was used to measure the He density and pressure inside individual bubbles. We demonstrate that He bubbles are over-pressurized at the irradiation temperature that could result in the vacancy bias and the subsequent vacancy-dominated RIS mechanism.first-principles calculations further reveal that there are repulsive interactions between He and Co atoms that may reduce the frequency of Co-vacancy exchange. As a result, He atoms likely retard Co diffusion via the vacancy mechanism and enhance the heterogeneity of RIS in Co-containing multicomponent alloys. These insights could provide the basis for understanding He effects in nuclear materials and open an avenue for tailoring the local chemical order of medium-and high-entropy alloys.

关键词： High-entropy alloy Radiation-induced segregation He bubbles Atom probe tomography Electron energy-loss spectroscopy

Human T-cell immunity against the emerging and re-emerging viruses

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2017年第12期60卷 1307-1316页

作者： Min zhao Hangjie Zhang Kefang Liu George f.Gao William j.Liu Research Network of lmmunity and Health(RN1H) Beijing Institutes of Life ScienceChinese Academy of SciencesBeijing 100101China Key Laboratory of Medical Virology and Viral Diseases Ministry of Health of People's Republic of ChinaNational Institute for Viral Disease Control and PreventionChinese Center for Disease Control and PreventionBeijing 102206China CAS Key Laboratory of Pathogenic Microbiology and Immunology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China

Over the past decade, we have seen an alarming number of high-profile outbreaks of newly emerging and re-emerging viruses.Recent outbreaks of avian influenza viruses, Middle East respiratory syndrome coronaviruses, Zika virus and Ebola virus present great threats to global health. Considering the pivotal role of host T-cell immunity in the alleviation of symptoms and the clearance of viruses in patients, there are three issues to be primarily concerned about T-cell immunity when a new virus emerges: first, does the population possess pre-existing T-cells against the new virus through previous infections of genetically relevant viruses; second, does a proper immune response arise in the patients to provide protection through an immunopathogenic effect; lastly, how long can the virus-specific immune memory persist. Herein, we summarize the current updates on the characteristics of human T-cell immunological responses against recently emerged or re-emerged viruses, and emphasize the necessity for timely investigation on the T-cell features of these viral diseases, which may provide beneficial recommendations for clinical diagnosis and vaccine development.

关键词： emerging viruses avian influenza H7N9 MERS-CoV Zika Ebola human immunity T-cell cross-reactivity

Oryzalexin S biosynthesis:a cross-stitched disappearing pathway

在线全文

学校读者我要写书评

暂无评论

aBIOTECH 2023年第1期4卷 1-7页

作者： Le zhao Richard Oyagbenro Yiling feng Meimei Xu Reuben j.Peters Roy j.Carver Department of Biochemistry Biophysics and Molecular BiologyIowa State UniversityAmesIA50011USA

Rice produces many diterpenoid phytoalexins and,reflecting the importance of these natural products in this important cereal crop plant,its genome contains three biosynthetic gene clusters(BGCs)for such metabolism.The chromosome 4 BGC(c4BGC)is largely associated with momilactone production,in part due to the presence of the initiating syn-copalyl diphosphate(CPP)synthase gene(OsCPS4).Oryzalexin S is also derived from syn-CPP.However,the relevant subsequently acting syn-stemarene synthase gene(OsKSL8)is not located in the c4BGC.Production of oryzalexin S further requires hydroxylation at carbons 2 and 19(C2 and C19),presumably catalyzed by cytochrome P450(CYP)monooxygenases.Here it is reported the closely related CYP99A2 and CYP99A3,whose genes are also found in the c4BGC catalyze the necessary C19-hydroxylation,while the closely related CYP71Z21 and CYP71Z22,whose genes are found in the recently reported chromosome 7 BGC(c7BGC),catalyze subsequent hydroxylation at C2α.Thus,oryzalexin S biosynthesis utilizes two distinct BGCs,in a pathway cross-stitched together by OsKSL8.Notably,in contrast to the widely conserved c4BGC,the c7BGC is subspecies(ssp.)specific,being prevalent in ssp.japonica and only rarely found in the other major ssp.indica.Moreover,while the closely related syn-stemodene synthase OsKSL11 was originally considered to be distinct from OsKSL8,it has now been reported to be a ssp.indica derived allele at the same genetic loci.Intriguingly,more detailed analysis indicates that OsKSL8(j)is being replaced by OsKSL11(OsKSL8i),suggesting introgression from ssp.indica to(sub)tropical japonica,with concurrent disappearance of oryzalexin S production.

关键词： Biosynthetic gene clusters Phytoalexins Diterpenoids Rice evolution

Enhanced helium ion irradiation tolerance in a fe-Co-Ni-Cr-Al-Ti high-entropy alloy with L12 nanoparticles

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2023年第12期143卷 169-177页

作者： Y.L.zhao f.L.Meng T.Yang j.H.Luan S.f.Liu G.M.Yeli W.T.Lin W.H.Liu X.j.Liu C.T.Liu j.j.Kai School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China School of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Materials Science and Engineering Mechanical Behavior Division of Shenyang National Laboratory for Materials ScienceCity University of Hong KongHong KongChina Department of Mechanical Engineering City University of Hong KongHong KongChina Institute of Nuclear&New Energy Technology Tsinghua UniversityBeijing 100084China

L12-strengthened high entropy alloys(HEAs)with excellent room and high-temperature mechanical prop-erties have been proposed as promising candidates as structural materials for advanced nuclear systems.However,knowledge about their radiation response is fairly limited.In the present work,a novel HEA with a high density of L12 nanoparticles was irradiated with He ion at 500°C.Transmission electron microscope(TEM)and atom probe tomography(APT)were employed to study the evolution of mi-crostructural stability and radiation-induced segregation.Similar to the single-phase feCoNiCr HEA,the main microstructural features were numerous large faulted dislocation loops and helium bubbles.While the irradiation resistance of the present L12-strengthened HEA is much improved in terms of reduced bubble size,which could be attributed to the considerable He trapping efficiency of the coherent pre-cipitate/matrix interface and the enhanced capability of the interface for damage elimination when the matrix channel width is narrow.APT analysis revealed that an inverse-Kirkendall-mechanism-dominated radiation-induced segregation(RIS)occurs around bubbles,where a significant Co enrichment and Ni de-pletion can be clearly observed.In addition,the competing dynamics of ballistic mixing and elemental clustering that raised from the irradiation-enhanced diffusion in a highly supersaturated matrix,along with the low precipitation nucleation barrier due to the small lattice misfit,lead to a dynamical pre-cipitation dissolution and re-precipitation appears under irradiation.Such a promising phenomenon is expected to promote a potential self-healing effect and could in turn provide a sustainable irradiation tolerance over the operational lifetime of a reactor.

关键词： L12 nanoparticles High-entropy alloy Helium bubble Phase stability Radiation-induced segregation

Analysis of COVID-19 clusters involving vertical transmission in residential buildings in Hong Kong region

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Building Simulation 2023年第5期16卷 701-711页

作者： Pengcheng zhao Department of Mechanical Engineering The University of Hong KongPokfulamHong KongChina

Multiple clusters of coronavirus disease 2019(COVID-19)in Hong Kong have involved vertical transmissions in residential buildings,wherein the flats of confirmed cases were often vertically aligned.Data on the buildings and cases associated with 19 such clusters were retrieved and compared with the corresponding data on the entirety of Hong Kong region.Vertical transmissions usually occurred in old high-rise buildings with small flat areas and low estate prices during winter.In addition,infection occurred frequently among the elderly and among upstairs neighbours of index cases.Virus-laden aerosols may have been transmitted between flats mostly via shared drainpipes,and the vertical distribution of the confirmed cases in a building varied by its drainage system design.for buildings with their entire drainpipes installed indoors,both the upstairs and downstairs neighbours of the index case flats could be infected.By comparison,buildings with their drainage stacks installed outdoors had lower infection risks and demonstrated a clearer pattern of vertical transmission:most infected cases resided upstairs from the index case flats,indicating that the virus spread could be dominated by the stack effect.This study provides valuable data and analysis for developing epidemic control strategies for residential buildings.

关键词： drainage system high-rise building infection SARS-CoV-2 stack effect ventilation