检索结果-南通市图书馆

Pressure Evolution of the Magnetism and Fermi Surface of ybPtBi Probed by a Tunnel Diode Oscillator Based Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2022年第9期39卷 41-46页

作者： y.E.Huang F.wu A.Wang y.Chen L.Jiao M.Smidman H.q.yuan Center for Correlated Matter and Department of Physics Zhejiang UniversityHangzhou 310058China Zhejiang Province Key Laboratory of quantum Technology and Device Department of PhysicsZhejiang UniversityHangzhou 310058China State Key Laboratory of Silicon Materials Zhejiang UniversityHangzhou 310058China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

A central research topic in condensed matter physics is the understanding of the evolution of various phases and phase transitions under different tuning parameters such as temperature, magnetic field and pressure. To explore the pressure-induced evolution of the magnetism and Fermi surface of the heavy fermion antiferromagnet yb Pt Bi, we performed tunnel diode oscillator based measurements under pressure at low temperatures in high magnetic fields. Our results reveal that the magnetic order strengthens and the Fermi surface shrinks as the pressure increases, which are consistent with typical observations for yb-based heavy fermion compounds. In addition, an anomalous change in the quantum oscillation amplitudes is observed above 1.5 GPa, and determining the origin requires further study.

关键词： Fermi Probe oscillation

DEVELOPMENT AND APPLICATION OF ADAPTIVE MESH TECHNIqUE IN THREE DIMENSIONAL NUMERICAL SIMULATION OF WELDING PROCESS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2000年第1期13卷 33-39页

作者： q. y.Shi A. L. Lu H. y.Zhao A.P. wu (Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China)

The adaptive mesh mesh technique is developed and applied in three dimensional numerical simulation of welding process on the base of the commercial software. Special user subroutine is worked out to accom- plish this *** technique can make the dense mesh moving simultaneously with the heat source while the other area of the structure with much coarser mesh, greatly reducing the number of nodes and elements in the *** field,displacement and stress distributions during welding pro- cess me analyzed by FEM method with adaptive mesh and the analysis is also conducted with normal FEM method. The temperature field,displacement and stress distributions obtained with both methods are shown in contrast. The results show that the temperature fields and the displacement distributions of simulation on adaptive mesh correspond wery well with that of without adaptive mesh. Though the stress distributions have some difference,but the trends of the stress distribution are *** com- parison of the computing time of the two meshes indicates that the adaptive that the adaptive mesh can greatly reduce the calculation time when used for welding process.

关键词： adaptive mesh numerical simulation,temperature distribution,welding stress,welding displacement

Experimental methods for determination of mechanical behaviors of materials at high temperatures via the split Hopkinson bars

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2020年第6期36卷 1275-1293,I0003页

作者： q.B.Dou K.R.wu T.Suo C.Zhang X.Guo y.Z.Guo W.G.Guo y.L.Li School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Joint International Research Laboratory of Impact Dynamics and its Engineering Application Xi’an710072China Shaanxi Key Laboratory of Impact Dynamics and its Engineering Application Xi’an710072China State Key Laboratory for Strength and Vibration of Mechanical Structures School of AerospaceXi’an Jiaotong UniversityXi’an710049China

Full understanding of the thermomechanical behaviors of materials at high strain rates and high temperatures are of great importance from not only scientific meaning but also practical value in engineering structure design and safety *** efforts have been made for abilities of operation the split Hopkinson bars,the most popular technique for experimental determination of mechanical behaviors of materials over the strain rates from 10^2 to 10^4 s^−1 over the past 70 years,at high temperatures since 1960s.A review of experiment work is presented in this paper to give an overview of the development of experimental techniques at high temperatures based on Hopkinson bar *** principles of the split Hopkinson bar requires the loading bars avoiding temperature gradient or keeping relatively low temperature when performing high temperature *** such as performing temperature gradient corrections,rapid heating or using special designed automatically assembled systems were proposed by researchers to enable the operation of the split Hopkinson bars at temperature as high as ***,to the application of high speed photographic technique for capturing the dynamic deformation process of the specimen in high temperature Hopkinson bar testing,some key issues of eliminating the strong thermal radiation induced lights oversaturation and de-blurring of images due to insufficient exposure at high temperature and high strain rate condition,as well as fabrication of high contrast speckle pattern for high temperature digital image correlation measurement were also *** technique can now enable the split Hopkinson bar testing to be performed at high temperature up to 1873 K under the loading conditions of compression or tension with the in situ observation and full field measurement of deformation as *** paper concludes with summaries of the most important achievements and highlighting of the prospects,trends and remaining challenge

关键词： Mechanical behaviors Split Hopkinson bar High strain rate High temperature

Detection of false data injection attacks on power systems using graph edge-conditioned convolutional networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Protection and Control of Modern Power Systems 2023年第2期8卷 1-12页

作者： Bairen Chen q.H.wu Mengshi Li Kaishun Xiahou School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

State estimation plays a vital role in the stable operation of modern power systems,but it is vulnerable to cyber *** data injection attacks(FDIA),one of the most common cyber attacks,can tamper with measure-ment data and bypass the bad data detection(BDD)mechanism,leading to incorrect results of power system state estimation(PSSE).This paper presents a detection framework of FDIA for PSSE based on graph edge-conditioned convolutional networks(GECCN),which use topology information,node features and edge *** deep graph architecture,the correlation of sample data is effectively mined to establish the mapping relationship between the estimated values of measurements and the actual states of power *** addition,the edge-conditioned convolution operation allows processing data sets with different graph *** studies are undertaken on the IEEE 14-bus system under different attack intensities and degrees to evaluate the performance of *** results show that GECCN has better detection performance than convolutional neural networks,deep neural net-works and support vector ***,the satisfactory detection performance obtained with the data sets of the IEEE 14-bus,30-bus and 118-bus systems verifies the effective scalability of GECCN.

关键词： Power system state estimation(PSSE) Bad data detection(BDD) False data injection attacks(FDIA) Graph edge-conditioned convolutional networks(GECCN)

Improving high-temperature mechanical properties of cast CrFeCoNi high-entropy alloy by highly thermostable in-situ precipitated carbides

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 2021年第13期72卷 29-38页

作者： X.W.Liu N.Gao J.Zheng y.wu y.y.Zhao q.Chen W.Zhou S.Z.Pu W.M.Jiang Z.T.Fan State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621999China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China School of Materials Engineering Purdue UniversityWest LafayetteIN 47907USA Southwest Technology and Engineering Research Institute Chongqing 400039China Center for Electron Microscopy Wuhan UniversityWuhan 430072China

The Cr Fe Co Ni high-entropy alloy(HEA)exhibits excellent mechanical properties at lower temperatures due to its low stacking-fault energy,however,its medium-and high-temperature strengths are still *** consideration of the potential diversified applications,more strengthening approaches except for the previously proposed L12 phase hardening deserve further exploration due to its rapid coarsening tendency at high ***,we achieved significant high-temperature strengthening of the cast Cr Fe Co Ni HEA by in-situ precipitation of highly thermostable *** with 0.5 at.%and 1 at.%niobium and carbon were prepared by simple casting processes,*** cast,solute solution and aging.A highly thermostable microstructure was formed,which comprises very coarse grains accompanied with extensive thermostable carbide precipitates embedded,including submicrometer coherent Nb C particles in grain interiors and intergranular coherent M_(23)C_(6)*** high thermostability of microstructure,which is beneficial for the high-temperature loading,is ascribed to the synergy of lacking growth driving force and Zenner pinning effect by the *** properties tested at 673,873 and1073 K show that the yield strength and ultimate tensile strength are significantly increased by Nb/C doping,along with the elongation escalation at higher *** strengthening is mainly due to the precipitation hardening of carbide particles.

关键词： High-entropy alloy Carbides Precipitation High-temperature property Strengthening

Stochastic Accelerated Alternating Direction Method of Multipliers for Hedging Communication Noise in Combined Heat and Power Dispatch

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2023年第2期9卷 696-706页

作者： Zhigang Li Xinyu Liang Fan Hu Wen Xiong Renbo wu J.H.Zheng q.H.wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China Guangzhou Power Supply Bureau Guangdong Power Grid Co.LtdGuangzhouChina

Combined heat and power dispatch(CHPD)opens a new window for increasing operational flexibility and reducing wind power *** power and district heating systems are independently controlled by different system operators;therefore,a decentralized solution paradigm is necessary for CHPD,in which only minor boundary information is required to be exchanged via a communication ***,a nonideal communication environment with noise could lead to divergence or incorrect solutions of decentralized *** bridge this gap,this paper proposes a stochastic accelerated alternating direction method of multipliers(SA-ADMM)for hedging communication noise in *** algorithm provides a general framework to address more types of constraint sets and separable objective functions than the existing stochastic *** from the single noise sources considered in the existing stochastic approximation methods,communication noise from multiple sources is addressed in both the local calculation and the variable update *** studies of two test systems validate the effectiveness and robustness of the proposed SAADMM.

关键词： Alternating direction method of multipliers combined heat and power dispatch communication noise decentralized optimization

Multiple Tin Compounds Modified Carbon Fibers to Construct Heterogeneous Interfaces for Corrosion Prevention and Electromagnetic Wave Absorption

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第1期17卷 507-527页

作者： Zhiqiang Guo Di Lan Zirui Jia Zhenguo Gao Xuetao Shi Mukun He Hua Guo Guanglei wu Pengfei yin College of Science Sichuan Agricultural UniversityYa’an 625014People’s Republic of China School of Materials Science and Engineering Hubei University of Automotive TechnologyShiyan 442002People’s Republic of China Institute of Materials for Energy and Environment State Key Laboratory of Bio‑Fibers and Eco‑TextilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071People’s Republic of China Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’anShaanxi 710072People’s Republic of China

Currently,the demand for electromagnetic wave(EMW)absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly ***-component interface engineering is considered an effective means to achieve high-efficiency EMW ***,interface modulation engineering has not been fully discussed and has great potential in the field of EMW *** this study,multi-component tin compound fiber composites based on carbon fiber(CF)substrate were prepared by electrospinning,hydrothermal synthesis,and high-temperature thermal *** utilizing the different properties of different substances,rich heterogeneous interfaces are *** effectively promotes charge transfer and enhances interfacial polarization and conduction *** prepared SnS/SnS_(2)/SnO_(2)/CF composites with abundant heterogeneous interfaces have and exhibit excellent EMW absorption properties at a loading of 50 wt%in epoxy *** minimum reflection loss(RL)is−46.74 dB and the maximum effective absorption bandwidth is 5.28 ***,SnS/SnS_(2)/SnO_(2)/CF epoxy composite coatings exhibited long-term corrosion resistance on q235 steel ***,this study provides an effective strategy for the design of high-efficiency EMW absorbing materials in complex and harsh environments.

关键词： Electrostatic spinning Component regulation Heterogeneous interfaces Electromagnetic wave absorption Corrosion protection

First-Principles Study of the Influence of Lattice Misfit on the Behavior and the Ductility Effect of Hafnium in Ni-Ni3AI System

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2014年第1期27卷 87-94页

作者： y. wu J. Guo W. Zhang X. Ma q. Zhang J. Hou R. Huang X. Liu Institute of Molecular Engineering and Applied Chemistry Anhui University of Technology Ma'anshan 243002 China Shenyang National Laboratory for Materials Science Instituteof Metal Research Chinese Academy of SciencesShenyang 110016 China College of Physics Science and Technology Shenyang NormalUniversity Huanghe Street 253 Shengyang 110034 China School of Materials Science and Engineering Anhui Universityof Technology Ma'anshan 243002 China

Two Ni/Ni3Al-interface-contained cluster models with/without lattice misfit are studied by first-principles method to clarify the debates about the segregation behaviors of Hafnium （Hf） and explore the influence of lattice misfit on the ductility effect of Hr. It is found that though Hf prefers to substitute A1 rather than Ni in Ni3A1 phase within most of the investigated misfit range, its stronger preferring to Ni phase than NiaA1 phase makes it impossible to go into Ni3A1 phase to occupy A1 site in Ni-Ni3A1 alloys. Bond order analysis in Hf-free case shows that lattice misfit has different effects on the Griffith work of interfacial cleavage 27int/E and the maximum theoretical shear stress Zmax of Ni and Ni3A1, contributing to the existence of anomalous strength-temperature phenomena in NiaA1 alloys. However, the addition of Hf will make the 27int/E （or Zmax） of both Ni3A1 and Ni decrease （or increase） with lattice misfit, indicating that the addition of Hf may make the anomalous strength-temperature relationship in Ni3A1 region disappear locally.

关键词： Hafnium Lattice misfit Segregation Ductility

Deformation behavior of Mg-y-Ni alloys containing different volume fraction of LPSO phase during tension and compression through in-situ synchrotron diffraction

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第9期12卷 3631-3645页

作者： S.Z.wu y.q.Chi G.Garces X.H.Zhou H.G.Brokmeier X.G.qiao M.y.Zheng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Electromechanical Engineering Guangdong University of TechnologyGuangzhou 510006China Department of Physical Metallurgy CENIM-CSICAvenida Gregorio del Amo 828040 MadridSpain Institute of Materials Science and Engineering Clausthal University of TechnologyAgricolastrasse 6D-38678 Clausthal-ZellerfeldGermany

The deformation behavior of the as-extruded Mg-y-Ni alloys with different volume fraction of long period stacking ordered(LPSO)phase during tension and compression was investigated by in-situ synchrotron *** micro-yielding,macro-yielding,tension-compression asymmetry and strain hardening behavior of the alloys were explored by combining with deformation *** micro-yielding is dominated by basal slip of dynamic recrystallized(DRXed)grains in tension,while it is dominated by extension twinning of non-dynamic recrystallized(non-DRXed)grains in *** macro-yielding,the non-DRXed grains are still elastic deformed in tension and the basal slip of DRXed grains in compression are ***,the LPSO phase still retains elastic deformation,but can bear more load,so the higher the volume fraction of hard LPSO phase,the higher the tensile/compressive macro-yield strength of the *** from the low volume fraction of the non-DRXed grains and the delay effect of LPSO andγphases on extension twinning,the as-extruded alloys exhibit excellent tension-compression *** the volume fraction of LPSO phase reaches∼50%,tension-compression asymmetry is reversed,which is due to the fact that the LPSO phase is stronger in compression than in *** tensile strain hardening behavior is dominated by dislocation slip,while the dominate mechanism for compressive strain hardening changes from twinning in theα-Mg grains to kinking of the LPSO phase with increasing volume fraction of LPSO *** activation of kinking leads to the constant compressive strain hardening rate of∼2500 MPa,which is significantly higher than the tensile strain hardening rate.

关键词： Mg-y-Ni alloys LPSO phase In-situ synchrotron diffraction Micro-yielding Tensile-compression asymmetry Strain hardening