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International Journal of Minerals,Metallurgy and Materials 2021年第7期28卷 1215-1223页

作者： Dao-ying Chen Ying Liu Ren-quan Wang jin-wen ye School of Materials Science and Engineering Sichuan UniversityChengdu 610065China

A series of novel steel-Ti(C,N)composites was fabricated by spark plasma sintering(SPS)and subsequent heat *** hardness,indentation fracture resistance,and wear behaviour of the steel-Ti(C,N)composites were compared with those of the unreinforced samples,and their potentials were assessed by comparison with traditional cermet/hardmetal *** results showed that with the addi-tion of 20wt%Ti(C,N),the wear rates of the newly examined composites reduced by a factor of about 2 to 4 and were comparable to those of cermets and *** martensitic transformation of the steel matrix and the formation of in situ carbides induced by heat treatment en-hanced the wear *** the presence of excessive in situ carbides improved the hardness,the low indentation fracture resistance(IFR)value resulted in brittle fracture,which in turn resulted in poor wear ***,the operative wear mechanisms were *** study provides a practical and cost-effective approach to prepare steel-Ti(C,N)composites as potential wear-resistant materials.

关键词： iron-based composite spark plasma sintering heat treatment titanium carbonitride wear resistance

Microwave sintering of TiCN-based cermets prepared from electroless Co-coated(Ti,W,Mo,V)CN powders

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Rare Metals 2022年第12期41卷 4209-4216页

作者： Jia Pang Ying Liu jin-wen ye Zheng-Hua Tang Jie Wang School of Materials Science and Engineering Sichuan UniversityChengdu 610065China Key Laboratory of Advanced Special Material and Technology Ministry of EducationChengdu 610065China

In this study,the densification and microstructure evolution of microwave sintered(Ti,W,Mo,V)CN-30 wt%Co cermets,which was prepared from electroless cobalt-coated submicron(Ti,W,Mo,V)CN powders,were *** microwave sintering of mechanical milled powders as well as the conventional sintering of mechanical milled powders and Co-coated(Ti,M)CN powders was conducted as a *** results indicate that a slight densification is observed at sintering temperature of≤1100℃followed by a sharp shrinkage at the temperature range of 1200-1350℃due to the substantial formation of liquid phase at 1200℃.The 98.5%densification is obtained at 1375℃.Moreover,the samples sintered at 1375℃for 10 min have the micro structure with fine and homogeneous grains of about 700 *** to mechanical milling,electroless cobalt plating suppresses coalescence of neighboring grain at the solid-state sintering stage,thereby inhibiting grain *** mechanical properties of samples sintered at different temperatures for varied holding time were also discussed.

关键词： Microwave sintering Electroless plating TiCN-based cermets Microstructure

Grain Refining Efficiency of SHS Al-Ti-B-C Master Alloy for Pure Aluminum and Its Effect on Mechanical Properties

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Acta Metallurgica Sinica(English Letters) 2016年第8期29卷 742-747页

作者： Xu-Guang An Ying Liu jin-wen ye Lin-Zhi Wang Peng-Yue Wang School of Materials Science and Engineering Sichuan University Key Laboratory of Advanced Special Material and Technology Ministry of Education

A new Al-5Ti-0.75B-0.2C master alloy was successfully prepared by self-propagating high-temperature（SHS）reaction from an Al-Ti-B_4C system with molten *** and phase characterization of the prepared Al-5Ti-0.75B-0.2C master alloy show that the nearly spherical TiC particles,hexagonal or rectangular TiB_2 particles,and blocklike TiAl_3 particles distribute uniformly in the aluminum *** refining test on commercial pure aluminum indicates that Al-5Ti-0.75B-0.2C master alloy exhibits a better grain refining performance than Al-5Ti-lB master *** addition of 0.2 wt%Al-5Ti-0.75B-0.2C master alloy,the average grain size of a-Al can be effectively refined to160 ± 5 μm from about 3000 μm,and the tensile strength and elongation are increased by about 20%and 14.1%due to the grain refinement.

关键词： Aluminum Al-Ti-B-C master alloy Self-propagating high-temperature(SHS) Grain refinement Mechanical properties

Microstructure and mechanical properties improvements in cemented carbides by(Cr,Mo,Ta)_(2)(C,N) inhibitors

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Rare Metals 2021年第3期40卷 679-686页

作者： Jie Tang Ying Liu jin-wen ye Zhi-Nan Cao Shi-Qing Ma Xiao-Jiao Yang School of Materials Science and Engineering Sichuan UniversityChengdu 610065China Key Laboratory of Advanced Special Material and Technology Ministry of EducationChengdu 610065China

Grain growth inhibitors can effectively suppress the grain size of tungsten carbide(WC),and consequently improve the hardness and strength of the cemented carbides;however,the toughness,one of the most important properties,usually deteriorates with ***,(Cr,Mo,Ta)_(2)(C,N) synthesized by carbothermal reductionnitridation was used as a novel inhibitor,and its effects on the microstructure and mechanical properties of the cemented carbides were *** results showed that the cemented carbides containing(Cr,Mo,Ta)_(2)(C,N)outperformed its counterpart comprising the traditional inhibitors in comprehensive mechanical properties,which was mainly attributed to the better inhibition performance provided by the(Cr,Mo,Ta)_(2)(C,N) solid-solution *** the content of(Cr,Mo,Ta)_(2)(C,N) increasing from 0 wt% to 1.25 wt%,the average grain size of WC in the cemented carbides decreased from 0.85 to 0.60 μm firstly,and then increased to 0.64 μ*** 1.00 wt%(Cr,Mo,-Ta)_(2)(C,N) addition,the cemented carbides with the best performance of hardness(HV_(30)) of 15.55 GPa,transverse rupture strength of 4272 MPa,fracture toughness of13.91 MPa·m1/2 were *** electron backscattered diffraction(EBSD) measurements showed that cemented carbides with(Cr,Mo,Ta)_(2)(C,N) processed more amount of∑2 boundary compared with the other specimens,which contributed to better fracture resistance.

关键词： Cemented carbides Microstructure Mechanical properties (Cr,Mo,Ta)_(2)(C,N) Electron backscattered diffraction(EBSD)

Microstructure and mechanical properties of WC-(Ti,M)(C,N)-Co cemented carbides with different nitrogen contents

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Rare Metals 2022年第10期41卷 3530-3538页

作者： Han-Jie Fan Ying Liu jin-wen ye Wei-Bin Qiu Yu-Chong Qiu School of Materials Science and Engineering Sichuan UniversityChengdu610065China

Three kinds of(Ti,M)(C_(1-x),N_(x))(M=Ta,Nb,W) quaternary solid-solution powders with various nitrogen contents were synthesized by carbothermal reductionnitridation(CRN) *** of nitrogen content on the microstructure and mechanical properties of WC-(Ti,M)(C_(1-x),N_(x))-Co cemented carbides fabricated by sinterhot isostatic pressing(HIP) were systematically investigated in this *** results show that the nitrogen content in the carbonitride raw powders strongly influences the morphology,the grain size and the compositions of the cemented *** the cemented carbides with different nitrogen contents have a similar microstructural appearance:weak core-rim structure consisting of solidsolution phase embedded in WC-Co *** is also observed that the carbonitride solid solution could somewhat reduce the WC grain growth,and the effectiveness of refining and the rim thickness are sensitively related to the nitrogen content of(Ti,M)(C_(1-x),N_(x)) solid *** addition,with an increase in the nitrogen content,mechanical properties of these hard metals are enhanced,which were discussed in terms of the constituent,the microstructure and the solution behavior of the carbonitride solid solutions.

关键词： Cemented carbides Solid-solution powders Nitrogen content Mechanical properties

Enhanced mechanical properties and formability of 316L stainless steel materials 3D-printed using selective laser melting

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International Journal of Minerals,Metallurgy and Materials 2019年第11期26卷 1396-1404页

作者： Xiao-qin Yang Ying Liu jin-wen ye Ren-quan Wang Ting-chuan Zhou Bin-yang Mao College of Materials Science and Engineering Sichuan University

This study is conducted to develop an innovative and attractive selective laser melting(SLM)method to produce 316 L stainless steel materials with excellent mechanical performance and complex part *** this work,the subregional manufacturing strategy,which separates the special parts from the components using an optimized process,was *** results showed that produced 316 L materials exhibited superior strength of^755 MPa and good *** the as-built parts,austenite with preferred orientation of the(220)plane,δ-ferrite,and a small amount of CrO phases were *** addition,the crystal size was fine,which contributed to the enhancement of the parts’mechanical *** structural anisotropy mechanism of the materials was also investigated for a group of half-sized samples with variable inclination *** technique was used to fabricate a set of impellers with helical bevels and high-precision planetary gears,demonstrating its strong potential for use in practical applications.

关键词： 316L stainless steel selective laser melting formability mechanical properties microstructure

UAV-assisted cooperative offloading energy efficiency system for mobile edge computing

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Digital Communications and Networks 2024年第1期10卷 16-24页

作者： Xue-Yong Yu wen-jin Niu ye Zhu Hong-Bo Zhu Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Nanjing210003China Engineering Research Centerof Health Service System Based on Ubiquitous Wireless Networks Ministry of EducationNanjng Universityof Posts and Telecommunications Nanjing210003China

Reliable communication and intensive computing power cannot be provided effectively by temporary hot spots in disaster areas and complex terrain ground *** this has greatly developed the application and integration of UAV and Mobile Edge Computing(MEC)to the Internet of Things(loT).However,problems such as multi-user and huge data flow in large areas,which contradict the reality that a single UAV is constrained by limited computing power,still *** to allowing UAV collaboration to accomplish complex tasks,cooperative task offloading between multiple UAVs must meet the interdependence of tasks and realize parallel processing,which reduces the computing power consumption and endurance pressure of *** the computing requirements of the user terminal,delay constraint of a computing task,energy constraint,and safe distance of UAV,we constructed a UAV-Assisted cooperative offloading energy efficiency system for mobile edge computing to minimize user terminal energy ***,the resulting optimization problem is originally nonconvex and thus,difficult to solve *** tackle this problem,we developed an energy efficiency optimization algorithm using Block Coordinate Descent(BCD)that decomposes the problem into three convex ***,we jointly optimized the number of local computing tasks,number of computing offloaded tasks,trajectories of UAV,and offloading matching relationship between multi-UAVs and multiuser *** results show that the proposed approach is suitable for different channel conditions and significantly saves the user terminal energy consumption compared with other benchmark schemes.

关键词： Computation offloading Internet of things(IoT) Mobile edge computing(MEC) Block coordinate descent(BCD)

General formalism for dirty extreme-mass-ratio inspirals

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 22-29页

作者： ye Jiang wen-Biao Han Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Shanghai Frontiers Science Center for Gravitational Wave Detection Shanghai 200240China

Detecting the environment around the supermassive black holes and tests of general relativity are important applications of extreme-mass-ratio inspirals(EMRIs).There is still a challenge to efficiently describe various“dirty”impacts on the inspirals,such as dark matter,gas,dipole radiation,and electromagnetic *** this study,we find the inherent linearity of the asymptotic solution of the inhomogeneous Teukolsky *** the basis of this property,we completely decouple the factors of the perturber and the background spacetime in the energy fluxes and *** the new decoupling form,the waveforms of EMRIs with non-geodesic motion in Kerr spacetime can be conveniently *** will help to resolve the environment(including gas,field,dark matter,electromagnetic interaction)around supermassive black holes and test general relativity.

关键词： gravitational wave Teukolsky equation extreme-mass-ratio inspirals

Noninvasive beam diagnosis based on the TM_(010)mode

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Nuclear Science and Techniques 2024年第7期35卷 115-125页

作者： Chuang-ye Song wen-Hui Huang Department of Engineering Physics Tsinghua University BeijingBeijing100084China of Education Beijing100084China

A resonant cavity based on the TM_(010)mode is an effective tool for noninvasive beam characterization. This technique has the advantages of a high signal-to-noise ratio, compact structure, and is related to multiple parameters compared with other beam monitors. In this study, high-precision measurements of the bunch charge, arrival time, bunch length, and energy parameters based on the TM_(010)mode are discussed. A cavity beam arrival time monitor(BAM) utilizing a phase cavity has been widely used in many facilities. Regarding bunch-length measurements, the influence of the beam energy, beam offset,and longitudinal spectrum on the TM_(010)mode are carefully considered to reduce errors, and the theoretical resolution of two cavities with different frequencies is analyzed. Owing to the dependence of the beam velocity of the beam loss factor, this method can also be used for the detection low beam energy using two cavities with the same frequency but different cavity lengths. A set of three cavities with different lengths and frequencies of 1.902 and 11.424 GHz is presented for measuring the four aforementioned parameters.

关键词： TM_(010)mode Noninvasive diagnosis Beam length Low energy

A self-centering and stiffness-controlled MEMS accelerometer

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Microsystems & Nanoengineering 2024年第1期10卷 27-40页

作者： Yiming jin Zhipeng Ma Ziyi ye Mingkang Li Xudong Zheng Zhonghe jin School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310013China Key Laboratory of Micro/Nano-Satellite Research of Zhejiang Province Hangzhou 310007PR China

This paper presents a high-performance MEMS accelerometer with a DC/AC electrostatic stiffness tuning capability based on double-sided parallel plates(DSPPs).DC and AC electrostatic tuning enable the adjustment of the effective stiffness and the calibration of the geometric offset of the proof mass,respectively.A dynamical model of the proposed accelerometer was developed considering both DC/AC electrostatic tuning and the temperature *** on the dynamical model,a self-centering closed loop is proposed for pulling the reference position of the forceto-rebalance(FTR)to the geometric center of *** self-centering accelerometer operates at the optimal reference position by eliminating the temperature drift of the readout circuit and nulling the net electrostatic tuning *** stiffness closed-loop is also incorporated to prevent the pull-in instability of the tuned low-stiffness accelerometer under a dramatic temperature ***-time adjustments of the reference position and the DC tuning voltage are utilized to compensate for the residue temperature drift of the proposed *** a result,a novel controlling approach composed of a self-centering closed loop,stiffness-closed loop,and temperature drift compensation is achieved for the accelerometer,realizing a temperature drift coefficient(TDC)of approximately 7μg/℃ and an Allan bias instability of less than 1μg.

关键词： stiffness electrostatic centering