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Rare Metals 2021年第4期40卷 885-896页

作者： Hao Wu Qiu-Lin Li Ben Xu Hai-long Liu guo-Gang Shu wei Liu Graduate School at Shenzhen Tsinghua UniversityShenzhen 518055China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Nuclear Power Safety Monitoring Technology and Equipment China Nuclear Power Engineering Co.LtdShenzhen 518172China

The irradiation resistance of pre-deformed FeCu alloy was studied using a 3 MeV Fe ion irradiation experiment at room temperature in comparison with that of the as-received *** and atom probe tomography(APT) were used to characterize the mechanical properties and solute *** stress-strain curve obtained by nanoindentation shows that the yield strength(σ0.2) of the pre-deformed sample is unexpectedly reduced with an increase in the irradiation dose to five displacements per atom(dpa).We suggest that it results both from the decrease in the dislocation density and the suppression of defects during *** shows that the nucleation of the Cu cluster is suppressed;however,its growth is promoted in the pre-deformed sample,resulting in the formation of sparse and coarse clusters at 1 dpa *** coarse Cu clusters were then unexpectedly refined to finer grains with an increase in the irradiation dose to 5 ***,the improvement in the resistance to irradiation in the pre-deformed sample is attributed to the dense point-defect sinks,that is,the dislocations and grain boundaries introduced by *** addition,the contributions of the dislocations and grain boundaries to the sink strength are estimated for both the as-received and pre-deformed *** results indicate that dislocations,rather than grain boundaries,play a major role after deformation.

关键词： Reactor pressure vessel Irradiation damage Pre-deformation Dislocation density Cu-rich clusters

Microstructures and Plane Energy Spectra of X80 Pipeline Steel Welded Joints by Submerged Arc Automatic Welding

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Journal of Wuhan University of Technology(Materials Science) 2014年第6期29卷 1265-1269页

作者：孔德军 YE Cundong guo wei WU Yongzhong long Dan College of Mechanical Engineering Changzhou University Jiangsu Key Laboratory of Materials Surface Science and Technology Changzhou University

X80 pipeline steel was welded with submerged arc automatic welding, the microstructures, cavity sizes, fusion depths and plane scanning of chemical elements in the welded zone, fusion zone, heat affected zone and base steel were observed with OM（optical microscope） and SEM（scanning electron microscope）, respectively. The experimental results show that there is main acicular ferrite in the base steel and welded zone, the microscopic structure of fusion zone is a blocked bainite, and the heat affected zone is composed of multilateral ferrite and pearlite. M-A unit of the welded zone is the main factor to strengthen the welded zone, composed of acicular ferrites. The percentage of cavities in the welded joint is less than that in the base steel, which is beneficial to increasing its mechanical performance and corrosion resistance. The fusion depth in the fusion zone and welded zone is 101.13 μm and 115.85 μm, respectively, and the distribution of chemical elements in the welded zone is uniform, no enrichment phenomena.

关键词： X80 pipeline steel submerged arc automatic welding microstructure fusion depth plane scanning

Comparative Study on Solid-State and Metastable Liquid-State Aging for SAC305/Cu Joints

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Acta Metallurgica Sinica(English Letters) 2019年第5期32卷 629-637页

作者： Shuang Li Xiao-Wu Hu wei-guo Zhang Yu-long Li Xiong-Xin Jiang Key Lab for Robot and Welding Automation of Jiangxi Province Mechanical and Electrical Engineering SchoolNanchang University College of Mechanical and Electronic Engineering Northwest A&F University

In order to study the in?uence of the physical state of solder on the interfacial reaction of dip-soldered Sn-3.0 Ag-0.5 Cu/Cu system, two kinds of experiments were designed, including:(1) solid-state aging between the solder and Cu substrate;(2)liquid-state aging between the metastable supercooled liquid-state solder and Cu substrate. The aging times were 30, 60,120 and 180 min, respectively, and the aging temperature was 8 ℃ lower than the melting point of the Sn-3.0 Ag-0.5 Cu(SAC305) alloy(217 ℃). The experimental data revealed that the physical state of the solder obviously affected the formation of the intermetallic compound(IMC), and resulted in the difference in the diffusion of atoms on the interface between the SAC305 solder and Cu substrate. The IMC interface after aging for 30 min presents unique characteristics compared with that of the sample after dip soldering. The IMC interface of solid-state aged SAC305/Cu couple is relatively planar, while the IMC interface under metastable supercooled liquid-state aging conditions presents scallop-like shape.

关键词： Lead-free solder Supercooling Metastable liquid state Aging Intermetallic compound

Influences of Mechanical Vibration on Rapidly Solidified Al_2O_3/YSZ Ceramics Prepared by Combustion Synthesis

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Chinese Journal of Aeronautics 2006年第B12期19卷 27-30页

作者： ZHAO Zhong-min ZHANG long WANG wei-guo ZHANG Shi-yue Institute of Advanced Materials Mechanical Engineering College Shijiazhuang 050003 China Science Research Department Mechanical Engineering College Shijiazhuang 050003 China Foreign Training Department Mechanical Engineering College Shijiazhuang 050003 China

Al2O3/YSZ composite ceramics was fabricated with combustion synthesis technology, and the influences of mechanical vibration on its microstructures and properties were investigated. It is found that under the mechanical vibration of ever-increasing frequency, increasing combustion temperature, accelerating ceramics/metal liquid-liquid separation and quickening ceramic solidification could not only reduce the average diameter and the size distribution of aligned ZrO2 nano-micron fibers in rod-shaped Al2O3 matrix grains, but also make the randomly-oriented rod-shaped grains finer and increase their aspect ratios. As a result, a remarkable increase in flexural strength and fracture toughness of the ceramics can be observed.

关键词： ceramic matrix composite combustion synthesis rapid solidification nanocrystalline microstructure mechanical vibration

Entrance Effect on Load Capacity of Orifice Compensated Aerostatic Bearing with Feeding Pocket

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Chinese Journal of Mechanical Engineering 2010年第4期23卷 451-459页

作者： long wei BAO Gang School of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China

The current research of the aerostatic thrust bearing mainly focuses on the porous material bearing and inherent compensated air bearing, which aims at obtaining small physical dimension and large load capacity. Although porous material bearing appears larger load capacity, materials anisotropy itself and void content distortion caused in heat-treating, and machining processes add greater complexity to internal flow transfer process. Inherent compensated air bearing has the advantages of simple structure and good stability, but its load capacity and static stiffness is not worth somewhat. In this paper, based on hydrostatic lubrication theory, finite volume method is presented for taking entrance effects into account in computing pressure distribution, load capacity and mass flow rates of circular aerostatic thrust bearings. Technical analysis, numerical simulations and laboratory demonstration tests of influence of pocket diameter and pocket depth on loading capacity of aerostatic thrust bearing are carried out on simple orifice compensated air bearings with feeding pockets. The static parameters, such as air consumption and pressure distributions, are measured as a function of supply pressure and air gap height for several different orifices and pockets size. Entrance effects are described in term of typical throttling types, and the effect of pocket diameter and pocket depth on load capacity is systematically described respectively. The proposed research results uncover the causation of throttling action of the orifice compensated air bearing with feed pocket and further develop and improve the design theory of air bearing.

关键词： aerostatic thrust bearing feeding pocket entrance effects

Detection and analysis of magnetic particle testing defects on heavy truck crankshaft manufactured by microalloyed medium-carbon forging steel

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Journal of Iron and Steel Research International 2020年第5期27卷 608-616页

作者： Jin-long Lu guo-guang Cheng Meng Wu guo Yang Ju-long Che State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Research and Development Department Xining Special Steel Co.Ltd.Xining 810005QinghaiChina

An unqualifed six-cylinder heavy truck crankshaft has been studied to investigate the cause of magnetic particle testing defects on the rod ***-sized long-striped MnS inclusions are regarded as the major cause for the magnetic particle testing failure because they have been detected in situ under the magnetic particle *** the observation of macroscopic structures of the rod journals and corresponding counterweight blocks,it is found that for the 1#and 3#rod journals,the center metal of the original hot-rolled bar has been extruded to the inboard edge of the rod journals and large-sized long-striped MnS inclusions are exposed on the surface after fash removal,leading to the failure of magnetic particle *** for the 2#rod journal,the center metal of the original bar has not been extruded to the surface and MnS inclusions on the rod journal surface are small in size,few in number,resulting in passing the magnetic particle *** the quality of the hot-rolled bars fuctuates,it is more recommended to apply magnetic particle testing on samples at the center of bars before forging to evaluate the severity of defects caused by the long-striped MnS inclusions for fear of the scrap of the fnal crankshafts.

关键词： Crankshaft Magnetic particle testing MnS inclusion Microalloyed medium-carbon forging steel Defect

Formulization of Three-Dimensional Stress and Strain Fields at Elliptical Holes in Finite Thickness Plates

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Acta Mechanica Solida Sinica 2019年第4期32卷 393-430页

作者： wei guo Wcinlin guo State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016 China

Stress raisers such as holes are inevitable in structures at which stress concentration occurs and the static as well as fatigue strength of the structures can be significantly weakened. Therefore, to accurately evaluate the stress concentration factor and stress fields at holes is of essential importance for structure design and service life prediction. Although stress and strain concentration and fields at holes in finite thickness plates strongly change with and along the thickness, manuals of stress concentration for engineering design are mainly based on twodimensional theory and no explicit formula is available even for circular holes in finite thickness plates. Here we obtain for the first time a complete set of explicit formulae for stress and strain concentration factors and the out-of-plane constraint factor at circular as well as elliptical holes in finite thickness plates by integrating comprehensive three-dimensional finite element analyses and available theoretical solutions. The three-dimensional stress distributions ahead of holes can also be predicted by the obtained formulae. With their accuracy and the corresponding applicable range being analyzed and outlined in detail, the formulae can serve as an important fundamental solution for three-dimensional engineering structure design and guideline for developing threedimensional analytical methods.

关键词： Three-dimensional stress and strain concentration Stress field Elliptical holes Finite thickness plate Explicit solution

Antiosteoporosis and bone protective effect of alpinumisoflavone in steroid-induced osteoporosis rats via alteration of apoptosis,inflammatory and RANK/RANKL/OPG signaling pathway

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Asian Pacific Journal of Tropical Biomedicine 2024年第10期14卷 436-447页

作者： Jie Lian Jun-long Qu guo-wei Zhao Xu-Biao Ji Department of Orthopaedics Luzhou Traditional Chinese Medicine HospitalLuzhouSichuan646000China Department of Orthopedic Rehabilitation Shengli Oilfield Central HospitalDongyingShandong257000China Department of Spinal Surgery Changzhou Wujin People's HospitalWujin Hospital Affiliated with Jiangsu UniversityChangzhouJiangsu213000China

Objective:To estimate the bone protective effect of alpinumisoflavone,a natural prenylated isoflavonoid,against glucocorticoid-induced osteoporosis in ***:Male Wistar rats received intramuscular administration of dexamethasone(4 mg/mL)at a dose level of 7 mg/kg for 5 weeks,and then alpinumisoflavone(5,10,and 15 mg/kg)and alendronate(2 mg/kg)from 2 *** body weight and organ weight(femoral,vagina,and uterus)were *** analysis,bone turnover markers,bone parameters,oxidative stress parameters,and inflammatory cytokines were *** expressions of related genes were also ***:Alpinumisoflavone remarkably boosted body weight and organ weight(ureters and vagina),improved microCT analysis parameters,and boosted levels of bone ***,alpinumisoflavone considerably(P<0.001)restored the level of bone turnover markers and oxidative stress parameters,remarkably suppressed the level of cytokines such as interleukin-1β,interleukin-6,tumor necrosis factor-α,and increased transforming growth factor-βand insulin-like growth *** also significantly restored the osteoprotegerin(OPG,RANKL,and OPG/RANKL ratio)levels and the mRNA expression of Caspase(3,6,7,9),BMPs,OPN,ALP,RUNX2,and ***:The current result suggests the bone protective effect of alpinumisoflavone against glucocorticoid-induced osteoporosis in rats.

关键词： Osteoporosis Alpinumisoflavone Bone parameters Inflammation Oxidative stress

Jetting-based bioprinting:process,dispense physics,and applications

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Bio-Design and Manufacturing 2024年第5期7卷 771-799页

作者： wei long Ng Viktor Shkolnikov Singapore Centre for 3D Printing(SC3DP) School of Mechanical and Aerospace EngineeringNanyang Technological University(NTU)Singapore 639798Singapore HP Inc. Palo AltoCA 94304USA

Jetting-based bioprinting facilitates contactless drop-on-demand deposition of subnanoliter droplets at well-defined positions to control the spatial arrangement of cells,growth factors,drugs,and biomaterials in a highly automated layer-by-layer fabrication *** to its immense versatility,jetting-based bioprinting has been used for various applications,including tissue engineering and regenerative medicine,wound healing,and drug development.A lack of in-depth understanding exists in the processes that occur during jetting-based *** review paper will comprehensively discuss the physical considerations for bioinks and printing conditions used in jetting-based *** first present an overview of different jetting-based bioprinting techniques such as inkjet bioprinting,laser-induced forward transfer bioprinting,electrohydrodynamic jet bioprinting,acoustic bioprinting and microvalve ***,we provide an in-depth discussion of various considerations for bioink formulation relating to cell deposition,print chamber design,droplet formation and droplet ***,we highlight recent accomplishments in jetting-based *** present the advantages and challenges of each method,discuss considerations relating to cell viability and protein stability,and conclude by providing insights into future directions of jetting-based bioprinting.

关键词： 3D bioprinting Biofabrication Jetting-based Dispense physics Machine learning

Physical Properties of Polymers under Soft and Hard Nanoconfinement: A Review

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Chinese Journal of Polymer Science 2020年第6期38卷 565-578页

作者： Ming-Chao Ma Yun-long guo University o f Michigan-Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai200240China

Polymeric materials under nanoconfinements have substantially deviated physical properties with respect to the bulk,especially glass transition temperature,physical aging,and crystallization *** we highlight the leading methods for creating various confinement *** these systems,recent advances on hard and soft confinement effect for glass transition,physical aging,mechanical properties and crystallization of polymers are reviewed in ***,as nanoconfined systems in extreme conditions are experimentally inaccessible,simulation results describing confinement effect on such systems are also discussed.

关键词： Nanoconfinement Glass transition temperature Physical aging Mechanical properties Crystallization