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Journal of Iron and Steel Research International 2018年第10期25卷 1068-1077页

作者： Xin GUO pei-qing la Heng Li Yu-peng Wei Xue-feng Lu State Key laboratory of Advanced Processing and Recycling of Non-ferrous Metal Lanzhou University of Technology Lanzhou 730050 Gansu China Key laboratory of Nonferrous Metal Alloys and Processing Ministry of Education Lanzhou University of Technology Lanzhou 730050 Gansu China

Microstructure evolution and mechanical properties of 316L austenitic stainless steel with aluminum addition by warm rolling at 550 ℃ were investigated. It is found that sample is composed of an ashen austenite matrix, a gray black ferrite phase and a small number of NiCx. The average grain sizes are 21.62, 19.66 and 19.49 μm for samples with the rolling deformation of 30%, 50% and 70%, respectively. The yield strength and tensile strength of samples with solid solution time of 30 min and deformation of 70% are higher. The fracture modes are similar and belong to toughness fracture. The fracture surfaces of the samples are composed of relatively large equal-axis ductile dimples （5-15 μm） and fine scattered ones around the dimples （〈 5 μm）. As the rolling deformation increases, the quantity of subgrain boundary increases and the 〈 101 〉 orientation is more prominent. {001 } 〈 110 〉 rotation-cube textures are present in ferrite phase of samples and weak Goss texture is formed in austenite pole images.

关键词： AISI 316L austenitic stainless steel Warm rolling Tensile property Fracture mechanism Deformationtexture

Effects of Different Substrates on Microstructures and Mechanical Properties of a Bulk Nanocrystalline Structure Pure Iron Prepared by Aluminothermic Reaction Casting

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Journal of Iron and Steel Research International 2015年第4期22卷 324-329页

作者： Xiao-juan ZHEN pei-qing la Cui-ling LI Su-lei HU State Key laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of Technology

A simple method was developed to produce the nanocrystalline pure iron by aluminothermic reaction cast- ing. The mierostructure of the iron was investigated by optical microseope （OM）, transmission electron microscope （TEM）, electron probe micro-analyzer （EPMA）, scanning electron microscope （SEM） and X-ray diffraction （XRD）. The mechanical performances of nanoerystalline pure iron were tested. It is found that the pure iron consists of nanoerystalline ferrite. For different substrates of eopper and glass, the average grain size of the ferrite was 38 and 35 nm, respectively, which is larger on copper substrate than that on glass. The hardness, compressive strength, tensile strength, and total elongation are 167 and 137 HB, 400 and 500 MPa, 243 and 185 MPa, 16% and 10% on copper substrate and glass suhstrate, respectively. The hardness, tensile strength and total elongation are all larger on copper substrate than those on glass substrate, while the eompressive strength is lower. The large supercooling in the product solidification provides the condition for high nucleation rate and thus leads to nano-grained austenite and final nano-grained ferrite transformed from those small austenite grains.

关键词： nanocrystalline aluminothermic reaction casting pure iron substrate microstructure mechanical property

Achieving high strength in nanolaminate 1020 steel prepared by aluminothermic reaction through multiple warm rolling

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Achieving high strength in nanolaminate 1020 steel prepared ...

Migration for survival under natural disasters:A reluctant and passive choice for agriculturalists in historical China

钢铁流程绿色制造与创新技术交流会

作者： Zheng-ning LI Fu-an WEI pei-qing la Xin GUO Jie SHENG State Key laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology qinghai Provincial Key laboratory of New Light Alloys Qinghai Provincial Engineering Research Center of High Performance Light Metal Alloys and FormingQinghai University

large dimensional bulk 1020 carbon steel with nanolaminate pearlite was rolled at 600°C with different thickness *** the increase of thickness reduction,the dislocation density increased gradually,meanwhile the tensile strength improved *** possesses the key combination of three characteristics about high density dislocation,nanolamination,and second-phase *** results of microstructure observation and tensile test show that when the thickness reduction was 60%,most of the lamellar cementites were crushed to globular particles,the tensile strength reached 560 MPa,and the elongation is 14%.The present study provides an easy route to enhance the mechanical properties of these alloys,and it has a wide application potential.

关键词： deformation disclinations mechanical properties nanostructured materials

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Science China Earth Sciences 2017年第12期60卷 2089-2096页

作者： pei qing Department of Social Sciences the Education University of Hong KongHong KongChina

This study quantitatively investigates the long-term dynamics of the association between natural disasters and the migration of agriculturists in historical China. Population pressure is also studied because migration is a population density-dependent phenomenon. This study has adopted correlation analysis, multivariate linear/Poisson regression analyses, and Granger causality analysis to verify the linkages of natural disaster-migration and population-migration in historical China by collecting updated datasets. This study is the first attempt to reveal that the duration effects of natural disasters on the migration of agriculturalists are short-term and almost instantaneous. Although the agrarian society has a low buffering capacity, the effects of natural disasters within a short-term scale could be relieved to some extent. However, population pressure can push migration on a long-term scale despite its limited forcefulness.

关键词： Natural disasters Agriculturalists'migration Population pressure Empirical analysis Historical China

On well-posedness of two-phase nonlocal integral models for higher-order refined shear deformation beams

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Applied Mathematics and Mechanics(English Edition) 2021年第7期42卷 931-950页

作者： pei ZHANG Hai qing State Key laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Due to the conflict between equilibrium and constitutive requirements,Eringen’s strain-driven nonlocal integral model is not applicable to nanostructures of engineering *** an alternative,the stress-driven model has been recently *** this paper,for higher-order shear deformation beams,the ill-posed issue(i.e.,excessive mandatory boundary conditions(BCs)cannot be met simultaneously)exists not only in strain-driven nonlocal models but also in stress-driven *** well-posedness of both the strain-and stress-driven two-phase nonlocal(TPN-Strain D and TPN-Stress D)models is pertinently evidenced by formulating the static bending of curved beams made of functionally graded(FG)*** two-phase nonlocal integral constitutive relation is equivalent to a differential law equipped with two restriction *** using the generalized differential quadrature method(GDQM),the coupling governing equations are solved *** results show that the two-phase models can predict consistent scale-effects under different supported and loading conditions.

关键词： well-posedness strain-and stress-driven two-phase nonlocal(TPN-Strain D and TPN-Stress D)models refined shear deformation theory functionally graded(FG)curved beam generalized differential quadrature method(GDQM)

Two-phase nonlocal integral models with a bi-Helmholtz averaging kernel for nanorods

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Applied Mathematics and Mechanics(English Edition) 2021年第10期42卷 1379-1396页

作者： pei ZHANG Hai qing State Key laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In this work,the static tensile and free vibration of nanorods are studied via both the strain-driven(Strain D)and stress-driven(Stress D)two-phase nonlocal models with a bi-Helmholtz averaging *** adjusting the limits of integration,the integral constitutive equation of the Fredholm type is converted to that of the Volterra type and then solved directly via the laplace transform *** unknown constants can be uniquely determined through the standard boundary conditions and two constrained conditions accompanying the laplace transform *** the numerical examples,the bi-Helmholtz kernel-based Strain D(or Stress D)two-phase model shows consistently softening(or stiffening)effects on both the tension and the free vibration of nanorods with different boundary *** effects of the two nonlocal parameters of the bi-Helmholtz kernel-based two-phase nonlocal models are studied and compared with those of the Helmholtz kernel-based models.

关键词： two-phase nonlocal integral model bi-Helmholtz kernel tensile analysis free vibration exact solution laplace transform

电刺激诱导miR-741-3p调控Radil促进施万细胞的迁移

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中国组织工程研究 2025年第19期29卷 4038-4043页

作者：刘庆高博杨霄姜宇王培承德医学院附属医院河北省承德市067000 承德医学院河北省承德市067000

背景:越来越多的动物实验和临床研究证实电刺激可以促进周围神经损伤修复,具体的机制尚未完全明确。目的:探讨电刺激诱导miR-741-3p调控Radil对施万细胞迁移的影响。方法:①12只雄性SD大鼠,随机分为电刺激组和对照组,电刺激组在坐骨神... 详细信息

背景:越来越多的动物实验和临床研究证实电刺激可以促进周围神经损伤修复,具体的机制尚未完全明确。目的:探讨电刺激诱导miR-741-3p调控Radil对施万细胞迁移的影响。方法:①12只雄性SD大鼠,随机分为电刺激组和对照组,电刺激组在坐骨神经挤压伤后连续电刺激7 d,对照组在坐骨神经挤压后不做任何处理。术后第7天取损伤处神经,利用荧光原位杂交技术检测两组miR-741-3p的表达差异。②通过miRDB、TargetScan和miRWalk数据库预测miR-741-3p靶基因。③将miR-741-3p模拟物及其对照、miR-741-3p抑制物及其对照、Radil siRNA及其对照、miR-741-3p抑制物+Radil siRNA及miR-741-3p抑制物+siRNA对照对施万细胞进行转染,采用RT-PCR检测转染效率,Transwell小室检测施万细胞的迁移能力。结果与结论:①电刺激组神经残端miR-741-3p荧光强度低于对照组;②数据库预测结果显示有69个基因可能是miR-741-3p靶基因,Radil是预测靶基因之一,主要参与细胞黏附和迁移;③与miR-741-3p抑制物对照组相比,miR-741-3p抑制物组施万细胞迁移数增多(P<0.05);与miR-741-3p模拟物对照组相比,miR-741-3p模拟物组施万细胞迁移数减少(P<0.05);与siRNA对照组相比,Radil siRNA组施万细胞迁移数减少(P<0.05);④与miR-741-3p抑制物对照组相比,miR-741-3p抑制物组Radil的表达水平升高;与miR-741-3p模拟物对照组相比,miR-741-3p模拟物组Radil的表达水平降低;⑤与miR-741-3p抑制物+siRNA对照组相比,miR-741-3p抑制物+Radil siRNA组施万细胞迁移数减少(P<0.05)。结果表明,电刺激通过下调miR-741-3p调控Radi的表达来促进施万细胞迁移。

关键词：施万细胞电刺激 miR-741-3p Radil 细胞迁移神经再生

A General law of Moment Convergence Rates for Uniform Empirical Process

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Acta Mathematica Sinica,English Series 2011年第10期27卷 1941-1948页

作者： qing pei ZANG School of Mathematical Science Huaiyin Normal UniversityHuai'an 223300 P. R. China

Let {Xn; n ≥ 1} be a sequence of independent and identically distributed U[0,1]-distributed random variables. Define the uniform empirical process Fn（t） = n^-1/2 ∑^ni=1 （I{xi≤t} - t）, 0 ≤ t 〈 1, ││Fn││ = sup0≤t≤ 1 │Fn（t）│. In this paper, the exact convergence rates of a general law of weighted infinite series of E{││Fn││ -εg^s（n）}＋ are obtained.

关键词： Moment convergence rates uniform empirical process Brownian bridge

Effect of Hot Pressing on Microstructure and Mechanical Properties of Bulk Nanocrystalline Fe_3Al Materials Containing Manganese Element

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Journal of Iron and Steel Research International 2011年第3期18卷 65-71页

作者： LI Yu-feng la pei-qing WEI Yu-peng LU Yang YANG Yang State Key laboratory of Gansu Advanced Nonferrous Materials Lanzhou University of TechnologyLanzhou 730050GansuChina

Bulk nanocrystalline Fe3Al materials containing manganese of 10% were prepared by aluminothermic *** pressing of those materials was performed at different temperatures and *** microstructures of the alloy were investigated by optical microscope（OM） and electron probe microanalyzer（EPMA）.The grain sizes of the materials were analyzed by X-ray diffraction（XRD） and transmission electron microscope（TEM）.The results showed that the grain sizes of the materials increase after hot *** grain sizes of the materials decrease with increasing the hot pressing times at the same temperature and the grain sizes of the materials increase with increasing hot pressing temperatures at identical *** hardness and compressibility of the materials were also *** results showed that the hardness decreases with increasing hot pressing times at 800 ℃ and hardness increases with increasing the hot pressing *** variation of hardness with grain size of the nanocrystalline Fe3Al materials after hot pressing is contrary to the Hall-Petch *** materials are not broken during hot pressing and exhibit good plasticity and compressibility.

关键词： hot pressing Fe3Al nanostructure material microstructure mechanical property

SUBMERGED IMPINGING JETS WITHIN A FINITE WATER DEPTH

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Journal of Hydrodynamics 2002年第3期14卷 40-43页

作者： Liu, pei-qing Hydraulics lab. of High Speed Flows Sichuan Univ. Chengdu 610065 China Fluid Mech. Inst. Beijing Univ. of Aero. and Astron. Beijing 100083 China

By use of the sheet of laser light and the tracing particle technology, flow visualization tests of complex flow structures for submerged impinging jets within finite water depths are conducted. Typical flow patterns of submerged impinging jets are analysed by the singular topology method. In order to reveal the mechanism of these flows, the diffusive characteristics and turbulent fluctuations of submerged impinging jets are measured by the hot-film anemometer.

关键词： Anemometers Flow of fluids Flow visualization lasers Turbulence