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stability analyses of the mass abrasive projectile high-speed penetrating into a concrete target Part III: Terminal ballistic trajectory analyses

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Acta Mechanica sinica 2015年第4期31卷 558-569页

作者： H.Wu X.W.Chen q.Fang X.Z.Kong L.L.he Institute of systems Engineering China Academy of Engineering Physics state Key Laboratory for Disaster Prevention & Mitigation of Explosion & Impact PLA University of Science and Technology

During the high-speed penetration of projectiles into concrete targets （the impact velocity ranges from 1.0 to 1.5 km/s）, important factors such as the incident oblique and attacking angles, as well as the asymmetric abrasions of the projectile nose induced by the target-projectile interactions, may lead to obvious deviation of the terminal ballistic tra- jectory and reduction of the penetration efficiency. Based on the engineering model for the mass loss and nose-blunting of ogive-nosed projectiles established, by using the Differ- ential Area Force Law （DAFL） method and semi-empirical resistance function, a finite differential approach was pro- grammed （PENTRA2D） for predicting the terminal ballistic trajectory of mass abrasive high-speed projectiles penetrating into concrete targets. It accounts for the free-surface effects on the drag force acting on the projectile, which are attributed to the oblique and attacking angles, as well as the asymmetric nose abrasion of the projectile. Its validation on the prediction of curvilinear trajectories of non-normal high-speed pene- trators into concrete targets is verified by comparison with available test data. Relevant parametric influential analyses show that the most influential factor for the stability of ter- minal ballistic trajectories is the attacking angle, followed by the oblique angle, the discrepancy of asymmetric nose abrasion, and the location of mass center of projectile. The terminal ballistic trajectory deviations are aggravated as the above four parameters increase.

关键词： Projectile Penetration Concrete Massabrasion Terminal ballistic trajectory

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A reliability assessment method based on support vector machines for CNC equipment

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science China(Technological sciences) 2009年第7期52卷 1849-1857页

作者： WU Jun DENG Chao sHAO XinYu XIE s q school of Naval Architecture and Ocean Engineering Huazhong University of Science and TechnologyWuhan 430074China state Key Laboratory of Digital Manufacturing Equipment&Technology Huazhong University of Science and TechnologyWuhan 430074China Department of Mechanical Engineering University of AucklandAucklandNew Zealand

With the applications of high technology,a catastrophic failure of CNC equipment rarely occurs at normal operation *** it is difficult for traditional reliability assessment methods based on time-to-failure distributions to deduce the reliability *** paper presents a novel reliability assessment methodology to estimate the reliability level of equipment with machining performance degradation data when only a few samples are *** least squares support vector machines(Ls-sVM) are introduced to analyze the performance degradation process on the equipment.A two-stage parameter optimization and searching method is proposed to improve the Ls-sVM regression performance and a reliability assessment model based on the Ls-sVM is built.A machining performance degradation experiment has been carried out on an OTM650 machine tool to validate the effectiveness of the proposed reliability assessment methodology.

关键词： reliability assessment least squares support vector machines performance degradation radial basis function parameter optimization

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EMBRITTLEMENT OF A Cr-Mo LOW-ALLOY sTEEL DUE TO LOW-TEMPERATURE NEUTRON IRRADIATION

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Acta Metallurgica sinica(English Letters) 2006年第1期19卷 20-26页

作者： s.H. song L. q. Weng Department of Materials science and Engineering Shenzhen Graduate School HarbinInstitute of Technology Shenzhen 518055 China

Embrittlement of a Cr-Mo2.25CrlMo steel stemming from neutron irradiation at 270℃ is studied by virtue of small punch testing in conjunction with scanning electron microscopy. The ductile-brittle transition temperature determined by the small punch test is much lower than that determined by the standard Charpy test. There is some irradiation-induced embrittlement effect after the steel is irradiated for 46 days with a neutron dose rate of 1.05×10^18dpa/s （displacement per atom per second）.

关键词： irradiation embrittlement segregation low alloy steels pressure vessel

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Active{1121}and{1012}extension twinning in a WE43 Mg alloy

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Journal of Materials science & Technology 2023年第13期144卷 93-101页

作者： W.q.Chen s.Deng X.J.Zhao s.N.Luo Key Laboratory of Advanced Technologies of Materials Ministry of EducationSouthwest Jiaotong UniversityChengdu 610031China The Peac Institute of Multiscale sciences Chengdu 610031China

Deformation twinning in a WE43 alloy subjected to uniaxial compression at room temperature is ***{1121}and{1012}extension twinning is *** activation of{1121}twinning in a certain grain is influenced not only by its own schmid factor,but also by that of the basal ***-twin interactions of the co-zone{1121}twin variants are commonly observed and systematically studied,including the crystallographic characteristics of the four typically observed twin-twin junctions(TTJs)and the associated twin-twin *** the quilted-looking TTJs formed by the interaction of co-zone{1012}twin variants,crossing-like TTJs of co-zone{1121}twin variants are observed and their formation mechanisms are ***-like TTJs are also formed by the interaction of{1121}and{10¯12}*** morphology and thickening rate of{1121}and{1012}twins vary markedly due to the difference in twinning *** needle-like{1121}twins thicken more slowly than the lenticular{1012}*** nucleation is observed on the previously formed{1121}twin boundary due to the relatively large strain concentration on such interface,while twin nucleation on{1012}twin boundary is rarely observed.

关键词： Mg alloy Plastic deformation Twinning Twin-twin interaction Twin-twin junction

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heat transfer analysis in peristaltic flow of MHD Jeffrey fluid with variable thermal conductivity

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Applied Mathematics and Mechanics(English Edition) 2015年第4期36卷 499-516页

作者： q.HUssAIN s.AsGHAR T.HAYAT A.ALsAEDI Department of Mathematics COMSATS Institute of Information Technology Nonlinear Analysis and Applied Mathematics (NAAM) Research Group Faculty of ScienceKing Abdul Aziz University Department of Mathematics Quaid-i-Azam University

The effect of an inclined magnetic field in the peristaltic flow of a Jeffrey fluid with variable thermal conductivity is discussed. The temperature dependent thermal conductivity of fluid in an asymmetric channel is taken into account. A dimensionless nonlinear system subject to a long wavelength and a low Reynolds number is solved. The explicit expressions of the stream function, the axial velocity, the pressure gradient, and the temperature are obtained. The effects of all physical parameters on peristaltic transport and heat transfer characteristics are observed from graphical illustrations. The behaviors of θ∈ [0, π/2] and θ∈ [π/2, π] on fluid flow and heat transfer are found to be opposite. Further, the size of trapped bolus is greater for the case of the inclined magnetic field （θ≠ π/2） than that for the case of the transverse magnetic field （θ = π/2）. The heat transfer coefficient decreases when the constant thermal conductivity （Newtonian） fluid is changed to the variable thermal conductivity （Jeffrey） fluid.

关键词： inclined magnetic field variable thermal conductivity Jeffrey fluid peri-staltic transport heat transfer

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Template-free Fabrication and Luminescent Characterization of Highly Uniform and Monodisperse Y_2O_2s:sm^(3+) Hollow submicrospheres

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Journal of Materials science & Technology 2012年第7期28卷 666-672页

作者： s.q. Deng Z.P. Xue Y.H. Yang q. Yang Y.L. Liu Department of Chemistry Jinan University Guangzhou 510632 China

Well dispersed and homogeneous Y2O2s：sm3＋ hollow submicrospheres were successfully achieved by a template- free solvothermal method combining with a postcalcining process. The crystalstructure and particle morphology were investigated by the X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） spectra, scanning and transmission electron microscopy （sEM and TEM）, respectively. A possible growth mechanism was proposed to reveal the formation process. Luminescence properties of the Y202s：sm3＋ long-lasting phosphor were an- alyzed by measuring the excitation spectra, emission spectra, afterglow decay curve and thermoluminescence curve. The excitation spectra indicated that the phosphor could be excited effectively by the ultraviolet-light emitting diode （UV-LED） or blue LED, and the emission spectra showed that the phosphor could emit red light from 600 to 650 nm.

关键词： Yttrium oxysulfide Hollow submicrosphere Luminescence Long-lasting phosphor

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heat transfer in a porous saturated wavy channel with asymmetric convective boundary conditions

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Journal of Central south University 2015年第1期22卷 392-401页

作者： q.Hussain s.Asghar T.Hayat A.Alsaedi Department of Mathematics COMSATS Institute of Information Technology Department of Mathematics Faculty of Science King Abdulaziz University Department of Mathematics Quaid-I-Azam University 45320

The viscous flow in a wavy channel with convective boundary conditions is investigated. The channel is filled with a porous viscous fluid. Two cases of equal and different external convection coefficients on the walls are taken into account. Effect of viscous dissipation is also considered. The governing equations are derived employing long wavelength and low Reynolds number approximations. Exact closed form solutions are obtained for the simplified equations. Important physical features for peristaltic flow caused by the wavy wave are pumping, trapping and heat transfer rate at the channel walls. These are discussed one by one in depth and detail through graphical illustrations. special attention has been given to the effects of convective boundary conditions. The results show that for Bi1≠Bi2, there exists a critical value of Brinkman number Brc at which the temperatures of both the walls become equal. And, for Bi1>Bi2 and Br>Brc, the temperature of the cold wall exceeds the temperature of hot wall.

关键词： peristalsis heat transfer porous medium convective boundary conditions

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Effects of Current stressing on shear Properties of sn-3.8Ag-0.7Cu solder Joints

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Journal of Materials science & Technology 2010年第8期26卷 737-742页

作者： X.J. Wang q.L. Zeng q.s. Zhu Z.G. Wang J.K. shang shenyang National Laboratory for Materials science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Department of Materials science and Engineering University of Illinois at Urbana-Champaign Urbana IL 61801 USA

Effects of electromigration on microstructure, shear strength, and fracture behavior of solder joints were investigated by single-ball shear samples of eutectic sn-3.8Ag-0.7Cu （sAC） joined by Cu plates at two sides. The electromigration tests were conducted at a current density of about 1.1×10^3 A/cm2 and a working temperature of about 83℃. The results showed that the shear strength and flow stress decreased greatly after current stressing. such a decrease was associated with no significant loss of the fracture strain at short electromigration but a great reduction in the fracture strain after long-term current stressing. The variation of the fracture strain with the electromigration time was shown to result from the shift of the fracture surface from the center of the solder towards the intermetallic compound （IMC） interface at the cathode.

关键词： strength Fracture strain Voids solder

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The LIqUIDUs OF The TERNARY Ag-Cu-si ALLOY sYsTEM

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Acta Metallurgica sinica(English Letters) 1998年第5期11卷 325-328页

作者： Z.G.Liu X.M.Luo G.s.Guo C.X.he G.B.Li q.Y.Zhang Inst of Precious Metals Kunming China

The liquidus of the ternary Ag-Cd-si alloy system in the Ag-Cu rich region was determined by DTA. The ternary Ag-Cd-si system was divided into two ternary systems Ag-Cu-Cuo.76si0.24 and Ag-Cu0.76si0.24-si by the section of Ag-Cu0.76 *** is one ternary eutectic point for both the systems with the composition of 12. 5at. %Ag+71. 7at.%Cu+15.8at. %si and 30at.% Ag+44.7at.%Cu+25.3at.%sirespectivelg and the temperatures of the eutectic points are 740 and 705℃ respectively.

关键词： Ag-Cd-si ternary sytem liquidus

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Micro-sized and Nano-sized Fe_3O_4 Particles as Anode Materials for Lithium-ion Batteries

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Journal of Materials science & Technology 2011年第1期27卷 41-45页

作者： Y.X.Chen L.H.he P.J.shang q.L.Tang Z.q.Liu H.B.Liu L.P.Zhou College of Materials science and Engineering Hunan UniversityChangsha 410082China shenyang National Laboratory for Materials science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Micro-sized（1030.3±178.4 nm） and nano-sized（50.4±8.0 nm） Fe3O4 particles have been fabricated through hydrogen thermal reduction of α-Fe2O3 particles synthesized by means of a hydrothermal *** morphology and microstructure of the micro-sized and the nano-sized Fe3O4 particles were characterized by X-ray diffraction,field-emission gun scanning electron microscopy,transmission electron microscopy and highresolution electron *** micro-sized Fe3O4 particles exhibit porous structure,while the nano-sized Fe3O4 particles are solid *** electrochemical performance was also *** nano-sized solid Fe3O4 particles exhibit gradual capacity fading with initial discharge capacity of 1083.1 mAhg-1 and reversible capacity retention of 32.6% over 50 ***,the micro-sized porous Fe3O4 particles display very stable capacity-cycling behavior,with initial discharge capacity of 887.5 mAhg-1 and charge capacity of 684.4 mAhg-1 at the 50th ***,77.1% of the reversible capacity can be maintained over 50 *** micro-sized porous Fe3O4 particles with facile synthesis,good cycling performance and high capacity retention are promising candidate as anode materials for high energy-density lithium-ion batteries.

关键词： Lithium-ion battery Fe3O4 Porous structure Anode materials

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