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All-optical μ^- acceleration in the laser wakefield

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High Power Laser Science and Engineering 2018年第4期6卷 119-124页

作者： F.Zhang Z.g.Deng L.q.Shan Z.M.Zhang B.Bi D.X.Liu W.W.Wang Z.q.Yuan c.Tian S.q.Yang B.Zhang Y.q.gu Science and Technology on Plasma Physics Laboratory Laser Fusion Research CenterChina Academy of Engineering Physics IFSA collaborative Innovation center Shanghai Jiao Tong University

Muons produced by the Bethe–Heitler process from laser wakefield accelerated electrons interacting with high Z materials have velocities close to the laser wakefield. It is possible to accelerate those muons with laser wakefield *** for the first time we propose an all-optical ‘generator and Booster’ scheme to accelerate the produced muons by another laser wakefield to supply a prompt, compact, low cost and controllable muon source in laser laboratories. The trapping and acceleration of muons are analyzed by one-dimensional analytic model and verified by two-dimensional particle-in-cell(PIc) simulation. It is shown that muons can be trapped in a broad energy range and accelerated to higher energy than that of electrons for longer dephasing length. We further extrapolate the dependence of the maximum acceleration energy of muons with the laser wakefield relativistic factor γ and the relevant initial energy E_0. It is shown that a maximum energy up to 15.2 geV is promising with γ = 46 and E_0= 1.45 ge V on the existing short pulse laser facilities.

关键词： laser wakefield acceleration muon source

Effects of Vapor Pressure and Super-Hydrophobic Nanocomposite coating on Microelectronics Reliability

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Engineering 2015年第3期1卷 384-390页

作者： Xuejun Fan Liangbiao chen c.P.Wong Hsing-Wei chu g.q.Zhang Department of Mechanical Engineering Lamar University State Key Laboratory of Solid State Lighting School of Materials Science and Engineering Georgia Tech Delft University of Technology Institute of Semiconductors Chinese Academy of Sciences

Modeling vapor pressure is crucial for studying the moisture reliability of microelectronics, as high vapor pressure can cause device failures in environments with high temperature and humidity. To minimize the impact of vapor pressure, a super-hydrophobic(SH) coating can be applied on the exterior surface of devices in order to prevent moisture penetration. The underlying mechanism of SH coating for enhancing device reliability, however, is still not fully understood. In this paper, we present several existing theories for predicting vapor pressure within microelectronic materials. In addition, we discuss the mechanism and effectiveness of SH coating in preventing water vapor from entering a device, based on experimental results. Two theoretical models, a micro-mechanics-based whole-field vapor pressure model and a convection-diffusion model, are described for predicting vapor pressure. Both methods have been successfully used to explain experimental results on uncoated samples. However, when a device was coated with an SH nanocomposite, weight gain was still observed, likely due to vapor penetration through the SH surface. This phenomenon may cast doubt on the effectiveness of SH coatings in microelectronic devices. Based on current theories and the available experimental results, we conclude that it is necessary to develop a new theory to understand how water vapor penetrates through SH coatings and impacts the materials underneath. Such a theory could greatly improve microelectronics reliability.

关键词： vapor pressure moisture semiconductor reliability microelectromechanical systems (MEMS) superhydrophobic nanocomposite coating

geometrical shape of in-plane inclusion characterized by polynomial internal stress field under uniform eigenstrains

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Applied Mathematics and Mechanics(English Edition) 2016年第9期37卷 1113-1130页

作者： Jian WU c.q.RU Liang ZHANg Ling WAN college of Aerospace Engineering Chongqing University Department of Mechanical Engineering University of Alberta State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology

The internal stress field of an inhomogeneous or homogeneous inclusion in an infinite elastic plane under uniform stress-free eigenstrains is studied. The study is restricted to the inclusion shapes defined by the polynomial mapping functions mapping the exterior of the inclusion onto the exterior of a unit circle. The inclusion shapes, giving a polynomial internal stress field, are determined for three types of inclusions, i.e., an inhomogeneous inclusion with an elastic modulus different from the surrounding matrix, an inhomogeneous inclusion with the same shear modulus but a different Poisson＇s ratio from the surrounding matrix, and a homogeneous inclusion with the same elastic modulus as the surrounding matrix. Examples are presented, and several specific conclusions are achieved for the relation between the degree of the polynomial internal stress field and the degree of the mapping function defining the inclusion shape.

关键词： inclusion shape internal stress field eigenstrain polynomial

crack Initiation Mechanism of Z3cN20.09M Duplex Stainless Steel during corrosion Fatigue in Water and Air at 290 °c

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Journal of Materials Science & Technology 2015年第11期31卷 1144-1150页

作者： H.c.Wu B.Yang Y.Z.Shi q.gao Y.q.Wang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing collaborative Innovation center of Universal Iron & Steel Technology School of Materials Science and Engineering Anhui University of Technology

The crack initiation mechanism of a Z3cN20.09M duplex stainless steel （DSS） during corrosion fatigue （cF） in water and air at 290 ℃ was investigated by using a cF cracking machine and a scanning electron microscopy （SEM）. The cracks were initiated successively at the persistent stip bands （PSBs）, phase boundaries （PBs） and pitting corrosion points （PcPs） of the specimens when they were tested in water at 290 ℃, while in airat 290 ℃ the cracks were only initiated at the PSBs and PBs. And the cracks were found mainly to initiate at the PSBs and PBs when the specimens were tested in water and air at 290 ℃, respectively. The results also reveal that the cracks were likely to be initiated at the first 20% of fatigue life of the specimens tested in water at 290 ℃. However, the cracks were not found until 50% of fatigue life when tested in air at 290 ℃. Moreover, the crack numbers of the specimens tested in water at 290 ℃ were much more than those tested in air at 290 ℃.

关键词： Duplex stainless steel corrosion fatigue crack initiation High temperature water

Therapeutic uses of animal biles in traditional chinese medicine:An ethnopharmacological,biophysical chemical and medicinal review

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World Journal of gastroenterology 2014年第29期20卷 9952-9975页

作者： David q-H Wang Martin c carey gastroenterology Division Department of MedicineBrigham and Women’s HospitalHarvard Medical School and Harvard Digestive Diseases Center Liver center and gastroenterology Division Department of MedicineBeth Israel Deaconess Medical CenterHarvard Medical School and Harvard Digestive Diseases Center Division of gastroenterology and Hepatology Department of Internal MedicineEdward Doisy Research CenterSaint Louis University School of Medicine

Forty-four different animal biles obtained from both invertebrates and vertebrates (including human bile) have been used for centuries for a host of maladies in traditional chinese medicine (TcM) beginning with dog, ox and common carp biles approximately in the Zhou dynasty (c. 1046-256 BcE). Overall, different animal biles were prescribed principally for the treatment of liver, biliary, skin (including burns), gynecological and heart diseases, as well as diseases of the eyes, ears, nose, mouth and throat. We present an informed opinion of the clinical efficacy of the medicinal uses of the different animal biles based on their presently known principal chemical components which are mostly steroidal detergent-like molecules and the membrane lipids such as unesterified cholesterol and mixed phosphatidylcholines and sometimes sphingomyelin, as well as containing lipopigments derived from heme principally bilirubin glucuronides. All of the available information on the ethnopharmacological uses of biles in TcM were collated from the rich collection of ancient chinese books on materia medica held in libraries in china and United States and the composition of various animal biles was based on rigorous separatory and advanced chemical identification techniques published since the mid-20th century collected via library (Harvard’s countway Library) and electronic searches (PubMed and google Scholar). Our analysis of ethnomedical data and information on biliary chemistry shows that specific bile salts, as well as the common bile pigment bilirubin and its glucuronides plus the minor components of bile such as vitamins A, D, E, K, as well as melatonin (N-acetyl-5-methoxytryptamine) are salutary in improving liver function, dissolving gallstones, inhibiting bacterial and viral multiplication, promoting cardiac chronotropsim, as well as exhibiting anti-inflammatory, anti-pyretic, anti-oxidant, sedative, anti-convulsive, anti-allergic, anti-congestive, anti-diabe

关键词： Bile acids Bile pigments Bilirubinates Liquid crystals Materia medica Mixed micelles Bear bile Ox gallstones Paleo-pharmacology Phospholipids

FRAcTURE MEcHANISM AND MIcROMEcHANIcAL ANALYSIS OF POLYSYNTHETIcALLY TWINNED cRYSTALS OF γTiAl ALLOYS

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中国有色金属学会会刊:英文版 1999年第S1期9卷 130-137页

作者： Y.g.Zhang Y.H.Lu g.K.Hu c.q.chen Department of Materials Science and Engineering Beijing University of Aeronautics and Astronautics UnversityBeijing 100083China Department of Applied Mechanics Beijing Institute of TechnologyBeijing 100081China

The fracture behavior and mechanism of PST crystals of a Ti 49%(mole fraction)Al alloy have been studied by using in situ straining and micromechanical calculation. The three dimensional micromechanical model representing the structure of PST crystal has been built, and the stress distribution ahead of the sharp and blunt crack tips either parallel to lamellar interface or perpendicular to the lamellae has been calculated by using finite element method based on linear elasticity of PST crystals. The experimental results show that the fracture behaviors and mechanisms are strongly dependent on the angle of loading axis to the lamellae. The calculation indicates that nucleation and propagation of microcrack along the interfaces are controlled by the normal stress and translamellar microcrack is controlled by shear stress ahead of crack tip.

关键词： TiAl alloy PST crystal fracture behavior mechanism micromechanical model finite element method

Precipitation on stacking faults in Mg–9.8wt%Sn alloy

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Journal of Materials Science & Technology 2020年第10期42卷 230-240页

作者： c.q.Liu c.He H.W.chen J.F.Nie International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing400044China Department of Materials Science and Engineering Monash UniversityVictoria3800Australia Electron Microscopy center Chongqing UniversityChongqing400044PR China

In this work,we have systematically investigated precipitation ofβ’-Mg3Sn phase on intrinsic stacking faults I1 and I2 in a Mg-9.8 wt%Sn alloy using aberration-corrected scanning transmission electron *** observed I1 faults are generated by the dissociation of c+a perfect dislocations and bounded by Frank partial dislocations having a Shockley *** ofβ’on I1 involves a shear of 1/3α,similar to its formation directly from theα-Mg ***β’phase often nucleates at one end of an I1 fault due to the interaction between shear strain fields ofβ’and the Shockley component of the Frank partial at that end,and subsequently grows towards the other end of the *** theβ’reaches to the other end,the Shockley partial bounding the lengthening end of theβ’reacts with the Frank partial bounding the fault,generating an a perfect dislocation that can glide away from the precipitate and the *** observed I2 faults are generated by the dissociation of a perfect dislocations and bounded by Shockley *** ofβ’on I2 does not need a shear of 1/3α,since the pre-existing I2 fault already provides an ABcA four-layer structure ofβ’.Thickening of theβ’that has already formed on the I2 involves the successive occurrence of three crystallographically equivalent shears of 1/3αon every second(0002)αplane of theα-Mg *** this thickening mechanism is similar to that of theβ’formed directly from theα-Mg matrix,an a perfect dislocation will be produced when theβ’is thickened to eight layers,and it can again glide away from the precipitate and the fault.

关键词： Heterogeneous precipitation HAADF-STEM Shockley partial dislocation Frank partial dislocation Dislocation reaction

Influence of Fe Addition on Products of Self-Propagating High-Temperature Synthesis Reaction in 3Ti-Si-2c System

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稀有金属材料与工程 2009年第A3期38卷 113-118页

作者： guan q L Wang H Y Li S L Si W P Jiang q c Key Laboratory of Automobile Materials of Ministry of Education Jilin University Changchun 130025 China

Influence of Fe addition on products of self-propagating high-temperature synthesis (SHS) reaction in 3Ti-Si-2c system was investigated in the present study. Without Fe addition, Ti5Si3 and Tic are the dominant phases along with a small amount of Ti3Sic2 phase and unreacted c left in the final products. As Fe content ranges from 10% to 30%, the products consist of Tic, Ti5Si3, Fe2Ti and unreacted c, but no trace of Ti3Sic2 phase is detected. Furthermore, the amounts of both Fe2Ti and c phases increase with Fe content increasing. Addition of Fe has a great effect on the reaction route and significantly restrains the formation of Ti3Sic2 during the combustion synthesis process, and therefore, the SHS is not an effective fabrication technique to synthesize the ternary Ti3Sic2 ceramic in either 3Ti-Si-2c or Fe-3Ti-Si-2c system. Besides, without Fe addition, Ti5Si3 presents as the coarse irregular appearance with an obviously sintered morphology. In contrast, the shape of Ti5Si3 exhibits more and more spherical (cobblestone-like) and the surface becomes increasingly smooth, because the amount of liquids formed during the SHS reaction increases with the increase of Fe content. On the other hand, with Fe content increasing from 0 to 30 wt.%, the particulate size of Tic decreases from more than 5 μm to 1 μm or less, mainly due to the fact that the combustion temperature decreases with the increase of Fe content in the preforms.

关键词：复合材料铁含量燃烧过程物理性能

Experimental and numerical study of the effect of pulsatile flow on wall displacement oscillation in a flexible lateral aneurysm model

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Acta Mechanica Sinica 2019年第5期35卷 1120-1129页

作者： L.Z.Mu X.Y.Li q.Z.chi S.q.Yang P.D.Zhang c.J.Ji Y.He g.gao School of Energy and Power Engineering Dalian University of TechnologyDalian 116024China School of Biomedical Engineering Capital Medical UniversityBeijing 100069China The First Affiliated Hospital of University of Science and Technology of china Hefei 230036China

This study experimentally and numerically investigated the effect of pulsatile flow of different frequencies and outflow resistance on wall deformation in a lateral aneurysm.A method for constructing a flexible aneurysm model was developed,and a self-designed piston pump was used to provide the pulsatile flow conditions.A fluid-structure interaction simulation was applied for comparison with and analysis of experimental *** maximum wall displacement oscillation increased as the pulsation frequency and outflow resistance increased,especially at the aneurysm *** is an obvious circular motion of the vortex center accompanying the periodic inflow fluctuation,and the pressure at the aneurysm dome at peak flow increased as the pulsatile flow frequency and terminal flow resistance *** results could explain why abnormal blood flow with high frequency and high outflow resistance is one of the risk factors for aneurysm rupture.

关键词： Lateral aneurysm In vitro experiment Pulsatile flow Wall displacement oscillation Fluid-structure interaction simulation