检索结果-南通市图书馆

Directional solidification and phy.ical properties measurements of the zinc-aluminum eutectic alloy

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy.and Materials 2011年第6期18卷 659-664页

作者： S.Engin U.by.k H.Kay. n.Maraslι Department of Phy.ics Institute of Science and TechnologyErciyes University Department of Science Education Faculty of EducationErciyes University Department of Phy.ics Faculty of ScienceErciyes University

Zn-5wt% Al eutectic alloy.was directionally.solidified with different growth rates （5.32-250.0μm/s） at a constant temperature gradient of 8.50 K/mm using a bridgman-ty.e growth *** values of eutectic spacing were measured from transverse sections of the *** dependences of the eutectic spacing and undercooling on growth rate are determined as λ=9.21V-0.53 and ΔT=0.0245V0.53,*** results obtained in this work were compared with the Jackson-Hunt eutectic theory.and the similar experimental results in the *** of directionally.solidified samples was also measured by.using a microhardness test *** dependency.of the microhardness on growth rate is found as Hv=***,the electrical resistivity.（r） of the casting alloy.changes from 40×10-9 to 108×10-9 Ω·m with the temperature rising in the range of 300-630 *** enthalpy.of fusion （ΔH） and specific heat （Cp） for the Zn-Al eutectic alloy.are calculated to be 113.37 J/g and 0.309 J/（g·K）,respectively.by.means of differential scanning calorimetry.（DSC） from heating trace during the transformation from liquid to solid.

关键词： eutectic alloy. directional solidification microhardness electrical conductivity.enthalpy.specific heat

High-temperature thermody.amics of silver:Semi-empirical approach

在线全文

学校读者我要写书评

暂无评论

Chinese Phy.ics b 2017年第11期26卷 400-407页

作者： R H Joshi b y.Thakore P R Vy.s A R Jani n K bhatt Department of Phy.ics Sardar Patel University Department of Phy.ics School of Sciences Gujarat University Sardar Patel Center for Science and Technology Department of Phy.ics M.K.Bhavnagar University

We report high-temperature thermody.amics for fcc silver by.comb.ning ab initio phonon dy.amics to empirical quadratic temperature-dependent term for anharmonic part of Helmholtz free energy. The electronic free energy.is added through an interpolation scheme, which connects ambient condition free electron gas model to Thomas-Fermi *** present study.shows good agreement with experimental and reported findings for several thermal properties, and the discrepancy.observed in some caloric properties is addressed. The decreases in the product of volume thermal expansion coefficient and isothermal bulk modulus and in the constant volume anharmonic lattice specific heat at high temperature are the clear evidences of proper account of anharmonicity. The present study.also reveals that T-2-dependent anharmonic free energy.is sufficient for correct evaluation of thermal pressure and conventional Grüneisen parameter. We observe that the intrinsic phonon anharmonicity.starts dominating above characteristic temperature, which is attributed to higher order anharmonicity.and can be related to higher order potential derivatives. We conclude that the uncorrelated and largeamplitude lattice vibrations at high temperature raise dominating intrinsic thermal stress mechanism, which surpasses the phonon-anharmonism and requires future consideration.

关键词： thermody.amics anharmonicity.Grüneisen parameter silver

Finite Element Analy.is of Push-Out Test of SiC Fiber Reinforced Titanium Matrix Composites

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2009年第A3期38卷 50-53页

作者： y.an M n y.ng y.Q Huang b Zhang R J School of Materials Northwestern Polytechnical University Xi＇an 710072 China

based on the interphase lay.r model and the spring lay.r model, an improved interface model was developed to evaluate the interfacial shear strength of Titanium matrix composites(TMCs) and to analy.e the effects of various parameters on the interfacial properties. The results showed that the improved interface model is more suitable for calculating the interfacial properties of SiC fiber reinforced titanium matrix composites. The interfacial shear strength of SiC/Timetal-834 predicted is 500 MPa. In addition, in order to better understand the interfacial properties of composites, some push out phenomenon were analy.ed.

关键词：复合材料剪切强度碳化硅纤维物理性能

Ground state energy.of excitons in quantum dot treated variationally.via Hy.leraas-like wavefunction

在线全文

学校读者我要写书评

暂无评论

Chinese Phy.ics b 2009年第4期18卷 1578-1585页

作者： S. Sakiroglu . Dogan A. y.ldιz K. Akgngr H. Epik y. Ergn H. Sarι . Skmen Phy.ics Department Dokuz Eyll University Phy.ics Department Anadolu University Phy.ics Department Cumhuriyet University

In this work, the effects of quantum confinement on the ground state energy.of a correlated electron-hole pair in a spherical and in a disc-like quantum dot have been investigated as a function of quantum dot size. Under parabolic confinement potential and within effective mass approximation Ritz＇s variational method is applied to Hy.leraas-like trial wavefunction. An efficient method for reducing the main effort of the calculation of terms like τekh exp （-λτeh） is introduced. The main contribution of the present work is the introduction of integral transforms which provide the calculation of expectation value of energy.and the related matrix elements to be done analy.ically.over single-particle coordinates instead of Hvlleraas coordinates.

关键词： exciton parabolic confinement variational method Hy.leraas coordinates

Microstructural characteristics and mechanical properties of the hot extruded Mg-Zn-y.nd alloy.

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第1期60卷 44-55页

作者： b.n.Du Z.y.Hu L.y.Sheng D.K.Xu y.X.Qiao b.J.Wang J.Wang y.F.Zheng T.F.Xi Shenzhen Institute Peking UniversityShenzhen 518057China Key.Laboratory.of nuclear Materials and Safety.Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Jiangsu University.of Science and Technology Zhenjiang 212003China Shenzhen y.zhan Electronics Co. LtdShenzhen 518110China

A new ty.e of Mg-Zn-y.nd alloy.for degradable orthopedic implants was *** the present study.the Zn and y.content was adjusted and their influences on the microstructures and mechanical behaviors were discussed in *** results showed that the as-extruded Mg-Zn-y.nd alloy. are mainly.composed of fine dy.amic recry.tallized grains(DRXed grains),la rge unDRXed grains and linearly.distributed secondary.*** cha nge of Zn content exerts little influence on the grain structure of the extruded Mg-Zn-y.nd alloy.while the increase of y.content would hinder the dy.amic recry.tallization process and the growth of the DRXed grains,thus the size and volume fraction of the equiaxed DRXed grains *** tensile and compressive properties are very.little affected by.Zn content because of the similar grain *** y.content increases,the tensile y.eld strength(Ty.) and ultimate strength(TUS) increase while the elongation decreases,this is caused by.a comb.ned strengthening effect of grain refinement,texture,precipitation and *** compressive y.eld strength(Cy.) and ultimate strength(CUS) of Mg-Zn-y.nd alloy.with diffe rent y.content exhibit a similar tendency.as the tensile test.

关键词： Mg-Zn-y.nd alloy Microstructure Tensile properties Compressive properties basal texture Twin

Microstructural,Mechanical,Electrical,and Thermal Properties of the bi-Sn-Ag Ternary.Eutectic Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University.of Technology.Materials Science) 2017年第1期32卷 147-154页

作者： KAy. Hasan EnGÍn Sevda AKER Ay.ur büy.K Ugur ÇADIRLI Emin Faculty.of Education Department of science EducationErciyes UniversityKayseriTurkey Faculty.of Thech Department of Energy Systems EngineeringDumluplnar Univ.KütahyaTurkey Faculty.of Education Department of Computer and instructional TechnologiesSiirt UniversitySürtTurkey Faculty.of Arts and Sciences Department of PhysicsOmer Halisdemir UniversityNigdeTurkey

The development of lead-free solders has emerged as one of the key.issues in the electronics packaging ***-Sn-Ag eutectic alloy.has been considered as one of the lead-free solder materials that can replace the toxic Pb-Sn eutectic solder without increasing soldering *** investigated the effects of temperature gradient and growth rate on the mechanical,electrical and thermal properties of the biSn-Ag ternary.eutectic ***-47 wt%Sn-0.68 wt%Ag alloy.was directionally.solidified upward with different temperature gradients（G=2.33-5.66 K/mm） at a constant growth rate（V=13.25 μm/s） and with different growth rates（V=6.55-132.83 μm/s） at a constant temperature gradient（G=2.33 K/mm） in the growth *** microstructures（λ）,microhardness（HV）,tensile stress（σ）,electrical resistivity.ρ）,and thermal properties（△H,Cp,Tm） were measured on directionally.solidified *** dependency.of the λ,HV,σ,and ρ on G and V was *** to the experimental results,X values decrease with increasing G and V,but HV,λ,and ρ values increase with increasing G and *** of electrical resistivity.ρ） for cast samples with the temperature in the range of 300-400 K were also measured by.using a standard dc four-point probe *** enthalpy.of fusion（△H） and specific heat（Cp） for the same alloy.was also determined by.means of differential scanning calorimeter（DSC） from heating trace during the transformation from eutectic liquid to eutectic solid.

关键词： solidification microhardness tensile stress electrical resistivity enthalpy

(E)-1-[4-(2-hy.roxy.5-methoxy.0}zy.ideneamino)-pheny.]ethanone and (E)-1-[4-(2-hy.roxy.4-methoxy.0}zy.ideneamino) pheny.]ethanone:X-ray.and DFT-calculated structures

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2011年第1期30卷 111-119页

作者： SAHn Onur by.KGnGR Orhan ALbAy.AK igdem ODAbASOGLU Mustafa Department of Phy.ics Faculty of Arts and SciencesOndokuz Mayls University Department of Science Education Sinop University Chemistry.Programme Pamukkale University 20159 Denizli

The isomeric structures of（E）-1-[4-（2-hy.roxy.5-methoxy.0}zy.ideneamino）-pheny.] ethanone（I） and（E）-1-[4-（2-hy.roxy.4-methoxy.0}zy.ideneamino） pheny.]ethanone（Ⅱ） ,both C16H15nO3,have been determined using X-ray.diffraction techniques and characterized by.IR,and their molecular structures have also been optimized at the b3Ly./6-31G（d,p） level using density.functional theory.DFT） . The energetic behaviors of the title compounds in solvent media have been examined using b3Ly. method with the 6-31G（d,p） basis set by.apply.ng the polarizable continuum model（PCM） . The total energies of the title compounds decrease with the increasing polarity.of the solvent. In addition,DFT calculations of the title compounds＇ molecular electrostatic potentials（MEP） were performed at the b3Ly./6-31G（d,p） level of theory. X-ray.study.shows that the title compounds both have strong intramolecular O-H…n hy.rogen b.nds. The molecules of Ⅰ are linked into a one-dimensional framework structure by.C-H…π interactions,while in Ⅱ,intermolecular π···π interactions result in the formation of infinite chains running along the [010].

关键词： cry.tal structure Schiff base DFT molecular electrostatic potential

Levitation and lateral forces between a point magnetic dipole and a superconducting sphere

在线全文

学校读者我要写书评

暂无评论

Chinese Phy.ics b 2016年第5期25卷 453-456页

作者： H M Al-Khateeb M K Alqadi F y.Alzoubi b Albiss M K Hasan (Qaseer) n y.Ay.ub Department of Phy.ics Jordan University of Science and Technology School of basic Sciences and Humanities German Jordanian University

The dipole–dipole interaction model is employ.d to investigate the angular dependence of the levitation and lateral forces acting on a small magnet in an anti-sy.metric magnet/superconducting sphere sy.tem. breaking the sy.metry.of the sy.tem enables us to study.the lateral force which is important in the stability.of the magnet above a superconducting sphere in the Meissner state. Under the assumption that the lateral displacement of the magnet is small compared to the phy.ical dimensions of our proposed sy.tem, analy.ical expressions are obtained for the levitation and lateral forces as a function of the geometrical parameters of the superconductor as well as the height, the lateral displacement, and the orientation of the magnetic moment of the magnet. The dependence of the levitation force on the height of the levitating magnet is similar to that in the sy.metric magnet/superconducting sphere sy.tem within the range of proposed lateral displacements. It is found that the levitation force is linearly.dependent on the lateral displacement whereas the lateral force is independent of this displacement. A sinusoidal variation of both forces as a function of the polar and azimuthal angles specify.ng the orientation of the magnetic moment is observed. The relationship between the stability.and the orientation of the magnetic moment is discussed for different orientations.

关键词： lateral and levitation forces Meissner effect dipole–dipole interaction model superconductor

Effect of bismuth on Intermetallic Compound Growth in Lead Free Solder/Cu Microelectronic Interconnect

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2011年第8期27卷 741-745页

作者： T.y. Kang y. y. Xiu L. Hui J.J. Wang W.P. Tong C.Z. Liu Key.Laboratory.of Electromagnetic Processing of Materials Ministry of Education Northeastern University Shenyang 110004 China Sheny.ng Aerospace University Shenyang 110136 China

The intermetallic compound （IMC） growth kinetics in pure Sn/Cu and Sn10 wt%bi/Cu solder joints was studied, respectively. after they.were aged at 160-210℃ for different time. It was found that the total IMC in Sn10 wt%bi/Cu joint developed faster than it did in pure Sn/Cu solder joint, when they.were aged at the same temperature. And the activation energy.Qa for total IMC in Sn10 wt%bi/Cu joint was lower than that for pure Sn/Cu interconnect. The IMC growth process was discussed. The IMC Cu6Sn5 was enhanced in compensation of reduced IMC Cu3Sn growth. The work reveals that bi element containing in lead free solder alloy. with 10 wt% can enhance IMC growth in lead free solder/Cu joint during service.

关键词： Solder Interfacial reaction Intermetallics Kinetics