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Directional solidification and physical properties measurements of the zinc-aluminum eutectic alloy

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

作者： S.Engin u.Byük H.Kaya n.Maraslι Department of Physics Institute of Science and TechnologyErciyes University Department of Science Education Faculty of EducationErciyes University Department of Physics 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-type 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 ch.nges 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 alloys directional solidification microhardness electrical conductivity enthalpy specific heat

Torsion problem for elastic multilayered finite cylinder with circular crack

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Applied Mathematics and Mech.nics(English Edition) 2017年第3期38卷 423-438页

作者： y.PROTSEROV n.VAySFELD Institute of Mathematics Economics and Mechanics Odessa Mechnikov University Dvoryanskaya str. 2 Odessa 65082 Ukraine

An axisymmetric tangent stress is applied to a lateral surface of a multilayered elastic finite cylinder with a fixed bottom face. The problem is solved for an arbitrary.number of layers. The layers are coaxial, and the conditions of an ideal mech.nical contact are fulfilled between them. A circular crack is situated parallel to the cylinder’s faces in the internal layer with branch.s free from stress. The upper face of the cylinder is also free from stress. Concretization of the problem is done on examples of two-and three-layered cylinders. An analysis of cylinders’ stress state is conducted and the stress intensity factor is evaluated depending on the crack’s geometry, its location and ratio of the shear modulus. Advantages of the proposed method include reduction of the solution constants’ number regardless of the number of layers, and presentation of the mech.nical ch.racteristics in a form of uniformly convergent series.

关键词： multilayered cylinder circular crack integral transformation singular integral equation

FORMABILITy CRITERIA OF InTERMETALLIC COMPOunDS COnTAInInG TRAnSITIOn METAL SySTEMS

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中国有色金属学会会刊：英文版 1997年第3期7卷 136-139页

作者： Guo, J Li, ch.Qin, P ch.n, ny Cao, y Qiu, GF ch.nESE ACAD SCI SHANGHAI INST METSHANGHAI 200050PEOPLES R CHINA SuZHOu unIV DEPT CHEMSUZHOU 215006PEOPLES R CHINA

ＦＯＲＭＡＢＩＬＩＴＹＣＲＩＴＥＲＩＡＯＦＩＮＴＥＲＭＥＴＡＬＬＩＣＣＯＭＰＯＵＮＤＳＣＯＮＴＡＩＮＩＮＧＴＲＡＮＳＩＴＩＯＮＭＥＴＡＬＳＹＳＴＥＭＳＧｕｏＪｉｎ，ＬｉＣｈｏｎｇｈｅ，ＱｉｎＰｅｉ，ＣｈｅｎＮｉａｎｙ... 详细信息

ＦＯＲＭＡＢＩＬＩＴＹＣＲＩＴＥＲＩＡＯＦＩＮＴＥＲＭＥＴＡＬＬＩＣＣＯＭＰＯＵＮＤＳＣＯＮＴＡＩＮＩＮＧＴＲＡＮＳＩＴＩＯＮＭＥＴＡＬＳＹＳＴＥＭＳＧｕｏＪｉｎ，ＬｉＣｈｏｎｇｈｅ，ＱｉｎＰｅｉ，ＣｈｅｎＮｉａｎｙｉＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔ...

关键词： formability criterion intermetallic compound transition element

Synthesis and Crystal Structure of Trans-bis(acesulfamato-O)tetraaquazinc(Ⅱ)

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ch.nese Journal of Structural ch.mistry 2010年第7期29卷 1047-1050页

作者： SAHIn Onur ICBuDAK Hasan B(u|¨)y.u|¨)KG(u|¨)nG(O|¨)R Orhan Department of Physics Faculty of Arts and SciencesOndokuz Mayis UniversitySamsunTurkey Department of ch.mistry Faculty of Arts and SciencesOndokuz Mayis UniversitySamsunTurkey

The title compound, trans-bis（acesulfamato-O）tetraaquazinc（Ⅱ）（I, C8H16n2O12S2Zn）, crystallizes in the triclinic system, space group P1 with a = 5.1638（5）, b = 8.5338（9）, c = 9.9583（9）A, α = 74.325（8）, β = 81.112（7）, γ = 75.800（8）°, V= 407.77（7） A3, Z = 1, F（000） = 236, Rint = 0.085, T= 296 K, the final R = 0.029 and wR = 0.078 for 1832 observed reflections with I〉 2σ（0. The ZnⅡcentre resides on a centre of symmetry and has a distorted octahedral geometry. The basal plane is defined by two carbonyl O atoms of two monodentate trans-oriented acesulfamato ligands and two trans-aqua ligands. The axial positions in the octahedron are occupied by two trans-aqua ligands. Intermolecular O-H…O hydrogen bonds produce R22（8） and R22（16） rings, which.lead to two- dimensional polymeric ch.ins.

关键词： crystal structure zinc(Ⅱ) octahedral complex hydrogen bonds

High-Speed Friction Stir Welding of T6-Treated B4Cp/6061Al Composite

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Acta Metallurgica Sinica(English Letters) 2020年第1期33卷 67-74页

作者： y.Z.Li y.n.Zan Q.Z.Wang B.L.Xiao Z.y.Ma Key Laboratory of nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China Sheny.ng national Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China university of Science and Tech.ology of ch.na Shenyang 110016China

T6-treated 20 wt% B4 Cp/6061 Al sheets were joined under welding speeds of 400–1200 mm/min by friction stir welding(FSW) with a threaded cermet pin. The macro-defect-free FSW joints could be ach.eved at high welding speeds up to 1200 mm/min, but larger plunge depth was required at the welding speeds of 800 and 1200 mm/min to eliminate the tunnel defect. In the nugget zone(nZ) of the joints, the B4 C particles were broken up and uniformly redistributed. The nZ exhibited lower hardness than the base metal(BM), and the hardness value almost did not ch.nge with increasing welding speed, attributable to the dissolution of precipitates. Compared with the BM, the joints showed lower tensile strength. As the welding speed increased from 400 to 800 mm/min, the joint efficiencies were nearly the same and up to ~ 73%. When the welding speed increased up to 1200 mm/min, the tensile strength significantly decreased, due to the occurrence of kissing bond defect at the bottom of the nZ. With increasing welding speed, the fracture location of the joints transferred gradually from the heat-affected zone to the nZ due to the kissing bond defects.

关键词： Metal-matrix composites Microstructures Mech.nical properties Friction stir welding High-speed welding

RATIOnAL GEnERAL SOLuTIOnS OF HIGHER ORDER ALGEBRAIC ODES

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Journal of Systems Science & Complexity 2013年第2期26卷 261-280页

作者： HuAnG y.nli nG L X ch.u WInKLER Franz Sch.ol of Computer Science and Software Engineering Tianjin Polytechnic University Research.Institute for Symbolic Computation(RISC) Johannes Kepler University Department of Mathematics Quy Nhon University

This paper generalizes the method of ng6 and Winkler （2010, 2011） for finding rational general solutions of a first order non-autonomous algebraic ordinary differential equation （AODE） to the case of a higher order AODE, provided a proper parametrization of its solution hypersurface. The authors reduce the problem of finding the rational general solution of a higher order AODE to finding the rational general solution of an associated system. The rational general solutions of the original AODE and its associated system are in computable 1-1 correspondence. The authors give necessary and sufficient conditions for the associated system to have a rational solution based on proper reparametrization of invariant algebraic space curves. The authors also relate invariant space curves to first integrals and ch.racterize rationally solvable systems by rational first integrals.

关键词： Algebraic ODE associated system invariant algebraic space curve rational first integral rational general solution.

ch.racteristics of urban ozone level in Hong kong

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Journal of Environmental Sciences 2001年第1期13卷 1-7页

作者： D.y.C.LEunG D.n.ZHAnG Department of Mech.nical Engineering The University of Hong KongPokfulam RoadHong KongChina Research.Institute of Environmental Engineering East China University of Science and TechnologyShanghai 200237China

The long term trend of ozone level in Hong Kong has been investigated. One of the ch.racteristics of ozone level in Hong Kong is the existence of autumn maximum and summer minimum. Observations of the diurnal variation of ozone level have been made in different area categories. There are early morning peak and afternoon peak occurred in the diurnal variation, which.are different from some metropolitans where only an afternoon peak is observed. A negative correlation coefficient was found between monthly ozone level with nitric oxide level. On the contrary, there is a positive correlation between ozone and nitrogen dioxide. The positive correlation coefficient between nitric oxide and nitrogen dioxide shows that the total amount of nitric oxide emitted from a series of moving and fixed sources greatly exceeded the stoich.ometric amount of ozone formed from ch.mical reactions of precursors and long distance transportation.

关键词： ozone urban air pollution Hong kong ch.na

Parameterization of the Absorption of the H_(2)O Continuum,CO_(2),O_(2),and Other Trace Gases in the Fu-Liou Solar Radiation Program

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Advances in Atmospheric Sciences 2005年第4期22卷 545-558页

作者：张凤曾庆存 y.Gu K.n.LIOu InstituteofAtmosphericPhysics ChineseAcademyofSciencesBeijing100029 DepartmentofAtmosphericandOceanicSciences UniversityofCaliforniaLosAngelesCalifornia90095

The absorption properties of the water vapor continuum and a number of weak bands for H2O, O2, CO2, CO, n2O, ch., and O3 in the solar spectrum are incorporated into the Fu-Liou radiation parameterization program by.using the correlated k-distribution method (CKD) for the sorting of absorption lines. The overlap absorption of the H2O lines and the H2O continuum (2500-14500 cm-1) are treated by taking the two gases as a single-mixture gas in transmittance calculations. Furthermore, in order to optimize the computation efforts, CO2 and ch. in the spectral region 2850-5250 cm-1 are taken as a new single-mixture gas as well. For overlap involving other absorption lines in the Fu-Liou spectral bands, the authors adopt the multiplication rule for transmittance computations under which.the absorption spectra for two gases are assumed to be uncorrelated. Compared to the line-by-line (LBL) computation, it is shown that the errors in fluxes introduced by these two approach.s within the context of the CKD method are small and less than 0.48% for the H2O line and continuum in the 2500-14500 cm-1 solar spectral region, -1% for H2O (line)+H2O (continuum)+CO2+ch. in the spectral region 2850-5250 cm-1, and -1.5% for H2O (line)+H2O (continuum)+O2 in the 7700-14500 cm-1 spectral region. Analysis also demonstrates that the multiplication rule over a spectral interval as wide as 6800 cm-1 can produce acceptable errors with a maximum percentage value of about 2% in reference to the LBL calculation. Addition of the preceding gases increases the absorption of solar radiation under all sky conditions. For clear sky, the increase in instantaneous solar absorption is about 9%-13% (~12 W m^2) among which.the H2O continuum produces the largest increase, while the contributions from O2 and CO2 rank second and third, respectively. In cloudy sky, the addition of absorption amounts to about 6-9 W m-2. The new, improved program with the incorporation of the preceding gases produces a smaller solar a

关键词： non-gray gas absorption correlated k-distribution method Fu-Liou code

Oxidation behavior and microstructural evolution of FeConiTiCu five-element high-entropy alloy.nanoparticles

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Journal of Materials Science & Tech.ology 2024年第10期177卷 133-141页

作者： H.Bai R.Su R.Z.Zhao C.L.Hu L.Z.Ji y.J.Liao y.n.Zhang y.X.Li X.F.Zhang Key Laboratory for Anisotropy and Texture of Materials(MOE) School of Materials Science and EngineeringNortheastern UniversityShenyang110819China Institute of Advanced Magnetic Materials College of Materials and Environmental EngineeringHangzhou Dianzi UniversityHangzhou310012China

High-entropy alloys(HEAs)have attracted extensive attention ascribed to their unique physical and ch.mical properties induced by the cocktail ***,their oxidation behaviors,in particular at nanoscale,are still lack because of multi-element complexity,which.could also be completely differ-ent from the bulk *** this work,we synthesized FeConiTiCu five-element HEA nanopar-ticles(nPs)with uniform elemental distribution by arc-disch.rging approach.and further investigated their oxidation behaviors at 250 ℃,and 350 ℃.The morphology,structure and element distribution of nPs were analyzed by transmission electron microscopy(TEM),energy dispersive spectroscopy(EDS)and electron energy loss spectroscopy(EELS).The surface oxidation in FeConiTiCu nPs during the high-temperature process can induce nanoscale pores at core/shell interfaces by Kirkendall effect,and even the eventual coalescence into a single ***,the oxidation states of nPs with diameters(d)vary.ng from 60 to 350 nm were analyzed in detail,revealing two typical configurations:hollow(dnm)and yolk-shell structures(d>150 nm).The experimental results were complemented by first-principles calculations to investigate the diffusion behaviors of five elements,evidencing that the surface oxidation strongly alters the surface segregation preferences:(1)in the initial stage,Cu and ni appear to prefer segregating on the surface,while Co,Ti and Fe tend to stay in the bulk;(2)in the oxidation process,Cu prefers to stay in the center,while Ti segregates to the surface ascribed to the reduced po-tential *** study gives new insights into oxidation of nanoscale HEA,and also provides a way for fabrication of high-entropy oxides with controllable arch.tectures.

关键词： High-entropy alloy nanoparticles Oxidation Kirkendall effect Exch.nge bias effect