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Statistical moment-based structural damage detection method in time domain

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earthquake engineering and engineering Vibration 2013年第1期12卷 13-23页

作者： j.Zhang y.L.Xu j.Li y.Xia j.C.Li Department of Civil and environmental engineering The Hong Kong Polytechnic University Department of Building engineering Tongji University Faculty.of engineering University of Technology Sydney

A novel structural damage detection method with a new damage index,i.e.,the statistical moment-based damage detection（SMBDD） method in the frequency.domain,has been recently.*** aim of this study.is to extend the SMBDD method in the frequency.domain to the time domain for building structures subjected to non-Gaussian and non-stationary.*** applicability.and effectiveness of the SMBDD method in the time domainis verified both numerically.and *** buildings with various damage scenarios are first numerically.investigated in the time domain taking into account the effect of measurement *** applicability.of the proposed method in the time domain to building structures subjected to non-Gaussian and non-stationary.excitations is then experimentally.investigated through a series of shaking table tests,in which two three-story.shear building models with four damage scenarios *** identified damage locations and severities are then compared with the preset *** comparative results are found to be satisfactory.and the SMBDD method is shown to be feasible and effective for building structures subjected to non-Gaussian and non-stationary.excitations.

关键词： damage detection statistical moment time domain non-Gaussian non-stationary experimental investigation

APPLICATION OF Hy.ROTHeRMAL TeCHNOLOGy.IN MATeRIAL Sy.THeSIS - A SeLeCTIVe ReVIeW

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化工学报 2000年第S1期51卷 307-310页

作者： Xiang L., y.n y. P., Wu H. j. and jin y. (Department of Chemical enginerring, Tsing Hua University. Beijing 100084)

This paper is a brief and selective review on hy.rothermal sy.thesis of advanced materials. Some general comments about the hy.rothermal sy.thesis of materials are presented. In particular, the surface modification and hy.rothermal sy.thesis of functional powders (e.g. the hy.rothermal coating of aluminum borate whiskers with chromium oxide, hy.rothermal sy.thesis of Ni-Zn ferrite and magnesium hy.roxide ) are introduced and their importance are explained.

关键词： Hy.rothermal technology material sy.thesis coating

Giant magnetocaloric effect in Tb_5Ge_(2-x)Si_(2-x)Mn_(2x) compounds

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Chinese Phy.ics B 2010年第5期19卷 542-548页

作者： e.y.zak B.emre y.elerman A.y.cel Department of engineering Phy.ics Faculty of EngineeringAnkara University06100 BesevlerAnkaraTurkey Faculty.of Science and Letters Physics DepartmentMugla UniversityKtekli 48000 MuglaTurkey

The cry.tal structure, magnetic and magnetocaloric characteristics of the pseduo ternary.compounds of TbsGe2-xSi2-xMn2x （0 ≤ 2x ≤ 0.1） were investigated by.x-ray.powder diffraction and magnetization measurements. The x-ray.powder diffraction results show that all compounds preserve the monoclinic phase as the majority.phase and all the sy.thesized compounds were observed to be ferromagnetic from magnetization measurements. Magnetic phase transitions were interpreted in terms of Landau theory. Maximum isothermal magnetic entropy.change value （20.84 j-kg-1 -K-1） was found for Tb5Ge1.95Si1.95Mn0.1 at around 123 K in the magnetic field change of 5T.

关键词： magnetic properties magnetocaloric effect isothermal magnetic entropy.change

INFLUeNCeS OF CASTING SPeeD AND SeN DePTH ON FLUID FLOW IN THe FUNNeL Ty.e MOLD OF A THIN SLAB CASTeR

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Acta Metallurgica Sinica(english Letters) 2007年第1期20卷 15-26页

作者： B.W. Li X.y. Tian e.G. Wang j.C. He Key.Laboratory.of National education Ministry.for electromagnetic Processing of Materials Northeastern University Shenyang 110004 China

In recent y.ars, thin slab continuous casting technology.has been widely.used to improve the quality.of the product and to reduce the cost. One of the challenges faced by.this technology.is to design reasonable flow patterns, which strongly.affect the surface and inner properties of the final slab in the mold. With the fixed scales and complex geometrical structures of nozzle and funnel ty.e mold, a series of numerical simulations are made to analy.e the flow patterns in melt steel using finite volume method based on structured body.fitted coordinate grids. The CFD （computational fluid dy.amics） package is validated first using one ty.ical case described in previously.published studies, and then it is developed to study.the effect of operational parameters on fluid flow in thin slab caster. Two operational parameters, casting speed and SeN （submerged entry.nozzle） depth, are mainly.considered for numerical analy.is. On the basis of present simulations, the reasonable SeN submergence depths corresponding to different casting speeds are suggested according to fluid flow characteristics like, flow jet impingement on the narrow side of the mold, flow speed of the melt steel beneath the meniscus and the recirculation region. This is the first stage of study.on the numerical analy.is of the whole thin slab casting process with electromagnetic brake.

关键词： continuous casting thin slab submerged entry.nozzle (SeN) numerical analy.is funnel ty.e mold standard k-ε model RNG (renormalization group) k-ε model

Microstructural softening induced adiabatic shear banding in Ti-23Nb-0.7Ta-2Zr-O gum metal

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journal of Materials Science & Technology 2020年第19期54卷 31-39页

作者： Silu Liu y.Z.Guo Z.L.Pan X.Z.Liao e.j.Lavernia y.T.Zhu Q,M,Wei y.nghao Zhao Nano and Heterogeneous Materials Center School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Department of Mechanical engineering University of North Carolina at CharlotteNC 28223-0001USA School of Aerospace Mechanical and Mechatronic EngineeringThe University of SydneyNSW 2006Australia Department of Materials Science and engineering University of Californi1IrvineCA 92697USA Department of Materials Science and engineering North Carolina State UniversityNC 27695USA

Ti-23Nb-0.7Ta-2Zr-O gum metal(GM)is an attractive candidate material for applications that require superior mechanical *** our earlier investigation of the GM[1],geometrical softening and the generation of adiabatic shear bands(ASBs)were proposed as primary.reasons for the documented anisotropic impact *** the present study.electron backscattered diffraction(eBSD)analy.is reveals two different deformed microstructures,i.e.,deformed ultrafine grains(UFGs)and dy.amically.recry.tallized UFGs,formed in the ASBs of GM samples processed by.extrusion equal channel angular pressing(eCAP),*** calculation of temperature rise during dy.amic compression suggests that the above microstructure differences in the ASBs was originated from their different maximum ASB temperatures(608 K for extruded GM and 1159 K for eCAP-processed GM).Moreover,our calculation on the temperature at the onset of ASBs indicates that microstructural softening is the primary.cause for the development of ASBs in both extruded GM(321 K)and eCAP-processed GM(331 K).

关键词： Gum metal Split hopkinson bar Adiabatic shear band Microstructures

Sperm counts and sperm sex ratio in male infertility.patients

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Asian journal of Andrology 2012年第5期14卷 683-686页

作者： Michael L eisenberg Lata Murthy.Kathleen hwang Dolores j Lamb Larry.I Lipshultz Department of Urology Stanford University School of Medicine Stanford CA 94305 USA Scott Department of Urology Baylor College of Medicine Houston TX 77030 USA Department of Urology Brown University Providence RI 02912 USA

In recent y.ars, investigators have noted a trend toward a declining proportion of male births in many.industrialized nations. While men bear the sex-determining chromosome, the role of the female partner as it pertains to fertilization or miscarriage may.also alter the gender ratio. We attempted to determine a man＇s secondary.sex ratio （F1 generation） by.directly.examining the sex chromosomes of his sperm. We examined our male infertility.clinic database for all men who had undergone a semen fluorescence in situ hy.ridization （FISH）. Patient demographic and semen parameters were recorded. Chi-squared analy.is was used to compare gender ratios （y.chromosomes/total chromosomes）. Multivariable logistic regression was used to predict the odds of possessing a y.bearing sperm after accounting for demographic and semen parameters. A total of 185 men underwent sperm FISH. For the entire cohort, the proportion of y.chromosome-bearing sperm was 51.5%. Men with less than five million motile sperm had a significantly.lower proportion of y.chromosome-bearing sperm （50.8%） compared to men with higher sperm counts （51.6%; P= 0.02）. After multivariable adjustment, a higher sperm concentration, total motile sperm count and semen volume significantly.increased the odds of having a y.chromosome-bearing sperm （P〈0.01）. As a man＇s sperm production declines, so does the proportion of y.chromosome-bearing sperm. Thus, a man＇s reproductive potential may.predict his ability.to sire male offspring.

关键词： infertility sex ratio spermatogenesis sperm chromosomes

effect of grain refinement on the hy.rogen embrittlement of 304 austenitic stainless steel

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journal of Materials Science & Technology 2019年第10期35卷 2213-2219页

作者： y.H.Fan B.Zhang j.Q.Wang e.-H.Han W.Ke Sheny.ng National Laboratory.for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and engineering University of Science and Technology of ChinaHefei 230026China CAS Key.Laboratory.of Nuclear Materials and Safety.Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The effect of grain size(in the range from 4 μm to 12 μm) on the hy.rogen embrittlement(He) of 304 austenitic stainless steel(ASS) was studied. He susceptibility.result shows that He resistance increases with grain refinement. electron backscattered diffraction kernel average misorientation(eBSD-KAM)mapping shows that the strain localization can be mitigated by.grain refinement. Hence, strain localization sites which act as highway. for hy.rogen diffusion and preferred crack initiation sites can be reduced along with grain refinement, leading to a high He resistance. Meanwhile, grain size shows no influence on the strain induced martensite(SIM) transformation during the hy.rogen charging slow strain tensile test(SSRT). Hence, the SIM formed during hy.rogen charging SSRT is not responsible for the different He resistance of 304 ASSs with various grain sizes. Hy.rogen diffusion is supposed to be controlled by.a competition between short-circuit diffusion along random grain boundary.RGB) and hy.rogen trapping at dislocations, leading to a maximum hy.rogen diffusion coefficient in the 304 ASS with an average grain size of 8 μm.

关键词： Stainless steel Grain refinement Hy.rogen embrittlement SeM eBSD

Relationship between the fatigue behavior and grain structures of an as-extruded Mg-6.2%Zn-0.6%Zr(in wt.%)alloy

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journal of Materials Science & Technology 2023年第18期149卷 119-126页

作者： B.j.Wang D.K.Xu C.L.jiang L.y.Sheng e.H.Han School of environmental and Chemical engineering Shenyang Ligong UniversityShenyang 110159China Key.Laboratory.of Nuclear Materials and Safety.Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Binzhou Institute of Technology Binzhou 256606China Shandong Key.Laboratory.of Advanced Aluminium Materials and Technology Binzhou 256606China Shenzhen Institute Shenzhen Key Lab Human Tissue Regenerate&RepairPeking UniversityShenzhen 518057China

Through investigating the tension-tension fatigue behavior of an as-extruded Mg-6.2 wt.%Zn-0.6 wt.%Zr(ZK60)alloy.it revealed that the determined fatigue strength at 107 cy.les was quite sensitive to the grain *** them,the fine grain structure had the highest fatigue strength of 130 MPa,whereas the ty.ical“bi-modal”grain structure had the lowest fatigue strength of 110 *** analy.is demon-strated that for the fine grain structure,fatigue cracks preferentially.nucleated at grain *** the“bi-modal”and coarse grain structures,the fatigue crack initiation was dominated by.the cracking along slip bands.

关键词： Mg alloy. Grain structure Cy.lic slips Fatigue behavior Crack initiation

Corrosion and passive film characteristics of 3D-printed NiTi shape memory.alloy. in artificial saliva

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Rare Metals 2023年第9期42卷 3114-3129页

作者： Ming Liu jia-Ning Zhu V.A.Popovich e.Borisov j.M.C.Mol y.Gonzalez-Garcia State Key.Laboratory.for Mechanical Behavior of Materials Center for Advancing Materials Performance from the Nanoscale(CAMP-Nano)Xi’an Jiaotong UniversityXi’an710049China Department of Materials Science and engineering Delft University of TechnologyAA Delft2600The Netherlands Peter the Great Saint-Petersburg Poly.echnic University Saint Petersburg195251Russia

electrochemical tests and surface analy.is were applied to study.the corrosion behavior and passive film characteristics of three-dimensional-printed NiTi shape memory.alloy. fabricated by.laser-powder bed fusion(LPBF) in artificial saliva at 37.C. The passivity.of L-PBF NiTi shows to be influenced by.the process parameters and resulting morphological and phy.icochemical surface properties. The results show that the defects at the surface of L-PBF Ni Ti can promote the passivation rate in the early.stages of exposure but a slowly.formed passive film shows the best corrosion protection. The thickness of the passive film is positively.correlated with its corrosion protective performance. The L-PBF NiTi alloy.prepared at a linear energy.density.of 0.2 j·m^(-1) and volumetric energy.density.of 56 j·mm^(-3) shows the least defects and best corrosion protection. An outer Ti-rich and inner Ni-rich dense passive film could be also obtained showing higher corrosion resistance.

关键词： NiTi Laser-powder bed fusion(L-PBF) Passive film Corrosion resistance Artificial saliva