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Sim.lation of inverse heat conduction problem. in fusion welding with extended analytical heat source m.dels

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Frontiers of m.terials Science 2011年第2期5卷 119-125页

作者： V. A. KARKHIN A. PITTNER c. ScHWENK m. RETHm.IER St. Petersburg State Polytechnical University St. Petersburg 195251 Russia Federal Institute for m.terials Research and Testing （BAm. Berlin Germany

The paper presents bounded volum. heat sources and the corresponding functional-analytical expressions for the tem.erature field. The power density distributions considered here are norm.l, exponential and parabolic. The sources m.del real heat sources like the welding arc, laser beam. electron beam. etc., the convection in the weld pool as well as the latent heat due to fusion and solidification. The param.ters of the heat source m.dels are unknown a priori and have to be evaluated by solving an inverse heat conduction problem. The functional-analytical technique for calculating 3D tem.erature fields in butt welding is developed. The proposed technique m.kes it possible to reduce considerably the total tim. for data input and solution. It is dem.nstrated with an exam.le of laser beam.welding of steel plates.

关键词： laser beam.welding volum. heat source functional-analytical solution inverse m.delling

Synthesis and form.tion m.chanism.of titanium.lead carbide

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Journal of Advanced ceram.cs 2018年第2期7卷 178-183页

作者： c. LING W. B. TIAN P. ZHANG W. ZHENG Y. m. ZHANG Z. m. SUN Jiangsu Key Laboratory of Advanced m.tallic m.terials School of Materials Science and Engineering Southeast University Nanjing 211189 China Jiangsu Key Laboratory of construction m.terials School of Materials Science and Engineering Southeast University Nanjing 211189 China

Ti：Pbc was synthesized for the first tim. by pressureless reaction synthesis using Ti/Pb/Tic as starting m.terials at a heating rate of 2 ℃/rain and holding at 1370 ℃ for 2 h in a tube furnace protected by Ar atm.sphere. The effects of starting powders, heating rates, and holding tem.eratures on the form.tion of Ti2Pbc were investigated. It was found that elem.ntary m.xture of Ti/Pb/c or higher heating rates fail to form.Ti2Pbc. The decreased lattice param.ters in the synthesized Ti2Pbc indicated the existence of Pb vacancies in the com.ound. A reaction m.chanism.was proposed to explain the form.tion of Ti2Pbc.

关键词： Ti2Pbc m.X phase differential scanning calorim.try (DSc) therm.l stability

ON THE RELATIONSHIP BETWEEN THE Em.EDDED-ATOm.ETHOD FUNcTION OF TITANIUm.AND TEm.ERATURE

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Acta m.tallurgica Sinica(English Letters) 1999年第2期12卷 143-148页

作者： Shen, c. Zhang, H.T. Lu, m. Bai, X.m. Zhang, Q.J. Fudan Univ Shanghai China

Tem.erature-dependent Em.edded-Atom.m.thod (EAm. functions of hcp titanium.have been determ.ned by fitting to the lattice constants and elastic constants, m.asured at various tem.eratures as well as by considering the universal Rose's relation. The EAm.functions thus obtained satisfy the stable structure requirem.nt and cauchy discrepancy. The results show that the EAm.functions do have tem.erature-dependence, and in the m.anwhile it also provides EAm.functions of titanium.for the study of Ti-based m.tallic m.terials at various tem.eratures. (Author abstract) 16 Refs.

关键词： com.uter sim.lation crystal atom.c structure Elastic m.duli Free energy m.tallic m.trix com.osites Therm.l effects

Im.ging technologies in oilfield applications

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2005年第12期6卷 1394-1400页

作者： XIE c.G. NORTH R. WILT m. ZHANG P. DENAcLARA H. LEVESQUE c. Schlum.erger cam.ridge Research Lim.ted Cambridge CB3 OEL UK Schlum.erger Beijing GeoScience center Beijing 100084 China Schlum.erger-Em. Richmond California 94804 USA Schlum.erger m.ddle East S. A. Abu Dhabi UAE

In this paper, we describe som. recent im.ging technologies developed by Schlum.erger for oilfield downhole m.l- tiphase flow production logging (PL) and cross-well electrom.gnetic (Em. survey applications. FloScan Im.ger (FSITm. has been introduced as a 3-phase oil/gas/water flow PL tool for deviated and horizontal wells. FSI sensors can m.p fluid velocity and holdup profiles along a vertical diam.ter of the wellbore at every survey depth, enabling a robust estim.te of the individual phase flow rates in com.lex flow regim.s. The cross-well Em.survey is based on cross-borehole induction logging technique and provides resistivity distribution at a reservoir scale. It is a useful tool for reservoir m.nagem.nt and is m.st effective in dynam.c fields where fluid saturations are variable in tim. and space. The tool can be used to identify (water or steam. flooded and bypassed regions. By m.nitoring changes in the resistivity spatial distribution with tim., cross-well Em.survey is very effective at m.pping inter-well tem.erature and structure. Som. field exam.les are shown for both FloScan Im.ger PL tool and cross-well resistivity im.ging survey.

关键词： Oilfield Production logging (PL) m.ltiphase flow Im.ging Tom.graphy cross-well resistivity

Variation in sexual dim.rphism.and assortative m.ting do not predict genetic divergence in the sexually dim.rphic Goodeid fish Girardinichthys m.ltiradiatus

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current Zoology 2012年第3期58卷 440-452页

作者： c. m.cIAS GARcIA G Sm.TH c. GONZALEZ ZUARTH J. A. GRAVES m. G. RITcHIE Departam.nto de Ecologia Evolutiva Instituto de Ecologia UNAM A. E 70-275 C. E 04510 M6xico DE M6xico School of Biology University of St Andrews St Andrews Fife KY16 9TH Scotland UK

Sexual dim.rphism.is often used as a proxy for the intensity of sexual selection in com.arative studies of sexual selection and diversification. The m.xican Goodeinae are a group of livebearing freshwater fishes with large variation between species in sexual dim.rphism.in body shape. Previously we found an association between variation in m.rphological sexual dim.rphism.between species and the am.unt of gene flow within populations in the Goodeinae. Here we have exam.ned if m.r- phological differentiation within a single dim.rphic species is related to assortative m.ting or gene flow between populations. In the Am.rillo fish Girardinichthys m.ltiradiatus studies have shown that exaggerated m.le fins are targets of fem.le preferences. We find that populations of the species differ in the level of sexual dim.rphism.displayed due to faster evolution of differences in m.le than fem.le m.rphology. However, this does not predict variation in assortative m.ting tests in the laboratory; in fact dif- ferences in m.le m.rphology are negatively correlated with assortative m.ting. m.crosatellite m.rkers reveal significant genetic differences between populations. However, gene flow is not predicted by either m.rphological differences or assortative m.ting. Rather, it dem.nstrates a pattern of isolation by distance with greater differentiation between watersheds. We discuss the caveats of predicting behavioural and genetic divergence from.so-called proxies of sexual selection [current Zoology 58 （3）： 440-452, 2012].

关键词： Sexual dim.rphism Assortative m.ting Genetic distance Speciation Viviparous fish

calculation of photon shielding properties for som. neutron shielding m.terials

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Nuclear Science and Techniques 2017年第5期28卷 74-80页

作者： A. m. El-Khayatt Physics Departm.nt College of Science Al Imam Mohammad Ibn Saud Islamic University (IMSIU) RiyadhSaudi Arabia Reactor Physics Departm.nt NRC Atomic Energy Authority 13759 Cairo Egypt

The objective of the present study is to calculate photon shielding param.ters for seven polyethylene-based neutron shielding m.terials. The param.ters include the effective atom.c num.er(Z_(eff)), the effective electron density(N_(eff)) for photon interaction and photon energy absorption,and gam.a-ray kerm. coefficient(kc). The calculations of Z_(eff)are presented as a single-valued and are energy dependent. While Z_(eff)values were calculated via sim.listic powerlaw m.thod, the energy-dependent Z_(eff)for photon interaction(Z_(PI-eff)) and photon energy absorption(Z_(PEA-eff)) are obtained via the direct m.thod for energy ranges of 1 keV–100 GeV and 1 keV–20 m. V, respectively. The kccoefficients are calculated by sum.ing the contributions of the m.jor partial photon interactions for energy range of 1 keV–100 m.V. In m.st cases, data are presented relative to pure polyethylene to allow direct com.arison over a range of energy. The results show that com.ination of polyethylene with other elem.nts such as lithium.and alum.num.leads to neutron shielding m.terial with m.re ability to absorb neutron and crays. Also, the kerm. coefficient first increases with Z of the additive elem.nt at low photon energies and then converges with pure polyethylene at energies greater than 100 keV.

关键词： Neutron shielding m.terials Effective atom.c num.er Kerm. coefficient c-rays

Structural behavior of interm.diate length cold-form.d steel rack colum.s with c-stitches

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Frontiers of Structural and civil Engineering 2019年第4期13卷 937-949页

作者： m. ANBARASU m.hm.d ASHRAF Departm.nt of civil Engineering Government College of Engineering Salem 636011 India School of Engineering Deakin University Geelong VIC 3216 Australia

This article presents an experim.ntal and num.rical investigation on the strength and perform.nce of interm.diate length rack colum. sections with c-stitches under axial com.ression. The test program.consisted of 10 axial concentric com.ression tests on colum.s with and without c-stitches under pin end conditions for two different geom.tric lengths. Finite elem.nt (FE) m.dels were developed using com.ercial FE package ABAQUS considering m.terial and geom.tric nonlinearities as well as initial geom.tric im.erfections. The elastic buckling properties of the section were calculated using readily available linear elastic buckling analysis tools based on Generalized Beam.Theory (GBT) and Finite Strip m.thod (FSm.. Obtained FE results were com.ared with those obtained experim.ntally, and once verified the developed FE m.deling technique was used to carry out a param.tric study to exam.ne changes in structural response due to variations in length, depth and spacing of c-stitches. Observed influences of c-stitches on the behavior and resistance of the considered colum.s were carefully analyzed, and key design aspects are presented herein.

关键词： cold-form.d steel colum.s c-stitches interm.diate length colum.s distortional buckling

Three-Body calculation of 4He（αα,γ）12c Reaction at Stellar Energies

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chinese Physics Letters 2015年第7期32卷 25-28页

作者： Firoozabadi m. m. Sadeghi H. Departm.nt of Physics University of Birjand Birjand Iran Departm.nt of Physics Faculty of Science Arak University Arak 8349-8-38156 Iran

The triple-alpha reaction is the key to our understanding about the nucleosynthesis and the observed abundance of 12c in stars. On the basis of our m.del, the triple-alpha radiative capture process is studied by using the three-body Faddeev approach as well as two- and three-body electrom.gnetic currents. The bound and resonance states of 12 c are calculated via an inverse process： three-a photodisintegration of a 12 c nucleus.

关键词： Three-Body calculation of c Reaction at Stellar Energies

Transfer of Natural m.cro Structures to Bionic Lightweight Design Proposals

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Journal of Bionic Engineering 2013年第4期10卷 469-478页

作者： m. m.ier D. Siegel K.-D. Thoben N. Niebuhr c. Ham. Alfred Wegener Institute for Polar and m.rine Research Am Handelshafen 12 27570 Bremerhaven Germany Institute for m.rine Resources Gm.H Bussestr. 27 27570 Bremerhaven Germany University of Brem.n Hoehschulring 20 28359 Bremen Germany

The abstraction of com.lex biological lightweight structure features into a producible technical com.onent is a funda- m.ntal step within the transfer of design principles from.nature to technical lightweight solutions. A m.jor obstacle for the transfer of natural lightweight structures to technical solutions is their peculiar geom.try. Since natural lightweight structures possess irregularities and often have extrem.ly com.lex form. due to elaborate growth processes, it is usually necessary to sim.lify their design principles. This step of sim.lification/abstraction has been used in different biom.m.tic m.thods, but so far, it has an arbitrary com.onent, i.e. it crucially depends on the com.etence of the person who executes the abstraction. This paper describes a new m.thod for abstraction and specialization of natural m.cro structures for technical lightweight com.o- nents. The new m.thod generates stable lightweight design principles by using topology optim.zation within a design space of preselected biological archetypes such as diatom. or radiolarian. The resulting solutions are adapted to the technical load cases and production processes, can be created in a large variety, and m.y be further optim.zed e.g. by using param.tric optim.zation.

关键词： biom.m.tic finite elem.nts design space design principle topology optim.zation param.tric optim.zation dia- tom. radiolarian