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ON SIm.LTANEOUS WEAKLY-Ch.BYSh.V SUBSPACES

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Analysis in Th.ory and Applications 2011年第2期27卷 117-124页

作者： Sh. Rezapour h. Alizadeh.S. m. Vaezpour Azarbaidjan University of Tarbiat m.allem Aazad Islam.c University Am.rkabir University of Tech.ology

In th.s paper, we sh.ll introduce and ch.racterize sim.ltaneous quasi-Ch.bysh.v （and weakly-Ch.bysh.v） subspaces of norm.d spaces with.respect to a bounded set S by using elem.nts of th. dual space.

关键词： dual space best sim.ltaneous approxim.tion sim.ltaneous quasi-Ch.bysh.vsubspace sim.ltaneous weakly-Ch.bysh.v subspace

Inverse h.at Transfer Problem.of Th.rm.l Contact Conductance Estim.tion in Periodically Contacting Surfaces

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Journal of Th.rm.l Science 2009年第2期18卷 150-159页

作者： m.h.Sh.jaeefard K.Goudarzi m.Sh.m.zidi Dept. of m.ch.nical Engineering Iran University of Science and Technology

Th. problem. involving periodic contacting surfaces h.ve different practical applications. An inverse h.at conductionproblem.for estim.ting th. periodic Th.rm.l Contact Conductance (TCC) between one-dim.nsional, constantproperty contacting solids h.s been investigated with.conjugate gradient m.th.d (CGm. of function *** m.th.d converges very rapidly and is not so sensitive to th. m.asurem.nt errors. Th. advantage of th.present m.th.d is th.t no a priori inform.tion is needed on th. variation of th. unknown quantities, since th. solutionautom.tically determ.nes th. functional form.over th. specified dom.in. A sim.le, straigh. forward tech.iqueis utilized to solve th. direct, sensitivity and adjoint problem., in order to overcom. th. difficulties associatedwith.num.rical m.th.ds. Two general classes of results, th. results obtained by applying inexact sim.latedm.asured data and th. results obtained by using data taken from.an actual experim.nt are presented. In addition,extrapolation m.th.d is applied to obtain actual results. Generally, th. present m.th.d effectively im.roves th.exact TCC wh.n exact and inexact sim.lated m.asurem.nts input to th. analysis. Furth.rm.re, th. results obtainedwith.CGm.and th. extrapolation results are in agreem.nt and th. little deviations can be negligible.

关键词：热接触逆问题共轭梯度周期性

Sorption of certain lanth.nides by kieselguh. loaded with.Cyanex 572 from.sulfate m.dium

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Journal of Rare Earth. 2020年第3期38卷 299-305页

作者： Sh.Sh.Em.m.m.S.Gasser N.E.El-h.fny W.h.m.h.0}ud h.F.Aly h.t Laboratories Centre Atomic Energy AuthorityCairo 13759Egypt Departm.nt of Ch.m.stry Faculty of ScienceAin Shams UniversityCairoEgypt

Kieselguh. for ch.om.tograph. was loaded with.Cyanex 572 extractant and ch.racterized using X-ray diffraction(XRF),scanning electron m.croscopy(SEm.,Fourier transform.infra-red(FT-IR),and th.rm.l *** of som. h.avy lanth.nides togeth.r with.yttrium.by th. prepared kieselguh./Cy-572 sorbent was investigated by batch.experim.nt in term. of initial m.tal ions concentrations,volum. to solid m.ss ratio(V/m.,sulfuric acid concentration as well as *** sorption equilibrium.of Cy-572 loaded kieselguh. was satisfactorily explained by th. pseudo second-order kinetic m.del and Langm.ir isoth.rm.***,th. values of th.rm.dynam.c param.ters △G°,△h.,and △S°at25℃of th. studied m.tal ions sh.w th.t th. process is spontaneous and endoth.rm.c in nature.2.0 m.l/L h.O3 is prom.sing to desorb th.se m.tal ions.

关键词： Sorption Cyanex 572 Lanth.nides Kieselguh. Sulfate m.dium Rare earth.

Natural Convection of a Power-Law Nanofluid in a Square Cavity with.a Vertical Fin

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Fluid Dynam.cs & m.terials Processing 2024年第9期20卷 2091-2108页

作者： Am.ra m.h.dbi m.h.m.ed El Ganaoui h.ïkel Ben h.m.d Am.nallah.Guizani Kh.lid Ch.aibi LERm.B Department of Transition and Energy Efficiency ProfessionsIUT H Poincaréde LongwyUniversity of LorraineLongwy54400France LPT Center for Energy Research and Technologies(Borj Cedria2084)University of Tunis El ManarTunis1068Tunisia LTI Department of Mechanical Engineering and ProductionIUTUniversity of Picardie Jules-VerneAmiens80025France

Th. beh.vior of non-Newtonian power-law nanofluids under free convection h.at transfer conditions in a cooled square enclosure equipped with.a h.ated fin is investigated *** particular,th. im.act of nanofluids,com.osed of water and Al_(2)O_(3),TiO_(2),and Cu nanoparticles,on h.at transfer enh.ncem.nt is *** aim.of th.s research.is also to analyze th. influence of different param.ters,including th. Rayleigh.num.er(Ra=10^(4)-10^(6)),nanoparticle volum. fraction(φ=0%-20%),non-Newtonian power-law indexes(n=0.6-1.4),and fin dim.nsions(Ar=0.3,0.5,and 0.7).Stream.ines and isoth.rm. are used to depict flow and related h.at transfer *** indicate th.t th.rm.l perform.nce im.roves with.increasing Rayleigh.num.er,regardless of th. nanoparticle type or nanofluid rh.ological *** suggests th.t th. buoyancy force h.s a significant im.act on h.at transfer,particularly near th. h.at *** Nusselt num.er is m.re sensitive to variations in Cu nanoparticle volum. fractions com.ared to Al₂O₃and TiO₂.m.reover,th. average Nusselt num.ers for power-law nanofluids with.n1)are greater(sm.ller)th.n for Newtonian fluids due to th. decrease(increase)in viscosity with.increasing(decreasing)sh.ar rate,at th. sam. values of Rayleigh.num.er Ra owing to th. am.lification(attenuation)of th. convective ***,th. m.st substantial enh.ncem.nt is observed with.Cu-water sh.ar-th.nning nanofluid,wh.re th. Nusselt num.er increases by 136%wh.n ch.nging from.Newtonian to sh.ar th.nning beh.vior and by 154.9%wh.n adding 16%nanoparticle volum. ***,an even larger increase of 57%in th. average Nusselt num.er is obtained on increasing th. fin length.from.0.3 to 0.7.

关键词： h.at transfer nanofluid non-Newtonian fluid natural convection

Com.arative studies on Y(Ⅲ)and Dy(Ⅲ)extraction from.h.droch.oric and nitric acids by Cyanex 572 as a novel extractant

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Journal of Rare Earth. 2018年第12期36卷 1342-1350页

作者： N.E.El-h.fny m.S.Gasser Sh.Sh.Em.m.W.h.m.h.0}ud h.F.Aly h.t Laboratories Centre Atomic Energy Authority Faculty of Science Ain Shams University

Extraction of Y(III) and Dy(III) from.h.droch.oric and nitric acids by Cy-572 in kerosene was studied. Th. factors affecting th. extraction were separately investigated. Th. stoich.om.try of th. extracted species was deduced on th. basis of slope analysis m.th.d. Evaluation of extraction equilibrium.and stripping investigation was studied as well as saponification effect of Cy-572. Th. com.osition of th. extracted m.tal species in th. organic ph.se was found to be [m.·(h.)] for Y(III) or Dy(III) in both.m.dia.1.0 m.l/L h.I is th. best stripping agent for each.m.tal ion from.th. studied acidic m.dia in one *** Cy-572 does not exh.bit any selectivity towards th. extraction of Y(III) or Dy(III) from.both.h.I and h.Osolutions. Based on th. obtained results, th. data were com.ared and th. separation feasibility between lanth.nides and Y(III) in th. two m.dia was discussed.

关键词： Extraction Cyanex-572 Yttrium Lanth.nides Separation factor Saponification

Experim.ntal and num.rical study on plasm. nitriding of AISI P20 m.ld steel

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International Journal of m.nerals,m.tallurgy and m.terials 2016年第9期23卷 1065-1075页

作者： N.Nayebpash.ee h.Vafaeenezh.d Sh.Kh.irandish.m.Soltanieh m.terials Processing Sim.lation Laboratory(m.S-LAB) School of Materials and Metallurgical EngineeringIran University of Science and Technology(IUST) Sch.ol of m.terials and m.tallurgical Engineering Iran University of Science and Technology(IUST)

In th.s study, plasm. nitriding was used to fabricate a h.rd protective layer on AISI P20 steel, at th.ee process tem.eratures（450℃, 500℃, and 550℃） and over a range of tim. periods（2.5, 5, 7.5, and 10 h., and at a fixed gas N2：h. ratio of 75vol%：25vol%. Th. m.rph.logy of sam.les was studied using optical m.croscopy and scanning electron m.croscopy, and th. form.d ph.se of each.sam.le was determ.ned by X-ray diffraction. Th. elem.ntal depth.profile was m.asured by energy dispersive X-ray spectroscopy, wavelength.dispersive spectroscopy, and glow dispersive spectroscopy. Th. h.rdness profile of th. sam.les was identified, and th. m.croh.rdness profile from.th. surface to th. sam.le center was recorded. Th. results sh.w th.t ε-nitride is th. dom.nant species after carrying out plasm. nitriding in all strategies and th.t th. plasm. nitriding process im.roves th. h.rdness up to m.re th.n th.ee tim.s. It is found th.t as th. tim. and tem.erature of th. process increase, th. h.rdness and h.rdness depth.of th. diffusion zone considerably increase. Furth.rm.re, artificial neural networks were used to predict th. effects of operational param.ters on th. m.ch.nical properties of plastic m.ld steel. Th. plasm. tem.erature, running tim. of im.osition, and target distance to th. sam.le surface were all used as network inputs; Vickers h.rdness m.asurem.nts were given as th. output of th. m.del. Th. m.del accurately reproduced th. experim.ntal outcom.s under different operational conditions; th.refore, it can be used in th. effective sim.lation of th. plasm. nitriding process in AISI P20 steel.

关键词： tool steel plasm. nitriding sputtering neural networks

Sliding Wear Beh.vior of a Grey Cast Iron Surface Rem.lted by TIG

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Journal of m.terials Science & Tech.ology 2009年第5期25卷 622-628页

作者： h.m.h.m.dzadeh.h.Sagh.fian Sh.Kh.irandish Departm.nt of m.tallurgy and m.terials Engineering Iran University of Science and TechnologyTehranIran

Th. sliding wear beh.vior of a grey cast iron surface rem.lted by tungsten inert gas （TIG） was studied and com.ared with.th. unrem.lted one in th. current work. To evaluate th. wear beh.vior a Pin-on-Disk wear test m.ch.ne was used. Pins wh.ch.were prepared from.th. sam.les with.th. rem.lted layers of different th.cknesses of 1.2, 1.8, 2.5 and 3 turn were worn on an AISID3 steel counterface h.ving a h.rdness of 63h.C under th. applied loads of 54, 76 and gg N at a constant sliding velocity of 0.45 m.s. Scanning electron m.croscopy （SEm. equipped with.energy dispersive X-ray analysis （EDS） and X-ray diffraction （XRD） tech.iques were used to ch.racterize worn surface and subsurface and also wear debris obtained from.th. wear tests under different test conditions. Results sh.wed th.t surface rem.lted grey cast iron h.ve better wear properties for all applied norm.l loads in com.arison with.unrem.lted ones. m.croscopic studies on th. worn surfaces and subsurfaces of sam.les revealed th.t dom.nant wear m.ch.nism.for surface rem.lted sam.les was m.ld oxidative, wh.le it was severe for unrem.lted sam.les. Increasing rem.lted layer th.ckness and th.n form.ng grosser m.crostructure lead to a decline of wear properties, wh.reas lower th.ckness of rem.lted layer with.finer m.crostructure due to h.ving h.gh.r cooling rate th.ough.rem.lting process can with.tand better against wear.

关键词： Grey cast Iron Surface rem.lted Tungsten inert gas (TIG) Wear

Surveys on m.gnetosph.ric plasm.s based on th. Double Star Project (DSP) exploration

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Science Ch.na(Tech.ological Sciences) 2008年第10期51卷 1639-1647页

作者： C. P. ESCOUBET C. m. CARR h. Rm. A. FAZAKERLEY h. LAAKSO I. DANDOURAS m. DUNLOP ESA/ESTEC SCI-SH Keplerlaan 1 2200 AG Noordwijk The Netherlands Im.erial College of Science Technology and Medicine London SW7 2BZ United Kingdom CESR BP4346 31028 Toulouse Cedex 4 France m.llard Space Science Laboratory Univ. College London Dorking Surrey RH5 6NT United Kingdom Im.erial College of Science Technology and Medicine London SW7 2BZ United Kingdom Rutherford Appleton Laboratory Didcot Oxon OX11 0QX United Kingdom

Th. equatorial and polar satellites of th. Double Star Project (DSP) were launch.d successfully on Decem.er 29, 2003 and July 25, 2004, respectively, and both.of th.m.are operating sm.oth.y. Th. DSP provides a good opportunity for investigat-ing th. structure of th. m.gnetosph.re. Based on th. DSP data collected during 2004, we h.ve surveyed th. distribution of th. m.gnetic fields and plasm.s in th. m.gnetosph.re. It is found th.t: (1) Near th. Earth.s equatorial plane with.n geo-centric distances of less th.n 7 RE, th. Earth.s m.gnetic field is dipolar. In th. vi-cinity of th. m.gnetopause, th. m.gnetic field is enh.nced by a factor of about 1.5, and on th. nigh.side, th. m.gnetic field can vary significantly from.th. Earth.s di-pole field, likely caused by th. presence of th. near-Earth.tail current sh.et. (2) In th. day-side m.gnetosh.ath. th. electron and ion densities are usually both.in th. range of 10―30 cm.3; th. ion and electron tem.eratures are usually about 200 and 50 eV, respectively. Th. flow pattern is usually sm.oth. with.a low velocity in th. subsolar region and with.significantly h.gh.r velocities in th. dawn and dusk flanks. (3) In th. region between th. m.gnetopause and plasm.sph.re th. density is low, approxim.tely 0.5―5 cm.3, and th. tem.erature is h.gh. about 1―10 keV for ions and 0.1―5 keV for electrons. Th. ion tem.erature h.s an apparent anisotropy, with.th. ratio of th. perpendicular and parallel tem.eratures being about 1.0―1.3 for th. nigh.- and dusk-side m.gnetosph.re and about 1.3―2.0 for th. day- and dawn-side m.gnetosph.re. Th.re is an evident sunward convection of about 50 km.s in th. m.gnetosph.re. On th. dawn side, th. flow becom.s som.wh.t turbulent, and in th. vicinity of th. nigh.-noon m.ridian plane, th. convection is rath.r slow. (4) Th. h.gh.energy electrons with.energies h.gh.r th.n 2 m.V are m.inly located in th. regions with.3 h. size of th. h.gh.energy electrons area varies with.tim., it m.y expand and sh.ink

关键词： Earth.s m.gnetosph.re space exploration geom.gnetic field space plasm.s

Dry Sliding Oxidative Wear in Plain Carbon Dual Ph.se Steel

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Journal of Iron and Steel Research.International) 2007年第4期14卷 43-48页

作者： V Abouei h.Sagh.fian Sh.Kh.irandish Departm.nt of m.tallurgy and m.terials Engineering Iran University of Science and TechnologyNarmak 16844TehranIran

To investigate th. tribological potential of th. dual ph.se （DP） steel as a wear resistant m.terial, th. wear and th. friction ch.racteristics of th.s steel, wh.ch.consists of h.rd m.rtensite islands em.edded in a ductile ferrite m.trix, h.ve been investigated and com.ared with.th.se observed in plain carbon h.rdened （h. steel th.t h.s th. sam. carbon content of 0.2%. Dry sliding wear tests h.ve been carried out using a pin-on-disk wear testing m.ch.ne at different norm.l loads of 21.3 N, 28. 5 N, 35.7 N, and 42.6 N and at a constant sliding velocity of 1.20 m.s. Th. analysis of surface and wear debris of sam.les sh.wed th.t th. wear m.ch.nism.was m.inly m.ld oxidative. Th. friction and th. wear rate of th. h.steel and th. DP Steel h.ve been explained with.respect to th. m.crostructure and th. wear m.ch.nism.

关键词： dual ph.se steel wear m.crostructure h.at treatm.nt