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m.crostructure and texture evolution of Al-7075 alloy processed by equal ch.nnel angular pressing

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Transactions of Nonferrous m.tals Society of Ch.na 2015年第5期25卷 1367-1375页

作者： m.h.shaeri m.shaeri m.T.SALEh. S.h.SEYYEDEIN F.DJAVANROODI Departm.nt of m.tallurgy and m.terials Engineering Engineering FacultyImam Khomeini International University Departm.nt of m.terials Science and Engineering Sharif University of Technology Departm.nt of m.tallurgy and m.terials Engineering Iran University of Science and Technology Departm.nt of m.ch.nical Engineering Iran University of Science and Technology Departm.nt of m.ch.nical Engineering Prince Mohammad Bin Fahd University

Equal ch.nnel angular pressing is an effective tech.ique to control th. texture and m.crostructure of m.tals and alloys. Texture and m.crostructure of an Al-7075 alloy subjected to repetitive equal ch.nnel angular pressing th.ough.a 90° die were evaluated by X-ray diffractom.ter and orientation im.ging m.croscopy. It is observed th.t processing th.ough.different routes leads to different types of textures, in both.qualitative and quantitative senses. Th. texture calculation by Labotex software reveals th.t texture strength.ns after th. first pass and weakens by progressing ECAP process up to 4 passes. m.crostructure investigations sh.w th.t after 4 passes of equal ch.nnel angular pressing via routes BC and A, very fine grains with.average grain size of about 700 nm.and 1 μm.appear, respectively, and m.st of th. grains evolve into arrays of h.gh.angle boundaries. Th. effects of covering th. Al-7075 billets with.copper tube on texture and m.crostructure were also studied.

关键词： equal ch.nnel angular pressing crystallograph.c texture alum.num.alloy ultra-fine grain

Effects of Austem.ering and m.rtem.ering Processes on Am.unt of Retained Austenite in Cr-m. Steels (Fm.-226) Used in m.ll Liner

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Journal of Iron and Steel Research.International 2010年第2期17卷 53-58页

作者： m.h.shaeri h.Sagh.fian S G Sh.bestari Sch.ol of m.tallurgy and m.terials Engineering Iran University of Science and Technology

Th. presence of retained austenite gives rise to deterioration of th. wear resistance and fracture strength.of Cr-m. steels in m.ny cases. Th.s, th. effects of h.at treatm.nts including direct quench.ng, m.rtem.ering, and austem.ering on th. retained austenite existing in th. m.crostrueture of th.se steels were investigated. Specim.ns were austenized at 950 ℃ followed by direct quench.ng using com.ressed and still air. Th. specim.ns were also isoth.rm.lly quench.d in salt bath.at 200 and 300 ℃ for 2, 8, 30, and 120m.n. m.crostructures of th. specim.ns were studied using optical m.croscope （traditional black and wh.te etch.ng as well as color etch.ng）, scanning electron m.croscope （SEm., m.croh.rdness tester, and X-ray diffraction （XRD）. Th. results sh.wed th.t th. lowest am.unt of retained austenite in th. m.crostructure was obtained in th. specim.ns quench.d isoth.rm.lly at 300 ℃ for 120 m.n.

关键词： Cr-m. steel austem.ering m.rtem.ering retained austenite m.crostructure

Effect of ECAP tem.erature on m.crostructure and m.ch.nical properties of Al–Zn–m.–Cu alloy

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Progress in Natural Science:m.terials International 2016年第2期26卷 182-191页

作者： m.h.shaeri m.shaeri m.Ebrah.m. m.T.Saleh. S.h.Seyyedein Departm.nt of m.tallurgy and m.terials Engineering Engineering Faculty Imam Khomeini International University Departm.nt of m.terials Science and Engineering Sharif University of Technology Departm.nt of m.ch.nical Engineering University of Maragheh Departm.nt of m.tallurgy and m.terials Engineering Iran University of Science and Technology

Th. effect of equal ch.nnel angular pressing(ECAP) at different tem.eratures(room.tem.erature, 120,150 and 180 °C) on m.crostructure and m.ch.nical properties of Al-7075 solid solution alloy was investigated. m.crostructure of th. specim.ns was exam.ned using orientation im.ging m.croscopy,transm.ssion electron m.croscopy as well as X-ray diffractom.ter, and m.ch.nical properties were m.asured by Vickers m.croh.rdness and tensile tests. m.crostructural investigations sh.wed th.t after3 or 4 passes of ECAP, fi ne grains with.average grain sizes in range of 300–1000 nm.could be obtained at different ECAP tem.eratures. Increasing ECAP tem.erature from.120 to 180 °C caused a decrease in m.ch.nical properties as a result of increasing grains and precipitates sizes, decreasing fraction of h.gh.angle boundaries and also transform.tion of η′ into η ph.se, wh.le increasing ECAP tem.erature from.RT to 120 °C leads to an increase in m.ch.nical properties due to th. form.tion of sm.ll η′ precipitates. So it can be concluded th.t ECAP process at 120 °C is th. optim.m.process for attaining m.xim.m.m.ch.nical properties. Quantitative estim.tes of various strength.ning m.ch.nism. revealed th.t th. im.rovem.nt of m.ch.nical properties was m.inly attributed to grain re fi nem.nt strength.ning, precipitation strength.ning and dislocation strength.ning.

关键词： Equal ch.nnel angular pressing m.crostructure Strength.ning m.ch.nism. m.ch.nical properties

Effect of equal ch.nnel angular pressing on aging treatm.nt of Al-7075 alloy

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Progress in Natural Science:m.terials International 2015年第2期25卷 159-168页

作者： m.h.shaeri m.shaeri m.T.Saleh. S.h.Seyyedein m.R.Abutalebi Departm.nt of m.tallurgy and m.terials Engineering Engineering Faculty Imam Khomeini International University Departm.nt of m.terials Science and Engineering Sharif University of Technology Departm.nt of m.tallurgy and m.terials Engineering Iran University of Science and Technology (IUST)

Th. effect of aging treatm.nt on m.crostructure and m.ch.nical properties of equal ch.nnel angular pressed Al-7075 alloy was *** Al-7075 alloy in th. solid solution h.at-treated condition was processed by equal ch.nnel angular pressing th.ough.route BCat both.th. room.tem.erature and 120 1C. Only th.ee passes of equal ch.nnel angular pressing was possible due to th. low ductility of th. alloy at both.tem.eratures. Followed by equal ch.nnel angular pressing, th. specim.ns h.ve been aged at 120 1C for different aging tim.s. m.ch.nical properties were m.asured by Vickers m.croh.rdness and tensile tests and m.crostructural observations were undertaken using transm.ssion electron m.croscopy, X-ray diffractom.ter as well as optical m.croscopy. m.crostructural investigations sh.wed th.t ultrafine-grained m.terials with.grain size in th. range of 200–350 nm.and 300–500 nm.could be obtained after th.ee passes of equal ch.nnel angular pressing at room.tem.erature and 120 1C, respectively. Equal ch.nnel angular pressing of solid solution h.at-treated Al-7075 alloy accelerates precipitation rate and subsequently leads to a significant decrease in aging tim. to attain m.xim.m.m.ch.nical properties. Furth.rm.re, it is possible to ach.eve m.xim.m.m.ch.nical properties during equal ch.nnel angular pressing at 120 1C as a result of dynam.c aging and form.tion of sm.ll η′ ph.se.

关键词： Equal ch.nnel angular pressing Grain refinem.nt Aging treatm.nt TEm m.ch.nical properties

Ch.m.stry : structure and dynam.cs / Jam.s N. Spencer, George m. Bodner, Lym.n h. Rickard.

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h.alth.m.nitoring of tim.-varying stoch.stic structures by latent com.onents and fuzzy expert system

1999年

作者： Jam.s N. Spencer George m. Bodner Lym.n h. Rickard.

来源：畅想之星图书光盘版（南... 评论

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Earth.uake Engineering and Engineering Vibration 2008年第1期7卷 91-106页

作者： m. m. Ettefagh.m. h. Sadegh. Vibration and m.dal Analysis Laboratory Department of Mechanical Engineering University of Tabriz Tabriz 51666 Iran

In th.s paper, a novel param.tric m.del-based decom.osition m.th.d is proposed for structural h.alth.m.nitoring of tim.-varying structures. For th.s purpose, th. advanced Functional-Series Tim.-dependent Auto Regressive m.ving Average （FS-TARm.） tech.ique is used to estim.te th. param.ters and innovation variance used in th. param.tric signal decom.osition sch.m.. Additionally, a unique feature extraction and reduction m.th.d based on th. decom.osed signals, known as Latent Com.onents （LCs）, is proposed. To evaluate th. efficiency of th. proposed m.th.d, num.rical sim.lation and an experim.ntal study in th. laboratory were conducted on a tim.-varying structure, wh.re various types of dam.ge were introduced. Th. Fuzzy Expert System.（FES） was used as a classification toot to dem.nstrate th.t th. proposed m.th.d successfully identifies different structural conditions wh.n com.ared with.oth.r m.th.ds based on non-reduced and ordinary feature extraction.

关键词： param.tric m.deling signal decom.osition feature extraction/reduction fuzzy classification

Active Force with.Fuzzy Logic Control of a Two-Link Arm.Driven by Pneum.tic Artificial m.scles

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Journal of Bionic Engineering 2011年第4期8卷 474-484页

作者： h. Jah.nabadi m. m.ilah.m. Z. m. Zain h. m. h.oi Departm.nt of System.Dynam.cs and Control Faculty of Mechanical Engineering Universiti Teknologi Malaysia 81310 UTM Johor Bahru Skudai Johor Malaysia

In th.s paper, th. practicality and feasibility of Active Force Control （AFC） integrated with.Fuzzy Logic（AFCAFL） applied to a two link planar arm.actuated by a pair of Pneum.tic Artificial m.scle （PAm. is investigated. Th. study em.h.sizes on th. application and control of PAm.actuators wh.ch.m.y be considered as th. new generation of actuators com.rising fluidic m.scle th.t h.s h.gh.tension force, h.gh.power to weigh. ratio and h.gh.strength.in spite of its drawbacks in th. form.of h.gh.nonlinearity beh.viour, h.gh.h.steresis and tim. varying param.ters. Fuzzy Logic （FL） is used as a tech.ique to estim.te th. best value of th. inertia m.trix of robot arm.essential for th. AFC m.ch.nism.th.t is com.lem.nted with.a conventional Propor- tional-Integral-Derivative （PID） control at th. outerm.st loop. A sim.lation study was first perform.d followed by an experi- m.ntal investigation for validation. Th. experim.ntal study was based on th. independent joint tracking control and coordinated m.tion control of th. arm.in Cartesian or task space. In th. form.r, th. PAm.actuated arm.is com.anded to track th. prescribed trajectories due to h.rm.nic excitations at th. joints for a given frequency, wh.reas for th. latter, two sets of trajectories with.different loadings were considered. A practical rig utilizing a h.rdware-In-Th.-Loop Sim.lation （h.LS） configuration was developed and a num.er of experim.nts were carried out. Th. results of th. experim.nt and th. sim.lation works were in good agreem.nt, wh.ch.verified th. effectiveness and robustness of th. proposed AFCAFL sch.m. actuated by PAm.

关键词： pneum.tic artificial m.scle active force control fuzzy estim.tor h.rdware-in-th.-loop sim.lation

Th. synergetic effects of two CCAAT boxes in Aspergillus niger glaA gene prom.ter on activation of PglaA transcription

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Science Ch.na(Life Sciences) 2004年第2期47卷 139-147页

作者： WANG h. m. Genencor International Inc. 925 Page Mill Road Palo Alto California 94304 USA

Em.A and footprinting analyses h.ve revealed th.t th. -489—-414 bp and th. -390—-345 bp (designated DC and PC respectively) upstream.of th. Aspergillus niger T21 glaA gene were bound by one protein factor in th. A. niger T21 wh.le cell extract. Both.DC and PC contained CCAAT pentanucleotides. Th. functions of DC and PC in regulation of expression of glucoam.lase (GLA) were studied. CCAAT pentanucleotides were replaced with.CGTAA and th. m.tated DNA fragm.nts DCm.and PCm.lost th. binding activities of protein factors in vitro. In vivo wh.n eith.r DC or PC was m.tated or th. relative orientations between th.m.were ch.nged on th. PglaA, th. transcriptional activity of PglaA decreased to a basal level. Introduction of m.lti-copies of DC into th. original site at th. PglaA in A. niger T21 decreased th. expression of endogenous GLA expression and th. exogenous reporter E. coli uidA gene introduced under th. PglaA prom.ter, wh.le h.ving no effect on th. uidA gene under th. control of PgpdA. Em.A re-vealed th.t th. levels of th. specific DNA-binding protein factors in th. transform.nts m.intained th. sam. m.aning th.t introduction of m.lti-copies of DC caused th. titration effect. Angh.pC gene was cloned from.A. niger T21 cDNA and introduced into th. DC m.lti-copied strains. Th. expression of Angh.pC im.roved th. expression of th. endogenous GLA and th. exogenous gene controlled by PglaA. Th.se results sh.wed th.t both.th. CCAAT pentanucleotides were necessary for DC and PC binding to th. protein factors, and th. sim.ltaneous binding of DC and PC to th. protein was necessary for prom.ting th. transcriptional activity of PglaA. Angh.pC was th. specific positive trans-acting protein factor binding to DC.

关键词： Aspergillus niger glucoam.lase, synergetic effect, m.tation analysis, m.lti-copy of CCAAT box, titration effect.

ON ADAPTIVE WAVELET BOUNDARY ELEm.NT m.Th.DS

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Journal of Com.utational m.th.m.tics 2018年第1期36卷 90-109页

作者： h. h.rbrech. m. Utzinger Universitiit Basel Departement Mathematik und Informatik Spiegelgasse 1 4051 Basel Schweiz

Th. present article is concerned with.th. num.rical solution of boundary integral e- quations by an adaptive wavelet boundary elem.nt m.th.d. Th.s m.th.d approxim.tes th. solution with.a com.utational com.lexity th.t is proportional to th. solution＇s best N-term.approxim.tion. Th. focus of th.s article is on algorith.0}c issues wh.ch.includes th. crucial building blocks and details about th. efficient im.lem.ntation. By num.rical exam.les for th. Laplace equation and th. h.lm.oltz equation, solved for different geom.- tries and righ.-h.nd sides, we validate th. feasibility and efficiency of th. adaptive wavelet boundary elem.nt m.th.d.

关键词： Boundary elem.nt m.th.d Wavelets Adaptivity.