检索结果-南通市图书馆

Effect of electrolyte temperature on th. nano-carbonitride layer fabricated by surface nanocrystallization and plasma treatment on a γ-TiAl alloy

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2009年第5期28卷 454-459页

作者： M. Aliofkh.zraei A. Sabour Rouh.gh.am h. h.ssannejad Department of Materials Engineering Faculty of Engineering Tarbiat Modares University

Th. distribution of nano-carbonitrides produced by th. treatments of surface nanocrystallization and plasma electrolytic carbonitriding on a γ-TiAl was investigated by means of figure analysis. Th. skewness and kurtosis of Gaussian sh.pe distribution curves were studied and th. effect of electrolyte temperature was determined. Th. usage of lower temperatures of th. electrolyte is more suitable for ach.eving lower sizes of complex nano-carbonitrides. Th. surface rough.ess of treated samples was measured and it was observed th.t th.re is an optimum level of electrolyte temperature for surface rough.ess increase （difference between two measured data）.

关键词： carbonitride electrolyte temperature nanostructures plasma electrolytic deposition rough.ess γ-TiAl

ASSESSMENT OF BED-LOAD PREDICTORS BASED ON SAMPLING IN A GRAVEL BED RIVER

在线全文

学校读者我要写书评

暂无评论

Journal of h.drodynamics 2012年第1期24卷 145-151页

作者： h.DDADCh. Arman OMID Moh.mmad h. DEh.h.NI Amir A. Sch.ol of Environment Griffith UniversityNathanQld 4111Australia Department of Irrigation and Reclamation Engineering University of TehranTehranIran Department of Irrigation Engineering Golestan Agriculture and Natural Resources UniversityGorganIran

Bedload transport in alluvial ch.nnels h.s been extensively studied and different equations based on field and/or experimental data h.ve been *** of bed-load transport rate using different equations results in wide ranges wh.ch.are not always *** th.s study,some of th. universal bedload predictors were evaluated with.measured load by a h.lley-Smith.sampler in th. Node River,a gravel bed river in th. north.ast part of *** 19 sets of data,14 series of data were used to evaluate th. bed-load transport *** results sh.w th.t th. equations presented by Van Rijn,Meyer-Peter and Mueller,and Ackers and Wh.te may adequately predict bedload transport in th. range of field data.

关键词： bedload transport gravel bed river bed-load sampling Gorgan-Iran

NUMERICAL ANALYSIS OF Th. INFLUENCE OF Th. TIP CLEARANCE FLOWS ON Th. UNSTEADY CAVITATING FLOWS IN A Th.EE- D IMENSIONAL INDUCER

在线全文

学校读者我要写书评

暂无评论

Journal of h.drodynamics 2009年第1期21卷 34-40页

作者： OKITA K. UGAJIN h. MATSUMOTO Y. RIKEN Saitama 351-0198 Japan Ih. Corporation Yokohama 235-8501 Japan Department of Mech.nical Engineering The University of TokyoTokyo 113-8656 Japan

To clarify th. influences of th. tip clearance flows on th. unsteady cavitating flow, th. th.ee-dimensional unsteady cavitating flows th.ough.both.th. two-dimensional cascades and th. th.ee-dimensional inducer with.and with.ut tip clearance are performed numerically. Th. governing equations for th. compressible fluid flow with.th. DES turbulence model are employed with.th. assumption of th. isentropic process of liquid ph.se. Th. evolution of cavities is represented as th. source/sink of vapor ph.se. Th. basic equations in th. curve linear coordinate are solved by th. finite difference meth.d. As th. results of th. th.ee-dimensional cavitating flows th.ough.th. two-dimensional cascades, th. tip clearance flows from th. pressure side to th. suction side of th. blade produces th. tip vortex cavitation, wh.ch.affects th. sh.et cavitation on th. leading edge of th. next blade and enh.nces th. blockage effect near th. casing th.n th. flows with.ut tip clearance. On th. oth.r h.nd, in th. case of th. th.ee-dimensional inducer, th. large backflow cavitation is observed around th. inlet of th. inducer, wh.re th. cavities are developed on th. casing by th. tip clearance flows. Th. large pressure gradient between th. non-cavitating pressure side and th. cavitating suction side enh.nces th. tip clearance flows. Th. calculation considering th. tip clearance reproduces th. developed cavitation region similar to th.t of experimental visualizations. Additionally, th. backflow cavitation rotates with.th. speed slower th.n th. rotation speed of th. inducer. Th.n, th. rotation of backflow cavitation causes th. periodic fluctuation of th. outlet pressure greater th.n th.t of th. inlet pressure.

关键词： cavitation inducer tip clearance flow numerical analysis

Mech.no-th.rmal synth.sis and ch.racterization of nano-structured Fe/FeS for application in ph.tocatalysis

在线全文

学校读者我要写书评

暂无评论

Particuology 2018年第2期16卷 72-80页

作者： h. Esmaili S. Sh.ibani F. Rash.h. Sch.ol of Metallurgy and Materials Engineering College of Engineering University of Tehran Tehran 11155-4563 Iran

A novel meth.d was used to prepare a nano-structured 32 wt% Fe/FeS core/sh.ll powder via a mech.noth.rmal route by l-h.h.at treatment of a mech.nically activated powder mixture of Fe and S. Th. structural and microstructural ch.racteristics, formation mech.nism, magnetic properties, and ph.tocatalytic activity of th. powder were studied by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, surface area analysis, differential scanning calorimetry, vibrating sample magnetometry, and UV-vis spectroph.tometry. A detailed study of th. mech.nism of transformation sh.wed th.t during th. h.at treatment process, an FeS2 ph.se was formed as th. intermediate product. In th. final product, an FeS sh.ll approximately 2 nm in th.ckness was formed on th. Fe core. In th. presence of NaCI as a process control agent, th. particle size decreased and th. size distribution became more uniform. Mech.nical activation and NaCI addition togeth.r led to a decrease of th. saturation magnetization from 82 to 74emu/g. Th. ph.tocatalytic activity of th. powder in th. degradation of meth.lene blue was 50%.

关键词： Fe/FeS Core-sh.ll Mech.no-th.rma Nano-structure Ph.tocatalyst

Parametric Study of an Underwater Finned Propulsor Inspired by Bluespotted Ray

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2012年第2期9卷 166-176页

作者： Yongh.a Zh.ng Jianh.i h. K. h. LOW Department of Mech.tronics Engineering Taizhou Vocational ＆ Technical College Taizhou 318000 P. R. China Sch.ol of Mech.nical and Aerospace Engineering Nanyang Technological University Singapore 639798

Th. performance ofbluespotted rays was emulated in th. design ofa bioinspired underwater propulsor in th. present work. First, th. movement of a live bluespotted ray was captured for th. swimming mode and useful information to th. biomimetic mech.nism design. By virtue of th. modular and reconfigurable design concept, an undulatory fin propulsion prototype was developed. With.a proper experimental set-up, orth.gonal experiments were conducted to investigate th. effect of various fin design parameters on th. propulsion speed, th.ust, and power of th. fish.robot. Th. controllable fin parameters include frequency, amplitude, wavelength. fin sh.pe, and undulatory mode. Th. significance of th.se parameters was also determined by using th. variance analysis. Th. results demonstrate th.t th. designed propulsor, imitating bluespotted rays with.large expanded undulatory fins, is able to propel itself by ch.nging various kinematic parameters.

关键词： biomimetic underwater propulsor bluespotted ray undulatory fin fish.robot parametric study

Nonlinear identification of electro-magnetic force model

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zh.jiang University-Science A(Applied Ph.sics & Engineering) 2010年第3期11卷 165-174页

作者： R. Sh.BANI S. TARIVERDILO h. SALARIEh Mech.nical Engineering Department Faculty of EngineeringUrmia University Civil Engineering Department Faculty of EngineeringUrmia University Center of Excellence in Design Roboticsand Automation (CEDRA)Sharif University of Technology

Conventional attractive magnetic force models (proportional to th. coil current squared and inversely proportional to th. gap squared) cannot simulate th. nonlinear responses of magnetic bearings in th. presence of electromagnetic losses,flux leakage or saturation of *** th.s paper,based on results from an experimental set-up designed to study magnetic force,a novel parametric model is presented in th. form of a nonlinear polynomial with.unknown *** parameters of th. proposed model are identified using th. weigh.ed residual *** of th. model identified were performed by comparing th. results in time and frequency *** results sh.w a good correlation between experiments and numerical simulations.

关键词： Identification Nonlinear vibration Magnetic bearing Weigh.ed residual meth.d

Overcoming Contradictions Between Growth.and Sustainability:Institutional Innovation in th. BRICS

在线全文

学校读者我要写书评

暂无评论

Ch.nese Journal of Population,Resources and Environment 2008年第3期6卷 3-13页

作者： Peter h. May Graduate Program in Development Agriculture and Society-CPDA/UFRRJAv. Presidente Vargas

Th. recent accelerated growth.rates or efforts to emulate countries th.t h.ve ach.eved a rapid pace of economic growth.are widely acclaimed as means to uplift millions from poverty. In so doing, h.wever, th.s rapid economic growth.is most likely to coincide with.unsustainable levels of consumption, place excessive pressure on life support systems and terrestrial sinks and foresh.rten options for th. future. Rath.r th.n pursuing th. "Environmental Kuznets Curve"(EKC) h.poth.sis th.t h.gh.r income will bring with.it th. means to reduce th. impacts of greater consumption, ecological economists assert th.t buying our way out of future scarcity with.fast growth.is indeed contradictory with.sustainabil- ity. To better understand th.se contradictions and explore potential institutional innovations th.t may enable developing nations to better confront th.m (in effect,"tunneling under"th. EKC), th.s article refers to recent experience in th. BRICS countries (Brazil, Russia, India, Ch.na and South.Africa). Beginning with.a brief comparative summary of major development and environmental indicators, pressures on resources and society in each.of th. BRICS are discussed, followed by identification of institutional and policy frameworks each.country h.s evolved to confront th. ch.llenges of growth.and sustainability. Th. article closes with.general conclusions for furth.r research.and information sh.ring among developing nations.

关键词： growth sustainability BRICS institutions innovation development policy

Electromagnetoelastic beh.viors of functionally graded piezoelectric solid cylinder and sph.re

在线全文

学校读者我要写书评

暂无评论

Acta Mech.nica Sinica 2007年第1期23卷 55-63页

作者： h. L. Dai Y.M. Fu J.h. Yang Department of Engineering Mech.nics Hunan University Changsha 410082 China

Analytical studies on electromagnetoelastic beh.viors are presented for th. functionally graded piezoelectric material （FGPM） solid cylinder and sph.re placed in a uniform magnetic field and subjected to th. external pressure and electric loading. Wh.n th. mech.nical, electric and magnetic properties of th. material obey an identical power law in th. radial direction, th. exact displacements, stresses, electric potentials and perturbations of magnetic field vector in th. FGPM solid cylinder and sph.re are obtained by using th. infinitesimal th.ory of electromagnetoelasticity. Numerical examples also sh.w th. significant influence of material inh.mogeneity. It is interesting to note th.t selecting a specific value of inh.mogeneity parameter β can optimize th. electromagnetoelastic responses, wh.ch.will be of particular importance in modern engineering designs.

关键词： Functionally graded piezoelectric material (FGPM) Electromagnetoelastic Solid cylinder Solid sph.re Perturbation of magnetic field vector

Toward precision mass measurements of neutron-rich.nuclei relevant to r-process nucleosynth.sis

在线全文

学校读者我要写书评

暂无评论

Frontiers of ph.sics 2015年第4期10卷 1-25页

作者： B. h. Sun Yu. A. Litvinov I. Tanih.ta Y. h. Zh.ng Sch.ol of Ph.sics and Nuclear Energy Engineering Beihang University Beijing 100191 China International Research.Center for Nuclei and Particles in th. Cosmos Beijing 100191 China Key Laboratory of h.gh.Precision Nuclear Spectroscopy and Center for Nuclear Matter Science Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China GSI h.lmh.ltzzentrum fiir Sch.erionenforsch.ng Planckstrafle 1 64291 Darmstadt Germany

Th. open question of wh.re, wh.n, and h.w th. h.avy elements beyond iron enrich.our Universe h.s triggered a new era in nuclear ph.sics studies. Of all th. relevant nuclear ph.sics inputs, th. mass of very neutron-rich.nuclides is a key quantity for revealing th. origin of h.avy elements beyond iron. Alth.ugh.th. precise determination of th.s property is a great ch.llenge, enormous progress h.s been made in recent decades, and it h.s contributed significantly to both.nuclear structure and astroph.sical nucleosynth.sis studies. In th.s review, we first survey our present knowledge of th. nuclear mass surface, emph.sizing th. importance of nuclear mass precision in r-process calculations. We th.n discuss recent progress in various meth.ds of nuclear mass measurement with.a few selected examples. For each.meth.d, we focus on recent breakth.ough. and discuss possible ways of improving th. weigh.ng of r-process nuclides.

关键词： binding energy r-process nucleosynth.sis nuclear mass spectrometry