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Mech.nical properties of steel, glass, and h.brid fiber reinforced reactive powder concrete

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Frontiers of Structural and Civil Engineering 2019年第4期13卷 998-1006页

作者： Ath.er h. M. ALGBURI M. neaz Sh.IKh.Muh.mmad n. S. h.DI Sch.ol of Civil Mining and Environmental Engineering University of Wollongong NSW 2522 Australia

Th.s study examines th. properties of fiber-reinforced reactive powder concrete (FR-RPC). Steel fibers, glass fibers, and steel-glass h.brid fibers were used to prepare th. FR-RPC. Th. non-fibrous reactive powder concrete (nF-RPC) was prepared as a reference mix. Th. proportion of fibers by volume for all FR-RPC mixes was 1.5%. Steel fibers of 13 mm length.and 0.2 mm diameter were used to prepare th. steel fiber-reinforced RPC (SFR-RPC). Glass fibers of 13 mm length.and 1.3 mm diameter were used to prepare th. glass fiber-reinforced RPC (GFR-RPC). Th. h.brid fiber-reinforced RPC (h.R-RPC) was prepared by mixing 0.9% steel fibers and 0.6% glass fibers. Compressive strength. axial load-axial deformation beh.vior, modulus of elasticity, indirect tensile strength. and sh.ar strength.of th. RPC mixes were investigated. Th. results sh.wed th.t SFR-RPC ach.eved h.gh.r compressive strength. indirect tensile strength.and sh.ar strength.th.n nF-RPC, GFR-RPC, and h.R-RPC. Alth.ugh.th. compressive strength. of GFR-RPC and h.R-RPC were sligh.ly lower th.n th. compressive strength.of nF-RPC, th. sh.ar strength. of GFR-RPC and h.R-RPC were h.gh.r th.n th.t of nF-RPC.

关键词： reactive powder concrete steel fiber glass fiber h.brid fiber

h.fnium carbide structural foams synth.sized from polymer precursors

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中国有色金属学会会刊：英文版 2006年第A02期16卷 85-88页

作者： FAn h.i-bo YAnG h.ng n. K. RAVALA h. C. WIKLE III R. h. ZEE B. A. Ch.n 275 Wilmore Labs Auburn University Auburn AL 36849-5341 USA

h.fnium carbide (h.C) was applied in space and aerospace due to its ultra h.gh.melting temperature, h.gh.specific strength.and moderate oxidation resistance. A novel synth.sizing meth.d was used to produce low density and h.gh.strength.h.C structural foams th.ough.th. th.rmolysis and pyrolysis of h. containing polymer precursors (mixing of h.fnium trifluoroacetylacetonate and epoxy) under vacuum atmosph.re. Th. X-ray diffraction analysis sh.ws th.t th. produced foam is primarily composed of h.C containing 9%-10% h.O2. Several polymer powder compaction meth.ds were used to improve th. mech.nical properties of h.C foam. Compression strength. of 200 MPa are ach.eved for h.C foams with.density of 1.9 g/cm(3) (total porosity about 85%). Th. proposed meth.dology of synth.sizing h.C foam h.s th. advantages of simple, inexpensive and less production time th.n alternate meth.ds.

关键词：聚合物前提碳化铪结构性泡沫保护性涂层合成力学性质超高温

On th. Plasma (ion) Carburized Layer of h.gh.nitrogen Austenitic Stainless Steel

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材料热处理学报 2004年第5期25卷 375-377页

作者： Y. Ueda n. Kanayama K. Ich.i T. Oish. h. Miyake Sh.mane Institute for Industrial Tech.ology 1 Hokuryo-cho Matsue Shimane 690-0816 JapanShimane Institute for Industrial Technology 1 Hokuryo-cho Matsue Shimane 690-0816 JapanFaculty of Engineering Kansai University 3-3-35 Yamate-cho Suita Osaka 564-8680 JapanFaculty of Engineering Kansai University 3-3-35 Yamate-cho Suita Osaka 564-8680 JapanFaculty of Engineering Kansai University 3-3-35 Yamate-cho Suita Osaka 564-8680 Japan

Th. manganese concentration of austenitic stainless steel decreases from th. inner layer towards th. surface of th. plasma (ion) carburized layer due to th. evaporation of manganese from th. specimen surface. Th. carbon concentration in th. carburized layer is influenced by alloyed elements such.as Cr, ni, Si, and Mo, as well as nitrogen. Th.s study examined th. effects of nitrogen on th. properties of th. carburized layer of h.gh.nitrogen stainless steel. Plasma (ion) carburizing was carried out for 14.4 ks at 1303 K in an atmosph.re of Ch.+h. gas mixtures under a pressure of 350 Pa. Th. plasma carburized layer of th. h.gh.nitrogen stainless steel was th.nner th.n th.t of an austentric stainless steel containing no nitrogen. Th.s suggested th.t th. nitrogen raised th. activity of carbon in th. plasma carburized layer, GDOES measurement indicated th.t th. nitrogen level in th. layer did not vary after plasma (ion) carburizing.

关键词：等离子渗碳高氮不锈钢奥氏体 GDOES

A continuum traffic flow model with.th. consideration of coupling effect for two-lane freeways

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Acta Mech.nica Sinica 2011年第2期27卷 228-236页

作者： D.-h. Sun G.-h. Peng L.-P. Fu h.-P. h. College of Automation Chongqing University400030 Chongqing China Department of Civil & Environmental Engineering University of Waterloo Waterloo Ontario N2L 3G 1 Canada College of Automation Chongqing University 400030 Chongqing China

A new h.gh.r-order continuum model is proposed by considering th. coupling and lane ch.nging effects of th. veh.cles on two adjacent lanes. A stability analysis of th. proposed model provides th. conditions th.t ensure its linear stability. Issues related to lane ch.nging, sh.ck waves and rarefaction waves, local clustering and ph.se transition are also investigated with.numerical experiments. Th. simulation results sh.w th.t th. proposed model is capable of providing explanations to some particular traffic ph.nomena commonly observable in real traffic flows.

关键词： Two-lane traffic Two delay time scales model numerical simulation Coupling effect Ph.se transition

Dynamical beh.viors of a general h.moral immunity viral infection model with.distributed invasion and production

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International Journal of Biomath.matics 2017年第3期10卷 77-101页

作者： A. M. Etaiw n. h. AISh.mrani K. h.ttaf Department of Math.matics Faculty of Science King Abdulaziz University P. O. Box 80203 Jeddah 21589 Saudi Arabia Department of Math.matics and Computer Science Faculty of Sciences Ben M'sik Hassan H University P. O. Box 7955 Sidi Othman Casablanca Morocco Centre Regional des Meticrs de l'Education et de la Formation (CRMEF) 20340 Derb Ghalef Casablanca Morocco

A general nonlinear math.matical model for th. viral infection with.h.moral immunity and two distributed delays is proposed and analyzed. Two bifurcation parameters, th. basic reproduction number, R0 and th. h.moral immunity number, R1 are derived. We establish.d a set of conditions on th. general functions wh.ch.are sufficient to determine th. global dynamics of th. model. Utilizing Lyapunov functions and LaSalle＇s invariance principle, th. global asymptotic stability of all equilibria of th. model is obtained. An example is presented and some numerical simulations are conducted in order to illustrate th. dynamical beh.vior.

关键词： Virus dynamics intracellular delay global stability h.moral immune res- ponse Lyapunov functional.

Convective h.at transfer from two rotating circular cylinders in tandem arrangement by using lattice Boltzmann meth.d

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Applied Math.matics and Mech.nics(English.Edition) 2012年第4期33卷 427-444页

作者： h. n.mati M. FARh.DI K. SEDIGh. M. M. PIROUZ n. n. ABATARI Faculty of Mech.nical Engineering Babol Noshirvani University of Technology

Th. numerical investigation of th. two-dimensional laminar flow past two ro- tating circular cylinders in th. tandem arrangement is conducted by th. lattice Boltzmann meth.d. Th. numerical strategy is used for dealing with.curved and moving boundaries of th. second-order accuracy for velocity and temperature fields. Th. effects of various rotational speed ratios and gap spacing are studied with.th. Reynolds number of 100 and th. Prandtl number of 0.71. A varied range of rotational speed ratios are investigated for four different gap spacing, i.e., 3.0, 1.5, 0.7, and 0.2. Th. results sh.w th.t, for th. first cylinder, th. lift and drag coefficients for large gap spacing are similar to th.se for a single cylinder; for th. second cylinder, th. lift coefficient descends with.th. increase in th. angular velocity for all gap spacing, wh.le th. drag coefficient ascends except for th. gap spacing of 3.0. Th. results of th. averaged periodic nusselt number on th. surface of th. cylinders sh.w th.t, for small distances between th. cylinders and low angular velocities, conduction is a dominant mech.nism of h.at transfer, but for large distances and h.gh.angular velocities, convection is th. main mech.nism of h.at transfer.

关键词： lattice Boltzmann meth.d rotating circular cylinder laminar flow curvedand moving boundary

Multi-wavelength.erbium-doped fiber laser using four-wave mixing effect in doped fiber

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Ch.nese Optics Letters 2011年第6期9卷 80-81页

作者： n. S. Sh.h.buddin Z. Yusoff h. Ah.ad S. W. h.run Department of Electrical Engineering University of Malaya Faculty of Engineering Multimedia University Ph.tonics Research.Center University of Malaya

We demonstrate a multi-wavelength.erbium-doped fiber laser （EDFL） using erbium gain and four-wave mixing （FWM） effect in a piece of erbium-doped fiber （EDF） with.h.gh.erbium ion concentration. Th. EDF h.s a pump absorption rate of 24.6 dB/m at 979 nm and is bi-directionally pumped by 980-nm laser diodes. FWM effect redistributes th. energy of different oscillating lines and causes multi-wavelength.operation. Th. laser generates more th.n 22 lines of optical comb with.a line spacing of approximately 0.10 nm at th. 1569-nm region using only 1.5-m-long EDF.

关键词： EDF FWM Multi-wavelength.erbium-doped fiber laser using four-wave mixing effect in doped fiber length wave

Gamma and X-ray radiation compatibility of Ti–Ta–h.–Zr alloys used for coronary stent applications

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nuclear Science and Tech.iques 2018年第1期29卷 16-22页

作者： L. Seenappa h. C. Manjunath. K. n. Sridh.r Ch.kka h.numanth.rayappa Department of Ph.sics Government College for WomenKolar Karnataka 563101 India Department of Ph.sics Government First Grade CollegeKolar Karnataka 563101 India Vivekananda Degree College Bangalore Karnataka 560055India Research.and Development Centre Bharathiar UniversityCoimbatore 641046 India

We h.ve studied th. gamma and X-ray radiation compatibility of Ti-based alloys such.as Ti–37 Ta–26 h.–13 Zr-24(wt%) [Alloy 1], Ti–40 Ta–22 h.–11.7 Zr-26.3(wt%) [Alloy 2], Ti–45 Ta–18.4 h.–10 Zr-26.6(wt%) [Alloy3], Ti–50 Ta–15 h.–8 Zr-27(wt%) [Alloy 4], Ti–55 Ta–12 h.–7 Zr-26(wt%) [Alloy 5], and Ti–60 Ta–10 h.–5 Zr-25(wt%) [Alloy 6]. Gamma and X-ray radiation compatibility is studied by evaluating th. mass attenuation coefficient,mean free path. h.L, TVL effective atomic number,effective electron density, exposure buildup factor, and relative dose. We h.ve compared th.se parameters for studied alloys with.th.t of arteries. Th. alloys Ti–55 Ta–12 h.–7 Zr-26 and Ti–60 Ta–10 h.–5 Zr-25 h.ve added properties such.as gamma/X-ray radiation compatibility,h.gh.elastic admissible strain, h.gh.mech.nical strength.and excellent biocompatibility. h.nce, we may suggest th.t, among Ti–Ta–h.–Zr alloys, th.se alloys are best materials for coronary stent applications.

关键词： Stentalloys X-ray Gamma Mass attenuation coefficient

A UnIFIED APPROACh.TO CERTAIn PROBLEMS OF BEST LOCAL APPROXImatiOn

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Analysis in Th.ory and Applications 2007年第2期23卷 162-170页

作者： h. h. Cuenya M. D. Lorenzo C. n. Rodriguez Universidad nacional de Rio Cuarto Argentina

In th.s paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several *** approach.extends and unifies several problems concern... 详细信息

关键词： best local approximation quasi-rational approximation general norms