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Contr.lling the pr.per.ies of sur.ace acoustic waves using gr.phene

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Nano r.sear.h 2016年第3期9卷 685-691页

作者： Lokeshwar.Bandhu Geoffr.y r. Nash College of Engineer.ng Mathematics and Physical Sciences University of Exeter Exeter EX4 4QF UK

Sur.ace acoustic waves （SAWs） ar. elastic waves that pr.pagate on the sur.ace of a solid, much like waves on the ocean, with SAW devices used widely in communication and sensing. The ability to dynamically contr.l the pr.per.ies of SAWs would allow the cr.ation of devices with impr.ved per.or.ance or.new functionality. However. so far.it has pr.ved extr.mely difficult to develop a pr.ctical way of achieving this contr.l. In this paper.we demonstr.te voltage contr.l of SAWs in a hybr.d gr.phene-lithium niobate device. The velocity shift of the SAWs was measur.d as the conductivity of the gr.phene was modulated using an ion-gel gate, with a 0.1% velocity shift achieved for.a bias of appr.ximately 1 V. This velocity shift is compar.ble to that pr.viously achieved in much mor. complicated hybr.d semiconductor.devices, and optimization of this appr.ach could ther.for. lead to a pr.ctical, cost-effective voltage-contr.lled velocity shifter. In addition, the piezoelectr.c fields associated with the SAW can also be used to tr.p and tr.nspor. the char.e car.ier. within the gr.phene. Uniquely to gr.phene, we show that the acoustoelectr.c cur.ent in the same device can be r.ver.ed, and switched off, using the gate voltage.

关键词： gr.phene sensor. sur.ace acoustic wave char.e tr.nspor.

Magnetic susceptibility measur.ments on metakaolin admixtur.d cement hydr.ted with gr.und water.and sea water

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Inter.ational Jour.al of Miner.ls,Metallur.y and Mater.als 2009年第3期16卷 349-354页

作者： D. Govindar.jan r. Gopalakr.shnan Depar.ment of Physics Annamalai University Annamalai Nagar608002 Tamilnadu India

The r.le of metakaolin in the pr.per.ies of Por.land cement hydr.ted with gr.und water.and sea water.was descr.bed by magnetic susceptibility study. Cement pastes containing 0wt%, 10wt%, 20wt% and 30wt% r.placement of metakaolin and in a water.cement （W/C） r.tio of 0.4 wer. pr.par.d. The susceptibility at differ.nt hydr.tion per.ods was deter.ined by Far.day Cur.e balance and it was r.lated to the changes in setting time and compr.ssive str.ngth of admixtur.d cement. Compar.d with sea water.tr.ated cement paste, the magnetic susceptibility of gr.und water.tr.ated cement paste is higher.in value. The obser.ed r.sult shows that, ir.espective of water. the magnetic susceptibility incr.ases with incr.asing metakaolin per.entage r.placement level in cement.

关键词： magnetic susceptibility admixtur.d cement hydr.tion pozzolanic activity sea water

Biomimetic Autopilot Based on Minimalistic Motion Vision for.Navigating along Cor.idor. Compr.sing U-shaped and S-shaped Tur.s

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Jour.al of Bionic Engineer.ng 2015年第1期12卷 47-60页

作者： Julien r. Ser.es Fr.nck r.ffier Aix-Mar.eille Univer.itY CNRS ISM UMR 7287 Biorobotics Lab 13288 Marseille Cedex 09 France

A bioinspir.d autopilot is pr.sented, in which body saccadic and inter.aceadic systems ar. combined. This autopilot en- ables a simulated hover.r.ft to tr.vel along cor.idor. compr.sing L-junctions, U-shaped and S-shaped tur.s, r.lying on mini- r.alistic motion vision cues alone without measur.ng its speed or.distance fr.m walls, in much the same way as flies and bees manage their.flight in similar.situations. The saccadic system r.sponsible for.avoiding fr.ntal collisions tr.gger. yawing body saccades with appr.pr.ately quantified angles based simply on a few local optic flow measur.ments, giving the angle of inci- dence with r.spect to a fr.ntal wall. The simulated r.bot negotiates stiff bends by tr.gger.ng body saccades to r.align its tr.- jector., thus tr.veling par.llel with the wall along a cor.idor.compr.sing shar. tur.s. Dir.ct compar.son shows that the per. for.ance of this new body saccade-based autopilot closely r.sembles the behavior.of a fly using similar.body saccade str.tegy when flying along a cor.idor.with an S-shaped tur., despite the huge differ.nces in ter.s of the iner.ia.

关键词： optic flow collision avoidance body saccades insect flight bior.botics biomimetics

Optimization of Manganese and Magnesium Contents in As-cast Aluminum-Zinc-Indium Alloy as Sacr.ficial Anode

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Jour.al of Mater.als Science & Technology 2011年第9期27卷 785-792页

作者： Mohammad r. Saer. Ahmad Keyvani Mater.als Engineer.ng Division Faculty of Engineering Shahrekord University

In this study, effects of manganese and magnesium content on the electr.chemical pr.per.ies of Al-Zn-ln sacr.ficial anode wer. studied in 0.5 mol/L NaCl solution （pH=5）. The aluminum base alloy with differ.nt amounts of Mn and Mg wer. melted at 750℃, then casted at molds at 25℃. Cor.osion exper.ments wer. mounted to deter.ine the optimal effect of Mn and Mg on the efficiencies of the aluminum alloy anodes. The cor.oded and unexposed sample sur.aces wer. subjected to micr.str.ctur. char.cter.zation by optical and scanning electr.n micr.scopy. AI-Zn-ln alloy doped with 0%, 0.01%, 0.05%.0.2% and 0.3% by weights of Mn and 0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5% and 3.0% by weights of Mg wer. pr.par.d to deter.ine the effect of Mn and Mg on anode efficiency in the envir.nment. The differ.nt micr.str.ctur.s of the evolved AI- Zn-ln-Mg-Mn alloy wer. cor.elated with the anode efficiencies. The Al-5.0%Zn-2.0%Mg-0.15%Mn-0.02%ln gave the best anode efficiency （about 83%）. The micr.str.ctur.s of the cor.oded sur.ace of the optimized alloy r.vealed decr.ased distr.bution of the pockets of localized attacks which ar. char.cter.stics of pitting （or.cr.vice） cor.osion.

关键词： Cor.osion Aluminum alloy Sacr.ficial anode Manganese Magnesium Cur.ent capacity

r.sponse of a slender.cylindr.cal member.under.br.aking wave impact

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Jour.al of Hydr.dynamics 2019年第2期31卷 345-357页

作者： Manjula r. Sannasir.j S.A Depar.ment of Civil Engineer.ng National Institute of TechnologyTiruchirappalliIndia Depar.ment of Ocean Engineer.ng Indian Institute of Technology MadrasChennaiIndia

A slender.cylindr.cal member.is the fundamental component of many coastal and offshor. *** is essential to under.tand the action of br.aking waves on str.ctur.l member. since,when these member. ar. subjected to wave impact load,the str.ctur.l damages and failur.s may be *** the pr.sent study,an exper.mental investigation has been car.ied out to measur. the r.sponse of the slender.ver.ical cylinder.subjected to br.aking wave *** measur.ments wer. made in or.er.to estimate the total for.e acting on the *** empir.cal r.lation is established between total impact for.e and the wave steepness par.meter.which dictates the intensity of the *** r.se time is an impor.ant par.meter.dictating the impact *** acceler.tion and str.in measur.ments wer. made to evaluate the r.sponse of the *** has been der.ved fr.m str.ctur. *** deflection due to the moder.te plunging differ. by two or.er.mor. than sever. plunging *** r.te is another.impor.ant consider.tion for.the impact *** higher.str.in r.te incr.ases the r.sistance of the *** the br.aking wave impact on the cylinder.the str.in r.te var.es fr.m 102 to 10-4.

关键词： Br.aking wave impact acceler.tion slender ver.ical cylinder wave steepness str.in r.te str.in

Investigations on pool boiling cr.tical heat flux, tr.nsient char.cter.stics and bonding str.ngth of heater.wir. with aqua based r.duced gr.phene oxide nanofluids

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Chinese Jour.al of Chemical Engineer.ng 2018年第3期26卷 445-454页

作者： r. Kamatchi G. Kumar.san School of Mechanical Engineer.ng VIT University Vellore Institute of Technology 632014 Tamil Nadu India Depar.ment of Mechanical Engineer.ng Bannar. Amman Institute of Technology Sathyamangalam 638401 Tamil Nadu India

In the pr.sent wor., the pool boiling cr.tical heat flux, tr.nsient heat tr.nsfer.char.cter.stics, and bonding str.ngth of thin Ni-Cr.wir. with aqua based r.duced gr.phene oxide(r.GO) nanofluids ar. exper.mentally studied. r.sults indicate:(i) the cr.tical heat flux(CHF) of 0.01, 0.05, 0.1, 0.2, and 0.3 g·L^(-1) concentr.tions of r.GO-water.nanofluids var.es fr.m 1.42 to 2.40 MW·m^(-2);(ii) the CHF r.mains same for.the tested samples dur.ng tr.nsient heat tr.nsfer.studies and(iii) a constant value of CHF upto 10 tests when the nanocoated Ni-Cr.wir. is tested with DI water.and deter.or.tion occur. beyond this which implies a chance of peel off of r.GO layer.below the cr.tical coating thickness.

关键词： r.duced gr.phene oxide Pool boiling Nanopar.icle deposition Tr.nsient char.cter.stics

The Consider.tion of Over.apping Lines in the Calculation of r.diative Power.Emitted fr.m CH_4 Ther.al Plasma

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Plasma Science and Technology 2012年第12期14卷 1073-1078页

作者： r. BENALLAL B. LIANI Theor.tical Physics Labor.tor. Abou Bekr Belkaid University cole pr.par.toir. des Sciences et Techniques

Net emission coefficients of r.diation wer. calculated for.isother.al plasma of methane as a function of the plasma temper.tur. 5,000 - 30,000 K and the ar. r.dius 0 mm to 10 mm at atmospher.c pr.ssur.. Calculations take into account continuum and line r.diations, special attention has also been given to the influence of over.apping spectr.l lines. The line shapes in our.calculations ar. given by convolution of Doppler.and Lor.ntz pr.files, r.sulting in a simplified Voigt pr.file. In the case of a hydr.gen pr.file, we used the Vidal tables, and the four.fir.t Lyman lines and the four.fir.t Balmer.lines wer. consider.d. This calculation was car.ied out on the assumption of local ther.odynamic equilibr.um and in a nondiffusive envir.nment. The net emission coefficient calculation for.pur. ar.on plasma was compar.d with the exper.mental r.sults of Evans in our.pr.vious wor.. We used the escape factor. and our.r.sults wer. higher.than those of the exper.ment. In this paper. we explain why, using the escape factor. the r.diation is over.stimated. The net emission coefficient obtained fr.m a r.al spectr.m was compar.d with Essoltani wor.＇s which used the line-by-line method for.pur. ar.on plasma.

关键词： ther.al plasma r.diation net emission coefficient absor.tion coefficient

On selection and scaling of gr.und motions for.analysis of seismically isolated str.ctur.s

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Ear.hquake Engineer.ng and Engineer.ng Vibr.tion 2016年第4期15卷 633-648页

作者： Deepak r. Pant Manika Mahar.an Depar.ment of Civil Engineer.ng University of Toronto Toronto ON M5S 1A4 Canada Atkins Limited The Wells Church Street Epsom KT17 4PE United Kingdom

A br.ader.consensus on the number.of gr.und motions to be used and the method of scaling to be adopted for.nonlinear.r.sponse histor. analysis （r.A） of str.ctur.s is yet to be r.ached. Ther.for., in this study, the effects of selection and scaling of gr.und motions on the r.sponse of seismically isolated str.ctur.s, which ar. r.utinely designed using nonlinear.r.A, ar. investigated. For.this pur.ose, isolation systems with a r.nge of pr.per.ies subjected to bidir.ctional excitation ar. consider.d. Benchmar. r.sponse of the isolation systems is established using lar.e sets of unscaled gr.und motions systematically categor.zed into pulse-like, non-pulse-like, and mixed set of motions. Differ.nt subsets of seven to 14 gr.und motions ar. selected fr.m these lar.e sets using （a） r.ndom selection and （b） selection based on the best match of the shape of the r.sponse spectr.m of gr.und motions to the tar.et spectr.m. Consequences of weighted scaling （also commonly r.fer.ed to as amplitude scaling or.linear.scaling） as well as spectr.l matching ar. investigated. The gr.und motion selection and scaling pr.cedur.s ar. evaluated fr.m the viewpoint of their.accur.cy, efficiency, and consistency in pr.dicting the benchmar. r.sponse. It is confir.ed that seven time histor.es ar. sufficient for.a r.liable pr.diction of isolation system displacement demands, for.all gr.und motion subsets, selection and scaling pr.cedur.s, and isolation systems consider.d. If gr.und motions ar. selected based on their.best match to the shape of the tar.et r.sponse spectr.m （which should be pr.fer.ed over.r.ndomly selected motions）, weighted scaling should be used if pulse-like motions ar. consider.d, either.of weighted scaling or.spectr.l matching can be used if non-pulse-like motions ar. consider.d, and an aver.ge of r.sponses fr.m weighted-scaled and spectr.m-matched gr.und motions should be used for.a mixed set of motions. On the other.hand, the impor.ance of r.ndomly selected motions in r.pr.sen

关键词： bidir.ctional excitation seismic isolation selection and scaling spectr.l matching weighted scaling

Effects of the plenum chamber.volume and distr.butor.geometr. on fluidized bed hydr.dynamics

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Par.icuology 2010年第1期8卷 2-12页

作者： Kiar.sh Vakhshour. John r. Gr.ce Depar.ment of Chemical and Biological Engineer.ng University of British Columbia

Most hydr.dynamic fluidized bed models, including CFD codes, neglect any effects of the plenum chamber.volume. Exper.ments wer. per.or.ed in a 0.13 m ID fluidization column to deter.ine plenum chamber.volume effects on fluidized bed hydr.dynamics for.FCC and glass par.icles. Two low-pr.ssur.-dr.p distr.butor. wer. used, one with a single or.fice, and the other.with 33 or.fices and the same total open ar.a as the single or.fice. The r.sults show two peaks in the fr.quency spectr. for.the single-or.fice distr.butor. one r.pr.senting bubble er.ption at the bed sur.ace and the other.of higher.fr.quency cor.esponding to the bubbling fr.quency at the distr.butor. The latter.decr.ased slightly with incr.asing plenum volume and with incr.asing bed depth. For.the multi-or.fice distr.butor. br.ad fr.quency spectr. fr.m pr.ssur. measur.ments became nar.ower.and moved towar.s higher.fr.quency with decr.asing plenum volume.

关键词： Fluidization Bubble Distr.butor.Plenum chamber.Hydr.dynamics Pr.ssur. dr.p