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Reveal.ng the high-frequency attenuation mechanism of pol.urea-matrix composites

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Acta Mechanica Sinica 2020年第1期36卷 130-142页

作者： J.Cheng z.l.l.u C.C.l.o T.l. z.J.l. Y.Kang z.z.uang Appl.ed Mechanics l.boratory School of Aerospace EngineeringTsinghua UniversityBeijing100084China Key l.boratory of Advanced Material. of Ministry of Education Department of Chemical EngineeringTsinghua UniversityBeijing100084China School.of Material. Science and Engineering Tsinghua UniversityBeijing100084China

In this paper,a method for anal.z.ng the high-frequency attenuation property of pol.urea-matrix composites is devel.ped by combining experimental.computational.and theoretical.***,the ul.rasonic experimental.pl.tform is establ.shed by sol.ing the difficul.ies of high-frequency ul.rasonic testing as high-frequency signal.distortion,insufficient driving vol.age and sampl.ng rate fail.re,to study the dynamic mechanical.properties(1-5 MHz.of pure pol.urea and pol.urea-matrix ***,the infl.ences of composite parameters incl.ding the siz. and vol.me fraction of incl.sions on wave attenuation performance under different frequencies are obtained and further verified by numerical.***,the contribution of incl.sions to the wave attenuation performance is al.o theoretical.y *** is found that the increase of incl.sion vol.me fraction and incl.sion diameter wil. increase the attenuation coefficient of the *** the attenuation of composites with the incl.sions of a 150-μm diameter and 30%as vol.me fraction can be 82%higher than pure *** ampl.fying attenuation effect of incl.sions is mainl. attributed to the scattering effect,which is verified by comparing numerical.and theoretical.resul.s.

关键词： Pol.urea Viscoel.stic Dynamic mechanical.properties Ul.rasound

Probing a Dissipative Phase Transition with a Trapped Ion through Reservoir Engineering

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Chinese Physics l.tters 2022年第2期39卷 10-14页

作者： M.-l.Cai z.-D.l.u Y.Jiang Y.-K.Wu Q.-X.Mei W.-D.z.ao l.he X.z.ang z.-C.z.ou l.-M.Duan Center for Quantum Information Institute for Interdisciplinary Information SciencesTsinghua UniversityBeijing 100084China Department of Physics Renmin UniversityBeijing 100084China Beijing Academy of Quantum Information Sciences Beijing 100193China

Dissipation is often considered as a detrimental.effect in quantum systems for unitary quantum ***,it has been shown that suitabl. dissipation can be useful.resources in both quantum information and quantum ***,we propose and experimental.y simul.te a dissipative phase transition(DPT)model.using a singl. trapped ion with an engineered *** show that the ion’s spatial.oscil.ation mode reaches a steady state after the al.ernating appl.cation of unitary evol.tion under a quantum Rabi model.Hamil.onian and sideband cool.ng of the *** average phonon number of the oscil.ation mode is used as the order parameter to provide evidence for the *** work highl.ghts the suitabil.ty of trapped ions for simul.ting open quantum systems and shal. facil.tate further investigations of DPT with various dissipation terms.

关键词： quantum unitary oscil.ation

Decol.riz.tion of Direct Bl.ck 22 by Aspergil.us ficuum

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Journal.of Environmental.Sciences 2001年第4期13卷 472-475页

作者： Dong, X.-j. Du, z.-y. Chen, z. Dept. of Biol.gy/Environmental.Sci. Wenzhou Normal College Wenzhou 325003 China

The decol.riz.tion of Direct Bl.ck 22 by Aspergil.us ficuum has been studied. It was found that Aspergil.us ficuum coul. effectivel. decol.riz. Direct Bl.ck 22 especial.y when grown as pel.eted mycel.a. Resul.s showed that the media containing Direct Bl.ck 22 at 50 mg/l.coul. be decol.riz.d by 98.05% of the initial.col.r in 24 h. The optimum pH and temperature of decol.riz.tion are 4.0 and 33 °C respectivel.. Aeration was quite beneficial.to decol.riz.tion. Medium composition and the concentration of Direct Bl.ck 22 coul. affect the rate of decol.riz.tion. The dye degraded products assayed by UV-visibl. spectrophotometer and macroscopic observation showed that the decol.riz.tion of Direct Bl.ck 22 by mycel.al.pel.ets incl.des two important processes: bioadsorption and biodegradation. The degradation experiment agree with the Michael.s-Menten kinetics equation.

关键词： Bioassay Biodegradation Col.r Concentration (process) Dyes pH Ul.raviol.t spectrophotometers

Suppl.mental.Material.: Real.z.tion of Quantum Maxwel.'s Demon with Sol.d-State Spins

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Chinese Physics l.tters 2018年第4期35卷 1-6页

作者： W.-B. Wang X.-Y. Chang F. Wang P.-Y. Hou Y.-Y. Huang W.-G. z.ang X.-l. Ouyang X.-z. Huang z.-Y. z.ang H.-Y. Wang l. he l.-M. Duan Center for Quantum Information IIIS Tsinghua University Beijing 100084 Department of Physics University of Michigan Ann Arbor Michigan 48109 USA

We report experimental.real.z.tion of a quantum version of Maxwel.＇s demon using sol.d state spins where the information acquiring and feedback operations by the demon are achieved through conditional.quantum gates.A unique feature of this impl.mentation is that the demon can start in a quantum superposition state or in an entangl.d state with an ancil.a observer. Through quantum state tomography, we measure the entropy in the system, demon, and the ancil.a, showing the infl.ence of coherence and entangl.ment on the resul.. A quantum impl.mentation of Maxwel.＇s demon adds more control.abil.ty to this paradoxical.thermal.machine and may find appl.cations in quantum thermodynamics invol.ing microscopic systems.

关键词： Maxwel. Real.z.tion of Quantum Maxwel.’s Demon with Sol.d-State Spins

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Studies of Optical.Nonl.nearity Behaviors of Ul.rafine PbS Particl.s in Perfl.orocarboxyl.ted Cation-exchanged Fil.s

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High Technol.gy l.tters 1995年第1期1卷 102-104页

作者： Xiaowen, z.. Xueping, l. Yuan, l. Xurui, X. Songbin, z.. z.ngju, X. Yinghua, z. Academia Sinica Beijing China

Ul.rafine PbS particl.s with different siz.s have been prepared in perfl.orocarboxyl.ted cation-exchanged fil.s. The variation of PbS particl. siz. was cl.rified by absorption spectra and TEM graphs. Time-resol.ed optical.Kerr effects were measured by femtosecond pump-probe techniques. Optical.Kerr effect response time was estimated to be l.ss than 165 fs. A third-order optical.nonl.nearity of χ(3)10-12 esu for PbS particl.s was obtained and it was found that it increases with the decrease of particl. siz.s, showing the infl.ence of quantum confined effect on optical.nonl.near behaviour of ul.rafine particl.s.

关键词： PbS Ul.rafine particl. Optical.nonl.nearity Optical Kerr effect

Tunabl. near- to mid-infrared pump terahertz.probe spectroscopy in refl.ction geometry

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Frontiers of physics 2017年第5期12卷 81-85页

作者： S. J. z.ang z. X. Wang T. Dong N. l. Wang International.Center for Quantum Material. School of Physics Peking University Beijing 100871 China Col.aborative Innovation Center of Quantum Matter Beijing 100871 China

Strong-fiel. mid-infrared pump-terahertz.（THz.probe spectroscopy has been proven as a powerful.tool.for l.ght control.of different orders in strongl. correl.ted material.. We report the construction of an ul.rafast broadband infrared pump-THz.probe system in refl.ction geometry. A two-output optical.parametric ampl.fier is used for generating mid-infrared pul.es with GaSe as the nonl.near crystal. The setup is capabl. of pumping bul. material. at wavel.ngths ranging from 1.2 μm to 15 μm and beyond, and detecting the subtl., transient photoinduced changes in the refl.cted el.ctric fiel. of the THz.probe at different temperatures. As a demonstration, we present 15 μm pump-THz.probe measurements of a bul. EuSbTe3 singl. crystal. A 0.5% transient change in the refl.cted THz.el.ctric fiel. can be cl.arl. resol.ed. The widel. tuned pumping energy coul. be used in mode-sel.ctive excitation experiments and appl.ed to many strongl. correl.ted el.ctron systems.

关键词： mid-infrared pump terahertz.spectroscopy

An expl.cit sol.tion to a three-dimensional.wedge probl.m considering two edges effect

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Friction 2020年第2期8卷 370-383页

作者： l.GUO z.M.z.ANG W.WANG Y.z.AO P.l.WONG School.of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444China Department of Mechanical.Engineering City University of Hong KongHong Kong SARChina

The paper presents an expl.cit matrix al.orithm to sol.e the probl.m of an el.stic wedge with three l.aded *** al.orithm makes use of a recentl. publ.shed concept of transformation matrix,by which the original.surface l.ads are converted to equival.nt l.ads in *** three l.aded edges are considered *** devel.ped al.orithm is used to study the effects of two free edges of a steel.bl.ck and tapered rol.ers with different contact *** two l.ad-free edges can substantial.y increase deformation if the two edges are cl.se in *** resul.s of the tapered rol.er simul.tion show that deformation is considerabl. sensitive to the contact angl. of the tapered *** l.rgest deformation appears at the big end of the ***,empirical.formul.e for correction factors for the cal.ul.tion of bl.ck or quarter-space deformation based on hal.-space sol.tions are summariz.d.

关键词： contact mechanics two edge surfaces finite l.ne contact tapered rol.er contact

Friction and wear behaviors of a gradient nano-grained AISI 316l.stainl.ss steel.under dry and oil.l.bricated conditions

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Journal.of Material. Science & Technol.gy 2018年第10期34卷 1835-1842页

作者： P.F. Wang z. Han Shenyang National.l.boratory for Material. Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China University of Chinese Academy of Sciences Beijing 100049 China

A gradient nano-grained （GNG） surface l.yer was fabricated on an AIS1316l.stainl.ss steel.（SS） by using the surface mechanical.rol.ing treatment （SMRT）. Reciprocating dry and oil.l.bricated sl.ding tests of the GNG 316l.SS in air at room temperature were conducted in comparison with the coarse-grained （CG） counterpart. Worn surface morphol.gies and subsurface microstructures were investigated for both 316l.SS sampl.s. 316l.SS with a GNG surface l.yer shows a significantl. improved wear resistance, especial.y under oil.l.bricated condition. The notabl. wear resistance enhancement of the GNG 316l.SS is attributed to the GNG surface l.yer with high strain accommodation abil.ty and high hardness, which can reduce the wear vol.me in the running-in stage effectivel..

关键词： Austenitic stainl.ss steel Gradient nano-grained surface l.yer Friction and wear Running-in

MECHANISM AND KINETICS OF TRANSFORMATION OF Al.MINA INCl.SIONS BY CAl.IUM TREATMENT

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Acta Metal.urgica Sinica(Engl.sh l.tters) 2006年第1期19卷 1-8页

作者： z.J. Han l. l.u M. l.nd l. Hol.ppa Central.Iron and Steel.Research Institute Beijing 100081 China l.boratory of Metal.urgy Helsinki University of Technology P.O. Box 6200Espoo 02015 Finland

The basic mechanism and kinetics of the transformation process of al.mina incl.sions in steel.was reported when cal.ium introduced into the steel.by wire feeding orpowder injection. To cl.rify the mechanisms model. experiments were performed by studying reactions between Al.Os and CaO in a l.boratory furnace and by performing cal.ium treatments in an 8kg induction furnace for Al.deoxidised mel.. The phases formed during the reaction between Al.O3 and CaO were examined by SEM-EDS （scanning el.ctron microscope-energy dispersive spectrometer）, and the reaction sequence of Al.O3=〉 CA6=〉 CA2 =〉 CA =〉 CAx（l. was discussed in term of the experimental.observations. The kinetics of the reaction of cal.ium with al.mina incl.sions were simul.ted by immersing al.mina pl.tes in a Ca treated steel.mel. in the induction furnace. Resul.s were compared with observations of real.incl.sion transformation. A kinetic model.was proposed based on the resul.s.

关键词： mechanism kinetics al.mina incl.sion transformation