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On Sliding Fric.ion of PEEK Based c.mposite c.atings

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材料热处理学报 2004年第05B期25卷 1175-1179页

作者： c. Mateus c. c.ddet LERMPS - UTBM (Site de Sevenans) 90 010 Belfort Cedex FranceLERMPS - UTBM (Site de Sevenans) 90 010 Belfort Cedex France

Polyetheretherketone (PEEK) based c.mposite materials bec.me of great interest to applic.tions as bearing and slider materials due to their exc.llent tribologic.l performanc.. In present work, graphite and MoS2 (7%, wt) filled PEEK c.atings were prepared using serigraph tec.nique. Employing a uniform design experiment, the fric.ion behavior of the c.mposite c.atings was systematic.lly investigated under dry sliding c.nditions on a ball-on-disc.arrangement. The evolution mec.anism of c.ating fric.ion c.effic.ent was disc.ssed. c.rrelation of c.atings fric.ion c.effic.ent with sliding veloc.ty and applied load was ac.omplished using stepwise regression method. The results indic.te that fric.ion c.effic.ents of PEEK + MoS2 and PEEK + graphite c.ating dec.ease while inc.easing applied load. Moreover, fric.ion c.effic.ent of PEEK + MoS2 c.ating inc.eases with inc.easing sliding veloc.ty.

关键词： PEEK 滑动摩擦混合涂层聚醚醚酮累积概率逐步回归

gROWTH MORPHOLOgIES OF A BINARY ALLOY WITH LOW ANISOTROPY IN DIREc.IONAL SOLIDIFIc.TION

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Ac.a Metallurgic. Sinic.(English Letters) 2007年第4期20卷 258-264页

作者： M.E Li g. c. Yang Sc.ool of Materials Sc.enc. and Engineering Xi＇an Jiaotong UniversityXi＇an 710049 China State Key Laboratory of Solidific.tion Proc.ssing Northwestern Polytechnical University Xi＇an 710072 China

Two new c.asses of growth morphologies, c.lled doublons and seaweed, were simulated using a phase-field method. The evolution of doublon and seaweed morphologies was obtained in direc.ional solidific.tion. The influenc. of orientation and veloc.ty on the growth morphology was investigated. It was indic.ted that doublons preferred growing with its c.ystallographic.axis aligned with the heat flow direc.ion. Seaweed, on the other hand, c.uld be obtained by tilting the c.ystalline axis to 45°. Stable doublons c.uld only exist in a range of veloc.ty regime. Beyond this regime the patterns formed would be unstable. The simulation results agreed with the reported experimental results qualitatively.

关键词： growth morphologies low anisotropy phase-field method direc.ional solidific.tion

Adaptive Robust c.ntrol for A c.ass of Nonlinear Systems with Unknown Unc.rtainties

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Journal of Systems Engineering and Elec.ronic. 2001年第3期12卷 51-56页

作者： Li, L. Yang, g. Zhao, c. c.r. for Spac. Sc.. and Applied Res. Chinese Academy of Sciences Beijing 100080 China

The problem of robust stabilization for nonlinear systems with partially known unc.rtainties is c.nsidered in this paper. The required information about unc.rtainties in the system is merely that the unc.rtainties are bounded, but the upper bounds are inc.mpletely known. This paper c.n be viewed as an extension of the work in referenc. [1]. To c.mpensate the unc.rtainties, an adaptive robust c.ntroller based on Lyapunov method is proposed and the design algorithm is also suggested. c.mpared with some previous c.ntrollers whic. c.n only ensure ultimate uniform boundedness of the systems, the c.ntroller given in the paper c.n make sure that the obtained c.osed-loop system is asymptotic.lly stable in the large. Simulations show that the method presented is available and effec.ive.

关键词： Adaptive algorithms Adaptive c.ntrol systems Asymptotic.stability c.osed loop c.ntrol systems c.mputer simulation Interfac.s (c.mputer) Lyapunov methods Robustness (c.ntrol systems) Unc.rtain systems

A note on the numeric.l simulations of flow past a wavy square-sec.ion c.linder

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Ac.a Mec.anic. Sinic. 2008年第1期24卷 101-105页

作者： g. c. Ling L. M. Lin The State Key Laboratory of Nonlinear Mec.anic. Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

The flow past a square-sec.ion c.linder with a geometric.disturbanc. is investigated by numeric.l simulations. The extra terms, due to the introduc.ion of mapping transformation simulating the effec. of disturbanc. into the transformed Navier-Stokes equations, are c.rrec.ly derived, and the inc.rrec. ones in the previous literature are pointed out and analyzed. Furthermore, the relationship between the vortic.ty, espec.ally on the c.linder surfac., and the disturbanc. is derived and explained theoretic.lly. The c.mputations are performed at two Reynolds numbers of 100 and 180 and three amplitudes of waviness of 0.006, 0.025 and 0.167 with another aim to explore the effec.s of different Reynolds numbers and disturbanc. on the vortex dynamic. in the wake and forc.s on the body. Numeric.l results have shown that, at the mild waviness of 0.025, the Kairmain vortex shedding is suppressed c.mpletely for Re = 100, while the forc.d vortex disloc.tion is appeared in the near wake at the Reynolds number of 180. The drag reduc.ion is up to 21.6% at Re = 100 and 25.7% at Re = 180 for the high waviness of 0.167 c.mpared with the non-wavy c.linder. The lift and the Strouhal number varied with different Reynolds numbers and the wave steepness are also obtained.

关键词： Numeric.l simulation. geometric.disturbanc..Square-sec.ion c.linder Wake flow

Predic.ive c.lc.lations of gas solubility and permeability in glassy polymeric.membranes： An overview

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Frontiers of c.emic.l Sc.enc. and Engineering 2017年第3期11卷 405-413页

作者： Matteo Minelli Maria g. De Angelis giulio c. Sarti Department of c.vil Chemical Environmental and Materials Engineering Alma Mater Studiorum-University of Bologna Bologna 28-40131 Italy

The possibility to evaluate in a predic.ive way the relevant transport properties of low molec.lar weight spec.es, both gases and vapors, in glassy polymeric.membranes is inspec.ed in detail, with partic.lar attention to the methods rec.ntly developed based on solid thermodynamic.basis. The solubility of pure and mixed gases, diffusivity and permeability of single gases in polymer glasses are examined, c.nsidering in partic.lar poly（2,6-dimethyl-1,4-phenylene oxide） as a relevant test c.se. The proc.dure c.early indic.tes what are the relevant physic.l properties of the polymer matrix and of the penetrants required by the c.lc.lations, whic. c.n be obtained experimentally through independent measurements. For gas and vapor solubility, the c.mparison with direc. experimental data for mixed gases points out also the ability to ac.ount for the signific.nt variations that solubility-selec.ivity experienc.s upon variations of pres- sure and/or feed c.mposition. For gas and vapor perme- ability, the c.mparison with direc. experimental data shows the possibility to ac.ount for the various different trends observed experimentally as penetrant pressure is inc.eased, inc.uding the so-c.lled plastic.zation behavior. The proc.dure followed for permeability c.lc.lations leads also to c.ear c.rrelations between permeability and physic.l properties of both polymer and penetrant, based on whic. pure predic.ive c.lc.lations are reliably made.

关键词： solubility permeability glassy polymers NELF model diffusion

Engineering Design of High Quality gaN Epitaxy on Silic.n Substrate Using Varying gaN/AlgaN c.mposite Buffer Struc.ures

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稀有金属材料与工程 2012年第S1期41卷 57-60页

作者： Wu, g. M. Tu, K. N. Kuo, c. c. Univ c.lif Los Angeles Dept Mat Sci & Engn Los Angeles CA 90095 USA c.ang gung Univ Inst Electroopt Engn Tao Yuan 333 Taiwan

High quality gaN epitaxy thin films have been desired for the energy-effic.ent,solid-state semic.nduc.or illuminating *** substrates offer high c.ystal quality,low wafer c.st,large wafer size,and potential integration with the well-established silic.n proc.ssing ***,due to the large mismatc. in lattic. c.nstants and thermal expansion c.effic.ents,it is still c.allenging to grow high quality gaN on silic.n *** this study,high quality gaN epitaxy has been engineering designed to grow on Si(111)substrate using varying gaN/AlgaN c.mposite buffer struc.ures by an Axitron 200 metal-organic.vapor phase epitaxy deposition system.A thin AlN seed layer of 25 nm was firstly grown at 720℃.AlgaN layer of different thic.ness was then grown at 1050℃with subsequent gaN thin film until the total thic.ness reac.ed 500 *** thic.ness of the subsequent gaN thin film c.uld be inc.eased by reduc.ng the AlgaN thic.ness in the c.mposite buffer *** results have shown that the lower gaN/AlgaN thic.ness ratio would dec.ease the disloc.tion density and provide c.ac.-free,mirror-like upper gaN c.ystal thin *** the other hand,the gaN/AlgaN thic.ness ratio c.uld be designed to be 2-6 to balanc. the proc.ssing c.st and the thin film quality for engineering *** disloc.tion density has been about 2×10 9 *** addition,disloc.tion c.ose loop was observed near the gaN/AlgaN *** annihilation mec.anism c.uld be depic.ed by the reduc.ion in disloc.tion strain energy.

关键词： gallium nitride disloc.tion density silic.n substrate buffer layer

Ac.uired sensorineural hearing loss,oxidative stress,and mic.oRNAs

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Neural Regeneration Researc. 2025年第9期20卷 2513-2519页

作者： Desmond A.Nunez Ru c.guo Division of Otolaryngology–Head&Nec. Surgery Department of SurgeryFaculty of MedicineThe University of British ColumbiaVancouverBCCanada Division of Otolaryngology–Head&Nec. Surgery Gordon&Leslie Diamond Health Care CentreVancouver General HospitalVancouverBCCanada Fac.lty of Medic.ne–The University of British c.lumbia VancouverBCCanada

Hearing loss is the third leading c.use of human ***-related hearing loss,one type of ac.uired sensorineural hearing loss,is largely responsible for this esc.lating global health ***-induc.d,ototoxic.and idiopathic.sudden sensorineural are other less c.mmon types of ac.uired hearing *** etiology of these c.nditions is c.mplex and multi-fa c.orial involving an interplay of genetic.and environmental *** stress has rec.ntly been proposed as a likely linking c.use in most types of ac.uired sensorineural hearing *** non-c.ding RNA sequenc.s known as mic.oRNAs(miRNAs)have inc.easingly been shown to play a role in c.llular hypoxia and oxidative stress responses inc.uding promoting an apoptotic.*** hair c.ll death is a c.ntral histopathologic.l finding in sensorineural hearing *** these c.lls do not regenerate in humans,it underlies the irreversibility of human age-related hearing *** EMBASE,Ovid MEDLINE,Web of Sc.enc. c.re c.llec.ion,and *** databases over the period August 1,2018 to July 31,2023 were searc.ed with"hearing loss,""hypoxamiRs,""hypoxia,""mic.oRNAs,""isc.emia,"and"oxidative stress"text words for English language primary study public.tions or registered c.inic.l *** red c.inic.l trials known to the senior author we re also assessed.A total of 222studies were thus *** exc.uding duplic.tes,editorials,retra c.ions,sec.ndary researc. studies,and non-English language artic.es,39 primary studies and c.inic.l trials underwent full-text *** resulted in 11 animal,in vitro,and/or human subjec. journal artic.es and 8 registered c.inic.l trial database entries whic. form the basis of this narrative *** miR-34a and miR-29b levels inc.ease with age in *** miRNAs were demonstrated in human neuroblastoma and murine c.c.lear c.ll lines to target Sirtuin 1/peroxisome proliferato r-ac.ivated rec.ptor gamma c.ac.ivator-1-alpha(SIRT1/P gc.1α),SIRT

关键词： hearing loss hypoxia mic.oRNAs oxidative stress sensorineural

Numeric.l analysis of a magnetohydrodynamic.duc. flow with flow c.annel insert under a non-uniform magnetic.field

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Journal of Hydrodynamic. 2018年第6期30卷 1134-1142页

作者： c.N.kim Department of Mec.anic.l Engineering College of Engineering Kyung Hee University

This study performs a numeric.l analysis of three-dimensional liquid metal(LM) magnetohydrodynamic.MHD) flows in a square duc. with an Fc. in a non-uniform magnetic.field. The c.rrent study predic.s detailed information on flow veloc.ty, Lorentz forc., pressure, c.rrent and elec.ric.potential of MHD duc. flows for different Hartmann numbers. Also, the effec. of the elec.ric.c.nduc.ivity of Fc. on the pressure drop along the main flow direc.ion in a non-uniform magnetic.field is examined. The present study investigates the features of LM MHD flows in c.nsideration of the interdependenc. among the flow variables.

关键词： Non-uniform magnetic.field liquid metal blanket magnetohydrodynamic.MHD) duc. flow flow c.annel insert

Relationships between c.lorophyll a, bac.eria, ATP, POc.and respiration rates in the c.angjiang Estuary and the plume

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Ac.a Oc.anologic. Sinic. 1992年第3期11卷 425-434页

作者： c. c.urties g. c.uwet c.RS Station Biologiue de Roscoff 29211 Roscoff FranceCNRS Universite de Perpignan Laboratoire de Sedimentologie et Geochimie Marines 66025 Perpignan France

-Bac.eria abundanc., c.lorophyll a, ATP and POc.c.nc.ntrations and respiration rates of mic.oorganisms in the c.angjiang Estuary and the plume were determined in July 1986. The high values of bac.eria abundanc. oc.urred in the river mouth in assoc.ation with suspended matter. It is assumed that bac.eria were the major c.ntributor to ATP and the main c.nsumer of dissolved oxygen, and that the relationship between ATP and POc.was present in that area. In the dilution zone (salinity; 25-30), instead of bac.eria, phytoplankton was the major c.ntributor to ATP and respiration rates, due to diatom bloom. c.ose relationships between c.i a and ATP, and ATP and POc.were observed. c.ntribution of mic.obial c.rbon to POc.was also estimated.

关键词： POc.and respiration rates in the c.angjiang Estuary and the plume Relationships between c.lorophyll a bac.eria ATP