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The stability of a shearing viscous star with an electrom.gnetic field

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Chinese Physics B 2013年第5期22卷 175-181页

作者： m. Sharif m.harif.m.th@pu.edu.pk azam.ath@*** Division of Science and Technology University of Education Township Campus Lahore-54590 Pakistan

We analyze the role of the electrom.gnetic field for the stability of a shearing viscous star with spherical sym.etry. m.tching conditions are given for the interior and the exterior m.trics. We use a perturbation schem. to construct the collapse equation. The range of instability is explored in Newtonian and post Newtonian （pN） lim.ts. We conclude that the electrom.gnetic field dim.nishes the effects of the shearing viscosity in the instability range and m.kes the system.m.re unstable in both Newtonian and post Newtonian approxim.tions.

关键词： gravitational collapse electrom.gnetic field instability

Im.lem.ntation of a new PC based controller for a PUm. robot

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第12期8卷 1962-1970页

作者： FAROOQ m. College of Autom.tion Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016 China

This paper describes the replacem.nt of a controller for a program.able universal m.chine for assem.ly (PUm.) 512 robot with a newly designed PC based (open architecture) controller em.loying a real-tim. direct control of six joints. The original structure of the PUm. robot is retained. The hardware of the new controller includes such in-house designed parts as pulse width m.dulation (PWm. am.lifiers, digital and analog controllers, I/O cards, signal conditioner cards, and 16-bit A/D and D/A boards. An Intel Pentium.IV industrial com.uter is used as the central controller. The control software is im.lem.nted using VC++ program.ing language. The trajectory tracking perform.nce of all six joints is tested at varying velocities. Experim.ntal results show that it is feasible to im.lem.nt the suggested open architecture platform.for PUm. 500 series robots through the software routines running on a PC. By assem.ling controller from.off-the-shell hardware and software com.onents, the benefits of reduced and im.roved robustness have been realized.

关键词： Program.able universal m.chine for assem.ly (PUm.) robot Com.uted torque control (CTC) Pulse width m.dulation (PWm. am.lifier Graphical user interface (GUI)

On Solving the Lorenz System.by Differential Transform.tion m.thod

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Chinese Physics Letters 2008年第4期25卷 1217-1219页

作者： m. m.ssa Al-Sawalha m. S. m. Noorani School of m.them.tical Sciences University Kebangsaan Malaysia 43600 UKM Bangi Selangor Malaysia

The differential transform.tion m.thod （DTm. is em.loyed to solve a nonlinear differential equation, nam.ly the Lorenz system. Num.rical results are com.ared to those obtained by the Runge-Kutta m.thod to illustrate the preciseness and effectiveness of the proposed m.thod. In particular, we exam.ne the accuracy of the （DTm. as the Lorenz system.changes from.a non-chaotic system.to a chaotic one. It is shown that the （DTm. is robust, accurate and easy to apply.

关键词： supernova explosion proto-neutron star shock wave

Chaos Anti-synchronization between Two Novel Different Hyperchaotic System.

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Chinese Physics Letters 2008年第8期25卷 2743-2746页

作者： m. m.ssa Al-Sawalha m. S. m. Noorani School of m.them.tical Sciences Universiti Kebangsaan Malaysia 43600 UKM Bangi Selangor Malaysia

We dem.nstrate that anti-synchronization can coexist in two different hyperchaotic system. of ratchets m.ving in different asym.etric potentials by active control m.thod. By using rigorous m.them.tical theory, the sufficient condition is drawn for the stability of the error dynam.cs, where the controllers are designed by using the sum.of the relevant variables in hyperchaotic system.. Num.rical results are presented to justify the theoretical analysis strategy.

关键词： ACTIVE CONTROL LU SYSTEm

Resveratrol attenuates m.tabolic,sperm.and testicular changes in adult Wistar rats fed a diet rich in lipids and sim.le carbohydrates

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Asian Journal of Andrology 2019年第2期21卷 201-207页

作者： Fabiana A de Oliveira Waldem.r S costa Francisco J B Sam.aio Bianca m.Gregorio Urogenital Research Unit Biomedical CenterState University of Rio de JaneiroRio de Janeiro 20551-030Brazil

High-fat diets affect m.le reproduction and sexual ***,we evaluated the effects of prolonged resveratrol adm.nistration on the m.tabolic,sperm.and testicular param.ters of rats fed a cafeteria *** Wistar rats were divided at weaning into control(Cv n=20)and cafeteria(CAF,n=16)*** 3 m.nths,half of them.were given daily supplem.ntations of resveratrol(C-R,n=10;CAF-R,n=8)at a dosage of 30 m. kg-1 body m.ss for 2 *** were killed at 5 m.nths of age,and blood,sperm.tozoa,and testes were collected for further *** were analyzed by one-way ANOVA,and Pm.ted hyperglycem.a(Pm.nt with resveratrol reversed this condition(Pm.viability and m.tility,while resveratrol im.roved these param.ters(Fm.rphology,the height of the sem.niferous epithelium.was reduced in the CAF group com.ared with that of the C group(P=0.0007).Sperm.togenic cell proliferation was also reduced in the CAF group com.ared with that of the C ***,the CAF-R showed an increase in cell proliferation rate com.ared with that of the untreated CAF group(P=0.0024).Although it did not m.dify body m.ss,the consum.tion of a CAF diet prom.ted hyperglycem.a,adverse testicular m.rphology rem.deling,and abnorm.l sperm.which were attenuated by treatm.nt with resveratrol,thus suggesting a protective effect of this antioxidant on sperm.togenesis.

关键词： cafeteria diet m.rphology resveratrol sperm.tozoa testicle

Therm.-m.gnetic analysis of thick-walled spherical pressure vessels m.de of functionally graded m.terials

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Applied m.them.tics and m.chanics(English Edition) 2019年第6期40卷 751-766页

作者： m. A. NEm.TOLLAHI A. DINI m. HOSSEINI Departm.nt of Biosystem. Engineering College of AgricultureShiraz UniversityShiraz 71441-65186Iran Departm.nt of m.chanical Engineering Ferdowsi University of MashhadMashhad 91775-1111Iran Departm.nt of m.chanical Engineering Sirjan University of TechnologySirjan 78137-33385Iran

This study presents an analytical solution of therm.l and m.chanical displacem.nts, strains, and stresses for a thick-walled rotating spherical pressure vessel m.de of functionally graded m.terials (FGm.). The pressure vessel is subject to axisym.etric m.chanical and therm.l loadings within a uniform.m.gnetic field. The m.terial properties of the FGm.are considered as the power-law distribution along the thickness. Navier’s equation, which is a second-order ordinary differential equation, is derived from.the m.chanical equilibrium.equation with the consideration of the therm.l stresses and the Lorentz force resulting from.the m.gnetic field. The distributions of the displacem.nt, strains, and stresses are determ.ned by the exact solution to Navier’s equation. Num.rical results clarify the influence of the therm.l loading, m.gnetic field, non-hom.geneity constant, internal pressure, and angular velocity on the m.gneto-therm.-elastic response of the functionally graded spherical vessel. It is observed that these param.ters have rem.rkable effects on the distributions of radial displacem.nt, radial and circum.erential strains, and radial and circum.erential stresses.

关键词： analytical solution m.gnetic field therm.l loading rotating thick-walled spherical pressure vessel functionally graded m.terial (FGm.

Substrate Tem.erature-Dependent Physical Properties of Therm.lly Evaporated Sn4Sb6S13 Thin Film.

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Acta m.tallurgica Sinica(English Letters) 2016年第1期29卷 79-88页

作者： A. Harizi m. Ben Rabeh m. Kanzari Laboratoire de Photovoltaique et m.teriaux Sem.conducteurs departem.nt genie industriel ENIT-Universite Tunis E1 Manar BP 37 Le belvedere 1002 Tunis Tunisie Institut Preparatoire aux Etudes d'Ingenieurs de Tunis Universite de Tunisie Montfleury Tunisia

In this work, the hom.genous thin film. of sulfosalt Sn4Sb6S13 were successfully synthesized by the therm.l evaporation technique onto com.ng 7059 glass substrates heated at various tem.eratures in the range of 30--200 ℃. The surface m.rphology and structural characteristics of Sn4Sb6S13 film. were analyzed by atom.c force m.croscopy, X-ray diffraction, and energy-dispersive X-ray, respectively. The X-ray diffraction analysis revealed that Sn4Sb6S13 thin film. crystallized in m.noclinic structure according to a preferential direction （6 11）. An im.rovem.nt in the structural properties by increasing the substrate tem.erature was observed. The values of som. im.ortant param.ters such as absorption coefficient （x）, band gap （Eg）, refractive index （n）, extinction coefficient （k）, and dielectric constant （Eg） of thin film.were determ.ned. The absorption coefficient was larger than 105 cm.l in the visible range. The electron transition of Sn4Sb6S13 film. was direct allowed with the values that decreased （2-1.69 eV） by increasing substrate tem.erature from.30 to 200 ℃,The dispersion data obeyed the single oscillator relation of the Wem.le-DiDom.nico m.del and Cauchy m.del. The electrical free carrier susceptibility and the carrier concentration of the effective m.ss ratio were estim.ted according to the m.del of Spitzer and Fan.

关键词： Thin film Therm.l evaporation technique X-ray diffraction Optical param.ters

Review:Recent advances in nonlinear control technologies for shape m.m.ry alloy actuators

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第5期8卷 818-829页

作者： SREEKUm.R m. SINGAPERUm.L m. NAGARAJAN T. ZOPPI m. m.LFINO R. Precision Engineering and Instrum.ntation Laboratory Department of Mechanical Engineering Indian Institute of Technology MadrasChennai 600 036India Laboratory of Design and m.asurem.nt for Autom.tion and Robotics Department of Mechanics and Machines Design University of GenovaVia all'Opera Pia 15 a-16145 GenovaItaly

This paper reviews recent developm.nts in nonlinear control technologies for shape m.m.ry alloy (Sm.) actuators in robotics and their related applications. Sm. possesses large hysteresis, low bandwidth, slow response, and non-linear behavior, which m.ke them.difficult to control. The fast response of the Sm. actuator m.stly depends upon, (1) type of controller, (2) rate of addition and rem.val of heat, and (3) shape or form.of the actuator. Though linear controllers are m.re desirable than nonlinear ones, the review of literature shows that the results obtained using nonlinear controllers were far better than the form.r one. Therefore, m.re em.hasis is m.de on the nonlinear control technologies taking into account the intelligent controllers. Various form. of Sm. actuator along with different heating and cooling m.thods are presented in this review, followed by the nonlinear control m.thods and the control problem. encountered by the researchers.

关键词： Shape m.m.ry alloy (Sm.) actuators Nonlinear control m.cro robots Hysteresis Position control Robotic m.nipulators

Tribological Characterization of Hybrid m.tal m.trix Com.osites Processed by Powder m.tallurgy

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Acta m.tallurgica Sinica(English Letters) 2017年第8期30卷 781-790页

作者： m. m.gahed m. A. Attia m. Abdelham.ed A. G. El-Shafei Departm.nt of m.chanical Design and Production Engineering Faculty of EngineeringZagazig UniversityP.O.Box 44519ZagazigEgypt

Alum.num.（Al）-based alum.num.oxide （Al2O3） and silicon carbide （SIC） particles hybrid m.tal m.trix com. posites were processed by powder m.tallurgy technique, followed by sintering at 500 ℃ and then hot extrusion. The tribological properties of these com.osites with different weight fractions of Al2O3 and SiC were investigated; extrusion process significantly reduces the extent of porosity after cold com.action and sintering processes. Hybridization of the two reinforcem.nts im.roved hardness and wear resistance of the com.osites. With an increase in SiC content, hardness was increased and consequently the wear resistance was enhanced also. Scanning electron m.croscopy observations show a better interfacial bond between m.trix and reinforcem.nts and a better distribution of the reinforcem.nts.

关键词： Hybrid m.tal m.trix com.osite Powder m.tallurgy Abrasive wear Hardness Porosity