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JUMPING INSTABILITIES IN THE POST-BUCKLING OF A BEAM ON A PARTIAL NONLINEAR FOUNdATION

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Acta Mechanica Solida Sinica 2013年第5期26卷 500-513页

作者： Yin Zhang Kevin d Murphy State Key Laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences department of Mechanical Engineering University of Connecticut

Mode jumping is an instability phenomenon in the post-buckling region, which causes a sudden change in the equilibrium configuration and is thus harmful to structure. The con- figuration of a partial elastic foundation can directly induce mode coupling from the buckling stage and through the whole post-buckling region. The mode coupling effect due to the configuration of partial foundation on mode jumping is investigated and demonstrated to be an important factor of determining mode jumping. By properly choosing the partial elastic foundation configuration, mode jumping can be avoided.

关键词： instability mode jumping tertiary jumping buckling beam elastic foundation

PYRIdINATION OF POLY(VINYL CHLORIdE) via A HOMOLYTIC PATHWAY

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Chinese Journal of Polymer Science 2007年第3期25卷 297-302页

作者： Sad Moulay Zakia Zeffouni Laboratoire de Chimie-Physique Moléculaire et Macromoléculaire Faculté des Sciences de l'Ingénieur Département de Chimie IndustrielleUniversité Sad Dahlab de BlidaRoute de SoumaB. P. 270Blida 09000Algeria

PVC was subjected to a chemical modification aiming at replacing the chlorine atoms by pyridine groups via a homolytic route. Pyridine groups were peculiarly affixed to the PVC matrix via a carbon-carbon bond rather than a carbonnitrogen one. PVC was first iodinated using the Conant-Finkelstein reaction, followed by the application of the homolytic conditions of Minisci to generate pyridinated PVC with a varying degree of substitution. The extent of substitution was not high; the reaction on 30% iodinated PVC afforded a degree of modification no greater than 3%.

关键词： Conditions of Minisci Iodinated PVC Pyridinated PVC

disappearance of the dirac cone in silicene due to the presence of an electric field

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Chinese Physics B 2014年第3期23卷 63-70页

作者： d.A.Rowlands 张宇钟 Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology School of Physics Science and EngineeringTongji University

Using the two-dimensional ionic Hubbard model as a simple basis for describing the electronic structure of silicene in the presence of an electric field induced by the substrate, we use the coherent-potential approximation to calculate tbe zero-temperature phase diagram and the associated spectral function at half filling. We find that any degree of symmetry- breaking induced by the electric field causes the silicene structure to lose its dirac fermion characteristics, thus providing a simple mechanism for the disappearance of the dirac cone.

关键词： silicene dirac cone ionic Hubbard model coherent-potential approximation

Micro-computed tomography utility for estimation of intraparenchymal spinal cord cystic lesions in small animals

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Neural Regeneration Research 2021年第11期16卷 2293-2298页

作者： Mahmoud Farrag dipak d.Pukale Nic d.Leipzig Integrated Bioscience Program The University of AkronAkronOHUSA department of Chemical Biomolecularand Corrosion EngineeringThe University of AkronAkronOHUSA department of Chemical Biomolecularand Corrosion EngineeringIntegrated Bioscience ProgramThe University of AkronAkronOHUSA

Precise assessment of spinal cord cystic lesions is crucial to formulate effective therapeutic strategies,yet histological assessment of the lesion remains the primary method despite numerous studies showing inconsistent results regarding estimation of lesion size via *** the other hand,despite numerous advances in micro-computed tomography(micro-CT)imaging and analysis that have allowed precise measurements of lesion size,there is not enough published data on its application to estimate intraspinal lesion size in laboratory animal *** work attempts to show that micro-CT can be valuable for spinal cord injury research by demonstrating accurate estimation of syrinx size and compares between micro-CT and traditional histological *** used a post-traumatic syringomyelia rat model to compare micro-CT analysis to conventional histological *** study showed that micro-CT can detect lesions within the spinal cord very similar to ***,micro-CT appears to provide more accurate estimates of the lesions with more measures(e.g.,surface area),can detect compounds within the cord,and can be done with the tissue of interest(spinal cord)*** summary,the experimental work presented here provides one of the first investigations of the use of micro-CT for estimating the size of intraparenchymal cysts and detecting materials within the spinal *** animal procedures were approved by the University of Akron Institutional Animal Care and Use Committee(IACUC)(protocol#LRE 16-05-09 approved on May 14,2016).

关键词： cyst size histology intraparenchymal cysts lesion size estimate micro-CT post-traumatic syringomyelia spinal cord imaging spinal cord injury spinal cystic lesion syrinx

Couple stress nanofluid flow through a bifurcated artery—Application of catheterization process

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Applied Mathematics(A Journal of Chinese Universities) 2021年第4期36卷 492-511页

作者： KM Surabhi Arpitha Ravikanti d.Srikanth d.Srinivasacharya department of Applied Mathematics Defence Institute of Advanced Technology(Deemed University)Girinagar Pune 411025India department of Mathematics National Institute of TechnologyWarangal 506004India

In this article,we are exploring the hemodynamics of nanofluid,flowing through a bifurcated artery with atherosclerosis in the presence of a *** treating obstruction in the artery,one can use the catheter whose outer surface is carrying the drug coated with *** resultant solvent is considered as blood *** being a complex fluid,is modeled by couple stress *** the presence of nano-particles,the temperature and the concentration distribution are understood in a bifurcated stenotic *** concluded mathematical model is governed by coupled non-linear equations,and are solved by using the homotopy perturbation ***,we have explored is the effects of fluid and the embedded geometric parameters on the hemodynamics *** is also realized that high wall shear stress exists for couple stress nano-fluid when compared to Newtonian *** is computed at a location corresponding to maximum constriction(z=12.5)of the artery.

关键词： couple stress uid bifurcated stenotic artery homotopy perturbation method wall shear stress

Spin Number Coherent States and the Problem of Two Coupled Oscillators

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Communications in Theoretical Physics 2015年第7期64卷 34-38页

作者： d.Ojeda-Guillén R.d.Mota V.d.Granados Escuela Superior de Fisica y Matemáticas Instituto Politécnico Nacional Ed. 9 Unidad Profesional Adolfo López Mateos Escuela Superior de Ingenieria Mecánica y Eléctrica Unidad Culhuacán Instituto Politécnico Nacional

From the definition of the standard Perelomov coherent states we introduce the Perelomov number coherent states for any su(2) Lie algebra. With the displacement operator we apply a similarity transformation to the su(2)generators and construct a new set of operators which also close the su(2) Lie algebra, being the Perelomov number coherent states the new basis for its unitary irreducible representation. We apply our results to obtain the energy spectrum, the eigenstates and the partition function of two coupled oscillators. We show that the eigenstates of two coupled oscillators are the SU(2) Perelomov number coherent states of the two-dimensional harmonic oscillator with an appropriate choice of the coherent state parameters.

关键词： coherent states Lie algebras coupled oscillators

Analytical modelling of end thermal coupling in a solid-state laser longitudinally bonded by a vertical-cavity top-emitting laser diode

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Chinese Physics B 2009年第11期18卷 4912-4918页

作者：吴坚 H.d.Summers School of Physics Beijing University of Aeronautics and Astronautics School of Physics and Astronomy Cardiff University

The intrinsic features involving a circularly symmetric beam profile with low divergence, planar geometry as well as the increasingly enhanced power of vertical-cavity surface-emitting lasers （VCSELs） have made the VCSEL a promising pump source in direct end bonding to a solid-state laser medium to form the minimized, on-wafer integrated laser system. This scheme will generate a surface contact pump configuration and thus additional end thermal coupling to the laser medium through the joint interface of both materials, apart from pump beam heating. This paper analytically models temperature distributions in both VCSEL and the laser medium from the end thermal coupling regarding surface contact pump configuration using a top-emitting VCSEL as the pump source for the first time. The analytical solutions are derived by introducing relative temperature and mean temperature expressions. The results show that the end contact heating by the VCSEL could lead to considerable temperature variations associated with thermal phase shift and thermal lensing in the laser medium. However, if the central temperature of the interface is increased by less than 20 K, the end contact heating does not have a significant thermal influence on the laser medium. In this case, the thermal effect should be dominated by pump beam heating. This work provides useful analytical results for further analysis of hybrid thermal effects on those lasers pumped by a direct VCSEL bond.

关键词： solid-state laser end pump thermal coupling vertical-cavity surface-emitting laser

An Iterative Relaxation Approach to the Solution of the Hamilton-Jacobi-Bellman-Isaacs Equation in Nonlinear Optimal Control

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IEEE/CAA Journal of Automatica Sinica 2018年第1期5卷 360-366页

作者： M.d.S.Aliyu department of Electrical Engineering King Faisal University Al-Ahsa 31982 Saudi Arabia IEEE

In this paper, we propose an iterative relaxation method for solving the Hamilton-Jacobi-Bellman-Isaacs equation(HJBIE) arising in deterministic optimal control of affine nonlinear systems. Local convergence of the method is established under fairly mild assumptions, and examples are solved to demonstrate the effectiveness of the method. An extension of the approach to Lyapunov equations is also discussed. The preliminary results presented are promising, and it is hoped that the approach will ultimately develop into an efficient computational tool for solving the HJBIEs.

关键词： Affine nonlinear system bounded continuous function convergence Hamilton-Jacobi-Bellman-Isaacs equation Lyapunov equation relaxation method Riccati equation

THEORY OF WATER WAVES IN AN ELASTIC VESSEL

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Acta Mechanica Sinica 2000年第2期16卷 97-112页

作者： d. Y. Hsieh division of Applied Mathematics Brown University USA

Recent experiments related to the dragon Wash phenomena showed that axisymmetric capillary waves appear first from excitation, and circumferential capillary waves appear after increase of the excitation strength. Based on this new finding, a theory of parametric resonance is developed in detail to explain the on- set of the prominent circumferential capillary waves. Numerical computation is also carried out and the results agree generally with the experiments. Analysis and nu- merical computation are also presented to explain the generation of axisymmetric low-frequency gravity waves by tile high-frequency external excitation.

关键词： water waves elastic vessel dragon Wash