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Th.rmal 9h.t Noise th.ough.Boundary Rough.ess of Carbon Nanotube Quantum Dots

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Ch.nese Ph.sics Letters 2011年第1期28卷 186-189页

作者： Attia A. Awadalla Adel h. Ph.llips Department of Ph.sics Faculty of Science Beni-Suef University Beni-Suef Egypt Department of Engineering Ph.sics and Math.matics Faculty of Engineering Ain Shams University Cairo Egypt

Th.rmal sh.t noise, th.rmal voltage and th.rmo power are studied th.ough.a carbon nanotube quantum dot coupled to two leads with.random rough.ess of amplitude on each.of th. two boundaries, under th. effect of microwave field, and magnetic field. Th. expressions for th. th.rmal sh.t noise and th.rmal energy are deduced wh.n th. barrier strength.and contact area are taken into consideration. A model for such.mesoscopic devices is proposed as a carbon nanotube quantum dot coupled to two leads with.random rough.ess of amplitude on each.of th. two boundaries. Th. results sh.w oscillatory beh.viors of th. dependence of th. th.rmal sh.t noise on th. studied parameters. Th. th.rmopower oscillates with.th. variation of th. contact area, and th. peak h.igh.s decrease linearly with.th. contact area and increases with.temperature. Th.s trend of beh.vior is due to th. interplay of th. induced microwave ph.tons and th. tunneling rate th.ough.th. side bands. Th.s research.is important for using a model as a h.gh.frequency sh.t noise detector and th. th.rmopower is sensitive to th. energy dependence of th. conductance.

关键词： Noise Energy Carbon Lead Carbonates Carbonation Models Boundaries Fields

Can h.avier Liquid Float on Top of a Ligh.er One？

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Ch.nese Ph.sics Letters 2011年第1期28卷 127-129页

作者： A. h. Ayyad F. Takrori Department of Ch.mistry Faculty of Science and Technology Hebron University P.O. Box 40 Hebron West Bank Palestine

We report on a first observation of a floating- sph.rical h. （density 13g/cm3） drop on top of a glycerin （density 1.26g/cm3） drop, th. latter is h.misph.rical and about four times larger in volume. Th.s observation is clearly against nature＇s gravity law and h.s never been reported before. h.re we present spectacular h.gh.resolution ph.tos th.t clearly demonstrate th.s remarkable floating ph.nomenon. Using milli-Q water, th. h. drop would stay down adh.red at th. triple line. Instead, th. coincidental use of tap water displays th. same ph.nomenon. Increasing th. volume of th. supporting liquid to a certain value causes th. h. drop to sink. A 5-M NaCl aqueous solution is found enough.to sh.w th. same floating ph.nomenon. Th.s floating mercury as a ph.nomenon is puzzling. On th.s length.scale it seems th.t surface tension and curvature dominate over gravity.

关键词： Soft matter liquids and polymers Fluid dynamics Surfaces interfaces and th.n films

A novel twice-interpolation finite element meth.d for solid mech.nics problems

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Acta Mech.nica Sinica 2010年第2期26卷 265-278页

作者： C. Zh.ng S. C. Wu X. h. Tang J. h. Zh.ng State Key Laboratory of h.draulics and Mountain River Engineering Sichuan University 610065 Chengdu China State Key Laboratory of Digital Manufacturing and Equipment Tech.ology Huazhong University of Science and Technology 430074 Wuhan China Department of Mech.nical Engineering Centre for Advanced Computations in Engineering Science (ACES)National University of Singapore Singapore 117576 Singapore

Formulation and numerical evaluation of a novel twice-interpolation finite element meth.d （TFEM） is presented for solid mech.nics problems. In th.s meth.d, th. trial function for Galerkin weak form is constructed th.ough.two stages of consecutive interpolation. Th. primary interpolation follows exactly th. same procedure of standard FEM and is furth.r reproduced according to both.nodal values and averaged nodal gradients obtained from primary interpolation. Th. trial functions th.s constructed h.ve continuous nodal gradients and contain h.gh.r order polynomial with.ut increasing total freedoms. Several bench.ark examples and a real dam problem are used to examine th. TFEM in terms of accuracy and convergence. Compared with.standard FEM, TFEM can ach.eve significantly better accuracy and h.gh.r convergence rate, and th. continuous nodal stress can be obtained with.ut any smooth.ng operation. It is also found th.t TFEM is insensitive to th. quality of th. elemental mesh. In addition, th. present TFEM can treat th. incompressible material with.ut any modification.

关键词： Twice-interpolation finite element meth.d·Stress smooth.ng Volumetric locking Mesh.distortion

Ph.se Control of Transient Optical Properties of Quantum-Dot Nanostructure via Terah.rtz Signal Radiation

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Ch.nese Ph.sics Letters 2014年第11期31卷 77-80页

作者： Seyyed h.ssein Asadpour h. Rah.mpour Soleimani Department of Ph.sics University of Guilan Rasht Iran

We th.oretically analyze th. transient properties of a probe field absorption dispersion in a quantum-dot nanos- trueture driven by terah.rtz signal radiation. h.re a four-level quantum-dot nanostructure is designed numerically by Sch.odinger and Poisson＇s equations. We sh.w th.t in th. presence of th. Th. signal, th. medium becomes ph.se dependent and th. absorption dispersion can be dramatically influenced by th. relative ph.se between applied fields.

关键词： Quantum dots Nanostructured materials Submillimeter waves Sch.ödinger equation Ph.sics research

An Analysis of th. Invariance and Conservation Laws of Some Classes of Nonlinear Ostrovsky Equations and Related Systems

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Ch.nese Ph.sics Letters 2011年第1期28卷 1-4页

作者： K. Fakh.r A. h. Kara Department of Math.matics Faculty of Science Universiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia Sch.ol of Math.matics and Centre for Differential Equations Continuum Mechanics and Applications University of the Witwatersrand Johannesburg P Bag 3 Wits 2050 South Africa

A large class of partial differential equations in th. modelling of ocean waves are due to Ostrovsky. We determine th. invariance properties （th.ough.th. Lie point symmetry generators） and construct classes of conservation laws for some of th. models. In th. latter case, th. meth.d involves finding th. ＇multipliers＇ associated with.th. conservation laws with.a stronger emph.sis on th. ＇h.gh.r-order＇ ones. Th. relationsh.p between th. symmetries and conservation laws is investigated by considering th. invariance properties of th. multipliers.

关键词： Math.matical ph.sics Statistical ph.sics and nonlinear systems

A novel mesh.free poly-cell Galerkin meth.d

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Acta Mech.nica Sinica 2009年第4期25卷 517-527页

作者： C. Zh.ng X. h. Tang J. h. Zh.ng S. C. Wu State Key Laboratory of h.draulics and Mountain River Engineering Sichuan University State Key Laboratory of Digital Manufacturing and Equipment Tech.ology Huazhong University of Science and Technology Centre for Advanced Computations in Engineering Science (ACES) Department of Mechanical EngineeringNational University of Singapore

A novel numerical meth.d is explored and named as mesh.free poly-cell Galerkin meth.d. An improved moving least-square （MLS） sch.me is presented, wh.ch.can avoid th. matrix inversion in standard MLS and can be used to construct sh.pe functions possessing delta Kronech.r property. A new type of local support is introduced to ensure th. alignment of integral domains with.th. cells of th. back-ground mesh. wh.ch.will reduce th. difficult in integration. An intensive numerical study is conducted to test th. accuracy of th. present meth.d. It is observed th.t solutions with.good accuracy can be obtained with.th. present meth.d.

关键词： MPG CO-MSL Mesh.free Mesh.ess Voronoi diagram

Study of th. Geometry and Folding Pattern of Leaves of Mimosa pudica

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Journal of Bionic Engineering 2007年第1期4卷 19-23页

作者： h. S. Patil Siddh.rth.Vaijapurkar Department of Applied Mech.nics S.V. National Institute of Technology Ichchanath Surat Gujarath 395007 India

Many structural and functional properties possessed by plants h.ve great potentials to stimulate new concepts and innovative ideas in th. field of biomimetic engineering. Th. key inputs from biology can be used for creation of efficient and optimized structures. Th. study of th. geometry and folding pattern of leaves of Mimosa pudica, referred as Sensitive Plant, reveals some of th. peculiar ch.racteristics during folding and unfolding. Wh.n th. leaf is touch.d, it quickly folds its leaflets and pinnae and droops downward at th. petiole attach.ent. With.th. h.lp of experiments on simulation model, th. variations in angle of leaflets and degree of compaction after folding are investigated.

关键词： bionics biomimetics folding geometry leaves Mimosa pudica

Determination of interface states and th.ir time constant for Au/SnO_2 /n-Si (MOS) capacitors using admittance measurements

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Ch.nese Ph.sics B 2013年第4期22卷 429-433页

作者： h. M. Baran A. Tataroglu Department of Ph.sics Faculty of Arts and Sciences Gazi University

Th. frequency dependence of admittance measurements （capacitance–voltage （C–V ） and conductance–voltage （G/ω–V ）） of Au/SnO2 /n-Si （MOS） capacitors was investigated by taking into account th. effects of th. interface states （N ss ） and series resistance （Rs ） at room temperature. Admittance measurements were carried out in frequency and bias voltage ranges of 1 kh.–1 Mh. and （ 5V）–（＋9V）, respectively. Th. values of N ss and R s were determined by using a conductance meth.d and estimating from th. admittance measurements of th. MOS capacitors. At low frequencies, th. interface states can follow th. AC signal and yield excess capacitance and conductance. In addition, th. parallel conductance （G p /ω） versus log（f） curves at various voltages include a peak due to th. presence of interface states. It is observed th.t th. N ss and th.ir time constant （τ） range from 1.23 ×10 12 eV-1 ·cm-2 to 1.47 ×10 12 eV-1 ·cm-2 and from 7.29 ×10-5 s to 1.81 ×10-5s, respectively.

关键词： MOS capacitor admittance measurements interface states

Effective Dielectric Properties of Au-ZnS and Au-ZnO Plasmonics Nanocomposites in th. Terah.rtz Regime

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Ch.nese Ph.sics Letters 2014年第10期31卷 96-99页

作者： A. Zolanvar h. Sadegh. A. Ranjgar Department of Ph.sics Faculty of Science Arak University Arak 8349-8-38156 Iran

Composite materials based on plasmonic nanoparticles allow building metamaterials with.very large effective permittivity （positive or negative）. Moreover, if clustered or combined with.oth.r nanoparticles, it is also possible to generate effective magnetic permeability （positive or negative）, and an ad-h.c design would result in th. generation of double negative materials, and th.refore backward wave propagation. In th.s work, th. optical properties such.as th. effective permittivity, permeability and refractive index of Au-ZnS and Au-ZnO nanocomposites in a broad frequency range are studied. Th. enh.ncement is attributed to energy transfer from ZnS or ZnO to Au followed by a large local electromagnetic field on or near th. surface of th. Au nanoparticles. Local surface plasmon resonance could be th. key＂ reason for th.s enh.ncement. Th. surface plasmon, in response to ch.nges in th. refractive index of th. local environment, also depends on th. type of metal th.ough.th. bulk plasma wavelength.and th. nano-particle compositions and geometry.

关键词： DIELECTRIC properties NANOCOMPOSITE materials SUBMILLIMETER waves PERMITTIVITY measurement SURFACE plasmon resonance ELECTROMAGNETIC fields