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Transporting droplets through surface anisotropy

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Microsystems & Nanoengineering 2015年第1期1卷 74-81页

作者： Hal R.Holmes Karl f.böhringer Department of bioengineering University of WashingtonSeattleWA 98195USA Department of Electrical Engineering University of WashingtonSeattleWA 98195USA

This review article examines digital microfluidic systems that manipulate droplets through surface *** systems are categorized as surface tension driven or contact line *** tension driven systems include electrowetting on dielectric,Marangoni flow on microheater arrays,and chemical gradient surfaces,whereas contact line driven systems include anisotropic ratchet conveyors,nanostructured Parylene ratchets,and tilted pillar *** article describes the operating principles and outlines the fabrication procedures for each *** also present new equations that unify several previous models of contact line driven *** strengths and weaknesses of each system are compared,with a focus on their ability to perform the generation,switching,fusion,and fission of ***,we discuss current and potential future applications of these systems.

关键词： droplets digital microfluidics electrowetting thermocapillary forces contact line oscillation

Control of purity and entanglement for two spatially two-separated qubits via phase damping

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Chinese Physics b 2012年第10期21卷 115-121页

作者： A.S.f.Obada H.A.Hessian A.b.A.Mohamed M.Hashem faculty of Science Al-Azhar UniversityNasr CityCairoEgypt faculty of Science Assiut UniversityAssiutEgypt faculty of Science Al-Baha UniversityAl-BahaSaudi Arabia Al-Aflaj Community College Salman Bin Abdulaziz University Al-AflajSaudi Arabia

Control of purity and entanglement of two two-qubits dispersively coupled to a field with a reservoir are *** the qubits are entangled,while the field is either in a coherent state or a statistical mixture of two coherent *** an alternative entanglement measure we calculate the negativity of the eigenvalues of the partially transposed density matrix.A measure related to the mutual entropy,namely the index of entropy,is employed to measure the *** results agree well with the *** is found that the entanglement and purity have strong sensitivity to phase *** asymptotic behaviour of the states of the field,the two two-qubits,and the total system fall into mixed states.

关键词： entanglement phase damping purity separated qubits

Cattaneo-Christov heat flux model for third-grade fluid flow towards exponentially stretching sheet

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Applied Mathematics and Mechanics(English Edition) 2016年第6期37卷 761-768页

作者： S.A.SHEHZAD f.M.AbbASI T.HAYAT b.AHMAD Department of Mathematics Comsats Institute of Information TechnologySahiwal 57000Pakistan Department of Mathematics Comsats Institute of Information TechnologyIslamabad 44000Pakistan Department of Mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan NAAM Research Group Faculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia

The Cattaneo-Christov heat flux in the two-dimensional （2D） flow of a third- grade fluid towards an exponentially stretching sheet is investigated. The energy equation is considered through thermal relaxation. Similarity transformations are accounted to obtain the ordinary differential systems. The converted non-dimensional equations are solved for the series solutions. The convergence analysis of the computed solutions is reported. The graphical results of the velocity and temperature profiles are plotted and elaborated in detail. The results show that the thermal relaxation enhances the temper- ature gradient while reduces the temperature profile.

关键词： steady flow third-grade fluid Cattaneo-Christov heat flux exponentiallystretching sheet

Active vibration control of functionally graded beams with piezoelectric layers based on higher order shear deformation theory

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Earthquake Engineering and Engineering Vibration 2016年第4期15卷 611-620页

作者： K. bendine f.b. boukhoulda M.Nouarit Z. Satla Mechanics of Structures and Solids Laboratory Department of Mechanics Faculty of technology Djillali Liabes University of Sidi Bel-Abbes Algeria University of Lorraine Laboratoire d'Energetique et de Mecanique Theorique et Appliquee LEMTA CNRS-UMR 7563 Mines Nancy Nancy 88100 France

This paper reports on a study of active vibration control of functionally graded beams with upper and lower surface-bonded piezoelectric layers. The model is based on higher-order shear deformation theory and implemented using the finite element method （fEM）. The proprieties of the functionally graded beam （fGb） are graded along the thickness direction. The piezoelectric actuator provides a damping effect on the fGb by means of a velocity feedback control algorithm. A Matlab program has been developed for the fGb model and compared with ANSYS APDL. Using Newmark＇s method numerical solutions are obtained for the dynamic equations of fGb with piezoelectric layers. Numerical results show the effects of the constituent volume fraction and the influence the feedback control gain on the frequency and dynamic response of fGbs.

关键词： beams piezoelectric finite element method functionally graded materials vibration control

Structural evolution of Al–8%Si hypoeutectic alloy by ultrasonic processing

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Journal of Materials Science & Technology 2017年第11期33卷 1235-1239页

作者： J.Y.Wang b.J.Wang L.f.Huang Department of Applied Physics Northwestern Polytechnical University Xi'an 710072 China

High intensity power ultrasound was respectively introduced into three different solidification stages of Al–8%Si hypoeutectic alloy, including the fully liquid state before nucleation, the nucleation and growth process of primary α（Al） phase and L →（Al）＋（Si） eutectic transformation period. It is found that both the primary α（Al） phase and（Al ＋ Si） eutectic structure were refined by different degrees with various growth morphologies depending on the ultrasonic treatment stage. based on the experimental results,the cavitation-induced nucleation due to the high undercooling caused by the collapse of tiny cavities was proposed as the major reason for refining the primary α（Al） phase. Meanwhile, obvious eutectic morphological change was observed only when ultrasound was directly introduced in the eutectic transformation stage, in which typical divorced eutectics and（Al ＋ Si） eutectic cells with symmetrical flower shape were formed at the top of the alloy sample. The introduction of ultrasound in each solidification stage also improves the yield strength of Al–8% Si alloy to a diverse extent.

关键词： Solidification Microstructure Metals and alloys Power ultrasound Refinement

Research on the Heat-Conduction Enhancement for Liquid with Nano-Particle Suspensions

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Journal of Thermal Science 2002年第3期11卷 214-219页

作者： b.X.Wang H.Li X.f.Peng Department of Thermal Engineering Tsinghua University Beijing P.R. China

by measuring the effective thermal conductivity, taking photos of the distribution of the nano-particles in the fluids and photos that reflect the interfacial phenomena between nano-particles and fluids, we try to exp... 详细信息

关键词： Nano-particle suspension effective thermal conductivity brownian motion affinity heat-conduction enhancement.

Neumann boundary Conditions Inhibiting SSb in Coleman-Weinberg Mechanism

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Communications in Theoretical Physics 2010年第12期54卷 1071-1074页

作者： f.N.fagundes R.O.francisco b.b.Dilem J.A.Nogueira Universidade federal do Espírito Santo

In this work we show that homogeneous Neumann boundary conditions inhibit the Coleman-Weinberg mechanism for spontaneous symmetry breaking in the scalar electrodynamics if the length of the finite region is small enou... 详细信息

关键词： scalar electrodynamics Neumann boundary conditions spontaneous symmetry breaking

Tuning the fields focused by a high NA lens using spirally polarized beams(Invited Paper)

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Chinese Optics Letters 2017年第3期15卷 51-54页

作者： f.Wackenhut b.Zobiak A.J.Meixner A.V.failla Eberhard Karls University Tübingen Institute of Physical and Theoretical Chemistry University Medical Center Hamburg-Eppendorf UKE Microscopy Imaging Facility

We show the power of spirally polarized doughnut beams as a tool for tuning the field distribution in the focus of a high numerical aperture （NA） lens. Different and relevant states of polarization as well as field distributions can be created by the simple turning of a λ/2 retardation wave plate placed in the excitation path of a micro- scope. The realization of such a versatile excitation source can provide an essential tool for nanotechnology investigations and biomedical experiments.

关键词： Tuning the fields focused by a high NA lens using spirally polarized beams high

A computational study of the role of particle size standard deviation on the collision frequency in differential settling

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International Journal of Sediment Research 2013年第1期28卷 34-45页

作者： C.HEILIGER N.b.KAYE f.Y.TESTIK Civil Engineering Clemson UniversityClemsonSC29634USA

The results of a simple computational model for differential settling are presented illustrating the significant role that particle size distribution plays in collision frequency and sedimentation rate of particles in a quiescent environment. The model tracks a large number of particles（order 10;） with log-normally distributed diameters,as they settle at their Stokes settling *** collisions are detected and result in larger particles that fall more rapidly.A number of simplifying assumptions are made in the model in order to avoid empirical correlations for phenomena such as collision efficiency and particle *** simplifying assumptions were needed to isolate and quantify the role of the particle size *** concentration profiles indicate that,even in the absence of collisions, the standard deviation（σ;） of the particle size strongly influences the bulk mass settling rate as,for largerσ;, more mass is concentrated in larger,faster falling *** collision frequency is also a strong function ofσ;. for a given mass concentration the collision frequency first increases linearly with increasingσ;as greater variation in particle size leads to greater variation in particle velocity,and shorter times for particles to catch each *** largerσ;more mass is concentrated in larger particles,so,for a given mass concentration,there are fewer particles per unit volume,increasing the mean distance between the particles and reducing the collision *** implications of these results for sedimentation measurement using optical attenuation techniques are discussed.

关键词： Settling Sediment size distribution Sediment collision frequency Coefficient of variation