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Surface Characterization and Cell Response of binary Ti-Ag Alloys with CP Ti as Material Control

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Journal of Materials Science & Technology 2012年第9期28卷 779-784页

作者： b.b. Zhang K.J. Qiu b.L. Wang L. Li Y.F. Zheng Center for biomedical Materials and Engineering Harbin Engineering University Harbin 150001 China Department of Materials Science and Engineering College of Engineering Peking University Beijing 100871 China

In this study, the surface passive films, dissolution behavior and biocompatibility of Ti-Ag alloys （with 5%, 10% and 20% Ag） were evaluated by X-ray diffraction （XRD） tests, electrochemical corrosion tests, X-ray photoelectron spectroscopy （XPS） tests, dissolution tests and in-vitro cytotoxicity tests. The surface films on the Ti-20Ag alloy are rich in Ti and much deficient in Ag with respect to alloy composition, as identified by XPS. Compared to CP Ti, Ti-SAg and Ti-20Ag alloys show larger impedances and lower capacitances, which can be associated with an increase of the passive layer thickness. Moreover, all Ti-Ag alloys exhibit negligible or low metal release in the test solutions. The in-vitro cytotoxicity results show Ti-Ag alloys seem to be as cytocompatible as CP Ti. From the viewpoint of surface passive film and cytotoxicity, Ti-SAg and Ti-20Ag are considered to be more suitable for dental applications.

关键词： Ti-Ag alloy Surfaces Electrochemical corrosion Cytotoxicity

Audio-frequency heating of particulate magnetic systems

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China Particuology 2007年第1期5卷 84-92页

作者： b.E. Kashevsky I.V. Prokhorov S.b. Kashevsky A.V. Luikov Heat and Mass Transfer Institute Belarus Academy of Sciences P. Brovka str. 15 Minsk 220072 Belarus

This paper presents theoretical and experimental studies on the magnetodynamics and energy dissipation in suspensions of small ferromagnetic particles with magnetic hysteresis and mechanical mobility in an AC magnetic field. Energy absorption by particles suspended in a solid, liquid or gas environment and subjected to high frequency magnetic fields is of great interest for cancer treatment by hyperthermia, chemical technology, biotechnology and smart materials science. Sub-micron needle-like γ-Fe2O3 particles dispersed in liquid were subjected in this study to a 430 Hz magnetic field with an intensity of up to 10^5 A/m. Dynamic magnetization loops were measured in parallel to the energy dissipated in the samples. Combined magnetomechanical dynamics of particle dispersions was simulated by using a chain-of-spheres model allowing for incoherent magnetic field reversal. In liquid dispersions, within the kilohertz frequency range, the mechanical mobility of particles does not interfere with their hysteretic magnetic reversal that makes heat release comparable to that observed with solids; for instance, in the present study using γ-Fe2O3 particles in liquid subjected to 10^4 Hz field exhibited heat release rates from 250 up to 600W oer 1 cm^3 of the dry oarticle content.

关键词： AC magnetic field Particulate materials Audio-frequency heating

Turbulent flow in converging nozzles,part one:boundary layer solution

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Applied Mathematics and Mechanics(English Edition) 2011年第5期32卷 645-662页

作者： R.MADDAHIAN b.FARHANIEH b.FIROOZAbADI Center of Excellence in Energy Conversion School of Mechanical Engineering Sharif University of Technology

The boundary layer integral method is used to investigate the development of the turbulent swirling flow at the entrance region of a conical nozzle. The governing equations in the spherical coordinate system are simplified with the boundary layer as- sumptions and integrated through the boundary layer. The resulting sets of differential equations are then solved by the fourth-order Adams predictor-corrector method. The free vortex and uniform velocity profiles are applied for the tangential and axial velocities at the inlet region, respectively. Due to the lack of experimental data for swirling flows in converging nozzles, the developed model is validated against the numerical simulations. The results of numerical simulations demonstrate the capability of the analytical model in predicting boundary layer parameters such as the boundary layer growth, the shear rate, the boundary layer thickness, and the swirl intensity decay rate for different cone angles. The proposed method introduces a simple and robust procedure to investigate the boundary layer parameters inside the converging geometries.

关键词： swirling flow converging nozzle swirl intensity decay rate boundary layer integral method analytical solution

Microstructural Evolution during Partial Remelting of Al—Si Alloys Containing Different Amounts of Magnesium

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Journal of Materials Science & Technology 2013年第10期29卷 971-978页

作者： A.Abedi M.Shahmiri b.Amir Esgandari b.Nami Department of Mechanical Engineering Shahid Rajaee Teacher Training University (SRTTU) School of Metallurgy and Materials Science Iran University of Science and Technology (IUST)

The effect of magnesium on the microstructures of A356 aluminum alloy in as-cast and semi-solid conditions was investigated. The result showed that magnesium refined the size of primary α（Al） phase and eutectic silicon. Magnesium also modified considerably the eutectic silicon and decreased the size of globular α（Al） solid phase in the semi-solid processed alloy. Coarsening rate of the solid α（Al） phase during partial remelting at semi-solid temperature decreased by adding magnesium, probably due to the decrease of both the solid- liquid interfacial energy and inter-diffusion coefficient of solute atoms.

关键词： Al--Si alloys Magnesium Microstructure Semi-solid processing Coarsening

Negative refractions by triangular lattice sonic crystals in partial band gaps

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Chinese Physics b 2015年第4期24卷 310-321页

作者： S.Alagoz b.b.Alagoz A.Sahin S.Nur Department of Physics Inonu University Department of Electrical and Electronics Engineering Inonu University Vocational School of Health Services Medical Imaging Techniques Inonu University

This study numerically demonstrates the effects of partial band gaps on the negative refraction properties of sonic crystal. The partial band gap appearing at the second band edge leads to the efficient transmissions of scattered wave envelopes in the transverse directions inside triangular lattice sonic crystal, and therefore enhances the refraction property of sonic crystal. Numerical simulation results indicate a diagonal guidance of coupled scattered wave envelopes inside crystal structure at the partial band gap frequencies and then output waves are restored in the vicinity of the output interface of sonic crystal by combining phase coherent scattered waves according to Huygens＇ principles. This mechanism leads to two operations for wavefront engineering： one is spatial wavefront shifting operation and the other is convex-concave wavefront inversion operation. The effects of this mechanism on the negative refraction and wave focalization are investigated by using the finite difference time domain （FDTD） simulations. This study contributes to a better understanding of negative refraction and wave focusing mechanisms at the band edge frequencies, and shows the applications of the slab comer beam splitting and SC-air multilayer acoustic system.

关键词： sonic crystal negative refraction wave focusing partial band gap

Three-degree-of-freedom Parallel Manipulator to Track the Sun for Concentrated Solar Power Systems

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Chinese Journal of Mechanical Engineering 2015年第4期28卷 793-800页

作者： ASHITH SHYAM R b GHOSAL A Robotics and Design Lab Indian Institute of Science

In concentrated solar power（CSP） generating stations, incident solar energy is reflected from a large number of mirrors or heliostats to a faraway receiver. In typical CSP installations, the mirror needs to be moved about two axes independently using two actuators in series with the mirror effectively mounted at a single point. A three degree-of-freedom parallel manipulator, namely the 3-RPS parallel manipulator, is proposed to track the sun. The proposed 3-RPS parallel manipulator supports the load of the mirror, structure and wind loading at three points resulting in less deflection, and thus a much larger mirror can be moved with the required tracking accuracy and without increasing the weight of the support structure. The kinematics equations to determine motion of the actuated prismatic joints in the 3-RPS parallel manipulator such that the sun＇s rays are reflected on to a stationary receiver are developed. Using finite element analysis, it is shown that for same sized mirror, wind loading and maximum deflection requirement, the weight of the support structure is between 15% and 60% less with the 3-RPS parallel manipulator when compared to azimuth-elevation or the target-aligned configurations.

关键词： 3-RPS Parallel manipulator Heliostat Solar tracking

Lanthanide-doped nanoscintillators

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Light(Science & Applications) 2022年第10期11卷 2264-2266页

作者： Jean-Claude Georges bünzli institute of Chemical Sciences and Engineering Swiss Federal Institute of TechnologyLausanne(EPFL)LausanneSwitzerland Department of biomedical Engineering Southern University of Science and Technology(SUSTech)ShenzhenChina

Lanthanide-doped nanoscintillators are taking the lead in several important fields including radiation detection,biomedicine,both at the level of diagnosis and therapy,and information encoding.

关键词： diagnosis Lanthanide ill

Effect of a semi electro-mechanical engine valve on performance and emissions in a single cylinder spark ignited engine

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第2期11卷 106-114页

作者： bülent ZDALYAN Oguzhan DOGAN Department of Automotive Education Karabuk UniversityKarabuk 78050Turkey

In this study, an electro-mechanical valve （EMV） system for the intake valve ofa fottr stroke, single cylinder, overhead valve and spark ignition （SI） engine was designed and constructed. An engine with the EMV system and a standard engine were tested to observe the effects of the EMV on engine performance and emissions at different speeds under full load. The EMV engine showed improved engine power, engine torque and break specific fuel consumption （bSFC）. A 66% decrease in CO emissions was also obtained with the EMV system, but hydrocarbons （HC） and NOx emissions increased by 12% and 13% respectively.

关键词： Semi electro-mechanic Camless engine Electro-mechanic engine valve Engine performance Emissions

Perturbation and variational approach for the equation of state for hard-sphere and Lennard-Jones fluids

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Chinese Physics b 2012年第4期21卷 383-395页

作者： S. b. Khasare Department of Physics Science College Congress Nagar Nagpur India

The present work uses the concept of a scaled particle along with the perturbation and variation approach, to develop an equation of state （EOS） for a mixture of hard sphere （HS）, Lennar-Jones （L J） fluids. A suitable flexible functional form for the radial distribution function G（R） is assumed for the mixture, with R as a variable. The function G（R） has an arbitrary parameter m and a different equation of state can be obtained with a suitable choice of m. For m = 0.75 and m = 0.83 results are close to molecular dynamics （MD） result for pure HS and LJ fluid respectively.

关键词： equation of state Lennard-Jones potential hard-sphere potential liquid mixture com- puter simulation