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Magnetohydrodynamic approach of non-Newtonian blood flow with magnetic particles in stenosed artery

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Applied Mathematics and Mechanics(English Edition) 2017年第3期38卷 379-392页

作者： I. A. MIRZAt M. ABDULHAMEED S. SHAFIE Abdus Salam School of Mathematical Sciences Government College University Lahore 54000 Pakistan School of Science and Technology Federal Polytechnic P. M. B. Bauchi 0231 Nigeria Department of Mathematical Sciences Faculty of Science Universiti Teknologi Skudai 81310 Malaysia

The non-Newtonian blood flow, together with magnetic particles in a stenosed artery, is studied using a magneto-hydrodynamic approach. The wall slip condition is also considered. Approximate solutions are obtained in series forms under the assumption that the Womersley frequency parameter has small values. Using an integral transform method, analytical solutions for any values of the Womersley parameter are *** simulations are performed using MATHCAD to study the influence of stenosis and magnetic field on the flow parameters. When entering the stenosed area, blood velocity increases slightly, but increases considerably and reaches its maximum value in the stenosis throat. It is concluded that the magnitude of axial velocity varies considerably when the applied magnetic field is strong. The magnitude of maximum fluid velocity is high in the case of weak magnetic fields. This is due to the Lorentz's force that opposes motion of an electrically conducting fluid. The effect of externally transverse magnetic field is to decelerate the flow of blood. The shear stress consistently decreases in the presence of a magnetic field with increasing intensity.

关键词： Bingham plastic fluid, magnetic particle, blood flow, magnetohydrodynam-ics, artery stenosis

Preparation and characterization of Fe_(3)O_(4)/Au composite particles

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Science China Chemistry 2004年第2期47卷 152-158页

作者： CUI Yali HUI Wenli WANG Huirong WANG Lijun CHEN Chao Biochip Research and Development Center Northwest University National Engineering Research Center for Miniaturized Detection System Xi'an 710069 China Biochip Research and Development Center Northwest University National Engineering Research Center for Miniaturized Detection System Xi'an 710069 China Biochip Research and Development Center Northwest University National Engineering Research Center for Miniaturized Detection System Xi'an 710069 China Biochip Research and Development Center Northwest University National Engineering Research Center for Miniaturized Detection System Xi'an 710069 China Biochip Research and Development Center Northwest University National Engineering Research Center for Miniaturized Detection System Xi'an 710069 China

Using Fe3O4 nano-particles as seeds, a new type of Fe3O4/Au composite particles with core/shell structure and diameter of about 170 nm was prepared by reduction of Au3+ with hydroxylamine in an aqueous solution. particle size analyzer and transmission electron micro-scope were used to analyze the size distribution and microstructure of the particles in different conditions. The result showed that the magnetically responsive property and suspension stability of Fe3O4 seeds as well as reduction conditions of Au3+ to Au0 are the main factors which are crucial for obtaining a colloid of the Fe3O4/Au composite particles with uniform particle dispersion, excellent stability, homogeneity in particle sizes, and effective response to an external magnet in aqueous suspension solutions. UV-Vis analysis revealed that there is a characteristic peak of Fe3O4/Au fluid. For particles with d(0.5)=168 nm, the lmax is 625 nm.

关键词： Fe3O4/Au, core/shell structure, composite particle, preparation, properties.

Nanometer structure and conductor mechanism of polymer modified by metal ion implantation

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Science China(Technological Sciences) 2001年第5期44卷 493-498页

作者：吴瑜光张通和张燕文张荟星张孝吉周固 Key Laboratory for Radiation Beam Technology & Material Modification in University Institute of Low Energy Nuclear Physics Beijing Normal University Beijing Radiation Center Beijing 100875 China

Polyethylene terephthalate (PET) has been modified by Ag, Ti, Cu and Si ion implanta-tion with a dose ranging from 1 × l016 to 2 x 1017 ions/cm2 using a metal vapor vacuum arc (MEVVA)source. The electrical properties of PET have been improved by metal ion implantation. The resistivityof implanted PET decreased obviously with an increase in ion dose. The results show that the conduc-tive behavior of a metal ion implanted sample is different from Si-implantation samples. In order to un-derstant the mechanism of electrical conduction, the structures of implanted layer were observed in de-tail by XRD and TEM. The nano carbon particles were dispersed in implanted PET. The nano metallicparticles were built up in metallic ion implanted layers with dose range from 1 × 1016 to 1 x 1017 ions/cm2. The nanometer metal net structure was formed in implanted layer when a dose of 2 x 1017ions/cm2 is reached. Anomalous fractal growths were observed. These surface structure changes revealedconducting mechanism evolution, lt is believed that the change would result in an improvement of theconductive properties. The conducting mechanism will be changed with increasing metal ion dose.

关键词： metal ion implantation, nanometer particle, resistivity, conducting mechanism.

Encapsulation of inorganic particles by dispersion polymerization through ultrasonic irradiation

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Science China Chemistry 2005年第6期48卷 545-552页

作者： ZHANG Kai1,2, FU Qiang1, HUANG Yuhong2 & ZHOU Dehui2 1. College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China 2. Institute of Structure Mechanics, China Academy of Engineering Physics, Mianyang 621900, China College of Polymer Science and Engineering Sichuan University Chengdu China Institute of Structure Mechanics China Academy of Engineering Physics Mianyang China

The nano-silica/polystyrene composite particles were prepared and characterized according to the following steps. First, the nano-silica particles were pretreated with surfactants under ultrasonic field. Second, the dispersion polymerization of styrene in a water/ethanol (1/6, weight ratio) medium, with poly(N-vinyl pyrrolidone) (PVP) as stabilizer and 2,2’-azobisizobu- tyronitrile (AIBN) as initiator in the presence of nano-silica particles was initiated with N2 purging through ultrasonic irradiation by taking its advantages of multieffect, i.e. dispersion, crushing, activation, and initiation. Finally, the polymerization kinetics characteristics were studied, and the encapsulation of composite particles was investigated with optical microscope, SEM, TEM, FTIR, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

关键词： composite particle, dispersion polymerization, ultrasonic irradiation.

Thermocapillary motion of deformable fluid particles in tubes

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Science China Mathematics 2002年第10期45卷 1335-1350页

作者：陈晋南 Sch. of Chem. Eng. and Mat. Science Beijing Institute of Technology Beijing 100081 China

The boundary integral technique is used to study the effect of deformation on the steady,creeping, thermocapillary migration of a fluid particle under conditions of axisymmetry, negligiblethermal convection and an insulated tube wall. The spherical radius of the fluid particle (i.e. theradius as if the particle were a sphere, a '= (3Vp'/4π)1/3, Vp'is the particle volume) and that ofthe tube are denoted, respectively, by a'and b'. For small capillary number Ca = 0.05, only for alarge fluid particle (a'/b'= 0.8) is deformation significant. For a'/b'= 0.8, hydrodynamic stressessqueeze the particle, reduce the interaction of the particle with the wall and thereby increase theterminal velocity. For small particles a'/b'＜ 0.8 and Ca = 0.05 the fluid particles translate asspheres, due to the fact that the fluid particleis too far away from the wall to be subject to distend-ing hydrodynamic stresses. The deformable particle moves faster than a spherical one in thethermocapillary migration. The increase in velocity with capillary number is larger for thermocapil-lary motion than for buoyancy.

关键词： two phase flow, fluid particle, deformable, thermocapillary migration.