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Wear Behavior of PTFe–Hydroxyapatite Composite Fabricated by Hot-Press Sintering Process

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Acta metallurgica Sinica(english Letters) 2014年第2期27卷 347-351页

作者： H.R.Zafarani m.Abdi m.e.Bahrololoom Department of materials Science and engineering School of EngineeringShiraz University

In the present work, a new biocompatible composite was fabricated by hot-press sinter-bonding of polytet- rafluoroethylene （PTFe）-hydroxyapatite composite. Furthermore, the wear properties of this composite were studied by computer-controlled pin-on-disk type tribometer in reporting volume loss per distance. The investigation was performed in three different fractions of hydroxyapatite （10, 20 and 30 wt%）. In order to improve the bonding between hydroxyapatite and PTFe, and thus to increase the wear properties of the composite, the effect of adding silane-coupling agent was investigated. Furthermore, to simulate the environment of human body, some of the wear tests were carried out in the ringer＇s solution. It was found that the wear resistance is improved at high load. moreover, an optimum fraction of hydroxyapatite （20 wt%） was found in which the best wear resistance is achieved, especially at dry sliding condition. At last, the roles of the factors such as wear load, ringer＇s solution, and silane-coupling agent are described with respect to their influences on the Lancaster wear coefficient.

关键词： Hydroxyapatite composite Polymers Silane-coupling agent Wear resistance

Prostate-specific antigen （PSA） screening： has the pendulum swung too far？

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Asian Journal of Andrology 2011年第5期13卷 655-656页

作者： Jason m Phillips e David Crawford Department of Urology University of Colorado HealthSciences Center Aurora CO 80045 USA

Prostate-specific antigen （PSA） along with digital rectal exam has been the standard for prostate cancer screening in the United States for the past 20 years.1 During this time period, the improved detection of prostate cancer decreased related mortality more than 30%.2 In fact, metastases and their comorbidities have decreased more than 75% since the early 1990s, resulting in a higher incidence of early organ-confined disease. While it is clear that prostate cancer mortality statistics have improved, it is unclear whether men are overscreened.

关键词： Diseases Phenotypic screening

Analytical solution for laminar flow through leaky tube

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Applied mathematics and mechanics(english edition) 2011年第1期32卷 69-74页

作者： m.GORJI m.ALIPANAH m.SHATeRI e.FARNAD Department of mechanical engineering Babol University of Technology Water and Westwater Company

The laminar flow through a leaky tube is investigated, and the momentum and conservation of energy equations are solved analytically. By using the Hagen-Poiseuille velocity profile and defining unknown functions for the axial and radial velocity compo- nents, the pressure and mass transfer equations are obtained, and their profiles are plotted according to different parameters. The results indicate that the axial velocity, the radial velocity, the mass transfer parameter, and the pressure in the tube decrease as the fluid moves along the tube.

关键词： leaky tube permeability mass transfer laminar flow analytical solution

Inflation in Non-de Sitter Background with Coherent States

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Communications in Theoretical Physics 2016年第3期65卷 308-314页

作者： e.Yusofi m.mohsenzadeh m.R.Tanhayi Department of Physics Ayatollah Amoli BranchIslamic Azad University Department of Physics Qom BranchIslamic Azad University Department of Physics Islamic Azad UniversityCentral Tehran Branch

We use the excited coherent states built over the initial non-de Sitter modes,to study the modification of spectra of primordial scalar ***-de Sitter modes are actually the asymptotic solution of the inflaton field equation[*** energy Phys.09（2014） 020].We build excited coherent states over the non-de Sitter modes and despite the Jack of interactions in the Lagrangian,we find a non-zero one-point *** is shown that the primordial non-Gaussianity resulting from.e.cited-de Sitter modes depend both of time and background *** is very tiny of order（≤10^-24）,at the Planck initial fixed time that confirmed by resent observations for single field inflation but it grows in the present ***,our results at the leading order are similar to what obtained with general initial states and in the dS limit leads to standard results[***.1202（2012） 005].We will show that the non-dS modes and its resulting spectrum are more usable for far past time limit.

关键词： inflation initial states planck time background space-time

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自然保护生物学

Use of mesophilic and thermophilic bacteria for the improvement of copper extraction from a low-grade ore

1991年

作者： michael e.·索莱(m.e. Soule ) B.A.·威尔考克斯(Bruce A. Wilcox)

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International Journal of minerals,metallurgy and materials 2011年第2期18卷 138-143页

作者： e.Darezereshki m.Schaffie m.Lotfalian S.A.Seiedbaghery m. Ranjbar Department of mineral Processing engineering Bahonar University energy and environmental engineering Research Center (eeRC) Bahonar University Department of Chemical engineering Bahonar University Industrial mining Research Center (ImRC) Bahonar University Hydrometallurgy Research Unit R & D Center Sarcheshmeh Copper Complex

Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leaching of the ore. Sulfuric acid solution with a flow rate of 3.12 L·m-2·h-1 and pH 1.5 passed through each column continuously for 90 d. In the first and the second column, bioleaching was performed without agglomeration of the ore and on the agglomerated ore, respectively. 28wt% of the copper was extracted in the first column after 40 d, while this figure was 38wt% in the second column. After 90 d, however, the overall extractions were almost the same for both of them. Bioleaching with mesophilic bacteria was performed in the third column without agglomeration of the ore and in the fourth column on the agglomerated ore. After 40 d, copper extractions in the third and the fourth columns were 62wt% and 70wt%, respectively. Copper extractions were 75wt% for both the columns after 90 d. For the last column, bioleaching was performed with moderate thermophilic bacteria and agglomerated ore. Copper extractions were 80wt% and 85wt% after 40 and 90 d, respectively. It was concluded that crushing and agglomeration of the ore using bacteria could enhance the copper extraction considerably.

关键词： bioleaching mesophilic bacteria thermopilic bacteria copper extraction agglomeration.

melting heat transfer effects on stagnation point flow of micropolar fluid saturated in porous medium with internal heat generation(absorption)

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Applied mathematics and mechanics(english edition) 2014年第8期35卷 979-992页

作者： m.A.A.mAHmOUD S.e.WAHeeD Department of mathematics Faculty of ScienceBenha University 13518BenhaEgypt Department of mathematics and Statistic Faculty of ScienceTaif University 21974TaifKingdom of Saudi Arabia

The effect of melting heat transfer on the two dimensional boundary layer flow of a micropolar fluid near a stagnation point em.e.ded in a porous medium in the presence of internal heat generation/absorption is investigated. The governing non-linear partial differential equations describing the problem are reduced to a system of non-linear ordinary differential equations using similarity transformations solved numerically using the Chebyshev spectral method. Numerical results for velocity, angular velocity and tem.e.ature profiles are shown graphically and discussed for different values of the inverse Darcy num.e., the heat generation/absorption parameter, and the melting parameter. The effects of the pertinent parameters on the local skin-friction coefficient, the wall couple stress, and the local Nusselt num.e. are tabulated and discussed. The results show that the inverse Darcy num.e. has the effect of enhancing both velocity and tem.e.ature and suppressing angular velocity. It is also found that the local skin-friction coefficient decreases, while the local Nusselt num.e. increases as the melting parameter increases.

关键词： melting effect stagnation point micropolar fluid porous medium heat generation (absorption)

Variable fluid properties and thermal radiation effects on flow and heat transfer in micropolar fluid film past moving permeable infinite flat plate with slip velocity

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Applied mathematics and mechanics(english edition) 2012年第5期33卷 663-678页

作者： m.A.A.mAHmOUD S.e.WAHeeD Department of mathematics Faculty of ScienceBenha UniversityBenha 13518Egypt

This work deals with the influence of thermal radiation on the problem of the mixed convection thin film flow and heat transfer of a micropolar fluid past a moving infinite vertical porous flat plate with a slip velocity. The fluid viscosity and the thermal conductivity are assumed to be the functions of tem.e.ature. The equations governing the flow are solved numerically by the Chebyshev spectral method for some representative value of various parameters. In comparison with the previously published work, the excellent agreement is shown. The effects of various parameters on the velocity, the microrotation velocity, and the tem.e.ature profiles, as well as the skin-friction coefficient and the Nusselt num.e., are plotted and discussed.

关键词： micropolar fluid thin film slip velocity variable fluid properties thermalradiation Chebyshev spectral method

Photoconductive devices for terahertz pulsed spectroscopy:a review[Invited]

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Photonics Research 2016年第3期4卷 36-42页

作者： e.Castro-Camus m.Alfaro Centro de Investigaciones en Optica A.C. Departamento de matematicas y Fisica Centro de Ciencias BasicasUniversidad Autonoma de Aguascalientes

Photoconductive switches were the key components that allowed the generation and detection of coherent broadband electromagnetic pulses at terahertz frequencies, opening the possibility for performing spectroscopy and,therefore, measuring complex dielectric properties of materials in this band, which was mostly unexplored. In this paper, we present a brief introduction to the operation principles of these devices. Subsequently, we present a review of the current state-of-the-art in this field and discuss the challenges to be faced in future development of these devices.

关键词： As Ga THz Photoconductive devices for terahertz pulsed spectroscopy:a review[Invited