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Brownian motion and thermophoresis effects on unsteady stagnation point flow of Eyring-Powell nanofluid: a Galerkin approach

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Communications in Theoretical Physics 2020年第12期72卷 71-82页

作者： z H Khan m Usman T zubair m Hamid R U Haq State Key Laboratory of Hydraulics and mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China BIC-ESAT College of EngineeringPeking UniversityBeijing 100871China State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering SciencePeking UniversityBeijing 100871China Institute of Ocean Research Peking UniversityBeijing 100871China School of mathematical Sciences Peking UniversityBeijing 100871China Department of mechanics and Engineering Science Fudan UniversityShanghai 200433China Department of Electrical Engineering Bahria UniversityIslamabad CampusIslamabad 44000Pakistan

This article concerns the analysis of an unsteady stagnation point flow of Eyring–Powell nanofluid over a stretching *** influence of thermophoresis and Brownian motion is also considered in transport *** nonlinear ODE set is obtained from the governing nonlinear equations via suitable *** numerical experiments are performed using the Galerkin scheme.A tabular form comparison analysis of outcomes attained via the Galerkin approach and numerical scheme(RK-4)is available to show the credibility of the Galerkin *** numerical exploration is carried out for various governing parameters,namely,Brownian motion,steadiness,thermophoresis,stretching ratio,velocity slip,concentration slip,thermal slip,and fluid parameters,and Hartmann,Prandtl and Schmidt *** velocity of fluid enhances with an increase in fluid and magnetic parameters for the case of opposing,but the behavior is reversed for assisting *** Brownian motion and thermophoresis parameters cause an increase in temperature for both cases(assisting and opposing).The Brownian motion parameter provides a drop-in concentration while an increase is noticed for the thermophoresis *** the outcomes and the behavior of emerging parameters are illustrated *** comparison analysis and graphical plots endorse the appropriateness of the Galerkin *** is concluded that said method could be extended to other problems of a complex nature.

关键词： Eyring-Powell fluid stagnation point flow Brownian motion and thermophoresis Galerkin method

Synergetic deformation mechanisms in an mg-zn-Y-zr alloy with intragranular LPSO structures

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Journal of magnesium and Alloys 2023年第5期11卷 1754-1768页

作者： z.z.Peng X.H.Shao z.m.Liang D.L.Wang L.W.Wang X.L.ma Hebei Key Laboratory of material Near-Net Forming Technology School of Materials Science and EngineeringHebei University of Science and TechnologyShijiazhuang 050018China Shenyang National Laboratory for materials Science Institute of Metal ResearchChinese Academy of Sciences72 Whenua RoadShenyang 110016China

Deformation kink is one of the important strengthening mechanisms of the long-period-stacking-ordered(LPSO)phase containing magnesium(mg)alloys,while the deformation twin is generally *** optimize the mechanical properties of LPSO containing mg alloy by simultaneously exciting kink and twin,we successfully prepared the mg-zn-Y-zr alloy featuring intragranular LPSO phase and free grain boundary LPSO phase by *** unraveled the corresponding strengthening and toughening mechanisms through transmission electron microscopy characterization and theoretical *** high strength and good plasticity of the homogenized alloy benefit from the synergistic deformation mechanism of multiple kinking and twining in the *** the activation of kinking and twinning depends on the thicknesses of LPSO lamellae and their relative *** results may shed light on optimizing the design of mg alloys regulating the microstructure of LPSO phases.

关键词： mg alloy LPSO distribution Kink Twin Transmission electron microscopy

Effect of Rotation Rate on microstructures and mechanical Properties of FSW mg-zn-Y-zr Alloy Joints

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Journal of materials Science & Technology 2011年第12期27卷 1157-1164页

作者： G.m. Xie z.Y. ma z.A. Luo P. Xue G.D. Wang The State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110819 China Shenyang National Laboratory for materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China

Friction stir welding （FSW） of mg-zn-Y-zr plates with 6 mm in thickness was successfully carried out under a wide range of rotation rates of 600-1200 r/rain with a constant traverse speed of 100 mm/min. After FSW, the coarse grains in the parent material （Pm） were changed into fine equiaxed recrystallized grains at the＇nugget zone （Nz）. Furthermore, the coarse mg-zn-Y particles （W-phase） were broken up and dispersed homogenously into the mg matrix. With increasing rotation rates, the size of the W-phase particles at the Nz significantly decreased, but the recrystallized grain size tended to increase. The hardness values of the Nzs for all the FSW joints were higher than those of the Pm, and the lowest hardness values were detected in the heat affected zone （HAz）. The fracture occurred in the thermo-mechanical affected zone （TmAz） on the advancing side for all the FSW joints in the tensile test, due to the incompatibility of the plastic deformation between the Nz and TmAz caused by remarkably different orientation of grains and W-phase particles. The strength of FEW ioint reaches 90% of that of its Pm

关键词： Friction stir welding magnesium alloys microstructure mechanical property

Simulation of the spatio-temporal evolution of the electron energy distribution function in a pulsed hollow-cathode discharge

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Plasma Science and Technology 2023年第3期25卷 87-94页

作者： N A ASHURBEKOV K O ImINOV K m RABADANOV G S SHAKHSINOV m z zAKARYAEVA m B KURBANGADzHIEVA Dagestan State University Department of Physics Harbin Institute of Technology Institute of Physics Dagestan Federal Research CenterRussian Academy of Sciences

This article presents the 2D simulation results of a nanosecond pulsed hollow cathode discharge obtained through a combination of fluid and kinetic *** spatio-temporal evolution of the electron energy distribution function(EEDF)of the plasma column and electrical characteristics of the nanosecond pulsed hollow cathode discharge at a gas pressure of 5 Torr are *** results show that the discharge development starts with the formation of an ionization front at the anode *** ionization front splits into two parts in the cathode cavity while propagating along its lateral *** ionization front formation leads to an increase in the fast isotropic EEDF component at its front,as well as in the anisotropic EEDF *** accelerated electrons enter the cathode cavity,which significantly contributes to the formation of the highenergy EEDF component and EEDF anisotropy.

关键词： pulsed nanosecond discharge electron energy distribution fuinction hollow cathode electron kinetics gas discharge

Coherence of SH-waves near a semi-circular inclusion-the role of interference and standing waves

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Earthquake Engineering and Engineering Vibration 2021年第3期20卷 535-552页

作者： z.Tokmechi R.S.Jalali m.D.Trifunac m.I.Todorovska Department of Civil Engineering Faculty of EngineeringUniversity of GuilanP.O.Box 3756RashtIran Department of Civil Engineering University of Southern CaliforniaLos AngelesCalifornia 90089USA Department of Civil Engineering Tianjin UniversityTianjin 300350China

We present examples of a controlled numerical experiment that contribute towards understanding of the physical phenomena that lead to the reduction of coherency of strong earthquake ground *** show examples for separation distance of 100 m between the two points on the ground surface,which is in the range of engineering *** examples illustrate the consequences of:(a)standing waves that result from interference of the incident and reflected waves from a near vertical contrast in material properties,(b)standing waves within a concave inhomogeneity(a semi-circular valley in our examples),and(c)smaller motions in the diffraction zone,behind the *** show that it is possible to reduce coherency,to the extent observed for recorded strong earthquake ground motion,even by a single inclusion in a half space,for incident ground motion that is *** also illustrate the combined effects of geometric spreading and finite fault width,superimposed on the otherwise dominating effects caused by *** examples show reduction of coherence for specific angles of incident waves,while,for other angles of incidence,the coherence remains essentially equal to one.

关键词： coherence of strong motion coherence in the presence of standing waves coherence caused by interference reduction of coherence for radiation from large faults

The η-Pairing Superconductivity in Spin-Density Wave Background

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Chinese Physics Letters 1993年第10期10卷 616-619页

作者： X.m.Qiu z.J.Wang Southwestern Institute of Physics P.O.Box 432Chengdu 610041

In this letter,we propose a modified attractive Hubbard model at half filling that can exhibit sup er con ductivity through η-pairing *** in spin-density wave representation and derive a concise relationship between the energy disparity and the single-particle energy *** relationship,in the two limits of U,clearly shows that the system does not display sup er con ductivity for very low doping concen・*** *** s up ere on ductivity when the doping concentration exceeds a certain critical *** conclusion is in quaJitative agreement with the familiar experiments on higli-T_(c) supcrconductivity.

关键词： spectrum value doping

Study of Bacterial Samples Using Laser Induced Breakdown Spectroscopy

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Plasma Science and Technology 2014年第12期16卷 1141-1146页

作者： W A FAROOQ m ATIF W TAWFIK m S ALSALHI z A ALAHmED m SARFRAz J P SINGH Physics and Astronomy Department College of ScienceKing Saud UniversityRiyadh 11451Saudi Arabia National Institute of Laser and Optronics NiloreIslamabadPakistan National Institute of Laser Enhanced Sciences NILES Department of Environmental ApplicationsCairo UniversityCairoEgypt Sustainable Energy Technologies Centre King Saud UniversityRiyadhSaudi Arabia Institute for Clean Energy Technology Mississippi State UniversityStarkvilleMS 39759USA

Laser-induced breakdown spectroscopy （LIBS） technique has been applied to inves- tigate two different types of bacteria, Escherichia coli （B1） and micrococcus luteus （B2） deposited on glass slides using Spectrolaser 7000. LIBS spectra were analyzed using spectrolaser software. LIBS spectrum of glass substrate was compared with bacteria spectra. Ca, mg, Na, K, P, S, C1, Fe, A1, mn, Cu, C, H and CN-band appeared in bacterial samples in air. Two carbon lines at 193.02 nm, 247.88 nm and one hydrogen line at 656.28 nm with intensity ratios of 1.9, 1.83 and 1.53 appeared in bacterial samples B1 and B2 respectively. Carbon and hydrogen are the important components of the bio-samples like bacteria and other cancer cells. Investigation on LIBS spectra of the samples in He and Ar atmospheres is also presented. Ni lines appeared only in B2 sample in Ar atmosphere. From the present experimental results we are able to show that LIBS technique has a potential in the identification and discrimination of different types of bacteria.

关键词： laser induced breakdown bacteria bio-samples and carbon lines

Investigations into the Anti-Felting Properties of Sputtered Wool Using Plasma Treatment

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Plasma Science and Technology 2013年第1期15卷 37-42页

作者： S. m. BORGHEI S. SHAHIDI m. GHORANNEVISS z. ABDOLAHI Department of Physics Karaj Branch Islamic Azad University Department of Textiles Faculty of Engineering Arak Branch Islamic Azad University Plasma Physics Research Center Science and Research Branch Islamic Azad University

In this research the effects of mordant and plasma sputtering treatments on the crystallinity and morphological properties of wool fabrics were investigated. The felting behavior of the treated samples was also studied. We used madder as a natural dye and copper sulfate as a metal mordant. We also used copper as the electrode material in a DC magnetron plasma sputtering device. The anti-felting properties of the wool samples before and after dying was studied, and it was shown that the shrink resistance and anti-felting behavior of the wool had been significantly improved by the plasma sputtering treatment. In addition, the percentage of crystallinity and the size of the crystals were investigated using an X-ray diffractometer, and a scanning electron microscope was used for morphological analysis. The amount of copper particles on the surface of the mordanted and sputtered fabrics was studied using the energy dispersive X- ray （EDX） method, and the hydrophobic properties of the samples were examined using the water drop test. The results show that with plasma sputtering treatment, the hydrophobic properties of the surface of wool become super hydrophobic.

关键词： anti-felting wool plasma mordant sputtering

A mONTE CARLO SImULATION OF SECONDARY ELECTRON AND BACKSCATTERED ELECTRON ImAGES IN SCANNING ELECTRON mICROSCOPY

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Acta metallurgica Sinica(English Letters) 2005年第3期18卷 351-355页

作者： H.m.Li z.J.Ding HefeiNationalLaboratoryforPhysicalSciencesatmicroscaleandDepartmentofPhysics UniversityofScienceandTechnologyofChinaHefei230026China

A new parallel monte Carlo simulation method of secondary electron (SE) and back scattered electron images (BSE) of scanning electron microscopy (SEm) for a com plex geometric structure has been developed. This paper describes briefly the si mulation method and the modification to the conventional sampling method for the step length. Example simulation results have been obtained for several artifici al structures.

关键词： monte Carlo SEm secondary electrons backscattered electrons,