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Plasma spray forming of tungsten coatings on copper electrodes

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中国有色金属学会会刊：英文版 2004年第5期14卷 835-839页

作者：蒋显亮 F.Gitzhofer m.i.Boulos School of materials Science and Engineering Central South University Changsha 410083 China Plasma Technology Research Center University of Sherbrooke Sherbrooke J1K 2R1 Canada

Both direct current dc plasma and radio frequency induction plasma were used to deposit tungsten coatings on copper electrodes. Fine tungsten powder with mean particle size of 5 μm and coarse tungsten powder with particle size in the range from 45 μm to 75 μm were used as plasma spray feedstock. it is found that dc plasma is only applicable to spray the fine tungsten powder and induction plasma can be used to spray both the coarse powder and the fine powder. The tungsten coating deposited by the induction plasma spraying of the coarse powder is extremely dense. Such a coating with an interlocking structure and an integral interface with the copper substrate demonstrates high cohesion strength and adhesion strength.

关键词：等离子喷涂钨铜电解工艺联锁结构金属

Electroanalytical tools to investigate the divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions in non-aqueous medium

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Journal of Rare Earths 2012年第4期30卷 392-396页

作者： Jignasu P mehta Himanshu m Pandya Kahan i Pandya Department of Chemistry DST-FIST sponsored Department Mahatma Gandhi Campus Bhavnagar University

The divalent state of Ln（iii） ions has attracted much interest because of their ability to serve isomorphously in many biological system of divalent Ca（ii） ion. Therefore, present paper deals with the study of divalent state of Eu（iii） and Nd（iii） ions in non-aqueous medium. in present study, cyclic voltammetry and chronopotentiometry were utilized to establish the divalent state of Eu（iii） and Nd（iii） ions. The cyclic voltammetric technique showed two-step reduction process at cathode for both Ln（iii） ions under specified experimental conditions and chronopotentiometric method also showed two different transition times （r）. Looking to the shape of cyclic voltammogram we calculated het- erogeneous forward rate constant （K^fh, cm/s） and diffusion coefficient （D, cm2/s） for both ions, which suggested that sweep rate had great ef- fect on the shape of cyclic voltammogram of Eu（iii） and Nd（iii） ions. The result of chronopotentiometry also suggested that stable divalent states of Eu（iii） and Nd（iii） ions existed with chronopotentiogram with two distinct transition times. The diffusion coefficients （D, cm2/s） were calculated from Sand equation. The diffusion coefficients of both techniques were compared and the results suggested that the system at electrode surface was changing from being reversible to irreversible.

关键词： Eu(ili) and Nd(iii) ions non-aqueous medium cyclic-voltammetry chronopotentiomentry rare earths

Simulation and Analysis of multisoliton Generation Using a PANDA Ring Resonator System

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Chinese Physics Letters 2011年第10期28卷 95-98页

作者： i.S.Amiri A.Afroozeh m.Bahadoran Department of Physics Science and Research BranchIslamic Azad UniversityTehranIran

A novel system of multisoliton generation using nonlinear equations of the propagating signals is *** system uses a PANDA ring resonator incorporated with an add/drop filter *** resonant conditions,the intense optical fields known as multisolitons can be generated and propagated within a Kerr-type nonlinear *** present simulation results show that multisolitons can be controlled by using additional Gaussian pulses input into the add port of the PANDA *** the soliton pulse in the microring device,a balance should be achieved between dispersion and nonlinear *** output signals from the PANDA ring resonator are input into the add/drop filter *** signals can be filtered by using the add/drop filter system,in which multi dark and bright solitons can be *** this work multi dark and bright solitons with an FWHm and an FSR of 425 pm and 1.145 nm are generated,respectively,where the Gaussian pulse with a central wavelength of 1.55µm and power of 600 mW is input into the system.

关键词： resonator system soliton

Effect of (Ba_(0.6)Sr_(0.4))TiO_3(BST) Doping on Dielectric Properties of CaCu_3Ti_4O_(12)(CCTO)

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Journal of materials Science & Technology 2012年第12期28卷 1137-1144页

作者： i. Norezan A.K. Yahya m.K. Talari Faculty of Applied Sciences Universiti Teknologi MARAShah Alam Selangor Malaysia

The effect of （Ba（0.6）Sr（0.4））TiO3（BST） addition on dielectric properties of CaCu3Ti4O（12）（CCTO） ceramic was investigated. Ceramic samples with the chemical formula （1-x）CaCu3Ti4O（12）＋ x（Ba（0.6）,Sr（0.4））TiO3 （x=0, 0.05, 0.1, and 0.2） were synthesized from high purity oxide powders by the conventional solid-state synthesis method. X-ray diffraction （XRD） analysis showed the existence of BST as a secondary phase alongside CCTO. Scanning electron microscopy （SEm） investigation showed a slight decrease in grain size of doped CCTO samples. Density measurements showed that porosity content increased with increasing BST addition indicating low densification due to high melting point secondary phase addition. Dielectric constant of undoped CCTO （x=0） showed lack of stability with frequency which dropped drastically between 104 and 105Hz and accompanied by high dielectric loss. Addition of BST into CCTO caused the dielectric constant to slightly decrease but improved stability with frequency compared to the undoped sample. The decrease in dielectric constant of doped CCTO samples was suggested to be partly due to the decrease in average grain size and increase in porosity with BST addition. Nevertheless, a high value of dielectric constant was still maintained around ～104 range for all doped samples. The dielectric loss （tanδ） of all BST-doped samples was lower than that of pure CCTO sample at the frequency range of 103 to 105 Hz probably due to the increase of grains boundary resistivity. The activation energy of grains boundary （E（gb）） showed higher values as compared to the activation energy of grains （Eg ） for all samples and conforms to the internal barrier layer capacitor （iBLC） model.

关键词： CaCu3Ti4O(12)(CCTO) Dielectric properties (Ba(0.6)Sr(0.4))TiO3(BST)

On the Generalized Continuity Equation

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Chinese Physics Letters 2010年第8期27卷 117-120页

作者： Arbab i. Arbab Hisham. m. Widatallah Department of Physics Faculty of Science University of Khartoum PO Box 321 Khartoum 11115 Sudan Department of Physics College of Science Sultan Qaboos University PO Box 36 Al-IKhod Muscat 123 Oman

A generalized continuity equation extending the ordinary continuity equation is found using quanternions to show it is compatible with Dirac, Schrǒdinger, Klein-Gordon and diffusion equations. This generalized equation is Lorentz invariant. The transport properties of electrons are found to be governed by the Schr6dinger-like equation and not by the diffusion equation.

关键词： DiFFERENTiAL equations QUATERNiONS DiRAC equation SCHRODiNGER equation KLEiN-Gordon equation ELECTRON transport HEAT equation

A realistic topological p-n junction at the Bi2Se3 （0001） surface based on planar twin boundary defects

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Nano Research 2017年第5期10卷 1784-1793页

作者： Hugo Aramberri m. Carmen munoz Jorge i. Cerda instituto de Ciencia de materiales de madrid (iCmm-CSiC) Cantoblanco Madrid 28049 Spain

We propose a realistic topological p-n junction （TPNJ） by matching two Bi2Se3 （0001） slabs with opposite arrangements of planar twin boundary defects. The atomistic modeling of such a device leads to dislocation defects in the hexagonal lattice in several quintuple layers. Nevertheless, total energy calculations reveal that the interface relaxes, yielding a smooth geometrical transition that preserves the nearest-neighbors fcc-type geometry throughout these defect layers. The electronic, magnetic, and transport properties of the junction have then been calculated at the ab initio level under open boundary conditions, i.e., employing a thin-film geometry that is infinite along the electron transport direction. indeed, a p-n junction is obtained with a built-in potential as large as 350 meV. The calculations further reveal the spin texture across the interface with unprecedented detail. As the main result, we obtain non-negligible transmission probabilities around the F point, which involve an electron spin-flip process while crossing the interface.

关键词： topological insulators p-n junctions spintronics electronic devices twin boundaries

Developing a two-decadal time-record of rice field maps using Landsat-derived multi-index image collections with a random forest classifier:A Google Earth Engine based approach

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information Processing in Agriculture 2024年第2期11卷 260-275页

作者： W.Ashane m.Fernando i.P.Senanayake Department of Nano Science Technology Wayamba University of Sri LankaKuliyapitiya 60200Sri Lanka Dchoolf Engineing CllegeoEngineeringSience and EnionmentThe UniversyewcastleCallaghanW2Austraia

Historic maps showing the temporal distribution of rice fields are important for precision agriculture,irrigation optimisation,forecasting crop yields,land use management and formulating ***,mapping rice felds using traditional ground surveys is impractical when high cost,time and labour requirements are considered,and the availability of such detailed records is *** satellite remote sensing appears to be a viable solution,conventional segmentation and classification methods with spectral bands are often unable to contrast the distinct characteristics between rice fields and other vegetation *** this end,we explored a novel,Google Earth Engine(GEE)based multiindex random forest(RF)classification approach to map rice fields over two *** images from 2000 to 2020 of two Sri Lankan rice cultivation districts were extracted from GEE and a multi-index RF classification algorithm was applied to distinguish the rice *** results showed above 80%accuracy for both training and validation,when compared against high spatial resolution Google Earth *** essence,multi-index sampling and RF together synergised the compelling classifcation accuracy by effectively capturing vegetation,water(ponding)and soil characteristics unique to the rice felds using a single-click *** maps developed in this study were further compared against the mODiS land cover type product(mCD12Q1)and the corresponding superior statistics on rice fields demonstrated the robustness of the proposed *** work seeking effective index combinations is recommended,and this approach can potentially be extended to other crop analyses elsewhere.

关键词： Google Earth Engine(GEE) image classification Random forest mapping rice fields Time series analysis Vegetation index

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

Effect of coaxial laser cladding parameters on bead formation

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international Journal of minerals,metallurgy and materials 2017年第5期24卷 550-556页

作者： A.i.Noskov A.Kh.Gilmutdinov R.m.Yanbaev Kazan National Research Technical University 10 Karl Marx Str. Kazan 420111 Republic of Tatarstan Russian Federation

We investigated the shape and morphology of nickel-based powder particles (Sulzer metco) and coatings produced by laser gas-powder deposition onto steel substrates. Laser deposition was performed using an LC-10 iPG-Photonics laser complex equipped with a 10-kW fiber laser. The shape and microstructure of the samples were studied using optical and electronic microscopy and X-ray diffraction analysis. The results showed that the deposition speed and laser power significantly influenced the shape and size of the beads. The depth of diffusion of nickel into the steel substrate after deposition was less than 20 μm; the microstructure of the resulting coating was fcc Fe3Ni. As a result, detailed information about the form and shape of the filler powder, modes of its deposition, and the resulting coating structure was obtained; this information is important for the production of high-quality products by additive technologies.

关键词： laser cladding additive manufacturing microstructure morphology bead formation