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Journal of Environmental sciences 2011年第12期23卷 1989-1998页

作者： T. s. Anirudhan s. s. sreekumari Department of Chemistry University of Kerala Kariavattom Trivandrum-695 581 India

Activated carbon （AC） derived from waste coconut buttons （CB） was investigated as a suitable adsorbent for the removal of heavy metal ions such as Pb（II）, Hg（II） and Cu（II） from industrial effluents through batch adsorption process. The AC was characterized by elemental analysis, fourier transform infrared spectroscopy, X-ray diflraction, scanning electron microscopy, thermal gravimetric and diflerential thermal analysis, surface area analyzer and potentiometric titrations. The eflects of initial metal concentration, contact time, pH and adsorbent dose on the adsorption of metal ions were studied. The adsorbent revealed a good adsorption potential for Pb（II） and Cu（II） at pH 6.0 and for Hg（II） at pH 7.0. The experimental kinetic data were a better fit with pseudo second-order equation rather than pseudo first-order equation. The Freundlich isotherm model was found to be more suitable to represent the experimental equilibrium isotherm results for the three metals than the Langmuir model. The adsorption capacities of the AC decreased in the order： Pb（II） Hg（II） Cu（II）.

关键词： coconut buttons heavy metal ions adsorption isotherm wastewater desorption

CaMoO_4:Dy^(3+),K^+ near White Light Emitting Phosphor:structural,Optical and Dielectric Properties

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Journal of Materials science & Technology 2013年第7期29卷 633-638页

作者： s.K.sharma s.Dutta s.som P.s.Mandal Department of Applied Physics Indian School of MinesDhanbad 826004India

Undoped, Dy^3＋ doped and Dy^3＋, K^＋ codoped calcium molybdate phosphors have been synthesized by solid-state reaction method. X-ray diffraction studies reveal the tetragonal structure of the prepared phosphors having crystallite size 15-50 nm. scanning electron microscopy （sEM） studies reveal the morphology and crystallite size of the prepared phosphors. Photoluminescence studies indicate that there are blue and yellow emissions at 489 and 576 nm, respectively corresponding to Dy^3＋ ion. The introduction of K＋ ion significantly influences the blue and yellow emissions which causes the near white light emission from this codoped phosphor. The intense absorption peak of the codoped phosphor at 210 nm is attributed to the band gap and a shoulder at 240 nm appears due to charge transfer from oxygen ions to neighbouring molybdenum ions. The band gap of the codoped phosphor is calculated as 5.5 eV from the absorption studies. The dielectric properties such as permittivity and dielectric loss are studied as a function of *** The authors are thankful to the Department of science and Technology, New Delhi （Government of India） for funding this work under the Project sR/FTP/Ps-087/2010.

关键词： X-ray diffraction Photoluminescence Absorption Dielectric

Theoretical analysis of slip flow on a rotating cone with viscous dissipation effects

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Journal of Hydrodynamics 2015年第4期27卷 616-623页

作者： sALEEM s. NADEEM s. Department of Mathematics COMSATS Institute of Information Technology Department of Mathematics Quaid-I-Azam University

This paper is concerned with the mutual effects of viscous dissipation and slip effects on a rotating vertical cone in a viscous fluid. similarity solutions for rotating cone with wall temperature boundary conditions provides a system of nonlinear ordinary differential equations which have been treated by optimal homotopy analysis method（OHAM）. The obtained analytical results in comparison with the numerical ones show a noteworthy accuracy for a special case. Effects for the velocities and temperature are revealed graphically and the tabulated values of the surface shear stresses and the heat transfer rate are entered in tables. From the study it is seen that the slip parameter γ enhances the primary velocity while the secondary velocity reduces. Further it is observed that the heat transfer rate Nu Re-1/2x increases with Eckert number Ec and Prandtl number Pr.

关键词： mixed convection incompressible flow differential equations slip effects viscous dissipation

Multiwavelets domain singular value features for image texture classification

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Journal of Zhejiang University-science A(Applied Physics & Engineering) 2007年第4期8卷 538-549页

作者： RAMAKRIsHNAN s. sELVAN s. Department of Information Technology PsG College of Technology Coimbatore 641 004India

A new approach based on multiwavelets transformation and singular value decomposition (sVD) is proposed for the classification of image textures. Lower singular values are truncated based on its energy distribution to classify the textures in the presence of additive white Gaussian noise (AWGN). The proposed approach extracts features such as energy, entropy, local homogeneity and max-min ratio from the selected singular values of multiwavelets transformation coefficients of image textures. The classification was carried out using probabilistic neural network (PNN). Performance of the proposed approach was compared with conventional wavelet domain gray level co-occurrence matrix (GLCM) based features, discrete multiwavelets transformation energy based approach, and HMM based approach. Experimental results showed the superiority of the proposed algorithms when compared with existing algorithms.

关键词： Image texture classification Multiwavelets transformation Probabilistic neural network (PNN)

PREPARATION OF POLYETHERsULFONE ULTRAFILTRATION MEMBRANEs FOR MILK CONCENTRATION AND EFFECTs OF ADDITIVEs ON THEIR MORPHOLOGY AND PERFORMANCE

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Chinese Journal of Polymer science 2005年第5期23卷 539-548页

作者： s.s.Madaeni A.Rahimpour Department Of Chemical Engineering Razi University KermanshahIran

Polyethersulfone membranes were prepared from quaternary systems containing N,N-dimethylacetamide （DMAc） as solvent, polyvinylpyrrolidone （PVP） as constant additive and acetic acid, acetone and water as variable additives. Phase inversion via immersion precipitation was employed for manufacturing of membranes. The prepared films were immersed in the mixture of pure water and 2-propanol （30/70 vol%） as the non-solvent. Acetic acid caused an increment in the flux at high polymer concentration （16 wt%） and a decline in the flux at low polymer concentrations （10 wt% and 13 wt%）. Acetone and water as the solvent in the casting solution declined the flux at any polymer concentration tested. The morphology and performance of the prepared membranes were investigated by scanning electron microscopy and separation experiments using milk as the feed.

关键词： Membrane Ultrafiltartion Polyethersulfone Phase inversion Milk.

Field-dependent resistive transitions in YBa_2Cu_3O_(7-δ) thin films:Influence of the pseudogap on vortex dynamics

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Chinese Physics B 2015年第1期24卷 467-473页

作者： s H Naqib R s Islam Department of Physics University of RajshahiRajshahi-6205 Bangladesh

The nature of resistive transition of high-quality crystalline thin films of YBa2Cu3O7-δhas been studied under magnetic fields（H） applied along the c direction over a wide range of doped holes, p, in the Cu O2 planes. The field- and temperature-dependent in-plane resistivity, ρab（T, H）, has been analyzed within the thermally assisted flux-flow（TAFF）formalism. The flux activation energy, U（T, H）, has been extracted from this analysis. The low-T part of the ρab（T, H）data can be described by an activation energy having the functional form of U（T, H） =（1- t）m（H-0/H）β, where t = T /Tc（reduced temperature）, and H0 is a field scale that primarily determines the magnitude of U（T, H）. The temperature exponent, m, shows a systematic variation with p, whereas the field exponent, β, is insensitive to the p values and is close to unity. The H0, on the other hand, changes rapidly as p is varied. U（T, H） is linked to the pinning potential and consequently on the superconducting condensation energy. since the normal state pseudogap directly affects superconducting condensation energy, a clear correspondence between H0 and the PG energy scale, ε g, is found. Possible implications of these results are discussed.

关键词： Y123 superconductors thermally assisted flux-flow model activation energy pseudogap

Operational Tau Approximation for the Fokker-Planck Equation

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Chinese Physics Letters 2012年第4期29卷 141-144页

作者： s.s.Dehcheshmeh s.Karimi Vanani J.s.Hafshejani Department of Mathematics Islamic Azad UniversityFarsan BranchFarsanIran

An extension of the operational Tau method (OTM) is used to solve the Fokker Planck equation arising in many physical *** extension yields an algebraic equivalent representation of the desired problem using arbitrary polynomial basis functions to decrease the size of the *** structure,properties and advantages of the OTM are presented,and some illustrative linear and nonlinear experiments are given to show the capability and efficiency of the proposed algorithm.

关键词： problems Approximation polynomial

Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

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Frontiers of structural and Civil Engineering 2019年第3期13卷 542-556页

作者： s.sAMANTA s.s.s.NANTHAKUMAR R.K.ANNABATTULA X.ZHUANG Institute of Continuum Mechanics Leibniz University Hannover30167 HannoverGermany Indian Institute of Technology Madras Chennai 600036India College of Civil Engineering Tongji UniversityShanghai 200092China

The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve,leading to quick-prediction of the parameters of single circular *** this work,mode-shape dependent shifting phenomenon of peaks of impedance curve with change in void location has been analyzed.A number of initial guesses followed by an iterative optimization algorithm based on univariate method has been used to solve the *** each iteration starting from each initial guess,the difference between the computationally obtained impedance curve and the target impedance curve has been *** methodology has been extended to detect single circular metallic inclusion in 2D piezoelectric cantilever beam.A good accuracy level was observed for detection of flaw radius and flaw-location along beam-length,but not the precise location along beam-width.

关键词： piezoelectricity impedance curve mode shapes inverse problem flaw detection curve shifting

Hydroxyapatite-containing PEO-coating design for biodegradable Mg-0.8Ca alloy: Formation and corrosion behaviour

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Journal of Magnesium and Alloys 2023年第12期11卷 4468-4484页

作者： A.s.Gnedenkov s.L.sinebryukhov V.s.Filonina s.V.Gnedenkov Institute of Chemistry of FEB RAs 159 Pr.100-letiya VladivostokaVladivostok690022Russian Federation

In this study, the biocompatible protective coating was formed using plasma electrolytic oxidation(PEO) on bioresorbable Mg-0.8Ca alloy. The composition of the formed coating was studied using XRD, sEM-EDX analysis, and micro-Raman spectroscopy. The uniform distribution of hydroxyapatite over the thickness of protective PEO-layer was established. Using traditional(EIs, PDP, OCP) and local scanning electrochemical methods(sVET, sIET with H^(+)-selective microelectrode), the level of protective properties of PEO-layer in a biological environment(mammalian cell culture medium, MEM) was determined. It was established that modification of Mg-0.8Ca alloy surface by PEO contributes to a significant increase in the corrosion resistance of the surface layer, making it possible to control the process of material‘s biodegradation. The maximum local electrochemical activity was recorded after 72 h of testing, while for the uncoated sample,intense corrosion degradation was recorded in the first 12 min of exposure to the cell culture medium. Formation of the PEO-coating results in a twofold decrease in the corrosion current density(2.8·10^(-6)A cm^(-2)) and an increase in the impedance modulus measured at a low frequency(1.7·10^(4)Ω cm^(2)) in comparison with the uncoated material(9.5·10^(-6)A cm^(-2);8.1·10^(3)Ω cm^(2)). The mechanism of material bioresorption was established and a model for biodegradation process of Mg-0.8Ca alloy with hydroxyapatite-containing PEO-coating in MEM was proposed. Analysis of these results and comparing with others obtained by various scientific groups indicate the prospects for application of biocompatible PEO-coating on Mg-Ca alloy in implant surgery.

关键词： Magnesium-calcium alloy Biodegradation Implant surgery Plasma electrolytic oxidation Electrochemistry Minimum essential medium Hydroxyapatite

Oriented colloidal-crystal thin films of polystyrene spheres via spin coating

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Journal of semiconductors 2015年第2期36卷 10-17页

作者： s.s.shinde s.Park Korea Research Institute of standards and science

We developed a simple and inexpensive synthesis of a large-scale close-packed monolayer of polystyrene sphere arrays, which have a variety of applications. The influence of three step spin speeds, spinning time, solution quantity and relative humidity is studied in order to achieve a large area close-packed monolayer. A relatively high surface coverage and uniform monolayer of Ps spheres in the range of 85%-90% are achieved by appropriate control of the preparative parameters. Also the effect of the oxygen plasma etching process on the reduction of Ps spheres has been studied. We conclude that it can be useful in industrial applications, because of the fabrication speed, surface coverage, control over Ps spheres and cost of the process.

关键词： monolayer Ps spheres oxygen plasma