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Microstructural evaluation and nanohardness of an AlCoCuCrFeNiTi high-entropy alloy

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 634-641页

作者： C.D.Gómez-Esparza r.Peréz-Bustamante J.M.Alvarado-Orozco J.Mu?oz-Salda?a r.Martínez-Sánchez J.M.Olivares-ramírez A.Duarte-Moller Centro de Investigación en Materiales Avanzados (CIMAV) Laboratorio Nacional de Nanotecnología CONACYT-Corporación Mexicana de Investigación en Materiales S.A.de C.V.(COMIMSA) Centro de Ingeniería y Desarrollo Industrial Querétaro Campus Centro de Investigación y de Estudios Avanzados del IPN Unidad Querétaro Universidad Tecnológica de San Juan del río Escuela de Ingeniería Civil Industrialy Mecánica Universidad De La Salle Bajío

An AlCoCuCrFeNiTi high-entropy alloy(HEA) was prepared by mechanical alloying and sintering to study the effect of Ti addition to the widely studied AlCoCuCrFeNi system. The structural and microstructural characteristics were investigated by X-ray diffraction(XrD), scanning electron microscopy(SEM), and transmission electron microscopy(TEM). The formation of four micrometric phases was detected: a Cu-rich phase with a face-centered cubic(fcc) structure, a body-centered cubic(bcc) solid solution with Cu-rich plate-like precipitates(fcc), an ordered bcc phase, and a tetragonal structure. The XrD patterns corroborate the presence of a mixture of bcc-, fcc-, and tetragonal-structured phases. The Vickers hardness of the alloy under study was more than twice that of the AlCoCuCrFeNi alloy. Nanoindentation tests were performed to evaluate the mechanical response of the individual phases to elucidate the relationship between chemical composition, crystal structure, and mechanical performance of the multiphase microstructure of the AlCoCuCrFeNiTi HEA.

关键词： high-entropy alloys mechanical alloying microstructure nanoindentation

Linearized Oscillations in Nonlinear Delay Difference Equations

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Acta Mathematica Sinica,English Series 1999年第4期15卷 569-574页

作者： Sanyi Tang Department of Computer and Mathematics,Hubei Institute for Nationalities,Enshi 445000,P.r.ChinaYanni Xiao Institute of Mathematics,Academia Sinica,Beijing 100080,P.r.China E-mail:xyn@math03.math.ac.cnJufang Chen Department of Mathematics,Shanxi Normal University,Xi’an 710062,P.r.China Department of Computer and Mathematics Hubei Institute for Nationalities Enshi P. R. China Institute of Mathematics Academia Sinica Beijing P. R. China Department of Mathematics Shanxi Normal University Xi’an P. R. China

Consider the nonlinear delay difference equation xn+1-xn+sum j=1 to m pjfj（xn-kj）=0. We establish a linearized oscillation result of this equation,which is the extension of the result in the paper [1].

关键词： Delay difference equation Oscillatory Nonoscillatory

Insight of surface treatments for CMOS compatibility of InAs nanowi

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Nano research 2019年第3期12卷 581-586页

作者： Daya S. Dhungana Anne Hemeryck Nicolo Sartori Pier-Francesco Fazzini Filadelfo Cristiano Sebastien r. Plissard CNrS LAAS-CNRS Universite de Toulouse F-31400 Toulouse France LPCNO INSA Universite de Toulouse Toulouse France

A CMOS compatible process is prese nted in order to grow self-catalyzed InAs nano wires on silic on by molecular beam epitaxy. The crucial step of this process is a new in-situ surface preparation under hydrogen (gas or plasma) during the substrate degassing combined with an in-situ arsenic ann eali ng prior to growth. Morphological and structural characterizati ons of the InAs nano wires are prese nted and growth mecha nisms are discussed in detail. The major in flue nee of surface termi nation is exposed both experime ntally and theoretically using statistics on ensemble of nanowires and density functional theory (DFT) calculations. The differences observed between Molecular Beam Epitaxy (MBE) and Metal Organic Vapor Phase Epitaxy (MOVPE) growth of I nAs nano wires can be explai ned by these differe nt surfaces termi nations. The transition between a vapor solid (VS) and a vapor liquid solid (VLS) growth mechanism is presented. Optimized growth conditions lead to very high aspect ratio nano wires (up to 50 nm in diameter and 3 micron in len gth) without passi ng the 410℃ thermal limit, which makes the whole process CMOS compatible. Overall, our results suggest a new method for surface preparation and a possible tuning of the growth mechanism using different surface termi nations.

关键词： Ⅲ-Ⅴ semiconductors on silicon InAs nanowires self-catalyzed growth hydrogen preparation growth modeling density functional theory (DFT) modeling

Molecular and cellular consequences of human mutations in NADPH-Cytochrome P450 reductase with various redox partners

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Molecular and cellular consequences of human mutations in NA...

removing ammonium from water and wastewater using cost-effective adsorbents:A review

药物基因组学和药物代谢酶及基因调控国际研讨会

作者： Christopher C.Marohnic Satya P.Panda Wayne L.Backes Warren J.huber.III Michel Kranendonk Jung-Ja P.Kim Bettie Sue Masters University of Texas Health Science Center at San Antonio 7703 Floyd Curl DriveSan AntonioTX 78229-3900 USA Louisiana State University Health Sciences Center 533 Bolivar St.New OrleansLA 70112-1393 USA Universidade Nova de Lisboa Rua da Junqueira96 1349-008LisbonPortugal Medical College of Wisconsin 8701 Watertown Plank Rd.MilwaukeeWI 53226-4801

＜正＞The remarkable finding by Miller and his colleagues that human deficiencies in NADPH-cytochrome P450 reductase （CYPOr） are associated with skeletal malformations and sexual dimorphisms（Fluck et al.,Nat Genet,2004）,has set into motion a number of studies to determine the origin of these defects in the development of the human *** findings prompted our laboratory to examine the physico-chemical properties of these human mutant proteins to

关键词： human NADPH-cytochrome P450 reductase(CYPOr) mutants biplasmid expression of microsomal enzymes heme oxygenase-1 CYP1A2 and CYP4A4 crystal structures of mutant forms of human CYPOr

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Journal of Environmental Sciences 2018年第1期30卷 174-197页

作者： Jianyin Huang Nadeeka rathnayake Kankanamge Christopher Chow David T.Welsh Tianling Li Peter r.Teasdale Natural and Built Environments research Centre School of Natural and Built EnvironmentsUniversity of South AustraliaSA 5095Australia Future Industries Institute University of South AustraliaSA 5095Australia Enuironmental Futures research Institute School of EnuironmentGriffith UniuersityGold Coast campusQLD 4215Australia

Ammonium is an important nutrient in primary production; however, high ammonium loads can cause eutrophication of natural waterways, contributing to undesirable changes in water quality and ecosystem structure. While ammonium pollution comes from diffuse agricultural sources, making control difficult, industrial or municipal point sources such as wastewater treatment plants also contribute significantly to overall ammonium *** latter sources can be targeted more readily to control ammonium release into water systems. To assist policy makers and researchers in understanding the diversity of treatment options and the best option for their circumstance, this paper produces a comprehensive review of existing treatment options for ammonium removal with a particular focus on those technologies which offer the highest rates of removal and cost-effectiveness. Ion exchange and adsorption material methods are simple to apply, cost-effective, environmentally friendly technologies which are quite efficient at removing ammonium from treated water. The review presents a list of adsorbents from the literature, their adsorption capacities and other parameters needed for ammonium removal. Further, the preparation of adsorbents with high ammonium removal capacities and new adsorbents is discussed in the context of their relative cost, removal efficiencies, and limitations. Efficient, cost-effective, and environmental friendly adsorbents for the removal of ammonium on a large scale for commercial or water treatment plants are provided. In addition, future perspectives on removing ammonium using adsorbents are presented.

关键词： Ammonium Water treatment Capacities Cost-effective Environmental friendly

Low Pressure DC Glow Discharge Air Plasma Surface Treatment of Polyethylene (PE) Film for Improvement of Adhesive Properties

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Plasma Science and Technology 2013年第1期15卷 56-63页

作者： Krishnasamy NAVANEETHA PANDIYArAJ Vengatasamy SELVArAJAN rajendrasing r. DESHMUKH Coimbatore. Paramasivam YOGANAND Suresh BALASUBrAMANIAN Sundaram MArUTHAMUTHU Department of Physics Sri Shakthi Institute of Engineering and Technology Plasma Physics Laboratory Department of Physics Bharathiar University Department of Physics Institute of Chemical Technology Microbial-Corrosion Laboratory Central Electrochemical Research Institute

The present work deals with the change in surface properties of polyethylene （PE） film using DC low pressure glow discharge air plasma and makes it useful for technical applications. The change in hydrophilicity of the modified PE film surface was investigated by measuring contact angle and surface energy as a function of exposure time. Changes in the morphological and chemical composition of PE films were analyzed by atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS）. The improvement in adhesion was studied by measuring T-peel and lap-shear strength. The results show that the wettability and surface energy of the PE film has been improved due to the introduction of oxygen-containing polar groups and an increase in surface roughness. The XPS result clearly shows the increase in concentration of oxygen content and the formation of polar groups on the polymer surface. The AFM observation on PE film shows that the roughness of the surface increased due to plasma treatment. The above morphological and chemical changes enhanced the adhesive properties of the PE＇film surfaces, which was confirmed by T-peel and lap-shear tests.

关键词： glow discharge plasma PE hydrophilicity XPS and adhesion

Electron localization of H_2^+ in a dc electric field

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Chinese Physics B 2017年第1期26卷 170-175页

作者： Z M Jia Z N Zeng W T Tang r X Li State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China Signal and Information Processing Jingchu University of Technology Jingmen 448000 China

A dc electric field is utilized to steer the electron motion after the molecular ion H2-＋ is excited by an ultrashort ultraviolet laser pulse. The numerical simulation shows that the electron localization distribution and the dissociation control ratio are dependent on the polarization direction and amplitude of the dc electric field. Most electrons of the dissociation state move opposite to the dc electric field and stabilize at the dressed-up potential well, for the dressed-down well is occupied by the electrons of the 1 sσg state.

关键词： dissociation localization time dependent Schrdinger equation Coulomb potential ultraviolet laser pulse

Hydrodynamics of gas-solid fluidization of a homogeneous ternary mixture in a conical bed:Prediction of bed expansion and bed fluctuation ratios

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Particuology 2013年第6期11卷 681-688页

作者： D.T.K.Dora S.r.Panda Y.K.Mohanty G.K.roy Department of Chemical Engineering Gandhi Institute of Engineering and Technology(GIET) Department of Chemical Engineering National Institute of Technology(NIT)

Hydrodynamic characteristics of fluidization in a conical or tapered bed differ from those in a columnar bed because the superficial velocity in the bed varies in the axial direction. Fixed and fluidized regions could coexist and sharp variations in pressure drop could occur, thereby giving rise to a noticeable pressure drop-flow rate hysteresis loop under incipient fluidization conditions. To explore these unique properties, several experiments were carried out using homogeneous, well-mixed, ternary mixtures with three dif- ferent particle sizes at varying composition in gas-solid conical fluidized beds with varying cone angles. The hydrodynamic characteristics determined include the minimum fluidization velocity, bed fluctuation, and bed expansion ratios. The dependence of these quantities on average particle diameter, mass fraction of the fines in the mixture, initial static bed height, and cone angle is discussed. Based on dimensional analysis and factorial design, correlations are developed using the system parameters, i.e. geometry of the bed （cone angle）, particle diameter, initial static bed height, density of the solid, and superficial velocity of the fluidizing medium. Experimental values of minimum fluidization velocity, bed fluctuation, and bed expansion ratios were found to agree well with the developed correlations.

关键词： Gas-solid fluidization Conical bed Homogeneous ternary mixtures Bed fluctuation ratio Bed expansion ratio

regeneration patterns of key pine species in a mixed-pine forest indicate a positive effect of variable retention harvesting and an increase in recruitment with time

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Forest Ecosystems 2020年第4期7卷 659-671页

作者： Priscilla A.Nyamai P.Charles Goebel r.Gregory Corace III David M.Hix Natural resources Management Program Grand Valley State University1 Campus DrAllendaleMI 49401USA. Department of Forest Rangelandand Fire SciencesUniversity of Idaho875 Perimeter Drive MS 1133MoscowID 83844USA. Alpena-Montmorency Conservation District 1900 M-32 WAlpenaMI 49707USA. School of Environment and Natural resources The Ohio State University2021 Coffey RoadColumbusOH 43210USA.

Background:Many fire-dependent forests have experienced significant declines in species,structural,and functional *** changes are attributed in part to traditional management approaches that were dominated by even-aged regeneration methods such as *** retention harvesting(VrH)is an ecologically based forestry practice that involves retention of some mature overstory trees and other biological structures in the postharvest stand to emulate the effects of natural disturbance *** this study,we examined the effect of a VrH treatment on recruitment of historically dominant pine species and understory vegetation twoand six years after its implementation in a naturally regenerated mixed pine forest in the Upper Peninsula of Michigan,***:We found greater regeneration of red pine(Pinus resinosa L.)and eastern white pine(Pinus strobus L.)in VrH stands compared to the unharvested *** red pine recruitment was very low during the first 2 years,both species increased significantly from year two to year *** responses for the two species did not differ significantly between the aggregated and dispersed retention *** also found high recruitment of deciduous tree species,consisting primarily of sprouts,and red pine exhibited a negative correlation with these ***,time,and the interaction of treatment and time were significant factors in red pine *** had a strong effect on the understory vegetation,with significant decreases in shrubs and ferns over ***:The results suggest that VrH enhanced recruitment of red pine and eastern white pine and that this recruitment increased with *** identify competition from sprouts and unfavorable seedbed conditions as the main factors that limited recruitment of red pine during the first 2 *** reduce competing vegetation and improve seedbed conditions,we suggest following the VrH with a prescribed fire,mechanically removing s

关键词： Variable retention harvesting Aggregated retention Dispersed retention Mixed-pine forest Pinus resinosa Pinus strobus