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Influence of Zr and Mn additions on microstructure and properties of Mg-2.5wt%Cu-Xwt%Zn(X=2.5,5 and 6.5)alloys

International Journal of Minerals,Metallurgy and Materials 2022年第9期29卷 1733-1745页

作者： A.v.Koltygin v.e.Bazhenov I.v.Plisetskaya v.A.Bautin A.I.Bazlov N.Y.Tabachkova O.O.voropaeva A.A.Komissarov v.D.Belov Foundry Department National University of Science and Technology(MISiS)Moscow 119049Russia Department of Metallurgy Steel New Production Technologies and Protection of MetalsNational University of Science and Technology(MISiS)Moscow 119049Russia Laboratory of Advanced Green Materials National University of Science and Technology(MISiS)Moscow 119049Russia Department of Materials Science of Semiconductors and Dielectrics National University of Science and Technology(MISiS)Moscow 119049Russia Fianit Laboratory(Laser Materials and Technology Research Center at GPI) Prokhorov General Physics Institute RASMoscow 119991Russia Laboratory of Hybrid Nanostructured Materials National University of Science and Technology(MISiS)Moscow 119049Russia Laboratory of Medical Bioresorption and Bioresistance Moscow State University of Medicine and DentistryMoscow 127473Russia

This work studied the effects of adding Zr and Mn in amounts less than 1wt%on the microstructure,mechanical properties,casting properties,and corrosion resistance of Mg-Zn-Cu alloys containing 2.5wt%Cu and 2.5wt%-6.5wt%*** hardness and electrical conductivity measurements were used to find an optimal heat treatment schedule with the best mechanical *** has been established that Zr significantly increases the yield strength of the alloys due to a strong grain refinement ***,the presence of Mn and Zr has a detrimental effect on alloy’s elongation at *** was shown that the precipitation of the Mg_(2)Cu cathodic phase in the alloy structure negatively affects the corrosion ***,the addition of Mn decreases the corrosion rate of the investigated *** best combination of the mechanical,casting,and corrosion properties were achieved in the alloys containing 2.5wt%Cu and 5wt%***,the Mn or Zr addition can improve the properties of the alloys;for example,the addition of Mn or Zr increases the fluidity of the alloys.

关键词： magnesium alloy Mg-Zn-Cu casting alloy Mn addition Zr addition

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Accretivity of the General Second Order Linear Differential Operator

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Acta Mathematica Sinica,english Series 2019年第6期35卷 832-852页

作者： v.G.MAZ'YA I.e.veRBITSKY Department of Mathematics Linkoping University SE-581 83 Linkoping Sweden RUDN University 6 Miklukho-Maklay St. Moscow 117198 Russia Department of Mathematics University of Missouri Columbia Missouri 65211 USA

For the general second order linear differential operator ■ with complex-valued distributional coefficients a_(jk), b_j, and c in an open set Ω ? R^n(n ≥ 1), we present conditions which ensure that-L^0 is accretive... 详细信息

关键词： Accretive differential operators complex-valued coefficients Schr?dinger operator form boundedness

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LIve IMAGING OF eARLY DeveLOPMeNTAL PROCeSSeS IN MAMMALIAN eMBRYOS WITH OPTICAL COHeReNCe TOMOGRAPHY

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Journal of Innovative Optical Health Sciences 2009年第3期2卷 253-259页

作者： KIRILL v.LARIN IRINA v.LARINA MICHAeL LIeBLING MARY e.DICKINSON Department of Biomedical engineering University of Houston HoustonTXUSA Department of Molecular Physiology and Biophysics Baylor College of Medicine HoustonTXUSA Department of electrical and Computer engineering University of California Santa BarbaraCAUSA

early embryonic imaging of cardiovascular development in mammalian models requires a methodthat can penetrate through and distinguish the many tissue layers with high spatial and temporalresolution. In this paper we evaluate the capability of Optical Coherence Tomography (OCT)technique for structural 3D embryonic imaging in mouse embryos at different stages of thedevelopmental process ranging from 7.5 dpc up to 10.5 dpc. Obtained results suggest that thecollected data is suitable for quantitative and qualitative measurements to assess cardiovascularfunction in mouse models, which is likely to expand our knowledge of the complexity of theembryonic heart, and its development into an adult heart.

关键词： Optical Coherence Tomography non-invasive mouse embryos cardiovascular function.

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Arsenic contamination of groundwater:A global synopsis with focus on the Indian Peninsula

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Geoscience Frontiers 2021年第3期12卷 1-18页

作者： e.Shaji M.Santosh K.v.Sarath Pranav Prakash v.Deepchand B.v.Divya Department of Geology University of KeralaKariavattom CampusTrivandrum 695581India School of earth Sciences and Resources China University of Geosciences(Beijing)29 Xueyuan RoadBeijing 100083China Department of earth Science University of AdelaideAdelaideSA 5005Australia

More than 2.5 billion people on the globe rely on groundwater for drinking and providing high-quality drinking water has become one of the major challenges of human *** groundwater is considered as safe,high concentrations of heavy metals like arsenic(As)can pose potential human health concerns and *** this paper,we present an overview of the current scenario of arsenic contamination of groundwater in various countries across the globe with an emphasis on the Indian *** several newly affected regions reported during the last decade,a significant increase has been observed in the global scenario of arsenic *** is estimated that nearly 108 countries are affected by arsenic contamination in groundwater with concentration beyond maximum permissible limit of 10 ppb recommended by the World Health *** highest among these are from Asia(32)and europe(31),followed by regions like Africa(20),North America(11),South America(9)and Australia(4).More than 230 million people worldwide,which include 180 million from Asia,are at risk of arsenic *** Asian countries,Bangladesh,India,Pakistan,China,Nepal,vietnam,Burma,Thailand and Cambodia,are the most *** India,20 states and 4 Union Territories have so far been affected by arsenic contamination in *** attempt to evaluate the correlation between arsenic poisoning and aquifer type shows that the groundwater extracted from unconsolidated sedimentary aquifers,particularly those which are located within the younger orogenic belts of the world,are the worst *** than 90%of arsenic pollution is inferred to be *** infer that alluvial sediments are the major source for arsenic contamination in groundwater and we postulate a strong relation with plate tectonic processes,mountain building,erosion and *** consumption of arsenic-contaminated groundwater results in severe health issues like skin,lung,kidney and bladder ca

关键词： Arsenic contamination Groundwater Indo-Gangetic alluvium Orogenic belts Global tectonics Asia

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ADSORPTION AND ReLeASING PROPeRTIeS OF BeAD CeLLULOSe

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Chinese Journal of Polymer Science 2004年第5期22卷 417-423页

作者： A.Morales e.Bordallo v.Leon J.Rieumont FacultyofChemistryandPharmacy CentralUniversityofLasVillas.Camajuanikm51／2VillaClaraSantaClara54830Cuba Research-ProductionPlantCuba9 QuivicanHavanaCuba FacultyofChemistry HavanaUniversityAveZapataandGHavana10400Cuba

The adsorption of some dyes on samples of bead cellulose obtained in the Unit of Research-Production 'Cuba 9' was studied. Methylene blue, alizarin red and congo red fitted the adsorption isotherm of Langmuir. Adsorption kinetics at pH = 6 was linear with the square root of time indicating the diffusion is the controlling step. At pH = 12 a non-Fickian trend was observed and adsorption was higher for the first two dyes. experiments carried out to release the methylene blue occluded in the cellulose beads gave a kinetic behavior of zero order. The study of cytochrome C adsorption was included to test a proteinic material. Crosslinking of bead cellulose was performed with epichlorohydrin decreasing its adsorption capacity in acidic or alkaline solution.

关键词： Bead cellulose Adsorption Isotherms Kinetics of adsorption Dyes

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Late Mesozoic topographic evolution of western Transbaikalia:evidence for rapid geodynamic changes from the Mongol-Okhotsk collision to widespread rifting

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Geoscience Frontiers 2020年第5期11卷 1695-1709页

作者： A.v.Arzhannikova e.I.Demonterova M.Jolivet S.G.Arzhannikov e.A.Mikheeva A.v.Ivanov v.B.Khubanov L.A.Pavlova Institute of the earth’s Crust Russian Academy of SciencesSiberian BranchIrkutskRussia Laboratoire Geosciences Rennes CNRS-UMR6118Universite de RennesRennesFrance Geological Institute Russian Academy of SciencesSiberian BranchUlan-UdeRussia A.P.vinogradov Institute of Geochemistry Siberian Branch of the Russian Academy of SciencesIrkutskRussia

The Mesozoic geodynamic evolution of Transbaikalia has been largely controlled by the scissors-like closure of the Mongol-Okhotsk Ocean that separated Siberia from Mongolia-North China *** the oceanic closure,the tectonic evolution of that region was characterized by collisional uplift and subsequent extension that gave rise to the formation of metamorphic core *** complex tectonic setting prevailed simultaneously between 150 Ma and 110 Ma both in Transbaikalia,North Mongolia,and within the North China *** paleobotanical and paleontological data show that the oldest Mesozoic basins had formed in western Transbaikalia before the estimated age of extension *** no precise geochronological age is available for the onset of extension in *** Tugnuy Basin,as probably the oldest Mesozoic basin in western Transbaikalia,is a key obj ect to date the onset of extension and following changes in tectonic *** this study,U-Pb(LA-ICP-MS)dating of detrital zircons from three key Jurassic sediment formations of the Tugnuy Basin are used to identify the potential source areas of the sediments,understand the changes in sediment routing and provide insights on the topographic evolution of western *** results show several significant changes in tectonic regime after the closure of the Mongol-Okhotsk Ocean.A wide uplifted plateau formed during the closure of the Mongol-Okhotsk Ocean,determining the early Jurassic drainage system reaching the Angaravitim batholith to the north and shedding sediments to the continental margin to the *** following collisional event at the end of the early Jurassic led to the uplift of the collision zone,which partially inverted the drainage system toward the North.A strike-slip displacement induced by the oblique collision initiated some of the early Transbaikalian depressions,such as the Tugnuy Basin at about 168 Ma.A phase of basin inversion,marked by folding and ero

关键词： U–Pb detrital zircons dating Topographic evolution Mongol–Okhotsk collision Transbaikalia

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Concrete damage diagnosed using the non-classical nonlinear acoustic method

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Chinese Physics B 2009年第5期18卷 1898-1905页

作者：周到刘晓宙龚秀芬 Nazarov v e 马力 Key Laboratory of Modern Acoustics Ministry of EducationInstitute of AcousticsNanjing University Institute of Applied Physics Russian Academy of ScienceRussian Federation Institute of Acoustics Chinese Academy of Sciences

It is known that the strength of concrete is seriously affected by damage and cracking. In this paper, six concrete samples under different damage levels are studied. The experimental results show a linear dependence of the resonance frequency shift on strain amplitude at the fundamental frequency, and approximate quadratic dependence of the am- plitudes of the second and third harmonics on strain amplitude at the fundamental frequency as well. In addition, the amplitude of the third harmonics is shown to increase with the increase of damage level, which is even higher than that of the second harmonics in samples with higher damage levels. These are three properties of non-classical nonlinear acoustics. The nonlinear parameters increase from 106 to 108 with damage level, and are more sensitive to the damage level of the concrete than the linear parameters obtained by using traditional acoustics methods. So, this method based on non-classical nonlinear acoustics may provide a better means of non-destructive testing （NDT） of concrete and other porous materials.

关键词： concrete non-classical nonlinear acoustics non-destructive testing (NDT) crack

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effect of Nitrogen Doping on the electrical Properties of 3C-SiC Thin Films for High-Temperature Sensors Applications

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Acta Metallurgica Sinica(english Letters) 2014年第1期27卷 168-174页

作者： H.K.e.Latha A.Udayakumar v.Siddeswara Prasad Department of Instrumentation Technology Siddaganga Institute of Technology Materials Science Division Council of Scientific and Industrial Research-National Aerospace Laboratories

3C-SiC is a promising structural material for piezoresistive sensors used in high-temperature applications. For sensor development, the preparation of sensor materials and study of its electrical properties, such as resistivity, barrier height of grain boundaries, and temperature coefficient of resistivity, are important in addition to structural properties and these have to be optimized. In the present work, 3C-SiC thin film with in situ doping of nitrogen is prepared through low- pressure chemical vapor deposition by using methyl trichloro silane, ammonia, and hydrogen as precursors. electrical properties of deposited 3C-SiC thin films with varying nitrogen doping concentration through four probe technique are studied. Atomic force microscopy investigations are carried out to study the grain size on and average root-mean-squared roughness 3C-SiC thin films. A decrease in the degree of crystallinity is observed in nitrogen-doped 3C-SiC thin films. The sheet resistivity of nitrogen-doped 3C-SiC thin film is found to decrease with increase in temperature in the range from 303 to 823 K. The sheet resistivity, average temperature coefficient of resistance, and barrier height of the grain boundaries of film doped with 17 at.% of nitrogen are 0.14 cm, -1.0 x 10-n/K, and 0.01 ev, respectively. Comparing all the nitrogen-doped 3C-SiC thin films, the film doped with 17 at.% of nitrogen exhibits an improved structural and electrical properties and it can be used as sensing material for high-temperature applications.

关键词： Low-pressure chemical vapor deposition (LPCvD) 3C-SiC thin film Resistivity Barrier height of grain boundaries: Temperature coefficient of resistivitv (TCR)

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emission of high-energy alpha particles in nuclear reactions of ^(48)Ca and ^(56)Fe ions on ^(181)Ta and ^(238)U targets

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Chinese Physics C 2022年第11期46卷 177-194页

作者： Yu.e.Penionzhkevich v.v.Samarin S.M.Lukyanov v.A.Maslov M.A.Naumenko Flerov Laboratory of Nuclear Reactions Joint Institute for Nuclear ResearchDubna 141980Russia Department of experimental Methods in Nuclear Physics National Research Nuclear UniversityMoscow 115409Russia Department of Nuclear Physics Dubna State UniversityDubna 141982Russia

The results of experiments on measuring the energy spectra of alpha particles in reactions with heavy ions are *** measurements were performed using the high-resolution magnetic analyzer MAvR with beams of ^(48)Ca(280 Mev)and ^(56)Fe(320 and 400 Mev)on ^(181)Ta and ^(238)U targets at an angle of 0°.A strong dependence of the double differential cross sections for production of alpha particles on the atomic number of the target nucleus was observed,which indicates that fast alpha particles are mainly emitted from the target nucleus;this conclusion was also confirmed by calculations within the time-dependent Schrödinger equation *** analysis of the obtained experimental data was carried out within the model of moving sources modified to consider the kinematic limits for two-body and three-body exit channels.

关键词： alpha particle energy spectra two-and three-body kinematic limits model of moving sources time-dependent Schrodinger equation

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Analysis of a constant height hydraulic fracture driven by a power-law fluid

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Rock Mechanics Bulletin 2022年第1期1卷 108-118页

作者： e.v.Dontsov ResFrac Corporation 555 Bryant St.#185Palo Alto94301CAUSA

The focus of this study is to analyze a parametric space for the problem of a constant height hydraulic fracture driven by a power-law *** interplay of physical mechanisms related to toughness,fluid resistance,and leakoff is considered,but the model is restricted to local elasticity for *** problem of a semi-infinite constant height fracture is first analyzed:limiting solutions are obtained analytically and their locations inside the dimensionless parametric space are ***,the problem of a finite constant height fracture is ***,limiting vertex solutions are first outlined and then their locations in the parametric space are *** demonstrate that the effect of the power-law factor is relatively mild,as it does not significantly distort the parametric *** the same time,there are quantitative differences,which are also determined by the obtained *** examples highlighting the effect of fracture regime on morphology of multiple fractures are presented at the end.

关键词： Constant height hydraulic fracture Analysis Analytic solutions Fracture propagation regimes

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