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Structural evolution-enabled BiFeO3 modulated by strontium doping with enhanced dielectric,optical and superparamagnetic properties by a modified sol-gel method

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Chinese Physics B 2023年第3期32卷 521-530页

作者： Sharon v S veena Gopalan e Malini K A Department of Physics vimala College Thrissur-9 KeralaIndia

Multiferroic(BFO)nanoparticles doped with strontium with the general formula Bi1-xSrx FeO3(x=0,0.3,0.5,0.7)were synthesized using a modified sol-gel auto-combustion *** structural,electrical,optical,and magnetic properties of the samples are *** structural analysis,carried out using the x-ray powder diffraction technique,shows a structural transition from rhombohedral(R-3c)to cubic(Pm-3m)for the doping amount of strontium(Sr)equal to x=*** analysis of the prepared samples were carried out using scanning electron microscopy(SeM).Frequency-dependent dielectric constant and ac conductivity were *** doped samples,with improved dielectric properties,can be used to fabricate different optoelectronic *** dielectric dispersion and broad relaxation were exhibited by all the ***–Cole plots were employed as an effective tool to study the dispersion parameters,namely,the optical dielectric constant,static dielectric constant,relaxation time,and spreading *** activation energy was calculated from the relaxation peaks and Cole–Cole plots,which were found to be compatible with each *** bandgap of the samples was calculated using diffuse reflectance spectral(DRS)*** and strong photoluminescence in the IR region was observed in the samples,similar to ZnO,which was reported for the first ***-temperature and low-temperature magnetization studies point towards the superparamagnetic nature of the samples,with an improvement in magnetic properties with *** antiferromagnetic behavior of bulk bismuth ferrite transforms to superparamagnetic in nature for both pure and Sr-substituted bismuth ferrite nanoparticles due to the close dimensions of crystallite size with magnetic domains leading to the break-down of the frustrated spin cycloidal moment.

关键词： multiferroics sol-gel process x-ray spectra optical and dielectric properties

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Chirping instabilities produced by a runaway electron beam at a spherical tokamak

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Plasma Science and Technology 2023年第7期25卷 19-24页

作者： I M BALACHeNKOv N N BAKHARev v K GUSev M v ILIASOvA e M KHILKevICH P S KOReNev A e KONKOv v B MINAev Yu v MITRIZHKIN M I PATROv Yu v PeTROv N v SAKHAROv A e SHeveLev O M SKReKeL Ioffe Institute Saint-Petersburg 194021Russia Lomonosov Moscow State University Moscow 119991Russia

Two different types of MHD instabilities with rapidly chirping frequency were found to arise in the Globus-M2 spherical tokamak in substantially different frequency *** first type arises at frequencies of an order of 1 MHz in ohmic plasmas at relatively low density(n_(e))e range of toroidal magnetic fields and plasma *** type of instability was identified as compressional Alfven waves,driven by electrons,accelerated during a sawtooth *** was found that the mode frequency is sweeping in time,according to the Berk-Breizman hole-clump nonlinear chirping *** second type of wave arises in a specific single-swing regime of the central solenoid current with a very narrow plasma column,when the plasma tends to decay at extremely low density(n_(e))e runaway electron *** exited modes cover the whole observed frequency range and are divided into several(two or three)frequency regions:approximately 0-30 MHz,60-120 MHz and sometimes 30-60 *** of the branches was also *** chirps are more rapid than for 1 MHz Alfven instability and follow an exponential *** paper,to our knowledge,is the first report of frequency chirping instabilities excited by accelerated electrons at a spherical tokamak.

关键词： Alfvén waves chirping instability spherical tokamak runaway electrons

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A Spectral Atlas of F and G Stars

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Chinese Journal of Astronomy and Astrophysics 2004年第3期4卷 279-283页

作者： v.G.Klochkova GangZhao v.e.Panchuk S.v.ermakov NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012 SpecialAstrophysicalObservatoryRussianAcademyofSciences NizhnijArkhyzKarachai-Cherkessia369167Russia

We present an atlas of a group of bright stars in the range of spectral classes F–G and luminosity classes I–v. The spectra were obtained with spectral resolution R ~ 15 000 within spectral region 4500–6620?. Typical spectra of stars with different metallicity [Fe/H] are included. We also show the digital version of the spectral data in FITS format.

关键词： stars: atlas stars: spectral class stars: F-G type

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AMS studies on a 450 km long 2216 Ma dyke from Dharwar craton, India:Implications to magma flow

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Geoscience Frontiers 2019年第5期10卷 1931-1939页

作者： e. Nagaraju v. Parashuramulu Paleomagnetism Division CSIR-National Geophysical Research InstituteUppal RoadHyderabad-500007India TSMS Jr. College BaswapurPulkalSangareddy DistrictTelanganaIndia

Anisotropy of magnetic susceptibility (AMS) studies were carried out on a precisely dated (2216.0 ± 0.9 Ma),450 km long NeS striking dyke in the Dharwar Craton,to determine.the.magma flow direction along the dyke *** order to use.the.imbrication of the magnetic foliation,forty eight samples were collected from 13 locations along the length of the *** studies show that AMS fabric is dominated by medium grained interstitial Ti-poor multidomain *** corrected anisotropy degree (Pj) of the samples was found to be low to moderate,between 1.007 and 1.072,which indicates primary magnetic *** magnetic ellipsoid is e.the. triaxial,prolate or oblate and clearly defines normal,intermediate and inverse magnetic fabrics related to magma flow during the dyke *** maximum susceptibility axes (Kmax) of the AMS tensor of the dyke is predominantly inclined at low angles (ematic variation in depth along the NeS profile,indicating sub-horizontal flow even at mid crustal levels which could probably be governed by location of the focal region of the magma source (mantle plume?),flow dynamics together with the compressive stresses exerted by the overlying crust.

关键词： Anisotropy of magnetic susceptibility Dharwar craton Dyke swarms

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The lacustrine sedimentary records of coal-burning atmospheric pollution

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Science China earth Sciences 2005年第10期48卷 1740-1746页

作者： e. Appel v. Hoffmann Institut für Geowissenschaften Universitt Tübingen 72076 Tübingen GermanyInstitut für Geowissenschaften Universitt Tübingen 72076 Tübingen Germany

Based on the studies on diatom, ostracods and magnetism on a core acquired from lacustrine sediments, as well as correlation analysis between concentration of acid diatom and the instantaneous lowest pH value, the processes of environment evolution in Lake Yangzonghai were reconstructed. The lacustrine environment was favorable in the 1950s, and began to be polluted by a coal-burning power plant since 1960. During 1965―1980, the instantaneous lowest pH value of lake water decreased to 5―6 when heavily polluted. There was a decrease trend in the pollution from 1983 to 1999, but coal-burning atmospheric pollution was still a main problem for environmental retrieving. As acid precipitated, acid-tolerant species overspread, and shellfish disappeared, as well as ferromagnetic particulates dissolved because of the consequent change of pH-eh values in the interface of water and soil, which results in the change of environmental proxies versus depth. Thus, the environmental evolution of Lake Yangzonghai is reconstructed in this paper based on the inferences mentioned above.

关键词： atmospheric pollution, proxies, environmental reconstruction, lacustrine sediment, Lake Yangzonghai.

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SCIeNTIFIC PRINCIPLeS FOR MODIFICATION OF WATeR-SOLUBLe POLYMeRS. FORMATION OF MACROMOLeCULAR COMPLeXeS

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Chinese Journal of Polymer Science 1998年第3期16卷 268-278页

作者： PAUTOv v.D. ANUFRIevA e.v. KRAKOvYAK M.G. Institute of Macromolecular Compounds RAS Bolshoy pr. 31 St. Petersburg 199004 RussiaInstitute of Macromolecular Compounds RAS Bolshoy pr. 31 St. Petersburg 199004 RussiaInstitute of Macromolecular Compounds RAS Bolshoy pr. 31 St. Petersburg 199004 Russia

The study of nanosecond dynamics of macromolecules with the lumines-cent methods make it possible to investigate.the.formation and functioning of polymericcomplexes, polymeric conjugates and macromolecular metal complexes, which are widelyused for solving many practical tasks. The nanosecond dynamics of macromolecules are ahighly sensitive indicator of interpolymer complexes (IPC) formation. It enables us to solvethe problems of studying IPC formation and stability and to investigate.the.interpolymerreactions of exchange and substitution. The investigation of changes in the rotational mo-bility of globular protein molecules as a whole makes it possible to determine.the.complexcomposition and its stability, and to control the course of polymer-protein conjugate forma-tion reaction. The nanosecond dynamics of polymers interacting with surfacants' ions (S)are.the.sensitive indicator of the S-polymer complex formation. A method for determin-ing the equilibrium constants of the S-polymer complex formation was developed on thebasis of the study of polymer chains mobility. It is established that nanosecond dynamicsinfluences the course of chemical reactions in polymer chains. Moreover, the marked effectof the nanosecond dynamics is also revealed in the study of photophysical processes (theformation of excimers and energy migration of electron excitation) in polymers with pho-toactive groups. It was found that the efficiency of both processes increases with increasingthe mobility of side chains, the carriers of photoactive groups.

关键词： Modification of water-soluble polymers Formation of complexes

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Processes underlying the laser photochromic effect in colloidal plasmonic nanoparticle aggregates

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Chinese Physics B 2020年第3期29卷 412-419页

作者： A e ershov v S Gerasimov I L Isaev A P Gavrilyuk S v Karpov Institute of Computational Modeling SB RAS 660036KrasnoyarskRussia Siberian Federal University Krasnoyarsk660041Russia Kirensky Institute of Physics Federal Research Center KSC SB RAS660036KrasnoyarskRussia Siberian State University of Science and Technology Krasnoyarsk 660014Russia

We have studied the dynamic and static processes occurring in disordered multiparticle colloidal Ag aggregates with natural structure and affecting their plasmonic absorption spectra under pico-and nanosecond pulsed laser radiations, as well as the physical origin responsible for these processes. We have shown that depending on the duration of the laser pulse.the.mechanisms of laser modification of such aggregates can be associated both with changes in the resonant properties of the particles due to their heating and melting(picosecond irradiation mode) and with the particle shifts in the resonant domains of the aggregates(nanosecond pulses) which depend on the wavelength, intensity, and polarization of the *** mechanisms result in formation of a narrow dip in the plasmonic absorption spectrum of the aggregates near the laser radiation wavelength and affect the shape and position of the dip. The effect of polydispersity of nanoparticle aggregates on laser photochromic reaction has been studied.

关键词： nanoparticle surface plasmon resonance photochromic process pulsed laser radiation

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Growth performance,oxidative stress and immune status of newly weaned pigs fed peroxidized lipids with or without supplemental vitamin e or polyphenols

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Journal of Animal Science and Biotechnology 2020年第3期11卷 819-829页

作者： Y.v.Silva-Guillen C.Arellano R.D.Boyd G.Martinez e.van Heugten Department of Animal Science North Carolina State UniversityRaleighNC 27695USA Department of Statistics North Carolina State UniversityRaleighNC 27695USA The Hanor Company Inc FranklinKY 42134USA

Background:This study evaluated the use of dietary vitamin e and polyphenols on growth,immune and oxidative status of weaned pigs fed peroxidized lipids.A total of 192 piglets(21 days of age and body weight of 6.62±1.04 kg)were assigned within sex and weight blocks to a 2×3 factorial arrangement using 48 pens with 4 pigs per *** treatments consisted of lipid peroxidation(6%edible soybean oil or 6%peroxidized soybean oil),and antioxidant supplementation(control diet containing 33 IU/kg DL-α-tocopheryl-acetate;control with 200 IU/kg additional dl-α-tocopheryl-acetate;or control with 400 mg/kg polyphenols).Pigs were fed in 2 phases for 14 and 21 days,***:Peroxidation of oil for 12 days at 80°C with exposure to 50 L/min of air substantially increased peroxide values,anisidine value,hexanal,and 2,4-decadienal *** peroxidized lipids decreased(Peight(23.16 vs.18.74 kg),daily gain(473 vs.346 g/d),daily feed intake(658 vs.535 g/d)and gain:feed ratio(719 vs.647 g/kg).Lipid peroxidation decreased serum vitamin e(Pecrease was larger on day 35(1.82 vs.0.81 mg/kg)than day 14(1.95 vs.1.38 mg/kg).Supplemental vitamin e,but not polyphenols,increased(P≤0.002)serum vitamin e by 84%and 22%for control and peroxidized diets,respectively(interaction,P=0.001).Serum malondialdehyde decreased(Peroxidation on day 14,but not day 35 and protein carbonyl increased(Peroxidation on day 35,but not day *** 8-hydroxydeoxyguanosine was not affected(P>0.05).Total antioxidant capacity decreased with peroxidation(Peased with vitamin e(P=0.065)and polyphenols(P=0.046)for the control oil diet *** cytokine concentrations increased with feeding peroxidized lipids on day 35,but were not affected by antioxidant supplementation(P>0.05).Conclusion:Feeding peroxidized lipids negatively impacted growth performance and antioxidant capacity of nursery *** of vitamin e and po

关键词： Antioxidants Immune status Lipid peroxidation Oxidative stress Piglets Polyphenols vitamin e

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effects of mechanical activation on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation tailings

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International Journal of Mining Science and Technology 2016年第6期26卷 1043-1049页

作者： ermolovich e.A. ermolovich O.v. Faculty of Mining and Natural Resource Management Belgorod State National Research University Geo Stroy Monitoring Bel GU LTD

The effects of mechanical activation in a planetary mill on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation railings generated by wet magnetic separation process were studied using X-ray and laser diffraction methods. The results revealed the relationship between variations in the mean particle size of activated powders and the milling time. The crystallite size, microstrain, lattice parameters and unit cell volumes were determined for different milling times in powder samples of quartz, hematite, dolomite, and magnetite from the beneficiation tailings. The main trends in the variation of the crystallite size of quartz, hematite, dolomite, and magnetite as a function mean particle size of powder samples were revealed. Changes in the particle shape as a function of the activation time was also investigated.

关键词： Ferruginous quartzite beneficiation tailings Mechanical activation Crystallites Planetary mill Microstructure Structural changes

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Review on high repetition rate and mass production of the cryogenic targets for laser IFe

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High Power Laser Science and engineering 2017年第2期5卷 28-51页

作者： I.v.Aleksandrova e.R.Koresheva Lebedev Physical Institute Russian Academy of SciencesMoscow119991Russia National Research Nuclear University MePhl(Moscow engineering Physics Institute) Moscow115409Russia

In inertial fusion energy(IFe) research, a considerable attention has recently been focused on the issue of large target fabrication for MJ-class laser facilities. The ignition and high-gain target designs require a condensed uniform layer of hydrogen fuel on the inside of a spherical shell. In this report, we discuss the current status and further trends in the area of developing the layering techniques intended to produce ignition, and layering techniques proposed to high repetition rate and mass production of IFe targets.

关键词： free-standing and line-moving targets high-repetition-rate fuel supply inertial fusion energy target mass production

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