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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

sb_(2)Te_(3)/graphite nanocomposite: A comprehensive study of thermal conductivity

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Journal of Materiomics 2021年第3期7卷 545-555页

作者： subarna Das P.singha v.A.Kulbachinskii v.G.Kytin Gangadhar Das s.Janaky A.K.Deb sudip Mukherjee A.Maignan s.Hebert R.Daou Chandrabhas narayana s.Bandyopadhyay Aritra Banerjee Department of Physics University of Calcutta92 A P C RoadKolkata700009India Laboratoire de Cristallographie et sciences des Materiaux(CRIsMAT) Normandie UniversiteUMR6508 CNRSENSICAENUNICAEN14000CaenFrance Department of Low Temperature Physics and superconductivity Physics FacultyM.V.Lomonosov Moscow State University119991MoscowRussia Moscow Institute of Physics and Technology 141700DolgoprudnyMoscow RegionRussia Chemistry and Physics of Materials Unit Jawaharlal Nehru Centre for Advanced Scientific ResearchJakkur P.OBangalore560064India Department of Physics Raiganj UniversityUttar DinajpurWest Bengal733134India UGC-DAE Consortium for scientific Research Mumbai CentreR-5 ShedBARC CampusTrombayMumbai400008India Center for Research in Nanoscience and Nanotechnology University of CalcuttaJD-2Sector-IIISaltlakeKolkata700106India

Thermoelectric performance largely depends on the reduction of lattice thermal conductivity(kL).The study of the thermal conductivity(k)of a sb_(2)Te_(3)/graphite nanocomposite system demonstrates-40%reduction in kL with graphite incorporation.A plausible explanation of intrinsic low kL observed in sb_(2)Te_(3) based system is presented by modeling experimental specific heat(Cp)*** spectroscopy measurement combined to X-Ray diffraction data confirms the presence of graphite as separate phase in the composite *** is found that phonon scattering dominates heat transport mechanism in the nanostructured sb_(2)Te_(3)/graphite *** reduction in kL is accomplished by intensifying scattering rate of phonons via various *** introduces effective scattering sources,i.e.,defects of different dimensionalities in synthesized nanocomposite ***,graphite mediates phonon-phonon coupling and enhances lattice anharmonicity,which causes an intrinsic scattering of phonons with all frequencies in the sb_(2)Te_(3)/graphite nanocomposite *** density and phonon anharmonicity of the synthesized samples are estimated from in depth analysis of temperature dependent synchrotron powder diffraction and Raman spectroscopic *** value as low as 0.8 W m1 K1 at 300 K,achieved with graphite dispersion in sb_(2)Te_(3) based composite system makes the present comprehensive study an interesting concept to be developed in thermoelectric materials.

关键词： Thermoelectric systems Thermal conductivity Phonons X-ray powder diffraction Raman spectroscopy specific heat measurements

Application of integrated simulation environment sIEMNED to the analysis of the MEPHIsT-0 tokamak operation

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Plasma science and Technology 2023年第3期25卷 222-233页

作者： D Yu sYCHUGOv s Yu sOLOvIEv A s ZHILKIN A v MELNIKOv s A KRAT Faculty of Computational Mathematics and Cybernetics Lomonosov Moscow State University National Research Centre Kurchatov Institute National Research Nuclear University Moscow Engineering Physics Institute National University Moscow Institute of Physics and Technology

This paper presents the results of numerical simulation of plasma equilibrium and stability in the MEPHIsT-0 tokamak with sIEMNED software and comparison of simulation results with *** determined characteristics of the vacuum chamber show that it significantly affects the entire *** various scenarios of the inductor operation,a comparison of experimental data and simulated currents and magnetic fields induced in the chamber was carried *** steady-state tokamak operation,a numerical study of equilibrium plasma configurations was carried out depending on the currents in the poloidal magnetic field coils and plasma *** vertical plasma instability was *** limiting values of plasma ellipticity preventing the vertical plasma instability were numerically *** simulations show that plasma equilibrium is supported by induced *** was shown numerically that magnetic configuration with‘zero of higher order’were obtained before the plasma shot,suggesting consistency between the simulation results and observations.

关键词： mathematical modelling tokamak installation MEPHIsT-0

Generalised tanh-shaped hyperbolic potential: Klein–Gordon equation's bound state solution

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Communications in Theoretical Physics 2023年第7期75卷 22-32页

作者： v H Badalov s v Badalov Institute for Physical Problems Baku State University1148 BakuAzerbaijan Theoretical Materials Physics Paderborn UniversityD-33098 PaderbornGermany Theoretical PhysicsⅦ University of BayreuthD-95440 BayreuthGermany

The development of potential theory heightens the understanding of fundamental interactions in quantum *** this paper,the bound state solution of the modified radial Klein–Gordon equation is presented for generalised tanh-shaped hyperbolic potential from the Nikiforov–Uvarov *** resulting energy eigenvalues and corresponding radial wave functions are expressed in terms of the Jacobi polynomials for arbitrary l *** is also demonstrated that energy eigenvalues strongly correlate with potential parameters for quantum *** particular cases,the generalised tanh-shaped hyperbolic potential and its derived energy eigenvalues exhibit good agreement with the reported ***,the rovibrational energies are calculated for three representative diatomic molecules,namely H2,HCl and *** lowest excitation energies are in perfect agreement with experimental ***,the potential model is displayed to be a viable candidate for concurrently prescribing numerous quantum systems.

关键词： Klein-Gordon equation hyperbolic potential Nikiforov-Uvarov method diatomic molecules

Effect of Dy-substitution on structural and magnetic properties of Mn-Zn ferrite nanoparticles

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Journal of Rare Earths 2018年第1期36卷 86-94页

作者： K.v.Zipare s.s.Bandgar G.s.shahane Department of Electronics DBF Dayanand College of Arts and Science

This paper describes the structural and magnetic properties of Dy-substituted Mn-Zn ferrite nano- particles. Mn-Zn-Dy ferrite nanopafficles of the composition ***204 （x- 0.05, 0.1, 0.15 and 0.2） were synthesized by a facile chemical co-precipitation method. The samples were characterized through X-ray diffraction （XRD）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR）, vibrating sample magnetometer （vsM） and Curie temperature. The XRD patterns confirm the synthesis of single crystalline phase of Mn-Zn-Dy ferrite nanoparticles. Lattice parameter increases with increase in Dy-substitution which confirms the replacement of Fe3＋ ions by Dy3＋ ions. Crystallite size is of the order of 6-8 nm for all these samples. The particle sizes observed from TEM analysis are in good agreement with the XRD values. The magnetic measurements show super- paramagnetic nature of the samples. The saturation magnetization decreases with increase in Dy- concentration and can be correlated to modifications in the A-B exchange interactions as a result of the structural modifications due to Dy-substitution. The Curie temperature for ***204 nano- particles is 124 ℃ and decreases up to 84 ℃with the increase in the Dy-concentration. The decrease in Curie temperature can be attributed to the weakening of the superexchange interaction between A-site and B-site as a result of Dy-substitution. The low value of Curie temperature and higher value of ther- momagnetic coefficient kT shown by these samples makes them suitable for the preparation of tem- perature sensitive ferrofiuid for heat transfer applications.

关键词： Mn-Zn-Dy ferritesstructural characterizationMagnetic propertiesCurie temperatureRare earths

Nanoimprint lithography steppers for volume fabrication of leading-edge semiconductor integrated circuits

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Microsystems & Nanoengineering 2017年第1期3卷 116-134页

作者： s.v.s.eenivasan Department of Mechanical Engineering NASCENT CenterThe University of Texas at AustinJ.J.Pickle Research CampusBuilding 16010100 Burnet RoadAustinTX 78712USA Canon Nanotechnologies Inc. AustinTX 78758USA

This article discusses the transition of a form of nanoimprint lithography technology,known as Jet and Flash Imprint Lithography(J-FIL),from research to a commercial fabrication infrastructure for leading-edge semiconductor integrated circuits(ICs).Leadingedge semiconductor lithography has some of the most aggressive technology requirements,and has been a key driver in the 50-year history of semiconductor *** a new,disruptive capability into this arena is therefore a case study in a“highrisk-high-reward”*** article first discusses relevant literature in nanopatterning including advanced lithography options that have been explored by the IC fabrication industry,novel research ideas being explored,and literature in nanoimprint *** article then focuses on the J-FIL process,and the interdisciplinary nature of risk,involving nanoscale precision systems,mechanics,materials,material delivery systems,contamination control,and process ***,the article discusses the strategic decisions that were made in the early phases of the project including:(i)choosing a step and repeat process approach;(ii)identifying the first target IC market for J-FIL;(iii)defining the product scope and the appropriate collaborations to share the risk-reward landscape;and(iv)properly leveraging existing infrastructure,including minimizing disruption to the widely accepted practices in ***,the paper discusses the commercial J-FIL stepper system and associated infrastructure,and the resulting advances in the key lithographic process metrics such as critical dimension control,overlay,throughput,process defects,and electrical yield over the past 5 *** article concludes with the current state of the art in J-FIL technology for IC fabrication,including description of the high volume manufacturing stepper tools created for advanced memory manufacturing.

关键词： jet and flash imprint nanoscale overlay nanoimprint defectivity semiconductor fabrication steppers precision systems Uv nanoimprint

Modelling Magnetoresistance Effect in Limited Anisotropic semiconductors

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Chinese Physics Letters 2017年第7期34卷 212-214页

作者： Filippov v.v. Mitsuk s.v. Lipetsk state Pedagogical University of P. P. semenov-Tyan-shansky Lipetsk 398020 the Russian Federation Lipetsk state Technical University Lipetsk 398600 the Russian Federation

A macroscopic model of the magnetoresistance effect in fimited anisotropic semiconductors is built. This model allows us to solve the problem of measurement of physical magnetoresistance components of crystals and films. Based on a unified mathematical model the method is worked out enabling us to measure tensor components of the specific electrical resistance and the relative magnetoresistance of anisotropic semiconductors simultaneously.

关键词： Modelling Magnetoresistance Effect in Limited Anisotropic semiconductors

Design of self-healing PEO-based protective layers containing in-situ grown LDH loaded with inhibitor on the MA8 magnesium alloy

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Journal of Magnesium and Alloys 2023年第10期11卷 3688-3709页

作者： A.s.Gnedenkov s.L.sinebryukhov A.D.Nomerovskii v.s.Filonina A.Yu.Ustinov s.v.Gnedenkov Institute of Chemistry of FEB RAs 159 Pr.100-letiya VladivostokaVladivostok690022Russia

The high corrosion rate of magnesium and its alloys in chloride-containing solution significantly reduces the potential of this material for diverse ***,the formation of a smart protective coating was achieved in this work to prevent degradation of the MA8 magnesium alloy.A porous ceramic-like matrix was obtained on the material by plasma electrolytic oxidation(PEO).Further surface functionalization was performed using layered double hydroxides(LDH) served as nanocontainers for the corrosion *** methods of LDH intercalation with benzotriazole(BTA) were *** composition and morphology of the formed coating were studied using sEM-EDX analysis,XRD,XPs,and Raman *** corrosion behavior of the coated samples was evaluated using electrochemical impedance spectroscopy and potentiodynamic *** corrosion rate was estimated using volumetry and gravimetry *** formed composite coating provides the Mg alloy with the lowest corrosion activity(|Z|_(f)=0.1 Hz)=8.48·10^(5) Ω·cm^(2),I_(c)=1.4·10^(-8)A/cm^(2),P_(H)=0.21 mm/year) and improves the protective properties of the PEO-coated sample(|Z|_(f)=0.1 Hz)=8.37·10^(3) Ω·cm^(2),I_(c)=4.1·10^(-7)A/cm^(2),P_(H)=0.31 mm/year).The realization of the self-healing effect of the inhibitor-containing LDH/PEO-coated system was studied using localized electrochemical methods(svET and sIET) with two artificial defects on the surface.A mechanism involving three stages for the active corrosion protection of the alloy was *** findings contribute to the follow-up work of developing modified LDH/PEO-based structures that promote the Mg alloy with high corrosion resistance,superior electrochemical performance for applications in various fields of industry and medicine.

关键词： Magnesium alloy Plasma electrolytic oxidation Layered double hydroxides Corrosion inhibitor Electrochemistry Corrosion rate

Esterification of levulinic acid to n-butyl levulinate over heteropolyacid supported on acid-treated clay

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Journal of Natural Gas Chemistry 2011年第1期20卷 18-24页

作者： s. Dharne v. v. Bokade Catalysis Division National Chemical Laboratory (CSIR)

Levulinic acid has been identified as a promising green, biomass-derived platform chemical. n-Butyl levulinate is used as an important intermediate having diverse applications. The present work focuses on the synthesis of n-butyl levulinate by esterification of levulinic acid with n-butanol using heteropolyacid （HPA） supported on acid-treated clay montmorillonite （K10）. 20% （w/w） dodecatungestophosphoric acid （DTPA） supported on K10 was found to be the most efficient catalyst with 97% levulinic acid conversion and 100% selectivity towards n-butyl levulinate. Effects of various process parameters were studied to examine the efficacy of 20% （w/w） DTPA/K10 for optimization of the activity.

关键词： levulinic acid n-butanol dodectungestophosphoric acid K10 n-butyl levulinate