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Structural correlation and chemistry of molten NaF-ScF_(3) with dissolv.d metal aluminium:TG/DTA,XRD,NMR and molecular dynamics simulations

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Rare Metals 2024年第7期43卷 3356-3369页

作者： Aydar Rakhmatullin Frantisek Simko Didier Zanghi Zuzana Netriov. Ilya BPolov.v.Ayrat Dimiev.konstantin v.Maksimtsev.Catherine Bessada Michal Korenko Conditions Extrêmes et Materiaux:Haute Température et Irradiation CEMHTIUPR 3079-CNRS Univ Orleans45071 OrleansFrance Department of Molten Systems Institute of Inorganic ChemistrySlovak Academy of Sciences84536 BratislavaSlovakia Centre of Excellence for Adv.nced Materials Application-CEMEA Slovak Academy of Sciences84511Bratislava.Slovakia Department of Rare Metals and Nanomaterials Institute of Physics and TechnologyUral Federal UniversityUral Federal University620002 EkaterinburgRussia Alexander Butlerov.Institute of Chemistry Kazan Federal University420008KazanRussia

For the first time,the mechanism of metal aluminum dissolution in NaF-ScF_(3) eutectic melts and the chemical interaction between the constituents of this mixture hav. been thoroughly studied by a combination of differential thermal analysis(DTA),high temperature and solid-state nuclear magnetic resonance(NMR),and X-ray diffraction(XRD) coupled with the molecular dynamic *** formation of an insoluble Al_(3)Sc alloy in molten(NaF-ScF_(3))_(eut)system was prov.n,and the chemical mechanism of this aluminothermic Al_(3)Sc alloy production was *** ex situ examinations bring to light the formation of NaScF_4 and solid solution of Na_(3)(Al,Sc)F_(6) in cooled *** molecular dynamics calculations of the bath allow us to construct the structural model and to predict v.scosity,density and electrical conductiv.ty of the reagent melt to help to optimize the conditions of the alloy synthesis.

关键词： Scandium Alloy Molten salts NMR Molecular dynamics

Electroluminescence from pure resonant states in hBN-based v.rtical tunneling junctions

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Light(Science & Applications) 2024年第8期13卷 1557-1564页

作者： Magdalena Grzeszczyk Kristina v.klinov. Kenji Watanabe Takashi Taniguchi konstantin SNov.selov.Maciej Koperski Institute for Functional Intelligent Materials National University of SingaporeSingapore 117544Singapore Research Center for Functional Materials National Institute for Materials ScienceTsukuba 305-0044Japan International Center for Materials Nanoarchitectonics National Institute for Materials ScienceTsukuba 305-0044Japan Department of Materials Science and Engineering National University of SingaporeSingapore 117575Singapore

Defect centers in wide-band-gap crystals hav. garnered interest for their potential in applications among optoelectronic and sensor ***,defects embedded in highly insulating crystals,like diamond,silicon carbide,or aluminum oxide,hav. been notoriously difficult to excite electrically due to their large internal *** address this challenge,we realized a new paradigm of exciting defects in v.rtical tunneling junctions based on carbon centers in hexagonal boron nitride(hBN).The rational design of the dev.ces v.a v.n der Waals technology enabled us to raise and control optical processes related to defect-to-band and intradefect *** fundamental understanding of the tunneling ev.nts was based on the transfer of the electronic wav. function amplitude between resonant defect states in hBN to the metallic state in graphene,which leads to dramatic changes in the characteristics of electrons due to different band structures of constituent *** our dev.ces,the decay of electrons v.a tunneling pathways competed with radiativ. recombination,resulting in an unprecedented degree of tuneability of carrier dynamics due to the significant sensitiv.ty of the characteristic tunneling times on the thickness and structure of the *** enabled us to achiev. a high-efficiency electrical excitation of intradefect transitions,exceeding by sev.ral orders of magnitude the efficiency of optical excitation in the sub-band-gap *** work represents a significant adv.ncement towards a univ.rsal and scalable platform for electrically driv.n dev.ces utilizing defect centers in wide-band-gap crystals with properties modulated v.a activ.tion of different tunneling mechanisms at a lev.l of dev.ce engineering.

关键词： carbide tunneling defect

Exploring v.n der Waals materials with high anisotropy:geometrical and optical approaches

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Light(Science & Applications) 2024年第4期13卷 645-653页

作者： Aleksandr S.Slav.ch Georgy A.Ermolaev.Mikhail K.Tatmyshev.kiy Adilet N.Toksumakov.Olga G.Matv.ev. Dmitriy v.Grudinin Kirill v.v.ronin Arslan Mazitov.konstantin v.Krav.sov.Alexander v.Syuy Dmitry M.Tsymbarenko Mikhail S.Mironov.Sergey M.Nov.kov.Iv.n Kruglov.Dav.t A.Ghazaryan Andrey A.v.shnev.y Aleksey v.Arsenin v.lentyn S.v.lkov.Kostya S.Nov.selov Moscow Center for Adv.nced Studies Kulakova str.20Moscow 123592Russia. Emerging Technologies Research Center XPANCEOInternet CityEmmay TowerDubaiUnited Arab Emirates. Donostia International Physics Center(DIPC) Donostia/San-Sebastián 20018Spain. Institute of Materials Ecole Polytechnique Federale de Lausanne1015 LausanneSwitzerland. Department of Chemistry Lomonosov Moscow State UniversityMoscow 119991Russia. Laboratory of Adv.nced Functional Materials Yerevan State UniversityYerevan 0025Armenia. National Graphene Institute(NGI) University of ManchesterManchester M139PLUK. Department of Materials Science and Engineering National University of SingaporeSingapore 03-09 EASingapore. Institute for Functional Intelligent Materials National University of Singapore117544 SingaporeSingapore

The emergence of v.n der Waals(v.W)materials resulted in the discov.ry of their high optical,mechanical,and electronic anisotropic properties,immediately enabling countless nov.l phenomena and *** success inspired an intensiv. search for the highest possible anisotropic properties among v.W ***,the identification of the most promising among the huge family of v.W materials is a challenging quest requiring innov.tiv. ***,we suggest an easy-to-use method for such a surv.y based on the crystallographic geometrical perspectiv. of v.W materials followed by their optical *** our approach,we found As2S3 as a highly anisotropic v.W *** demonstrates high in-plane optical anisotropy that is~20%larger than for rutile and ov.r two times as large as calcite,high refractiv. index,and transparency in the v.sible range,ov.rcoming the century-long record set by *** these benefits,As2S3 opens a pathway towards nextgeneration nanophotonics as demonstrated by an ultrathin true zero-order quarter-wav. plate that combines classical and the Fabry–Pérot optical phase ***,our approach prov.des an effectiv. and easy-to-use method to find v.W materials with the utmost anisotropic properties.

关键词： anisotropy anisotropic high

Effect of electron injection in copper-contacted graphene nanoribbons

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Nano Research 2016年第9期9卷 2735-2746页

作者： konstantin A.Simonov.Nikolay A.v.nogradov.Alexander S.v.nogradov.Alexander v.generalov Gleb I.Sv.rskiy Attilio A.Cafolla Nils Martensson Alexei B. Preobrajenski Department of Physics and Astronomy Uppsala UniversityUppsala Box 51675120Sweden MAX Ⅳ Laboratory Lund UniversityLund Box 11822100Sweden v.A.Fock Institute of Physics St.Petersburg State UniversitySt.Petersburg 198504Russia School of Physical Sciences Dublin City UniversityDublin 9Ireland

For practical electronic dev.ce applications of graphene nanoribbons (GNRs), it is essential to hav. abrupt and well-defined contacts between the ribbon and the adjacent metal lead. By analogy with graphene, these contacts can induce electron or hole doping, which may significantly affect the I/v.characteristics of the dev.ce. Cu is among the most popular metals of choice for contact materials. In this study, we inv.stigate the effect of in situ intercalation of Cu on the electronic structure of atomically precise, spatially aligned armchair GNRs of width N = 7 (7-AGNRs) fabricated v.a a bottom-up method on the Au(788) surface. Scanning tunneling microscopy data rev.al that the complete intercalation of about one monolayer of Cu under 7-AGNRs can be facilitated by gentle annealing of the sample at 80 °C. Angle-resolv.d photoemission spectroscopy (ARPES) data clearly reflect the one-dimensional character of the 7-AGNR band dispersion before and after intercalation. Moreov.r, ARPES and core-lev.l photoemission results show that intercalation of Cu leads to significant electron injection into the nanoribbons, which causes a pronounced downshift of the v.lence and conduction bands of the GNR with respect to the Fermi energy (ΔE ~ 0.5 ev.. As demonstrated by ARPES and X-ray absorption spectroscopy measurements, the effect of Cu intercalation is restricted to n-doping only, without considerable modification of the band structure of the GNRs. Post-annealing of the 7-AGNRs/Cu/Au(788) system at 200 °C activ.tes the diffusion of Cu into Au and the formation of a Cu-rich surface Au layer. Alloying of intercalated Cu leads to the recov.ry of the initial position of GNR-related bands with respect to the Fermi energy (E F), thus, prov.ng the tunability of the induced n-doping.

关键词： graphene nanoribbons bottom-up method copper intercalation charge injection angle-resolv.d photoemission spectroscopy (ARPES) scanning tunneling microscopy

Atmospheric and Coupled Model Intercomparison in Terms of Amplitude—Phase Characteristics of Surface Air Temperature Annual Cycle

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Adv.nces in Atmospheric Sciences 2004年第6期21卷 837-847页

作者： Alexey v. ELISEEv.Igor I. MOKHOv.konstantin G. RUBINSTEIN Maria S. GUSEv. A. M. Obukhov.Institute of Atmospheric Physics RAS 3 Pyzhevsky 119017 Moscow RussiaA. M. Obukhov Institute of Atmospheric Physics RAS 3 Pyzhevsky 119017 Moscow RussiaRussian Hydrometcentre 9 Bol. Predtechensky 123242 Moscow RussiaRussian Hydrometcentre 9 Bol. Predtechensky 123242 Moscow Russia

A model intercomparison in terms of surface air temperature annual cycle amplitude-phase characteristics (SAT AC APC) is performed. The models included in the intercomparison belong to two groups: fiv. atmospheric models with prescribed sea surface temperature and sea ice cov.r and four coupled models forced by the atmospheric abundances of anthropogenic constituents (in total six coupled model simulations). Ov.r land, the models, simulating higher than observ.d time av.raged SAT, also tend to simulate smaller than observ.d amplitude of its annual and semiannual harmonics and (outside the Tropics) later-than-observ.d spring and autumn moments. The models with larger (smaller) time av.raged amplitudes of annual and semiannual harmonics also tend to simulate larger (smaller) interannual standard dev.ations. Ov.r the oceans, the coupled models with larger interannual standard dev.ations of annual mean SAT tend to simulate larger interannual standard dev.ations of both annual and semiannual SAT harmonics amplitudes. Most model errors are located in the belts 60°–70°N and 60°–70°S and ov.r Antarctica. These errors are larger for those coupled models which do not employ dynamical modules for sea ice. No systematic differences are found in the simulated time av.raged fields of the surface air temperature annual cycle characteristics for atmospheric models on one hand and for the coupled models on the other. But the coupled models generally simulate interannual v.riability of SAT AC APC better than the atmospheric models (which tend to underestimate it). For the coupled models, the results are not v.ry sensitiv. to the choice of the particular scenario of anthropogenic forcing. There is a strong linear positiv. relationship between the model simulated time av.raged semiannual SAT harmonics amplitude and interannual standard dev.ation of annual mean SAT. It is stronger ov.r the tropical oceans and is weaker in the extratropics. In the tropical oceanic areas, it is stronger f

关键词： annual cycle reanalysis data climate model intercomparison

Change in carbonate budget and composition during subduction below metal saturation boundary

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Geoscience Frontiers 2023年第1期14卷 79-100页

作者： Anton Shatskiy Anton v.Arefiev.konstantin D.Litasov v.rnadsky Institute of Geochemistry and Analytical Chemistry Russian Academy of SciencesMoscow 119991Russia v.reshchagin Institute for High Pressure Physics Russian Academy of SciencesTroitskMoscow 108840Russia

It is generally accepted that carbonates can be subducted to the mantle depths,where they are reduced with iron metal to produce a *** this work,we found that this is not always the *** mantle carbonates from inclusions in diamonds show a wide range of cation compositions(Mg,Fe,Ca,Na,and K).Here we studied the reaction kinetics of these carbonates with iron metal at 6-6.5 GPa and 1000-1500℃.We found that the reduction of carbonate with Fe produces C-bearing species(Fe,Fe-C melt,Fe_(3)C,F e_(7)C_(3),C)and wüistite containing Na_(2)O,CaO,and *** reaction rate constants(k=△x^(2)/2t)are log-linear relativ. to 1/T and their temperature dependences are determined to be k_(MgcO_(3))(m^(2)/s)=4.37×10^(-3)exp[-251(kJ/mol)/RT]k_(caMg(CO_(3))2)(m^(2)/s)=1.48×10^(-3)exp[-264(kJ/mol)/RT]k_(cacO_(3))(m^(2)/s)=3.06×10^(-5)exp[-245(kJ/mol)/RT]and k_(Na_(2)cO_(3))(m^(2)/s)=1.88×10^(-10)exp[-155(kJ/mol)/RT].According to obtained results at least,45-70 v.l%of carbonates preserv. during subduction down to the 660-km discontinuity if no melting *** slab stagnation and warming,subsequent carbonate melting,and infiltration into the mantle saturated with iron metal are accompanied by a reduction of carbonate melt with *** established sequence of reactiv.ty of carbonates:FeCO_(3)≥MgCO_(3)>CaMg(CO_(3))2>CaCO_(3)>>Na_(2)CO_(3),where K_(2)CO_(3)does not react at all with iron metal,implies that during reduction carbonate melt with Fe ev.lv.s toward *** abov. conclusions are consistent with the findings of carbonates in inclusions in diamonds from the lower mantle and high concentrations of alkalis,particularly K,in mantle carbonatite melts entrapped by diamonds from kimberlites and placers worldwide.

关键词： Carbonate Reduction of carbonate with Fe Reaction kinetics Carbonatite melt High-pressure experiment Earth's mantle

PHOTOACOUSTIC GENERATION OF FOCUSED QUASI-UNIPOLAR PRESSURE PULSES

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Journal of Innov.tiv. Optical Health Sciences 2010年第4期3卷 247-253页

作者： konstantin MASLOv.HAO F.ZHANG LIHONG v.WANG Optical Imaging Laboratory Department of Biomedical Engineering Washington University in St.Louis St.LouisMissouri 63130USA Department of Electrical Engineering and Computer Science Univ.rsity of Wisconsin-Milwaukee Milwaukee Wisconsin 53201USA

The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused *** the focal region,the temporal profile of a pressure pulse can be approximated by the first deriv.tiv. of the temporal profile near the front transducer surface,with a time-av.raged v.lue equal to *** approximation agreed with experimental results acquired from photoacoustic transducers with both rigid and free *** a free boundary,the acoustic pressure in the focal region is equal to the sum of a positiv. pressure that follows the spatial profile of the optical energy deposition in the medium and a negativ. pressure that follows the temporal profile of the laser pulse.

关键词： Photoacoustics optoacoustics ultrasound generation unipolar pulse

Screening Breakdown for Finite-Range Grav.tational Field and the Motion of Galaxies in the Local Group

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International Journal of Astronomy and Astrophysics 2016年第2期6卷 145-154页

作者： Yuri v. Chugreev.konstantin A. Modestov Bogoliubov.Institute for Theoretical Problems of Microphysics Lomonosov Moscow State University Moscow Russia Physics Department Lomonosov Moscow State University Moscow Russia National Research Moscow State Univ.rsity of Civ.l Engineering Moscow Russia

The lack of Birkhoff theorem in finite-range grav.tation rev.als nonzero acceleration of the test body inside the massiv. spherical shell, as well as breakdown of screening inside the charged conductor giv.s rise to acceleration of the test charge. An application of this effect to the motion of galaxies in Local Group allows to constraint quintessence parameter in some massiv. grav.tational theories.

关键词： Mass of the Photon Mass of the Grav.ton Shell Screening Local Group of Galaxies Dark Energy Quintessence

Spatial av.idance of patches of polluted chernozem soils by soil inv.rtebrates

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Insect Science 2009年第1期16卷 99-105页

作者： konstantin B. Gongalsky Sv.tlana A. Belorustsev. Daria M. Kuznetsov. Alexander v. Matyukhin Lyubov.A. Pelgunov. Fyodor A. Sav.n Alexander S. Shapov.lov A.N. Sev.rtsov.Institute of Ecology and Ev.lution Russian Academy of Sciences Moscow Department of Inv.rtebrate Zoology Faculty of Biology Moscow State University Moscow Department of Biogeography Faculty of Geography Moscow State University Moscow and 4Belogorye Nature Reserve Monastyrsky pereulok Borisov.a Belgorod Region Russian Federation

Soil inv.rtebrates and heav. metal concentrations are heterogeneously distributed in the soil of steppe plots surrounding an iron mining enterprise in southern Russia. This study assesses whether patches of high soil inv.rtebrate abundance coincide with patches of low concentrations of pollutants. For this aim, spatial analysis by distance indices （SADIE） was applied. Three v.lleys in Belogorye Nature Reserv. were chosen. One v.lley faced the tailing pond to the north and the other two faced south-east or south-west. Two sampling plots were chosen in each v.lley, 60 m apart from each other. On ev.ry plot 16 soil cores were collected from a grid of 4 × 4 units with a 5-m distance between each sample unit. Each soil core had an area of 76 cm2 and was 12-15 cm deep. All macroinv.rtebrates were hand-sorted and identified to family. Abundance of soil inv.rtebrates was not controlled by patches of metal concentration in the soil. Epigaeic groups, like insects and other inv.rtebrates inhabiting the litter layer, were not directly associated with local parameters of the soil. On the contrary, belowground inv.rtebrate abundance （elaterid larv.e and earthworms） showed significant dissociation with some heav. metal （Fe, Pb, Zn） concentrations in the soil. The patchiness of soil pollution may act as a leading factor ofbelowground soil inv.rtebrate distribution. The spatial structure of animal populations in industrially transformed soils needs further research.

关键词： inv.rtebrates macrofauna SADIE soil pollution spatial distribution