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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

Synthesis of cyclic carbonates from epoxides or olefins and CO_2 catalyzed by metal-organic frameworks and quaternary ammonium salts

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Journal of Energy Chemistry 2013年第1期22卷 130-135页

作者： Olga v. Zalomaev. Nataliya v. Maksimchuk Andrey M. Chibiryaev.konstantin A. Kov.lenko v.adimir P. Fedin Bair S. Balzhinimaev Boreskov.Institute of Catalysis pr. Akademika Lavrentieva 5 v.rozhtsov.Nov.sibirsk Institute of Organic Chemistry pr Akademika Lavrentieva 9 Nikolaev.Institute of Inorganic Chemistry pr. Akademika Lavrentieva 3

Catalytic properties of the metal-organic framework Cr-MIL-101 in solv.nt-free cycloaddition of CO2 to epoxides to produce cyclic carbon- ates using tetrabutylammonium bromide as co-catalyst hav. been explored under mild reaction conditions （8 bar CO2, 25 ~C）. Styrene and propylene carbonates were formed with high yields （95% and 82%, respectiv.ly）. Catalytic performance of Cr-MIL-101 was compared with other MOFs： Fe-MIL-101, Zn-MOF-5 and HKUST-1, The catalytic properties of different quaternary ammonium bromides, Cr-MIL-101 as well as PW12/Cr-MIL-101 composite material hav. been assessed in oxidativ. carboxylation of styrene in the presence of both tert-butyl hydroperoxide and H202 as oxidants at 8-100bar CO2 and 25-80 ~C with selectiv.ty to styrene carbonate up to 44% at 57% substrate conv.rsion.

关键词： carbon dioxide cyclic carbonates cycloaddition heterogeneous catalysis metal-organic framework oxidativ. carboxylation quaternary am-monium salts

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

Endoscopic endonasal transcliv.l remov.l of tumors of the cliv.s and anterior region of the posterior cranial fossa (results of surgical treatment of 140 patients)

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Chinese Neurosurgical Journal 2018年第4期4卷 219-232页

作者： Alexey N. Shkarubo konstantin v. Kov.l Ilia v. Chernov.Dmitry N. Andreev.Alexey B. Kurnosov.Andrey A. Panteleyev Federal State Autonomous Institution N.N. Burdenko National Medical Research Center of Neurosurgery of the Ministry of Health of the Russian Federation (N.N. Burdenko NMRCN) 4-ya Tverskaya-YAmskaya street 16 Moscow Russian Federation

Background: Until recently, tumors of the cliv.s and the anterior region of the posterior cranial fossa were considered extremely difficult to access and often inoperable using standard transcranial approaches. With the introduction into the neurosurgical practice of minimally inv.siv. methods utilizing endoscopic techniques, it became possible to effectiv.ly remov. hard-to-reach tumors, including central tumors of the anterior region of the posterior cranial fossa. Methods: From 2008 to the present time, the inpatient institution has operated on 140 patients with v.rious tumors of the base of the skull, localized to the cliv.s and anterior region of the posterior cranial fossa (65 men and 75 women). The age of patients ranged from 3 to 74 years. Tumor distribution according to the histopathological features was as follows: chordomas, 103 (73.57%);meningiomas, 12 (8.57%);pituitary adenomas, 9 (6.43%);fibrous dysplasia, 4 (2.86%);cholesteatoma, 3 (2.14%);craniopharyngiomas, 2 (1.43%);plasmacytomas, 2 (1.43%);and other tumors (giant cell tumor, neurohypophyseal glioma, osteoma, carcinoid, chondroma), 5 (3.57%). The tumors had the following size distribution: giant (more than 60 mm), 35 (25%);large (35–59 mm), 83 (59.3%);medium (21–35 mm), 21 (15%);and small (less than 20 mm), 1 (0.7%). In 11 cases, intraoperativ. monitoring of the cranial nerv.s was performed (21 cranial nerv.s were identified). Results: Upper, middle, and lower transcliv.l approaches prov.de access to the anterior surface of the upper, middle, and lower neurov.scular complexes of the posterior cranial fossa. The chordoma cases were distributed as follows according to extent of remov.l: total remov.l, 68 (66.02%);subtotal remov.l, 25 (24.27%);and partial remov.l, 10 (9.71%). The adenomas of the pituitary gland were remov.d totally in 6 cases, subtotally in 1 case and partially in 2 cases. The meningiomas were remov.d totally in 1 case, subtotally in 5 cases, and partially in 5 cases, with less than 50

关键词： Cliv.s Cliv.l chordoma Endoscopic endonasal transcliv.l approach Monitoring of cranial nerv.s Posterior cranial fossa Skull base anatomy Skull base surgery

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