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Joint effect of quasicrystalline icosahedral and L1_(2)-strucutred phases precipitation on the grain structure and mechanical properties of aluminum-based alloys

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Journal of Materials Science & Technology 2021年第28期87卷 196-206页

作者： A.G.Mochugovskiy N.yu.Tabachkova M.Esmaeili Ghayoumabadi v.v.Cheverikin A.v.Mikhaylovskaya National University of Sciences and Technology“MISIS” 119049Leninskiy Ave.4MoscowRussia Prokhorov General Physics Institute of the Russian Academy of Sciences MoscowRussia

Dispersoid hardening is a key factor in increasing the recrystallization resistance and mechanical strength of non-heat treatable aluminum-based *** and Zr are the main elements that form dispersoids in commercial Al-based *** this work,the annealing-induced precipitation behavior,the grain structure,and the mechanical properties of Al-3.0 Mg-1.1 Mn and Al-3.0 Mg-1.1 Mn-0.25 Zr alloys were *** microstructure and the mechanical properties were significantly affected by annealing regimes after casting for both *** research demonstrated a possibility to form high-density distributed quasicrystalline-structured I-phase precipitates with a mean size of 29 nm during low-temperature annealing of as-cast *** manganese-bearing precipitates of I-phase increased recrystallization resistance and significantly enhanced the mechanical strength of the alloys *** estimated strengthening effect owing to I-phase precipitation was 150 *** to the formation of L1_(2)-structured Al3Zr dispersoids with a mean size of 5.7 nm,additional alloying with Zr increased yield strength by about 90 *** L1_(2)-phase strengthening effect was estimated through the dislocation bypass looping and shearing mechanisms.

关键词： Aluminum alloy Quasicrystals Dispersoid hardening Recrystallization Mechanical properties

Diffusion in the aged aluminium film on iron

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Chinese Physics B 2017年第3期26卷 569-574页

作者： A Y Galashev O R Rakhmanova v A Kovrov yu P Zaikov Institute of High-Temperature Electrochemistry Ural Branch of Russian Academy of Sciences Yekaterinburg 620990 Russia

Metallic coatings of many types can be applied to steel to provide outstanding, long-term corrosion protection. A thin A1 film is studied at an Fe substrate by the molecular dynamics method at temperatures ranging from 300 K to 1173 K. A1 atoms are found to penetrate the Fe matrix at a temperature of 873 K. The potential energy of the system changes step-like at a temperature of 1173 K. At such temperature mean square atomic displacement significantly changes. The behaviors of the A1 and Fe diffusion coefficients are mainly determined by the temperature dependence of the diffusion activation energy.

关键词： aluminium film diffusion coefficients iron molecular dynamics

vanadium-doped TiO_(2)-B/anatase mesoporous nanotubes with improved rate and cycle performance for rechargeable lithium and sodium batteries

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Journal of Materials Science & Technology 2020年第19期54卷 181-189页

作者： D.P.Opra S.v.Gnedenkov A.A.Sokolov A.B.Podgorbunsky A.yu.Ustinov v.yu.Mayorov v.G.Kuryavyi S.L.Sinebryukhova Institute of Chemistry FEB RAS 159Pr.100-letiya Vladivostok1Vladivostok 690022Russia Far Eastern Federal University 8St.Sukhanov1Vladivostok 690950Russia

TiO_(2)-B/anatase nanotubes doped by vanadium have been synthesized through a facile one-step hydrothermal *** material shows a mesoporous structure with a specific surface area of 179.1 m^(2)g^(-1).XPS data presume the presence of v^(3+),v^(4+),v^(5+),and Ti^(3+) in doped TiO2-B/*** found by XRD and EIS investigations,the vanadium expands bronze titania crystal structure and enhances the conductivity of material by three orders of *** tested for lithium storage,the v-modified titania nanotubes show a specific capacity of 133 mA h g^(-1) after 100 charge/discharge cycles at the current density of 3000 mA g^(-1) with a Coulombic efficiency of around 98.9%,resulting in its good *** material still possesses a reversible capacity of 114 mA h g^(-1) at a very high current load of 6000 mA g^(-1),demonstrating superior rate characteristics for secondary lithium ***,v-doped Ti O2-B/anatase mesoporous nanotubes show promise performance as anode material for sodium-ion batteries,delivering about 119 mA h g^(-1) and 101 m A h g^(-1) at the current loads of 10 and 1500 m A g^(-1),respectively.

关键词： Lithium-ion battery Sodium-ion battery Anode TiO_(2)-B Anatase Doping Nanotubes Mesoporosity

First-principles study of the local structure and crystal field of Yb^(2+) in sodium and potassium halides

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Chinese Physics B 2012年第3期21卷 349-354页

作者：闻军段昌奎尹民 yu.v.Orlovskii 夏上达章永凡 Department of Physics University of Science and Technology of China Prokhorov General Physics Institute RAS 38 Vavilov st.Moscow 119991Russia Institute of Physics University of TartuRiia 142Tartu 51014Estonia Department of Chemistry Fuzhou University

The local coordination structures around the doping Yb2＋ ions in sodium and potassium halides were calculated by using the first-principles supercell model. Both the cases with and without the charge compensation vacancy in the local environment of the doping Yb2＋ were calculated to study the effect of the doping on the local coordination structures of Yb2＋. Using the calculated local structures, we obtained the crystal-field parameters for the Yb2＋ ions doped in sodium and potassium halides by a method based on the combination of the quantum-chemical calculations and the effective Hamiltonian method. The calculated crystal-field parameters were analyzed and compared with the fitted results.

关键词： sodium and potassium halides local coordination structure distortion crystal-field parameters

Microbe social skill:the cell-to-cell communication between microorganisms

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Science Bulletin 2017年第7期62卷 516-524页

作者： Xi Zhao Xiong Liu Xin Xu yu v.Fu State Key Laboratory of Microbial Resources Institute of MicrobiologyChinese Academy of Sciences Savaid Medical School University of Chinese Academy of Sciences

Although microbes primarily are single-cell organisms,they are not isolated *** use various means to communicate with one *** on the communication,microbes establish a social interaction with their neighbors in a specific ecological niche,and cooperative behaviors are normally performed to provide benefits on the population and species *** the microbiome era,in order to better understand the behaviors of microbes,deep understanding of the social communication between microbes hence becomes a key to interpret microbe *** we summarize the molecular mechanisms that underlie the cell-to-cell communication in prokaryotic and eukaryotic microorganisms,the recent discoveries and novel technologies in understanding the interspecies and interkingdom communication,and discuss new concepts of the sociomicrobiology.

关键词： Cell-to-cell communication Sociomicrobiology Microbial collective behavior Quorum sensing

Nonlinear dynamics of MEMS turning fork gyroscope

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Science China(Technological Sciences) 2011年第5期54卷 1078-1083页

作者： yu. G. MARTYNENKO I. v. MERKURYEv v. v. PODALKOv Institute of Mechanics Lomonosov Moscow State University Moscow Power Engineering Institute (Technical University)

Accuracy improvement of MEMS gyros requires not only microelectronic development but also the investigations of th mathematical model of sensitive element dynamics. In the present paper, we study the errors of the vibrating microgyroscop which arise because of nonlinear dynamics of a sensitive element. A MEMS tuning fork gyroscope with elastic rods is consid ered. Nonlinear differential equations of bending vibrations of sensitive element on the moving basis are derived. Free nonlin ear vibrations of gyroscopes as the flexible rod are studied. Nonlinear dynamics of gyroscope on the moving basis are investi gated by asymptotic two scales method. Sensitive element frequencies split on two frequencies resulted from slowly changin angular velocity are taken into account in the equations of zero approximation. The differential equations for slowly changin amplitudes and phases of two normal waves of the oscillations measured by capacitor gauges and an electronic contour of th device are obtained from the equations of the first approximation.

关键词： control of gyro oscillations split of frequencies identification averaging method two scales method stability

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))ven 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))ver 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

Determining absolute value of thermal neutron flux density based on monocrystalline silicon in nuclear reactors

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Nuclear Science and Techniques 2022年第7期33卷 133-138页

作者： v.A.varlachev E.G.Emets yu-Chen Mu E.A.Bondarenko v.A.Govorukhin National Research Tomsk Polytechnic University Tomsk634050Russia

A new type of neutron detector based on monocrystalline Si is developed to measure the fluence and flux density of thermal and fast *** principle of this detector is based on the relationship between changes in electrical conductivity and neutron fluence during ***,the absolute values of thermal neutron fluence and flux density are measured in a facile manner with high *** with activation methods,our method not only possesses a similar accuracy,but also demonstrates superior application potential for the investigation of neutron fields in nuclear reactors owing to its suitable half-life.

关键词： Thermal neutron Neutron detector Neutron flux density Cadmium difference methods

Electron-beam Treatment of Tungsten-free TiC/NiCr CermetⅡ: Structural Transformations in the Subsurface Layer

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Journal of Materials Science & Technology 2006年第4期22卷 511-513页

作者： Baohai yu v.E.Ovcharenko S.G.Psakhie O.v.Lapshin Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Institute of Strength Physics and Materials Science Siberia Branch Russian Academy of Sciences Russia

The character of structural changes in the surface layer of titanium carbide （TiC） with Ni-Cr alloy binder was investigated theoretically and experimentally after electron-beam treatment of the material surface. The thermal influence of the electron-beam irradiation on the surface layer microstructure of the composite fine-grained material was mathematically analyzed. Quantitative estimations of the depth of the zone in microstructural phase transformations were carried out. The microstructure and concentration profile of Ti distribution in the metallic binder over the cross section of the surface layer with microstructural phase transformations after electron-pulse treatment of the hard metal surface were experimentally investigated.

关键词： Cermets TiC/NiCr Electron-beam treatment Structural transformation