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Chinese Optics Letters 2023年第3期21卷 113-117页

作者： Igor Kinyaevskiy valeri Kovalev Pavel Danilov Nikita smirnov Sergey Kudryashov Andrey Koribut Andrey Ionin P.N.Lebedev Physical Institute of the Russian Academy of Sciences Moscow 119991Russia

An exceptionally high stimulated Raman scattering[SRS]conversion efficiency to the first Stokes component associated with the secondary[low-frequency and low intensity]vibrational mode v2[~330 cm^[-1]]was observed in a BaWO4 crystal in a highly transient regime of *** effect takes place in the range of pump pulse energy from~0.1 to~0.5μJ with maximum energy conversion efficiency up to 35%at 0.2μ*** nature of the observed effects is explained by interference of SRS and self-phase modulation,where the latter is related to a noninstantaneous orientational Kerr nonlinearity in the BaWO4 crystal.

关键词： stimulated Raman scattering secondary vibrational mode self-phase modulation ultrashort laser pulses transient phenomena

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

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

Stability of Macroscopic Binary Systems

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Communications in Theoretical Physics 2019年第11期71卷 1335-1340页

作者： G.G.Adamian N.v.Antonenko H.Lenske v.v.Sargsyan Joint Institu te for Nuclear Research 141980 DubnaRussia Ins titut fur Theore tische Physik der Jus tus-Liebig—Uni versit Nt D-35392 GiessenGermany

The Darwin instability effect in the binary systems(di-planets, di-stars, and di-galaxies) is analyzed within the model based on the Regge-like laws. All possible binary stars are found satisfying the Darwin instability condition that requires to search for other mechanism triggering the merger of the contact binary objects. New analytical formulas are obtained for the orbital rotation period and the relative distance between components of the binary system. The decreasing and increasing periods as functions of mass asymmetry are related, respectively, with the non-overlapping and overlapping stage of the binary object evolution.

关键词： Regge laws binary stars and galaxies Darwin instability effect

Abrasion of ultrafine WC-Co by fine abrasive particles

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中国有色金属学会会刊：英文版 2007年第6期17卷 1287-1293页

作者： P. v. Krakhmalev Department of Mechanical and Materials Engineerin g Karlstad University SE-651 88 Karlstad Sweden

Abrasive wear of a series of WC-(5%-14%, mass fraction)Co hardmetals was investigated employing coarse and fine SiC abrasive under two-body dry abrasion conditions with pin-on-disc and edge-on-disc test arrangements. Unexpectedly, it is found that submicron grades demonstrate substantially higher wear rates comparing with the coarse grades if fine abrasive is utilized in pin-on-disc tests. Such a behavior is attributed to changes in a ratio of abrasive size to size of hard phase as finer abrasive is used. The edge-on-disc test demonstrates that edge wear may be described in two stages with the highest wear rates at the beginning stage. This behavior is associated with a transition of wear mechanisms as edge is wider due to wear. Compared with the ultrafine grades of the same Co content, the coarse grades demonstrate higher wear rates at the beginning, but lower wear rates at the final stage. Wear rates and mechanisms observed at final stage correlate well to the results observed for pin-on-disc tests employing fine abrasive.

关键词： WC-Co合金耐磨性边缘磨损微观效应

Effect of MWCNT reinforcement on the precipitation-hardening behavior of AA2219

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International Journal of Minerals,Metallurgy and Materials 2018年第1期25卷 53-61页

作者： Shijo Thomas Umasankar v. School of Mechanical and Building Sciences VIT University

Aluminum alloy matrix composites have found a predominant place in research, and their applications are explored in almost all industries. The aerospace industry has been using precipitation-hardenable alloys in structural applications. However, insufficient literature is available on the influence of multiwalled carbon nanotubes （MWCNTs） on precipitation-hardenable alloy composite materials; thus, this work was designed to elucidate the effect on MWCNT reinforcement on AA2219 with and without precipitation hardening. Reinforcement with MWCNTs has been reported to accelerate precipitation and to achieve greater hardness within a much shorter time. The addition of 0.75wt% MWCNTs resulted in maximal hardness at 90 min, which is approximately 27% of improvement over the maximum hardness achieved by the corresponding monolithic alloy after 10 h of aging. The sample reinforced with 0.75wt% MWCNTs showed an improve- ment of 82% in hardness by solutionizing and aging compared to that achieved by sintering.

关键词： aluminum metal-matrix composites multi walled carbon nanotubes (MWCNT) powder metallurgy heat treatment precipitation hardening

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

Influence of Small-Size Contaminations on Thin Film Structural Properties

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Chinese Physics Letters 2019年第3期36卷 82-85页

作者： F.v.Grigoriev v.B.Sulimov Jinlong Zhang Xinbin Cheng Zhanshan Wang A.v.Tikhonravov Research Computing Center M.V.Lomonosov Moscow State University MOE Key Laboratory of Advanced Micro-Structured Materials Institute of Precision Optical Engineering School of Physics Science and EngineeringTongji University IFSA Collaborative Innovation Center Shanghai Jiao Tong University

An approach for studying the influence of nano-particles on the structural properties of deposited thin films is proposed. It is based on the molecular dynamic modeling of the deposition process in the presence of contaminating nano-particles. The nano-particle is assumed to be immobile and its interaction with film atoms is described by a spherically symmetric potential. The approach is applied to the investigation of properties of silicon dioxide films. visualization tools are used to investigate the porosity associated with nano-particles. The structure of the film near the nano-particle is studied using the radial distribution function. It is found that fluctuations of film density near the nano-particles are essentially different in the cases of low-energy and high-energy deposition processes.

关键词： Influence Small-Size Properties

Dopaminergic mediation in the brain aging and neurodegenerative diseases:a role of senescent cells

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Neural Regeneration Research 2018年第4期13卷 649-650页

作者： Pavel v.Nekrasov vasily v.vorobyov Institute of Cell Biophysics Russian Academy of Sciences

Aging is well known to be the main risk factor for the neurodegenerative pathologies,in particular,Parkinson’s disease（PD）and Alzheimer’s disease（AD）.In aging and in the diseases,similar changes in various hallmarks of neurodegeneration（lipofuscin accumulation,autophagia weakening,and disturbances in functions of mitochondriaand lysosomes） were shown （Tan et al., 2014）. Furthermore, dopami- nergic system （DAS） involvement in mechanisms of aging, PD, and AD were revealed （Martorana and Koch, 2014）.

关键词： Dopaminergic mediation in the brain aging and neurodegenerative diseases:a role of senescent cells

Age of maturation and behavioral tactics in male yellow ground squirrel Spermophilus fulvus during mating season

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Current Zoology 2014年第6期60卷 700-711页

作者： Nina A. vASILIEvA Ekaterina v. PAvLOvA Sergey v. NAIDENKO Andrey v.TCHABOvSKY A.N. Severtsov Institute of Ecology and Evolution Russian Academy of Sciences 33 Leninsky pr. Moscow 119071 Russia

Life-history theory predicts that in hibemators age of maturation is related positively to body size and negatively to the duration of active season aboveground. Yellow souslik is a large-sized ground squirrel with long hibernation, which suggests late maturation. We used four-year field observations of marked individuals to determine the age of maturation in males through analysis of age-dependent variation in body size, mass, androgen status, timing of spring emergence, ranging patterns and social behavior during the mating season. Yearling males were smaller, lighter, had lower level of fecal testosterone, emerged later and had smaller home ranges than older males. Social activity and the number of females encountered did not differ between age classes. After the second hibernation none of the studied parameters varied with age. Cluster analysis revealed two behavioral tactics：＂active＂ males （adults only） emerged earlier, ranged more widely, initiated more contacts, encountered more females and were heavier than ＂passive＂ males （both yearling and adult）. Thus, males of S. fulvus reached adult size and matured after two hibernations, which is relatively fast for such a big species with short active period. Indirect evidence for copulations and high variation among yearlings in all parameters suggest that some of them might successfully compete with adults. Active tactic of wandering and searching for females is energetically costly, and probably only adult males in good physical condition can afford it, whereas passive tactic of residing is energy saving and good for adults in poor condition and for yearlings that are continuing to grow.

关键词： Age of maturation Mating system Reproductive tactics Ground squirrel Spermophilusfulvus