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STRESS-STRAIN STATE OF ELASTOPLASTIC BODIES WITH CRACK

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Acta Mechanica Solida Sinica 2015年第4期28卷 375-383页

作者： v.v.Glagolev L.v.Glagolev A.A.Markin Tula State University

A physical cut model is used to describe the changes in the stress-strain state （SSS） in elastoplastic bodies weakened by cracks. The distance between the crack edges is considered to be finite in contrast to the mathematical cut. The interactive layer with a thickness limited by the possibility of using the hypothesis of continuity is distinguished on the physical cut extension, Distribution of stresses and strains over the layer thickness is constant and does not depend on the geometry of the boundary between the cut and the interactive layer. The relationship between stresses and strains is determined by the deformation plasticity theory. The problem of plane strain or plane stress state of an arbitrary finite body weakened by a physical cut is reduced to solving a system of two variational equations for displacement fields in the body parts adjacent to the interactive layer. The proposed approach eliminates the singularity in stress distribution in contrast to the mathematical cut model. Use of local strength criteria allows us to determine the time, point and direction of the fracture initiation. Possibilities of the proposed model are illustrated by solving the problems of determining the SSS of a rectangular body weakened by a physical cut under symmetric and antisymmetric loadings.

关键词： crack physical cut characteristic size elastoplastic deformations

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

Synthesis of MoO_3 by glow discharge in contact with water

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Plasma Science and Technology 2019年第2期21卷 97-104页

作者： A v KHLYUSTOvA N A SIROTKIN A S KRAYEv v A TITOv A v AGAFONOv Laboratory of Chemistry of Carbohydrate Coordination Compounds and Supermolecular System G.A.Krestov Institute of Solution Chemistry of RAS

An atmospheric pressure glow discharge was ignited between a molybdenum anode and the water surface of a cathode for the synthesis of MoO_3 powders. The action of glow discharge leads to the non-equilibrium evaporation of water, sputtering of the metal anode and formation of molybdenum(vI) oxide, which deposited on the anode. The chemical composition and morphology of the obtained powder were performed by using x-ray diffraction spectroscopy,scanning electron microscopy and Fourier transform infrared spectroscopy. It was found that the synthesized powders are pure α-MoO_3. The possible mechanism of the formation of molybdenum trioxide during glow discharge treatment was described. The photocatalytic performance of MoO_3 was estimated through the degradation of Rhodamine B under dark and Uv irradiation conditions. Orthorhombic MoO_3 exhibited the best photocatalytic activity for the photodegradation of Rhodamine B of 100% under Uv irradiation for 15 min.

关键词： molybdenum oxide glow discharge photocatalytic activity

Incubation time approach in rock fracture dynamics

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 78-85页

作者： SMIRNOv v PETROv Yuri v BRATOv v St.-Petersburg State Transport University 198103 St.-Petersburg Russia St.-Petersburg State University 198504 St.-Petersburg Russia Institute of Problems of Mechanical Engineering Russian Academy of Sciences 199178 St.-Petersburg Russia

The paper is summarizing latest results connected with application of the incubation time approach to problems of dynamic fracture of rock materials. Incubation time based fracture criteria for intact media and media with cracks are discussed. Available experimental data on high rate fracture of different rock materials and incubation time based fracture criteria are used in order to evaluate critical parameters of causing fracture in these materials. Previously discovered possibility to optimize (minimize) energy input for fracture is discussed in connection to industrial rock fracture processes. It is shown that optimal value of momentum associated with critical load in order to initialize fracture in rock media does strongly depend on the incubation time and the impact duration. Existence of optimal load shapes minimizing momentum for a single fracturing impact or a sequence of periodic fracturing impacts is demonstrated.

关键词： incubation time dynamic fracture rocks dynamic strength fracture toughness crack resistance energy and momentum input fracture process optimization

Arctic source for elevated atmospheric mercury(Hg^0) in the western Bering Sea in the summer of 2013

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Journal of Environmental Sciences 2018年第6期30卷 114-121页

作者： v.v.Kalinchuk v.F.Mishukov A.S.Astakhov v.I.Il'ichev Pacific Oceanological Institute of Far Eastern Branch of Russian Academy of Sciences Vladivostok Russia

Measurements of gaseous elemental mercury（Hg^0） in the marine boundary layer of the western Bering Sea were performed using an automatic mercury analyzer RA 915 ＋（Ltd. ＂Lumex＂, St. Petersburg, Russia） aboard the Russian research vessel Academician *** from 3 to 20 August 2013. Hg^0 concentrations varied from 0.3 to 2.1 ng/m^3（n = 4783）;the average value（1.1 ± 0.3 ng/m^3） was lower than both the background range of the Northern Hemisphere（1.5–1.7 ng/m^3） and average values previously observed in the Bering Sea, and corresponded to the background concentrations of the Southern Hemisphere（1.1–1.3 ng/m^3）.Maximum Hg^0 concentrations were observed within air masses that came from the lower troposphere of the central Arctic. Under these conditions, Hg^0 ranged between 1.1 and 2.1 ng/m^3 with an average of 1.5 ± 0.2 ng/m^3（n = 1183）. Except for these periods, Hg^0 concentrations during the rest of the study varied from 0.3 to 1.8 ng/m^3, with an average value of 1.0 ± 0.2 ng/m^3（n = 3600）. Our results support the hypothesis that, in the summer, air masses from the central Arctic Ocean can be an exporter of mercury to lower latitudes. Perhaps the atmospheric transport of elevated concentrations of Hg^0 into lower latitudes may have implications for the biologic and economic health of important fisheries, such as the Bering Sea.

关键词： Mercury Atmosphere Long-range transport Bering Sea Arctic

The effect of forced oscillations on the kinetics of wave drift in an inhomogeneous plasma

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Plasma Science and Technology 2020年第12期22卷 8-19页

作者： v I EROFEEv Institute of Automation&Electrometry of the Siberian Branch of the Russian Academy of Sciences 1 Koptyug Prosp.630090NovosibirskRussia Novosibirsk State University 2 Pirogova Str.NovosibirskRussia

The kinetics is analyzed of the drift of non-potential plasma waves in spatial positions and wavevectors due to plasma's spatial inhomogeneity. The analysis is based on highly informative kinetic scenarios of the drift of electromagnetic waves in a cold ionized plasma in the absence of a magnetic field(Erofeev 2015 Phys. Plasmas 22 092302) and the drift of long Langmuir waves in a cold magnetized plasma(Erofeev 2019 J. Plasma Phys. 85 905850104). It is shown that the traditional concept of the wave kinetic equation does not account for the effects of the forced plasma oscillations that are excited when the waves propagate in an inhomogeneous *** are highlighted that account for these oscillations in the kinetic equations of the abovementioned highly informative wave drift scenarios.

关键词： informativeness of plasma kinetic scenario the ensemble method asymptotic convergence of perturbation theories correlation analysis of plasma kinetics kinetic equation of wave drift in phase space

Ordered exponential and its features in Yang-Mills effective action

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Communications in Theoretical Physics 2023年第8期75卷 119-127页

作者： A v Ivanov N v Kharuk St.Petersburg Department of Steklov Mathematical Institute of Russian Academy of Sciences 27 FontankaSt.Petersburg 191023Russia Leonhard Euler International Mathematical Institute 10 Pesochnaya nab.St.Petersburg 197022Russia

In this paper,we discuss some non-trivial relations for ordered exponentials on smooth Riemannian *** an example of application,we study the dependence of the four-dimensional quantum Yang–Mills effective action on the special gauge transformation with respect to the background ***,we formulate some open questions about a structure of divergences for a special type of regularization in the presence of the background field formalism.

关键词： Yang-Mills effective action ordered exponential heat kernel Green's function short-distance asymptotics cutoff regularization Synge's world function

Hydrothermal Hgbomite Associated with vanadiferous-Titaniferous(v-Ti) Bearing Magnetite Bands in Bhakatarhalli Chromite Mine, Nuggihalli Greenstone Belt, Western Dharwar Craton, Karnataka, India

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Acta Geologica Sinica(English Edition) 2014年第3期88卷 845-853页

作者： Raju v.S.PERUMALA Roland K.W.MERKLE National Geophysical Research Institute PO Box 724 Hyderabad India (Council of Scientific and Industrial Research) Department of Geology University of Pretoria

Hogbomite,a rare exotic mineral,is found to be associated with the vanadiferous-titaniferous （v-Ti） bearing magnetite bands at Bhakatarhalli,Nuggihaifi greenstone belt,western Dharwar Craton,*** report on a second occurrence of hogbomite from the Dharwar craton in Karnataka,which is the sixth documented occurrence of this mineral from *** evaluate the chemical characteristics of hogbomite and associated Fe-Ti-minerals in an attempt to identify its formation as a primary hydrothermal mineral in a metamorphosed magnetite *** report here the presence of hogbomite as a complex oxide of Fe,Mg,Al and Ti with accessory of Zn,v and *** studies suggest the （v-Ti） bearing magnetite （Mt） contain spinel,hogbomite,chlorite,martite,ilmenite （Ⅱ） and minor amounts of *** hogbomite displays euhedral to subhedral textures,and is up to 250 μm along the grain boundaries of magnetite and *** the samples studied,hogbomite is prismatic,irregular and elongated in *** genesis of hogbomite in veins between magnetite and ilmenite implies its precipitation from fluids without involving complicated *** models were proposed for the formation of hogbomite; however,the subject is still debatable.

关键词： Hogbomite western Dharwar craton vanadium magnetite EPMA India

Fabrication and characterization of Ti6A14v/TiB2-TiC composites by powder metallurgy method

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Rare Metals 2017年第10期36卷 806-811页

作者： M. Anandajothi S. Ramanathan v. Ananthi P. Narayanasamy Department of Manufacturing Engineering Annamalai University Chidambaram Tamil Nadu 608 002 India Physics Section Faculty of Engineering and Technology Annamalai University Chidambaram Tamil Nadu 608 002 India Department of Mechanical Engineering Kamaraj College of Engineering and Technology Virudhunagar Tamil Nadu 626 001 India

Titanium matrix （Ti6Al4v） composites rein- forced with TiB2 and TiC were produced through powder metallurgy method. The effect of addition of both TiB2 and TiC with different contents （2.5 wt%, 5.0 wt% and 7.5 wt%） on the density, microstructure and hardness properties of titanium matrix was investigated. The size distributions of the matrix alloy and reinforcement particles were measured by particle size analyzer. Microhardness of the sintered composites was evaluated using vickers＇s hardness tester with a normal load of 3 N and a dwell time of 10 s. Ti6Al4v alloy and Ti6Al4v/TiB2-TiC composites were characterized through X-ray diffraction （XRD） and field emission scanning electron microscope （FESEM） equipped with energy-dispersive spectrometer （EDS）. The addition of TiB2 and TiC particles enriches the properties of Ti6Al4v alloy. The sintered Ti6Al4v/TiB2-TiC composite features a dense and pore-free microstructure with varying TiB2 and TiC particle distribution in the metal matrix. The results of this study show that the development of new phases plays a significant role in the properties of these composite materials.

关键词： Ti6Al4v TiB2 TiC Microstructure