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Journal of Materials Science & Technology 2005年第3期21卷 427-429页

作者： v.e.Ovcharenko BaohaiYU S.G.Psakhie InstituteofStrengthPhysicsandMaterialsScience SiberiaBranchRussianAcademyofSciences2/1AcademicheskyPr.Tomsk634021Russia InstituteofMetalResearch ChineseAcademyofSciences72WenhuaRoadShenyang110016China

An experimental investigation were performed on the effect of the impulse electron-beam irradiation upon microstruc-ture of the surface layer and on wear resistance of a cutting tool for sintered TiC/NiCr cermet. The results showed that the surface electron-beam treatment of the TiC/NiCr cermet is an efficient method for investigating the mi-crostructure and phase composition in the surface layer of the powder composite and there are optimal regimes of electron-beam treatment, which ensure a substantial increase in the resistance of the cermet to wear during cutting of metals.

关键词： Cermet TiC/NiCr electron-beam treatment Microstructure Wear resistance

Gate-Dependent Nonlinear Hall effect at Room Temperature in Topological Semimetal GeTe

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Chinese Physics Letters 2023年第7期40卷 63-67页

作者： N.N.Orlova A.v.Timonina N.N.Kolesnikov e.v.Deviatov Institute of Solid State Physics of the Russian Academy of Sciences ChernogolovkaMoscow District2 Academician Ossipyan str.142432Russia

We experimentally investigate nonlinear Hall effect as zero-frequency and second-harmonic transverse voltage responses to ac electric current for topological semimetal GeTe.A thick single-crystal GeTe flake is placed on the Si/SiO_(2) substrate,where the p-doped Si layer serves as a gate *** confirm that electron concentration is not gate-sensitive in thick GeTe flakes due to the gate field screening by bulk *** contrast,by transverse voltage measurements,we demonstrate that the nonlinear Hall effect shows pronounced dependence on the gate electric field at room *** the nonlinear Hall effect is a direct consequence of a Berry curvature dipole in topological media,our observations indicate that Berry curvature can be controlled by the gate electric *** experimental observation can be understood as a result of the known dependence of giant Rashba splitting on the external electric field in *** possible applications,the zero-frequency gate-controlled nonlinear Hall effect can be used for the efficient broad-band rectification.

关键词： temperature. field. curvature

Understanding the mechanisms of friction stir welding based on computer simulation using particles

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Defence Technology（防务技术） 2018年第6期14卷 643-656页

作者： A.Yu.Smolin e.v.Shilko S.v.Astafurov e.A.Kolubaev G.M.eremina S.G.Psakhie Institute of Strength Physics and Materials Science SB RAS Tomsk634055Russia Tomsk State University Tomsk634050Russia Skolkovo Institute of Science and Technology Skolkovo143025Russia

Friction stir welding(FSW) is a novel technique for joining different materials without melting. In FSW the welded components are joined by stirring the plasticized material of the welded edges with a special rotating pin plunged into the material and moving along the joint line. From the scientific point of view,the key role of the FSW processes belongs to formation of the special plasticized conditions and activation of physical mechanisms of mixing the materials in such conditions to produce the strong homogeneous weld. But it is still a lack of complete understanding of what are these conditions and *** paper is devoted to understanding the mechanisms of material mixing in conditions of FSW based on a computer simulation using particles. The movable cellular automaton method(MCA), which is a representative of the particle methods in mechanics of materials, was used to perform all ***, material flow including material stirring in FSW is simulated using computational fluid mechanics or smoothed particle hydrodynamics, which assume that the material is a continuum and does not take into account the material structure. MCA considers a material as an ensemble of bonded particles. Breaking of inter-particle bonds and formation of new bonds enables simulation of crack nucleation and healing, as well as mass mixing and *** paper consists of two main parts. In the first part, the simulations in 2 D statements are performed to study the dynamics of friction stir welding of duralumin plates and influence of different welding regimes on the features of the material stirring and temperature distribution in the forming welded joints. It is shown that the ratio of the rotational speed to the advancing velocity of the tool has a dramatic effect on the joint quality. A suitable choice of these parameters combined with additional ultrasonic impact could considerably reduce the number of pores and microcracks in the weld without significa

关键词： Friction stir welding Plastic flow Deformation mechanisms Simulation Particle method

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

Generalized quantum mechanical two-Coulomb-center problem (Demkov problem)

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Chinese Physics B 2013年第9期22卷 245-251页

作者： A.M.Puchkov A.v.Kozedub e.O.Bodnia Theoretical Department Institute of PhysicsSt. Petersburg State University Department of Computational Physics Faculty of PhysicsSt. Petersburg State University

We present a new exactly solvable quantum problem for which the Schrtidinger equation allows for separation of variables in oblate spheroidal coordinates. Namely, this is the quantum mechanical two-Coulomb-center problem for the case of an imaginary intercenter parameter and complex conjugate charges are considered. Since the potential is defined by the two-sheeted mapping whose singularities are concentrated on a circle rather than at separate points, there arise additional possibilities in the choice of boundary conditions. A detailed classification of the various types of boundary-value problems is given. The quasi-radial equation leads to a new type of boundary value problem which has never been considered before. Results of the numerical calculations, which allow conclusions to be drawn about the structure of the energy spectrum, are shown. Possible physical applications are discussed.

关键词： two-Coulomb-center problem potential models

Indentation of elastically soft and plastically compressible solids

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Acta Mechanica Sinica 2015年第4期31卷 473-480页

作者： A.Needleman v.Tvergaard e.van der Giessen Department of Materials Science and engineering Texas A&M University College Station Department of Mechanical engineering The Technical University of Denmark Zernike Institute for Advanced Materials University of Groningen

The effect of soft elasticity, i.e., a relatively small value of the ratio of Young＇s modulus to yield strength and plastic compressibility on the indentation of isotropically hardening elastic-viscoplastic solids is investigated. Calcu- lations are carried out for indentation of a perfectly sticking rigid sharp indenter into a cylinder modeling indentation of a half space. The material is characterized by a finite strain elastic-viscoplastic constitutive relation that allows for plas- tic as well as elastic compressibility. Both soft elasticity and plastic compressibility significantly reduce the ratio of nomi- nal indentation hardness to yield strength. A linear relation is found between the nominal indentation hardness and the log- arithm of the ratio of Young＇s modulus to yield strength, but with a different coefficient than reported in previous studies. The nominal indentation hardness decreases rapidly for small deviations from plastic incompressibility and then decreases rather slowly for values of the plastic Poisson＇s ratio less than 0.25. For both soft elasticity and plastic compressibility, the main reason for the lower values of indentation hardness is related to the reduction in the hydrostatic stress level in the material below the indenter.

关键词： Plasticity Compressibility Indentation Finite element analysis

Numerical forecasting surge in a piping of compressor shops of gas pipeline network

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2007年第11期8卷 1775-1788页

作者： SeLeZNev v. e. PRYALOv S. N. Physical & Technical Center Joint Stock Company Sarov 607180 Russia

This paper presents a method of forecasting stable operation of gas compressor unit (GCU) centrifugal supercharger (CFS) installed on a piping of compressor shops servicing gas pipelines. The stability of superchargers operation is assessed in relation to the phenomenon of surge. Solution of this problem amounts to the development and numerical analysis of a set of ordinary differential equations. The set describes transmission of gas through a compressor shop as a fluid dynamics model with lumped parameters. The proposed method is oriented to wide application by specialists working in the gas industry. The practical application of this method can use all-purpose programming and mathematical software available to specialists of gas companies.

关键词： Gas pipelines Compressor station Centrifugal supercharger (CFS) Surge Numerical simulation

Restructuring of plasmonic nanoparticle aggregates with arbitrary particle size distribution in pulsed laser fields

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Chinese Physics B 2016年第11期25卷 563-570页

作者： A e ershov A P Gavrilyuk S v Karpov S P Polyutov Institute of Computational Modeling Russian Academy of SciencesKrasnoyarsk 660036Russia L.v.Kirensky Institute of Physics of the Russian Academy of Sciences Krasnoyarsk 660036Russia Siberian Federal University Krasnoyarsk 660028Russia Siberian State Aerospace University Krasnoyarsk 660037Russia

We have studied processes of interaction of pulsed laser radiation with resonant groups of plasmonic nanoparticles（resonant domains） in large colloidal nanoparticle aggregates having different interparticle gaps and particle size *** processes are responsible for the origin of nonlinear optical effects and photochromic reactions in multiparticle *** describe photo-induced transformations in resonant domains and alterations in their absorption spectra remaining after the pulse action,we introduce the factor of spectral *** on calculation of changes in thermodynamic,mechanical,and optical characteristics of the domains,the histograms of the spectrum photomodification factor have been obtained for various interparticle gaps,an average particle size,and the degree of *** in spectra have been analyzed depending on the intensity of laser radiation and various combinations of size characteristics of *** obtained results can be used to predict manifestation of photochromic effects in composite materials containing different plasmonic nanoparticle aggregates in pulsed laser fields.

关键词： resonant arbitrary pulsed dipole manifestation alterations extinction remaining aggregate colloidal

The multi-impurity system in CdSe nanoplatelets:electronic structure and thermodynamic properties

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Communications in Theoretical Physics 2024年第3期76卷 165-173页

作者： D A Baghdasaryan v A Harutynyan e M Kazaryan H A Sarkisyan Russian-Armenian University H Emin 1230051YerevanArmenia Institute of Applied Problems of Physics 25 Nersisyan St0014YerevanArmenia

This paper theoretically studies the impurity states and the effects of impurity concentration and configuration on the optical,electrical,and statistical properties of CdSe nanoplatelets(NPLs).An image charge-based model of electron-impurity interaction is *** charge-carrier energy spectra and corresponding wave functions depending on the impurity number and configuration are *** electron binding energies are calculated for different NPL *** is shown that the image charge-based interaction potential that arises due to the dielectric constants mismatch is much stronger than the interaction potential that does not take such a mismatch into ***,it is demonstrated that the binding energies are increasing with the number of *** calculate the canonical partition function using the energy levels of the electron,which in turn is used to obtain the mean energy,heat capacity,and entropy of the non-interacting electron *** thermodynamic properties of the non-interacting electron gas that depend on the geometric parameters of the NPL,impurity number,configuration,and temperature are studied.

关键词： nanoplateletes thermodynamic properties impurity states

Theoretical and experimental Study on the Adsorption and Desorption of Methane by Granular Activated Carbon at 25℃

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Journal of Natural Gas Chemistry 2007年第4期16卷 415-422页

作者： e.Salehi v.Taghikhani C.Ghotbi e.Nemati Lay A.Shojaei Department of Chemical and Petroleum engineering Sharif University of Technology TehranIran

A theoretical and experimental study was conducted to accurately determine the amount of adsorption and desorption of methane by various Granular Activated Carbon （GAC） under different physical conditions. To carry out the experiments, the volumetric method was used up to 500 psia at constant temperature of 25℃. In these experiments, adsorption as well as desorption capacities of four different GAC in the adsorption of methane, the major constituent of natural gas, at various equilibrium pressures and a constant temperature were studied. Also, various adsorption isotherm models were used to model the experimental data collected from the experiments. The accuracy of the results obtained from the adsorption isotherm models was compared and the values for the regressed parameters were reported. The results shows that the physical characteristics of activated carbons such as BeT surface area, micropore volume, packing density, and pore size distribution play an important role in the amount of methane to be adsorbed and desorbed.

关键词： methane adsorption volumetric method activated carbon two-term TvFM isotherm