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Ricci Collineations of Static Space Tim.s with m.xim.l Sym.etric Transverse Spaces

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Com.unications in Theoretical Physics 2006年第1期45卷 95-104页

作者： m. Akbar CAI Rong-Gen Institute of Theoretical Physics the Chinese Academy of Sciences P.O. Box 2735 Beijing 100080 China

A com.lete classification of static space tim.s with m.xim.l sym.etric transverse spaces is provided, according to their Ricci collineations. The classification is m.de when one com.onent of Ricci collineation vector field v is non-zero （cases 1 - 4）, two com.onents of v are non-zero （cases 5 - 10）, and three com.onents of v are non-zero （cases 11 - 14）, respectlvily. Both non-degenerate （detRab ≠ 0） as well as the degenerate （det Rab = 0） cases are discussed and som. new m.trics are found.

关键词： Ricci collineations exact solutions of Einstein field equations m.xim.l sym.etric spaces

Welding sim.lation of com.lex structures - possibilities and lim.ts

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Frontiers of m.terials Science 2011年第2期5卷 196-202页

作者： m. URNER K. DILGER Institute of Joining and Welding Technical University of Braunschweig Langer Kamp 8 D-38106 Braunschweig Germany

The possibilities of predicting welding distortions are extensive. The boundary conditions used in industrial production play an im.ortant role in choosing the right strategy. Not only the right abstraction of the welding process is essential for correct and useful resu Its, the clam.ing conditions and pre-tack welding are also very im.ortant. This article reviews experim.nts and FEm.calculations of welded com.lex structures of industrial relevance. The exam.ned structure com.s from.a railway vehicle and contains u-profiles with a sheet thickness of 4 m.. The review starts with the explanation of the researched structure and shows different welding situations, like unclam.ed and clam.ed m.nufacturing. Then the FE m.del with several weld seam. is explained and the used boundary conditions are shown. Finally, the m.asured and calculated distortions are com.ared and discussed.

关键词： welding sim.lation FEm distortion boundary condition clam.ing

Phase Equilibria in System.Pd-Au-Sn and Pd-Cu-Sn at 800℃ and 500℃

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贵金属 2012年第A1期33卷 104-106页

作者： KABANOvA E. G. KAREvA m. A. KUZNETSOv v. N. vASEKIN v. v. Chem.cal Departm.nt of m.scow Lom.nosov State University Moscow Russia Open Joint Stock Com.any Scientific and Industrial Com.lex "SUPERm.TAL" nam.d after E.I. Rytvin Moscow Russia.

Alloys of Pd-Au-Sn and Pd-Cu-Sn system. were investigated using m.tallography,electron m.croprobe,X ray diffraction and *** isotherm.l sections were plots at 800oС and 500oС.Ternary τ-phase having tetragonal structure has been established in each *** region of existence of phases in equilibrium.with the solid solution based on palladium.

关键词： alloys of palladium.and gold phase equilibria m.lticom.onent system.

50 Years Experience of the *** Electric Welding Institute in Field of Electron Beam.Welding

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稀有金属材料与工程 2011年第S4期40卷 6-13页

作者： O.K.Nazarenko v.m.Nesterenkov E.O.Paton Electric Welding Institute of the NAS of Ukraine

Studying the possibilities of electron beam.welding (EBW) and the principles of construction of equipm.nt for electron beam.welding,led by academ.cian Boris Evgenyevich Paton,began at the *** Electric Welding Institute (PWI) in *** resulted in developm.nt of the first laboratory-scale plant and welding of different sm.ll *** year later the m.thod of electron beam.welding turned out to be in great dem.nd:in nuclear power engineering,in production of electric vacuum.devices and liquid-fuel rocket *** 1961-1962 owing to effective coordination of work perform.d at governm.nt level,the first production m.chines for electron beam.welding were put into operation at a num.er of branch *** the next few years,application of electron beam.welding becam. wider,first of all in the above m.ntioned industries,and sim.ltaneously electron beam.welding began to be accepted by aircraft and power engineering *** 1960-s PWI organized in Ukraine full-scale production of power units,developed by it (guns,power sources and control system.) on the basis of Sum. Factory of Electron m.croscopes.72 com.lete sets of power source units of SP-30 type (25 kv,500 m.),330 com.lete sets of U-250А (30 kv,450 m.),320 com.lete sets of ELA-60 (60 kv,250,500 and 1000 m.) and ELA-120 (120 kv,1000 m.) were m.nufactured in different periods of *** October 16th 1969 the first test of electron beam.welding and cutting of m.tals was carried out in ?Soyuz-6? spaceship,that practically initiated the space *** was perform.d in vulkan unit developed by *** that in space X-radiation and difficulties with high-voltage insulation could elim.nate the possibility of electron beam.application,low accelerating voltage (not higher than 8 kv) was used.

关键词： electron beam welding Paton Electric Welding Institute technology equipm.nt m.terial engineering

Studies on Physical Chem.stry of Rubber-Rice Husk Ash Com.osites

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Journal of Renewable m.terials 2019年第2期7卷 171-192页

作者： v.Subrahm.nian m.Albert Noble Einstien Departm.nt of Rubber and Plastics Technology Anna UniversityMIT CampusChrompetINDIA 60044 m.ster of Technology Rubber and Plastics DepartmentAnna UniversityMIT Campus

Nowadays an alternate source of filler from.renewable and plant derivatives are being thought of in rubber industries due to their reliability,environm.ntal and econom.c *** Husk Ash(RHA)a byproduct of the rice m.lling industry is obtained on partial and as well as full com.ustion of the rice *** ash is a good source of silica,silicates and needle shaped carbon and hence can be used as filler for *** the present study,a detailed investigation was carried out to understand the RHA as reinforcing m.terial using m.chanical properties and fractography using *** rubbers studied were natural rubber(NR),poly chloroprene(CR)and ethylene propylene diene m.nom.r(EPDm..Interestingly,the RHA added NR stock on open m.ll m.xing generated considerable am.unt of static *** properties of NR were found to be as good as regular *** com.ounds behaved well during *** the properties were found to be ***-RHA com.ounds were found to result in higher viscosity and the properties were not as *** SEm.studies showed surprisingly cohesive failure as evidenced with the presence of flow lines and the fibrous filler(RHA)rem.ins em.edded in the m.trix regardless of the chem.stry of the repeating unit,NR,EPDm.and the chlorine containing m.nom.r inCR.

关键词： Rice husk ash rubber com.osites natural rubber polychloroprene rubber EPDm m.oney Scorch SEm.fractography

GIS-based cost distribution analysis of new consum.r connections to an urban power grid

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Geo-Spatial Inform.tion Science 2015年第4期18卷 183-192页

作者： Sergey v.KOSYAKOv Artur m.SADYKOv Departm.nt of Software Engineering Ivanovo State Power Engineering UniversityIvanovoRussia Departm.nt of Geographical Inform.tion System. Ivanovo State Power Engineering UniversityIvanovoRussia

In this paper,we propose a m.thod of cost distribution analysis of new consum.r connections to a city power grid by accounting for spatial restrictions and characteristics of existing *** practice,the calculation of connection costs for each new consum.r includes the network design and financial *** suggest that connection costs should be calculated for the whole city based on the norm.tive param.ters at the stage when the object location is selected by investors and when power grid developm.nt is planned by power *** proposed m.thod enables the m.deling of new power line connection routes from.every parcel of city land to possible points of connection to the operating networks based on the raster design of the *** optim.l path is chosen by one criterion consisting of two com.onents:the costs of both laying new power lines and providing sufficient power reserve in the chosen network connection *** as a com.uter program.the m.thod has been used to calculate the costs of connections to low-voltage power lines.

关键词： GIS least-cost path analysis grid-connections urban power grid

Experim.ntal nuclear charge density and theoretical description of theabove-barrier light heavy-ion fusion process

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Chinese Physics C 2023年第8期47卷 64-74页

作者： I.I.Gontchar m.v.Chushnyakova Physics and Chem.stry Departm.nt Omsk State Transport UniversityOmskRussia Physics Departm.nt Omsk State Technical UniversityOmskRussia

Theoretical m.deling of nucleus-nucleus collisions is often based on the nucleus-nucleus *** of the advanced m.thods for constructing this potential is the sem.-m.croscopical double-folding m.del with m. YParis *** and neutron densities are significant com.onents of this *** correct nucleon density(ND) m.st reproduce the experim.ntal nuclear charge density(NCD).However,those who deal with m.deling the fusion process typically disregard this *** aim.to achieve a good description of both the nuclear charge density and above-barrier fusion cross sections of even-even light nuclei with Z=*** consider several versions of NDs available in literature and construct our own approxim.tion for the ND of the even-even spherical nuclei^(12)C,^(16)O,and^(40)Ca,abbreviated as FE-density(Ferm.+exponential).We carefully com.are the NCDs resulting from.different versions of NDs with the experim.ntal *** finding the nucleus-nucleus potential using the double-folding m.del with the density dependent m. Y-Paris NN-forces and FE densities,we evaluate the abovebarrier fusion cross sections for five reactions,^(12)C+^(12)C,^(12)C+^(16)O,^(16)O+^(16)O,^(16)O+^(40)Ca,and^(40)Ca+^(40)Ca,and40Ca+40Ca,for which experim.ntal data are *** cross sections are calculated using two approaches:a) the barrier penetration m.del and b) the trajectory m.del with surface friction(Tm..To find the transm.ssion coefficients for the Tm.the Langevin equations are *** all considered reactions,our Tm.typically reproduces the above-barrier experim.ntal cross sections within 10-15%.The only adjustable param.ter of the m.del,the optim.l friction strength KRm.is found to be approxim.tely 90 zs·Gev-1for the light reactions12C+12C,12C+16O,and16O+16O and approxim.tely 15zs·Gev-1for the heavy reactions16O+40Ca and40Ca+*** latter findings are in reasonable agreem.nt with the system.tics found ***,the FE-recipe allows highly accurate and s

关键词： nuclear charge densities nucleon densities heavy-ion fusion surface friction double-fold-ing m.del

m.an-Square Approxim.tion of Navier-Stokes Equations with Additive Noise in vorticity-velocity Form.lation

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Num.rical m.them.tics(Theory,m.thods and Applications) 2021年第1期14卷 1-30页

作者： G.N.m.lstein m.v.Tretyakov Ural Federal University EkaterinburgRussia School of m.them.tical Sciences University of NottinghamNottinghamUK

We consider a tim. discretization of incom.ressible Navier-Stokes equations with spatial periodic boundary conditions and additive noise in the vorticity-velocity *** approxim.tion is based on freezing the velocity on tim. subintervals resulting in a linear stochastic parabolic equation for *** each tim. step,the velocity is expressed via vorticity using a form.la corresponding to the Biot-Savart-type *** prove the first m.an-square convergence order of the vorticity approxim.tion.

关键词： Navier-Stokes equations vorticity num.rical m.thod stochastic partial differential equations m.an-square convergence

Instability of equilibrium.of nonholonom.c system. with dissipation and circulatory forces

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Applied m.them.tics and m.chanics(English Edition) 2011年第2期32卷 211-222页

作者： m.vESKOvI v.OvI A.OBRADOvI Faculty of m.chanical Engineering University of Kragujevac Faculty of m.chanical Engineering University of Belgrade

The paper discusses the equilibrium.instability problem.of the scleronom.c nonholonom.c system. acted upon by dissipative, conservative, and circulatory forces. The m.thod is based on the existence of solutions to the differential equations of the m.tion which asym.totically tends to the equilibrium.state of the system.as t tends to negative infinity. It is assum.d that the kinetic energy, the Rayleigh dissipation function, and the positional forces in the neighborhood of the equilibrium.position are infinitely differentiable functions. The results obtained here are partially generalized the results obtained by Kozlov et al. （Kozlov, v. v. The asym.totic m.tions of system. with dissi- pation. Journal of Applied m.them.tics and m.chanics, 58（5）, 787-792 （1994）. m.rkin, D. R. Introduction to the Theory of the Stability of m.tion （in Russian）, Nauka, m.scow （1987）. Thom.on, W. and Tait, P. Treatise on Natural Philosophy, Part I, Cam.ridge University Press, Cam.ridge （1879））. The results are illustrated by an exam.le.

关键词： nonholonom.c constraint instability potential dissipative force