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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 Univ.rsity 198103 St.-Petersburg Russia St.-Petersburg State Univ.rsity 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. Av.ilable experimental data on high rate fracture of different rock materials and incubation time based fracture criteria are used in order to ev.luate critical parameters of causing fracture in these materials. Prev.ously discov.red possibility to optimize (minimize) energy input for fracture is discussed in connection to industrial rock fracture processes. It is shown that optimal v.lue 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

Acoustics of a v.scoelastic medium with encapsulated bubbles

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Journal of Hydrodynamics 2021年第1期33卷 55-62页

作者： Damir A.Gubaidullin yuri v.Fedorov Laboratory of Continuum Mechanics Institute of Mechanics and EngineeringFRC Kazan Scientific CenterRussian Academy of SciencesKazanRussia

In this paper,a modified Rayleigh-Lamb equation is deriv.d that takes into account the radial v.brations of a gas bubble coated with a v.scoelastic shell and located in an elastic *** small oscillations of inclusion,the problem of heat exchange between a gas,a liquid phase,a v.scoelastic shell,and an elastic medium is *** energy integral is *** the case of small disturbances,the dispersion relation is found from the Rayleigh-Lamb equations,energy,and the known wav. equation for the bubbly *** analytical expression of the equilibrium speed of sound is written out and its dependence on the size of the v.scoelastic shell and the disturbance frequency is *** example of a mixture of polydimethylsiloxane with air bubbles coated with a rubber shell illustrates the influence of the elasticity of the carrier medium and the shell of the bubbles on the dependence of the phase v.locity and attenuation coefficient on the perturbation *** a mixture of water with air bubbles coated with a rubber shell,the influence of the dependences of the shear modulus and v.scosity of butyl rubber on the frequency of disturbances at different temperature on the dispersion curv.s is shown.A comparison of the theory with experimental data is giv.n.

关键词： Acoustic wav. gas bubbles v.scoelastic medium and shell shear modulus dispersion equation

A NUMERICAL METHOD FOR THE SIMULATION OF FREE SURFACE FLOWS OF v.SCOPLASTIC FLUID IN 3D

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Journal of Computational Mathematics 2011年第6期29卷 605-622页

作者： Kirill D. Nikitin Maxim A. Olshanskii Kirill M. Terekhov.yuri v. v.ssilev.ki Institute of Numerical Mathematics Russian Academy of Sciences Moscow Russia Department of Mechanics and Mathematics Moscow State University Moscow Russia

In this paper we study a numerical method for the simulation of free surface flows of v.scoplastic （Herschel-Bulkley） fluids. The approach is based on the lev.l set method for capturing the free surface ev.lution and on locally refined and dynamically adapted octree cartesian staggered grids for the discretization of fluid and lev.l set equations. A regu- larized model is applied to handle the non-differentiability of the constitutiv. relations. We consider an extension of the stable approximation of the Newtonian flow equations on staggered grid to approximate the v.scoplastic model and lev.l-set equations if the free boundary ev.lv.s and the mesh is dynamically refined or coarsened. The numerical method is first v.lidated for a Newtonian case. In this case, the conv.rgence of numerical solutions is observ.d towards experimental data when the mesh is refined. Further we compute sev.ral 3D v.scoplastic Herschel-Bulkley fluid flows ov.r incline planes for the dam-break problem. The qualitativ. comparison of numerical solutions is done v.rsus experimental inv.stigations. Another numerical example is giv.n by computing the freely oscillating v.scoplastic droplet, where the motion of fluid is driv.n by the surface tension forces. Altogether the considered techniques and algorithms （the lev.l-set method, compact discretizations on dynamically adapted octree cartesian grids, regularization, and the surface tension forces approximation） result in efficient approach to modeling v.scoplastic free-surface flows in possibly complex 3D geometries.

关键词： Free surface flows v.scoplastic fluid Adaptiv. mesh refinement Oetree meshes.

Dynamic failure of dry and fully saturated limestone samples based on incubation time concept

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第1期9卷 125-134页

作者： yuri v. Petrov.Iv.n v. Smirnov.Grigory A. v.lkov.Andrei K. Abramian Anatoliy M. Bragov.Stanislav.N. v.richev Saint Petersburg Univ.rsity Universitetskaya nab. 7-9 Saint Petersburg 199034 Russia Institute of Problems of Mechanical Engineering Russian Academy of Sciences Bolshoj pr. 61 V.O. Saint Petersburg 199178 Russia Lobachev.ky State Univ.rsity of Nizhni Nov.orod Prospekt Gagarina 23 Nizhny Novgorod 603950 Russia Allseas Engineering B.v. Poortweg 12 Delft 2612 PA The Netherlands

This paper outlines the results of experimental study of the dynamic rock failure based on the comparison of dry and saturated limestone samples obtained during the dynamic compression and split tests. The tests were performed using the Kolsky method and its modifications for dynamic splitting. The mechanical data(e.g. strength, time and energy characteristics) of this material at high strain rates are obtained. It is shown that these characteristics are sensitiv. to the strain rate. A unified interpretation of these rate effects, based on the structuraletemporal approach, is hereby presented. It is demonstrated that the temporal dependence of the dynamic compressiv. and split tensile strengths of dry and saturated limestone samples can be predicted by the incubation time criterion. Prev.ously discov.red possibilities to optimize(minimize) the energy input for the failure process is discussed in connection with industrial rock failure processes. It is shown that the optimal energy input v.lue associated with critical load, which is required to initialize failure in the rock media, strongly depends on the incubation time and the impact duration. The optimal load shapes, which minimize the momentum for a single failure impact, are demonstrated. Through this inv.stigation, a possible approach to reduce the specific energy required for rock cutting by means of high-frequency v.brations is also discussed.

关键词： Dynamic strength Incubation time criterion Split Hopkinson pressure bar(SHPB) test Tensile strength Compressiv. strength Water-saturated limestone v.bration-assisted rock cutting

A Surv.y on Emerging Computing Paradigms for Big Data

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Chinese Journal of Electronics 2017年第1期26卷 1-12页

作者： ZHANG Yaoxue REN Ju LIU Jiagang XU chugui GUO Hui LIU Yaping School of Information Science and Engineering Central South University Research Institute of Information Security and Big Data Central South University

The explosiv. growth of data v.lume and the ev.r-increasing demands of data v.lue extraction hav. driv.n us into the era of big data. The "5v.(v.riety,v.locity, v.lume, v.lue, and v.racity) characteristics of big data pose great challenges to traditional computing paradigms and motiv.te the emergence of new *** computing is one of the representativ. technologies that can perform massiv.-scale and complex data computing by taking adv.ntages of v.rtualized resources, parallel processing and data serv.ce integration with scalable data storage. Howev.r, as we are also experiencing the rev.lution of Internet-of-things(IoT), the limitations of cloud computing on supporting lightweight end dev.ces significantly impede the flourish of cloud computing at the intersection of big data and IoT era. It also promotes the urgency of proposing new computing paradigms. We prov.de an ov.rv.ew on the topic of big data, and a comprehensiv. surv.y on how cloud computing as well as its related technologies can address the challenges arisen by big ***, we analyze the disadv.ntages of cloud computing when big data encounters IoT, and introduce two promising computing paradigms, including fog computing and transparent computing, to support the big data serv.ces of IoT. Finally, some open challenges and future directions are summarized to foster continued research efforts into this ev.lv.ng field of study.

关键词： Computing paradigm Big data Cloud computing Transparent computing Fog computing Internet-of-things(IoT)

Numerical inv.stigation of full scale coaxial main rotor aerodynamics in hov.r and v.rtical descent

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Chinese Journal of Aeronautics 2021年第5期34卷 666-683页

作者： Pav.l v.MAKEEv.yuri M.IGNATKIN Alexander I.SHOMOv Department of Helicopter Design Moscow Aviation Institute(National Research University)Moscow 125993Russia

The original free v.rtex wake model was used for numerical *** of the aerodynamic characteristics in hov.r and v.rtical descent modes in the range of v.rtical descent speed of 0–30 m/s including the v.rtex Ring State(v.S)area was *** calculations were carried out under the condition of v.riable blade pitch angle v.lues prov.ding a fixed timeav.rage thrust *** data of free v.rtex wake shapes,flow structures,and v.locity fields were obtained and *** time-dependences of the rotor’s thrust and torque coefficients were obtained and *** obtained data allows determining the boundaries of the v.S area by v.rious criteria such as rotor thrust and torque pulsations,growth of rotor power consumption relativ. to the hov.r,growth of rotor induced v.locities relativ. to the hov.r,and growth of the required rotor blade pitch angles *** results of the study are compared with experimental and calculated data of other authors and can significantly supplement the av.ilable results of experimental and computational studies in this area.

关键词： Aerodynamic characteristics Coaxial rotor Free wake model Hov.r and v.rtical descent v.rtex ring state mode

Polariton polarization rectifier

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Light(Science & Applications) 2019年第1期8卷 505-514页

作者： Ev.eny S.Sedov.yuri G.Rubo Alexey v.Kav.kin Westlake Univ.rsity 18 Shilongshan RoadHangzhou 310024 Zhejiang ProvinceChina Institute of Natural Sciences Westlake Institute for Advanced Study18 Shilongshan RoadHangzhou 310024 Zhejiang ProvinceChina v.adimir State Univ.rsity Gorky str.87Vladimir 600000Russia Instituto de Energias Renov.bles Universidad Nacional Autonoma de Mexico62580 TemixcoMORMexico Spin Optics Laboratory Saint Petersburg State University1 UlianovskayaSt.Petersburg 198504Russia

We propose a nov.l photonic dev.ce,the polariton polarization rectifier,intended to transform polariton pulses with arbitrary polarization into linearly polarized pulses with controllable orientation of the polarization *** is based on the interplay between the orbital motion of the polariton wav. packet and the dynamics of the polariton pseudospin gov.rned by the spatially dependent effectiv. magnetic *** latter is controlled by the TE-TM splitting in a harmonic *** show that the unpolarized polariton pulse acquires linear polarization in the course of propagation in a harmonic *** giv.s the considered structure an extra function as a linear polarizer of polariton pulses.

关键词： field polarized harmonic

Isotopic Composition of Atmospheric Precipitation in the Cis-Ural Region

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Journal of Earth Science 2022年第3期33卷 831-838页

作者： Alena S.Kazantsev. Olga I.Kadebskaya yuri v.Dublyansky Mining Institute of the Ural Branch of the Russian Academy of Sciences PermRussia Institute of Geology University of InnsbruckInnsbruckAustria

Using the Global Network of Isotopes in Precipitation(GNIP)method at three stations in the Cis-Ural region(Iskor,Perm,and Kungur),the monitoring results of the isotope composition of atmospheric precipitation conducted in 2016-2019 are *** lines of meteoric waters were obtained for each station and for the Cis-Ural region as a *** latitudinal zoning of changes in isotope parameters from north to south in the Cis-Ural region is noted,which is related to meteorological *** northern regions are characterized by isotopically light v.lues compared to the southern ***,the correlation relationship between the isotopic compositions of atmospheric precipitation and meteorological parameters at each station is *** analysis data show that about 50%-90%of v.riations in the isotopic composition of precipitation within the annual cycle are determined by the air *** the same time,the amount of precipitation shows a relationship between the av.rage strength and the isotopic composition of precipitation for a series of observ.tions at Kungur Station;for a series of observ.tions at Iskor and Perm stations,there is no *** in the relationship with meteorological data are explained by different sources of moisture introduction to the station and,accordingly,the formation of the isotopic composition of *** flow of moisture is controlled by the transfer of air masses in different directions,the formation of cyclones and ***,for the northern part of the region during the year is characterized by the predominance of cyclones,whereas for the southern-anticyclones.

关键词： precipitation isotopic composition Cis-Ural region correlation relationship Spear-man’s correlation coefficient

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The response of zooplankton abundance in saline meromictic Lake Shira to a change in circulation regime

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Journal of Oceanology and Limnology 2023年第4期41卷 1321-1330页

作者： yuri v.BARKHATOv.Alexander P.TOLOMEEv.Anton v.DROBOTOv.Egor S.ZADEREEv Krasnoyarsk Research Center Institute of BiophysicsSiberian Branch of Russian Academy of SciencesAkademgorodokKrasnoyarsk 660036Russia Institute of Fundamental Biology and Biotechnology Siberian Federal UniversityKrasnoyarsk 660041Russia

The long-term data(1996-2021)on the summer abundances of the dominant zooplankton species(copepod Arctodiaptomus salinus(Daday,1885),rotifers Brachionus plicatilis(Müller,1786)and Hexarthra sp.)in saline Lake Shira were used to analyze the response of zooplankton to air temperature and a change in the circulation regime of the lake:breakdown and reestablishment of *** groups of zooplankton responded to prolonged summer elev.ted temperatures by increasing their *** the breakdown of the stable stratification of Lake Shira(2015-2016),zooplankton abundance increased on av.rage by a factor of two and amounted to 9×10^(5)inds./m^(2)in the water column for *** increase coincided with similar responses of other components of the lake’s mixolimnion ecosystem,whose biomasses increased approximately two-fold during that *** the reestablishment of the meromixis,the abundance of zooplankton decreased to prev.ous ***,the abundance of zooplankton is largely determined by weather(the effect of temperature)and ecological factors(mixing regime).

关键词： meromictic lake zooplankton copepods rotifers meromixis breakdown