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Acoustics of a viscoelastic 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 derived that takes into account the radial vibrations of a gas bubble coated with a viscoelastic shell and located in an elastic *** small oscillations of inclusion,the problem of heat exchange between a gas,a liquid phase,a viscoelastic 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 wave equation for the bubbly *** analytical expression of the equilibrium speed of sound is written out and its dependence on the size of the viscoelastic 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 velocity 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 viscosity of butyl rubber on the frequency of disturbances at different temperature on the dispersion curves is shown.A comparison of the theory with experimental data is given.

关键词： Acoustic wave gas bubbles viscoelastic medium and shell shear modulus dispersion equation

Numerical investigation of full scale coaxial main rotor aerodynamics in hover and vertical descent

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

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

The original free vortex wake model was used for numerical *** of the aerodynamic characteristics in hover and vertical descent modes in the range of vertical descent speed of 0–30 m/s including the vortex Ring State(vRS)area was *** calculations were carried out under the condition of variable blade pitch angle values providing a fixed timeaverage thrust *** data of free vortex wake shapes,flow structures,and velocity 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 vRS area by various criteria such as rotor thrust and torque pulsations,growth of rotor power consumption relative to the hover,growth of rotor induced velocities relative to the hover,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 available results of experimental and computational studies in this area.

关键词： Aerodynamic characteristics Coaxial rotor Free wake model Hover and vertical descent vortex 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： Evgeny S.Sedov yuri G.Rubo Alexey v.Kavokin Westlake University 18 Shilongshan RoadHangzhou 310024 Zhejiang ProvinceChina Institute of Natural Sciences Westlake Institute for Advanced Study18 Shilongshan RoadHangzhou 310024 Zhejiang ProvinceChina vladimir State University Gorky str.87Vladimir 600000Russia Instituto de Energias Renovables Universidad Nacional Autonoma de Mexico62580 TemixcoMORMexico Spin Optics Laboratory Saint Petersburg State University1 UlianovskayaSt.Petersburg 198504Russia

We propose a novel photonic device,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 wave packet and the dynamics of the polariton pseudospin governed by the spatially dependent effective 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 *** gives 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.Kazantseva 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 values 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 variations 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 average strength and the isotopic composition of precipitation for a series of observations at Kungur Station;for a series of observations 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 elevated temperatures by increasing their *** the breakdown of the stable stratification of Lake Shira(2015-2016),zooplankton abundance increased on average 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 previous ***,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

Neurohumoral,cardiac and inflammatory markers in the evaluation of heart failure severity and progression

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Journal of Geriatric Cardiology 2021年第1期18卷 47-66页

作者： Ekaterina A Polyakova Evgeny N Mikhaylov Dmitry L Sonin yuri v Cheburkin Mikhail M Galagudza Almazov National Medical Research Centre Saint-PetersburgRussia

Heart failure is common in adult population,accounting for substantial morbidity and mortality *** main risk factors for heart failure are coronary artery disease,hypertension,obesity,diabetes mellitus,chronic pulmonary diseases,family history of cardiovascular diseases,cardiotoxic *** main factor associated with poor outcome of these patients is constant progression of heart *** the current review we present evidence on the role of established and candidate neurohumoral biomarkers for heart failure progression management and diagnostics.A growing number of biomarkers have been proposed as potentially useful in heart failure patients,but not one of them still resembles the characteristics of the"ideal biomarker."A single marker will hardly perform well for screening,diagnostic,prognostic,and therapeutic management ***,the pathophysiological and clinical significance of biomarkers may depend on the presentation,stage,and severity of the *** authors cover main classification of heart failure phenotypes,based on the measurement of left ventricular ejection fraction,including heart failure with preserved ejection fraction,heart failure with reduced ejection fraction,and the recently proposed category heart failure with mid-range ejection *** could envisage specific sets of biomarker with different performances in heart failure progression with different left ventricular ejection fraction especially as concerns prediction of the future course of the disease and of left ventricular adverse/reverse *** article is intended to provide an overview of basic and additional mechanisms of heart failure progression will contribute to a more comprehensive knowledge of the disease pathogenesis.

关键词： cardiac and inflammatory markers in the evaluation of heart failure severity and progression Neurohumoral

Neurogenic potential of NG2 in neurotrauma:a systematic review

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Neural Regeneration Research 2024年第12期19卷 2673-2683页

作者： yuri R.Rigo Radharani Benvenutti Luis v.Portela Nathan R.Strogulski Departamento de Bioquímica Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do Sul(UFRGS)Porto AlegreBrazil School of Pharmacy and Biomolecular Sciences RCSI University of Medicine and Health SciencesDublinIreland School of Biochemistry and Immunology Trinity Biomedical Sciences InstituteTrinity College DublinUniversity of DublinDublinIreland

Regenerative approaches towards neuronal loss following traumatic brain or spinal cord injury have long been considered a dogma in neuroscience and remain a cutting-edge area of *** is reflected in a large disparity between the number of studies investigating primary and secondary injury as therapeutic to rgets in spinal co rd and traumatic brain *** advances in biotechnology may have the potential to reshape the current state-of-the-art and bring focus to primary injury neurotrauma *** studies using neural-glial factor/antigen 2(NG2)cells indicate that they may differentiate into neurons even in the developed *** these cells show great potential to play a regenerative role,studies have been conducted to test various manipulations in neurotrauma models aimed at eliciting a neurogenic response from *** the present study,we systematically reviewed the experimental protocols and findings described in the scientific literature,which were peer-reviewed original research articles(1)describing preclinical experimental studies,(2)investigating NG2 cells,(3)associated with neurogenesis and neurotrauma,and(4)in vitro and/or in vivo,available in PubMed/MEDLINE,Web of Science or SCOPUS,from 1998 to ***,we have reviewed a total of 1504 papers,and summarized findings that ultimately suggest that NG2 cells possess an inducible neurogenic potential in animal models and in *** also discriminate findings of NG2 neurogenesis promoted by different pharmacological and genetic approaches over functional and biochemical outcomes of traumatic brain injury and spinal co rd injury models,and provide mounting evidence for the potential benefits of manipulated NG2 cell ex vivo transplantation in primary injury *** findings indicate the feasibility of NG2 cell neurogenesis strategies and add new players in the development of therapeutic alternatives for neurotrauma.

关键词： neural-glial antigen 2 neural-glial factor 2 neuron differentiation NG2 cell regeneration spinal cord injury(SCI) traumatic brain injury(TBI)

Mortarless structures based on topological interlocking

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Frontiers of Structural and Civil Engineering 2012年第2期6卷 188-197页

作者： Arcady v.DYSKIN Elena PASTERNAK yuri ESTRIN School of Civil and Resource Engineering The University of Western AustraliaCrawley WA 6009Australia School of Mechanical and Chemical Engineering The University of Western AustraliaCrawley WA 6009Australia Centre for Advanced Hybrid Materials Department of Materials EngineeringMonash UniversityClayton VIC 3800Australia

We review the principle of topological interlocking and analyze the properties of the mortarless structures whose design is based on this *** concentrate on structures built of osteomorphic blocks-the blocks possessing specially engineered contact surfaces allowing assembling various 2D and 3D *** structures are easy to build and can be made *** are flexible,resistant to macroscopic fractures and tolerant to missing *** blocks are kept in place without keys or connectors that are the weakest elements of the conventional interlocking *** overall structural integrity of these structures depends on the force imposed by peripheral *** peripheral constraint can be provided in various ways:by an external flame or features of site topography,intemal prestressed cables/tendons,or self-weight and is a necessary auxiliary element of the *** constraining force also determines the degree of delamination developing between the blocks due to bending and thus controls the overall flexibility of the structure thus becoming a new design parameter.

关键词： topological interlocking fragmented structures segmented structures constraint delamination bending stiffness

A NUMERICAL METHOD FOR THE SIMULATION OF FREE SURFACE FLOWS OF vISCOPLASTIC 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. vassilevski 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 viscoplastic （Herschel-Bulkley） fluids. The approach is based on the level set method for capturing the free surface evolution and on locally refined and dynamically adapted octree cartesian staggered grids for the discretization of fluid and level set equations. A regu- larized model is applied to handle the non-differentiability of the constitutive relations. We consider an extension of the stable approximation of the Newtonian flow equations on staggered grid to approximate the viscoplastic model and level-set equations if the free boundary evolves and the mesh is dynamically refined or coarsened. The numerical method is first validated for a Newtonian case. In this case, the convergence of numerical solutions is observed towards experimental data when the mesh is refined. Further we compute several 3D viscoplastic Herschel-Bulkley fluid flows over incline planes for the dam-break problem. The qualitative comparison of numerical solutions is done versus experimental investigations. Another numerical example is given by computing the freely oscillating viscoplastic droplet, where the motion of fluid is driven by the surface tension forces. Altogether the considered techniques and algorithms （the level-set method, compact discretizations on dynamically adapted octree cartesian grids, regularization, and the surface tension forces approximation） result in efficient approach to modeling viscoplastic free-surface flows in possibly complex 3D geometries.

关键词： Free surface flows viscoplastic fluid Adaptive mesh refinement Oetree meshes.