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Three-Dimensional Convection in an Inclined Porous Layer Subjected to a vertical Temperature Gradient

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Fluid Dynamics & Materials Processing 2024年第9期20卷 1957-1970页

作者： Ivan Shubenkov Tatyana Lyubimova evgeny Sadilov Computational Fluid Dynamics Laboratory Institute of Continuous Media Mechanics UB RASPerm614068Russia Theoretical Physics Department Perm State UniversityPerm614990Russia

In this paper,we study the onset and development of three-dimensional convection in a tilted porous layer saturated with a *** layer is subjected to a gravitational field and a strictly vertical temperature ***,problems of thermal convection in tilted porous media saturated with a liquid are studied by assuming constant different temperatures at the boundaries of the layer,which prevent these systems from supporting conductive(non-convective)*** boundary conditions considered in the present work allow a conductive state and are representative of typical geological *** an earlier work,we carried out a linear stability analysis of the conductive *** was shown that at any layer tilt angles,the most dangerous type of disturbances are longitudinal ***,a non-zero velocity component exists in *** the present work,threedimensional non-linear convection regimes are *** original three-dimensional problem is reduced to two-dimensional one with an analytical expression for the velocity z-component v_(z)=v_(z)(x,y).It is shown that the critical Rayleigh number values obtained through numerical solutions of the obtained 2D problem by a finite difference method for different layer inclination angles,are in a good agreement with those predicted by the linear *** number of convective rolls realized in nonlinear calculations also fits the linear theory predictions for a given cavity *** carried out at low supercriticalities show that a direct bifurcation takes *** increasing supercriticality,no transitions to other convective regimes are *** situation studied in this problem can be observed in oil-bearing rock formations under the influence of a geothermal temperature gradient,where the ensuing fluid convection can affect the distribution of oil throughout the layer.

关键词： Thermal convection inclined layer porous media vertical temperature gradient

Elucidating elusive quaternary selenide EuCeCuSe3:Synthesis,crystal structure,properties and theoretical studies

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Journal of Rare Earths 2024年第1期42卷 163-171,I0006页

作者： Maxim v.Grigoriev Anna v.Ruseikina Maxim S.Molokeev vladimir A.Chernyshev Aleksandr S.Aleksandrovsky Alexander S.Krylov Svetlana N.Krylova Nikolai P.Shestakov Dmitriy A.velikanov Alexander A.Garmonov Alexey v.Matigorov evgeny A.Ostapchuk Thomas Schleid Damir A.Safin Laboratory of Theory and Optimization of Chemical and Technological Processes University of TyumenVolodarskogo Str.6625003TyumenRussian Federation Kirensky Institute of Physics Federal Research Center KSC SB RASAkademgorodok 50 Bld.38660036KrasnoyarskRussian Federation Department of Physics Far Eastern State Transport UniversitySerysheva Str.47680021KrasnoyarskRussian Federation Institute of Natural Sciences and Mathematics Ural Federal University Named After the First President of Russia B.N.YeltsinMira Str.19620002EkaterinburgRussian Federation Department of Photonics and Laser Technology Siberian Federal UniversitySvobodnii Ave.79660079KrasnoyarskRussian Federation Institute of Physics and Technology University of TyumenVolodarskogo Str.6625003 TyumenRussian Federation Institute for Inorganic Chemistry University of StuttgartPfaffenwaldring 55D-70569StuttgartGermany Scientific and Educational and Innovation Center for Chemical and Pharmaceutical Technologies Ural Federal University named after the First President of Russia B.N.YeltsinMira Str.19620002 EkaterinburgRussian Federation University of Tyumen Volodarskogo Str.6625003TyumenRussian Federation

We report on the novel heterometallic quaternary selenide EuCeCuSe3,the fabrication of which has been a challenge until this *** structure of the reported selenide was elucidated from the powder X-ray diffraction data,which revealed the formation of EuCeCuSe3with excellent yield(96.7%)accompanied with a minor fraction of CeSe2(3.3%),and was best solved in orthorhombic space group Pnma with the BaLaCuS3structural ***,the crystal structure of the title compound completes the row of the heterometallic quaternary selenides EuRECuSe3(RE=La,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y),of which the cerium-based derivative exclusively belongs to the BaLaCuS3structural *** distortion of the CuSe4polyhedron was compared for the whole series of EuRECuSe3compounds using theτ4-descriptor for four coordinated ions,which revealed the highest degree of distortion for the Ce3+-containing selenide,followed by the La3+-based ***,the crystallographic and geometrical parameters of the reported selenide were discussed in comparison to the Ce3+-based sulfides SrCeCuS3and *** initio calculations of the crystal structure,a phonon spectrum and elastic constants for the crystal of EuCeCuSe3were also *** types and wavenumbers of fundame ntal modes were determined and the involvement of ions participating in the phonon modes was *** experimental IR spectrum of the reported selenide was interpreted and found to be in agreement with the calculated *** experimental direct band gap of EuCeCuSe3was measured to be 1.36 ev that is consistent with the concept of its origin due to interband transitions between orbitals emerging mainly from 4f(valence band)and 5d(conduction band)levels of the Eu2+*** dependence of the Young’s modulus on the direction demonstrates the anisotropy of the elastic properties,while the vickers hardness for EuCeCuSe3was calculated to be 5.2 ***,the title compound is paramagnetic above 4 K.

关键词： Quaternary selenide Synthesis Crystal structure Ab initio calculations Magnetic measurements Spectroscopy

Cumulation of a spherically converging shock wave in metals and its dependence on elastic-plastic properties, phase transitions, spall and shear fractures

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International Journal of Modeling, Simulation, and Scientific Computing 2015年第1期6卷 26-38页

作者： evgeny A.Kozlov Alexsander v.Petrovtsev Russian Federal Nuclear Center-Zababakhin Research Institute of Technical Physics Snezhinsk Chelyabinsk RegionRussia

Consideration is given to results of experimental and theoretical investigations how alpha-epsilon phase transition in the unalloyed iron and the 30 KhGSA steel and its absence in the austenitic 12Kh18N10T stainless steel influence processes under explosive deformation of spheres made of these *** transition is shown to significantly effect on:amount of explosion-products energy transferred to a sphere,evolution of the converging-wave structure and its parameters,profiles of stress wave and temperature T(R,t)for some Lagrangian particles along the sphere radius,character of energy cumulation under spherical convergence of waves.

关键词： Cumulation spherically converging shock wave elastic-plastic properties phase transitions spall and shear fractures

Numerical 3D-modeling of spall and shear fractures in shells of austenitic 12Kh18N10T steel and 30KhGSA steel under their spherical and quasi-spherical explosive loading

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International Journal of Modeling, Simulation, and Scientific Computing 2015年第1期6卷 173-211页

作者： evgeny A.Kozlov Oleg v.Ol’khov Ekaterina v.Shuvalova Russian Federal Nuclear Center–Zababakhin Research Institute of Technical Physics Snezhinsk Russia Russian Federal Nuclear Center–Research Institute of Experimental Physics Sarov Russia

To pursue vNIIEF–vNIITF joint investigations,this paper briefly describes the experimental setup and provides numerical 3D-computation results(LEGAK-3D technique)on special features in the convergence dynamics of steel shells under their quasi-spherical explosive loading in the system with the 40-mm outer radius of the explosive *** computation results were compared with the data experimentally registered for shells of the 30KhGSA steel,both as-received and quenched to HRC 35...40,and the austenitic 12Kh18N10T stainless *** comparison was also made with laserinterferometry results obtained directly under explosive loading,as well as with gammatomography and scanning electron microscopy investigations of the recovered shells.

关键词： Convergence dynamics of shell spall and shear damages explosive loading

Trace amine-associated receptors at the cross-road between innate olfaction of amines, emotions, and adult neurogenesis

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Neural Regeneration Research 2022年第6期17卷 1257-1258页

作者： Evgeniya v.Efimova Nataliia v.Katolikova evgeny v.Kanov Raul R.Gainetdinov Institute of Translational Biomedicine and Saint Petersburg University Hospital Saint Petersburg State UniversitySaint PetersburgRussia

Trace amines are the class of endogenous biogenic amines that traditionally include beta-phenylethylamine,p-tyramine,tryptamine,octopamine,and o *** t race amines represent products of amino acids decarboxylation by bacterial decarboxylases during tissue putrefaction or by endogenous decarboxylases in the *** of trace amines by gut microbiota is also known(Berry et al.,2017;Gainetdinov et al.,2018).Thus,trace amines are enriched during the decomposition of proteins and concentrated in certain bodily fluids.

关键词： amines Berry concentrated

Compliance and adherence to oral anticoagulation therapy in elderly patients with atrial fibrillation in the era of direct oral anticoagulants

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Journal of Geriatric Cardiology 2016年第9期13卷 807-810页

作者： Svetlana v Garkina Tatiana v vavilova Dmitry S Lebedev evgeny N Mikhaylov Arrhythmia Department Almazov Federal North-West Medical Research Centre Saint-Petersburg Russian Federation Nearomodulation unit Almazov Federal North-West Medical Research Centre Saint-Petersburg Russian Federation Department of Clinical Laboratory Diagnostics and Genetics Almazov Federal North-West Medical Research Centre Saint-Petersburg Russian Federation

Thromboembolic complications represent a substantial problem in patients with atrial fibrillation （AF）. The prevalence of AF burden and associated arterial and venous thrombosis progressively increases with age. At ... 详细信息

关键词： Adherence Anticoagulation Atrial fibrillation Compliance Direct anticoagulants Elderly Novel oral anticoagulants

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

Acoustic emission characterization of sliding wear under condition of direct and inverse transformations in lowtemperature degradation aged Y-TZP and Y-TZP-Al_2O_3

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Friction 2018年第3期6卷 323-340页

作者： Nikolai L SAvCHENKO Andrey v FILIPPOv Sergei Yu TARASOv Andrey I DMITRIEv evgeny v SHILKO Aleksandr S GRIGORIEv Institute of Strength Physics and Materials Science SB RAS National Research Tomsk Polytechnic University National Research Tomsk State University

In this research, results of the investigation of the sliding friction and wear of yttria-stabilized tetragonal zirconia polycrystalline(Y-TZP) and Y-TZP-Al_2O_3 samples preliminarily subjected to low-temperature degradation are reported. The investigation was carried out using a pin-on-disk tribometer with simultaneous recording of acoustic emission(AE) and vibration acceleration. The sliding wear process was found to be determined by dynamic direct and inverse Y-TZP transformations detected by monoclinic and tetragonal X-ray diffraction peak ratios. The AE signals generated under direct and inverse transformations can be used to characterize wear and friction mechanisms as well as direct and inversed sliding-induced phase transformations. The AE signal energy grows with the friction coefficient and the inverse transformation degree. Reduction of the AE signal energy indicates establishing the mild wear stage caused by effective stress-induced direct martensitic transformation. The AE signal median frequency increases in the case of lower friction. Numerical studies of wear subsurface fracture under conditions of stress-induced martensitic transformation were used to elucidate the role played by the phase transformation in Y-TZP and Y-TZP-Al_2O_3. Martensitic transformation in Y-TZP was described with use of the non-associated dilatant plasticity model. Simulation results particularly show that increase in the value of dilatancy coefficient from 0 to 0.2 is accompanied by 25%-30% reduce in characteristic length and penetration depth of sliding-induced subsurface cracks. As shown the AE may be an effective tool for in-situ monitoring the subsurface wear of materials experiencing both direct and inverse transformations.

关键词： zirconia transformation toughening low-temperature degradation friction acoustic emission numerical modeling movable cellular automata method

Asymmetry ratio as a parameter of Eu^3＋ local environment in phosphors

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Journal of Rare Earths 2018年第5期36卷 474-481页

作者： Ilya E. Kolesnikov Alexey v. Povolotskiy Daria v. Mamonova evgeny Yu. Kolesnikov Alexey v. Kurochkin Erkki Lahderanta Mikhail D. Mikhailov Saint Petersburg State University 7/9 Universitetskaya nab. 199034 St.petersburg.Russia Lappeenranta University of Technology LUT Skinnarilankatu 34 53850 Lappeenranta Finland Scientific and Technological Institute of Optical Material Science VNTs S. I. Vavilov State Optical Institute Babushkina 36-1 192171 St. Petersburg Russia volga State University of Technology Lenin Sq. 3 424000 Yoshkar-Ola Russia

Study of the local environment of certain ion is quite a complex problem. Due to the unique luminescent properties, Eu^3＋ ions can be used as a structural probe. In this paper, effect of doping concentration,excitation wavelength and excitation mechanism on asymmetry ratio was systematically studied using Y3Al5O12：Eu^3＋, YvO4：Eu^3＋ and Y2O3：Eu^3＋nanophosphors. The asymmetry ratio gives information about the local surrounding and environmental changes around the Eu^3＋ ions. Asymmetry ratios of YAG：Eu^3＋and YvO4：Eu^3＋ nanopowders were calculated using standard technique and the obtained average values were found to be 0.75 and 8.2, respectively. However, it is found that standard method of asymmetry ratio calculation is suitable only for samples where all Eu^3＋ ions occupy one site. The ＂multisite model＂ of asymmetry ratio calculation was developed and used for Y2O3：Eu^3＋ nanocrystalline powders. Average value of asymmetry ratio for Eu^3＋ ions occupied ＂normal＂ sites is 6.0 and for Eu^3＋ ions occupied ＂defect＂sites is 2.3.

关键词： Eu3+ Oxide powders Luminescence Asymmetry ratio Structural probe Rare earths