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Fractionation and fixation of rare earth elements in soils:Effect of spiking with lanthanum,cerium,and neodymium chlorides

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Journal of Rare Earths 2022年第1期40卷 143-152页

作者： Olga B.Rogova petr s.fedotov Rustam Kh.Dzhenloda Vasily K.Karandashev V.V.Dokuchaev soil science Institute Russian Academy of Sciences7 Building 2 Pyzhevskiy Side StreetMoscow119017Russia V.I.Vernadsky Institute of Geochemistry and Analytical Chemistry Russian Academy of Sciences19 Kosygin StreetMoscow119991 Russia National University of science and Technology'MIsis' 4 Leninsky ProspectMoscow119049Russia The Institute of Microelectronics Technology and High-Purity Materials Russian Academy of Sciences6 Institution StreetChernogolovka142432Russia

Industrial and agricultural activities lead to the release of rare earth elements(REEs)in wastewater and aquatic ecosystems,and their accumulation in ***,the behavior of REEs in soils remains somewhat *** the present work the fractionation and fixation of REEs in soddy-podzolic and chernozem soils spiked with La,Ce,and Nd chlorides were studied using dynamic(continuous flow)extraction,which allows natural conditions to be mimicked and artefacts to be *** eluents applied are aimed to dissolve exchangeable,specifically sorbed,bound to Mn oxides,bound to metal-organic complexes,and bound to amorphous and poorly ordered Fe/Al oxides fractions extractable by 0.05 mol/L Ca(NO_(3))2,0.43 mol/L CH_(3)COOH,0.1 mol/L NH_(2)OH·HCl,0.1 mol/L K_(4)P_(2)O_(7) at pH 11,and 0.1 mol/L(NH4)_(2)C_(2)O_(4) at pH 3.2,*** is found that the fixations of added La,Ce,and Nd in the form of metal-organic complexes is predominant for both types of soils:35%-38%in soddy-podzolic soil and 50%-79%in *** fixation of added elements in the first three fractions(exchangeable,specifically sorbed,and bound to Mn oxides)is significant for soddy-podzolic soil(5%-25%).For chernozem,the relative contents of added Ce and Nd in these fractions are nearly *** the content of exchangeable La is notable,about 5%.Adding any of three elements(La,Ce,or Nd)at the level of100 mg/kg to an initial sample results in changing the fractionation and bioaccessibility of other REEs present in *** contents increase in the first three fractions and decrease in fifth(oxalate extractable)fraction for both soddy-podzolic soil and *** main difference is the behavior of REEs in pyrophosphate extractable *** soddy-podzolic soil,adding La,Ce,or Nd results in decreasing the contents of other REEs associated with organic *** chernozem,on the contrary,the contents of REEs in the form of metal-organic complexes slightly *** processes

关键词： Rare earth elements soddy-podzolic soil Chernozem Fractionation Competitive binding

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Renal artery denervation suppresses intractable ventricular arrhythmia in patients with left heart thrombosis

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Journal of Geriatric Cardiology 2017年第9期14卷 587-589页

作者： Marianna A Vander petr A fedotov Tamara A Lyubimtseva Maria A Bortsova Maria Yu simikova Dmitry s Lebedev Evgeny N Mikhaylov Neuromodulation Unit Almazov National Medical Research Centre Saint-Petersburg Russia Arrhythmia Department Almazov National Medical Research Centre Saint-Petersburg Russia Heart Failure Department Almazov National Medical Research Centre Saint-Petersburg Russia

Transcutaneous renal artery denervation （RND） has beeninitially developed for destruction of efferent nerve fireswith luminal delivery of radiofrequency or ultrasonic energyaiming blood pressure reduction in patients with refractoryhypertension. However, other positive results of RNDwere described afterwards, and they include suppression ofatrial fibrillation and ventricular tachycardia （VT） storm.

关键词： Renal nerve denervation sympathetic nerve activity Ventricular tachyarrhythmias

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Model of homogenisation for analysing the effect of micrometre pore sizes on the elastic moduli of porous materials

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Acta Mechanica sinica 2019年第5期35卷 1060-1066页

作者： A.F.fedotov Department of Mechanics Samara State Technical UniversitySamara 443100Russian Federation

A homogenisation model for analysing the effect of micrometre pore sizes on the engineering moduli of elasticity of porous materials was *** the proposed model,the engineering coefficients of localization of total strains(LTs coefficients)are considered instead of the classical strain localization *** a pore,these coefficients represent the ratio of the sum of the strains in the volume of the pore to the sum of the strains in the volume of the porous *** estimate the elastic moduli of a material with an arbitrary pore size,it is sufficient to have information about the elastic moduli and the LTs coefficient of a material with one basic pore ***,in Eshelby's model of equivalent inclusion,a transition to LTs coefficient for material with arbitrary pore size is achieved,and its elasticity moduli are *** results for Young's modulus of porous titanium,with different sizes of spherical pores,completely conform with the experimental *** have obtained a model theoretic estimate of the upper bounds of Young's modulus of porous materials with infinitely small pore *** the spherical pores,the proposed assessment coincides with the upper limits of the Hashin-shtrikman bounds.

关键词： Elastic moduli Porous material Pore sizes

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Numerical modeling of destress blasting for strata separation

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第9期15卷 2238-2249页

作者： petr Konicek Tuo Chen Hani s.Mitri Institute of Geonics Czech Academy of SciencesOstrava70800Czech Republic Department of Mining and Materials Engineering McGill UniversityMontrealH3A 0E8Canada

Destress blasting(DB)implemented along the perimeter of safety pillars is a special application of destressing in coal longwall *** goal is to separate relatively more deformed mined areas from safety pillars,such as shaft pillars or cross-cut pillars,to reduce the transfer of high stresses to the protective *** case study aims to numerically simulate selected destress blasts in the Czech part of the Upper silesian Coal Basin and examine its impact on stress transfer to the safety pillar *** separate the area between the protective pillar and the longwall(LW),two fans of five 93-mm blast holes(length of 93e100 m)were drilled from the gate roads into the overburden *** set of blast holes was fired separately in two stages without time *** explosive charge(gelatin-type of explosive)of each stage is 3450 *** two DB stages were fired when the longwall face was approximately 158 m and 152 m away from the blast.A 3D mine-wide model is built and validated with in situ stress measured with *** and destressing in three 5-m thick coal seams are simulated in the *** modeling of DB is successfully conducted using a rock fragmentation factor a of 0.05 and a stress reduction/dissipation factor β of *** of transfer of additional stress from the mining area into the safety pillar is evaluated by comparison of yielding volume before and after *** is shown that yielding volume drops after DB by nearly 80%in the area of the destressing panel and near the safety shaft pillar.

关键词： Rockburst hazard Destress blasting(DB) strata separation safety pillar Numerical modeling Fragmentation factor stress dissipation factor Longwall mining

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Analytical solution of axisymmetric contact problem about indentation of a circular indenter into a soft functionally graded elastic layer

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Acta Mechanica sinica 2013年第2期29卷 196-201页

作者： sergey Volkov sergey Aizikovich Yue-sheng Wang Igor fedotov Research and Education Center "Materials" Don State Technical University south Federal University Research Institute of Mechanics and Applied Mathematics Institute of Engineering Mechanics Beijing Jiaotong University Department of Mathematical Technology Tshwane University of Technology

The paper addresses a contact problem of the theory of elasticity,i.e.,the penetration of a circular indenter with a flat base into a soft functionally graded elastic *** elastic properties of a functionally graded layer arbitrarily vary with depth,and the foundation is assumed to be elastic,yet much harder than a *** analytical solution is constructed,and it is shown that the solutions are asymptotically exact both for large and small values of characteristic dimensionless geometrical parameter of the *** examples are analyzed for the cases of monotonic and nonmonotonic variations of elastic *** results for the case of homogeneous layer are compared with the results for nondeformable foundation.

关键词： Contact problems·Indentation·Functionally graded layer

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Physics and applications of charged domain walls

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npj Computational Materials 2018年第1期4卷 119-129页

作者： petr s.Bednyakov Boris I.sturman Tomas sluka Alexander K.Tagantsev petr V.Yudin Institute of Physics Czech Academy of SciencesNa Slovance 218221 Prague 8Czech Republic Institute of Automation and Electrometry sB RAs Koptyug ave.1Novosibirsk 630090Russia CREAL3D sA Chemin du Paqueret 1 ACH-1025 Saint-SulpiceSwitzerland swiss Federal Institute of Technology(EPFL) CH-1015 LausanneSwitzerland Ioffe Institute 194021 St.PetersburgRussia

The charged domain wall is an ultrathin(typically nanosized)interface between two domains;it carries bound charge owing to a change of normal component of spontaneous polarization on crossing the *** contrast to hetero-interfaces between different materials,charged domain walls(CDWs)can be created,displaced,erased,and recreated again in the bulk of a *** of the bound charge with free carriers is often necessary for stability of CDWs,which can result in giant two-dimensional conductivity along the *** in nominally insulating ferroelectrics,the concentration of free carriers at the walls can approach metallic ***,CDWs can be viewed as ultrathin reconfigurable strongly conductive sheets embedded into the bulk of an insulating *** feature is highly attractive for future *** last decade was marked by a surge of research interest in *** resulted in numerous breakthroughs in controllable and reproducible fabrication of CDWs in different materials,in investigation of CDW properties and charge compensation mechanisms,in discovery of light-induced effects,and,finally,in detection of giant two-dimensional *** present review is aiming at a concise presentation of the main physical ideas behind CDWs and a brief overview of the most important theoretical and experimental findings in the field.

关键词： walls breakthrough nominal

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A Comparison of Experimental and Numerical studies Performed on a Low-Pressure Turbine Blade Cascade at High-speed Conditions, Low Reynolds Numbers and Various Turbulence Intensities

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Journal of Thermal science 2013年第5期22卷 413-423页

作者： Jan Michalek petr straka VZLU - Aerospace Research and Test Establishment Beranovych 130 19500 PragueCzech Republic

This paper focuses on a comparison of experimental and numerical investigations performed on a low-pressure mid-loaded turbine blade at operating conditions comprised of a wide range of Math numbers （from 0.5 - 1.1）, Reynolds numbers （from 0.4e＋5 - 3.0e＋5）, flow incidence （-15 - 15 degrees） and three levels of free-stream tur- bulence intensities （2, 5 and 10%）. The experimental part of the work was performed in a high-speed linear cas- cade wind tunnel. The increased levels of turbulence were achieved by a passive grid placed at the cascade inlet. A two-dimensional flow field at the center of the blade was traversed pitch-wise upstream and downstream the cascade by means of a five-bole probe and a needle pressure probe, respectively. The blade loading was measured using the surface pressure taps evenly deployed at the blade mid-span along the suction and the pressure side. The inlet turbulence was investigated using the constant temperature anemometer technique with a dual sensor probe. Experimentally evaluated values of turbulent kinetic energy and its dissipation rate were then used as inputs for the numerical simulations. An in-house code based on a system of the Favre-averaged Navier-stokes equation closed by a two-equation k-co turbulence model was adopted for the predictions. The code utilizes an algebraic model of bypass transition valid both for attached as for separated flows taking in account the effect of free-stream turbulence and pressure gradient. The resulting comparison was carried out in terms of the kinetic en- ergy loss coefficient, distributions of downstream wakes and blade velocity. Additionally a flow visualization was performed by means of the schlieren technique in order to provide a further understanding of the studied phe- nomena. A few selected cases with a particular interest in the attached and separated flow transition are compared and discussed.

关键词： low pressure turbine high-speed flow low Reynolds number flow separation transition RANs

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Hybrid LEs/RANs simulations of Compressible Flow in a Linear Cascade of Flat Blade Profiles

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Journal of Thermal science 2024年第5期33卷 1839-1850页

作者： Jaromír PRIHODA petr sTRAKA David sIMURDA petr sIDLOF Jan LEPICOVsKY Institute of Thermomechanics of the Czech Academy of sciences Dolejskova 1402/518200 Prague 5Czech Republic Aerospace Research and Test Centre Beranovych 13019905 PragueCzech Republic Technical University of Liberec Faculty of MechatronicsStudentska 246117 Liberec 1Czech Republic

The paper reports on 3D numerical simulations of unsteady compressible airflow in a blade cascade consisting of flat profiles using a hybrid LEs/RANs approach including a transition *** a first step towards simulation of blade flutter in turbomachinery,various incidence angle offsets of the middle blade were *** simulations were run for the flow regime characterized by outlet isentropic Mach number M_(is)=0.5and zero *** results of the LEs/RANs simulations(pressure and Mach number distributions)were compared to a baseline RANs model,and to experimental data measured in a high-speed wind *** numerical results show that both methods overpredict flow separation taking place at the leading *** this regard,the hybrid LEs/RANs method does not provide superior results compared to the traditional RANs ***,the LEs/RANs results also capture vortex shedding from the blunt trailing *** frequency of the trailing edge vortex shedding in CFD simulations matches perfectly the spectral peak recorded during wind tunnel measurements.

关键词： numerical simulation blade cascade hybrid LEs/RANs

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Numerical simulation of separated Flows in Channels

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Journal of Thermal science 2012年第2期21卷 145-153页

作者： petr Louda Jaromír Príhoda petr sváek Karel Kozel Czech Technical University in Prague Fac. of Mechanical Engineering Karlovo nám. 13 CZ-121 35 Praha 2 Institute of Thermomechanics As CR v.v.i. Dolejkova 5 CZ-182 00 Praha 8

The work deals with numerical modelling of turbulent flows in channels with an expansion of the cross-section where flow separation and reattachment occur. The performance of several eddy viscosity models and an explicit algebraic Reynolds stress model (EARsM) is studied. The used test cases are flows in channels with various backward facing steps where the step is perpendicular or inclined and the top wall is parallel or deflected. Furthermore, a channel with the circular ramp is considered. The numerical solution is achieved by the finite volume method or by the finite element method. The results of both numerical approaches are compared.

关键词： backward facing step flow EARsM model ssT model

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Visualization of Large Amount of spectra in Virtual Observatory Environment

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International Journal of Automation and computing 2014年第6期11卷 613-620页

作者： petr aloun David Andrei petr koda Ivan Zelinka Department of Computer science Faculty of Electrical Engineering and Computer Science VB-Technical University of Ostrava17.listopadu 15 708 33 Ostrava-Poruba Czech Republic Astronomical Institute of the Academy of sciences Fricova 298 251 65 Ondrejov Czech Republic

This paper presents overview of new features so far prepared for new version of spectral analysis tool sPLAT-VO that allows to retrieve a large amount of spectra(and other data) based on its characteristics by detailed querying a virtual observatory s resources. The overview is focused on enhancements of user experience, work with simple application messaging protocol(sAMP) and other interoperability that improves work with global list of spectra, plot window and analysis menu.

关键词： sPLAT-VO virtual observatory spectra simple application message protocol (sAMP) flexible image transport system (FITs)

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