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International Journal of Smart and Nano Materials 2023年第1期14卷 21-35页

作者： pavel evgenjevich timoshenko Alexander Lerer Sergei Bernardovich Rochal pavel e.timoshenko Faculty of Physics Southern Federal UniversityRostov-on-DonRussia Southern Federal University Rostov-on-DonRussia

For single-walled carbon nanotubes(SWCNTs)with a length of 1-50μm,the surface plasmon-polariton(SPP)resonance is within the terahertz frequency range;therefore,SWCNT lattices can be used to design frequency-selective surface(FSS).A numerical model of electromagnetic wave diffraction on a two-dimensional periodic SWCNT lattice can be described by an integro-differential equation of the second-order with respect to the surface current along *** equation can be solved by the Bubnov-Galerkin *** dependence of reflecting and transmitting electromagnetic waves for FSSs near the SPP resonance is studied *** is shown that the resonances are within the lowerfrequency part of the terahertz *** also estimate the relaxa-tion frequency of an individual SWCNT and demonstrate the applic-ability of the Kubo formula for graphene conductivity to array of strips similar in size to SWCNTs under consideration.

关键词： Carbon nanotubes gratings graphene surface plasmon polaritons dielectric response functions

Finite-element analysis of scattering parameters of surface acoustic wave bandpass filter formed on barium titanate thin film

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International Journal of Smart and Nano Materials 2018年第2期9卷 88-98,I0002页

作者： pavel e.timoshenko Valery V.Kalinchuk Vladimir B.Shirokov Department of Nanotechnology Southern Federal UniversityRostov-on-DonRussia Southern Scientific Center RAS Rostov-on-DonRussia

The frequency dependence of scattering parameters of interdigital surface acoustic wave transducers placed on ferroelectric barium titanate(BaTiO_(3))epitaxial film in c-phase coated over magnesium oxide has been studied using the finite-element method(FeM)approach along with the perfectly matched layer(PML)*** interdigital transducer which has a comb-like structure with aluminum electrodes excites the mechanical *** distance between the fingers allows tuning the frequency properties of the wave *** magnesium oxide is taken as the *** two-dimensional model of two-port surface acoustic wave filter is created to calculate scattering parameters and to show how to design the fixture in COMSOL_(TM).Some practical computational challenges of finite element modeling of SAW devices in COMSOL_(TM)are *** effect of lattice misfit strain on acoustic properties of heterostructures of BaTiO_(3)epitaxial film in c-phase at room temperature is discussed in present article for two lowfrequency surface acoustic resonances.

关键词： SAW filters ferroelectrics thin films finite element method(FeM) COMSOL

Resonantly enhanced second-and third-harmonic generation in dielectric nonlinear metasurfaces

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Opto-electronic Advances 2024年第5期7卷 5-19页

作者： Ji Tong Wang pavel Tonkaev Kirill Koshelev Fangxing Lai Sergey Kruk Qinghai Song Yuri Kivshar Nicolae C.Panoiu Department of electronic and electrical engineering University College LondonLondon WC1E 7JEUnited Kingdom Nonlinear Physics Center Research School of PhysicsAustralian National UniversityCanberra ACT 2601Australia Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic SystemsHarbin Institute of TechnologyShenzhen 518055China Wuzhen Laboratory EGO Wuzhen Digital Economy Industrial ParkNo.925 Daole RoadTongxiangChina

Nonlinear dielectric metasurfaces provide a promising approach to control and manipulate frequency conversion optical processes at the nanoscale,thus facilitating both advances in fundamental research and the development of new practical applications in photonics,lasing,and ***,we employ symmetry-broken metasurfaces made of centrosymmetric amorphous silicon for resonantly enhanced second-and third-order nonlinear optical *** the rich physics of optical quasi-bound states in the continuum and guided mode resonances,we comprehensively study through rigorous numerical calculations the relative contribution of surface and bulk effects to second-harmonic generation(SHG)and the bulk contribution to third-harmonic generation(THG) from the ***,we experimentally achieve optical resonances with high quality factors,which greatly boosts light-matter interaction,resulting in about 550 times SHG enhancement and nearly 5000-fold increase of THG.A good agreement between theoretical predictions and experimental measurements is *** gain deeper insights into the physics of the investigated nonlinear optical processes,we further numerically study the relation between nonlinear emission and the structural asymmetry of the metasurface and reveal that the generated harmonic signals arising from linear sharp resonances are highly dependent on the asymmetry of the *** work suggests a fruitful strategy to enhance the harmonic generation and effectively control different orders of harmonics in all-dielectric metasurfaces,enabling the development of efficient active photonic nanodevices.

关键词： second-harmonic generation third-harmonic generation bound state in the continuum guided mode resonance all-dielectric metasurfaces nonlinear optics

Pulsed THz radiation under ultrafast optical discharge of vacuum photodiode

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Frontiers of Optoelectronics 2024年第2期 100-113页

作者： Aleksandr A.Ushakov Kseniia A.Mamaeva Leonid V.Seleznev Georgy e.Rizaev Vladimir Bukin Timophey V.Dolmatov pavel A.Chizhov Vladimir Bagdasarov Sergey V.Garnov Prokhorov General Physics Institute of the Russian Academy of Sciences Physical Institute Russian Academy of Sciences Moscow Institute of Physics and Technology Russian Institute for Scientific and Technical Information

In this paper, we first present an experimental demonstration of terahertz radiation pulse generation with energy up to 5 pJ under the electron emission during ultrafast optical discharge of a vacuum photodiode. We use a femtosecond optical excitation of metallic copper photocathode for the generation of ultrashort electron bunch and up to 45 kV/cm external electric field for the photo-emitted electron acceleration. Measurements of terahertz pulses energy as a function of emitted charge density, incidence angle of optical radiation and applied electric field have been provided. Spectral and polarization characteristics of generated terahertz pulses have also been studied. The proposed semi-analytical model and simulations in COMSOL Multiphysics prove the experimental data and allow for the optimization of experimental conditions aimed at flexible control of radiation parameters.

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Using Optical Tweezers to Study the Friction of the Red Blood Cells

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Advances in Bioscience and Biotechnology 2024年第2期15卷 100-111页

作者： edoukoua Jean Michel Konin pavel Yale Abadê Ange-Boris N’guessan Kouassi Benoit Kouakou Abaka Michel Kouacou eugene Megnassan Département des Sciences et Techniques Université Alassane Ouattara Bouaké C&#244te d’Ivoire Laboratoire d’Instrumentation Image et Spectroscopie (L2IS) Institut National Polytechnique Félix Houphou&#235t-Boigny (INPHB) Yamoussoukro C&#244te d’Ivoire Classes préparatoires aux grandes ecoles Université de San Pedro San Pedro C&#244te d’Ivoire Laboratoire de Physique Fondamentale et Appliquée Université Nangui Abrogoua (UNA) Abidjan C&#244te d’Ivoire

In the last two decades the study of red blood cell elasticity using optical tweezers has known a rise appearing in the scientific research with regard to the various works carried out. Despite the various work done, no study has been done so far to study the influence of friction on the red blood cell indentation response using optical tweezers. In this study, we have developed a new approach to determine the coefficient of friction as well as the frictional forces of the red blood cell. This approach therefore allowed us to simultaneously carry out the indentation and traction test, which allowed us to extract the interfacial properties of the microbead red blood cell couple, among other things, the friction coefficient. This property would be extremely important to investigate the survival and mechanical features of cells, which will be of great physiological and pathological significance. But taking into account the hypothesis of friction as defined by the isotropic Coulomb law. The experiment performed for this purpose is the Brinell Hardness Test (DB).

关键词： Friction Indentation Optical Tweezers Tribology Red Blood Cells

Influence of environmental predispositions on temperate mountain forest damage at different spatial scales during alternating drought and flood periods:case study in Hruby Jeseník Mts.(Czech Republic)

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Journal of Mountain Science 2022年第7期19卷 1931-1944页

作者： pavel SAMeC Romana KUDeLKOVA Petr LUKeS Ales KUCeRA pavel CUDLIN Global Change Research Institute CAS Bělidla 986/4aBrnoCZ-60300Czech Republic Department of Geology and Soil Science Faculty of Forestry and Wood TechnologyMendel University in BrnoZemědělská3BRNOCZ-61300Czech Republic Department of Geoinformatics Faculty of SciencePalacky University Olomouc17.listopadu 50OlomoucCZ-77900Czech Republic

Mountain forests are more prone to environmental predispositions(ePs)than submountain *** remote sensing of mountain forests enables instantaneous damage mapping,the investigation of the causes requires field ***,a local field or regionally modeled environmental characteristics influence remote data evaluation *** study focused on the evaluation of ePs effects damaging mountain forests between various spatial resolutions during environmental *** evaluation was divided into managed and natural forests in the Hruby Jeseník Mts.(Czech Republic;240-1491 m a.s.l.;50.082°N,17.231°e).Damage was assessed through the discrimination analysis of the normalised difference vegetation index(NDVI)by MODIS VI during alternating drought and flood periods *** local environmental influence was assessed using the discrimination function(DF)separability of forest damage in the training *** regional influence was assessed through map algebra estimated via the DF and a forest decline spatial model based on ePs from differences between risk growth conditions and biomass fuzzy ***,ePs and soil influenced forest NDVI at different *** management afflicted the NDVI more than the *** ePs afflicted the NDVI more than the soil *** winters and droughts had a greater influence on the NDVI than the flood events,with the winter of 2005/2006 inverting the DF direction,and the 2003 drought increasing differences in managed forest biomass and decreasing differences in natural forest *** than 50% of declining managed forests in the training sets occurred on Leptosols,Podzols and *** a regional scale,the soil influence was eliminated by multiple *** ePs influenced 96% of natural forest and 65% of managed forest,though managed forest damage was more *** mountain forest NDVI decline was dependent on both management and risk predispositions.

关键词： Mountain environment Forest damage types Canopy density Soil group Norway spruce(Picea abies)

Supersonic Flow Structure in the entrance Part of a Mixing Chamber of 2D Model ejector

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Journal of Thermal Science 2003年第4期12卷 344-349页

作者： Vaclav Dvorak pavel Safarik Technical University in Liberec Faculty of Mechanical Engineering Department of Power Engineering Equipment. Halkova 6461 17 Liberec Czech RepublicCzech Technical University in Prague Faculty of Mechanical Engineering 207.1 Institute of Fluid Dynamics and Power Engineering Division of Fluid Dynamics and Thermodynamics. Technicka 4 166 07 Praha 6 Czech Republic

The paper deals with experimental and numerical results of investigation into supersonic and transonic flow past a two-dimensional model ejector. Results of optical measurements show a flow structure and flow parameter development in the entrance part of the mixing chamber of the ejector. Numerical results are obtained by means of both the straight solution of shock waves in supersonic flow field using classical relations of parameters of shock waves and the Fluent 6 program. Results of numerical solutions are compared with experimental pictures of flow fields. Flow structure development in the mixing chamber is analysed in detail.

关键词： supersonic ejector shock waves shear layers mixing process boundary layer separation.

Analysis of the Caratheodory's Theorem on Dynamical System Trajectories Under Numerical Uncertainty

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Ieee/CAA Journal of Automatica Sinica 2018年第4期5卷 787-793页

作者： pavel Osinenko Grigory Devadze Stefan Streif Automatic Control and System Dynamics Laboratory Technische Universitat Chemnitz09107 ChemnitzGermany Ieee

The current work proposes a new and constructive proof for the Caratheodory's theorem on existence and uniqueness of trajectories of dynamical systems. The key concern is the numerical uncertainty, i.e., the discrepancy between mathematical proofs, algorithms, and their implementations, which may affect the correct functioning of a control system. Due to growing demands on security and compliance with specifications,correctness of the control system functioning is becoming ever more important. Since in both dynamical systems and many control design approaches, one of the central notions is the system trajectory, it is important to address existence and uniqueness of system trajectories in a way which incorporates numerical uncertainty. Constructive analysis is a particular approach to formalizing numerical uncertainty and is used as the basis of the current work. The major difficulties of guaranteeing existence and uniqueness of system trajectories arise in the case of systems and controllers which possess discontinuities in time,since classical solutions to initial value problems do not *** issue is addressed in Caratheodory's theorem. A particular constructive variant of the theorem is proven which covers a large class of problems found in practice.

关键词： Constructive analysis Caratheodory’s theorem dynamical systems

Mathematical Results In Quantum Physics Har/DVD

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Boosting the superconducting spin valve effect in a metallic superconductor/ferromagnet heterostructure

丛书名： With DVD-ROM

2011年

作者： pavel exner

ISBN: (数字)9789814350365

ISBN: (纸本)9814350354

The volume collects papers from talks given at QMath11 -- Mathematical Results in Quantum Physics, which was held in Hradec Kr??lov??, September 2010. These papers bring new and interesting results in quantum mechanics and information, quantum field theory, random systems, quantum chaos, as well as in the physics of social systems. Part of the contribution is dedicated to Ari Laptev on the occasion of his 60th birthday, in recognition of his mathematical results and his service to the community. The QMath conference series has played an important role in mathematical physics for more than two decades, typically attracting many of the best results achieved in the last three-year period, and the meeting in Hradec Kralove was no exception

关键词： qmath11 conference proceedings physics results quantum mathematical

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Nano Research 2016年第4期9卷 1005-1011页

作者： pavel V. Leksin Andrey A. Kamashev Joachim Schumann Vladislav e. Kataev Jurgen Thomas Bernd Buchner Ilgiz A. Garifullin Leibniz Institute for Solid State and Materials Research Dresden (IFW Dresden) DoO 1171 Dresden Germany Zavoisky Physical-Technical Institute Russian Academy of Sciences 420029 Kazan Russia Dresden University of Technology D-01062 Dresden Germany

Superconducting spin valves based on the superconductor/ferromagnet （S/F） proximity effect are considered to be a key element in the emerging field of superconducting spintronics. Here, we demonstrate the crucial role of the morphology of the superconducting layer in the operation of a multilayer S/F1/F2 spin valve. We study two types of superconducting spin valve heterostructures, with rough and with smooth superconducting layers, using transmission electron microscopy in combination with transport and magnetic characterization. We find that the quality of the S/F interface is not critical for the S/F proximity effect, as regards the suppression of the critical temperature of the S layer. However, it appears to be of paramount importance in the performance of the S/F1/F2 spin valve. As the morphology of the S layer changes from the form of overlapping islands to a smooth case, the magnitude of the conventional superconducting spin valve effect significantly increases. We attribute this dramatic effect to a homogenization of the Green function of the superconducting condensate over the S/F interface in the S/F1/F2 valve with a smooth surface of the S laver.

关键词： spintronics superconductivi ferromagnetism proximity effect