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All-dielectric meta-optics and non-linear nanophotonics

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National Science Review 2018年第2期5卷 144-158页

作者： yuri Kivshar Nonlinear physics Center Australian National University ITMO University

Most optical metamaterials fabricated and studied to date employ metallic components resulting in significant losses, heat and overall low efficiencies. A new era of metamaterial physics is associated with all-dielectric meta-optics, which employs electric and magnetic Mie resonances of subwavelength particles with high refractive index for an optically induced magnetic response, thus underpinning a new approach to design and fabricate functional and practical metadevices. Here we review the recent developments in meta-optics and subwavelength dielectric photonics and demonstrate that the Mie resonances can play a crucial role in the realization of the unique functionalities of meta-atoms, also driving novel effects in the fields of metamaterials and nanophotonics. We discuss the recent research frontiers in all-dielectric meta-optics and uncover how Mie resonances can be employed for a flexible control of light with full phase and amplitude engineering, including unidirectional metadevices, highly transparent metasurfaces,non-linear nanophotonics and topological photonics.

关键词： nanophotonics Mie resonances meta-optics metasurfaces metamaterials

Approximations of the Fractional Integral and Numerical Solutions of Fractional Integral Equations

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Communications on Applied Mathematics and Computation 2021年第3期3卷 545-569页

作者： yuri Dimitrov Department of Mathematics and physics University of Forestry1756 SofiaBulgaria Institute of Mathematics and Informatics Bulgarian Academy of Sciences1113 SofiaBulgaria

In the present paper,we derive the asymptotic expansion formula for the trapezoidal approximation of the fractional *** use the expansion formula to obtain approximations for the fractional integral of ordersα,1+α,2+α,3+αand 4+α.The approximations are applied for computation of the numerical solutions of the ordinary fractional relaxation and the fractional oscillation equations expressed as fractional integral equations.

关键词： Fractional integral Trapezoidal approximation Fractional integral equation Finite-difference scheme

Strengthening of tungsten by coherent rhenium precipitates formed during low fluence irradiation

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Tungsten 2022年第1期4卷 20-27页

作者： yuri Osetsky Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA

Experimental data show that the accumulation of rhenium and osmium from transmutation reactions severely affect the microstructural evolution and property degradation of tungsten-based materials under neutron *** and modeling have confirmed that Re atom transport in W is by irradiation-produced migrating self-interstitial *** this diffusion mode in operation,a specific microstructure evolution is realized when at relatively low neutron fluence the Re-rich precipitates are formed,while the void and interstitial loop population development is suppressed,affecting the mechanical *** research shows the effect of small coherent Re-rich precipitates on the dislocation glide under stress,investigated using the molecular dynamics approach with empirical interatomic *** results are compared with an earlier simulation of void hardening in *** is demonstrated that small coherent Re-rich precipitates of less than 6 nm diameter represent relatively weak obstacles for moving edge *** implication of these results on the interpretation of experimental results is discussed.

关键词： Tungsten-rhenium alloys Molecular dynamics Re-rich precipitates Dislocation obstacle interaction Dislocation dynamics Obstacle strength

Attachment ability of combined biomimetic adhesive micro-textures of different shapes

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Friction 2023年第8期11卷 1430-1441页

作者： David BADLER yuri KLIGERMAN Haytam KASEM Faculty of Mechanical Engineering Technion-Israel Institute of TechnologyHaifa 3200003Israel Department of Mechanical Engineering Azrieli College of EngineeringJerusalem 9103501Israel

There are various potential applications of biomimetic adhesive solutions including climbing robotic systems,mobile sensor platforms,and biomedical applications such as patches for external *** resistance to both normal and tangential loads,however,is a critical issue that still needs to be *** animals have developed exceptional attachment mechanisms based on combined fibrillar elements of different shapes and *** investigation of combined biomimetic adhesive micro-textures on tribological performances such as adhesion,friction,and peeling resistance is needed to apply this idea to the design of an artificial texture having similar“biomimetic”*** the present study,we demonstrate that combinations of different shapes of biomimetic adhesive micro-textures show increased efficiency under different contact environments and enable long-term adhesive *** work sheds light on combinations of different element shapes inspired by nature and their adhesive efficiency as a function of the ratio of each biomimetic element,as well as their spatial repartition.

关键词： biomimetic micro-textures adhesion friction peeling

Electric resistivity of partially ionized plasma in the lower solar atmosphere

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Research in Astronomy and Astrophysics 2021年第9期21卷 193-201页

作者： Jongchul Chae yuri ELitvinenko Astronomy program Department of Physics and AstronomySeoul National UniversitySeoul 08826Korea Department of Mathematics University of WaikatoP.B.3105Hamilton 3240New Zealand

The lower solar atmosphere is a gravitationally stratified layer of partially ionized *** calculate the electric resistivity in the solar photosphere and chromosphere,which is the key parameter that controls the rate of magnetic reconnection in a Sweet-parker current *** calculation takes into account the collisions between ions and hydrogen atoms as well as the electron-ion collisions and the electron-hydrogen atom *** find that under the typical conditions of the quiet Sun,electric resistivity is determined mostly by the electron-hydrogen atom collisions in the photosphere,and mostly by the ion-hydrogen collisions,*** diffusion,in the *** magnetic reconnection events with strong magnetic fields,the ambipolar diffusion,however,may be insignificant because the heating by the reconnection itself may lead to the full ionization of hydrogen *** conclude that ambipolar diffusion may be the most important source of electric resistivity responsible for the magnetic flux cancelation and energy release in chromospheric current sheets that can keep a significant fraction of neutral hydrogen atoms.

关键词： plasmas atomic processes magnetohydrodynamics(MHD) Sun:atmosphere Sun:chromosphere

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Seeing is believing

Light(Science & Applications) 2022年第3期11卷 6-7页

作者： Sergey Krasikov yuri Kivshar Nonlinear physics Center Research School of PhysicsAustralian National UniversityCanberra ACT 2601Australia and School of Physics and EngineeringITMO UniversitySt.Petersburg197101Russia

Bound states in the continuum are realized in many optical systems as“dark states”,and their presence can be detected in the regime of leaky modes via resonances in *** the authors reveal previously unseen structure... 详细信息

关键词： states dielectric continuum

parallel Algorithm and Software for Image Inpainting via Sub-Riemannian Minimizers on the Group of Rototranslations

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Numerical Mathematics(Theory,Methods and Applications) 2013年第1期6卷 95-115页

作者： Alexey p.Mashtakov Andrei A.Ardentov yuri L.Sachkov program Systems Institute Pereslavl-ZalesskyRussia

The paper is devoted to an approach for image inpainting developed on the basis of neurogeometry of vision and sub-Riemannian *** is realized by completing damaged isophotes(level lines of brightness)by optimal curves for the left-invariant sub-Riemannian problem on the group of rototranslations(motions)of a plane SE(2).The approach is considered as anthropomorphic inpainting since these curves satisfy the variational principle discovered by neurogeometry of vision.A parallel algorithm and software to restore monochrome binary or halftone images represented as series of isophotes were *** approach and the algorithm for computation of completing arcs are presented in detail.

关键词： Image inpainting sub-Riemannian geometry neurogeometry of vision group of rototranslations of a plane parallel software

Air quality short-term control in an industrial region under adverse weather conditions

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Control Theory and Technology 2020年第3期18卷 257-268页

作者： yuri SKIBA David pARRA-CUEVARA Center for Atmospheric Sciences National Autonomous University of MexicoCircuito ExteriorCiudad UniversitariaCDMX04510Mexico

A new short-term optimal control of air quality in an industrial region during atmospheric inversions is *** goal is to prevent violation of health standard of air quality in a few monitored *** control establishes restrictions on the emission rates of industrial sources and includes the identification of the industrial sources violating(exceeding)the emission rates set by the *** control and identification are based on using solutions to an adjoint dispersion *** that show the convergence of the emission rates,prescribed by the control,to the original emission rates of the industrial sources are given(Theorems 4 and 5).These results ensure that the new emission rates of industrial sources(established by the control)will be as close as possible to the original emission rates throughout the entire period of application of the *** creates the minimum possible restrictions on the functioning of industrial *** highlight of the new control is the possibility of selecting special weights for each pollution source in the goal function that is *** weights are mainly aimed at reducing the intensity of emissions of the main sources of *** example demonstrates the ability of the new method.A similar approach can also be used to develop methods for cleaning water zones polluted by oil(the problem of bioremediation),and to prevent excessive pollution of urban areas with automobile emissions.

关键词： Dispersion model adjoint model adjoint estimates optimal control source detection

Meta-optics and bound states in the continuum

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Science Bulletin 2019年第12期64卷 836-842页

作者： Kirill Koshelev Andrey Bogdanov yuri Kivshar Nonlinear physics Centre Australian National UniversityCanberra ACT 2601Australia ITMO University St. Petersburg 197101Russia

We discuss the recent advances in meta-optics and nanophotonics associated with the physics of bound states in the continuum(BICs). Such resonant states appear due to a strong coupling between leaky modes in optical guiding structures being supported by subwavelength high-index dielectric Mieresonant nanoantennas or all-dielectric metasurfaces. First, we review briefly very recent developments in the BIC physics in application to isolated subwavelength particles. We pay a special attention to novel opportunities for nonlinear nanophotonics due to the large field enhancement inside the particle volume creating the resonant states with high-quality(high-Q) factors, the so-called quasi-BIC, that can be supported by the subwavelength particles. Second, we discuss novel applications of the BIC physics to alldielectric optical metasurfaces with broken-symmetry meta-atoms when tuning to the BIC conditions allows to enhance substantially the Q factor of the flat-optics dielectric structures. We also present the original results on nonlinear high-Q metasurfaces and predict that the frequency conversion efficiency can be boosted dramatically by smart engineering of the asymmetry parameter of dielectric metasurfaces in the vicinity of the quasi-BIC regime.

关键词： Bound states in the continuum Meta-optics Second-harmonic generation Nanoresonator Metasurfaces

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