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Bound states in the continuum and high-Q resonances supported by a dielectric ridge on a slab waveguide

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Photonics Research 2018年第11期6卷 1084-1093页

作者： EVGENI A.BEZUS DMITRY A.BYKOV leonid l.doskolovich Image Processing Systems Institute-Branch of the Federal Scientific Research Centre“Crystallography and Photonics”of the Russian Academy of Sciences 151 Molodogvardeyskaya St.Samara 443001Russia Samara National Research University 34 Moskovskoe ShosseSamara 443086Russia

We investigate the diffraction of the guided modes of a dielectric slab waveguide on a simple integrated structure consisting of a single dielectric ridge on the surface of the waveguide. Numerical simulations based on aperiodic rigorous coupled-wave analysis demonstrate the existence of sharp resonant features and bound states in the continuum(BICs) in the reflectance and transmittance spectra occurring at the oblique incidence of a transverseelectric(TE)-polarized guided mode on the ridge. Using the effective index method, we explain the resonances by the excitation of cross-polarized modes of the ridge. Formation of the BICs are confirmed using a theoretical model based on coupled-wave theory. The model suggests that the BICs occur due to the coupling of quasi-TE and quasi-transverse-magnetic modes of the structure. Simple analytical expressions for the angle of incidence and the ridge width predicting the location of the BICs are obtained. The existence of high-Q resonances and BICs enables using the considered integrated structure for sensing, transformation of optical signals, and enhancing nonlinear light–matter interactions. Due to the lorentzian line shape of the resonances near the BICs, the structure is also promising for filtering applications.

关键词： Bound states high-Q resonances slab waveguide TE BIC

Two-groove narrowband transmission filter integrated into a slab waveguide

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Photonics Research 2018年第1期9卷 61-65页

作者： leonid l. doskolovich EVGENI A. BEZUS AND DMITRY A. BYKOV Image Processing Systems Institute-Branch of the Federal Scientific Research Centre "Crystallography and Photonics" of Russian Academy of Sciences 151 Molodogvardeyskaya St. Samara 443001 Russia Samara National Research University 34 Moskovskoe Shosse Samara 443086 Russia

We propose a simple integrated narrowband filter consisting of two grooves on the surface of a slab *** filtering is performed in transmission at oblique incidence due to excitation of an eigenmode of the structure localized at a ridge cavity between the grooves. For the considered parameters, zero reflectance and unity transmittance are achieved at resonant conditions. The width and location of the transmittance peak can be controlled by changing the widths of the grooves and of the ridge, respectively. The proposed filter may find application in waveguide-integrated spectrometers.

关键词：平板波导滤波器通讯技术技术创新

Caspian Energy Ring: Prospective vision

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Global Energy Interconnection 2022年第5期5卷 461-471页

作者： Sergei Podkovalnikov lyudmila Chudinova Ivan l.Trofimov leonid Trofimov Melentiev Energy Systems Institute of Siberian Branch of the Russian Academy of Sciences 130Lermontov Str.Irkutsk664033Russia

This paper presents the results of a technical and economic optimization study of the prospects of the Caspian Energy Ring(CER),connecting power systems of Russia,countries of the Caucasus,Central Asia,and South *** CER,belonging partly to the emerging Asian Supergrid and partly to the existing European Supergrid,will become a bridge connecting these supergrids,laying the foundation for forming a global energy interconnection in the long *** expansion of carbon-free renewable and nuclear facilities,low-carbon gas-fired power plants,and traditional thermal and hydro energy sources within the CER were considered in this *** positive economic benefits of the creation of the CER are *** characteristics of the potential CER were also estimated.

关键词： Caspian Energy Ring Interstate electric power grids Transmission lines Installed capacity Power generation Economic viability.

Revisiting classical SIR modelling in light of the COVID-19 pandemic

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Infectious Disease Modelling 2023年第1期8卷 72-83页

作者： leonid Kalachev Erin l.landguth Jon Graham Mathematical Sciences University of MontanaMissoulaUSA Center for Population Health Research School of Public and Community Health SciencesUniversity of MontanaMissoulaUSA

Background:Classical infectious disease models during epidemics have widespread usage,from predicting the probability of new infections to developing vaccination plans for informing policy decisions and public health ***,it is important to correctly classify reported data and understand how this impacts estimation of model *** COVID-19 pandemic has provided an abundant amount of data that allow for thorough testing of disease modelling assumptions,as well as how we think about classical infectious disease modelling ***:We aim to assess the appropriateness of model parameter estimates and preiction results in classical infectious disease compartmental modelling frameworks given available data types(infected,active,quarantined,and recovered cases)for situations where just one data type is available to fit the *** main focus is on how model prediction results are dependent on data being assigned to the right model ***:We first use simulated data to explore parameter reliability and prediction capability with three formulations of the classical Susceptible-Infected-Removed(SIR)modelling *** then explore two applications with reported data to assess which data and models are sufficient for reliable model parameter estimation and prediction accuracy:a classical influenza outbreak in a boarding school in England and COVID-19 data from the fall of 2020 in Missoula County,Montana,***:We demonstrated the magnitude of parameter estimation errors and subsequent prediction errors resulting from data misclassification to model compartments with simulated *** showed that prediction accuracy in each formulation of the classical disease modelling framework was largely determined by correct data classification versus *** a classical example of influenza epidemics in an England boarding school,we argue that the Susceptible-Infected-Quarantined-Recovered(SIQR)model is more appropriat

关键词： Basic disease reproduction number Communicable disease control Coronavirus COVID-19 Disease transmission Epidemics Epidemiology Influenza data Mathematical models Montana SIR models

Shock standards Cu, Ag, Ir, and Pt in a wide pressure range

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Matter and Radiation at Extremes 2023年第4期8卷 37-46页

作者： leonid Burakovsky Dean l.Preston Scott D.Ramsey Charles E.Starrett Roy S.Baty los Alamos National laboratory Los AlamosNew Mexico 87545USA

Although they are polymorphic(multiphase)materials,both copper and silver are reliable Hugoniot standards,and thus it is necessary to establish an accurate analytic model of their principal *** we present analytic forms of their principal Hugoniots,as well as those of iridium and platinum,two“pusher”standards for shock-ramp experiments,over a wide range of *** are based on our new analytic model of the principal Hugoniot[Burakovsky et al.,***.132,215109(2022)].Comparison of the four Hugoniots with experimental and independent theoretical data(such data exist to very high pressures for both copper and silver)demonstrates excellent ***,the new model for copper and silver can be considered as providing the corresponding Hugoniot standards over a wide pressure *** also suggest an approach for calculating the Grüneisen parameter along the Hugoniot and apply it to copper as a prototype,and our results appear to be in good agreement with the available data.

关键词： silver copper analytic

Ignition of nanothermites by a laser diode pulse

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Defence Technology（防务技术） 2022年第2期18卷 194-204页

作者： Alexander Yu.Dolgoborodov Vladimir G.Kirilenko Michael A.Brazhnikov leonid I.Grishin Michael l.Kuskov Georgii E.Valyano Joint Institute for High Temperatures Russian Academy of SciencesRussia N.Semenov Federal Research Center for Chemical Physics Russian Academy of SciencesRussia National Research Nuclear University MEPhI Moscow Russia

Experimental investigation has been carried out for laser ignition and combustion of nanothermites based on aluminum and oxides of copper,bismuth and *** mixing of nanosized powders was used to produce *** thermite ignition,initiating laser pulse with a maximum intensity of 770 W/cm2 was generated by a laser diode with a wavelength of 808 *** ignition delay times,the minimum initiation energy density,and the average burning rate at various thermite densities and mass fractions of components were determined by recording the emission of radiation of the reaction products using a multichannel pyrometer jointly with a high-speed video *** effect of adding carbon black on the threshold parameters of a laser pulse was also *** on the obtained results,certain assumptions were put forward with regard to the mechanism of nanothermites’ignition by laser radiation and their *** particular,the assumptions were made on the two-stage process of the reaction initiation and jet burning mechanism of porous nanothermites.

关键词： Nanothermites laser ignition Burning rate Ignition delay

Gold Determination by Electrothermal Atomic Absorption Spectrometry After Preconcentration Using Natural Deep Eutectic Solvent Based on Menthol and Camphor

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Journal of Analysis and Testing 2023年第4期7卷 435-443页

作者： Valeriia Maksimova Varvara lapina leonid Martynov Andrey Shishov Olga Mokhodoeva Vernadsky Institute of Geochemistry and Analytical Chemistry Russian Academy of SciencesMoscow 119991Russian Federation lomonosov Institute of Fine Chemical Technologies MIREA-Russian Technological UniversityMoscow 119454Russian Federation Department of Analytical Chemistry Institute of ChemistrySaint-Petersburg State UniversitySt.Petersburg 199034Russian Federation

A novel analytical procedure for the determination of gold by electrothermal atomic absorption spectrometry combined with selective liquid-liquid extraction by natural deep eutectic solvents(NADESs)is *** extraction ability of the NADESs prepared using menthol,thymol and camphor toward gold in hydrochloric acid solutions was *** extraction efficiency was improved by optimizing the parameters including the composition of the NADES s,the volume ratio of organic and aqueous phases,kinetics,and acidity of the *** determination of gold was carried out by electrothermal atomic absorption spectrometry directly in the NADES s phase dissolved in isopropyl *** extraction recovery of gold from 1 mol/l HCl with the NADESs based on menthol and camphor mixed in a molar ratio 1:1 was 99.7%at an enrichment factor of *** limits of detection and quantification of the proposed procedure were 1μg/l and 3.3μg/l,respectively,with a relative standard deviation of less than 5%.The developed procedure was applied for determination of gold in the certified reference material of ore,environmental and waste waters.

关键词： Gold liquid-liquid extraction Menthol/camphor Natural deep eutectic solvents(NADESs) Electrothermal atomic absorption spectrometry(ETAAS)

Tractable XMl data exchange via relations

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Frontiers of Computer Science 2012年第3期6卷 243-263页

作者： Rada CHIRKOVA leonid lIBKIN Juan l. REUTTER Department of Computer Science North Carolina State University Raleigh NC 27606 USA School of Informatics University of Edinburgh Edinburgh EH8 9AB UK

We consider data exchange for XMl documents： given source and target schemas, a mapping between them, and a document conforming to the source schema, construct a target document and answer target queries in a way that is consistent with the source information. The problem has pri- marily been studied in the relational context, in which data- exchange systems have also been built. Since many XMl documents are stored in relations, it is natural to consider using a relational system for XMl data exchange. However, there is a complexity mismatch between query answering in relational and in XMl data exchange. This indicates that to make the use of relational systems pos- sible, restrictions have to be imposed on XMl schemas and mappings, as well as on XMl shredding schemes. We isolate a set of five requirements that must be ful- filled in order to have a faithful representation of the XMl data-exchange problem by a relational translation. We then demonstrate that these requirements naturally suggest the in- lining technique for data-exchange tasks. Our key contribu- tion is to provide shredding algorithms for schemas, docu- ments, mappings and queries, and demonstrate that they en- able us to correctly perform XMl data-exchange tasks using a relational system.

关键词： data exchange XMl XMl shredding inlining

Effectiveness of a new approach to minimally invasive surgery in palliative treatment of patients with distal malignant biliary obstruction

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World Journal of Gastrointestinal Surgery 2023年第4期15卷 698-711页

作者： Yaroslav M Susak leonid l Markulan Serhii M lobanov Roman Y Palitsya Mariia P Rudyk larysa M Skivka Department of Surgery with the Course of Emergency and Vascular Surgery O.O.Bogomolets National Medical UniversityKyiv 01601Ukraine Department of Abdominal Surgery National Military Medical Clinical Centre“Main Military Clinical Hospital”Kyiv 01133Ukraine Department of Microbiology and Immunology Taras Shevchenko National University of KyivKyiv 01033Ukraine

BACKGROUND Palliative endoscopic biliary drainage is the primary treatment option for the management of patients with jaundice which results from distal malignant biliary obstruction(DMBO).In this group of patients,decompression of the bile duct(BD)allows for pain reduction,symptom relief,chemotherapy administration,improved quality of life,and increased survival *** reduce the unfavorable effects of BD decompression,minimally invasive surgical techniques require continuous *** To develop a technique for internal-external biliary-jejunal drainage(IEBJD)and assess its effectiveness in comparison to other minimally invasive procedures in the palliative treatment of patients with *** A retrospective analysis of prospectively collected data was performed,which included 134 patients with DMBO who underwent palliative BD ***-jejunal drainage was developed to divert bile from the BD directly into the initial loops of the small intestine to prevent duodeno-biliary *** was carried out using percutaneous transhepatic *** transhepatic biliary drainage(PTBD),endoscopic retrograde biliary stenting(ERBS),and internal-external transpapillary biliary drainage (IETBD) were used for the treatment of studypatients. Endpoints of the study were the clinical success of the procedure, the frequency andnature of complications, and the cumulative survival *** were no significant differences in the frequency of minor complications between the studygroups. Significant complications occurred in 5 (17.2%) patients in the IEBJD group, in 16 (64.0%)in the ERBS group, in 9 (47.4%) in the IETBD group, and in 12 (17.4%) in the PTBD *** was the most common severe complication. In the IEBJD group, the course ofcholangitis was characterized by a delayed onset and shorter duration as compared to other studygroups. The cumulative survival rate of patients who underwent IEBJD was 2.6 times higher incomparison t

关键词： Distal malignant biliary obstruction Obstructive jaundice Bile duct decompression Palliative endoscopic biliary drainage Internal-external biliary-jejunal drainage