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Design of broadband terahertz vector and vortex beams: II. Holographic assessment

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Light(Advanced Manufacturing) 2022年第4期3卷 14-26页

作者： nikolay v.Petrov Bogdan Sokolenko Maksim S.Kulya Andrei Gorodetsky Aleksey v.Chernykh Digital and Display Holography Laboratory ITMO UniversitySt.Petersburg 197101Russia v.I.vernadsky Crimean Federal University Simferopol 295007Russia School of Physics and Astronomy University of BirminghamBirmingham B152TTUK

In this paper,we demonstrate the capabilities of the terahertz pulse time-domain holography in visualisation,simulation,and assessment of broadband THz vortex beam formation dynamics upon its shaping by elements of beam converter,and further propagation and *** adding Jones matrix formalism to describe broadband optical elements,we highlight the differences in the spatio-spectral and spatio-temporal structure of the formed vortex and vector beams dependence on the modulator used and visualise their modal *** influence of diffraction field structure from each element in the broadband vortex modulator is revealed in numerical simulation and the formed beams are analysed against the simplified Laguerre-Gaussian beam model.

关键词： Terahertz radiation vortex beams vector beams Achromatic wave plates Broadband terahertz radiation Digital holography Terahertz holography

Design of broadband terahertz vector and vortex beams: I. Review of materials and components

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Light(Advanced Manufacturing) 2022年第4期3卷 126-144页

In this paper,we review the existing approaches for vortex and vector beam shaping and generation in the terahertz frequency *** particular focus of this review is on the possibility of homogeneous topological charge formation in the ultra-wide spectral interval inherent to ultrashort terahertz *** review the available materials and components,analyse proposed and potentially possible solutions for broadband terahertz vortex and vector beam shaping,compare all developed approaches,and put forward a unified concept for constructing passive shapers of such beams from the existing component base.

关键词： Terahertz radiation vortex beams vector beams Achromatic wave plates Broadband terahertz radiation Digital holography Terahertz holography Total internal reflection Metasurface THz liquid crystals Geometric phase

（N-Z） Odd-Even Effect for the Non-Equilibrium Mechanism of （p, n） Reactions

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Journal of Physical Science and Application 2014年第3期4卷 166-176页

作者： nikolay v. Komilov Unemployed 9 Bolleana PI Athens 45701 USA

The neutron spectra and angular distributions from （p,n） reactions in the input proton energy range 6-25 Mev were analyzed. These are the old experimental data, however, re-analysis of these data reveals very interesting peculiarities which never have been discussed before. The high energetic part of neutron spectrum due to the direct mechanism changes considerably from one isotope to other. This difference was described with incorporation of two components which provide the ＂broad bump＂, or ＂step like＂ shape of neutron spectra at high energy. The properties of these components are： different shape, energy shift between them, and very strong fluctuation between different isotopes for ratio of cross sections connected with partial contribution. One may conclude that shape of non-compound neutron spectrum demonstrates very strong （N-Z） odd-even effect. The direct comparison of experimental data, and semi-empirical results with （p,n） spectra predicted by the EMPIRE code, gave evidence that the traditional approach cannot predict this effect. New finding may explain the ＂constant temperature＂ dependence for level density in mass range A-60 discussed in several investigations. These new experimental peculiarities were demonstrated, and it may be considered as reality. At the same time there is not consequent physical model for their explanation. The fact that spectrum shape is correlated with N-Z value may give a hint that discussed effects are connected with ＂halo-neutrons＂.

关键词： Nuclear reactions neutron emission direct mechanism odd-even effect.

A new species of Nanohyla(Anura:Microhylidae)from the lowland forests of southern vietnam

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Zoological Research 2023年第4期44卷 732-736页

作者： vladislav A.Gorin Alexey v.Trofimets Svetlana S.Gogoleva Le Xuan Dac nikolay A.Poyarkov Department of vertebrate Zoology Lomonosov Moscow State UniversityMoscow 119991Russia Joint vietnam-Russia Tropical Science and Technology Research Centre Cau GiayHanoi 122000Vietnam A.N.Severtsov Institute of Ecology and Evolution Russian Academy of SciencesMoscow 119071Russia

DEAR EDITOR,We describe a new species of Nanohyla from the Song Hinh Protected Forest in Phu Yen Province,southern vietnam,based on an integrative taxonomic *** new species represents a divergent lineage(16S rRNA gene uncorrected P-distance>5.3%),which clearly differs from any other Nanohyla species based on a series of morphological characters,most notably the presence of white spots on the top of its ***,Nanohyla albopunctata *** characterized by small body size(male snout-vent length(SvL)18.2-20.2 mm);moderately slender body habitus;rounded snout;distinct tympanum;rounded canthus rostralis;loreal region slightly concave;skin on dorsum tubercular,ventral surfaces smooth;mid-vertebral skin ridge and dorsomedial stripe absent;superciliary tubercles absent.

关键词： Morphological vietnam slightly

Self-healable and Robust Film Based on Electroactive Polymer Brush as Electrode for Flexible Supercapacitor

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Chinese Journal of Polymer Science 2024年第8期42卷 1049-1059页

作者： Maria P.Sokolova vitaly K.vorobiov nikolay N.Smirnov Ivan S.Kuryndin Natalya v.Bobrova Michael A.Smirnov Institute of Macromolecular Compounds Russian Academy of SciencesBolshoy pr.31Saint Petersburg 199004Russia

The aim of this study was to develop self-healable and robust elect roconductive film based on polyaniline copolymer for application as electrode in flexible *** this purpose,the electroconductive polymer brushes(EPB)was *** synthesis of EPB is based on graft polymerizations of acrylamide(AAm)on poly(vinyl alcohol)(PvA)with formation of PvA-PAAm polymer brush and subsequent graft copolymerization of aniline and p-phenylenediamine on PvA-PAAm resulting in formation of EPB with electroconducting copoly(aniline-co-pphenylenediamine)(PAPh DA).It was found that the ratio between PvA and PAAm at the first stage greatly influence the electrochemical performance of the *** films were prepared by casting of EPB solution with subsequent *** of electrical current distribution through the film with AFM reveal more uniform distribution of PAPhDA in EPB in comparison with reference PvA-PAPhDA and PAAm-PAPhDA *** was demonstrated that mechanical cha racteristics and electrical conductivity values of films restore at large extent after curring and self-healing under optimal relative humidity level(58%).The flexile supercapacitor cell with EPB film electrodes demon strate specific capacitance 602 mF·cm^(-2)at the current density of 1 mA·cm^(-2)and retention 94%of initial capacitance after 5000 charge/discharge cycles.

关键词： Polymer brush Polyaniline Flexible supercapacitor Self-healing Electroconducting film

Platinum quantum dots-decorated MXene-derived titanium dioxide nanowire/Ti_(3)C_(2) heterostructure for use in solar-driven gas-phase carbon dioxide reduction to yield value-added fuels

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Journal of Energy Chemistry 2023年第7期82卷 627-637,I0013页

作者： Kamakshaiah Charyulu Devarayapalli S.v.Prabhakar vattikuti Dong Jin kim Youngsu Lim Bolam kim Gyuhyeon kim Dae Sung Lee Department of Environmental Engineering Kyungpook National UniversityBuk-guDaegu 41566Republic of Korea Research Institute of Environmental Science&Technology Core Research InstituteKyungpook National UniversityBuk-guDaegu 41566Republic of Korea School of Mechanical Engineering Yeungnam UniversityGyeongsan 38541Republic of Korea School of Architecture CivilEnvironmental and Energy EngineeringKyungpook National UniversityBuk-guDaegu 41566Republic of Korea

Solar-driven photocatalytic CO_(2) reduction to produce valuable chemicals and fuels offers an attractive strategy in alleviating the energy *** quantum dots(PtQDs)with TiO_(2) nanowire(TiO_(2)NW)/Ti_(3)C_(2) MXene heterostructures(Pt-TiO_(2)NW/Ti_(3)C_(2)) with tight interfacial contacts between the various components were prepared at room temperature via oxidation *** incorporated PtQDs played crucial roles as electron conduction bridges supported by the cocatalyst effect,effectively enhancing the separation efficiencies of photoinduced electron/hole pairs and improving CO_(2) reduction under simulated solar light *** Pt-TiO_(2)NW/Ti_(3)C_(2) heterostructures exhibited remarkable carbon monoxide(CO)and methane(CH_(4)) production at respective rates of 38.14 and 36.15μmol g^(-1)after 10 h of simulated solar light irradiation,an apparent quantum yield of 1.68%,and 79.2%selectivity for *** photocatalytic activities of the Pt-TiO_(2) NW/Ti_(3)C_(2) heterostructures for CO_(2) reduction were significantly enhanced compared to those of TiO_(2)NW/Ti_(3)C_(2) and the single-component photocatalysts,and they exhibited remarkable stabilities even after five *** addition,the densities of states and electronic characteristics of Ti_(3)C_(2) MXene and Pt-TiO_(2)NW/Ti_(3)C_(2) were studied using density functional theory,and a synergistic mechanism of the improvement in CO_(2) photoreduction is proposed.

关键词： MXene CO_(2)reduction Density functional theory Quantum dot Photocatalyst

E-beam manipulation of Si atoms on graphene edges with an aberration-corrected scanning transmission electron microscope

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Nano Research 2018年第12期11卷 6217-6226页

作者： Ondrej Dyck Songkil kim Sergei v.Kalinin Stephen Jesse Center for Nanophase Materials Science Oak Ridge National LaboratoryOak RidgeTN 37830USA Institute for Functional Imaging of Materials Oak Ridge National LaboratoryOak RidgeTN 37830USA School of Mechanical Engineering Pusan National UniversityBusan 46241Republic of Korea

The burgeoning field of atomic-level material control holds great promise for future breakthroughs in quantum and memristive device manufacture and fundamental studies of atomic-scale chemistry. Realization of atom-by-atom control of matter represents a complex and ongoing challenge. Here, we explore the feasibility of controllable motion of dopant Si atoms at the edges of graphene via the sub-atomically focused electron beam in a scanning transmission electron microscope. We demonstrate that the graphene edges can be cleaned of Si atoms and then subsequently replenished from nearby source material. It is also shown how Si edge atoms may be “pushed” from the edge of a small hole into the bulk of the graphene lattice and from the bulk of the lattice back to the edge. This is accomplished through sputtering of the edge of the graphene lattice to bury or uncover Si dopant atoms. Finally, we demonstrate e-beam mediated hole healing and incorporation of dopant atoms. These experiments form an initial step toward general atomic-scale material control.

关键词： atomic manipulation graphene scanning transmission electron microscopy edge passivation silicon dopant electron beam dynamics

Application of pan-sharpening algorithm for correlative multimodal imaging using AFM-IR

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npj Computational Materials 2019年第1期5卷 714-722页

作者： nikolay Borodinov Natasha Bilkey Marcus Foston Anton v.Ievlev Alex Belianinov Stephen Jesse Rama K.vasudevan Sergei v.Kalinin Olga S.Ovchinnikova Center for Nanophase Materials Science Oak Ridge National LaboratoryOak RidgeTN 37831USA Department of Energy Environmental&Chemical EngineeringWashington University in St.LouisOne Brookings DriveSt.LouisMO 63130USA

The coupling of atomic force microscopy with infrared spectroscopy(AFM-IR)offers the unique capability to characterize the local chemical and physical makeup of a broad variety of materials with nanoscale ***,in order to fully utilize the measurement capability of AFM-IR,a three-dimensional dataset(2D map with a spectroscopic dimension)needs to be acquired,which is prohibitively time-consuming at the same spatial resolution of a regular AFM *** this paper,we provide a new approach to process spectral AFM-IR data based on a multicomponent pan-sharpening *** approach requires only a low spatial resolution spectral and a limited number of high spatial resolution single wavenumber chemical maps to generate a high spatial resolution hyperspectral image,greatly reducing data acquisition *** a result,we are able to generate highresolution maps of component distribution,produce chemical maps at any wavenumber available in the spectral range,and perform correlative analysis of the physical and chemical properties of the *** highlight our approach via imaging of plant cell walls as a model system and showcase the interplay between mechanical stiffness of the sample and its chemical *** believe our pan-sharpening approach can be more generally applied to different material classes to enable deeper understanding of that structure-property relationship at the nanoscale.

关键词： utilize modal walls

Al-matrix composite based on Al-Ca-Ni-La system additionally reinforced by L12 type nanoparticles

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Transactions of Nonferrous Metals Society of China 2020年第4期30卷 850-862页

作者： Torgom K.AKOPYAN nikolay A.BELOv Evgeniya A.NAUMOvA nikolay v.LETYAGIN Tat'yana A.SvIRIDOvA National University of Science and Technology MISiS 4 Leninsky pr.Moscow 119049Russia

The structure of the quaternary Al?(2?4)wt.%Ca?Ni?La system near the aluminum corner has been studied using computational analysis in the Thermo-Calc program and experimental studies(electron microscopy,microprobe analysis and X-ray diffraction).Based on the phase equilibria data obtained,the experimental projection of the liquidus surface and solid state phase-field distribution of the Al?Ca?Ni?La system have been *** studies reveal that the alloys with the 2?4 wt.%Ca,2?4 wt.%Ni and 1?3 wt.%La ranges have an ultra-fine hypoeutectic structure with 30%volume fraction of eutectic intermetallics,which allows one to classify these alloys as natural Al-matrix *** ultra-fine eutectic structure produces significant strengthening,the magnitude of which can be well described using the modified Orowan looping mechanism *** additives of Zr and Sc(0.2 and 0.1 wt.%,respectively)lead to significant strengthening(by^25%)due to the formation of L12 type phase(Al3(Zr,Sc))nanoparticles during annealing of the alloy at 350?400℃.Due to the high volume fraction of eutectic intermetallics,the new alloys have low coefficients of thermal expansion and high thermal stability of the structure and mechanical properties.

关键词： Al-Ca alloys eutectic intermetallics phase diagram rare earth element nanocomposite microstructure mechanical properties