检索结果-南通市图书馆

Phase-matched third-harmonic generation via doubly resonant optical surface modes in 1D photonic crystals

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2016年第1期5卷 424-429页

作者： valery N Konopsky Elena v Alieva Sergey yu Alyatkin Alexey A Melnikov Sergey v Chekalin vladimir M Agranovich Institute of Spectroscopy Fizicheskaya5TroitskMoscow 142190Russia Moscow Institute of Physics and Technology Institutskiy per.9Dolgoprudny 141700Russia

Efficient nonlinear conversion requires that interacting optical waves maintain a consistent phase relationship when traveling in a medium despite its *** phase-matching,which is often used to compensate for the dispersion,is not applicable to optically isotropic nonlinear ***,we present a one-dimensional photonic crystal structure that allows the propagation of optical surface waves,both at the fundamental and third-harmonic frequencies,as an efficient medium for phasematched third-harmonic generation.A unique advantage of this structure is that the effective refractive indices for the surface waves are similar to the refractive index of air at both *** allows phase-matching between the first and third harmonics,and a visible collinear beam of the third harmonic is produced at the prism-coupled ***,these optical surface waves propagate over long distances even if a lossy nonlinear nanofilm is deposited onto the photonic crystal *** provide experimental results for third-harmonic generation at a wavelength of 410 nm for a bare dielectric Ta2O5/SiO2 multilayer structure and for the same structure coated with a 15-nm GaAs film.

关键词： nonlinear optics optical surface waves photonic crystals

Asymmetry ratio as a parameter of Eu^3＋ local environment in phosphors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2018年第5期36卷 474-481页

作者： Ilya E. Kolesnikov Alexey v. Povolotskiy Daria v. Mamonova Evgeny yu. Kolesnikov Alexey v. Kurochkin Erkki Lahderanta Mikhail D. Mikhailov Saint Petersburg State University 7/9 Universitetskaya nab. 199034 St.petersburg.Russia Lappeenranta University of Technology LUT Skinnarilankatu 34 53850 Lappeenranta Finland Scientific and Technological Institute of Optical Material Science VNTs S. I. Vavilov State Optical Institute Babushkina 36-1 192171 St. Petersburg Russia volga State University of Technology Lenin Sq. 3 424000 Yoshkar-Ola Russia

Study of the local environment of certain ion is quite a complex problem. Due to the unique luminescent properties, Eu^3＋ ions can be used as a structural probe. In this paper, effect of doping concentration,excitation wavelength and excitation mechanism on asymmetry ratio was systematically studied using Y3Al5O12：Eu^3＋, YvO4：Eu^3＋ and Y2O3：Eu^3＋nanophosphors. The asymmetry ratio gives information about the local surrounding and environmental changes around the Eu^3＋ ions. Asymmetry ratios of YAG：Eu^3＋and YvO4：Eu^3＋ nanopowders were calculated using standard technique and the obtained average values were found to be 0.75 and 8.2, respectively. However, it is found that standard method of asymmetry ratio calculation is suitable only for samples where all Eu^3＋ ions occupy one site. The ＂multisite model＂ of asymmetry ratio calculation was developed and used for Y2O3：Eu^3＋ nanocrystalline powders. Average value of asymmetry ratio for Eu^3＋ ions occupied ＂normal＂ sites is 6.0 and for Eu^3＋ ions occupied ＂defect＂sites is 2.3.

关键词： Eu3+ Oxide powders Luminescence Asymmetry ratio Structural probe Rare earths

Cerebral fat embolism following autologous fat injection in facial reconstruction:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2025年第2期13卷 50-58页

作者： Xiu-Ying Chen Fa Shen Chang Cheng yu-Han Wang Wen-Chao Cheng De-Zhi yuan Wen Huang Department of Neurology Chongqing Emergency Medical CenterChongqing University Central HospitalChongqing 400000China Department of Neurology Xinqiao HospitalThe Army Medical University(Third Military Medical University)Chongqing 400000China

BACKGROUND Autologous fat injection in facial reconstruction is a common cosmetic *** cerebral fat embolism(CFE)as a complication is rare,it carries serious health *** SUMMARY We present a case of a 29-year-old female patient who developed acute CFE following facial fat filling *** the surgery,the patient experienced symptoms including headache,nausea,vomiting,and difficulty breathing,which was followed by neurological symptoms such as slurred speech and left-sided *** physical examination and auxiliary investigations,including blood tests,head and neck computed tomography angiography,and cranial magnetic resonance diffusion-weighted imaging,were performed upon *** clinical diagnosis was acute cerebral embolism following facial fat filling *** included measures to improve cerebral circulation,dehydration for intracranial pressure reduction,nutritional support,and rehabilitation therapy for left limb *** patient showed a significant improvement in symptoms after 2 weeks of *** recovered left limb muscle strength to grade 5,had clear speech,and experienced complete relief of *** Our case highlights the potential occurrence of severe complications in patients undergoing fat injection in facial *** prevent these complications,plastic surgeons should enhance their professional knowledge and skills.

关键词： Cerebral fat embolism Mechanical thrombectomy Thrombolysis Steroid therapy Symptomatic treatment Case report

Chaotic Driven Tunneling in Rectangular Double-Well

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2006年第1期1卷 81-99页

作者： v.L.Golo yu.S.volkov Department of Mechanics and Mathematics Moscow State UniversityMoscow 119899 GSP-2Russia

We consider a charged particle confined in a one-dimensional rectangular doublewell potential,driven by an external periodic excitation at frequencyΩand with amplitude *** find that there is the regime of the parametric resonance due to the modulation of the amplitude A at the frequencyωprm,which results in the change in the population dynamics of the energy *** analysis relies on the Dirac system of Hamiltonian equations that are equivalent to the Schr¨odinger *** a finite dimensional approximation to the Dirac system,we construct the foliation of its phase space by subsets F_(ab)given by constraints a≤N_(0)≤b on the occupation probabilities N0 of the ground state,and describe the tunneling by frequenciesνab of the system’s visiting subsets F_(ab).The frequenciesνab determine the probability density and thus the Shannon entropy,which has the maximum value at the resonant frequencyω=ω*** reconstruction of the state-space of the system’s dynamics with the help of the Shaw-Takens method indicates that the quasi-periodic motion breaks down at the resonant valueωprm.

关键词： Tunneling double-well parametric resonance

Quasiparticle structure of superheavy nuclei in α-decay chains of -(285)Fl and -(291,293)Lv

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2017年第7期41卷 79-86页

作者： v.G.Kartavenko N.v.Antonenko A.N.Bezbakh L.A.Malov N.yu.Shirikova A.v.Sushkov R.v.Jolos Joint Institute for Nuclear Research 141980 Dubna Russia Mathematical Physics Department Tomsk Polytechnic University 634050 Tomsk Russia Dubna State University 141980 Dubna Russia

Two mean-field potentials, Woods-Saxon and Skyrme based potentials, are used to calculate the energies of low-lying one-quasiparticle states. The spectra of the low-lying states and the α-decay spectra of nuclei belonging to the α-decay chains of ^285Fl and ^291,293Lv are calculated and compared with the available experimental data. Dependence of the splitting of the pseudospin doublets and of the energies of the unique parity neutron one-quasiparticle states on the mean field potential are discussed. As shown, the α-decay spectra could be different in the α-decay chain and at the direct production of the nucleus in a fusion reaction.

关键词： structure of superheavy nuclei α-decay chain WS potential SHF approach

Phlogopite in mantle xenoliths and kimberlite from the Grib pipe,Arkhangelsk province,Russia:Evidence for multi-stage mantle metasomatism and origin of phlogopite in kimberlite

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2019年第5期10卷 1941-1959页

作者： A.v. Kargin L.v. Sazonova A.A. Nosova N.M. Lebedeva yu.A. Kostitsyn E.v. Kovalchuk v.v. Tretyachenko Ya.S. Tikhomirova Institute of Geology of Ore Deposits PetrographyMineralogyand GeochemistryRussian Academy of Sciences (IGEM RAS)MoscowRussia Lomonosov Moscow State University MoscowRussia vernadsky Institute of Geochemistry and Analytical Chemistry of Russian Academy of Sciences MoscowRussia AC ALROSA Research Geological Prospecting Enterprise ArkhangelskRussia

We present petrography and mineral chemistry for both phlogopite,from mantle-derived xenoliths (garnet peridotite,eclogite and clinopyroxene-phlogopite rocks) and for megacryst,macrocryst and groundmass flakes from the Grib kimberlite in the Arkhangelsk diamond province of Russia to provide new insights into multi-stage metasomatism in the subcratonic lithospheric mantle (SCLM) and the origin of phlogopite in *** on the analysed xenoliths,phlogopite is characterized by several *** first generation (Phl1) occurs as coarse,discrete grains within garnet peridotite and eclogite xenoliths and as a rock-forming mineral within clinopyroxene-phlogopite *** second phlogopite generation (Phl2) occurs as rims and outer zones that surround the Phl1 grains and as fine flakes within kimberlite-related veinlets filled with carbonate,serpentine,chlorite and *** garnet peridotite xenoliths,phlogopite occurs as overgrowths surrounding garnet porphyroblasts,within which phlogopite is associated with Cr-spinel and minor *** eclogite xenoliths,phlogopite occasionally associates with carbonate bearing veinlet ***,from the kimberlite,occurs as megacrysts,macrocrysts,microcrysts and fine flakes in the groundmass and matrix of kimberlitic *** phlogopite grains within the kimberlite are characterised by signs of deformation and form partly fragmented grains,which indicates that they are the disintegrated fragments of previously larger ***1,within the garnet peridotite and clinopyroxeneephlogopitexenoliths,is characterised bylow Ti and Cr contents (TiO292) typical of primary peridotite phlogopite in mantle peridotite xenoliths from global kimberlite *** formed during SCLM metasomatism that led to a transformation from garnet peridotite to clinopyroxene-phlogopite rocks and the crystallisation of phlogopite and high-Cr clinopyroxene megacrysts before the

关键词： Mantle metasomatism Kimberlite Phlogopite Mantle xenoliths Megacrysts

Thermal neutron flux produced by EAS at various altitudes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2013年第1期37卷 66-69页

作者： yu. v. Stenkin v. v. Alekseenko D. M. Gromushkin 刘烨马欣华赵静 Institute for Nuclear Research of Russian Academy of Sciences Moscow Physical Engineering Institute Hebei Normal University Institute of High Energy Physics of Chinese Academy of Sciences

The results of Monte-Carlo simulations of extensive air showers are presented to show the difference of the hadronic component content at various altitudes with the aim to choose an optimal altitude for a PRISMA-like experiment. The CORSIKA program for EAS simulations with QGSJET and GHEISHA models was used to calculate the number of hadrons reaching the observational level inside a circle of 50 m radius around the EAS axis. Then the number of neutrons produced by the hadronic component was calculated using an empirical relationship between the two components. We have tested the results with the ProtoPRISMA array at sea level, and recorded the neutrons which are consistent with the simulation results.

关键词： EAS detector neutrons altitudes

Synthetic morphogenesis:why reverse engineering should be prioritized

在线全文

学校读者我要写书评

暂无评论

Bio-Design and Manufacturing 2021年第2期4卷 429-431页

作者： v.N.Nikolenko M.yu Nikolayev M.Y.Sinelnikov Department of human anatomy first moscow state medical university(sechenov university)moscowrussian federation Department of normal and topographical anatomy lomonosov moscow state universitymoscowrussian federation Institute for regenerative medicine sechenov universitymoscowrussian federation

Dear Editor,In morphogenesis,the sequential execution of tissue arrangement depends on a vast array of signaling proteins and cellular *** mechanisms of such response have been identified:apoptosis,proliferation,fusion,adhesion,sorting,transition,folding,migration and *** combinations of these responses lead to the formation of various anatomical structures[1,2].

关键词： expansion. arrangement sorting

Enhanced electrochemical CO_(2)reduction coupled with urea oxidation using bifunctional atomically dispersed CuNi catalysts

在线全文

学校读者我要写书评

暂无评论

Nano Research 2025年第1期18卷 208-216页

作者： Wenjie Wu Haoyang Zhou Ying Liu Yifei Pan Qingqing Chen yu Zhang Junjie Mao Wenjie Ma Ping yu Beijing National Laboratory for Molecular Sciences Key Laboratory of Analytical Chemistry for Living BiosystemsInstitute of ChemistryChinese Academy of Sciences(CAS)Beijing 100190China College of Chemistry and Materials Science Anhui Normal UniversityWuhu 241002China University of Chinese Academy of Sciences Beijing 100049China

The electrochemical conversion of carbon dioxide(CO_(2))into chemical fuels represents a promising approach for addressing global carbon balance ***,this process is hindered by the kinetic limitations of anodic reactions,usually the oxygen evolution reaction,resulting in less efficient production of high value-added ***,we report an integrated electrocatalytic system that couples CO_(2)reduction reaction(CO_(2)RR)with urea oxidation reaction(UOR)using a bifunctional electrocatalyst with atomically dispersed dual-metal CuNi sites anchored on bamboo-like nitrogen-doped carbon nanotubes(CuNi-CNT),which were synthesized through a one-step pyrolysis *** bifunctional CuNi-CNT catalyst exhibits a near 100%CO Faraday efficiency for CO_(2)RR over a wide potential range and outstanding UOR performance with a negatively shifted potential of 210 mv at 10 mA·cm^(-2).In addition,we assemble a two-electrode electrolyzer using bifunctional CuNi-CNT-modified carbon fiber paper electrodes as both cathode and anode,capable of operating at a remarkably low cell voltage of 1.81 v at 10 mA·cm-2,significantly lower than conventional *** study provides a novel avenue to achieving an efficient carbon cycle with reduced electric power consumption.

关键词： electrochemical conversion bimetallic site catalyst bifunctional electrocatalyst carbon dioxide reduction urea oxidation