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Dynamics of magnetic flux tubes and IR-variability of young stellar objects

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research in Astronomy and Astrophysics 2018年第8期18卷 13-20页

作者： Sergey Khaibrakhmanov Alexander Dudorov Andrey Sobolev Kourovka Astronomical Observatory Ural Federal University Theoretical Physics Department Chelyabinsk State University

We simulate the dynamics of slender magnetic flux tubes （MFTs） in the accretion disks of T Tauri stars. The dynamical equations of our model take into account aerodynamic and turbulent drag forces, and the radiative heat exchange between the MFT and ambient gas. The structure of the disk is calculated with the help of our MHD model of the accretion disks. We consider the MFTs formed at distances of 0.027 - 0.8 au from the star with various initial radii and plasma betas β0. The simulations show that MFTs with a weak magnetic field （β0 = 10） rise slowly with speeds less than the speed of sound. MFTs withβ0 = 1 form an outflowing magnetized corona above the disk. Strongly magnetized MFTs （β0 = 0.1） can cause outflows with velocities 20 - 50 km s-1. The tubes rise periodically over times from several days to several months according to our simulations. We propose that periodically rising MFTs can absorb stellar radiation and contribute to the IR-variability of young stellar objects.

关键词： accretion disks- instabilities- magnetohydrodynamics (MHD) - protoplanetary disks

Single and multi domain buckled germanene phases on Al(111)surface

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Nano research 2019年第12期12卷 2988-2996页

作者： Dmitriy A.Muzychenko Sergey I.Oreshkin Vladimir I.Panov Chris Van Haesendonck Andrey I.Oreshkin Faculty of Physics Lomonosov Moscow State University119991 MoscowRussia Sternberg Astronomical Institute Lomonosov Moscow State University119234 MoscowRussia Solid-State Physics and Magnetism Section KU LeuvenBE-3001 LeuvenBelgium

The simultaneous formati on of single domain(3×3)and multi domai n(√7×√7)R(±19.1°)germa nene phases on Al(111)surface in thesub-monolayer range was studied using seanning tunneling microscopy(STM)and density functional theory(DFT)based *** results revealed that both germa nene phases nu cleate and grow in dependently from each other and regardless of Al substratetemperature within significantly expanded range Ts=27-200℃.Our results unambiguously showed that STM images with hexagonalcontrast yield correct-resolved structure for both germanene phases,while honeycomb contrast is a result of an artificial tip-induced STM ***-principles calculations suggested atomic models with strongly buckled germanene(2×2)/Al(111)(3×3)and(√3×√3)R30°/Al(111)(√7×√7)R(±19.1°)with one of eight and one of six Ge atoms protruding upward respectively,that consistently describe the experimentally observed STM images both for single and multi domai n surface *** to the DFT based simulati ons both germa nene(2×2)and(√3×√3)R30°superstructures have a stretched lattice strain with respect to the ideal free-standing germa nene by 6.2%and 13.9%,***,numerous small domains separated by domain boundaries in the(√3×√3)R30°/Al(111)(√7×√7)R(±19.1°)germanenephase tend to reduce the surface energy and prevent the formation of extended single domains,in contrast to the(2×2)/Al(111)(3×3)***,our experimental results showed that the nucleation and growth of germa nene on Al(111)surface yield strong modifications of Alsurface even at room temperature(RT),which may be contributed to the formation of Al-Ge alloy due to Ge surface solid-states reactivitythat was ignored in recent *** is already evident from our present findings that the role of Al atoms in the formation of(3×3)and(√7×√7)R(±19.1°)germa nene phases is worthy to be carefully studied in the future,which could be an important knowledge for large-quantityfabrication of germane

关键词： germanene two-dimensional(2D)materials scanning tunneling microscopy density functional theory aluminum

Gold nanorods with a hematoporphyrin-loaded silica shell for dual-modality photodynamic and photothermal treatment of tumors in vivo

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Nano research 2014年第3期7卷 325-337页

作者： Georgy Terentyuk Elizaveta Panfilova Vitaly Khanadeev Daniil Chumakov Elina Genina Alexey Bashkatov Valery Tuchin Alia Bucharskaya Galina Maslyakova Nikolai Khlebtsov Boris Khlebtsov Saratov State University 83 Astrakhanskaya Saratov 410012 Russia Institute of Biochemistry and Physiology of Plants and Microorganisms 13 pr. Entuziastov Saratov 410049 Russia Institute of Precise Mechanics and Control of RAS 24 Rabochaya Saratov 410028 Russia Ulyanovsk State University 42 Lev Tolstoy Ulyanovsk 432017 Russia Optoelectronics andMeasurement Techniques Laboratory UniversityofOulu P.O. Box4500 Oulu FIN-90014 Finland Saratov State Medical University 112 Bolshaya Kazachia Saratov 410012 Russia

Nanocomposites （NCs） consisting of a gold nanorod core and a mesoporous silica shell doped with hematoporphyrin （HP） have been fabricated in order to improve the efficiency of cancer treatment by combining photothermal and photodynamic therapies （PDT ＋ PTT） in vivo. In addition to the long-wavelength plasmon resonance near 810-830 nm, the fabricated NCs exhibited a 400-nm absorbance peak corresponding to bound HP, generated singlet oxygen under 633-nm excitation near the 632.5-nm Q-band, and produced heat under a 808-nm near-infrared （NIR） laser irradiation. These modalities were used for a combined PDT ＋ PTT treatment of large （about 3 cm3） solid tumors in vivo with a xenorafted tumor rat model. NCs were directly injected into tumors and irradiated simultaneously with 633-nm and 808-nm lasers to stimulate the combined photodynamic and photothermal activities of NCs. The efficiency of the combined therapy was evaluated by optical coherence tomography, histological analysis, and by measurements of the tumor volume growth during a 21-day period. The NC-mediated PDT led to weak changes in tissue histology and to a moderate 20% decrease in the tumor volume. In contrast, the combined PDT ＋ PTT treatment resulted in the large-area tumor necrosis and led to dramatic decrease in the tumor volume.

关键词： nanocomposites gold nanorods mesoporous silica hematoporphyrin photodynarnic andphotothermal therapy

Composite Control of Nonlinear Singularly Perturbed Systems via Approximate Feedback Linearization

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International Journal of Automation and computing 2020年第4期17卷 610-620页

作者： Aleksey Kabanov Vasiliy Alchakov Sevastopol State University Sevastopol 299053Russian Federation

This article is devoted to the problem of composite control design for continuous nonlinear singularly perturbed(SP)system using approximate feedback linearization(AFL)*** essence of AFL method lies in the feedback linearization only of a certain part of the original nonlinear *** to AFL approach,we suggest to solve feedback linearization problems for continuous nonlinear SP system by reducing it to two feedback linearization problems for slow and fast subsystems *** resulting AFL control is constructed in the form of asymptotic composition(composite control).Standard procedure for the composite control design consists of the following steps:1)system decomposition,2)solution of control problem for fast subsystem,3)solution of control problem for slow subsystem,4)construction of the resulting control in the form of the composition of slow and fast *** main difficulty during system decomposition is associated with dynamics separation condition for nonlinear SP *** overcome this,we propose to change the sequence of the design procedure:1)solving the control problem for fast state variables part,2)system decomposition,3)solving the control problem for slow state variables part,4)construction of the resulting composite *** this way,fast feedback linearizing control is chosen so that the dynamics separation condition would be met and the fast subsystem would be *** application of the proposed approach is illustrated through several examples.

关键词： Approximate feedback linearization(AFL) composite control nonlinear singularly perturbed system order reduction decomposition

Optical high-resolution spectroscopic study of Tm^(3+) crystal-field levels in LiLuF_4

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Journal of Rare Earths 2009年第4期27卷 624-626页

作者： D.S.Pytalev S.A.Klimin M.N.Popova Institute of Spectroscopy Russian Academy of Sciences 5 Fizicheskaya St. Troitsk Moscow region 142190 Russia

We report on the fast high-resohition study of LiLuF4：Tm3＋. The accurate energy level scheme of Tm3＋ in the LiLuF4 matrix was obtained for the 3H6.5.4, 3F4.3.2, and ^1G4 multiplets. It was shown that electric-dipol... 详细信息

关键词： Fourier-transform spectroscopy Tm^3+ crystal-field levels LiLuF4 rare earths

Thin Film Nanocomposites for Gas Sensors

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稀有金属材料与工程 2006年第A03期35卷 33-35页

作者： E.S.Rembeza S.I.Rembeza B.M.Sinelnikov T.V.Svistova E.P.Domashevskaya Voronezh State University University sq.1394006 VoronezhRussia Voronezh State Technical University Moscow av.14394026 VoronezhRussia North Caucasian State Technical University Kulakov av.2355029 StavropolRussia

Nanocomposites on the base of thin films SnO_2 with additives of metal oxides such as SiO_2,ZrO_2,MnO_2 and others,were prepared by reactive ion-beam sputtering of metal target in the ambient of O_2+At,and then thermal treated at 500℃.Atomic composition and morphology of thin film nanocomposites were *** properties and gas sensitivity of nanocomposites were *** Was determined that the grain size of polycrystals depends on the film composition and can run down to 10 *** was found that temperature of maximal gas sensitivity of the films depends on their composition as well and it can be decreased by 100℃～150℃lower than temperature of maximal sensitivity of undoped films SnO_2.

关键词： nanocomposites metal oxides morphology electrical-physical properties gas sensitivity

Late Mesozoic topographic evolution of western Transbaikalia:Evidence for rapid geodynamic changes from the Mongol-Okhotsk collision to widespread rifting

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Geoscience Frontiers 2020年第5期11卷 1695-1709页

作者： A.V.Arzhannikova E.I.Demonterova M.Jolivet S.G.Arzhannikov E.A.Mikheeva A.V.Ivanov V.B.Khubanov L.A.Pavlova Institute of the Earth’s Crust Russian Academy of SciencesSiberian BranchIrkutskRussia Laboratoire Geosciences Rennes CNRS-UMR6118Universite de RennesRennesFrance Geological Institute Russian Academy of SciencesSiberian BranchUlan-UdeRussia A.P.Vinogradov Institute of Geochemistry Siberian Branch of the Russian Academy of SciencesIrkutskRussia

The Mesozoic geodynamic evolution of Transbaikalia has been largely controlled by the scissors-like closure of the Mongol-Okhotsk Ocean that separated Siberia from Mongolia-North China *** the oceanic closure,the tectonic evolution of that region was characterized by collisional uplift and subsequent extension that gave rise to the formation of metamorphic core *** complex tectonic setting prevailed simultaneously between 150 Ma and 110 Ma both in Transbaikalia,North Mongolia,and within the North China *** paleobotanical and paleontological data show that the oldest Mesozoic basins had formed in western Transbaikalia before the estimated age of extension *** no precise geochronological age is available for the onset of extension in *** Tugnuy Basin,as probably the oldest Mesozoic basin in western Transbaikalia,is a key obj ect to date the onset of extension and following changes in tectonic *** this study,U-Pb(LA-ICP-MS)dating of detrital zircons from three key Jurassic sediment formations of the Tugnuy Basin are used to identify the potential source areas of the sediments,understand the changes in sediment routing and provide insights on the topographic evolution of western *** results show several significant changes in tectonic regime after the closure of the Mongol-Okhotsk Ocean.A wide uplifted plateau formed during the closure of the Mongol-Okhotsk Ocean,determining the Early Jurassic drainage system reaching the AngaraVitim batholith to the north and shedding sediments to the continental margin to the *** following collisional event at the end of the Early Jurassic led to the uplift of the collision zone,which partially inverted the drainage system toward the North.A strike-slip displacement induced by the oblique collision initiated some of the early Transbaikalian depressions,such as the Tugnuy Basin at about 168 Ma.A phase of basin inversion,marked by folding and ero

关键词： U–Pb detrital zircons dating Topographic evolution Mongol–Okhotsk collision Transbaikalia

Paleoproterozoic,High-Metamorphic,Metasedimentary Units of Siberian Craton

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Acta Geologica Sinica(English Edition) 2009年第5期83卷 875-883页

作者： Lena URMANTSEVA Olga TURKINA Institute of Geology and Mineralogy Siberian BranchRussian Academy of SciencesNovosibirskRussia

Sensitive, high-resolution ion microprobe zircon U-Pb ages of Paleoproterozoic, high-grade, metasedimentary rocks from the south-western part of the Siberian Craton are reported. Early Precambrian, high-grade complexes, including garnet-biotite, hypersthene-biotite, and cordierite- bearing gneisses compose the Irkut terrane of the Sharyzhalgay Uplift. Protoliths of studied gneisses correspond to terrigenous sediments, ranging from greywacke to shale. The paragneiss model Nd ages of 2.4-3.1 Ga indicate Archean-to-Paleoproterozoic source provinces. Zircons from gneisses show corerim textures in cathodoluminescence （CL） image. Round or irregular shaped cores indicate detrital origin. Structureless rims with low Th/U are metamorphic in origin. The three age groups of detrital cores are：〉2.7, -2.3, and 1.95-2 Ga. The ages of metamorphic rims range from 1.86 to 1.85 Ga; therefore, the sediments were deposited between 1.95 and 1.86 Ga and derived from Archean and Paleoproterozoic source rocks. It should be noted that Paleoproterozoic metasedimentary rocks of the Irkut Block are not unique. High-grade metaterrigenous sediments, with model Nd ages ranging from 2.3 to 2.5 Ga, are widely distributed within the Aldan and Anabar Shields of the Siberian Craton. The same situation is observed in the North China Craton, where metasedimentary rocks contain detrital igneous zircon grains with ages ranging from 3 to 2.1 Ga （Wan et al., 2006）. All of these sedimentary units were subjected to Late Paleoproterozoic metamorphism. In the Siberian Craton, the Paleoproterozoic sedimentary deposits are possibly marked passive margins of the Early Precambrian crustal blocks, and their high-grade metamorphism was related to the consolidation of the Siberian Craton.

关键词： zircon sensitive high-resolution ion microprobe U-Pb dating metasedimentary rocks,Paleoproterozoic Siberian Craton

Passive vectoring of entomopathogenic fungus Beauveria bassiana among the wax moth Galleria mellonella larvae by the ectoparasitoid Habrobracon hebetor females

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Insect Science 2018年第4期25卷 643-654页

作者： Vadim Yu. Kryukov Natalia A. Kryukova Maksim V. Tyurin Olga N. Yaroslavtseva Viktor V. Glupov Institute of Systematics and Ecology of Animals Siberian Branch of russian Academy of Science Novosibirsk Russia

Females of the ectoparasitoid Habrobracon hebetor attack and envenomate numerous host individuals during oviposition. The vectoring of the entomopathogenic fungus Beauveria bassiana during the adhesion stage by ectoparasitoid females among the wax moth larvae Galleria mellonella was explored under laboratory conditions. Vectoring occurred both from infected parasitoids to wax moth larvae and from infected to healthy wax moth larvae by parasitoids. The efficacy of vectoring in both cases was dose dependent. Parasitoid females were unable to recognize infected larvae in a labyrinth test. In addition, the presence of H. hebetor females significantly （1.5-13 fold） increased the mycoses level in clusters of G. mellonella, with 40% of the larvae infected with ftmgal conidia. Envenomation by H. hebetor increased conidia germination on the cuticles of the wax moth larvae by 4.4 fold. An enhanced germination rate （2 fold） was registered in the n- hexane epicuticular extract of envenomated larvae compared to that of healthy larvae. Both envenomation and mycoses enhanced the phenoloxidase （PO） activity in the integument of G. mellonella and, in contrast, decreased the encapsulation rate in hemolymphs. We hypothesize that changes in the integument property and inhibition of cellular immunity provide the highest infection efficacy of entomopathogenic fungi with H. hebetor.

关键词： Galleria mellonella immunity integuments mycoses parasitoid vectoring