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The Dependence of Stellar Activity Cycles on Effective Temperature

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Research in Astronomy and Astrophysics 2022年第12期22卷 198-210页

作者： Leonid Kitchatinov institute of Solar-Terrestrial Physics sb ras Lermontov Str.126AIrkutsk 664033Russia

This paper proposes the idea that the observed dependence of stellar activity cycles on rotation rate can be a manifestation of a stronger dependence on the effective temperature. Observational evidence is recalled and theoretical arguments are given for the presence of cyclic activity in the case of sufficiently slow rotation only. Slow rotation means proximity to the observed upper bound on the rotation period of solar-type stars. This maximum rotation period depends on temperature and shortens for hotter stars. The maximum rotation period is interpreted as the minimum rotation rate for operation of a large-scale dynamo. A combined model for differential rotation and the dynamo is applied to stars of different mass rotating with a rate slightly above the threshold rate for the *** show shorter dynamo cycles for hotter stars. As the hotter stars rotate faster, the computed cycles are also shorter for faster rotation. The observed smaller upper bound for rotation period of hotter stars can be explained by the larger threshold amplitude of the α-effect for onset of their dynamos: a larger α demands faster rotation. The amplitude of the(cycling) magnetic energy in the computations is proportional to the difference between the rotation period and its upper bound for the dynamo. Stars with moderately different rotation rates can differ significantly in super-criticality of their dynamos and therefore in their magnetic activity, as observed.

关键词： dynamo stars:activity stars:magnetic field stars:solar-type stars:rotation

Crystal Structures of Tris-dipivaloylmetanates of Tm^3＋ and Yb^3＋

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Chinese Journal of Structural Chemistry 2018年第4期37卷 640-644页

作者：黄燊 Sysoev Sergey Viktorovich Stabnikov Pavel Aleksandrovich Pervukhina Natalia Viktorovna Korolkov Ilia Viktorovich Mosyagina Svetlana Andreevna Nikolaev institute of Inorganic Chemistry SB RAS Novosibirsk State Technical University

A series of Ln（Ⅲ） dipivaloylmethanates Ln（dpm）3 has been obtained. The crystalstructures of Tm（dpm）3 （1） and Yb（dpm）3 （2） were determined by X-ray analysis at 200（2） K（Pmn2b Z = 2; a = 17.7509（8）, b = 10.5805（4）, c = 9.8380（4） A, V = 1847.7（1） A3 for （1） and a =17.7272（6）, b = 10.5882（3）, c = 9.8440（3） A, V= 1847.7（1） A^3 for （2））. These data complete thestructural evaluation of lanthanoid tris-dipivaloylmethanates. Compounds 1 and 2 are isostructuralto the complexes Ln（dpm）3 （Ln -- Er and Lu）. It is demonstrated that the volatility of tris-dipivaloylmethanates of rare earth elements increases from the complex of Lu to that of La.

关键词： dipivaloylmethanate Ln(Ⅲ) X-ray crystal structure volatility

Fossil history of Mesozoic weevils （Coleoptera： Curculionoidea）

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Insect Science 2012年第6期19卷 683-698页

作者： Andrei A. Legalov Laboratory of Phylogeny and Faunogenesis Institute of Systemafics and Ecology of Animals SB RAS Novosibirsk Russia

The first synopsis of Mesozoic weevils （Curculionoidea： Coleoptera） is pre- sented. Changes of family, genera and species abundance during the Mesozoic revealed three distributional patterns. The Jurassic （Karatau） fauna was dominated by the Nemony- chidae. During the Early Cretaceous （beginning at the Jurassic/Cretaceous border）, the Ithyceridae was the prevalent group with a significant role played by the Nemonychidae. In the Late Cretaceous （Cenomanian and Turonian）, the major groups were the Curculion- idae and Brentidae. Obviously, the change of weevil fauna during this period was due to the expansion of the angiosperms, which provided multiple niches in their vegetative and reproductive organs for weevil development.

关键词： Coleoptera Curculionoidea faunistic analysis fossil record Mesozoic,trophic levels

Surface alloying of Al films/Ti substrate based on high-current pulsed electron beams irradiation

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Rare Metals 2014年第2期33卷 155-160页

作者： Xian-Xiu Mei Jian-Qiang Fu Xiao-Na Li V.P.Rotshtein N.N.Koval Teng-Cai Ma Key Laboratory of Materials Modification by Laser Ion and Electron Beams Ministry of Education Dalian University of Technology institute of high current electronics Siberian Branch Russian Academy of Sciences

Ti–Al surface alloy was fabricated using a cyclic pulsed liquid-phase mixing of predeposited 100 nm Al film with a-Ti substrate by low-energy high-current electron beam. Electron probe micro-analysis（EPMA）,grazing incidence X-ray diffraction analysis（GIXRD）,transmission electron microscopy（TEM）, and nanoindentation were used to investigate the characterization of Ti–Al surface alloy. The experimental results show that the thickness of alloy layer is ＊3 lm, and the content of Al in the ＊1 lm thickness surface layer is ＊60 at%. The tetragonal TiAl and TiAl2intermetallics were synthesized at the top surface, which have nanocrystalline *** main phase formed in the ＊2.5 lm thick surface is TiAl, and there are few TiAl2and Ti3Al phase for the *** is enhanced in the alloyed layer. The nanohardness of Ti–Al surface alloy increased significantly compared with a-Ti substrate due to the nanostructure and enhanced dislocation. Since the e-beam remelted repeatedly, the Ti–Al surface alloy mixed sufficiently with Ti substrate. Moreover, there is no obvious boundary between the alloyed layer and substrate.

关键词： Ti–Al surface alloy layer high-current pulse electron beam irradiation Microstructural characterization

Sr-Isotopic Characteristic of the Typical Carbonate Neoproterozoic Siberia Sections

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地学前缘 2009年第S1期16卷 194-195页

作者： Vishnevskaya Irine Kuznetsov Anton Letnikova Elena institute of Geology and Mineralogy sb ras institute of Precambrian Geology and Geochronology ras

First Sr isotopic data for the type of Neoproterozoic carbonate sediments of the South Siberia are reported. Upper Riphean complex is represented by terrigenous -carbonate rocks of Tungysic Formation,Yenisey Mountain *** age of this Formation shows a wide range,from 924±40 Ma(K-Ar method)to 753±6 Ma(U-Pb method).Sediments of Zabit Formation,Bokson Series(East Sayan)and

关键词： Neoproterozoic carbonate sediments Sr isotopic chemostratigraphy

Structure and diversity dynamics of microbial communities at day and night:investigation of meromictic Lake Doroninskoe,Transbaikalia,Russia

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Journal of Oceanology and Limnology 2018年第6期36卷 1978-1992页

作者： Evgeniya MATYUGINA Natalia BELKOVA Svetlana BORZENKO Pavel LUKYANOV Marsel KABILOV Olga BATURINA Alexandra MARTYNOVA-VAN KLEY Armen NALIAN Aleksei PTITSYN institute of Natural Resources Ecology and Cryology SB RASChitaRussia Limnological institute sb ras IrkutskRussia institute of Chemical Biology and Fundamental Medicine NovosibirskRussia Stephen F.Austin State University TXUSA

Extreme environmental conditions are key factors in the formation of the structure and diversity of microbial communities. In meromictic ecosystems, extreme conditions and a stable stratification of physical, chemical and biological parameters lead to diversity and heterogeneity of microenvironments. Lake Doroninskoe is located in an extreme geographical area and diff ers from other known meromictic reservoirs of the world by a low level of illumination in the chemocline and a rare type of alkaline water in sedimentary rocks formed by evaporative concentration. To understand the key factors that shape the composition and structure of the microbial community, the macro-and micro-variations in space and time are of great importance. We investigated the short-term dynamics of the structure and diversity of microbial communities of the meromictic soda lake, Lake Doroninskoe, at day and night using highthroughput sequencing and bioinformatics. Metagenomic analysis of 16 S rRNA gene amplicons showed that the microbial communities had a high taxonomic diversity both at day and night. Sixteen bacterial and three archaeal phyla were identified. Proteobacteria were dominant and comprised 75% during the day, increasing to 90% at night. Metabolically stable denitrifying bacteria that were able to use a variety of alternative electron acceptors and electron donors were prevalent in Lake Doroninskoe. They belonged to the families Enterobacteriaceae(class Gammaproteobacteria) and Alcaligenaceae(class Betaproteobacteria). Statistically significant differences between day and night microbial communities were found. During the day, the microbial community was the most diverse. We discuss the peculiarities of the underexplored shortterm dynamics of the structure and diversity of the microbial communities of the meromictic soda Lake Doroninskoe, and propose topics for prospective studies.

关键词： bacterial diversity day-night dynamics meromixis Lake Doroninskoe high-throughput amplicon sequencing

The Study Internal Structure of the Annual Layers in Lake Sediments Using Synchrotron Radiation with X-ray Focusing Optics

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Acta Geologica Sinica(English Edition) 2014年第S1期88卷 5-6页

作者： Fedor DARIN Ivan KALUGIN Andrey DARIN Yakov RAKSHUN institute of Geology and Mineralogy sb ras institute of Nuclear Physics sb ras

1 Introduction Annually laminated(varve)sedimentary deposits are considered as one of the most important archives,since they offer precise temporal information(years)in combination with high time *** sediments of the ... 详细信息

关键词： varve .synchrotron radiation scanning X_ray fluorescence microanalysis focusing X-ray optics.

Emission of fused silica and KBr samples in the UV and visible spectral ranges under irradiation with 2.7 MeV electrons

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Matter and Radiation at Extremes 2022年第2期7卷 33-40页

作者： E.Kh.Baksht B.A.Alekseev A.G.Burachenko A.V.Vukolov A.P.Potylitsyn V.F.Tarasenko S.R.Uglov M.V.Shevelev institute of high current electronics sb ras 2/3 Akademichesky AvenueTomsk 634055Russia National Research Tomsk Polytechnic University Tomsk Polytechnic University30 Lenin AvenueTomsk 634050Russia

Fused silica and KBr samples were irradiated with a 2.7 MeV electron *** emission of fused silica and KBr samples in the UV and visible regions was studied under various experimental *** simulation of optical emission was carried out using the GEANT4 computer *** of energy spectra and angular distributions of the beam electrons were performed for different target *** results reveal the effect of scattering of the beam electrons on the angular distribution of Cherenkov radiation in fused silica samples with thicknesses exceeding the electron path length.

关键词： conditions. silica fused

PGE mineralization and melt composition of chromitites in Proterozoic ophiolite complexes of Eastern Sayan,Southern Siberia

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Geoscience Frontiers 2017年第4期8卷 721-731页

作者： O.Kiseleva S.Zhmodik V.S.Sobolev Institute of Geology and Mineralogy SB RAS Novosibirsk State University

The Ospino-Kitoi and Kharanur ultrabasic massifs represent the northern and southern ophiolite branches respectively of the Upper Onot ophiolitic nappe and they are located in the southeastern part of the Eastern Sayan（SEPES ophiolites）.Podiform chromitites with PGE mineralization occur as lensoid pods within dunites and rarely in harzburgites or serpentinized *** chromitites are classified into type I and type Ⅱ based on their Cr~#.Type I（Cr~# = 59-85） occurs in both northern and southern branches,whereas type Ⅱ（Cr~# = 76-90） occurs only in the northern *** contents range from ∑PGE 88-1189 ppb,Pt/Ir0.04-0.42 to ∑PGE 250-1700 ppb,Pt/Ir 0.03-0.25 for type I chromitites of the northern and southern branches *** type Ⅱ chromitites of the northern branch have ∑PGE contents higher than that of type Ⅰ（468-8617 ppb,Pt/Ir 0.1-0.33）.Parental melt compositions,in equilibrium with podiform chromitites,are in the range of boninitic melts and vary in Al_2O_3,TiO_2 and FeO/MgO contents from those of type I and type Ⅱ *** melt compositions for type Ⅰ chromitites are（Al_2O_3）_（melt） = 10.6—13.5 wt.%,（TiO_2）_（melt） = 0.01-0.44 wt.%,（Fe/Mg）_（melt） = 0.42-1.81;those for type Ⅱ chromitites are：（Al_2O_3）_（melt） = 7.8-10.5 wt.%,（TiO_2）_（melt） = 0.01-0.25 wt.%,（Fe/Mg）_（melt） = *** are further divided into Os-Ir-Ru（Ⅰ） and Pt-Pd（Ⅱ） based on their PGE *** type Ⅰ chromitites show only the Os-Ir-Ru pattern whereas type Ⅱ shows both Os-Ir-Ru and Pt-Pd *** mineralization in type Ⅰ chromitites is represented by the Os-Ir-Ru system,whereas in type Ⅱ it is represented by the Os-Ir-Ru-Rh-Pt *** results indicate that chromitites and PGE mineralization in the northern branch formed in a suprasubduction setting from a fluid-rich boninitic melt during active ***,the chromitites and PGE mineralization of the southern branch could have formed in a spreading zone *** peridotites have

关键词： Chromitites PGE mineralization Os-Ir-Ru and Pt-Pd patterns Ophiolite Eastern Sayan Parental melt