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Preface: Stars and interstellar medium

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Research in Astronomy and Astrophysics 2018年第8期18卷 1-3页

作者： nikolay n.samus Yan Li Institute of Astronomy Russian Academy of Sciences Yunnan Observatories Chinese Academy of Sciences

This issue presents proceedings of the ＂Stars and Interstellar Medium＂ section of the All- Russian Astronomical Conference VAK-2017. Sixteen papers （selected from about 70 talks） cover dif- ferent problems related... 详细信息

关键词： stars: binaries - ISM general - ISM clouds

The Fifth Edition of the General Catalogue of Variable Stars:experiences in the constellation Centaurus

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Research in Astronomy and Astrophysics 2018年第7期18卷 93-100页

作者： nikolay n.samus Elena n.Pastukhova Olga V.Durlevich Elena V.Kazarovets Institute of Astronomy Russian Academy of Sciences Sternberg Astronomical Institute Lomonosov Moscow University

We have recently announced that the General Catalogue of Variable Stars enters the stage of its fifth, purely electronic edition （GCVS 5.1）. We have included 1408 variable stars in the constellation Centaurus in this new version, GCVS 5.1. Working on this revision, we applied current possibilities from data mining, suggested new variability types for many variable stars and found new light elements for a large number of periodic variables. This paper describes the work completed during the preparation of GCVS 5.1 for Centaurus and discusses in detail a number of the most astrophysically significant cases.

关键词： catalogs - techniques photometric - stars variables general - binaries eclipsing

GSC 4560–02157: a new long-period eclipsing cataclysmic variable star

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Research in Astronomy and Astrophysics 2015年第7期15卷 1005-1011页

作者： Anton V.Khruslov Anatoly V.Kusakin Elena A.Barsukova Vitaly P.Goranskij Azamat F.Valeev nikolay n.samus Institute of Astronomy Russian Academy of Sciences Fesenkov Astrophysical Institute Special Astrophysical Observatory Russian Academy of Sciences Sternberg Astronomical Institute Lomonosov Moscow State University

We study the newly discovered variable star GSC 4560-02157. CCD photometry was performed in 2013-2014 at the Tien Shan Astronomical Observatory,and a spectrum was obtained with the 6-m telescope of the Special Astrophysical Observatory in June, 2014. GSC 4560-02157 is demonstrated to be an eclipsing variable star（P = 0.265359d）. All its flat-bottom primary minima are approximately at the same brightness level, but the star＇s out-of-eclipse brightness and brightness at secondary minima vary considerably（by up to 0.6m） from cycle to cycle. Moreover,there are short-term（time scale of 0.03-0.04 days） small-amplitude brightness variations out of eclipse. This behavior suggests a cataclysmic nature for the star, which is confirmed with a spectrum taken on 2014 June 5. The spectrum shows numerous emissions of the hydrogen Balmer series, He Ⅰ and He Ⅱ.

关键词： stars: dwarf novae -- binaries: eclipsing -- stars: individual: GSC 4560-02157

new variable stars from the photographic archive:semi-automated discoveries,attempts at automatic classification and the new field 104 Her

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Research in Astronomy and Astrophysics 2018年第8期18卷 29-40页

作者： Sergei V.Antipin Ignacio Becker Alexander A.Belinski Darya M.Kolesnikova Karim Pichara nikolay n.samus Kirill V.Sokolovsky Alia V.Zharova Alexandra M.Zubareva P.K.Sternberg Astronomical Institute M.V.Lomonosov Moscow University13University Ave.Moscow 119234Russia Pontificia Universidad Catolica de Chile SantiagoChile Institute of Astronomy Russian Academy of Sciences48Pyatnitskaya Str.Moscow 109017Russia Institute for Applied Computational Science Harvard UniversityCambridgeMAUSA IAASARS National Observatory of Athens15236 PenteliGreece Astro Space Center of Lebedev Physical Institute Profsoyuznaya Str.84/32Moscow 117997Russia

Using 172 plates taken with the 40-cm astrograph of the Sternberg Astronomical Institute （Lomonosov Moscow University） in 1976-1994 and digitized with a resolution of 2400dpi, we dis- covered and studied 275 new variable stars. We present the list of our new variables with all necessary information concerning their brightness variations. As in our earlier studies, the new discoveries show a rather large number of high-amplitude Delta Scuti variables, predicting that many stars of this type re- main not detected in the whole sky. We also performed automated classification of the newly discovered variable stars based on the Random Forest algorithm. The results of the automated classification were compared to traditional classification and showed that automated classification was possible even with noisy photographic data. However, further improvement of automated techniques is needed, which is especially important when considering the very large numbers of new discoveries expected from all-sky surveys.

关键词： techniques photometric

A new insight into the nature of seasonal variations in coordinate time series of GPS sites located near active faults

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Frontiers of Earth Science 2016年第3期10卷 560-569页

作者： Sergey V. TROFIMEnKO Victor G. BYKOV nikolay V. SHESTAKOV nikolay n. GRIB Hiroaki TAKAHASHI Institute of Tectonics and Geophysics Far Eastern Branch Russian Academy of Sciences Khabarovsk 680000 Russia north-Eastern Federal University Neryungri 678960 the Republic of Sakha (Yakutia) Russia Institute for Applied Mathematics Far Eastern Branch Russian Academy of Sciences Vladivostok 690041 Russia Far Eastern Federal University Vladivostok 690041 Russia Institute of Seismology and Volcanology Graduate School of Science Hokkaido University Sapporo 060-0810 Japan

This study provides new insights into the nature of seasonal variations in coordinate time series of GPS sites located near active faults and methods of their modeling. Monthly averaged coordinate time series were analyzed for several pairs of collocated GPS sites situated near the active fault intersection area, in close proximity to the central part of the northern boundary of the Amurian plate and the vicinity of the San Andreas Fault zone. It is concluded that the observed seasonal variations are best described by a breather function which is one of the solutions of the well-known sine-Gordon equation. The obtained results suggest that, in this case, the source of seasonal variations may be caused by the appearance of solitary strain waves in the fault intersection system, which may be qualitatively treated as standing waves of compression-extension of the geological medium. Based on statistical testing, the limits of applicability of the suggested model have been established.

关键词： space geodetic surveys oscillatory move-ments of crustal blocks seasonal variations Amurianmicroplate

EXISTEnCE OF SOLUTIOnS OF nTH-ORDER nOnLInEAR DIFFEREnCE EQUATIOnS WITH GEnERAL BOUnDARY COnDITIOnS

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Acta Mathematica Scientia 2020年第1期40卷 226-236页

作者： Alberto CABADA nikolay DIMITROV Departamento de Estatística Análise Matemática e OptimizaciónInstituto de MatemáticasFacultade de MatemáticasUniversidade de Santiago de CompostelaSantiago de CompostelaGaliciaSpain Depatment of Mathematics University of RuseRuse 7000Bulgaria

The aim of this paper is to prove the existence of one or multiple solutions of nonlinear difference equations coupled to a general set of boundary *** to do this,we construct a discrete operator whose fixed points coincide with the solutions of the problem we are looking ***,we introduce a strong positiveness condition on the related Green's function that allows us to construct suitable cones where to apply adequate fixed point *** we have the general existence result,we deduce,as a particular case,the existence of solutions of a second order difference equation with nonlocal perturbed Dirichlet conditions.

关键词： difference equation multiplicity of solutions Green's function positive solutions parameter dependence

Influence of frost weathering on the recession of surfaces of technogenic landforms in Yakutia

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Research in Cold and Arid Regions 2019年第4期11卷 257-266页

作者： Andrey E.Melnikov nikolay n.Grib Melnikov Permafrost Institute of the Siberian Branch of the Russian Academy of Sciences Yakutsk 677010Russia Technical Institute(branch)of M.K.Ammosov north-eastern Federal University Neryungri 678960Russia

The article assesses the influence of permafrost weathering on the rate of destruction of technogenic land forms,as exhibit ed on as illustrated by the railway embankment of the Amur Yakut mainline in the Sakha Republic(Yakutia).Studies were carried out on a railway section more than 375 km *** subsidence rate of the embankment slopes and structur al excavations was determined using laboratory methods that simulate various mechanisms of temperature(with a transi tion through 0℃)impact on *** the first time,a quantitative assessment of the influence of cryogenic weathering on the stability of the railway in the region belonging to the northern building climatic zone is *** the territory un der consideration,embankment rocks were experimentally determined to undergo more than 100 freezing and thawing cy cles during a *** the existing climatic conditions,cryogenic weathering actively affects the embankment of the railway to a depth of 30 *** of the embankment deformations detected during field observations are due to defects in the integrity of this particular *** size of the disintegrating layer of particular types of rock comprising the rail way embankment has been established as reaching 10 cm per *** 5 years following the formation of embankments comprising the upper structure of the railroad tracks,the physical and mechanical properties of rocks,which initially had a tensile strength for uniaxial compression in the range of 40 70 MPa,were reduced by more than 50%.According to the authors,the establishment of regional cryohypergenesis features is universal in nature and can be applied to solving a wide range of tasks related to the assessment and prediction of the degree of cryogenic transformation of rocks having different structural properties.

关键词： cryogenic weathering embankment railway subsidence rate Republic of Sakha Yakutia

Ion-conducting Membranes Based on Bacterial Cellulose nanofibers Modified by Poly(sodium acrylate-co-2-acrylamido-2-methylpropanesulfonic acid)

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Chinese Journal of Polymer Science 2024年第3期42卷 333-343,I0007页

作者： Elizaveta V.Batishcheva nikolay n.Smirnov natalya V.Bobrova Maria P.Sokolova Michael A.Smirnov Institute of Macromolecular Compounds Russian Academy of SciencesBolshoy pr.31Saint Petersburg 199004Russia

Green method for preparation of ion-conducting membranes(ICM) based on bacterial cellulose nanofibers(CnF) modified by a copolymer of sodium acrylate and 2-acrylamido-2-methylpropanesulfonic acid was elaborated. FTIR and nMR data confirmed grafting of polyacrylate onto cellulose surface. Formation of porous structure of the ICM was controlled by SEM and AFM. The maximal ionic conductivity of the membranes reaches 1.5 and 3.1 mS·cm^(-1)(60 ℃ and 98% relative humidity) when they are saturated with water or H_2SO_4(1 mol·L^(-1)) electrolyte,respectively. Prepared ICM was tested as a separator in a symmetrical supercapacitor with electrodes based on polyaniline hydrogel. The assembled cell demonstrate ability to operate at high current density up to 100 A·g^(-1) maintaining specific capacitance 165 F·g^(-1). Maximal specific capacitance of 289 F·g^(-1) was achieved at current density 1 A·g^(-1). Retaining of 90% of initial capacitance after 10000 of charge-discharge cycles proves high electrochemical stability of prepared ICM.

关键词： Bacterial cellulose Ion conductivity Porous membrane Supercapacitor

EXISTEnCE OF SOLUTIOnS OF nOnLOCAL PERTURBATIOnS OF DIRICHLET DISCRETE nOnLInEAR PROBLEMS

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Acta Mathematica Scientia 2017年第4期37卷 911-926页

作者： Alberto CABADA nikolay D.DIMITROV Instituto de Matemdticas Facultade de MatemdticasUniversidade de Santiago de Compostela15782 Santiago de CompostelaSpain Department of Mathematical Analysis University of Rousse7017 RousseBulgaria

This paper is devoted to the study of second order nonlinear difference equations. A nonlocal Perturbation of a Dirichlet Boundary Value Problem is considered. An exhaustive study of the related Green＇s function to the linear part is done. The exact expression of the function is given, moreover the range of parameter for which it has constant sign is obtained. Using this, some existence results for the nonlinear problem are deduced from monotone iterative techniques, the classical Krasnoselski fixed point theorem or by application of recent fixed point theorems that combine both theories.

关键词： Dirichlet boundary value problem nonlocal perturbations Green's function parameter dependence