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Long-term photometric behavior of the eclipsing Z Cam-type dwarf nova AY Psc

Research in Astronomy and Astrophysics 2017年第6期17卷 67-76页

作者： Zhong-Tao Han Sheng-Bang Qian irina voloshina Li-Ying Zhu Yunnan Observatories Chinese Academy of Sciences Kunming 650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650216 China University of Chinese Academy of Sciences Beijing 100049 China Sternberg Astronomical Institute Moscow State University Universitetskij prospect 13 Moscow 119992 Russia

New eclipse timings of the Z Cam-type dwarf nova AY Psc were measured and the orbital ephemeris was revised. In addition, based on long-term AAVSO data, the outburst behaviors were also explored. Our analysis suggests that normal outbursts are quasi-periodic, with an amplitude of 2.5（4-0.1） mag and a period of - 18.3（4-0.7） d. The amplitude vs. recurrence-time relation ofAY Psc is discussed, and we conclude that this relation may represent general properties of dwarf nova outbursts. The observed standstill ends with an outburst, which is inconsistent with the general picture of Z Cam- type stars. This unusual behavior was considered to be related to mass-transfer outbursts. Moreover, the average luminosity Is brighter during standstills than during outburst cycles. The changes in brightness mark variations in M2 due to the fact that the disk of AY Psc is nearly steady state.M2 value was limited to the range from 6.35 × 10-9 to 1.18 × 10-8 M yr-1. More detailed examination shows that there are a few small outbursts present during standstills. These events with amplitudes of - 0.5 - 0.9 mag are very similar to the stunted outbursts reported in some nova-like cataclysmic variables. We discussed several possible mechanisms and suggested that the most reasonable mechanism for these stunted outbursts is a changing mass-transfer rate.

关键词： binaries close - stars cataclysmic variables - stars individual (AY Psc)

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Physical parameters and orbital period variation of a newly discovered cataclysmic variable GSC 4560-02157

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Research in Astronomy and Astrophysics 2016年第10期16卷 55-62页

作者： Zhong-Tao Han Sheng-Bang Qian irina voloshina Vladimir G. Metlov Li-Ying Zhu Lin-Jia Li Yunnan Observatories Chinese Academy of Sciences Kunming 650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650216China University of Chinese Academy of Sciences Beijing 100049 China Sternberg Astronomical Institute Moscow State University Universitetskij prospect 13 Moscow 119992 Russia

GSC 4560-02157 is a new eclipsing cataclysmic variable with an orbital period of 0.265359 days. By using the published V- and R-band data together with our observations, we discovered that the O - C curve of GSC 4560-02157 may show a cyclic variation with a period of 3.51 years and an amplitude of 1.40 min. If this variation is caused by a light travel-time effect via the existence of a third body, then its mass can be derived as M3 sin i1≈ 91.08 Mjup, and it should be a low-mass star. In addition, several physical parameters were measured. The color of the secondary star was determined to be V - R = 0.77（±0.03） which corresponds to a spectral type of K2-3. The secondary star＇s mass was estimated as M2 = 0.73（±0.02） Mo by combing the derived V - R value around phase 0 with the assumption that it obeys the mass-luminosity relation for main sequence stars. This mass is consistent with the mass-period relation for CV donor stars. For the white dwarf, the eclipse durations and contacts of the white dwarf yield an upper limit on the white dwarf＇s radius corresponding to a lower limit on mass of M1 ≈ 0.501 M⊙. The overestimated radius and previously published spectral data indicate that the boundary layer may have a very high temperature.

关键词： techniques: photometric -- stars: binaries: cataclysmic variables -- stars: individual:GSC 4560-02157

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Optimization of the Dressing Parameters in Cylindrical Grinding Based on a Generalized Utility Function

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Chinese Journal of Mechanical Engineering 2016年第1期29卷 63-73页

作者： ALEKSANDROVA irina Department of Mechanical Engineering Equipment and Technologies Technical University of Gabrovo

The existing studies, concerning the dressing process, focus on the major influence of the dressing conditions on the grinding response variables. However, the choice of the dressing conditions is often made, based on the experience of the qualified staff or using data from reference books. The optimal dressing parameters, which are only valid for the particular methods and dressing and grinding conditions, are also used. The paper presents a methodology for optimization of the dressing parameters in cylindrical grinding. The generalized utility function has been chosen as an optimization parameter. It is a complex indicator determining the economic, dynamic and manufacturing characteristics of the grinding process. The developed methodology is implemented for the dressing of aluminium oxide grinding wheels by using experimental diamond roller dressers with different grit sizes made of medium- and high-strength synthetic diamonds type AC32 and AC80. To solve the optimization problem, a model of the generalized utility function is created which reflects the complex impact of dressing parameters. The model is built based on the results from the conducted complex study and modeling of the grinding wheel lifetime, cutting ability, production rate and cutting forces during grinding. They are closely related to the dressing conditions （dressing speed ratio, radial in-feed of the diamond roller dresser and dress-out time）, the diamond roller dresser grit size/grinding wheel grit size ratio, the type of synthetic diamonds and the direction of dressing. Some dressing parameters are determined for which the generalized utility fimction has a maximum and which guarantee an optimum combination of the following： the lifetime and cutting ability of the abrasive wheels, the tangential cutting force magnitude and the production rate of the grinding process. The results obtained prove the possibility of control and optimization of grinding by selecting particular dressing parameters

关键词： dressing conditions cylindrical grinding diamond roller dresser generalized utility function based optimization

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Infl uence of fire on soil temperatures of pine forests of the middle taiga,central Siberia,Russia

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Journal of Forestry Research 2021年第3期32卷 1139-1145页

作者： irina Nikolaevna Bezkorovaynaya Pavel Albertovich Tarasov irina Gennadievna Gette irina Andreevna Mogilnikova Siberian Federal University 79 SvobodnyKrasnoyarskRussia 660041 Reshetnev Siberian State University of Science and Technology 31 Krasnoyarsky Rabochy AvKrasnoyarskRussia 660037

Temperatures of sandy podzols of middle taiga pine forests with moss and lichen ground cover were analyzed which had been exposed to ground fires of low to medium *** general,temperatures in lichen and moss plots of the pine forests under study,are close to each similar,but in the first year after a fire a noticeable contrast was *** reasons are an increase in the amplitude of daily temperatures on the soil surface and stronger heating of upper mineral *** in the mineral layer with depths up to 30 cm depend on the thickness of the forest fl *** of the results show that the duration of postfire effects in pine forests with sandy podzols is determined by a number of factors:the intensity of the fire,the degree of erosion of the ground cover and litter,and the recovery rate of these components.

关键词： Ground fire Pine forests Soil temperature

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Early Jurassic Climate Warming in Eastern Siberia: First Macrofloristic Evidence from Irkutsk Basin, Russia

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 1035-1050页

作者： Andrey FROLOV irina MASHCHUK Institute of the Earth's Crust Siberian Branch of the Russian Academy of SciencesIrkutsk664033Russia

Numerous new records of Ferganiella, Podozamites, and Schidolepium, including a new species, Ferganiella ivantsovii sp. nov., are described from the Early Jurassic(Toarcian) Middle Subformation of the Prisayan Formation from the Euro-Sinian paleofloristic region in the Irkutsk Basin, Eastern Siberia, Russia. An analysis of the paleogeographic distribution of Ferganiella and Podozamites shows that both genera were the most diverse and numerous in the East Asian province of the Euro-Sinian region and in the Northern Chinese province of the Siberian region during the Early and Middle Jurassic. These phytochoria were located in the subtropical and temperate subtropical climate zones, which allows us to consider Ferganiella and Podozamites as thermophilic plants, which are important indicators of the Early Toarcian climatic optimum. Their abundance in the Irkutsk Basin thus may indicate Early Toarcian warming;further abundant Schidolepium cones, which produced Araucariacites pollen, typical for Euro-Sinian flora complement the scenario. Thus, the new finds are the first macrofloristic indicators of the Toarcian climatic optimum in the Irkutsk Basin.

关键词： paleobotany Ferganiella Podozamites Schidolepium Toarcian climatic optimum paleobiogeography Siberian paleofloristic region Irkutsk

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Two New Species of Eretmophyllum(Ginkgoales)from the Jurassic of Eastern Siberia

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Acta Geologica Sinica(English Edition) 2023年第4期97卷 1014-1025页

作者： Andrey FROLOV irina MASHCHUK Institute of the Earth's Crust Siberian Branch of the Russian Academy of SciencesIrkutsk 664033Russia

Two new species of Eretmophyllum Thomas are described from the lower(Toarcian)and upper(Aalenian)Prisayan Formation of the Irkutsk Basin,Eastern Siberia,Russia based on distinct morphological and cuticular features of the leaves that distinguish them from other species of the *** polypapillosum *** characterized by the presence of 2-3 papillae on the lower and upper epidermis of ordinary ***,the leaf burials of *** *** that it preferred mesophilic forests developed on river terraces and/or low *** yershowskiensis *** represented exclusively by leaf cuticles extracted by coal maceration,and it probably inhabited the low banks of peat *** presence of the genus Eretmophyllum in the Early Jurassic of France and Eastern Siberia shows that it was already widespread in the territory of Eurasia,distributed from Western Europe to Eastern *** indicates the possible existence of Eretmophyllum species elsewhere in the Early Jurassic such as Central Asia and Northwest China.

关键词： paleobotany ginkgoalean taxonomy paleophytogeography paleoecology leaf cuticles Irkutsk Coal Basin

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Truncation Errors,Exact and Heuristic Stability Analysis of Two-Relaxation-Times Lattice Boltzmann Schemes for Anisotropic Advection-Diffusion Equation

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Communications in Computational Physics 2012年第5期11卷 1439-1502页

作者： irina Ginzburg IRSTEA Antony Regional CentreHBAN1 rue Pierre-Gilles de Gennes CS 1003092761 Antony cedexFrance

This paper establishes relations between the stability and the high-order truncated corrections for modeling of the mass conservation equation with the tworelaxation-times(TRT)collision *** we propose a simple method to derive the truncation errors from the exact,central-difference type,recurrence equations of the TRT *** also supply its equivalent three-time-level discretization *** different relationships of the two relaxation rates nullify the third(advection)and fourth(pure diffusion)truncation errors,for any linear equilibrium and any velocity ***,the two relaxation times alone cannot remove the leading-order advection-diffusion error,because of the intrinsic fourth-order numerical *** truncation analysis is carefully verified for the evolution of concentration waves with the anisotropic diffusion *** anisotropic equilibrium functions are presented in a simple but general form,suitable for the minimal velocity sets and the d2Q9,d3Q13,d3Q15 and d3Q19 velocity *** anisotropic schemes are complemented by their exact necessary von Neumann stability conditions and equivalent finite-difference *** sufficient stability conditions are proposed for the most stable(OTRT)family,which enables modeling at any Peclet numbers with the same velocity *** heuristic stability analysis of the fourth-order truncated corrections extends the optimal stability to larger relationships of the two relaxation rates,in agreementwith the exact(one-dimensional)and numerical(multi-dimensional)stability analysis.A special attention is put on the choice of the equilibrium *** combining accuracy and stability predictions,several strategies for selecting the relaxation and free-tunable equilibrium parameters are suggested and applied to the evolution of the Gaussian hill.

关键词： Two-relaxation-times Lattice Boltzmann scheme AADE truncation errors von Neumann stability analysis numerical diffusion heuristic stability analysis

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The latest geodynamics in Asia:Synthesis of data on volcanic evolution,lithosphere motion,and mantle velocities in the Baikal-Mongolian region

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Geoscience Frontiers 2017年第4期8卷 733-752页

作者： Sergei Rasskazov irina Chuvashova Institute of the Earth's Crust Siberian Branch of RAS Irkutsk State University

From a synthesis of data on volcanic evolution,movement of the lithosphere,and mantle velocities in the Baikal-Mongolian region,we propose a comprehensive model for deep dynamics of Asia that assumes an important role of the Gobi,Baikal,and North Transbaikal transition-layer melting *** layer was distorted by lower-mantle fluxes at the beginning of the latest geodynamic stage（*** the early late Cretaceous） due to avalanches of slab material that were stagnated beneath the closed fragments of the Solonker,Ural-Mongolian paleoceans and Mongol-Okhotsk Gulf of *** the latest geodynamic stage,Asia was involved in east-southeast movement,and the Pacific plate moved in the opposite direction with subduction under *** weakened upper mantle region of the Gobi melting anomaly provided a counterflow connected with rollback in the Japan Sea *** dynamics resulted in the formation of the Honshu-Korea flexure of the Pacific slab.A similar weakened upper mantle region of the North Transbaikal melting anomaly was associated with the formation of the Hokkaido-Amur flexure of the Pacific slab,formed due to progressive pull-down of the slab material into the transition layer in the direction of the Pacific plate and Asia *** early—middle Miocene structural reorganization of the mantle processes in Asia resulted in the development of upper mantle low-velocity domains associated with the development of rifts and *** propose that extension at the Baikal Rift was caused by deviator flowing mantle material,initiated under the moving lithosphere in the Baikal melting *** at the Hangay orogen was created by facilitation of the tectonic stress transfer from the Indo-Asian interaction zone due to the low-viscosity mantle in the Gobi melting anomaly.

关键词： Volcanism Geodynamics Cenozoic Asia Asthenosphere Lithosphere

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Sustainable Development Needs Connected and Integrated Sciences

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Engineering 2015年第1期1卷 4-5页

作者： irina Bokova UNESCO

I thank the Government of China and the Chinese Academy of Engineering for this initiative.I can hardly think of a better country to explore the power of engineering,science and *** a millennial history,China has give... 详细信息

关键词：可持续发展科学中国工程院整合连接中国政府社会发展成员国

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Combined effect of surface microgeometry and adhesion in normal and sliding contacts of elastic bodies

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Friction 2017年第3期5卷 339-350页

作者： irina GORYACHEVA Yulia MAKHOVSKAYA Institute for Problems in Mechanics of the Russian Academy of Sciences Pr.Vernadskogo 101-1 Moscow 119526 Russia

In this study,models are proposed to analyze the combined effect of surface microgeometry and adhesion on the load-distance dependence and energy dissipation in an approach-separation cycle,as well as on the formation and rupture of adhesive bridges during *** models are based on the Maugis-Dugdale approximation in normal and frictional (sliding and rolling) contacts of elastic bodies with regular surface *** the normal adhesive contact of surfaces with regular relief,an analytical solution,which takes into account the mutual effect of asperities,is *** contribution of adhesive hysteresis into the sliding and rolling friction forces is calculated for various values of nominal pressure,parameters of microgeometry,and adhesion.

关键词： adhesion roughness discrete contact rolling friction sliding friction

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