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Earthquake risk assessment for Istanbul metropolitan area

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Earthquake Engineering and Engineering Vibration 2003年第1期2卷 1-24页

作者： M.Erdik N.Aydinoglu Y.Fahjan K.Sesetyan M.Demircioglu B.Siyahi E.Durukal C.Ozbey Y.Biro H.Akman O.Yuzugullu Bo■azici university Kandilli Observatory and Earthquake Research InstituteDepartment of Earthquake EngineeringIstanbulTurkey Professor Doctor Bo■azici university Kandilli Observatory and Earthquake Research InstituteDepartment of Earthquake EngineeringIstanbulTurkey Assistant Professor Bo■azici university Kandilli Observatory and Earthquake Research InstituteDepartment of Earthquake EngineeringIstanbulTurkey Research Assistant Bo■azici university Kandilli Observatory and Earthquake Research InstituteDepartment of Earthquake EngineeringIstanbulTurkey Associate Professor

The impact of earthquakes in urban centers prone to disastrous earthquakes necessitates the analysis of associ- ated risk for rational formulation of contingency plans and mitigation *** urban centers,the seismic risk is best quantified and portrayed through the preparation of'Earthquake Damage and Loss Scenarios.'The components of such scenarios are the assessment of the hazard,inventories and the vulnerabilities of elements at *** the development of the earthquake risk scenario in Istanbul,two independent approaches,one based on intensities and the second on spectral displacements,are *** paper will present the important features of a comprehensive study,highlight the method- ology,discuss the results and provide insights to future developments.

关键词： earthquake risk assessment metropolitan area intensity spectral displacement earthquake damage loss scenario

Light curve solutions of six eclipsing binaries at the lower limit of periods for W UMa stars

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Research in Astronomy and Astrophysics 2015年第9期15卷 1493-1503页

作者： Diana P.Kjurkchieva Dinko P.Dimitrov Sunay I.Ibryamov Department of Physics Shumen University institute of Astronomy and National Astronomical observatory Bulgarian Academy of Sciences

Photometric observations are presented in V and I bands of six eclipsing binaries at the lower limit of the orbital periods for W UMa stars. Three of them are newly discovered eclipsing systems. The light curve solutions reveal that all shortperiod targets are contact or overcontact binaries and six new binaries are added to the family of short-period systems with estimated parameters. Four binaries have com- ponents that are equal in size and a mass ratio near 1. The phase variability shown by the V-I colors of all targets may be explained by lower temperatures on their back surfaces than those on their side surfaces. Five systems exhibit the O＇Connell effect that can be modeled by cool spots on the side surfaces of their primary components. The light curves of V1067 Her in 2011 and 2012 are fitted by diametrically opposite spots. Applying the criteria for subdivision of W UMa stars to our targets leads to ambiguous results.

关键词： methods: data analysis -- catalogs -- stars: fundamental parameters-- stars: binaries: eclipsing: individual (1SWASP J173828.46+111150.2 1SWASPJ174310.98+432709.6 ≡ V1067 Her NSVS 11534299 NSVS 10971359 NSVS11234970 NSVS 11504202)

RELATIONSHIPS BETWEEN PRECEDING PACIFIC SEA SURFACE TEMPERATURES AND SUBTROPICAL HIGH INDEXES OF MAIN RAINING SEASONS

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Journal of Tropical Meteorology 2009年第1期15卷 97-101页

作者：姚愚严华生 Kunming Meteorological observatory institute of Resource and Earth Science Yunnan University

With correlation analysis and factor analysis methods, the effects of preceding Pacific SSTs on subtropical high indexes of main raining seasons are discussed. The results of correlation analysis show that the effects of SSTs on five subtropical high indexes differ in seasons and regions. The variation of SSTs mostly affects the area and intensity indexes of the subtropical high, followed by the western ridge index, and the effect on the ridge line index is more remarkable than on the north boundary index. The results of factor analysis reveals that the first common factor of SST of each season reflected mainly the inverse relation of SSTs variation between the central and eastern part of equatorial Pacific and the western Pacific, which correlates better with the subtropical high indexes in the main raining seasons than other common factors of SST. The analysis of interdecadal variation indicated that the variation of SSTs was conducive to the emergence of the La Ni?a event before the end of 1970s, such that in the summer the subtropical high is likely to be weaker and smaller and located eastward and northward. After the 1980s, the opposite characteristics prevailed.

关键词： climatology relationship correlation analysis factor analysis sea surface temperature subtropical high index

Detection of large color variation in the potentially hazardous asteroid(297274) 1996 SK

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Research in Astronomy and Astrophysics 2014年第3期14卷 311-318页

作者： Chien-Hsien Lin Wing-Huen Ip Zhong-Yi Lin Fumi Yoshida Yu-Chi Cheng Space Science institute Macao University of Science and Technology institute of Astronomy National Central University National Astronomical observatory Osawa MitakaTokyo

Low-inclination near-earth asteroid （NEA）（297274） 1996 SK, which isalso classified as a potentially hazardous asteroid, has a highly eccentric orbit. Itwas studied by multi-wavelength photometry within the framework of an NEA colorsurvey at Lulin observatory. Here, we report the finding of large color variationacross the surface of （297274） 1996 SK within one asteroidal rotation period of4.656 ± 0.122 hours and classify it as an S-type asteroid according to its averagecolors ofB - V = 0.767 ± 0.033, V - R = 0.482 ± 0.021, V - I = 0.801 ± 0.025and the corresponding relative reflectance spectrum. These results might be indica-tive of differential space weathering or compositional inhomogeneity in the surfacematerials.

关键词： minor planets, asteroids: individual: PHA (297274) techniques: photometric

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Science China(Technological Sciences) 2014年第12期57卷 2418-2425页

作者： WANG De Dong YUAN Zhi Gang DENG Xiao Hua ZHOU Meng HUANG Shi Yong LI Ming LI Hui Min LI Hai Meng RAITA Tero PANG Ye School of Electronic Information Wuhan University institute of Space Science and Technology Nanchang University Sodankyl Geophysical observatory University of Oulu

With coordinated observations of the NOAA 15 satellite and OUL magnetometer station in Finland, we report that the elec- tromagnetic ion cyclotron （EMIC） waves which were stimulated by the compression of the magnetosphere drive relativistic electron precipitation in geoquiescence on 1 Jan 2007. After an enhancement of solar wind dynamic pressure （SWDP）, a day- side Pcl pulsation was observed by the OUL station. Such a Pcl pulsation is caused by an EMIC wave which propagates from the generation source to lower altitudes. Simultaneously, the NOAA 15 satellite registered an enhancement of precipitating electron count rates with energies 〉3 MeV within the anisotropic zone of protons. This phenomenon is coincident with the quasi-linear theoretical calculation presented in this paper. Our observations suggest that after a positive impulse of solar wind, the compression-related EMIC waves can drive relativistic electrons precipitation and play a pivotal role in the dynamic of ra- diation belts.

关键词： radiation belt Solar wind dynamic pressure (SWDP) electromagnetic ion cyclotron (EMIC) waves precipitation rela-tivistic electron

A Note on the Mixing Length Theory and Massive Star Evolution

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Chinese Journal of Astronomy and Astrophysics 2001年第1期1卷 50-56页

作者： Li-Cai Deng and Da-Run Xiong ( Beijing Astronomical observatory, Chinese Academy of Sciences, Beijing 100012 Purple Mountain observatory, Chinese Academy of Sciences, Nanjing210008 National Astronomical Observatories, Chinese Academy of Sciences, Beij CAS-Peking university Joint Beijing astrophysical Center Beijing 100871

In this paper, we investigate the problem of supersonic convection caused by the application of the usual Mixing Length Theory (MLT), and give a modification to the original expression of the MLT. In the case of the usual MLT, a zone of supersonic convection exists when the stellar model goes into yellow-red supergiant phase. When the modification is applied, the models of late type supergiants possess shallower convective envelopes for a given temperature compared with the normal formalism of the MLT. Therefore the stellar models made with our new formalism move to lower effective temperature by 100-400 K depending on the luminosity of the star. Such a modification does not affect the convective envelope structure of lower luminosity late type stars, as both expressions of the MLT give the same result. In these stars.

关键词： convection - stars: supergiants - stars: massive stars - stars: evolution

Charge density fluctuation of low frequency in a dusty plasma

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Science China Mathematics 1997年第2期40卷 206-213页

作者：李芳吕保维 O.Havnes institute of Electronics Chinese Academy of SciencesBeijing 100080China Auroral observatory University of TromsoNorway

The charge density fluctuation of low frequency in a dusty plasma, which is derived from the longitudinal dielectric permittivity of the dusty plasma, has been studied by kinetic theory. The results show that the P value, which describes the relative charge density on the dust in the plasma, and the charging frequency of a dust particle Ωc, which describes the ratio of charge changing of the dust particles, determine the character of the charge density fluctuation of low frequency. For a dusty plasma of P>1, when the frequency Ωc, is much larger than wd there are weaker fluctuations with a wide spectrum. The results have been applied to the ionosphere and the range of radius and density of dust particles is found, where a strong charge density fluctuation of low frequency should exist.

关键词： dusty plasma charge density fluctuation charging frequency of a dust particle

Dynamics of neutrino-driven winds:inclusion of accurate weak interaction rates in strong magnetic fields

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Research in Astronomy and Astrophysics 2013年第2期13卷 207-214页

作者： Men-Quan Liu Zhong-Xiang Wang Shanghai Astronomical observatory Chinese Academy of Sciences institute of Theoretical Physics China West Normal University

Solving Newtonian steady-state wind equations while considering the ac- curate weak interaction rates and magnetic fields （MFs） of young neutron stars, we study the dynamics and nucleosynthesis of neutrino-driven winds （NDWs） from proto neutron stars （PNSs）. For a typical 1.4 Mo PNS model, we find that the nucleosyn- thesis products are closely related to the luminosity of neutrinos and anti-neutrinos. The lower the luminosity is, the larger is the effect on the NDWs caused by weak in- teractions and MFs. At a high anti-neutrino luminosity of typically 8 × 1051 erg s-1, neutrinos and anti-neutrinos dominate the processes in an NDW and the MFs hardly change the wind＇s properties. But at a low anti-neutrino luminosity of 1051 erg s-1 at the late stage of an NDW the mass of the product and process of nucleosynthesis are changed significantly in strong MFs. Therefore, in most of the models considered for the NDWs from PNSs, based on our calculations, the influences of MFs and the net weak interactions on the nucleosynthesis are not significant.

关键词： nuclear reactions, nucleosynthesis, abundances -- hydrodynamics --stars neutrons

Solutions to Forced and Unforced Lin–Reissner–Tsien Equations for Transonic Gas Flows on Various Length Scales

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Communications in Theoretical Physics 2017年第3期67卷 309-316页

作者： Kyle A.Theaker Robert A.Van Gorder Department of Mathematics University of Central Florida Mathematical institute University of Oxford Andrew Wiles Building Radcliffe Observatory Quarter

The Lin–Reissner–Tsien equation is useful for studying transonic gas flows, and has appeared in both forced and unforced forms in the literature. Defining arbitrary spatial scalings, we are able to obtain a family of exact similarity solutions depending on one free parameter in addition to the model parameter holding the scalings. Numerical solutions compare favorably with the exact solutions in regions where the exact solutions are valid. Mixed wave-similarity solutions, which describe wave propagation in one variable and self-similar scaling of the entire solution, are also given,and we show that such solutions can only exist when the wave propagation is sufficiently slow. We also extend the Lin–Reissner–Tsien equation to have a forcing term, as such equations have entered the physics literature recently. We obtain both wave and self-similar solutions for the forced equations, and we are able to give conditions under which the force function allows for exact solutions. We then demonstrate how to obtain these exact solutions in both the traveling wave and self-similar cases. There results constitute new and potentially physically interesting exact solutions of the Lin–Reissner–Tsien equation and in particular suggest that the forced Lin–Reissner–Tsien equation warrants further study.

关键词： Lin-Reissner-Tsien equation similarity transform nonlinear waves exact solutions