5,003 research outputs found
Models of infrared spectra of Sakurai's Object (V4334 Sgr) in 1997
Theoretical spectral energy distributions computed for a grid of
hydrogen-deficient and carbon-rich model atmospheres have been compared with
the observed infrared (1--2.5 m) spectra of V4334 Sgr (Sakurai's Object)
on 1997 April 21 and July 13. The comparison yields an effective temperature of
\Tef = 5500 200 K for the April date and \Tef = 5250 200 K for
July. The observed spectra are well fitted by Asplund et al. (1999) abundances,
except that the carbon abundance is higher by 0.3 dex. Hot dust produces
significant excess continuum at the long wavelength ends of the 1997 spectra.
\keywords{Stars: individual: V4334 Sgr (Sakurai's Object) -- Stars: AGB and
post-AGB evolution -- Stars: model atmospheres -- Stars: energy distributions
-- Stars: effective temperatures}Comment: 6 pages, 7 eps figs, accepted for A
CO-activator model for reconstructing Pt(100) surfaces: local microstructures and chemical turbulence
We present the results of the modelling of CO adsorption and catalytic CO
oxidation on inhomogeneous Pt(100) surfaces which contain structurally
different areas. These areas are formed during the CO-induced transition from a
reconstructed phase with hexagonal geometry of the overlayer to a bulk-like
(1x1) phase with square atomic arrangement. In the present approach, the
surface transition is explained in terms of nonequilibrium bistable behavior.
The bistable region is characterized by a coexistence of the hexagonal and
(1x1) phases and is terminated in a critical bifurcation point which is located
at (T_c ~680 K, p_CO ~10 Torr). Due to increasing fluctuations, the behavior at
high temperatures and pressures in the vicinity of this cusp point should be
qualitatively different from the hysteresis-type behavior which is typically
observed in the experiments under ultrahigh vacuum conditions. On the
inhomogeneous surface, we find a regime of nonuniform oscillations
characterized by random standing waves of adsorbate concentrations. The
resulting spatial deformations of wave fronts allow to gain deeper insight into
the nature of irregular oscillations on Pt(100) surface.Comment: 11 pages, 11 figures, to appear in Physical Review
The image of a writer in nobel lectures delivered by laureates in literature
Background. A growing interest in discursive nature of Nobel lectures resulted in a number of studies which emphasize their rhetorical force to influence public opinion and to popularize ideas in different spheres of human life. Analyzing Literature Laureates’ lectures, most researchers focus on linguistic means and the personality of the Nobelist himself/herself. However, characteristics of a writer proper have not been dealt with indepth. This article maintains our previous study, which indicates a close relationship between the content component of the Nobel lecture and the laureate’ outlook; the lecture itself can be regarded as a brief but extremely powerful expression of his/her human and professional qualities.
Purpose. The aim of this paper is to examine how literature laureates interpret the notion of a writer in their Nobel lectures and to identify main common themes in creating this collective image.
Methods. A method of linguistic description and observation, a descriptive method, and a contextual-interpretation method were employed to analyse the sample of 17 Nobel lectures.
Results. The outcomes of our study indicate that Nobel lectures are extremely powerful expression of prizewinners’ human and professional qualities. We have devised a set of five themes, namely the writer’s social duty, his/her destiny, literary background, tools, and literary outcome to describe the collective image of a writer. Within the framework of our research, literary background falls into two subthemes (literary heritage and a personal writing process); discussing the writer’s toolkit, we focus on language and words.
Discussion. Our findings show that laureates develop the concept “writer” to varying degrees but all of them stress a direct interconnection between an active social position and the writer’s destiny. Further research can involve the in-depth study of a definite Nobel lecture in terms of the compositional structure and employed linguistic means
Нобелівська лекція як віддзеркалення світогляду лауреата
Статтю присвячено дослідженню змістової складової такого специфічного мовленнєвого жанру як Нобелівська лекція. Увагу зосереджено на проблемно-тематичних характеристиках англомовних лекцій, які були прочитані лауреатами в галузі літератури. Проаналізовано чинники, що впливають на зміст лекції. Встановлено взаємозв’язок між темою доповіді та офіційним обґрунтуванням нагороди членами Шведської академії
Ultracool dwarfs
We present results of modeling of spectra of M-, L-, T-dwarfs. Theoretical
spectra are fitted to observed spectra to study the main parameters of the
low-mass objects beyond the bottom of Main Sequence. Application of ``lithium''
and ``deuterium'' tests for assessment of ultra-cool dwarfs are discussed.Comment: Talk for MAO2004 Meeting (Kyiv, July 15-17, 2004), see more details
on http://www.mao.kiev.ua/mao-2004/public.htm, 6 pages, 3fig
12C/13C in atmospheres of red giants and peculiar stars
We determine the carbon isotopic ratios in the atmospheres of some evolved
stars in both globular clusters and the disk of our Galaxy. Analysis of 12CO
and 13CO bands at 2.3 micron was carried out using fits to observed spectra of
red giants and Sakurai's object (V4334 Sgr). The dependence of theoretical
spectra on the various input parameters was studied in detail. The computation
of model atmospheres and a detailed abundance analysis was performed in a
self-consistent fashion. A special procedure for determining the best fits to
observed spectra was used. We show, that globular cluster giants with [Fe/H] <
-1.3 have a low 12C/13C = 4 +/- 1 abundance ration. In the spectra of Sakurai's
object (V4334 Sgr) taken between 1997-98, the 2.3 micron spectral region is
veiled by hot dust emission. By fitting UKIRT spectra we determined 12C/13C = 4
+/- 1 for the July, 1998 spectrum. CO bands in the spectra of ultracool dwarfs
are modelled as well.Comment: Poster for IAU Symposium No. 228, "From Lithium to Uranium: Elemental
Tracers of Early Cosmic Evolution", V. Hill, P. Francois & F. Primas, eds.
(2005); 2 pages, ppt is available on
ftp://ftp.mao.kiev.ua/%2f/pub/users/yp/12C13C_for_IAU228.pp
Lithium in LP 944-20
The definitive version is available at www.blackwell-synergy.com. Copyright Blackwell Publishing DOI :10.1111/j.1365-2966.2007.12182.xPeer reviewe
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