76 research outputs found
Motivation and marriage choice in the context of research of matrimonal behavior of student youth
The article presents the results of research aimed at studying the features of the manifestation the matrimonial behavior of student youth. The analysis of the main marriage attitudes of this group was carried out on the basis of primary data obtained from a survey of students of the Belgorod State National Research Universit
Wind Accretion and State Transitions in Cygnus X-1
We present the results of a spectroscopic monitoring program (from 1998 to
2002) of the H-alpha emission strength in HDE 226868, the optical counterpart
of the black hole binary, Cyg X-1. The H-alpha profiles consist of (1) a P
Cygni component associated with the wind of the supergiant, (2) emission
components that attain high velocity at the conjunctions and that probably form
in enhanced outflows both towards and away from the black hole, and (3) an
emission component that moves in anti-phase with the supergiant's motion. We
argue that the third component forms in accreted gas near the black hole, and
the radial velocity curve of the emission is consistent with a mass ratio of
M_X / M_opt = 0.36 +/- 0.05. We find that there is a general anti-correlation
between the H-alpha emission strength and X-ray flux in the sense that when the
H-alpha emission is strong (W_\lambda < -0.5 Angstroms) the X-ray flux is
weaker and the spectrum harder. On the other hand, there is no correlation
between H-alpha emission strength and X-ray flux when H-alpha is weak. During
the low/hard X-ray state, the strong wind is fast and the accretion rate is
relatively low, while in the high/soft state the weaker, highly ionized wind
attains only a moderate velocity and the accretion rate increases. We argue
that the X-ray transitions from the normal low/hard to the rare high/soft state
are triggered by episodes of decreased mass loss rate in the supergiant donor
star.Comment: 45 pages, 16 figures, ApJ, in pres
On the Change of the Inner Boundary of an Optically Thick Accretion Disk around White Dwarfs Using the Dwarf Nova SS Cyg as an Example
We present the results of our studies of the aperiodic optical flux
variability for SS Cyg, an accreting binary systemwith a white dwarf. The main
set of observational data presented here was obtained with the ANDOR/iXon
DU-888 photometer mounted on the RTT-150 telescope, which allowed a record(for
CCD photometers) time resolution up to 8 ms to be achieved. The power spectra
of the source's flux variability have revealed that the aperiodic variability
contains information about the inner boundary of the optically thick flow in
the binary system. We show that the inner boundary of the optically thick
accretion disk comes close to the white dwarf surface at the maximum of the
source's bolometric light curve, i.e., at the peak of the instantaneous
accretion rate onto the white dwarf, while the optically thick accretion disk
is truncated at distances 8.5e9 cm ~10 R_{WD} in the low state. We suggest that
the location of the inner boundary of the accretion disk in the binary can be
traced by studying the parameters of the power spectra for accreting white
dwarfs. In particular, this allows the mass of the accreting object to be
estimated.Comment: 9 pages, 7 figures, Published in Astronomy Letter
Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VIII: The Eighth Year (2015-2016)
Continuing the project described by Kato et al. (2009, arXiv:0905.1757), we
collected times of superhump maxima for 128 SU UMa-type dwarf novae observed
mainly during the 2015-2016 season and characterized these objects. The data
have improved the distribution of orbital periods, the relation between the
orbital period and the variation of superhumps, the relation between period
variations and the rebrightening type in WZ Sge-type objects. Coupled with new
measurements of mass ratios using growing stages of superhumps, we now have a
clearer and statistically greatly improved evolutionary path near the terminal
stage of evolution of cataclysmic variables. Three objects (V452 Cas, KK Tel,
ASASSN-15cl) appear to have slowly growing superhumps, which is proposed to
reflect the slow growth of the 3:1 resonance near the stability border.
ASASSN-15sl, ASASSN-15ux, SDSS J074859.55+312512.6 and CRTS J200331.3-284941
are newly identified eclipsing SU UMa-type (or WZ Sge-type) dwarf novae.
ASASSN-15cy has a short (~0.050 d) superhump period and appears to belong to EI
Psc-type objects with compact secondaries having an evolved core. ASASSN-15gn,
ASASSN-15hn, ASASSN-15kh and ASASSN-16bu are candidate period bouncers with
superhump periods longer than 0.06 d. We have newly obtained superhump periods
for 79 objects and 13 orbital periods, including periods from early superhumps.
In order that the future observations will be more astrophysically beneficial
and rewarding to observers, we propose guidelines how to organize observations
of various superoutbursts.Comment: 123 pages, 162 figures, 119 tables, accepted for publication in PASJ
(including supplementary information
CVD-Enabled Graphene Manufacture and Technology.
Integrated manufacturing is arguably the most challenging task in the development of technology based on graphene and other 2D materials, particularly with regard to the industrial demand for “electronic-grade” large-area films. In order to control the structure and properties of these materials at the monolayer level, their nucleation, growth and interfacing needs to be understood to a level of unprecedented detail compared to existing thin film or bulk materials. Chemical vapor deposition (CVD) has emerged as the most versatile and promising technique to develop graphene and 2D material films into industrial device materials and this Perspective outlines recent progress, trends, and emerging CVD processing pathways. A key focus is the emerging understanding of the underlying growth mechanisms, in particular on the role of the required catalytic growth substrate, which brings together the latest progress in the fields of heterogeneous catalysis and classic crystal/thin-film growth.Funding from the ERC (Grant No. 279342, InSituNANO) and EPSRC (Grant No. EP/K016636/1, GRAPHTED) is acknowledged. R.S.W. acknowledges a research fellowship from St. John’s College, Cambridge.This is the final version of the article. It first appeared from ACS via http://dx.doi.org/10.1021/acs.jpclett.5b0105
Transfer-free electrical insulation of epitaxial graphene from its metal substrate
High-quality, large-area epitaxial graphene can be grown on metal surfaces
but its transport properties cannot be exploited because the electrical
conduction is dominated by the substrate. Here we insulate epitaxial graphene
on Ru(0001) by a step-wise intercalation of silicon and oxygen, and the
eventual formation of a SiO layer between the graphene and the metal. We
follow the reaction steps by x-ray photoemission spectroscopy and demonstrate
the electrical insulation using a nano-scale multipoint probe technique.Comment: Accepted for publication in Nano Letter
Correlations in the Electronic Structure of van der Waals NiPS3 Crystals An X ray Absorption and Resonant Photoelectron Spectroscopy Study
The electronic structure of high quality van der Waals NiPS3 crystals was studied using near edge X ray absorption spectroscopy NEXAFS and resonant photoelectron spectroscopy ResPES in combination with density functional theory DFT approach. The experimental spectroscopic methods, being element specific, allow one to discriminate between atomic contributions in the valence and conduction band density of states and give direct comparison with the results of DFT calculations. Analysis of the NEXAFS and ResPES data allows one to identify the NiPS3 material as a charge transfer insulator. Obtained spectroscopic and theoretical data are very important for the consideration of possible correlated electron phenomena in such transition metal layered materials, where the interplay between different degrees of freedom for electrons defines their electronic properties, allowing one to understand their optical and transport properties and to propose further possible applications in electronics, spintronics, and catalysi
Metamorphic evolution of mineral assemblages in the layered unit and its host rocks of the eastern part of the Pana Massif, Kola Peninsula
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