102 research outputs found
Application of synchrotron radiation to study the surface atomic structure of 2D materials
In this paper, the current state of X-ray photoelectron diffraction and holography methods are considered. A brief overview of surface research methods is given. The photoelectron diffraction method is attractive for use because of its sensitivity to the chemical environment, as well as its large depth of analysis (units of nanometers). The paper presents the application of methods for studying the atomic structure of bismuth chalcogenides Bi2X3 (X: Se,Te). The results of the holography were verified by theoretical modeling of diffraction patterns using the EDAC algorithm. © 2020 American Institute of Physics Inc. All rights reserved.The reported study was funded by RFBR, project number 19-29-12061 and was carried out within the state assignment of Ministry of Science and Higher Education of the Russian Federation (theme “Spin” No. АААА-А18-118020290104-2). L.V.Yashina acknowledges the support of her experimental work by RSF, grant 19-42-06303. We thank HZB for the allocation of synchrotron radiation beamtime
Galactic Rotation Parameters from Data on Open Star Clusters
Currently available data on the field of velocities Vr, Vl, Vb for open star
clusters are used to perform a kinematic analysis of various samples that
differ by heliocentric distance, age, and membership in individual structures
(the Orion, Carina--Sagittarius, and Perseus arms). Based on 375 clusters
located within 5 kpc of the Sun with ages up to 1 Gyr, we have determined the
Galactic rotation parameters
Wo =-26.0+-0.3 km/s/kpc,
W'o = 4.18+-0.17 km/s/kpc^2,
W''o=-0.45+-0.06 km/s/kpc^3, the system contraction parameter K = -2.4+-0.1
km/s/kpc, and the parameters of the kinematic center Ro =7.4+-0.3 kpc and lo =
0+-1 degrees. The Galactocentric distance Ro in the model used has been found
to depend significantly on the sample age. Thus, for example, it is 9.5+-0.7
kpc and 5.6+-0.3 kpc for the samples of young (50 Myr)
clusters, respectively. Our study of the kinematics of young open star clusters
in various spiral arms has shown that the kinematic parameters are similar to
the parameters obtained from the entire sample for the Carina-Sagittarius and
Perseus arms and differ significantly from them for the Orion arm. The
contraction effect is shown to be typical of star clusters with various ages.
It is most pronounced for clusters with a mean age of 100 Myr, with the
contraction velocity being Kr = -4.3+-1.0 km/s.Comment: 14 pages, 4 figures, 2 table
Asymmetrical current generator operating modes in battery charging
This paper presents the investigation of the different operating modes of the asymmetrical quasi-sinusoidal output current inductive-switch generator. The purpose of investigation is to find the most effective operation mode where an acceptable output current quality is combined with relatively small dynamic losses in switches. Depending on the algorithm of the generator switches, there are four operating modes. The calculations describing the generator operating principle were obtained for each operating mode
IMPLEMENTATION OF THE EDAC ALGORITHM FOR CALCULATING PHOTOELECTRON DIFFRACTION IN MATLAB
This paper discusses the implementation of the EDAC algorithm in the MATLAB devel-opment environment. This allows you to use the features of MatLab, as well as further sharing in the open source format.Работа выполнена при поддержке РФФИ № 19-29-12061 и проводилось в рамках государственного задания Министерства науки и высшего образования РФ (тема «Спин» № AAAA-A18-118020290104-2). Л.В. Яшина благодарит РНФ за поддержку ее экспериментальной работы, грант 19-42-06303
Kinematic Peculiarities of Gould Belt Stars
We analyzed the space velocities of Gould Belt stars younger than 125 Myr
located at heliocentric distances <650 pc. We determined the rotation and
expansion parameters of the Gould Belt by assuming the existence of a single
kinematic center whose direction was found to be the following:
and pc. The linear velocities reach their
maximum at a distance of pc from the center and are -6 km s
for the rotation (whose direction coincides with the Galactic rotation) and +4
km s for the expansion. The stellar rotation model used here is shown to
give a more faithful description of the observed velocity field than the linear
model based on the Oort constants and . We present evidence that the
young clusters Pic, Tuc/HorA, and TWA belong to the Gould Belt
structure.Comment: 17 pages, 5 figure
Transcriptome 3′end organization by PCF11 links alternative polyadenylation to formation and neuronal differentiation of neuroblastoma
In gene regulation, diversification at the transcriptome 3′end is linked to differentiation and dedifferentiation. Here, the authors discover extensive transcriptome 3′end-alterations in neuroblastoma, regulated by PCF11, and provide an interactive data repository of transcriptome-wide alternative polyadenylation
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