4,196 research outputs found
Gamma-radiation with E gamma 5 MeV detected from Seyfert galaxy 3C120 and region with 1" = 190 deg and b" = 20 deg
The observation of the Galaxy anticenter region in gamma-rays with E gamma = 5 / 100 MeV was made by gamma-telescope Natalya-1 in a balloon flight. The flight was performed at the ceiling 5.1 + or - 0.1 g/sq cm, magnetic cutoff being 17 GV. The description of the instrument and the analysis of the experiment conditions are given. The tracks of electron-positron pairs generated by gamma-quanta in the convertors were detected by wire spark chambers. The recorded events were classified manually by an operator using a graphic display into three classes: pairs, single and bad events. The arrival angle of gamma-quanta and their energy for selected gamma-ray events (pairs and singles) were determined through multiple scattering of pair components in the convertors. On the basis of the data obtained the celestial maps were made in gamma-rays for E sub gamma 5 MeV and E gamma 20 MeV energy ranges
Low-lying excitations and magnetization process of coupled tetrahedral systems
We investigate low-lying singlet and triplet excitations and the
magnetization process of quasi-1D spin systems composed of tetrahedral spin
clusters. For a class of such models, we found various exact low-lying
excitations; some of them are responsible for the first-order transition
between two different ground states formed by local singlets. Moreover, we find
that there are two different kinds of magnetization plateaus which are
separated by a first-order transition.Comment: To appear in Phys.Rev.B (Issue 01 August 2002). A short comment is
adde
MANAGING THE SURFACE PROPERTIES OF MATERIALS OF DISPLAY TECHNOLOGY BY MEANS OF TREATMENT IN ATMOSPHERIC DISCHARGE PLASMA
The results of research the surface of single-crystal silicon, glass, and stainless steel after processing in a plasma at atmospheric pressure are presented. It has been experimentally proved that after processing, the adhesive properties of the surface of materials are significantly improved.The results of research the surface of single-crystal silicon, glass, and stainless steel after processing in a plasma at atmospheric pressure are presented. It has been experimentally proved that after processing, the adhesive properties of the surface of materials are significantly improved
Crystal experiments on efficient beam extraction
Silicon crystal was channeling and extracting 70-GeV protons from the U-70
accelerator with efficiency of 85.3+-2.8% as measured for a beam of 10^12
protons directed towards crystals of 2 mm length in spills of 1-2 s duration.
The experimental data follow very well the prediction of Monte Carlo
simulations. This success is important to devise a more efficient use of the
U-70 accelerator in Protvino and provides a crucial support for implementation
of crystal-assisted collimation of gold ion beam in RHIC and slow extraction
from AGS onto E952, now in preparation at Brookhaven Nat'l Lab. Future
applications, spanning in the energy from sub-GeV (medical) to order of 1 GeV
(scraping in the SNS, extraction from COSY) to order of 1 TeV and beyond
(scraping in the Tevatron, LHC, VLHC), can benefit from these studies.Comment: 12pp. Presented at 19-th Intern. Conference on Atomic Collisions in
Solids (ICACS-19: Paris, July 29 - August 3, 2001
The Investigations Of Beam Extraction And Collimation At U-70 Proton Synchrotron Of IHEP By Using Short Silicon Crystals
The new results of using short (2-4mm) bent crystals for extraction and
collimation of proton beam at IHEP 70 Gev proton synchrotron are reported. A
broad range of energies from 6 to 65 GeV has been studied in the same crystal
collimation set-up. The efficiency of extraction more than 85% and intensity
more than 10E12 were obtained by using crystal with the length 2-mm and the
angle 1 mrad. The new regime of extraction is applied now at the accelerator to
deliver the beam for different experimental setups within the range of
intensity 10E7-10E12ppp.Comment: Presented at EPAC 2002 (Paris, June 3-7), 3p
RT-2 Detection of Quasi-Periodic Pulsations in the 2009 July 5 Solar Hard X-ray Flare
We present the results of an analysis of hard X-ray observations of the C2.7
solar flare detected by the RT-2 Experiment onboard the Coronas - Photon
satellite. We detect hard X-ray pulsations at periods of ~12 s and ~15 s. We
find a marginal evidence for a decrease in period with time. We have augmented
these results using the publicly available data from the RHESSI satellite. We
present a spectral analysis and measure the spectral parameters.Comment: 12 pages, 8 figures and 3 tables, accepted for publication in The
Astrophysical Journa
Dynamical structure factors of two-leg spin ladder systems
We investigate dynamical properties of two-leg spin ladder systems.
In a strong coupling region, an isolated mode appears in the lowest excited
states, while in a weak coupling region, an isolated mode is reduced and the
lowest excited states become a lower bound of the excitation continuum. We find
in the system with equal intrachain and interchain couplings that due to a
cyclic four-spin interaction, the distribution of the weights for the dynamical
structure factor and characteristics of the lowest excited states are strongly
influenced. The dynamical properties of two systems proposed for are also discussed.Comment: 5 pages, 6 figure
Suzaku measurement of Abell 2204's intracluster gas temperature profile out to 1800 kpc
Context: Measurements of intracluster gas temperatures out to large radii are
important for the use of clusters for precision cosmology and for studies of
cluster physics. Previous attempts to measure robust temperatures at cluster
virial radii failed. Aims: The goal of this work is to measure the temperature
profile of the very relaxed galaxy cluster Abell 2204 out to large radii,
possibly reaching the virial radius. Methods: Taking advantage of its low
particle background due to its low-Earth orbit, Suzaku data are used to measure
the outer temperature profile of Abell 2204. These data are combined with
Chandra and XMM-Newton data of the same cluster in order to make the connection
to the inner regions, unresolved by Suzaku, and to determine the smearing due
to Suzaku's PSF. Results: The temperature profile of Abell 2204 is determined
from 10 kpc to 1800 kpc, close to an estimate of r200 (the approximation to the
virial radius). The temperature rises steeply from below 4 keV in the very
center up to more than 8 keV in the intermediate range and then decreases again
to about 4 keV at the largest radii. Varying the measured particle background
normalization artificially by +-10 percent does not change the results
significantly. Predictions for outer temperature profiles based on hydrodynamic
simulations show good agreement. In particular, we find the observed
temperature profile to be slightly steeper but consistent with a drop of a
factor of 0.6 from 0.3 r200 to r200, as predicted by simulations. Conclusions:
Temperature measurements up to the virial radius seem feasible with Suzaku,
when a careful analysis of the different background components and the effects
of the PSF is performed. The result obtained here indicates that numerical
simulations capture the intracluster gas physics well in cluster outskirts.Comment: 7 pages; Astronomy and Astrophysics, accepted; additional systematic
effects have been quantified, results unchanged; also available at
http://www.reiprich.ne
Systems biology of cell behavior
Systems Biology approaches to drug discovery largely focus on the increasing understanding of intracellular and cellular circuits, by computational representation of a molecular system followed by parameter validation against experimental data. This chapter outlines a universal approach to systems biology that allows the linking of intracellular molecular machinery and cellular activity. This procedure is achieved by applying mathematical modeling to molecular modules of a cell in the light of systems biology techniques. © 2010 Springer Science+Business Media, LLC
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