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Search Results: 1 - 10 of 582980 matches for " D. A. Egorov "
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Polycyclic aromatic hydrocarbons in the dwarf galaxy IC 10
D. S. Wiebe,O. V. Egorov,T. A. Lozinskaya
Physics , 2011, DOI: 10.1134/S1063772911070080
Abstract: Infrared observations from the Spitzer Space Telescope archive are used to study the dust component of the interstellar medium in the IC~10 irregular galaxy. Dust distribution in the galaxy is compared to the distributions of H$\alpha$ and [SII] emission, neutral hydrogen and CO clouds, and ionizing radiation sources. The distribution of polycyclic aromatic hydrocarbons (PAH) in the galaxy is shown to be highly non-uniform with the mass fraction of these particles in the total dust mass reaching 4%. PAHs tend to avoid bright HII regions and correlate well with atomic and molecular gas. This pattern suggests that PAHs form in the dense interstellar gas. We propose that the significant decrease of the PAH abundance at low metallicity is observed not only globally (at the level of entire galaxies), but also locally (at least, at the level of individual HII regions). We compare the distribution of the PAH mass fraction to the distribution of high-velocity features, that we have detected earlier in wings of H$\alpha$ and SII lines, over the entire available galaxy area. No conclusive evidence for shock destruction of PAHs in the IC~10 galaxy could be found.
Dark polariton-solitons in semiconductor microcavities
A. V. Yulin,O. A. Egorov,F. Lederer,D. V. Skryabin
Physics , 2008, DOI: 10.1103/PhysRevA.78.061801
Abstract: We report the existence, symmetry breaking and other instabilities of dark polariton-solitons in semiconductor microcavities operating in the strong coupling regime. These half-light half-matter solitons are potential candidates for applications in all-optical signal processing. Their excitation time and required pump powers are a few orders of magnitude less than those of their weakly coupled light-only counterparts.
Bright cavity polariton solitons
O. A. Egorov,D. V. Skryabin,A. V. Yulin,F. Lederer
Physics , 2009, DOI: 10.1103/PhysRevLett.102.153904
Abstract: The lower branch of the dispersion relation of exciton polaritons in semiconductor microcavities, operating in the strong-coupling regime, contains sections of both positive and negative curvature along one spatial direction. We show that this leads to the existence of stable one-dimensional bright microcavity solitons supported by the repulsive polariton nonlinearity. To achieve localization along the second transverse direction we propose to create a special soliton waveguide by changing the cavity detuning and hence the boundary of the soliton existence in such a way that the solitons are allowed only within the stripe of the desired width.
Gas Emission Spectrum in the Irr Galaxy IC 10
T. A. Lozinskaya,O. V. Egorov,A. V. Moiseev,D. V. Bizyaev
Physics , 2009, DOI: 10.1134/S1063773709110024
Abstract: Spectroscopic long-slit observations of the dwarf Irr galaxy IC 10 were conducted at the 6-m Special Astrophysical Observatory telescope with the SCORPIO focal reducer. The ionized-gas emission spectra in the regions of intense current star formation were obtained for a large number of regions in IC 10. The relative abundances of oxygen, N+, and S+ in about twenty HII regions and in the synchrotron superbubble were estimated. We found that the galaxy-averaged oxygen abundance is 12 + log(O/H) = 8.17 +- 0.35 and the metallicity is Z = 0.18 +- 0.14 Z_sun. Our abundances estimated from the strong emission lines are found to be more reliable than those obtained by comparing diagnostic diagrams with photoionization models.
Evaluation of Polarization Mode Dispersion and Chromatic Dispersion using Quantum Interferometry
A. Fraine,D. S. Simon,O. Minaeva,R. Egorov,A. V. Sergienko
Physics , 2011,
Abstract: The use of quantum correlations between photons to measure polarization mode dispersion (PMD) and chromatic dispersion is investigated. Two types of apparatus are discussed which use coincidence counting of entangled photon pairs to allow sub-femtosecond resolution for measurement of both PMD and chromatic dispersion, as well as separation of even-order and odd-order chromatic effects in the PMD. Group delays can be measured with a resolution of order 0.1 fs, whereas attosecond resolution can be achieved for phase delays.
First Results of ACH Cardioplegic Solution Clinical Application in Newborns and Infants under One Year of Age  [PDF]
L. A. Bockeria, A. A. Boldyrev, O. I. Kulaga, G. A. Blejyants, D. N. Egorov, A. E. Popov, K. V. Mumladze, I. F. Egorova, T. V. Artuhina, N. V. Kalaeva, R. R. Movsesian
World Journal of Cardiovascular Diseases (WJCD) , 2013, DOI: 10.4236/wjcd.2013.35A006
Abstract: Study objective involved comparison of two cardioplegic solutions: HTK-solution possessing high buffer capacity and a new ACH-solution with aminoacid buffer. Results revealed high cardioprotective efficiency during surgical repair of complex congenital heart disease both in the group that had received Custodiol and in the group that had received ACH-solution. Clinical and morphological parameters demonstrate high level of myocardial protection from intraoperative ischemia for single usage of ACH-solution during cardioplegic ischemia under 60 minutes in duration.
Dust Evolution in the Dwarf Galaxy Holmberg II
D. S. Wiebe,M. S. Khramtsova,O. V. Egorov,T. A. Lozinskaya
Physics , 2014, DOI: 10.1134/S1063773714050065
Abstract: A detailed photometric study of star-forming regions (SFRs) in the galaxy Holmberg II has been carried out using archival observational data from the far infrared to ultraviolet obtained with the GALEX, Spitzer, and Herschel telescopes. Spectroscopic observations with the 6-m telescope of Special Astrophysical Observatory of the Russian Academy of Sciences are used to estimate ages and metallicities of SFRs. For the first time, the ages of SFRs have been related to their emission parameters in a wide spectral range and with the physical parameters determined by fitting the observed spectra. It is shown that fluxes at 8 and 24 micron characterizing the emission of polycyclic aromatic hydrocarbons (PAHs) and hot dust grains decrease with age, but their ratio increases. This implies that the relative PAH contribution to the total infrared flux increases with age. It is suggested that the detected increase in the ratio of the fluxes at 8 and 24 micron is related to the growth in the PAH mass due to destruction of larger grains.
Optical and infrared emission of H II complexes as a clue to the PAH life cycle
M. S. Khramtsova,D. S. Wiebe,T. A. Lozinskaya,O. V. Egorov
Physics , 2014, DOI: 10.1093/mnras/stu1482
Abstract: We present an analysis of optical spectroscopy and infrared aperture photometry of more than 100 H II complexes in nine galaxies. Spectra obtained with the 6-m telescope of SAO RAS are used along with archival data from Spitzer and several ground-based telescopes to infer a strength of polycyclic aromatic hydrocarbon (PAH) emission, age, properties of the UV radiation field, and metallicity of studied H II complexes. Physical properties (age, radiation field parameters, metallicity) are related to the $F_{8}/F_{24}$ ratio used as a proxy for the PAH abundance in order to reveal factors that may influence the PAH evolution in H II complexes. The well-known correlation between the $F_{8}/F_{24}$ ratio and metallicity is confirmed in the studied complexes. The infrared flux ratio also correlates with the [O III]$\lambda 5007/\mathrm{H\beta}$ ratio which is often considered as an indicator of the radiation field hardness, but this correlation seems to be a mere reflection of a correlation between [O III]$\lambda 5007/\mathrm{H\beta}$ and metallicity. In separate metallicity bins, the $F_{8}/F_{24}$ ratio is found to correlate with an age of an H II complex, which is estimated from the equivalent width of $\mathrm{H}\beta$ line. The correlation is positive for low metallicity complexes and negative for high metallicity complexes. Analysing various mechanisms of PAH formation and destruction in the context of found correlations, we suggest that PAH abundance is likely altered by the UV radiation within H II complexes, but this is not necessarily due to their destruction. If PAHs can also form in H II complexes due to some processes like aromatisation, photodestruction, shattering and sputtering of very small grains, the net $F_{8}/F_{24}$ ratio is determined by a balance between all these processes that can be different at different metallicities.
Quantum noise in three-dimensional BEC interferometry
B. Opanchuk,M. Egorov,S. Hoffmann,A. Sidorov,P. D. Drummond
Physics , 2011, DOI: 10.1209/0295-5075/97/50003
Abstract: We develop a theory of quantum fluctuations and squeezing in a three-dimensional Bose-Einstein condensate atom interferometer with nonlinear losses. We use stochastic equations in a truncated Wigner representation to treat quantum noise. Our approach includes the multi-mode spatial evolution of spinor components and describes the many-body dynamics of a mesoscopic quantum system.
The Influence of Feed Intake and Conditioned Reflex on Exocrine Pancreatic Function in Broiler Chicks  [PDF]
Vladimir G. Vertiprakhov, Ivan A. Egorov
Open Journal of Animal Sciences (OJAS) , 2016, DOI: 10.4236/ojas.2016.64034
Abstract: The data of an experimental study of the influence of feeding and the conditional stimulus on digestive function in birds is presented. It is stated that feed consumption is a powerful stimulator of pancreatic secretion in broiler chicks. The secretory response of the pancreas was the highest in the morning when secretion of pancreatic juice was 1.8 times higher, amylase activity 3.2 times, proteases activity 3.3 times, lipase activity 2.1 times higher than before feeding (basal levels). The regulation of pancreatic activity is known to be complex-reflex with conditioned-reflex component being very important since it provides 25% higher juice secretion and 42% - 74% higher enzyme secretion compared to the basal levels during few minutes after the conditional signal.
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