4,110 research outputs found
Properties of discrete breathers in graphane from ab initio simulations
A density functional theory (DFT) study of the discrete breathers (DBs) in
graphane (fully hydrogenated graphene) was performed. To the best of our
knowledge, this is the first demonstration of the existence of DBs in a
crystalline body from the first-principle simulations. It is found that the DB
is a robust, highly localized vibrational mode with one hydrogen atom
oscillating with a large amplitude along the direction normal to the graphane
plane with all neighboring atoms having much smaller vibration amplitudes. DB
frequency decreases with increase in its amplitude, and it can take any value
within the phonon gap and can even enter the low-frequency phonon band. The
concept of DB is then used to propose an explanation to the recent experimental
results on the nontrivial kinetics of graphane dehydrogenation at elevated
temperatures.Comment: 20.07.14 Submitted to PhysRev
Oncology disease in patients with acute myocardial infarction with nonobstructive coronary atherosclerosis
The aim of this study was to evaluate the cancer incidence among patients with myocardia
Radio emission from satellite-Jupiter interactions (especially Ganymede)
Analyzing a database of 26 years of observations of Jupiter from the
Nan\c{c}ay Decameter Array, we study the occurrence of Io-independent emissions
as a function of the orbital phase of the other Galilean satellites and
Amalthea. We identify unambiguously the emissions induced by Ganymede and
characterize their intervals of occurrence in CML and Ganymede phase and
longitude. We also find hints of emissions induced by Europa and, surprisingly,
by Amalthea. The signature of Callisto-induced emissions is more tenuous.Comment: 14 pages, 7 figures, in "Planetary Radio Emissions VIII", G. Fischer,
G. Mann, M. Panchenko and P. Zarka eds., Austrian Acad. Sci. Press, Vienna,
in press, 201
Intraobserver reproducibility of parameters of standard and 2D speckle tracking echocardiography, dynamics of global longitudinal strain I in patients with acute primary anterior STEMI
The aim of this study was to assess the intraobserver reproducibility of parameters of standard and 2 dimensional speckle tracking echocardiography, dynamics of global longitudinal strain in patients with acute primary anterior STEMI. The study included 24 patients, mean age 58.46±10.2. Echocardiography with 2D speckle tracking imaging was performed on the 1st (T1), 7th (T2), 14th days (T3) after STEMI («Vivid E9»). Analysis of echocardiographic images was performed offline at the different periods by the two independent observers (EchoPac) – experienced and inexperienced. In order to assess the agreement between standard and 2D speckle tracking echocardiography, a correlation analysis (Pearson correlation, Spearman’s rank correlation coefficient) and Bland-Altman analysis were undertaken. The 23 patients had urgent reperfusion therapy, 6 patients underwent primary PCI, 16 patients – PCI after successful fibrinolysis (68%). GLS and WMSI had the best intraobsever reproducibility. Dynamics of EDV LV, ESV LV, EF LV was without significant differences. Nevertheless, it was found positive dynamic of GLS: – 12.65±3.53 (T1), -13.61±3.81 (T2), –14.27±4.1 (T3), p<0.05. GLS reduced 11.35% (p=0.0048) from T1 to T3. The best intraobserver reproducibility of parameters of 2 D speckle-tracking and standard echocardiography was revealed in GLS and WMSI. The modern management of STEMI patients limits adverse postinfarction remodeling and preserves of global left ventricular contractility detected by the EF LV. However, GLS had the positive dynamics and improved to the 14th day
Stability of Nonlinear Normal Modes in the FPU- Chain in the Thermodynamic Limit
All possible symmetry-determined nonlinear normal modes (also called by
simple periodic orbits, one-mode solutions etc.) in both hard and soft
Fermi-Pasta-Ulam- chains are discussed. A general method for studying
their stability in the thermodynamic limit, as well as its application for each
of the above nonlinear normal modes are presented
The "Horizon-T" Experiment: Extensive Air Showers Detection
Horizon-T is an innovative detector system constructed to study Extensive Air
Showers (EAS) in the energy range above 10^16 eV coming from a wide range of
zenith angles (0 - 85 degrees). The system is located at Tien Shan
high-altitude Science Station of Lebedev Physical Institute of the Russian
Academy of Sciences at approximately 3340 meters above the sea level. It
consists of eight charged particle detection points separated by the distance
up to one kilometer as well as optical detector subsystem to view the
Vavilov-Cerenkov light from the EAS. The time resolution of charged particles
and Vavilov-Cerenkov light photons passage of the detector system is a few ns.
This level of resolution allows conducting research of atmospheric development
of individual EAS.Comment: Initial technical note for Horizon-T experiment, updated with recent
detector upgrades, 11/2016. Updated 12/2017 with minor edits. Large upgrade
will be in another articl
Oxidation of n-С5-С8 hydrocarbons and cyclohexane in a reactor with barrier discharge. P. 2. Simulating cyclohexane oxidation reaction
Numerical model of hydrocarbon oxidation kinetics in a reactor with barrier discharge has been proposed by the example of cyclohexane oxidation reaction. The results of calculations with the use of barrier discharge surface model showed that electron energy and other discharge characteristics in pure oxygen and in the mixture of oxygen with cyclohexane vapors slightly differ that allowed using a simplified model of homogeneous discharge for simulating cyclohexane oxidation reaction. The results of calculation showed good fit with the experimental dat
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