203 research outputs found
Particles and strings in a (2+1)-D integrable quantum model
We give a review of some recent work on generalization of the Bethe ansatz in
the case of -dimensional models of quantum field theory. As such a model,
we consider one associated with the tetrahedron equation, i.e. the
-dimensional generalization of the famous Yang--Baxter equation. We
construct some eigenstates of the transfer matrix of that model. There arise,
together with states composed of point-like particles analogous to those in the
usual -dimensional Bethe ansatz, new string-like states and
string-particle hybrids
On exact solution of a classical 3D integrable model
We investigate some classical evolution model in the discrete 2+1 space-time.
A map, giving an one-step time evolution, may be derived as the compatibility
condition for some systems of linear equations for a set of auxiliary linear
variables. Dynamical variables for the evolution model are the coefficients of
these systems of linear equations. Determinant of any system of linear
equations is a polynomial of two numerical quasimomenta of the auxiliary linear
variables. For one, this determinant is the generating functions of all
integrals of motion for the evolution, and on the other hand it defines a high
genus algebraic curve. The dependence of the dynamical variables on the
space-time point (exact solution) may be expressed in terms of theta functions
on the jacobian of this curve. This is the main result of our paper
The effect of Mexidol on magnesium-calcium balance and endothelial dysfunction in operational stress
<p>The aim of the study: to study the effect of mexidol content of ionized calcium and magnesium in erythrocytes and the number of circulating endothelial cells in patients undergoing surgery in the maxillofacial area. Material and methods. The intracellular concentration of calcium and magnesium was measured before the operation, in one, three and five days after the surgery with the help of cytochemical method. Mexidol (100mg) was administered intravenously as a single addition to the standard premedication. Results. After surgery, the intracellular calcium and magnesium content increased. After 24 hours, the magnesium level began to decline, and the calcium content in erythrocytes continued to grow. On day 5, the magnesium concentration in erythrocytes decreased below the initial level, and calcium levels remained significantly elevated. Number of endothelial cells in the blood increased immediately after surgery and magnesium-calcium balance and limits endothelial dysfunction. Mexidol continued growing, reaching a peak on day 5 after surgery. When using mexidol decreased levels of calcium and magnesium levels help prevent falls on the 5th day after surgery, decreased the number of circulating endothelial cells. Conclusion. Mexidol prevents postoperative magnesium violation.</p
The MAO NASU Plate Archive: "observations in the past" of minor planets
The Plate Archive of the Main Astronomical Observatory of the National Academy of Sciences of Ukraine (MAO NASU) includes 20 thousands of direct sky area plates, which have been taken for various astronomical projects during the period of about 50 years. Those plates contain more then hundred thousand images of minor planets with magnitude up to 16.7m. About 10% of minor planets, which may be found on our archive plates were firstly discovered after the time when plates have been taken. So, we can rediscovery them due to the so-called “observations in the past”. In the paper the criteria for choose of objects and methods of their search, identification, and determination of their position are discussed. First results of the search for potentially hazardous asteroids in the MAO plate archive are presented
Inversion asymmetry effect on quantum oscillations in 3-D crystals with Cnv symmetry
The peculiarities of quantum oscillations in bulk semiconductors with Cnv symmetry caused by the lack of their symmetry centre are considered. A quasi-qubic model is used for finding the magnetic levels. The algorithm for numerical calculating the levels in the presence of the tilted magnetic field is suggested. Numerical estimations are performed for Сd₃As₂ and Cd₃₋xZnxAs₂. It is shown that the most suitable conditions for observing the beating effect in these compounds are the high values of the electron concentrations and small angles between the direction of the magnetic field and crystal symmetry axis
Weak localization effect on thermomagnetic phenomena
The quantum transport equation (QTE) is extended to study weak localization
(WL) effects on galvanomagnetic and thermomagnetic phenomena. QTE has many
advantages over the linear response method (LRM): (i) particle-hole asymmetry
which is necessary for the Hall effect is taken into account by the
nonequilibrium distribution function, while LRM requires expansion near the
Fermi surface, (ii) when calculating response to the temperature gradient, the
problem of WL correction to the heat current operator is avoided, (iii)
magnetic field is directly introduced to QTE, while the LRM deals with the
vector potential and and special attention should be paid to maintain gauge
invariance, e.g. when calculating the Nernst effect the heat current operator
should be modified to include the external magnetic field. We reproduce in a
very compact form known results for the conductivity, the Hall and the
thermoelectric effects and then we study our main problem, WL correction to the
Nernst coefficient (transverse thermopower).Comment: 20 pages 2 figure
Free electron lasers based on LINAC-800
The project “FELs and LINAC-800” is being under development at JINR. It is based on an accelerator facility
presented to JINR by NIKHEF, Amsterdam. Analysis has shown that it is possible to build in Dubna a universal
light source with unique characteristics consisting of a complex of Free Electron Lasers (FEL) covering continuously
the wavelength range from far-infrared (150 µm) down to ultraviolet (150 nm). Besides, LINAC-800 could be
used for different applications and as an injector for the next generation synchrotron radiation source.Проект ЛСЭ и ЛИНАК-800 реализуется в ОИЯИ. Он основан на ускорительном оборудовании, предоставленном ОИЯИ NIKHEF (Амстердам). Анализ показывает, что в Дубне станет возможным сооружение универсального источника с уникальными характеристиками, состоящего из комплекса лазеров на свободных электронах (ЛСЭ), покрывающих непрерывно длины волн от дальнего инфракрасного излучения (150 мкм) до ультрафиолета (150 нм).Проект ЛСЕ і ЛІНАК-800 реалізується в ОІЯД. Він заснований на прискорювальному устаткуванні, що було дано ОІЯД NІKHEF (Амстердам). Аналіз показує, що в Дубні стане можливим спорудження універсального джерела з унікальними характеристиками, що складається з комплексу лазерів на вільних електронах (ЛВЕ), що перекривають безперервно довжини хвиль від далекого інфрачервоного випромінювання (150 мкм) до ультрафіолету (150 нм)
First results of the renewed Uragan-2M torsatron
The results of experimental investigation on the vacuum magnetic surfaces in the l=2 torsatron with an additional toroidal field Uragan-2M at wide varying operation parameters are presented. Also the first results on the wall conditioning in the Uragan-2M with the ECR and RF discharges in atmosphere of hydrogen in steady-state mode at low magnetic field, plasma production and heating with RF power are described.Представлено результати експериментального дослідження вакуумних магнітних поверхонь в l=2 торсатроні з додатковим магнітним полем Ураган-2М для широкої зміни операційних параметрів. Також описані перші результати підготовки першої стінки в Урагані-2М за допомогою ЕЦР і ВЧ розрядів в атмосфері водню в стаціонарному режимі при низькому магнітному полі, створення і нагріву плазми ВЧ потужністю.Представлены результаты экспериментального исследования вакуумных магнитных поверхностей в l=2 торсатроне с дополнительным магнитным полем Ураган-2М для широкого изменения операционных параметров. Также описаны первые результаты подготовки первой стенки в Урагане-2М при помощи ЭЦР и ВЧ разрядов в атмосфере водорода в стационарном режиме при низком магнитном поле, создания и нагрева плазмы ВЧ- мощностью
A coarse-grained Monte Carlo approach to diffusion processes in metallic nanoparticles
A kinetic Monte Carlo approach on a coarse-grained lattice is developed for the simulation of surface diffusion processes of Ni, Pd and Au structures with diameters in the range of a few nanometers. Intensity information obtained via standard two-dimensional transmission electron microscopy imaging techniques is used to create three-dimensional structure models as input for a cellular automaton. A series of update rules based on reaction kinetics is defined to allow for a stepwise evolution in time with the aim to simulate surface diffusion phenomena such as Rayleigh breakup and surface wetting. The material flow, in our case represented by the hopping of discrete portions of metal on a given grid, is driven by the attempt to minimize the surface energy, which can be achieved by maximizing the number of filled neighbor cells
All-sky search for long-duration gravitational wave transients with initial LIGO
We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society
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