350 research outputs found
Формувач сигналів із частотно-часовим кодуванням на основі генератора на комбінаційних частотах
Possibility of the use of oscillator on combination frequencies as a generator of wideband signals with the frequency-time coding is examinedРассматривается возможность использования генератора на комбинационных частотах в качестве формирователя широкополосных шумоподобных сигналов с частотно-временным кодированиемРозглядається можливість використання генератора на комбінаційних частотах в якості формувача широкосмугових шумоподібних сигналів із частотно-часовим кодуванням
Теплообмен при течении Куэтта с учетом теплоты трения
An approximate analytical solution of a non-linear problem concerning heat transfer in the liquid at Couette flow with due account of friction heat has been obtained on the basis of the Kantarovich orthogonal method. The solution has made it possible to carry out temperature investigations at small values of an axial coordinate. Being obtained in the fifth approximation the solution has permitted for the first time to value liquid temperature within the range of the axial spatial coordinate. The analysis of the obtained results has revealed that a temperature maximum shift to motionless flow has been observed at small values of the axial coordinate.It is possible to make a conclusion that in order to protect devices that are moving with high speed in various media it is necessary to organize boundary layer disruption that allows to avoid stabilization of a temperature field in a flow which promotes wall over-heating due to energy dissipation.На основе ортогонального метода Л. В. Канторовича получено приближенное аналитическое решение нелинейной задачи теплообмена в жидкости при течении Куэтта с учетом теплоты трения, позволяющее проводить исследования температуры для малых значений продольной координаты.Полученное в пятом приближении решение позволило впервые выполнить оценку температуры жидкости в диапазоне продольной пространственной координаты. Анализ полученных результатов показал, что при малых значениях продольной координаты наблюдается смещение максимума температуры в сторону неподвижного потока.можно сделать вывод о том, что для защиты устройств, движущихся с высокой скоростью в разных средах, следует так организовать срыв пограничного слоя, чтобы не происходила стабилизация температурного поля в потоке, способствующая перегреву стенки от диссипации энергии
Comment on `Dynamical properties of small polarons'
We show that the conclusion on the breakdown of the standard small polaron
theory made recently by E.V. deMello and J. Ranninger (Phys. Rev. B 55, 14872
(1997)) is a result of an incorrect interpretation of the electronic and
vibronic energy levels of the two-site Holstein model. The small polaron
theory, when properly applied, agrees well with the numerical results of these
authors. Also we show that their attempt to connect the properties of the
calculated correlation functions with the features of the intersite electron
hopping is unsuccessful.Comment: To appear in Phys. Rev.
Automation of monitoring in gas producing company
Specific character of monitoring in gas producing company has been considered. Corporate geoinformation system «Magistral-Vostok» for controlling gas producing enterprises was suggested, the experience of this system introduction in «Vostokgasprom» was describe
Spin-orbit Hanle effect in high-mobility quantum wells
We study the depolarization of optically oriented electrons in quantum wells
subjected to an in-plane magnetic field and show that the Hanle curve
drastically depends on the carrier mobility. In low-mobility structures, the
Hanle curve is described by a Lorentzian with the width determined by the
effective g-factor and the spin lifetime. In contrast, the magnetic field
dependence of spin polarization in high-mobility quantum wells is nonmonotonic:
The spin polarization rises with the magnetic field induction at small fields,
reaches maximum and then decreases. We show that the position of the Hanle
curve maximum can be used to directly measure the spin-orbit Rashba/Dresselhaus
magnetic field.Comment: 4 pages, 3 figure
Формирователь сигналов с частотно-временным кодированием на основе генератора на комбинационных частотах
Розглядається можливість використання генератора на комбінаційних частотах в якості формувача широкосмугових шумоподібних сигналів із частотно-часовим кодуваннямPossibility of the use of oscillator on combination frequencies as a generator of wideband signals with the frequency-time coding is examinedРассматривается возможность использования генератора на комбинационных частотах в качестве формирователя широкополосных шумоподобных сигналов с частотно-временным кодирование
Development of technology elements for growing of perennial sorghum
Optimal sowing time for perennial sorghum under irrigation is when soil temperature at the depth of sowing reaches up to 10–11 °С, harvesting for the green mass has to be done when panicle is situated on the stem in 10 sm from the flag leaf and hight of cut must be 11 sm
Аналіз результатів рейтингування науково-педагогічних працівників Національного гірничого університету за 2011 рік
The assessment of efficiency of the detander-generator installation at the Syzran’ Power Plant
This paper describes the results of thermal and economic calculations of the detander-generator installation at the Syzran’ Power Plant.Представлены результаты теплового и экономического расчетов детандер-генераторной установки Сызранской ТЭЦ
Polaronic excitations in CMR manganite films
In the colossal magnetoresistance manganites polarons have been proposed as
the charge carrier state which localizes across the metal-insulator transition.
The character of the polarons is still under debate. We present an assessment
of measurements which identify polarons in the metallic state of
La{2/3}Sr{1/3}MnO{3} (LSMO) and La{2/3}Ca{1/3}MnO{3} (LCMO) thin films. We
focus on optical spectroscopy in these films which displays a pronounced
resonance in the mid-infrared. The temperature dependent resonance has been
previously assigned to polaron excitations. These polaronic resonances are
qualitatively distinct in LSMO and LCMO and we discuss large and small polaron
scenarios which have been proposed so far. There is evidence for a large
polaron excitation in LSMO and small polarons in LCMO. These scenarios are
examined with respect to further experimental probes, specifically charge
carrier mobility (Hall-effect measurements) and high-temperature
dc-resistivity.Comment: 16 pages, 10 figure
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