324 research outputs found
Landau damping in thin films irradiated by a strong laser field
The rate of linear collisionless damping (Landau damping) in a classical
electron gas confined to a heated ionized thin film is calculated. The general
expression for the imaginary part of the dielectric tensor in terms of the
parameters of the single-particle self-consistent electron potential is
obtained. For the case of a deep rectangular well, it is explicitly calculated
as a function of the electron temperature in the two limiting cases of specular
and diffuse reflection of the electrons from the boundary of the
self-consistent potential. For realistic experimental parameters, the
contribution of Landau damping to the heating of the electron subsystem is
estimated. It is shown that for films with a thickness below about 100 nm and
for moderate laser intensities it may be comparable with or even dominate over
electron-ion collisions and inner ionization.Comment: 15 pages, 2 figure
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The effect of nonlinearity in CO2 heating rates on the attribution of stratospheric ozone and temperature changes
An analysis of the attribution of past and future changes in stratospheric ozone and temperature to anthropogenic forcings is presented. The analysis is an extension of the study of Shepherd and Jonsson (2008) who analyzed chemistry-climate simulations from the Canadian Middle Atmosphere Model (CMAM) and attributed both past and future changes to changes in the external forcings, i.e. the abundances of ozone-depleting substances (ODS) and well-mixed greenhouse gases. The current study is based on a new CMAM dataset and includes two important changes. First, we account for the nonlinear radiative response to changes in CO2. It is shown that over centennial time scales the radiative response in the upper stratosphere to CO2 changes is significantly nonlinear and that failure to account for this effect leads to a significant error in the attribution. To our knowledge this nonlinearity has not been considered before in attribution analysis, including multiple linear regression studies. For the regression analysis presented here the nonlinearity was taken into account by using CO2 heating rate, rather than CO2 abundance, as the explanatory variable. This approach yields considerable corrections to the results of the previous study and can be recommended to other researchers. Second, an error in the way the CO2 forcing changes are implemented in the CMAM was corrected, which significantly affects the results for the recent past. As the radiation scheme, based on Fomichev et al. (1998), is used in several other models we provide some description of the problem and how it was fixed
Intercultural Communication and Values-Based Orientations of Youth: Social Mobility and Problems of Self-Realisation
The ability to interact at the level of interpersonal communication allows to say that young people not only perceive society as an environment for their self-realisation, but also use it to gain new experience, that can determine the development of an individual. The relevance of the study is determined by the fact that each act of communication must be implemented for the purposes of development under certain conditions that affect not only the communication environment itself, but also other forms of interaction at the level of the individual, communality or community. The novelty of the subject matter is determined by the fact that the formation of intercultural communication is possible only if programs of social mobility and, accordingly, cultural exchange are implemented. The authors show that such progress is most likely to be achieved in the external environment, which is determined by the presence of external influences. The authors of the paper primarily refer to this effect as the environment of an educational institution. The leading research method is a sociological survey and the method of analysis, which make it possible to comprehensively consider the value priorities and preferences that are characteristic of modern student youth. The practical significance of the study is determined by structuring and factor analysis, which allows to distribute the cultural layer into various social groups and ensure youth intercultural exchange both in the context of local student communication and in the context of an increase in the level of academic mobility
Investigation converter circuit "voltage-current" for power calibrator
The paper presents alternative circuits for voltage-current converters to be used in the calibrator of fictitious power. The experimental studies have revealed a number of problems related to the stability of the system in deep feedback and zero level stabilization of the amplifier. The circuit solutions given in the article allow elimination of these problems and improve the accuracy of calibrator current calibration. For example, correction/corrective circuits are used to ensure the stability of the converter at deep depths of the feedback, and operational amplifier based circuit solution and compensation condition are proposed to reduce the additional phase shift. To improve the accuracy of the calibration current values specified by the calibrator we propose to connect the feedback circuit to the measuring current transformer. However, further improvement of the accuracy class of the power calibrator is impossible without modern electronic components
Comparative analysis of taxation for special economic zones in Russia and APEC economies
The article is devoted to the analysis of taxation of special economic zones, since special economic zones have become a center of attention in Russia over the latest decades. As objects for the study, the authors selected special economic zones in Russia and the countries participating in the Forum of the Asia-Pacific Economic Cooperation (APEC Forum).
In the article the authors consider history, modern conditions and prospects for the development of special economic zones. The peculiarities of taxations on profits, organizations' property, transport, land, insurance contributions into the non-budget funds, as well as value-added taxation for the residents of the RF special economic zones are analyzed with regard to their types.
The authors assess tax privileges and preferences for some taxes in the special economic zones in Russia and APEC member-countries are evaluated. The main problems of the taxation of the RF special economic zones are articulated together with the possible ways to solve them regarding the experience of APEC economies.
As a result of the study, the authors concluded that to increase the effectiveness of special economic zones in Russia, it is necessary to expand the list of tax benefits to introduce a progressive scale of tax incentives, following the example of APEC countries and to improve legislation in the regulation of special economic zones.peer-reviewe
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Response of the middle atmosphere to CO2 doubling: results from the Canadian Middle Atmosphere Model
The Canadian Middle Atmosphere Model (CMAM) has been used to examine the middle atmosphere response to CO2 doubling. The radiative-photochemical response induced by doubling CO2 alone and the response produced by changes in prescribed SSTs are found to be approximately additive, with the former effect dominating throughout the middle atmosphere. The paper discusses the overall response, with emphasis on the effects of SST changes, which allow a tropospheric response to the CO2 forcing. The overall response is a cooling of the middle atmosphere accompanied by significant increases in the ozone and water vapor abundances. The ozone radiative feedback occurs through both an increase in solar heating and a decrease in infrared cooling, with the latter accounting for up to 15% of the total effect. Changes in global mean water vapor cooling are negligible above ~30 hPa. Near the polar summer mesopause, the temperature response is weak and not statistically significant. The main effects of SST changes are a warmer troposphere, a warmer and higher tropopause, cell-like structures of heating and cooling at low and middlelatitudes in the middle atmosphere, warming in the summer mesosphere, water vapor increase throughout the domain, and O3 decrease in the lower tropical stratosphere. No noticeable change in upwardpropagating planetary wave activity in the extratropical winter–spring stratosphere and no significant temperature response in the polar winter–spring stratosphere have been detected. Increased upwelling in the tropical stratosphere has been found to be linked to changed wave driving at low latitudes
Stratospheric warming influence on the mesosphere/lower thermosphere as seen by the extended CMAM
The response of the upper mesosphere/lower thermosphere region to major
sudden stratospheric warming (SSW) is examined employing temperature, winds,
NOX and CO constituents from the extended Canadian Middle
Atmosphere Model (CMAM) with continuous incremental nudging below 10 hPa
(~ 30 km). The model results considered cover high latitudes
(60–85° N) from 10 to 150 km height for the December–March period
of 2003/2004, 2005/2006 and 2008/2009, when some of the strongest SSWs in
recent years were observed. NOX and CO are used as proxies for
examining transport. Comparisons with ACE-FTS (Atmospheric Chemistry Experiment–Fourier Transform Spectrometer) satellite observations show
that the model represents well the dynamics of the upper mesosphere/lower
thermosphere region, the coupling of the stratosphere–mesosphere, and the
NOX and CO transport. New information is obtained on the upper
mesosphere/lower thermosphere up to 150 km showing that the NOX
volume mixing ratio in the 2003/2004 winter was very perturbed indicating
transport from the lower atmosphere and intense mixing with large
NOX influx from the thermosphere compared to 2006 and 2009. These
results, together with those from other models and observations, clearly show
the impact of stratospheric warmings on the thermosphere
Three-body correlations in direct reactions: Example of Be populated in reaction
The Be continuum states were populated in the charge-exchange reaction
H(Li,Be) collecting very high statistics data ( events) on the three-body ++ correlations. The
Be excitation energy region below MeV is considered, where the
data are dominated by contributions from the and states. It is
demonstrated how the high-statistics few-body correlation data can be used to
extract detailed information on the reaction mechanism. Such a derivation is
based on the fact that highly spin-aligned states are typically populated in
the direct reactions.Comment: submitted to Physical Review
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