524 research outputs found
The mechanism of temperature and pressure changes in the Earth's atmosphere during solar flares
The effect of solar flares on the weather on Earth is examined. It is concluded that the processes which arise in the atmosphere are so intricate that a single calculation of solar activity is insufficient for long-range forecasting. However, combined consideration of processes dependent upon the dynamic instability of the atmosphere and the effect of solar activity will contribute to the improvement of long-range forecasts
Polarization Properties of the "Photon Pistol"
The deterministic single-photon emission by means of STIRAP through the atoms
with degenerate levels is studied. The expression for the polarization matrix
of the emitted photon is obtained and its dependence on the polarization of the
driving laser field and on the initial atomic state is examined.Comment: 13 pages, 3 figure
Single-atom quantum memory with degenerate atomic levels
The storage and retrieval of a single-photon polarization q-bit by means of
STIRAP through the atoms with degenerate levels is studied theoretically for
arbitrary polarization of the driving laser field and arbitrary values of the
angular momenta of resonant atomic levels. The dependence of the probability of
long-term photon storage on the polarization of the driving field and on the
initial atomic state is examined.Comment: 12 pages, 1 figure. arXiv admin note: text overlap with
arXiv:1203.439
Single-photon emission via Raman scattering from the levels with partially resolved hyperfine structure
The probability of emission of a single photon via Raman scattering of laser
pulse on the three-level - type atom in microcavity is studied. The
duration of the pulse is considered to be short enough, so that the hyperfine
structure of the upper level remains totally unresolved, while that of the
lower level is totally resolved. The coherent laser pulse is assumed to be in
resonance with the transition between one hyperfine structure component of the
lower atomic level and all hyperfine structure components of the upper level,
while the quantized cavity field is assumed to be in resonance with the
transition between the other hyperfine structure component of the lower level
and all components of the upper one. The dependence of the photon emission
probability on the mutual orientation of polarization vectors of the cavity
mode and of the coherent laser pulse is analyzed. Particularly, the case is
investigated, when the total electronic angular momentum of the lower atomic
level equals 1/2, which is true for the ground states of alkali atoms employed
in the experiments on deterministic single photon emission. It is shown, that
in this case the probability of photon emission equals zero for collinear
polarizations of the photon and of the laser pulse, and the probability obtains
its maximum value, when the angle between their polarizations equals 60
degrees.Comment: 5 pages, 3 figure
Theoretical foundations of the methods and means of increasing the efficiency of vibration diagnostics of power equipment
The work is devoted to the development and application of computational and experimental methods and means of increasing the efficiency of vibration diagnostics of power equipment, including gas compressor units of gas transmission systems. There are solutions of the problem of natural frequencies and modes of its vibrations to calculate of the levels of power ratio (sensitivity functions) of equipment units and they are summarized in the form of computational models
Determination of stressāstrain relation using instrumented ball indentation at micron scale
Indentation with the spherical shape indenter has been used for long time as the way to measure true stress ā plastic strain curve and corresponding properties: strain-hardening exponent, strength coefficient, yield strength and other values. A different approach has been used to obtain the desired Ļ(Īµ) curve from partial loading-unloading (PUL) force vs depth dependence processing using the analytical solutions, finite element modeling (FEM) and neural networks. The last two methods have primarily laboratory applications, while analytical approach has been used to determine mechanical properties in industrial applications. Automated ball indentation (ABI) [1, 2] is one of those most old established methods, which was mostly used for the pipeline and weld joints control. In current work, we present the results of the application of ABI method for the determination of stress ā strain relation in micrometer range.
Please click Additional Files below to see the full abstract
Determination of stressāstrain relation using instrumented ball indentation at micron scale
Indentation with the spherical shape indenter has been used for long time as the way to measure true stress ā plastic strain curve and corresponding properties: strain-hardening exponent, strength coefficient, yield strength and other values. A different approach has been used to obtain the desired Ļ(Īµ) curve from partial loading-unloading (PUL) force vs depth dependence processing using the analytical solutions, finite element modeling (FEM) and neural networks. The last two methods have primarily laboratory applications, while analytical approach has been used to determine mechanical properties in industrial applications. Automated ball indentation (ABI) [1, 2] is one of those most old established methods, which was mostly used for the pipeline and weld joints control. In current work, we present the results of the application of ABI method for the determination of stress ā strain relation in micrometer range.
Please click Additional Files below to see the full abstract
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