355 research outputs found
Determination of the Working Liquids Technical Condition By Analysis of Digital Speckle Images Parameters
The article discusses the practical realization for the optical control method of technical working fluids condition by the analysis of digital speckle images parameters is discussed. The experimental research results on the application of this method for estimation of aviation fuel and motor oil technical condition are presented.
Keywords: motor oil, aviation fuel, speckle, autocorrelation, impurities, diagnostic
Service at the Fortress of Tsaritsyn and Tsaritsyn Service People in the Account Books of the Treasury Court. 1615/16–1621/22
Introduction. The article is devoted to the first mention of people and events related to the fortress of Tsaritsyn restored in 1615 in the account books of the treasury court, starting with the first mention and up to 1622.
Methods and materials. In total, the account books of the treasury court kept records of 36 cases of granting fabrics for the outlined period. These records on services at the fortress contain the names of 72 servicemen including: voivode, 8 boyar’s children, 2 colonels, 5 sotniks and 25 Tsaritsyn streltsy, 8 Tsaritsyn pathfinders. According to published materials of the Order-in-charge Prikaz, the paper analyzes the dynamics of Tsaritsyn garrison restoration correlating with the data of account records.
Analysis. The analysis of systemized records from September 1619 shows that the Tsaritsyn garrison was fully restored after the restoration of the fortress and was able to defend not only the fortress, but also the entire territory controlled by it. The garrison carried out all the basic functions to combat the Cossack robberies on the Volga and cleared areas of steppe roads situated on the West and East of Tsaritsyn from the Azov, Nagai and Cossack robbers.
Results. As a result, the study introduces a valuable set of written sources into scientific use, which made it possible to clarify a whole range of issues and problems of the early history of Tsaritsyn
Age-related changes of the vitreous body
Innovative advances in recent years in the study of pathological changes of the posterior segment of the eye including the use of optical coherence tomography which is considered the gold standard for diagnosing vitreoretinal interface pathology, not only significantly expanded the idea of the most prevalent lesions of the structure of posterior eye segment but also discovered absolutely new aspects of their pathology. The review emphasizes the spreading understanding of vitreous body, its age-related changes in the pathology of the posterior eye segment. Two main interrelated processes occurring in the vitreous body - synchysis and syneresis, gradually increasing with age, are considered. Synchysis process begins at the early age and by the age of 70 reaches 50% of the volume of the vitreous body in 70% of the population. Parallelly, syneresis provides strength and plasticity of the entire vitreous volume due to collagen involved in formation of fibrillar frame. An important role in maintaining a stable and viscoelastic structure of the vitreous body, belonging to hyaluronic acid, is discussed, the level of which remains relatively stable at any age due to its constant synthesis. The accumulated data on the structure of age-related and pathological biodegradation of the vitreous body demonstrates inevitable progression of this process leading to age-related posterior vitreous detachment, which is a detachment of the posterior cortical layers of the vitreous body from subjacent retina. Posterior detachment under the influence of age-related changes in the vitreous body has certain stages - from incomplete juxtafoveolar detachment to complete posterior vitreous detachment with clinical retinal changes corresponding to each stage (idiopathic macular holes, lamellar macular tears, macular fibrosis, vitreomacular traction syndrome, myopic foveoschisis). Complete posterior vitreous detachment usually does not cause anatomical retinal disorders and any clinical forms of its diseases, thus, it can be considered as a natural favorable outcome
Two dimensional electron gas driven by strong alternating electric field
2D Fermi liquid driven by uniform alternating electric field at zero
temperature may remain in quantum coherent non-equilibrium state. We develop a
quasistatic approximation for strong and slow ac-fields and solve the problem
of driven disordered 2D electron gas in high non-overlapping Landau levels. The
broadening of Landau level has the Lorentz form and is inversely proportional
to the amplitude of the ac-field. In the absence of electron-phonon interaction
the electron distribution function is constant within the last Landau level and
the diagonal dc-conductivity is zero. For weak electron-phonon interaction the
dc-conductivity is anisotropic. A kinetic transition from the phonon cooling to
the phonon heating is predicted.Comment: 8 pages, 1 figure REVTE
On the connection between gamma and radio radiation spectra in pulsars
The model of pulsar radio emission is discussed in which a coherent radio
emis-sion is excited in a vacuum gap above polar cap of neutron star. Pulsar X
and gamma radiation are considered as the result of low-frequency radio
emission inverse Comp-ton scattering on ultra relativistic electrons
accelerated in the gap. The influence of the pulsar magnetic field on Compton
scattering is taken into account. The relation of radio and gamma radiation
spectra has been found in the framework of the model.Comment: 15 pages, 3 figures, Russian version accepted to JETP, partly
published in JETP Letters, Vol. 85, #6 (2007
Microwave Photoconductivity in Two-Dimensional Electron Systems due to Photon-Assisted Interaction of Electrons with Leaky Interface Phonons
We calculate the contribution of the photon-assisted interaction of electrons
with leaky interface phonons to the dissipative dc photoconductivity of a
two-dimensional electron system in a magnetic field. The calculated
photoconductivity as a function of the frequency of microwave radiation and the
magnetic field exhibits pronounced oscillations. The obtained oscillation
structure is different from that in the case of photon-assisted interaction
with impurities. We demonstrate that at a sufficiently strong microwave
radiation in the certain ranges of its frequency (or in certain ranges of the
magnetic field) this mechanism can result in the absolute negative
conductivity.Comment: 3 pages, 1 figur
Absolute Negative Conductivity in Two-Dimensional Electron Systems Associated with Acoustic Scattering Stimulated by Microwave Radiation
We discuss the feasibility of absolute negative conductivity (ANC) in
two-dimensional electron systems (2DES) stimulated by microwave radiation in
transverse magnetic field. The mechanism of ANC under consideration is
associated with the electron scattering on acoustic piezoelectric phonons
accompanied by the absorption of microwave photons. It is demonstrated that the
dissipative components of the 2DES dc conductivity can be negative
() when the microwave frequency is
somewhat higher than the electron cyclotron frequency or its
harmonics. The concept of ANC associated with such a scattering mechanism can
be invoked to explain the nature of the occurrence of zero-resistance
``dissipationless'' states observed in recent experiments.Comment: 7 pager, 2 figure
Review of scientific topics for Millimetron space observatory
This paper describes outstanding issues in astrophysics and cosmology that
can be solved by astronomical observations in a broad spectral range from far
infrared to millimeter wavelengths. The discussed problems related to the
formation of stars and planets, galaxies and the interstellar medium, studies
of black holes and the development of the cosmological model can be addressed
by the planned space observatory Millimetron (the "Spectr-M" project) equipped
with a cooled 10-m mirror. Millimetron can operate both as a single-dish
telescope and as a part of a space-ground interferometer with very long
baseline.Comment: The translation of the original article in Physics Uspekhi
http://ufn.ru/ru/articles/2014/12/c
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