Theoretical and experimental investigation of the destruction of graphites in a flow of dissociated air

A method is presented for calculating the heating and erosion of blunt bodies made of graphite in a high-enthalpy flow of dissociated air, assuming chemical equilibrium on the surface and taking account of the thermal effects of combustion and sublimation of graphite. The analysis involves the use of a finite difference scheme to solve an equation of unsteady heat conduction. Attention is given to the equilibrium vaporization of C, C2 and C3 molecules. The calculations agree well with experimental data for a wide range of temperatures and stagnation pressures

Analysis of optical magnetoelectric effect in GaFeO_3

We study the optical absorption spectra in a polar ferrimagnet GaFeO_3. We consider the E1, E2 and M1 processes on Fe atoms. It is shown that the magnetoelectric effect on the absorption spectra arises from the E1-M1 interference process through the hybridization between the 4p and 3d states in the noncentrosymmetry environment of Fe atoms. We perform a microscopic calculation of the spectra on a cluster model of FeO_6 consisting of an octahedron of O atoms and an Fe atom displaced from the center with reasonable values for Coulomb interaction and hybridization. We obtain the magnetoelectric spectra, which depend on the direction of magnetization, as a function of photon energy in the optical region 1.0-2.5 eV, in agreement with the experiment.Comment: 18 pages, 5 figure

Features of optical characteristics of atmospheric aerosol in the Middle Urals

The results of studies into the aerosol optical depth (AOD) for the atmosphere in the Middle Urals in the spectrum range of 0.34-1.02 μm for 2004-2010 is presented. The interannual, annual, seasonal, and daily variations in the AOD are analyzed. The major statistical characteristics of the AOD, the parameters of the probability density function of distributions over different wave lengths, and the parameters of Angstrom's formula for the different seasons are calculated. The monitoring stations in the Russian segment of the AERONET network are ranked with respect to the AOD value. A shift from March to May in the spring maximum of the AOD is revealed in comparison with the results of the actinometric observations for the period of 1960-1986. A qualitative assessment is given to the influence of forest and peat fires in the region on the AOD. A classification of the states of aerosol haze in the atmosphere according to the AOD values is proposed. © 2013 Pleiades Publishing, Ltd

Исследование методов оценивания стабильности взаимного поведения стохастических процессов

The sensitivity of some methods for estimating the mutual dynamic stability of stochastic processes with given correlative properties was studied in relation to the phase detuning between the processes. Two classes of normally distributed random stochastic processes are considered: the processes with short-term correlation and the processes with a long-term correlation, characterized by the specified Hurst coefficients.На примере тестовых процессов с заданными корреляционными свойствами исследована чувствительность методов оценивания стабильности взаимной динамики стохастических процессов к фазовой расстройке между ними. Рассмотрены два класса нормально распределенных стохастических случайных процессов: процессы с кратковременной зависимостью и процессы с долговременной зависимостью, характеризующиеся заданным показателем Херста

Исследование методов оценивания стабильности взаимного поведения стохастических процессов

The sensitivity of some methods for estimating the mutual dynamic stability of stochastic processes with given correlative properties was studied in relation to the phase detuning between the processes. Two classes of normally distributed random stochastic processes are considered: the processes with short-term correlation and the processes with a long-term correlation, characterized by the specified Hurst coefficients.На примере тестовых процессов с заданными корреляционными свойствами исследована чувствительность методов оценивания стабильности взаимной динамики стохастических процессов к фазовой расстройке между ними. Рассмотрены два класса нормально распределенных стохастических случайных процессов: процессы с кратковременной зависимостью и процессы с долговременной зависимостью, характеризующиеся заданным показателем Херста

Role of PI3K/AKT/mTOR signaling pathway and sirtuin genes in chronic obstructive pulmonary disease development

Chronic obstructive pulmonary disease (COPD) is a multifactorial disease of the respiratory system which develops as a result of a complex interaction of genetic and environmental factors closely related to lifestyle. We aimed to assess the combined effect of the PI3K/AKT/mTOR signaling pathway (PIK3R1, AKT1, MTOR, PTEN) and sirtuin (SIRT1, SIRT3, SIRT6) genes to COPD risk. SNPs of SIRT1 (rs3758391, rs3818292), SIRT3 (rs3782116, rs536715), SIRT6 (rs107251), AKT1 (rs2494732), PIK3R1 (rs10515070, rs831125, rs3730089), MTOR (rs2295080, rs2536), PTEN (rs701848, rs2735343) genes were genotyped by real-time polymerase chain reaction (PCR) among 1245 case and control samples. Logistic regression was used to detect the association of SNPs in different models. Linear regression analyses were performed to estimate the relationship between SNPs and lung function parameters and smoking pack-years. Significant associations with COPD were identified for SIRT1 (rs3818292) (P = 0.001, OR = 1.51 for AG), SIRT3 (rs3782116) (P = 0.0055, OR = 0.69) and SIRT3 (rs536715) (P = 0.00001, OR = 0.50) under the dominant model, SIRT6 (rs107251) (P = 0.00001, OR = 0.55 for СT), PIK3R1: (rs10515070 (P = 0.0023, OR = 1.47 for AT), rs831125 (P = 0.00001, OR = 2.28 for AG), rs3730089 (P = 0.0007, OR = 1.73 for GG)), PTEN: (rs701848 (P = 0.0015, OR = 1.35 under the log-additive model), and rs2735343 (P = 0.0001, OR = 1.64 for GC)). A significant genotype-dependent variation of lung function parameters was observed for SIRT1 (rs3818292), SIRT3 (rs3782116), PIK3R1 (rs3730089), and MTOR (rs2536). Gene-gene combinations that remained significantly associated with COPD were obtained; the highest risk of COPD was conferred by a combination of G allele of the PIK3R1 (rs831125) gene and GG of SIRT3 (rs536715) (OR = 3.45). The obtained results of polygenic analysis indicate the interaction of genes encoding sirtuins SIRT3, SIRT2, SIRT6 and PI3KR1, PTEN, MTOR and confirm the functional relationship between sirtuins and the PI3K/AKT/mTOR signaling pathway

Electromagnetically induced magnetochiral anisotropy in a resonant medium

Chirality has been extensively studied for well over a century, and its potential applications range from optics to chemistry, medicine, and biology. Ingenious experiments have been designed to measure this naturally small effect. Here we discuss the possibility of producing a medium having a large chiral effect by using the ideas of coherent control. The coherent fields resonant with appropriate transitions in atomic or molecular systems can be used to manipulate the optical properties of a medium. We demonstrate experimentally very large magnetochiral anisotropy by using electromagnetic fields in atomic Rb vapors.Peer reviewedPhysic

Development of a Measuring Complex to Monitor the Concentration of Atmospheric Aerosol and Meteorological Parameters in the Surface Air

The development of a measuring complex to monitor the concentration of atmospheric aerosol PM2.5 and meteorological parameters of the surface air is presented. The main components of the complex are discussed, the concept of a network for environmental studies is introduced. Some results of aerosol.Исследование выполнено при финансовой поддержке РФФИ в рамках научного проекта № 19-05-50138

Interplay of non-linear elasticity and dislocation-induced superfluidity in solid Helium-4

The mechanism of the roughening induced partial depinning of gliding dislocations from Helium-3 impurities is proposed as an alternative to the standard "boiling off". We give a strong argument that Helium-3 remains bound to dislocations even at large temperatures due to very long equilibration times. A scenario leading to the similarity between elastic and superfluid responses of solid Helium-4 is also discussed. Its main ingredient is a strong suppression of the superfluidity along dislocation cores by dislocation kinks (D. Aleinikava, et. al., arXiv:0812.0983). These kinks, on one hand, determine the temperature and Helium-3 dependencies of the generalized shear modulus and, on the other hand, control the superfluid response. Several proposals for theoretical and experimental studies of solid Helium-4 are suggested.Comment: final version accepted to the special JLTP issue on Supersolid, 16 pages, 6 figures: typos corrected, more explanations give