X-Ray Structural Study of 09Nn2Si Steel Welded Joints

The article is devoted to handling a vital scientific and technical problem of improving operational reliability and safety of critical constructions, exploited in Siberia and Far North, by developing of new technological approaches to welding. In the article results of X-ray diffraction examinations of 09Mn2Si steel welded joints are given, produced by different welding operations. Resulting from researches, the authors have concluded that pulse-arc welding is the most preferred welding process as compared with direct current welding

Observation of Spin Relaxation Anisotropy in Semiconductor Quantum Wells

Spin relaxation of two-dimensional electrons in asymmetrical (001) AlGaAs quantum wells are measured by means of Hanle effect. Three different spin relaxation times for spins oriented along [110], [1-10] and [001] crystallographic directions are extracted demonstrating anisotropy of D'yakonov-Perel' spin relaxation mechanism. The relative strengths of Rashba and Dresselhaus terms describing the spin-orbit coupling in semiconductor quantum well structures. It is shown that the Rashba spin-orbit splitting is about four times stronger than the Dresselhaus splitting in the studied structure.Comment: 4 pages, 3 figure

Энергоснабжение изолированных территорий в контексте привлечения инвестиций и развития экономики региона

The study analyses energy supply to isolated areas considering the development of priority areas of the regional economy and assessing the dependence between consumer finances and electricity costs. We examined energy supply problems in the example of the Tuva Republic, the Russian region with vast isolated areas and high prices for energy. We explained the reasons for the increase in electricity costs, including small-scale generation sources based on fossil fuels. The limitations of economically substantiated energy transmission at light loads prevent the connection to a centralised energy supply systems in isolated territories, leading to a decentralised energy supply. Thus, we proposed a methodological toolkit for solving the problem of economic substantiation of the dependence between consumer finances and electricity costs, testing it on the example of the gold mining industry. Our hypothesis relies on technological development opportunities in the field of renewable energy sources to reduce the construction and operation costs of generation facilities. Since the economic feasibility of using renewable energy sources for investors is determined by the dependence of consumer finances on energy generation costs, it is necessary to create energy resource structures depending on different basic conditions. For that purpose, we showed the linear dependence of the profitability of gold mining investment projects on electricity costs. The proposed criteria and methods allow determining the threshold values of the economic efficiency of energy services provided by suppliers and energy produced by self-generating facilities. Based on these results, further research can focus on analysing the impact of electricity costs on the financial parameters of projects to apply innovative energy supply schemes and identifying thresholds of the response of profitability to energy costs reduction for different energy consumption projects. © 2020 Institute of Economics, Ural Branch of the Russian Academy of Sciences. All rights reserved

Outbreak of West Nile virus infection, Volgograd Region, Russia, 1999.

From July 25 to October 1, 1999, 826 patients were admitted to Volgograd Region, Russia, hospitals with acute aseptic meningoencephalitis, meningitis, or fever consistent with arboviral infection. Of 84 cases of meningoencephalitis, 40 were fatal. Fourteen brain specimens were positive in reverse transcriptase-polymerase chain reaction assays, confirming the presence of West Nile/Kunjin virus

Fixed points and amenability in non-positive curvature

Consider a proper cocompact CAT(0) space X. We give a complete algebraic characterisation of amenable groups of isometries of X. For amenable discrete subgroups, an even narrower description is derived, implying Q-linearity in the torsion-free case. We establish Levi decompositions for stabilisers of points at infinity of X, generalising the case of linear algebraic groups to Is(X). A geometric counterpart of this sheds light on the refined bordification of X (\`a la Karpelevich) and leads to a converse to the Adams-Ballmann theorem. It is further deduced that unimodular cocompact groups cannot fix any point at infinity except in the Euclidean factor; this fact is needed for the study of CAT(0) lattices. Various fixed point results are derived as illustrations.Comment: 33 page

Isolation of two strains of West Nile virus during an outbreak in southern Russia, 1999.

From July to September 1999, a widespread outbreak of meningoencephalitis associated with West Nile virus (Flavivirus, Flaviviridae) occurred in southern Russia, with hundreds of cases and dozens of deaths. Two strains of West Nile virus isolated from patient serum and brain-tissue samples reacted in hemagglutination-inhibition and neutralization tests with patients' convalescent-phase sera and immune ascites fluid from other strains of West Nile virus

Consequences of local gauge symmetry in empirical tight-binding theory

A method for incorporating electromagnetic fields into empirical tight-binding theory is derived from the principle of local gauge symmetry. Gauge invariance is shown to be incompatible with empirical tight-binding theory unless a representation exists in which the coordinate operator is diagonal. The present approach takes this basis as fundamental and uses group theory to construct symmetrized linear combinations of discrete coordinate eigenkets. This produces orthogonal atomic-like "orbitals" that may be used as a tight-binding basis. The coordinate matrix in the latter basis includes intra-atomic matrix elements between different orbitals on the same atom. Lattice gauge theory is then used to define discrete electromagnetic fields and their interaction with electrons. Local gauge symmetry is shown to impose strong restrictions limiting the range of the Hamiltonian in the coordinate basis. The theory is applied to the semiconductors Ge and Si, for which it is shown that a basis of 15 orbitals per atom provides a satisfactory description of the valence bands and the lowest conduction bands. Calculations of the dielectric function demonstrate that this model yields an accurate joint density of states, but underestimates the oscillator strength by about 20% in comparison to a nonlocal empirical pseudopotential calculation.Comment: 23 pages, 7 figures, RevTeX4; submitted to Phys. Rev.

Energy Supply to Isolated Areas: Attracting Investment and Developing Regional Economy

The study analyses energy supply to isolated areas considering the development of priority areas of the regional economy and assessing the dependence between consumer finances and electricity costs. We examined energy supply problems in the example of the Tuva Republic, the Russian region with vast isolated areas and high prices for energy. We explained the reasons for the increase in electricity costs, including small-scale generation sources based on fossil fuels. The limitations of economically substantiated energy transmission at light loads prevent the connection to a centralised energy supply systems in isolated territories, leading to a decentralised energy supply. Thus, we proposed a methodological toolkit for solving the problem of economic substantiation of the dependence between consumer finances and electricity costs, testing it on the example of the gold mining industry. Our hypothesis relies on technological development opportunities in the field of renewable energy sources to reduce the construction and operation costs of generation facilities. Since the economic feasibility of using renewable energy sources for investors is determined by the dependence of consumer finances on energy generation costs, it is necessary to create energy resource structures depending on different basic conditions. For that purpose, we showed the linear dependence of the profitability of gold mining investment projects on electricity costs. The proposed criteria and methods allow determining the threshold values of the economic efficiency of energy services provided by suppliers and energy produced by self-generating facilities. Based on these results, further research can focus on analysing the impact of electricity costs on the financial parameters of projects to apply innovative energy supply schemes and identifying thresholds of the response of profitability to energy costs reduction for different energy consumption projects.Анализ электроснабжения изолированных территорий с учетом развития приоритетных направлений экономики региона и оценки чувствительности финансовых параметров потребителей к затратам на электроэнергию определили интерес авторов к данной проблематике и являются целью исследования. В статье представлен синтез проблем энергоснабжения на примере Республики Тыва как одного из регионов с обширными территориями изолированного энергоснабжения и с высокими ценами на энергоресурсы. Даны причины роста стоимости электроэнергии, в том числе и от источников малой генерации, работающих на ископаемых видах топлива. Показано, что ограниченность границ экономически обоснованной передачи электроэнергии при малых нагрузках является основным препятствием для подключения к централизованным системам энергоснабжения на изолированных территориях и ориентирует на преимущественно децентрализованное снабжение. Предложен инструментарий, в соответствии с которым на примере отрасли золотодобычи проводится экономическое обоснование чувствительности финансовых параметров потребителя к стоимости электроэнергии. Авторская гипотеза основана на возможностях технологического развития в области возобновляемых источников энергии, сопровождающегося снижением стоимости строительства объектов их генерации и их эксплуатации. Обосновано, что поскольку экономическая целесообразность использования возобновляемых источников энергии для инвесторов определяется с учетом степени зависимости финансовых параметров потребителей от существующих затрат на генерацию, требуется формирование структуры источников энергии при различных исходных условиях. Для решения этой задачи представлена линейная зависимость рентабельности проектов золотодобычи от стоимости электроэнергии. Предложенные критерии и методы определения пороговых значений экономической эффективности получаемых энергетических услуг от поставщика и электроэнергии, производимой объектами собственной генерации, позволят на стадии дальнейших исследований производить индивидуальный анализ влияния стоимости электроэнергии на финансовые параметры проектов для применения инновационных схем энергоснабжения и на практике выявлять пороги чувствительности рентабельности к снижению затрат на электроэнергию по проектам с различными объемами энергопотребления

Induced Parity Nonconserving Interaction and Enhancement of Two-Nucleon Parity Nonconserving Forces

Two-nucleon parity nonconserving (PNC) interaction induced by the single-particle PNC weak potential and the two-nucleon residual strong interaction is considered. An approximate analytical formula for this Induced PNC Interaction (IPNCI) between proton and neutron is derived ($Q({\bf r} {\bf \sigma}_{p} \times {\bf \sigma}_{n}) \delta({\bf r}_{p}-{\bf r}_{n})$), and the interaction constant is estimated. As a result of coherent contributions from the nucleons to the PNC potential, IPNCI is an order of magnitude stronger ($\sim A^{1/3}$) than the residual weak two-nucleon interaction and has a different coordinate and isotopic structure (e.g., the strongest part of IPNCI does not contribute to the PNC mean field). IPNCI plays an important role in the formation of PNC effects, e.g., in neutron-nucleus reactions. In that case, it is a technical way to take into account the contribution of the distant (small) components of a compound state which dominates the result. The absence of such enhancement ($\sim A^{1/3}$) in the case of T- and P-odd interaction completes the picture.Comment: Phys. Rev. C, to appear; 17 pages, revtex 3, no figure