Nonequilibrium electron spin polarization in a double quantum dot. Lande mechanism

In moderately strong magnetic fields, the difference in Lande g-factors in each of the dots of a coupled double quantum dot device may induce oscillations between singlet and triplet states of the entangled electron pair and lead to a nonequilibrium electron spin polarization. We will show that this polarization may partially survive the rapid inhomogeneous decoherence due to random nuclear magnetic fields.Comment: New version contains figures. New title better reflects the content of the pape

From a forecasting methodology for the electric energy consumption of mono-towns to its sustainability

The need of Russia for a resource-innovative energy strategy for the period up to 2035 makes it urgent to create a methodology of strategic forecasting for the electric energy consumption of mono-towns, which will result in the efficient development of a power supply system, ensuring territories’ sustainability. For this purpose, it is necessary to consider a mono-town as a complete system, a living organism with a definite life cycle and structure of energy consumers. The authors offer a technocoenosis approach to carry out the ranking and structural analysis of the electric energy consumption of one of the Sverdlovsk region’s mono-towns, taking into account dynamics in population, enterprises, organizations and institutions for the period of 5 years. The provided analysis makes it possible to judge the technocoenosis optimality using characteristic exponent β, depending on the structural features of the territory. The authors developed an algorithm for electric energy consumption forecasting, based on Support Vector Machines (SVM), which takes into account the electric energy of mono-towns’ consumers and the climatic factors. Forecasting accuracy was achieved using cross-validation of the input data in order to optimize the training model. The corresponding changes in electric energy consumption, when a characteristic exponent is optimal, will result in a target forecast that provides the sustainable development of mono-towns. © 2014 WIT Press.International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

Correction of Y-Branches on Proton-exchanged Waveguides in Lithium Niobate By Femtosecond Writing Technology

Correction Y-branches power dividers of the multi-function integrated optics chips on proton-exchanged waveguides in lithium niobate by the technology of direct femtosecond laser writing were investigated. Optimal correction parameters and their influence on temperature stability of Y-splitter are determined. Keywords: lithium niobate, Y-splitters, proton exchange, femtosecond writing, refractive index, integrated optics

Finite element modeling of multiple electrode submerged arc welding of large diameter pipes

For the process of multiple-electrode submerged arc welding (MESAW) of large- diameter pipes (LDP) a mathematical model has been developed with a numerical solution in the software product "SYSWELD". The paper defines the parameters of double ellipsoid model of heat sources by J. Goldak. Using regression analysis of experimental data empirical formulas for calculating geometrical parameters of heat sources model by J. Goldak and deposition rate were developed for welding with direct current on positive polarity and alternating current. The model allows to predict the shape of weld and to estimate analytically the cooling rate in the heat affected zone (HAZ). The developed model and its numerical solutions with sufficient accuracy for practical calculations reflect the process of longitudinal welding of LDP. © 2019 IOP Publishing Ltd

Experimental investigation of the high-temperature air heating effect on the model artificial gas combustion process

A description of the experimental rig is presented. The effect of combustion air high-temperature (up to 800?C) heating on the model artificial gas combustion process is described. The model artificial gas is a CO-N2 mixture. A comparison of the premixed and diffusion flame lower explosive limits is carried out. Experimental data are compared with open access published data of production of artificial gas-fired CCPP. © 2019 Published under licence by IOP Publishing Ltd.The work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006

Development and evaluation of the organization`s logistics strategy based on the application of bifurcation theory

The article considers the main approaches to the development and evaluation of the organization’s logistics strategy based on the application of bifurcation theory. The paper notes that the greatest competitive advantages in the process of carrying out activities can be obtained by the company when designing a unique logistics strategy based on the individual features of the organization’s logistics system. The authors reveal that the bifurcation theory allows you to determine the conditionality of a qualitative dynamic change in the behavior of a logistics system by an infinitesimal change in certain parameters of the system. As part of the assessment of the organization’s logistics management strategy, bifurcation theory forms the basis for determining shift in the qualitative parameter of the system and makes it possible to assess the effect of this parameter on the behavior of the entire system as a whole and each functional subsystem separately. The study reflects that it is possible to determine the critical values of individual variables, when overcoming which the logistics system itself goes into unstable state. The main concept defining the process of critical transition of the state of the logistic system is the bifurcation point

Free Energy of an SU(2) Model of (2+1)-dimensional QCD in the Constant Condensate Background

Gluon and quark contributions to the thermodynamic potential (free energy) of a (2+1)-dimensional QCD model at finite temperature in the background of a constant homogeneous chromomagnetic field H combined with A_0 condensate are calculated. The role of the tachyonic mode in the gluon energy spectrum is discussed. A possibility of the free energy global minimum generation at nonzero values of H and A_0 condensates is investigated.Comment: LaTeX 2e, 14 pages, 6 eps figures, some miscalculations were correcte

The Design Optimization and Experimental Investigation of the 4.4 μm Raman Laser Basedon Hydrogen-filled Revolver Silica Fiber

Optical properties of hollow-core revolver fibers are numerically investigated depending on various parameters: the hollow-core diameter, the capillary wall thickness, the values of the minimum gap between the capillaries, the number of capillaries in the cladding and the type of glass (silica and chalcogenide). Preliminary, similar calculations are made for simple models of hollow-core fibers. Based on the obtained results, the optimal design of the revolver fiber for Raman laser frequency conversion (1.56 μm → 4.4 μm in 1H2) was determined. As a result, efficient ns-pulsed 4.42 μm Raman laser based on 1H2-filled revolver silica fiber is realized. Quantum efficiency as high as 36 % is achieved and output average power as high as 250 mW is demonstrated