Abelian monopoles in finite temperature lattice SU(2) gluodynamics: first study with improved action

The properties of the thermal Abelian color-magnetic monopoles in the maximally Abelian gauge are studied in the deconfinement phase of the lattice SU(2) gluodynamics. To check universality of the monopole properties we employ the tadpole improved Symanzik action. The simulated annealing algorithm combined with multiple gauge copies is applied for fixing the maximally Abelian gauge to avoid effects of Gribov copies. We compute the density, interaction parameters, thermal mass and chemical potential of the thermal Abelian monopoles in the temperature range between Tc and 3Tc. In comparison with earlier findings our results for these quantities are improved either with respect to effects of Gribov copies or with respect to lattice artifacts.Comment: 11 pages, 14 figures, 5 tables; substantially changed version, title change

History and Developments of Semiconductor Lasers

A brief history of the creation of semiconductor lasers is presented. Basic attention is given to injection lasers including homo- and heterojunction laser diodes, quantum-well heterostructures, quantum cascade systems, etc. General steps in the development of the semiconductor lasers and inventions in the injection lasers are described. Theory modeling the spectral and output characteristics of the laser semiconductor sources is discussed. Set of applied semiconductor materials for laser technology and techniques and number of corresponding lasing wavelengths are listed. In addition, principal fields of application of semiconductor lasers and as well as growing total volume in the laser market are involved. Modern trends in semiconductor quantum electronics are also grounded

Multilevel intellectual approach to HTTP-requests legitimacy validation

In the paper a multilevel intellectual approach to HTTP-requests legitimacy validation is proposed. The approach is devised for HTTP-flood DDoS-attacks detection and prevention in telecommunication networks with a web-server as the target attack object. The analysis of HTTP-requests attributes and their signatures is provided. On the basis of the analysis the attributes are separated into several levels that allow us to design a flow analyzer in a form of the multilevel block. Due to a multilevel structure of the flow analyzer a minimization of resources, spent for a request handling, is achieved

Abnormal Character of the Diffusivity-mobility Ratio in Doping Superlattices

The influence of high level of doping in type n-i-p-i crystal structures on electron and hole state distributions is examined. Abnormal behaviour in the diffusivity- mobility ratio due to shortening of the density state tails under excitation of doping Superlattices is described

Rational parameters of drilling-and-blasting operations at mine workings construction in the conditions of PJSC “Zaporizskyi iron-ore plant”

Purpose. Substantiation and choice of rational parameters of drilling-and-blasting operations for mine workings construction with the use of emulsion ex-plosives. Methods. The tasks were solved by a complex method, which includes the analysis of mining and geological conditions of deposition and development of chambers by means of chamber systems of development with the laying of the produced space, applied technology of drilling and blasting in the course of mining and theoretical studies, which were performed using mathematical methods. Findings. As a result of the calculations, a new technological solution was developed to substantiate and select rational parameters of drilling and blasting operations with the use of emulsion explosives during preparatory workings, which will allow to carry out resource saving in carrying out tunneling works. Originality. A new and effective approach is used to determine the location of holes in the bottom of the production, taking into account the energy characteristics of the explosive and the physical and mechanical properties of the rocks. Practical implications. A technological solution is developed to substantiate and select rational parameters of drilling and blasting operations using emulsion explosives for workings, which will allow to carry out resource saving in the production of mining operations

Production of broadband modal gain spectra in asymmetric multiple quantum-well Ga0.47In0.53As/Ga0.18In0.82As0.4P0.6 heterostructures

The modal gain spectra of asymmetric multiple quantum-well Ga0.47In0.53As/Ga0.18In0.82As0.4P0.6 hetero- structures are theoretically analysed within the framework of the four-band kp method. An efficient procedure for obtaining the broadband and almost êat gain spectrum is proposed. The designs of semiconductor radiation sources with different sets of nonuniformly excited quantum wells producing broadband amplification in spectral ranges from 1.28 to 1.525 \mu m and from 1.36 to 1.6 \mu m are calculated

Calculation of energy characteristics for Si1-xGex-Si strucrures with single quantum wells

Energy characteristics of Si1–xGex–Si quantum-size structures with single quantum wells were calculated numerically based on a four-band k⋅p method. Analytical expressions for the Luttinger parameters are obtained as functions of the component composition of Si1–xGex compounds. Analytical expressions for the energy h−ω of optical band-to-band transitions are obtained in an effective mass approximation and agree well with numerical calculations by the k⋅p method. This allows one to determine accurately a range of changes while varying the component compositions and thickness of the active and barrier layers

Carrier transport and screening in n-i-p-i crystals

The variation of the energy spectrum of n-i-p-i crystals under excitation was examined and the influence of the reduction of the screening length on the ratio between the coefficient of diffusion and the mobility of the current carriers was established. It is shown that the filling of subband states by carriers results in an anomalous behaviour of the diffusivity-mobility ratio. The effect occurs in the electric quantum limit and at room temperature as well