Photocatalytic Removal of Organic Pollutants from Industrial Wastewater Using TiO₂Catalyst

Degradation of organic pollutants in wastewater was investigated by photocatalysis method using anatase modification of titanium-dioxide (TiO2) catalyst with different structures. Laboratory experiments were carried out with industrial wastewaters consisting of different contents of organic pollutants. Two types of TiO2 catalyst: TiO2 having a size near to nanoparticles (about 3 - 4 micron in size) and the nanostructured 15 nm sized TiO2 were used to find optimum conditions of photocatalytic degradation and removal of organic compounds from wastewater. This paper discusses the effect of various parameters on the degradation rate including the catalyst concentration, process duration as well as the catalytic effectiveness of the TiO2 particles’ size. In addition, the effect of UV and visible light sources on the degradation process was studied. The process performed with nanostructured TiO2 catalyst under visible light was very successfully allowing best degradation of organic compounds.

The Conductivity of Indium Phosphide Irradiated by Fast Electrons

In this work, studied electrical conductivity(s) and annealing of radiation defects in crystals of n-InP are irradiated by electrons energy of 6 MeV and doses of 1017 el/cm2 (centimeter) and 2 × 1017 el/cm2 (centimeter). It is shown that alongside point defects (in the form of complexes with impurity atoms in crystals of n-InP) also form the complex defects of the type of disordered areas, annealing of which proceeds at T > 300°C that binds accumulating radiation defects.

Anisotropy of Critical Fields in MgB_2: Two-Band Ginzburg-Landau Theory for Layered Superconductors

The temperature dependence of the anisotropy parameter of upper critical field γHe2 （T） = Hc2^‖ （T） /Hc2^⊥ （T） and London penetration depth γλ （T） = λ‖（T）/λ⊥ （T） are calculated using two-band Ginzburg-Landau theory for layered superconductors. It is shown that, with decreasing temperature the anisotropy parameter γHc2 （T） is increased, while the London penetration depth anisotropy γλ（T） reveals an opposite behavior. Results of our calculations are in agreement with experimental data for single crystal MgB2 and with other calculations..Results of an analysis of magnetic field Hc1 in a single vortex between superconducting layers are also presented.

Pair-Breaking Critical Current Density of Two-Band Superconductor MgB2

Temperature dependence of tbe pair-breaking critical current density of MgB2, jd（T）, is studied using a two-band Ginzburg-Landau theory. The results are shown to be in good agreement with experimental data for the superconducting magnesium diboride MgB2.

Nonlinear Temperature Dependence of Magnetization of Two-Band Superconductors Near Upper Critical Field

Temperature dependence of the magnetization M （T） of two-band superconductors is studied in the vicinity of upper critical field He2 by using a two-band Ginzburg-Landau （GL） theory. It is shown that magnetization M（T） has a nonlinear character due to positive curvature of upper critical field Hc2（T） and temperature dependence of effective Ginzburg-Landau parameter Neff（T）. The results are shown to be in qualitative agreement with experimental data for the superconducting magnesium diboride, MgB2.

Development of an Effective Method for Preventing Dust Pollution in Stone Quarries Using Petroleum Refinery Wastes

The paper presents a new method for preventing dust pollution in stone quarries using naphthenic wastes of petroleum refineries. The method is based on the use of naphthenate solutions of metals as wetting agents to minimize dust release during stone-cutting process. The studies were carried out in one of the stone quarries of the Absheron peninsula. Initial experiments were conducted by using sodium-naphthenate (RCOONa) solution from alkali wastes of refineries. The results have shown that the use of RCOONa as wetting agent considerably reduces both dust pollution and energy consumption of the used equipment, while increasing the service life of stone-cutting saw. A series of researches were carried out with cupric naphthenate (RCOOCu) to further use the obtained dust-naphthenate mixture in agriculture. The effect of various parameters on the quality of the obtained product was investigated. The investigations have revealed that maximal dust reduction and the good quality of dust-naphthenate mixture were observed with 0.13% solution of RCOOCu at 11° - 13° angle of slope and 100 - 180 rotation∕min. intensity of conveyer.

Photoluminescence of EuGa₂Se₄:Nd³⁺

The photoluminescence (PL) in temperature interval 77 - 300 K is investigated in Eu Ga2Se4:Nd polycrystals. It is established that broad band PL with maximum at 561nm is caused by intracentral transitions 4f65d - 4f7(8S7/2) of Eu2+ ions. The intracentral emission of Nd3+, corresponding to both transitions from 4F3/2 level and higher situated levels, is observed at interband excitation. The essential intensity of transitions from 2H11/2 and 4F9/2 levels is the interested peculiarity of luminescence spectra of Nd3+ in these crystals.

Features of the Conductivity of the Ag8Ge1-xMnxTe6 Solid Solutions

Samples of Ag8Ge1-xMnxTe6 solid solutions with different manganese content (x = 0, 0.05, 0.1, 0.2) were prepared by fusing and further pressing their powders under the pressure of 0.6 GPa. In addition of Mn atoms to the Ag8GeTe6 compound leads to compression of their lattice. All p-type samples acquire a high resistance below the transition at temperatures of 180 - 220 K. The electrical conductivity of all compositions in the range of 220 - 300 K increases due to hopping mechanism, and at temperatures T > 320 K, a semiconductor characteristic is observed. By studying impedance spectra of samples, it was established that at 80 K solid solutions behave like a homogeneous dielectric material. At high temperatures and frequencies of an external electric field, a significant role of grain boundaries in conductivity was revealed. The dielectric anomaly occurring at low frequencies is also associated with an effect that manifests itself in the grain boundary.

Phenomenon of Mutual Compensation of Radiation Donors and Acceptors and Creation of Radiation-Resistant Materials

The phenomenon of mutual compensation of radiation donors and acceptors is discovered in IrtAs-InP solid solutions. This phenomenon is a result of opposite directed radiation processes, taking place in the irradiated InAs-InP solid solutions. The radiation creates donor type defects in the sublattice of InAs and electrons concentration increases. The contrary process occurs in the sublattice of InP. Radiation originates acceptor type defects and the carrier concentration decreases. The noted effect is going on in the all alloy composition. Exact mutual compensation of radiation donors and acceptors is achieved by selecting of the alloys definite composition. As a result, the main parameter of semiconductors-electrons concentration remains constant even under the hard radiation with fluences of Ф = 2 × 10^18 fast neutrons/cm^2. So there has been created radiation-resistant material.

GaSe及相关晶体的历史、现状与未来:具有特异非线性光学特性的层状材料(英文)

概述了高度各向异性的,尤其是无掺杂和掺杂的层状半导体GaSe和相关晶体InSe、GaS和GaSe-GaS（固溶液）的结构特性、光学特性和非线性光学特性的实验研究结果,同时概述了由共焦拉曼和光致发光显微镜研究得到的结果和由声波降解法和激光消融技术得到的GaSe纳米粒的光学性质。重点讨论了-εGaSe的性质,指出其具有最大的光学二阶非线性系数χ,并可结晶成4种不同的多型体（ε,γ,β,δ）,且每个晶胞有以不同数目和排列方式的层状结构。研究认为,在红外和太赫兹光谱波段,GaSe可以被看作是最有应用前景的非线性晶体之一。已发表的1700多篇关于材料物理性质的论文也指出,在THz波段,GaSe是一种具有特异非线性光学特性的材料。通过共焦拉曼显微镜的实验研究,讨论了晶体的域结构和非线性光学性质。除了探讨这些材料最重要的物理性质,还进一步研究了在主边缘附近的光吸收,在红外和太赫兹波段的光致发光、非线性光学性质以及它们的纳米物理性质,这些研究对理解二维晶体结构和其物理性质之间的联系是必要的。由于GaSe及GaSe型晶体具有包含？Se-Ga-Ga-Se-共价键的单一四层结构,因而它们的纳米粒表现出一些特殊的性质。一些GaSe型晶体（InSe,GaTe）的带隙宽度在1.21.5 eV之间,这使得它们及其纳米粒很适合用作光伏材料。

Pressure and Doping Effects on Critical Temperature in MgB_2 and Nonmagnetic Borocarbides within Two-Band Eliashberg Theory

Critical temperature of Mg1-xAlxB2, MgB2-xCx are calculated using two-band Eliashberg theory in intermediate e-ph coupling. Analytical calculations are conducted for different values of doping parameters x in this compounds. Pressure effects on critical temperature in MgB2 and nonmagnetic borocarbide YNi2B2C are also investigated. Results is compared with available experimental data and good agreement is achieved.

Coherent States and a Path Integral for the Relativistic Linear Singular Oscillator

The SU（1,1） coherent states for a relativistic model of the linear singular oscillator are considered. The corresponding partition function is evaluated. The path integral for the transition amplitude between SU（1,1） coherent states is given. Classical equations of the motion in the generalized curved phase space are obtained. It is shown that the use of quasiclassical Bohr Sommerfeld quantization rule yields the exact expression for the energy spectrum.

Remote Pyramid-Shaped Phosphor Coating for Phosphor-Converted White LEDs

Increasing light extraction efficiency is an important task when it comes to manufacturing a powerful white light emitting diode with high luminous flux per watt. In this paper the fabrication of a pyramid-shaped 3-dimensional phosphor coating is reported. It is represented by a phosphor cover, shaped into an array of pyramid like formations. It is proposed that such a structure can improve the light extraction efficiency and the color distribution characteristics of any phosphor-converted white LED. The luminous flux and luminous efficacy are being studied as a function of the forward current across the die. It was found out that with this kind of technique it was possible to achieve an 8% - 14% increase in the efficacy of the pc-LED. This increase of light output power is being attributed to the reduction of the phenomena of total internal reflection (TIR) inside the packaging module.

Nanoporous Silicon-Based Ammonia-Fed Fuel Cells

The objective of the paper is to report results on fabrication, structural, morphological and performance characteristics of novel TiO2/PS/Si, Au/TiO2/PS/Si and Au/PS/Si direct ammonia fuel cells (DAFC) using nanoporous silicon (PS) as proton conducting membrane (instead of traditional polymer Nafion membrane) and TiO2, Au/TiO2 or Au as catalyst layer. Porous silicon layers have been prepared by electrochemical modification of silicon substrates. Films containing titanium dioxide are more efficient catalysts for hydrogen production from ammonia solution. The Au/ TiO2/PS/Si cell exhibited the open circuit voltage 0.87 V and performance of 1.6 mW/cm2 with 50% ammonia solution as fuel at room temperature. Mechanisms of proton transport in nanoporous silicon membrane and generation of electricity in DAFC have been considered. Advantages of investigated direct ammonia fuel cells consist in simplicity of fabrication technology, which can be integrated into standard silicon micro fabrication processes and operation of cells at room temperature. The work demonstrates that the PS based fuel cells have potential for portable applications.