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 o...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.展开更多
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 (cent...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.展开更多
Temperature dependence of the 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 sup...Temperature dependence of the 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.展开更多
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 m...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.展开更多
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(...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.展开更多
Samples of Ag<sub>8</sub>Ge<sub>1-x</sub>Mn<sub>x</sub>Te<sub>6</sub> solid solutions with different manganese content (x = 0, 0.05, 0.1, 0.2) were prepared by fusing an...Samples of Ag<sub>8</sub>Ge<sub>1-x</sub>Mn<sub>x</sub>Te<sub>6</sub> 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 Ag<sub>8</sub>GeTe<sub>6</sub> 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.展开更多
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-di...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.展开更多
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 nanoporo...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.展开更多
文摘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.
文摘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.
基金NATO reintegration grant，TUBITAK research Foundation
文摘Temperature dependence of the 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.
文摘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.
文摘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.
文摘Samples of Ag<sub>8</sub>Ge<sub>1-x</sub>Mn<sub>x</sub>Te<sub>6</sub> 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 Ag<sub>8</sub>GeTe<sub>6</sub> 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.
文摘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.
文摘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.
