High photovoltages in ferroelectric ceramics

The short-circuit currents and photo-emfs were measured for various ceramics including barium titanate, lead metaniobate, and lead titanate. It is suggested that the emfs and currents arise from the presence of photoconductor-insulator sandwiches in the presence of space-charge-produced internal fields. Results are in agreement with the proposed theory and indicate that the ferroelectric ceramics are not only producers of high-voltage photoelectricity but a photo-battery, the polarity and magnitude of which can be switched by application of an electrical signal

Symmetry classes for even-order tensors

The purpose of this article is to give a complete and general answer to the recurrent problem in continuum mechanics of the determination of the number and the type of symmetry classes of an even-order tensor space. This kind of investigation was initiated for the space of elasticity tensors. Since then, different authors solved this problem for other kinds of physics such as photoelectricity, piezoelectricity, flexoelectricity, and strain-gradient elasticity. All the aforementioned problems were treated by the same computational method. Although being effective, this method suffers the drawback not to provide general results. And, furthermore, its complexity increases with the tensorial order. In the present contribution, we provide general theorems that directly give the sought results for any even-order constitutive tensor. As an illustration of this method, and for the first time, the symmetry classes of all even-order tensors of Mindlin second strain-gradient elasticity are provided.Comment: Mathematics and Mechanics of Complex Systems (2013) (Accepted

Results of experiment by work grid-connected photovoltaic station in annual cycle

В работе представлены результаты экспериментального исследования годовой выработки электроэнергии фотоэлектрической станцией, имеющей прямое соединение с электрической сетью. Установлено, что коэффициенты использования установленной мощности подобной ФЭС для условий Уральского региона находятся в интервале 7-11 %.The results of an experimental study of the annual electricity production of photovoltaic station which has a direct connection to the electrical grid. It was found that the capacity factor for grid – connected photovoltaic stations in the conditions of the Ural region is about of 7-11%

Effects of Temperature and Near Ultraviolet Light on Current-Voltage Characteristics of Colemanite

We investigate current-voltage (I-V) characteristics of the ferroelectric material colemanite at room temperature, at a high temperature, and also under the influence of near ultraviolet light. We demonstrate that all three I-V plots exhibit hysteresis effects, and these new results shed new light on the resistance of colemanite. These novel properties are explained on the basis of its microstructure indicating potential applications in devices with negative resistance as well as in photovoltaic devices.Comment: 5 pages, 4 figure

Effects of Ni doping on photocatalytic activity of TiO(2) thin films prepared by liquid phase deposition technique

The TiO(2) thin films doped by Ni uniformly and non-uniformly were prepared on glass substrate from an aqueous solution of ammonium hexa-fluoro titanate and NiF(2) by liquid phase deposition technique. The addition of boric acid as an F(-) scavenger will shift the equilibrium to one side and thereby deposition of the film is progressed. The rate of the reaction and the nature of deposition depend on growing time and temperature. The resultant films were characterized by XRD, EDAX, UV and SEM. The result shows that the deposited films have amorphous background, which becomes crystalline at 500 degrees C. The EDAX data confirms the existence of Ni atoms in TiO(2) matrix. XRD analysis reveals the peaks corresponding to Ni but no peak of crystalline NiO was found. The transmittance spectra of Ni uniformly and non-uniformly doped TiO(2) thin films show 'blue shift and red shift', respectively. Ni-doped TiO(2) thin films can be used as photocatalyst for the photodegradation of methyl orange dye. It was found that, organic dye undergoes degradation efficiently in presence of non-uniformly Ni-doped TiO(2) thin films when compared to uniformly doped films and pure TiO(2) films under visible light. The photocatalytic activity increases with increase in the concentration of Ni in case of nonuniformly doped thin films but decreases with the concentration when uniformly doped thin films were used

Перспективы развития солнечной электроэнергетики в Украине

Представлена концепция создания фотоэнергетической отрасли в Украине, базирующаяся на использовании тонкопленочной ("рулонной") технологии.Представлена концепція створення фотоенергетичної галузі в Україні, що базується на використанні тонкоплівкової ("рулонної") технології.The conception of formation of photoenergy industry in Ukraine based on using of thin-film ("roll") technology is represented