Ljuboje Z.,University of East Sarajevo
Electronics | Year: 2015
The photorefractive effect presents a periodical change of the refractive index of an optical environment under the influence of a coherent light. An interesting phenomenon which occurs at this effect is optical phase conjugation (PC). Photorefractive oscillators, that is photorefractive mirrors present important decides in photorefractive optics and their function is based on photorefractive effect. In these oscillators, a phase-conjugated light beam occurs. The basic characteristics of photorefractive oscillators, such as reflectivity, the existance of the oscillation threshold and the threshold of the coupling strength are explained by the so-called grating-action method. This is analysed on a ring oscillator, semilinear mirror and linear mirror.
Armakovic S.,University of Novi Sad |
Armakovic S.J.,University of Novi Sad |
Pelemis S.S.,University of East Sarajevo |
Setrajcic J.P.,University of Novi Sad
Superlattices and Microstructures | Year: 2015
Optoelectronic properties of ultra-thin boron nitride nanotubes and charge carrier hopping properties between them were investigated within density functional theory. The study encompassed calculations of optoelectronic quantities, such as reorganization energies, oxidation and reduction potentials and charge carrier hopping rates between mentioned nanotubes. Charge coupling was calculated applying full quantum mechanical treatment, while Marcus theory was used for calculations of charge carrier hopping rates. Results indicate differences between investigated types of boron nitride nanotubes. With the increase in dimensions of boron nitride nanotubes optoelectronic properties are improving, while charge carrier hopping rates are the highest for (6, 0) boron nitride nanotube. © 2014 Elsevier Ltd. All rights reserved.
Kolarz P.,University of Belgrade |
Miljkovic B.,Merni Instrumenti D.O.O. |
Curguz Z.,University of East Sarajevo
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2012
Mono-electrode self "zeroing" air-ion counter and mobility (size) scanning spectrometer (CDI-011) based on the Gerdien aspirated condenser principle has been developed. Instrument is intended for short- and long-term indoor and outdoor air-ion concentration measurements and scanning of air-ions by mobility. Measuring small currents (typically 10 -14 A) generated by the air-ions in outdoor conditions is demanding and causes many problems related to change of temperature, relative humidity, wind and electromagnetic noise. Also, measuring of both ion polarities with mono electrode detector require alternate changes of the polarizing voltage sign which produces capacitive current spikes. Various techniques, including "zeroing" method, have been applied to successfully overcome most of these measuring interferences. © 2011 Elsevier B.V. All rights reserved.
Maksimovic M.,University of East Sarajevo |
Stojanovic G.M.,University of Novi Sad |
Radovanovic M.,University of Novi Sad |
Malesev M.,University of Novi Sad |
And 3 more authors.
Construction and Building Materials | Year: 2012
In this paper, the application of a passive sensor for measuring the moisture content of building materials is described. The sensor was fabricated in Low Temperature Co-fired Ceramic (LTCC) technology, and consists of an inductor and an interdigitated capacitor. It is embedded in the test sample of a building material which has been set in pool water, so that changes in the moisture content of the specimen can be measured wirelessly tracking changes in the sensor resonant frequency. A clay brick and an autoclaved aerated concrete block were used for analysis and testing sensor's performances. Dielectric constant of water is much higher compared to the permittivity of test samples, and the increased moisture content in the samples increases the capacitance of the LC resonant sensor and consequently decreases the sensor resonant frequency. © 2011 Elsevier Ltd. All rights reserved.
Mitrovic J.,TEBA Steinenbronn |
Mitrovic J.,University of East Sarajevo
Chemical Engineering Science | Year: 2012
In 1871, Josef Stefan published a diffusion model that later became one of the fundamental models of transport phenomena, the Stefan-Maxwell (sometimes called the Maxwell-Stefan) diffusion relation. In his last paper on diffusion, which appeared in 1889, Stefan treated the evaporation-diffusion process in a vertical tube with a moving interface, and gave a complete analytical solution to this problem. This process - known as the Stefan diffusion problem - is frequently referred to in the literature. However, Stefan's own solution to this problem is not mentioned, and its existence seems to be unknown in scientific circles. The present note reproduces the Stefan's treatment of that evaporation-diffusion process. © 2012 Elsevier Ltd.