S. Jacimovski - Academia.edu (original) (raw)

Papers by S. Jacimovski

ABSTRACT Difficulties connected to solving difference equations of hyperbolic type were analyzed ... more ABSTRACT Difficulties connected to solving difference equations of hyperbolic type were analyzed in this work and discussed in detail. The results are compared to those of the standard wave equation and certain similarities were established. The method of solving the equation is generalized by means of kernel expanded into separable polynomials. The analysis was inspired by some new ideas concerning quantization of time. Two examples are given: excitons and phonons in thin crystalline films. The advanced methodology of Green’s function method and the application of this new methodology resulted in a set of interesting conclusions concerning thin film properties. The significance of the obtained spatial dependence of exciton concentration was discussed and it was concluded, on the basis of the found spatial dependence of exciton concentration, that such boundary conditions of a thin molecular film which lead to high exciton concentrations can be determined. It was also concluded that thin films possess high superconductive properties, that physical characteristics of thin films are spatially dependent and that the spatial dependence can be the basis for widening the field of application of nanostructures.

Journal of Computational and Theoretical Nanoscience, 2007

Original scientific paper The uneven development and achieved degree of economy have negative con... more Original scientific paper The uneven development and achieved degree of economy have negative consequences on the quality of the environment in Smederevo. The most endangered area is the industrial area of "Zelezara Smederevo" which directly threatens the city of Smederevo and a few settlements nearby, like Radinac, Ralja and Vranovo. Using a mathematical pattern the maximum low concentration of SO2 exhausted from the blast furnace of "Zelezara Smederevo" was calculated. The data from health statistics about prescribed medicine, the structure of diseases and the current information about the degree of endangered environment were used to illustrate the cause and effect relation between health condition and the influence of certain pollutants existing in the environment.

ЖУРНАЛ ЗА БЕЗБЈЕДНОСТ И КРИМИНАЛИСТИКУ, 2019

In the late twentieth century, human race entered the era ofinformation technology (IT). The IT i... more In the late twentieth century, human race entered the era ofinformation technology (IT). The IT industry, which deals with the production,processing, storage and transmission of information, has become an integralpart of the global economic system, a completely independent and significantsector of the economy. The dependence of the modern society on informationtechnologies is so great that omissions in information systems may lead tosignificant incidents. Telecommunications are the key information technologyindustry. However, information is very susceptible to various types of abuseduring transmission. The units for data storage and processing can bephysically protected from anyone wishing harm, but this does not hold truefor the communication lines that span hundreds or thousands of kilometersand are virtually impossible to protect. Therefore, the problem of informationprotection in the field of telecommunications is highly significant. Cryptology,particularly cryptography, deals w...

Zastita materijala, 2018

Multilayer composite structures of electrodeposited Ni films on polycrystalline copper substrates... more Multilayer composite structures of electrodeposited Ni films on polycrystalline copper substrates were fabricated with the assistance of ultrasonic agitation. Alternate ordinary and ultrasonicassisted electrodeposition of Ni layers allowed the formation of laminated films. The adhesion and hardness properties were characterized using bidirectional bending test and Vickers microhardness test with different loads. Dependence of composite microhardness and film adhesion on layer thickness was investigated. It was confirmed that densified parallel interfaces give rise to high hardness and strength of composites. Model of Korsunsky was chosen and applied to experimental data for obtaining the film hardness and model of Chen-Gao was applied for the adhesion evaluation. Compared with the conventional electrodeposited Ni films, the mechanical properties of the ultrasonic-assisted multilayer Ni films are improved. The microhardness and adhesion of the films are enhanced by introduction of ultrasound and by reducing the layer thickness in the film.

Physica E: Low-dimensional Systems and Nanostructures, 2005

The Green&#39;s function technique, suitable for analyses of spatially deformed structure... more The Green&#39;s function technique, suitable for analyses of spatially deformed structures, is developed in this paper and applied to phonon system. The thermodynamic and kinetic phonon properties of cylindrical quantum dots are analysed using a developed method. As a consequence of the applied new method the configurational dependence of diffusion coefficient and dot&#39;s density were included into calculations. Maximum of

Macedonia and the Balkans, a hundred years after the World War I : security and euro-atlantic int... more Macedonia and the Balkans, a hundred years after the World War I : security and euro-atlantic integrations. Vol. 2 / International scientific conference, 3-5 June 2014, Ohrid, Republic of Macedonia

Acta Polytechnica Hungarica, 2021

The basis for proactive maintenance in thermal power plants, is the analysis of the root cause of... more The basis for proactive maintenance in thermal power plants, is the analysis of the root cause of the failure, i.e. the determination of mechanism and cause of failure occurrence from the thermal power plant system. The root causes of system failures can be eliminated in this way, and the causes of failures can gradually be eliminated using an engineering approach from any assembly of device or machine. Successful proactive maintenance programs would gradually, over time, eliminate problems of the device by project-engineering solutions, which, as a consequence, would have a significantly longer device life cycle, reduced downtime and increase production capacity.

Reviews in Theoretical Science, 2016

Application of nano-structures requires a knowledge of their fundamental physical (mechanical, el... more Application of nano-structures requires a knowledge of their fundamental physical (mechanical, electromagnetic, optical, etc.) characteristics. Thermodynamic properties associated with phonon displacements through the nano-samples are particularly interesting. Independent of the type of lattices, the thermodynamics of their subsystems (electrons, excitons, spin waves, etc.) is determined when the subsystem is in thermodynamic equilibrium with phonons. Phonons are collective mechanical oscillations of molecules or atoms and represent the most important system of excitations. Besides, the acoustical characteristics as well as conductive and superconductive properties etc. could not be realistically explained without phonons. All quoted is well known and all applications of phonons in bulk structures have been intensively exploited for more than a century. The fact which must be especially pointed out is that the role of phonons in nanostructures is much more impressive than in bulk structures. The main fact concerning phonon properties in nanostructures is the absence of the so-called acoustic phonons, i.e., phonons whose energy tends to zero when phonon momentum tends to zero. For the exciting of phonons in nanostructures activation energy different from zero is necessary. These unexpected characteristics require revision of all conclusions obtained by bulk theories of phonons. Therefore, the contribution of phonon subsystems to thermodynamic and energy transfering analysis is the first step in a research of nanostructure properties. This paper describes a major aspect of the effort to understand nanostructures, namely the study of phonons and phonon-mediated effects in structures with nanoscale dimensional confinement in one or more spatial dimensions. During the last two decades, there has been a steady effort to understand the optical and acoustic phonons in nanostructures such as the superlattice, quantum wires, nanotubes and quantum dots. The central theme of this paper is the description of the acoustic phonons of the optical type in these nanostructures. As a preliminary to describing the dispersion relations and mode structures for phonons in nanostructures, phonon amplitudes are quantized in terms of the harmonic oscillator approximation, and anharmonic effects leading to phonon decay are described in terms of the dominant phonon decay channels. These elastic and discontinued models are applied to describe the deformation potential and interactions in a variety of nanostructures. Dependence of energy on the wave vector is highly nonlinear and linear approximation of the laws of dispersion of phonons in small size nanostructures makes no sense. Changing the phonon dispersion law due to confinement severely affects the kinetic effects conditioned by the interaction of acoustic phonons with electrons, dotted defects, phonon-phonon interactions. Managing transport properties of acoustic phonons through the modification of their energy spectrum in nanostructures was named phonon engineering. In this paper we will try to observe the difference between the characteristics of different nano-crystalline structures: ultrathin films, composite films, i.e., superlattices, nanorods and quantum dots, we were interested in whether the quantum size effects (quantum confinement), quantum (de) coherence and influence of boundary conditions, strengthen or weaken in nanosamples. Finally, this paper describes how the dimensional confinement of phonons in nanostructures leads to modifications in the electronic, optical, acoustic, superconducting and thermodynamic properties of quantum. Thermal properties of nanostructures have recently attracted a lot of attention. The influence of size effects on thermal conductivity is becoming extremely important for device design and reliability. The problem of thermal management is even more severe for photonic devices such as vertical cavity surface emitting lasers. On the other hand, to improve performance of thermoelectrics, one needs to achieve low thermal conductivity. These are two contradictory demands, but both can be approached with appropriate modification of phonon modes, e.g., phonon engineering. On the basis of the calculated dispersion law and distribution of phonon states in nanoscopis crystals, free energy and entropy will be calculated. Internal energy as well as heat capacitance will also be analyzed. Low-temperature behavior of these quantities will be compared to the corresponding ones of bulk-structures. It was shown that heat capacitances of nano-layered structures in low-temperature region were higher than the same quantities of the corresponding bulk sample. In the middle and the highest temperature region, temperature behavior was inverse: heat capacitance of layered structures was lower than of the corresponding bulk ones. The consequences were discussed with relation to the better superconductive properties of nanomaterials

Journal of Computational and Theoretical Nanoscience, 2008

The superconductivity properties of cylinder with nano cross-section are investigated. In the nea... more The superconductivity properties of cylinder with nano cross-section are investigated. In the nearest neighbours approximation, electron Hamiltonian of cylinder decays onto two independent Hamiltonians. One corresponds to electrons which propagate along chains parallel to the axis of cylinder. Second correspond to electrons moving in discs. The electron-phonon interaction Hamiltonians are found and superconductive properties were examined in the frames of BCS approach. It was shown that superconductive temperature in chains is several Kelvins, while in discs it can be higher for two orders of magnitude. It is also shown that magnetic field produced by electron currents in discs is of the order of thousand Tesla, i.e., extremely high.

Acta Physica Polonica A, 2011

In this paper 1D crystal lattice is analyzed within harmonic approximation, with one atom per ele... more In this paper 1D crystal lattice is analyzed within harmonic approximation, with one atom per elementary cell and nearest neighbor interaction included. For this type of crystal lattice dispersion relations are well known. Thermodynamic functions (specific heat and phonon thermal conductivity) are calculated via phonon density of states given in exact form. Thermodynamic variables are calculated for a whole temperature range. In limiting cases of low and high temperatures these thermodynamic variables can be found in analytic forms. For thermal conductivity the results of Callaway model for exact phonon density of states are compared with the results of Callaway model for Debye approximation of phonon density of states.

Nauka, bezbednost, policija, 2015

Tehnicki vjesnik - Technical Gazette, 2017

Original scientific paper This study analyses the condition and quality of the environment which ... more Original scientific paper This study analyses the condition and quality of the environment which is endangered by typical pollutants present in urban areas. The main sources of air pollution are power sector (mostly power plants), transport sector (motor vehicles) and industrial plants. Among these substances the most common and most harmful to human health and biological systems is sulphur dioxide. The effects of sulphur dioxide are sensed very easily, most people experience the symptoms after 10÷15 minutes. Therefore the concentration of sulphur dioxide in the air is taken as a referent parameter for the assessment of air quality and evaluation of air pollution. In this study the metallurgy plant which processes 1000 tons of copper-chalcopyrite ore daily is analysed as the illustrative example. By using Gaussian mathematical model the distribution of ground concentration of sulphur dioxide is analysed for the different heights of chimneys and different emissions in stable and unstable atmospheric conditions. Calculation of distribution and spreading of sulphur dioxide covers the period of 24 hours after the release into the atmosphere. The results are compared with the legally permissible limit value concentrations.

Acta Physica Polonica A, 2018

In this paper, we investigated the influence of size effect on thermodynamic properties of ultra-... more In this paper, we investigated the influence of size effect on thermodynamic properties of ultra-narrow wires with a simple cubic lattice, by means of two-time dependent Green functions method, adjusted to confined crystalline structures. Poles of Green functions, which defining phonon spectra, are found by solving the secular equation. For different boundary parameters, this problem is presented graphically. The temperature behavior of ultra-narrow wire thermal capacitance is compared to that of bulk structures. It turned out that in low-temperature region thermal capacitance of the ultra-narrow wire is notably lower than in the corresponding bulk sample. How this fact reflects the thermal, conducting and superconducting properties of materials, is discussed in the conclusion.

Zbornik radova - Geografski fakultet Univerziteta u Beogradu, 2015

Извод: У раду су обрађене карактеристике дубоке издани Смедеревског Подунавља које припадају мора... more Извод: У раду су обрађене карактеристике дубоке издани Смедеревског Подунавља које припадају моравској хидрогеолошкој области. Хидрогеолошки комплекс Смедеревског Подунавља развијен је у седиментима неогене старости. Запажено је наизменично смењивање хидрогеолошких колектора, састављених од песковитих и шљунковитих седимената и хидрогеолошких изолатора који чине глиновите творевине. Анализом досадашњих геолошких истраживања, геофизичких испитивања и бушења за потребе водоснабдевања покушали смо да представимо просторни положај колектора и збијених издани формираних у њима. Из приказа положаја колектора и издашности дубоке издани проистиче и оцена могућности коришћења воде под притиском. Издан под притиском је субартеског и артеског карактера са нивоом подземних вода од +0,6 до-90 m. Експлоатациона издашност објеката се креће и преко 5 l/s. Хемијске анализе подземних вода из понтијских водоносних пескова по Алекину припадају хидрокарбонатно-земноалкалним типовима воде, чија минерализација се креће око 0,5 g/l што значи да су умерено тврде и могу да се користе за пиће. Воде панонских слојева припадају меким водама, а у дубљим деловима постоји могућност повишене минерализације.

$Research paper thumbnail of Successive absorption and refraction of ultrathin molecular nano-films$

Zastita materijala, 2014

Sukcesivna apsorpcija i refrakcija kod ultratankih molekulskih nanofilmova U radu su na osnovu fo... more Sukcesivna apsorpcija i refrakcija kod ultratankih molekulskih nanofilmova U radu su na osnovu formiranog modela nanofilm kristalnih struktura teorijski istraživane i izučavane promjene optičkih osobina usled prisustva granica kod simetričnih ultratankih filmova. Ispitani su uticaji pet graničnih parametara na pojavu lokalizovanih eksitonskih stanja, kao i na njihovu povezanost sa efektima diskretizacije i selekcije rezonantne apsorpcije prisutnog elektromagnetnog zračenja. Analitičko-numeričkim proračunom, nađen je energetski spektar eksitona i njihova prostorna distribucija duž ose ograničenja (po slojevima). Određena je relativna permitivnost ovih ultratankih dielektričnih filmova i analiziran uticaj graničnih parametara na pojavu diskretne, tj. selektivne apsorpcije.

STEVO K. JACIMOVSKI, VJEKOSLAV D. SAJFERT, DEJAN I. RAKOVIC, JOVAN P. SETRAJCIC Academy of Crimin... more STEVO K. JACIMOVSKI, VJEKOSLAV D. SAJFERT, DEJAN I. RAKOVIC, JOVAN P. SETRAJCIC Academy of Criminalistic and Police Studies, Belgrade, Serbia University of Novi Sad, Technical Faculty ,,M. Pupin”, Zrenjanin, Vojvodina – Serbia University of Belgrade, Faculty of Electrical Engineering, Serbia University of Novi Sad, Faculty of Sciences, Department of Physics, Vojvodina – Serbia Academy of Sciences and Arts of the Republic of Srpska, Banja Luka, B&H

Acta Physica Polonica A, 2010

In the nanocylinder, a cutoff from the molecular crystal, dielectric permeability tensor is inves... more In the nanocylinder, a cutoff from the molecular crystal, dielectric permeability tensor is investigated. Excitons in the nanocylinder arise due to the exciting of the electron subsystem of the molecule. In evaluation of dielectric permeability Dzhyaloshinskii-Pitaevskii approach is used, connected with retarded and advanced exciton Green's functions and correct use of Paulion Green's function. It turned out that refraction and absorption indices depend on configuration coordinates, having maximal values at boundary cross-sections and minimal value at central cross-section of the nanocylinder broken symmetry structure. Although it was expected that boundary conditions make higher refractive and absorptive characteristics of the nanocylinder, this appeared not to be possible because Paulion Green's function is not proportional to the exciton concentration.

BioMed Research International, 2014

In the context of the macroscopic quantum phenomena of the second kind, we hereby seek for a solu... more In the context of the macroscopic quantum phenomena of the second kind, we hereby seek for a solution-in-principle of the long standing problem of the polymer folding, which was considered by Levinthal as (semi)classically intractable. To illuminate it, we applied quantum-chemical and quantum decoherence approaches to conformational transitions. Our analyses imply the existence of novel macroscopic quantum biomolecular phenomena, with biomolecular chain folding in an open environment considered as a subtle interplay between energy and conformation eigenstates of this biomolecule, governed by quantum-chemical and quantum decoherence laws. On the other hand, within an open biological cell, a system of all identical (noninteracting and dynamically noncoupled) biomolecular proteins might be considered as corresponding spatial quantum ensemble of these identical biomolecular processors, providing spatially distributed quantum solution to a single corresponding biomolecular chain folding,...