O. Adedokun, I. Bello, O. Adedeji, K. Talabi, O. Olatunji, R. Alasa
Aluminum Zinc co-doped Tin Oxide (AZSO) thin film was grown by sol-gel spin coating techniques onto a glass substrate using various doping concentrations (0, 2, 4, 6, and 8 wt%) and the effect of doping on each sample were studied using structural analysis; X-ray Diffraction (XRD) pattern, gravimetric method; thin film thickness and UV photo-spectrometer; optical properties. The results of the XRD were revealed that all the peaks have a tetragonal phase of SnO2, which were oriented at the 110, 101, and 211 planes. The film thickness was observed to vary with doping concentration. In the visible region, all the film samples were exhibited at average transmittance. The coefficient of absorption was gradually increased with an increase in photon energy at a certain level with a decrease in the absorption coefficient as the photon energy increases further. At 550-800 nm range of wavelength, a high extinction coefficient (k) was recorded and the refractive index curves show regular dispersion behavior. The optical conductivity of the films followed a similar pattern, which showed that conductivity increased to a peak at 3.60 eV. The energy bandgap of the film samples (AZSO1 - AZSO5) is 4.095 eV, 4.103 eV, 4.087 eV, 4.114 eV, and 4.106 eV, respectively. The studies show that the properties of Al-Zn co-doped SnO2 films can be explored for optoelectronic applications.
{"title":"Structural and optical characterization of aluminum zinc co-doped tin oxide grown by sol-gel spin coating techniques","authors":"O. Adedokun, I. Bello, O. Adedeji, K. Talabi, O. Olatunji, R. Alasa","doi":"10.2298/FUPCT2002109A","DOIUrl":"https://doi.org/10.2298/FUPCT2002109A","url":null,"abstract":"Aluminum Zinc co-doped Tin Oxide (AZSO) thin film was grown by sol-gel spin coating techniques onto a glass substrate using various doping concentrations (0, 2, 4, 6, and 8 wt%) and the effect of doping on each sample were studied using structural analysis; X-ray Diffraction (XRD) pattern, gravimetric method; thin film thickness and UV photo-spectrometer; optical properties. The results of the XRD were revealed that all the peaks have a tetragonal phase of SnO2, which were oriented at the 110, 101, and 211 planes. The film thickness was observed to vary with doping concentration. In the visible region, all the film samples were exhibited at average transmittance. The coefficient of absorption was gradually increased with an increase in photon energy at a certain level with a decrease in the absorption coefficient as the photon energy increases further. At 550-800 nm range of wavelength, a high extinction coefficient (k) was recorded and the refractive index curves show regular dispersion behavior. The optical conductivity of the films followed a similar pattern, which showed that conductivity increased to a peak at 3.60 eV. The energy bandgap of the film samples (AZSO1 - AZSO5) is 4.095 eV, 4.103 eV, 4.087 eV, 4.114 eV, and 4.106 eV, respectively. The studies show that the properties of Al-Zn co-doped SnO2 films can be explored for optoelectronic applications.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89140475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Great progress in the fight against malaria has been made in the last decade. Nevertheless, the development of resistance to almost all commonly used antimalarial drugs poses a major threat to the sustainability of this progress and highlights the need for the discovery of novel potent and inexpensive antimalarials to stay one step ahead. After the finding of ferrocene-containing analog of chloroquine - ferroquine, that can overcome Plasmodium resistance, a ?big-bang? in the metallocene antimalarials research has occurred. This review describes in detail the most recent advances in this important field of medicinal chemistry. Even though it is quite hard to beat ferroquine, it seems that this could be succeeded by suitable modifications in the structure of ferroquine, by the introduction of ? second metal center or through joining metallocenes with two or more proven antimalarial motifs into a single molecule.
{"title":"Recent updates in the development of mettallocenes with antimalarial activity","authors":"Jelena Aksic, Marija Gencic, N. Radulović","doi":"10.2298/FUPCT2001001A","DOIUrl":"https://doi.org/10.2298/FUPCT2001001A","url":null,"abstract":"Great progress in the fight against malaria has been made in the last decade. Nevertheless, the development of resistance to almost all commonly used antimalarial drugs poses a major threat to the sustainability of this progress and highlights the need for the discovery of novel potent and inexpensive antimalarials to stay one step ahead. After the finding of ferrocene-containing analog of chloroquine - ferroquine, that can overcome Plasmodium resistance, a ?big-bang? in the metallocene antimalarials research has occurred. This review describes in detail the most recent advances in this important field of medicinal chemistry. Even though it is quite hard to beat ferroquine, it seems that this could be succeeded by suitable modifications in the structure of ferroquine, by the introduction of ? second metal center or through joining metallocenes with two or more proven antimalarial motifs into a single molecule.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"124 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76797327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marija Dimitrijevic-Ciric, D. Gočanin, N. Konjik, V. Radovanovic
Theory founded on SO(2,3)* gauge symmetry. One significant feature of this approach is that gravitational field, given by the vierbein, becomes manifest only after a suitable gauge fixing and it is formally united with other gauge fields. Starting from a model of pure noncommutative gravity, we extend it by introducing fermions and Yang-Mills gauge field. Using the enveloping algebra approach and the Seiberg-Witten map we construct corresponding actions and expand them perturbatively in powers of the canonical noncommutativity parameter ???. Unlike in the case of pure noncommutative gravity, first non-vanishing noncommutative corrections are linear in the noncommutativity parameter and they describe the coupling of matter and gauge fields with gravity due to spacetime noncommutativity. This is augmented by the fact that some of these corrections pertain even in flat spacetime where they induce potentially observable noncommutative deformations. We discuss the effects of noncommutativity on electron?s dispersion relation in the presence of constant background magnetic field - Landau levels. Our results could be useful for further investigation of phenothe menological consequences of spacetime noncommutativity.
{"title":"Introducing matter fields in model of noncommutative gravity","authors":"Marija Dimitrijevic-Ciric, D. Gočanin, N. Konjik, V. Radovanovic","doi":"10.2298/fupct1901031d","DOIUrl":"https://doi.org/10.2298/fupct1901031d","url":null,"abstract":"Theory founded on SO(2,3)* gauge symmetry. One significant feature of this\u0000 approach is that gravitational field, given by the vierbein, becomes\u0000 manifest only after a suitable gauge fixing and it is formally united with\u0000 other gauge fields. Starting from a model of pure noncommutative gravity, we\u0000 extend it by introducing fermions and Yang-Mills gauge field. Using the\u0000 enveloping algebra approach and the Seiberg-Witten map we construct\u0000 corresponding actions and expand them perturbatively in powers of the\u0000 canonical noncommutativity parameter ???. Unlike in the case of pure\u0000 noncommutative gravity, first non-vanishing noncommutative corrections are\u0000 linear in the noncommutativity parameter and they describe the coupling of\u0000 matter and gauge fields with gravity due to spacetime noncommutativity. This\u0000 is augmented by the fact that some of these corrections pertain even in flat\u0000 spacetime where they induce potentially observable noncommutative\u0000 deformations. We discuss the effects of noncommutativity on electron?s\u0000 dispersion relation in the presence of constant background magnetic field -\u0000 Landau levels. Our results could be useful for further investigation of\u0000 phenothe menological consequences of spacetime noncommutativity.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90451169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We briefly review the conceptual basis of the recently introduced novel concept of the so-called Local Time in quantum theory. An emphasis is placed on certain cosmological aspects.
我们简要回顾了最近在量子理论中引入的所谓局部时间的新概念的概念基础。重点放在某些宇宙学方面。
{"title":"On the concept of local time","authors":"J. Jeknić-Dugić, M. Dugić, M. Arsenijević","doi":"10.2298/fupct1901053j","DOIUrl":"https://doi.org/10.2298/fupct1901053j","url":null,"abstract":"We briefly review the conceptual basis of the recently introduced novel\u0000 concept of the so-called Local Time in quantum theory. An emphasis is placed\u0000 on certain cosmological aspects.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87725842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Stojanovi'c, N. Bili'c, Dragoljub D. Dimitrijevi'c, G. Djordjevic, M. Milovsevi'c
In this paper, we study a tachyon cosmological model based on the dynamics of a 3-brane in the second Randall-Sundrum (RSII) model extended to include matter in the bulk. The presence of matter in the bulk changes the warp factor which leads to the modification of inflationary dynamics. The additional brane behaves effectively as a tachyon. We calculate numerically observation parameters of inflation: the scalar spectral index (ns) and the tensor-to-scalar ratio (r) for the exponential potential of the tachyon field.
{"title":"Inflationary RSII model with a matter in the bulk and exponential potential of tachyon field","authors":"M. Stojanovi'c, N. Bili'c, Dragoljub D. Dimitrijevi'c, G. Djordjevic, M. Milovsevi'c","doi":"10.2298/FUPCT1901079S","DOIUrl":"https://doi.org/10.2298/FUPCT1901079S","url":null,"abstract":"In this paper, we study a tachyon cosmological model based on the dynamics\u0000 of a 3-brane in the second Randall-Sundrum (RSII) model extended to include\u0000 matter in the bulk. The presence of matter in the bulk changes the warp\u0000 factor which leads to the modification of inflationary dynamics. The\u0000 additional brane behaves effectively as a tachyon. We calculate numerically\u0000 observation parameters of inflation: the scalar spectral index (ns) and the\u0000 tensor-to-scalar ratio (r) for the exponential potential of the tachyon\u0000 field.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"160 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73464983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Dimitrijevi'c, Dragoljub D. Dimitrijevi'c, G. Djordjevic, M. Milovsevi'c
In this paper, we continue the study of tachyon scalar field described by a Dirac-Born-Infeld (DBI) type action with constraints in the cosmological context. The proposed extension of the system introducing an auxiliary field in the minisuperspace framework is discussed. A new equivalent set of constraints is constructed, satisfying the usual regularity conditions.
{"title":"Constrained dynamics of tachyon field in FRWL spacetime","authors":"M. Dimitrijevi'c, Dragoljub D. Dimitrijevi'c, G. Djordjevic, M. Milovsevi'c","doi":"10.2298/FUPCT1901021D","DOIUrl":"https://doi.org/10.2298/FUPCT1901021D","url":null,"abstract":"In this paper, we continue the study of tachyon scalar field described by a\u0000 Dirac-Born-Infeld (DBI) type action with constraints in the cosmological\u0000 context. The proposed extension of the system introducing an auxiliary field\u0000 in the minisuperspace framework is discussed. A new equivalent set of\u0000 constraints is constructed, satisfying the usual regularity conditions.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"487 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78126225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Borka-Jovanovic, P. Jovanovi'c, D. Borka, S. Capozziello, S. Gravina, A. D'Addio
The aim of our investigation is to derive a particular theory among the class of scalar-tensor(ST) theories of gravity, and then to test it by studying kinematics and dynamics of S-stars around a supermassive black hole (BH) at Galactic Center (GC). We also discuss the Newtonian limit of this class of ST theories of gravity, as well as its parameters. We compare the observed orbit of S2 star with our simulated orbit which we obtained theoretically with the derived ST potential and constrained parameters. Using the obtained best-fit parameters we calculated orbital precession of S2 star in ST gravity and found that it has the same direction as in General Relativity (GR) but causes much larger pericenter shift.
{"title":"Constraining scalar-tensor gravity models by S2 star orbits around the galactic center","authors":"V. Borka-Jovanovic, P. Jovanovi'c, D. Borka, S. Capozziello, S. Gravina, A. D'Addio","doi":"10.2298/fupct1901011b","DOIUrl":"https://doi.org/10.2298/fupct1901011b","url":null,"abstract":"The aim of our investigation is to derive a particular theory among the class\u0000 of scalar-tensor(ST) theories of gravity, and then to test it by studying\u0000 kinematics and dynamics of S-stars around a supermassive black hole (BH) at\u0000 Galactic Center (GC). We also discuss the Newtonian limit of this class of\u0000 ST theories of gravity, as well as its parameters. We compare the observed\u0000 orbit of S2 star with our simulated orbit which we obtained theoretically\u0000 with the derived ST potential and constrained parameters. Using the obtained\u0000 best-fit parameters we calculated orbital precession of S2 star in ST\u0000 gravity and found that it has the same direction as in General Relativity\u0000 (GR) but causes much larger pericenter shift.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87500445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present work compares cross section sets for electron scattering from ground state helium and ground state water molecule, which are available at LXCat Morgan database and the new Quantemol-DB. These cross section sets are used as an input for numerical solving of Boltzmann equation by using electron Boltzmann solver BOLSIG+, in order to obtain transport coefficients, electron energy distribution function and rate coefficients for electron impact scattering processes. The calculated quantities are compared to examine the quality and completeness of the cross section sets provided by Quantemol database for modeling low-temperature plasmas and interpretation of experimental results.
{"title":"Comparisons of Quantemol and Morgan LXCat cross section sets for electron-neutral scattering and rate-coefficients: Helium and water","authors":"Ž. Mladenović, S. Gocić, Z. Petrović","doi":"10.2298/fupct1902145m","DOIUrl":"https://doi.org/10.2298/fupct1902145m","url":null,"abstract":"The present work compares cross section sets for electron scattering from ground state helium and ground state water molecule, which are available at LXCat Morgan database and the new Quantemol-DB. These cross section sets are used as an input for numerical solving of Boltzmann equation by using electron Boltzmann solver BOLSIG+, in order to obtain transport coefficients, electron energy distribution function and rate coefficients for electron impact scattering processes. The calculated quantities are compared to examine the quality and completeness of the cross section sets provided by Quantemol database for modeling low-temperature plasmas and interpretation of experimental results.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"181 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72796609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this article, we review two black hole solutions to the five-dimensional Lovelock gravity. These solutions are characterized by the non-vanishing torsion and the peculiar property that all their conserved charges vanish. The first solution is a spherically symmetric black hole with torsion, which also has zero entropy in the semiclassical approximation. The second solution is a black ring, which is the five-dimensional uplift of the BTZ black hole with torsion in three dimensions.
{"title":"Peculiar five-dimensional black holes","authors":"Dejan B. Simic","doi":"10.2298/fupct1901069s","DOIUrl":"https://doi.org/10.2298/fupct1901069s","url":null,"abstract":"In this article, we review two black hole solutions to the five-dimensional Lovelock gravity. These solutions are characterized by the non-vanishing torsion and the peculiar property that all their conserved charges vanish. The first solution is a spherically symmetric black hole with torsion, which also has zero entropy in the semiclassical approximation. The second solution is a black ring, which is the five-dimensional uplift of the BTZ black hole with torsion in three dimensions.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77599993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigate the weak probe pulse propagation through the atomic medium, in the presence of the strong control laser field, under the regime of the electromagnetically induced transparency (EIT). These fields couple to the medium by forming the 3-level ladder configuration. We focus on two distinct cases: closed system, which is a non-degenerate, and open system, where the middle level is 3-fold degenerate, and the additional levels are coupled to the other levels only via spontaneous emission. The spatio-temporal profile of the probe pulse envelope is obtained by using the formalism of Maxwell-Bloch equations with the help of the Fourier transform method. We study the influence of the control field Rabi frequency, the spectral half-width of the initial pulse and decay rates on the propagation of the probe pulse. Several important pulse parameters are also calculated and discussed. It is shown that the group velocity of light can be controlled in such a manner that one can switch from slow to fast light and vice versa when changing the control Rabi frequency and spectral pulse half-width. Moreover, the possibility of replacing the open with an effective closed system is also discussed.
{"title":"Slow and fast light propagation through ladder-type atomic media with degenerate energy levels","authors":"N. Filipović, V. Pavlovic, Ljiljana Stevanović","doi":"10.2298/fupct1902173f","DOIUrl":"https://doi.org/10.2298/fupct1902173f","url":null,"abstract":"We investigate the weak probe pulse propagation through the atomic medium, in the presence of the strong control laser field, under the regime of the electromagnetically induced transparency (EIT). These fields couple to the medium by forming the 3-level ladder configuration. We focus on two distinct cases: closed system, which is a non-degenerate, and open system, where the middle level is 3-fold degenerate, and the additional levels are coupled to the other levels only via spontaneous emission. The spatio-temporal profile of the probe pulse envelope is obtained by using the formalism of Maxwell-Bloch equations with the help of the Fourier transform method. We study the influence of the control field Rabi frequency, the spectral half-width of the initial pulse and decay rates on the propagation of the probe pulse. Several important pulse parameters are also calculated and discussed. It is shown that the group velocity of light can be controlled in such a manner that one can switch from slow to fast light and vice versa when changing the control Rabi frequency and spectral pulse half-width. Moreover, the possibility of replacing the open with an effective closed system is also discussed.","PeriodicalId":12248,"journal":{"name":"Facta Universitatis - Series: Physics, Chemistry and Technology","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81629741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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