Prikazano Природно-математички факултет za naslov
Prikaz rezultata 234-253 od 269
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Synthesis and antioxidant activity of a new 4-aminocoumarin derivative
Synthesis, spectral characterization, and evaluation of in vitro antioxidant activity of a new coumarin derivative, 4- ((1,3,4-thiadiazol-2-yl)amino)-3-nitro-2H-chromene-2-one, are described. The synthesis of the new product ... -
Synthesis and characterization of pH-sensitive Saccharide modified polyurethane hydrogels – Effect of polyol, crosslinker and acid chain extender
(Univerzitet u Nišu - Tehnološki fakultet, Leskovac, 2021-07-10)Biodegradable polyurethanes can be the basis for drug delivery systems that are sensitive to external changes. pH-sensitive polyurethanes (PUs) have been used successfully as intravaginal rings and specific drug delivery ... -
Synthesis and characterization of quercetin-conjugated gold nanoparticles
(Society of Physical Chemists of Serbia, 2018-09-28)Gold nanoparticles and quercetin-conjugated gold nanoparticles complex were synthesized using trisodium citrate as reducing agent. Both kinds of nanoparticles were characterized using spectrophotometry, dynamic light ... -
Synthesis and complete NMR spectral assignments of new benzylamino coumarin derivative
This research involves the reaction of 4-chloro-3-nitrocoumarin and (4-methoxyphenyl)methanamine, whereby a novel coumarin derivative 4-[(4-methoxybenzyl) amino]-3-nitro-2H-chromen-2-one was obtained in good yield. The ... -
Synthesis and spectral characterization of asymmetric azines containing a coumarin moiety: The discovery of new antimicrobial and antioxidant agents
(2018-10-25)Nine unsymmetrical azines containing a coumarin moiety were prepared by the reaction of the hydrazone of 4-hydroxy-3-acetylcoumarin with differently substituted aromatic aldehydes. The azines were fully spectrally ... -
Synthesis of Zinc Doped Phosphate Tungsten Bronzes and its Redox Activity in Aqueous Solution of LiNO3
Phosphate tungsten bronzes (WPB) have been intensively investigated for many applications due to their interesting chemical, optical, electrical, and mechanical properties. Their most known usages are as a pigment in ... -
Synthesis, characterization and biological study of new dinuclear zinc(II) and nickel(II) octaaza macrocyclic complexes
Two new nitrato complexes of zinc and nickel with 1,4,8,11-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc), have been synthesized and characterized. The IR spectral peaks showed that the coordinated and ... -
Synthesis, characterization, hydrolytic, and thermal stability of urea–formaldehyde composites based on modified montmorillonite K10
(Springer, 2022-02-11)In this study, the thermal and hydrolytic properties of composite systems based on the urea–formaldehyde resin (UF) and eco-friendly montmorillonite (K10) as formaldehyde (FA) scavenger were examined. UF resin with molar ... -
Synthesis, complete assignment of 1H- and 13C-NMR spectra and antioxidant activity of new azine derivative bearing coumarin moiety
In this research, the synthesis of a new azine derivative with coumarin moiety was performed in three reaction steps, starting from 4-hydroxycoumarin. The first step in synthesis was the acetylation of 4-hydroxycoumarin ... -
System Maintenance Decision Making Based on Repair Rate Statistics
This paper presents a novel approach for estimation of repair rate in an observed system comprised of two or more components. The presented approach is based on calculation of probability density function of maximal and ... -
System performances of sc reception in asymmetric multipath fading environments
(2019-06-23)The paper takes into consideration dual-branch selection combining (SC) diversity reception technique in the presence of dissimilar fading at their branches. We efficiently obtained first and second order closed form ... -
Ternary NR/BR/SBR rubber blend nanocomposites
(SAGE, 2018-02-24)The goal of this work was to synthesize and characterize ternary rubber blends based on polyisoprene (natural rubber (NR)), polybutadiene rubber (BR), and styrene–butadiene rubber (SBR) (NR/BR/SBR = 25/25/50) reinforced ... -
Theoretical investigation of bandwidth of multimode step-index silica photonic crystal fibers
(MDPI, 2022-03-23)Solving the time-dependent power flow equation (PFE) provides a useful method to study the transmission bandwidth of step-index silica photonic crystal fibers (SI SPCFs). The transmission bandwidth of these kinds of ... -
Theoretical investigation of the capacity of space division multiplexing with step-index air-clad silica optical fibers
(MDPI, 2022-02-23)We studied the effect of mode coupling on the space division multiplexing (SDM) capabilities of multimode step-index (SI) air-clad silica optical fibers by numerically solving the power flow equation. Mode coupling ... -
Theoretical Investigation of the Influence of Wavelength on the Bandwidth in Multimode W-Type Plastic Optical Fibers with Graded-Index Core Distribution
(MDPI, 2021-11-17)The bandwidth of multimode W-type plastic optical fibers (POFs) with graded-index (GI) core distribution is investigated by solving the time-dependent power flow equation. The multimode W-type GI POF is designed from a ... -
Thermal behavior of gamma-irradiated urea-formaldehyde composites based on the differently activated montmorillonite K10
(Springer, 2022-07-09)This work investigated the thermal characteristics of irradiated composite materials formulated on the urea–formaldehyde resin (UF) and differently activated montmorillonite (K10). UF resin with molar ratio F:U = 0.8 was ... -
Thermolysis prepared Co3O4 carbon paste electrode decorated with single wall nanotubes as voltammetric sensor for determination of antioxidant α-lipoic acid
The novel carbon material modified with Co3O4 particles, prepared by calcination and mixed with single wall carbon nanotubes, was characterized and used for sensing of prominent antioxidant α- lipoic acid (LA). The new ... -
The total curvature of knots under second-order infinitesimal bending
(World Scientific Publishing Co. Pte. Ltd., 2019-01-03)In this paper, we consider infinitesimal bending of the second-order of curves and knots. The total curvature of the knot during the second-order infinitesimal bending is discussed and expressions for the first and the ... -
Total Normalcy of Knots
(Faculty of Sciences and Mathematics, University of Niš, 2019-01-01)In this paper we consider first order infinitesimal bending of curves and knots. The total normalcy of the knot during the first order infinitesimal bending is discussed and expressions for the first variation of the total ... -
THE TOTAL TORSION OF KNOTS UNDER SECOND ORDER INFINITESIMAL BENDING
(University of Belgrade - School of Electrical Engineering, 2021-10-26)In this paper we consider infinitesimal bending of the second order of curves and knots. The total torsion of the knot during the second order infinitesimal bending is discussed and expressions for the first and the ...