OALib Journal期刊

ISSN: 2333-9721




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2013 ( 66 )


匹配条件: “Marija CAKIC” ,找到相关结果约1040条。
Marija CAKIC
Journal of Special Education and Rehabilitation , 2013,
The Hyperspherical Functions of a Derivative
Nenad Cakic,Du?ko Letic,Branko Davidovic
Abstract and Applied Analysis , 2010, DOI: 10.1155/2010/364292
Abstract: We present the results of theoretical research of the generalized hypersherical function (HS) by generalizing two known functions related to the sphere hypersurface and hypervolume and the recurrent relation between them. By introducing two-dimensional degrees of freedom and (and the third, radius ), we develop the derivative functions for all three arguments and the possibilities of their use. The symbolical evolution, numerical experiment, and graphical presentation of functions are realized using the Mathcad Professional and Mathematica softwares. 1. Introduction The hyperspherical function (HS) is a hypothetical function related to multidimensional space and generalization of the sphere geometry. This function is primarily formed on the basis of the interpolating power of the gamma function. It belongs to the group of special functions, so its testing, besides gamma, is performed on the basis of the related functions, such as -gamma, -psi, -beta, erf, and so forth. Its most significant value is in its generalizing from discrete to continuous [1]. In addition, we move from the field of natural integers of the geometry sphere dimensions—degrees of freedom, to the set of real and nonintegral values, thus, we obtain the prerequisites for a more concise analysis of this function. In this paper the analysis is focused on the infinitesimal calculus application of the hyperspherical function that is given in its generalized form. For the development of hyperspherical and other functions of the multidimensional objects, see: Bishop and Whitlock [2], Collins [3], Conway [4], Dodd and Coll [5], Hinton [6], Hocking and Young [1], Manning [7], Maunder [8], Neville [9], Rohrmann and Santos [10], Rucker [11], Maeda et al. [12], Sloane [13], Sommerville [14], Weels [15], and others; see [16–22]. Nowadays, the research of the hypersperical functions is represented both in Euclid’s and Riemann’s geometry and topology (Riemann’s and Poincare’s sphere, multidimensional potentials, theory of fluids, nuclear (atomic) physics, hyperspherical black holes, etc.) 2. The Hyperspherical Functions of a Derivative 2.1. The Hyperspherical Funcional Matrix The former results, as it is known, [5, 23], give the functions of the hyperspherical surface ( ) and volume ( ) therefore, we have In general, we have Thus, we give the definition of the hyperspherical function [24]. Definition 2.1. The hyperspherical function with two degrees of freedom and is defined as This is a function of three variables and two degrees of freedom and and the radius of the hypersphere . In real spherical
The Relational Translators of the Hyperspherical Functional Matrix
Letic Dusko,Cakic Nenad,Davidovic Branko
Advances in Difference Equations , 2010,
Abstract: We present the results of theoretical researches of the developed hyperspherical function for the appropriate functional matrix, generalized on the basis of two degrees of freedom, and , and the radius . The precise analysis of the hyperspherical matrix for the field of natural numbers, more specifically the degrees of freedom, leads to forming special translators that connect functions of some hyperspherical and spherical entities, such as point, diameter, circle, cycle, sphere, and solid sphere
The Relational Translators of the Hyperspherical Functional Matrix
Dusko Letic,Nenad Cakic,Branko Davidovic
Advances in Difference Equations , 2010, DOI: 10.1155/2010/261290
Fast Fourier Transform IR Characterization of Epoxy GY Systems Crosslinked with Aliphatic and Cycloaliphatic EH Polyamine Adducts
Goran Nikolic,Sasa Zlatkovic,Milorad Cakic,Suzana Cakic,Caslav Lacnjevac,Zoran Rajic
Sensors , 2010, DOI: 10.3390/s100100684
Abstract: The use of fast FT-IR spectroscopy as a sensitive method to estimate a change of the crosslinking kinetics of epoxy resin with polyamine adducts is described in this study. A new epoxy formulation based on the use of polyamine adducts as the hardeners was analyzed. Crosslinking reactions of the different stoichiometric mixtures of the unmodified GY250 epoxy resin with the aliphatic EH606 and the cycloaliphatic EH637 polyamine adducts were studied using mid FT-IR spectroscopic techniques. As the crosslinking proceeded, the primary amine groups in polyamine adduct are converted to secondary and the tertiary amines. The decrease in the IR band intensity of epoxy groups at about 915 cm-1, as well as at about 3,056 cm-1, was observed due to process. Mid IR spectral analysis was used to calculate the content of the epoxy groups as a function of crosslinking time and the crosslinking degree of resin. The amount of all the epoxy species was estimated from IR spectra to changes during the crosslinking kinetics of epichlorhydrin.
Effect of explant type, medium and soil mixture content on Dianthus deltoides L. rooting and acclimatization
Markovi? Marija,Popovi? Marija
Glasnik ?umarskog Fakulteta , 2012, DOI: 10.2298/gsf1205117m
Abstract: The possibility of developing roots and shoots on Dianthus deltoides nodal and apical cuttings on rooting media was investigated in vitro conditions. The explants developed roots and shoots successfully, and the best results were achieved on MS medium without plant hormones. Number of roots per shoot, length of roots and ramification of roots were not significantly dependent on the medium (NAA-naphthaleneacetic acid concentration), or on the type of explant used (nodal or apical cuttings). The acclimatization rate of microplants was influenced by root numbers and ramification. The transfer to soil was successful, maximum survival rates (96%) were achieved on peat - sand (4:1) mixture.
Floristic analysis of perennial species on flowerbeds in Belgrade with special attention on invasiveness of the recorded species
Popovi? Marija,Markovi? Marija
Glasnik ?umarskog Fakulteta , 2012, DOI: 10.2298/gsf1206169p
Abstract: Urban areas are among the most important centres of invasive plant species distribution due to their richness in alien species. Because of that, a detailed floristic analysis of perennial flowerbeds was conducted in the central parks of Belgrade. A total of 53 perennial species were found, of which 55% were the alien species planted on 75% of the research area. Among them, two species (Aster novi belgii and Solidago canadensis) are invasive and six species are potentially invasive in Serbia. These are planted on 5% and 20% of the flowerbeds, respectively. We can conclude that both the experts and institutions should be informed about the invasive species and potential damages. In the meantime, planting of native decorative species should be encouraged, since they will not pose a threat to natural habitats. Also, detailed research should be conducted in order to eradicate invasive and potentially invasive species from the surfaces around the research area.
Synthesis and characterization of Co(II), Ni(II), Cu(II) and Zn(II) complexes with 3-salicylidenehydrazono-2-indolinone
Journal of the Serbian Chemical Society , 2003,
Abstract: Complexes of Co(II), Ni(II), Cu(II) and Zn(II) with 3-salicylidenehydrazono-2-indolinone were prepared. Their structure was established to be [MLCl].Cl by using elemental analysis and molar conductivity, as well as AA, FTIR, UV/VIS and 1H-NMR spectroscopic methods. The spectral studies indicated a square-planar geometry for the Ni(II) and Cu(II) complexes and a tetrahedral one for the Co(II) and Zn(II) complexes. The complexes were tested for antibacterial activity against Staphylococcus aureus, Enterococcus D, Proteus mirabilis, Escherichia coli, Bacillus anthracis, Pseudomonas aeruginosa and Candida albicans.
Thermo-oxidative stability of waterborne polyurethanes with catalysts of different selectivity evaluated by non-isothermal thermogravimetry
Journal of the Serbian Chemical Society , 2007,
Abstract: Thermogravimetry was used for the evaluation of the thermo-oxidative stability of waterborne polyurethanes (wbPUR) containing catalysts of different selectivity. From Arrhenius plots, activation energies of between 50 and 120 kJ mol-1 for wbPUR were determined, depending on the temperature interval, selectivity of the catalyst and degree of degradation. Waterborne polyurethanes without catalyst showed lower thermal stability than waterborne polyurethanes with catalysts of different selectivity. Non-isothermal thermogravimetry indicated the presence of different degradation processes and enabled the kinetics parameters at higher degrees of degradation to be evaluated.
Preconcentration method for trace metals in natural waters using 4-morpholine dithiocarbamate
Journal of the Serbian Chemical Society , 2002,
Abstract: The optimum conditions were found for the preconcentration of trace metals in natural waters and model samples with standard metals concentrations by using 4-morpholinedithiocarbamate. The formed complexes were extracted with chloroform. Different methods for recovering the metals from the organic solvent were studied and compared before AAS metal analysis. The developed preconcentration method was successfully applied to the determination of trace metals concentrations in water samples from the Barje lake (Leskovac, Yugoslavia).

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