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71.
Aart Blokhuis Győrgy Kiss István Kovács Aleksander Malnič Dragan Marušič János Ruff 《组合设计杂志》2007,15(6):491-501
Semiovals which are contained in the union of three concurrent lines are studied. The notion of a strong semioval is introduced, and a complete classification of these objects in PG(2,p) and PG(2,p2), p an odd prime, is given. © 2007 Wiley Periodicals, Inc. J Combin Designs 15: 491–501, 2007 相似文献
72.
73.
Ecaterina Stela Dragan Marcela Mihai J. Schauer Luminita Ghimici 《Journal of polymer science. Part A, Polymer chemistry》2005,43(18):4161-4171
Polyacrylonitrile (PAN) composite membranes with surface properties designed by either a chemical modification with ethylenediamine (EDA), or layer‐by‐layer (LbL) polyelectrolyte adsorption were investigated in this paper. Fourier‐transformed infrared (FTIR) spectroscopy and streaming potential measurements showed that the first step of the reaction with EDA in gas phase was the formation of ammonium salts with the reactive carboxylic groups present on the surface of the starting membrane. Part of the ammonium carboxylate groups was transformed in secondary amide linkages by a heat‐induced reaction. Poly(sodium styrenesulfonate) (NaPSS) and a polycation containing about 95 mol % of N,N‐dimethyl‐2‐hydroxypropyleneammonium chloride units in the backbone (PCA5) were used as opposite polyions in the LbL film construction. The adsorbed polyion amount per every layer was controlled by the nature and concentration of the supporting electrolyte in polyelectrolyte deposition solution (NaBr and KBr). An almost linear increase of the adsorbed polyion amount versus the layer pair number was observed. The swelling degree (SD) in pure alcohols of the LbL‐modified PAN composite membrane decreased with the increase of the solvent polarity and with the decrease of the pore volume by pore filling with polyelectrolyte complex multilayer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4161–4171, 2005 相似文献
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75.
Dragan Dimitrovski Dragana Radosavljevi? Miloje Rajovi? Rade Stoiljkovi? 《Acta Mathematica Hungarica》2011,132(1-2):15-26
It is shown that Sturm theorems, formulated in the 1830??s ([1], [2], [3] and [4]) and valid for second order linear homogeneous differential equation L(y)??y??+a(x)y??+b(x)y=0, could as well be formulated for the class of nonhomogeneous linear differential equations L(y)=f(x). Criteria for the existence of oscillatory solutions of nonhomogeneous equations, as well as more exact locations of the zeros are given. 相似文献
76.
Snežana Č. Živković-Zlatanović Dragan S. Djordjević Robin E. Harte 《Integral Equations and Operator Theory》2011,69(3):347-363
We consider left and right Browder operators, left and right Fredholm operators, spectra related with these operators, and
various operator quantities. 相似文献
77.
Mihajilov-Krstev T Kitić D Radnović D Ristić M Mihajlović-Ukropina M Zlatković B 《Natural product communications》2011,6(8):1167-1172
Plant species Satureja kitaibelii Wierzb. ex Heuff. is used as a spice and as a natural preservative for food and herbal tea, owing to its characteristic scent and flavor as well as high antimicrobial activity. In the present study, the antimicrobial activity of isolated essential oil of S. kitaibelii was tested against a panel of 30 pathogenic microorganisms (foodborne microbes, selected multiresistant bacterial isolates from the patient wounds and dermatophyte isolates). Limonene (15.54%), p-cymene (9.99%), and borneol (8.91%) appeared as the main components in 44 identified compounds representing 98.44% of the oil. Essential oil of S. kitaibelii showed significant activity against a wide spectrum of foodborne microbes (MIC=0.18-25.5 microg mL(-1)) and multiresistant bacterial isolates (MIC=6.25-50.0 microg mL(-1)), as well as against dermatophyte strains (MIC=12.5-50.0 microg mL(-1)). These results demonstrate that S. kitaibelii essential oil could be used as a natural potential antimicrobial agent against pathogenic strains in the treatment of foodborne disease, wound and skin infections. 相似文献
78.
Jasmina M. Dimitrić Marković Dragan S. Veselinović Jelisaveta M. Baranac Tanja P. Brdarić 《光谱学快报》2013,46(3):104-115
Complexation of aluminum (III) with cyanidin, a natural anthocyanidin molecule, has been investigated in methanol and buffered solutions of pH 3.0 and 4.0. Electronic absorption spectroscopy was performed to characterize the stoichiometry and stability of the complexes formed. In investigated solvents, aluminum bonded moderately to cyanidin requiring large mole ratios of the components (up to 200) for the access of complexation. Molar ratio plots showed the formation of only one complex with stoichiometry aluminum (III):cyanidin of 1∶1 in both investigated media. Semiempirical calculations, performed in the Austin Model 1 parameterization, enabled the determination of the structural features of free compounds as well as complex structural modifications caused by chelation of Al(III). 相似文献
79.
Polyelectrolyte complex (PEC) dispersions were prepared by controlled mixing of three random copolymers of sodium 2-acrylamido-2-methylpropanesulfonate (AMPS) with either t-butyl acrylamide (TBA) [P(AMPS54-co-TBA46) and P(AMPS37-co-TBA63)] or methyl methacrylate (MM) [P(AMPS52-co-MM48)] with an ionene-type polycation, containing 95 mol % N,N-dimethyl-2-hydroxypropyleneammonium chloride repeat units (PCA5), with their structural characteristics being deeply investigated by dynamic light scattering (DLS) and atomic force microscopy (AFM). Shape, size, and polydispersity of the PEC dispersions were directly observed by AFM as a function of polyanion structure, the ratio between charges, n-/n+, and the titrant addition rate (TAR). The particle sizes increased and the colloidal stability decreased with the increase of the nonionic comonomer content and with the decrease of TAR. It was demonstrated that the medium particle sizes of the complex nanoparticles adsorbed on silicon wafers measured by AFM, in the dry state, were close but always lower than those measured by DLS, both before and after the complex stoichiometry. 相似文献
80.
This paper presents the formulation of the stress integration procedure for the Hoek-Brown (HB) material model with non-associative yielding condition by using the incremental plasticity method. Main idea of this method is to reach the solution by calculating the plastic matrix according to the method of incremental plasticity (used for elastic constitutive matrix corrections), and with the use of the total strain increment. Computational procedure is implemented within the PAK program package. Results of this procedure were compared with the solutions obtained by other program that contains this material model. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献