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301.
Ugur Cem Hasar Joaquim José Barroso Yunus Kaya Mehmet Ertugrul Musa Bute José M. Catalá-Civera 《Applied Physics A: Materials Science & Processing》2014,116(4):1701-1710
A two-step measurement procedure has been proposed for measurement of complex permittivity of dielectric materials using one-port reflection measurements. In the procedure, as a first step, a graphical method is applied to analyze on the complex reflection-coefficient plane the general pattern of dielectric behavior of the sample. Then, as a second step, optimization algorithms are utilized for retrieving electrical properties of samples. The procedure requires measurement of complex reflection scattering parameters of at least two samples with different lengths. It has been validated by X-band measurements of three polyvinyl chloride samples with lengths 5, 10, and 20 mm. 相似文献
302.
Using series iteration techniques identities and apply each of these identities in we derive a number of general double series order to deduce several hypergeometric reduction formulas involving the Srivastava-Daoust double hypergeometric function. The results presented in this article are based essentially upon the hypergeometric summation theorems of Kummer and Dixon. 相似文献
303.
Musa S Romm R Azerraf C Kozuch S Gelman D 《Dalton transactions (Cambridge, England : 2003)》2011,40(35):8760-8763
Ligand-metal cooperation in iridium and platinum complexes bearing tricyclic dibenzobarrelene-based PC(sp(3))P pincer ligands is discussed. We demonstrated that the carbon-metal bond in these complexes may be efficiently cleaved and regenerated via 1,2-addition/elimination reactions. 相似文献
304.
305.
Twenty acid chlorides, 4-(mono/di-benzyloxy)-4-ketobutanoyl chlorides (Ia–XXa) were synthesised by the reaction of monoesters of succinic acid with thionyl chloride. The product thus obtained (4-benzyloxy-4-ketobutanoyl chlorides) was treated with diethylcadmium to convert it into the corresponding keto-esters (Ib–XXb), the mono/di-benzyl-γ-ketohexanoates, with a good yield. All the compounds thus prepared were characterised by physical, spectroscopic (UV-VIS, IR, 1H NMR, 13C NMR), and mass measurements techniques. 相似文献
306.
Cihangir Boztepe Musa Solener Asim Kunkul Osman S. Kabasakal 《Journal of Dispersion Science and Technology》2013,34(11):1647-1656
Hydrogels based on acrylamide (AAm) were synthesized by free radical polymerization in an aqueous solution using N,N’-methylenebisacrylamide (MBAAm) as crosslinker. To obtain anionic hydrogels, 2-acrylamido-2-methylpropanesulfonic acid sodium salt (AMPS) and acrylic acid (AAc) were used as comonomers. The swelling behaviors of all hydrogel systems were modeled using an artificial neural network (ANN) and compared with a multivariable least squares regression (MLSR) model and phenomenal model. The predictions from the ANN model, which associated input parameters, including the amounts of crosslinker (MBA) and comonomer, and swelling values with time, produce results that show excellent correlation with experimental data. The parameters of swelling kinetics and water diffusion mechanisms of the hydrogels were calculated using the obtained experimental data. Model analysis indicated that the ANN models could accurately describe complex swelling behaviors of highly swellable hydrogels. 相似文献
307.
Musa Kaleem Baloch 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):363-372
Viscosity measurements of cellulose acetate and polyisobutylene over a wide range of concentrations and molecular weights have been made. The data so obtained and the data taken from the literature for schizophyllan show that the viscosity varies smoothly with concentration of the polymer for the whole range of concentrations and molecular weights investigated. The characteristic concentrations, Cch , of the polymers are calculated by the following equations: Cch = 0.77/[η] or Cch = 1.08/[η]. The relationship between molecular weight and intrinsic viscosity is obtained by fitting the data by the method of least squares. By plotting the reduced viscosity versus the reduced concentration, superposition curves are obtained for both cellulose acetate and polyisobutylene. It is not possible to obtain superposition curves for schizophyllan, which is a more rigid polymer. 相似文献
308.
Irfan Ullah Musa Kaleem Baloch Gulrez Fatima Durrani 《Journal of solution chemistry》2011,40(7):1341-1348
The solubilities of two nonsteroidal anti-inflammatory (MELOXICAM and CELECOXIB) drugs, were determined in aqueous solutions
of nonionic (Tween 20, Tween 80, Brij 30, Brij 35, Triton X 100, Triton X 114) surfactants. These surfactants have different
numbers of oxyethylene units and their micelles showed different aggregation numbers. It is shown that these surfactants have
different abilities to solubilize NSAIDs drugs. The solubilities of the drugs increased linearly with the increase in concentration
of surfactants. The sizes of micelles remained constant with the addition of the drugs, except for Triton type surfactants
in which case the size of the micelles decreased. It was observed that the number of oxyethylene units in the surfactants,
aggregation number of the micelles and HLB play key roles in solubilizing the drugs. 相似文献
309.
Magnetic properties, arising from surface exchange and interparticle interactions of the Fe3O4 (magnetite) nanoparticles, were investigated in the temperature range of 5–300 and 120–300 K using vibrating sample magnetometer
technique and electron spin resonance spectroscopy, respectively. The research was based on to figure out the origin of intraparticle
interactions and the change of interparticle interactions in wide size range Fe3O4 nanoparticles. The analyses were done for samples having almost same particle size distributions. The average particle sizes
were changed in between 30 ± 2 and 34 ± 2 nm. The observed magnetization values were demonstrated the mixture of single-domain
size particles, exhibiting both single-domain (SD) and superparamagnetic (SPM) states. The symmetry of resonance curves changed
according to the ratio of SD and SPM-stated particles in mixture under located temperature. The changes of anisotropy up to
domain state were understood by freezing magnetic moment in glycerol matrix from room temperature to 120 K under 5-kG field.
The shift of H
R values to higher magnetic fields and the more symmetric resonance spectrum proved the effect of anisotropy and interparticle
interactions fields on magnetic behave. In addition, the origin of intra-interaction was exposed from Fe3+ centers and exchange coupling in between Fe2+, Fe3+, and O−, and Fe3+ centers found from g factor (g). 相似文献
310.