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221.
The first comprehensive study of shallow shell vibrations subjected to as many as 21 possible boundary conditions is presented. Thin shallow shell theory is used. Relatively accurate results for natural frequencies of doubly-curved shallow shells have been obtained. These can be used for benchmarking by researchers as well as reference data for practicing engineers. The Ritz method is used to solve for natural vibrations of these shells with arbitrary boundary conditions. Natural frequencies are presented for various shell curvatures including spherical, cylindrical and hyperbolic paraboloidal shells. 相似文献
222.
Ladder operators for the radial index of the paraxial optical modes in the cylindrical coordinates are calculated. The operators obey the su(1,1) algebra commutation relations. Based on this Lie algebra, we found that coherent modes constructed as eigenstates of the destruction operator or resulting from the action of the displacement operator on the fundamental mode are different. Some properties of these two kinds of radial coherent modes are studied in detail. 相似文献
223.
A straightforward and efficient method for the synthesis of 1,2-dihydroisoquinolines via the one-pot, three-component reaction of an isocyanide, isoquinoline and a strong CH-acid in water without using any catalyst at 70 °C is reported. The method offers several advantages including high yields of products and an easy work-up procedure. 相似文献
224.
Darush Afzali Ali Mostafavi Mohammad Ali Taher Ebrahim Rezaeipour Mohammad Khayatzadeh Mahani 《Analytical sciences》2005,21(4):383-386
A procedure for separation and preconcentration of trace amounts of cadmium has been proposed. A column of analcime zeolite modified with benzyldimethyltetradecylammonium chloride and loaded with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) was used for retention of cadmium. The cadmium was quantitatively retained on the column at pH approximately 9 and was recovered from column with 5 ml of 2 M nitric acid with a preconcentration factor of 140. Anodic stripping differential pulse voltammetry was used for determination of cadmium. A 0.05 ng/ml detection limit for the preconcentration of aqueous solution of cadmium was obtained. The relative standard deviation (RSD) for eight replicate determinations at the 1 microg/ml cadmium levels was 0.31% (calculated with the peak height obtained). The calibration graph using the preconcentration system was linear from 0.01 to 150 microg/ml in final solution with a correlation coefficient of 0.9997. For optimization of conditions, various parameters such as the effect of pH, flow rate, instrumental conditions and interference of number of ions, were studied in detail. This method was successfully applied for determination of cadmium in various complex samples. 相似文献
225.
Linh B. Truong David Medina-Cruz Ebrahim Mostafavi Navid Rabiee 《Molecules (Basel, Switzerland)》2021,26(12)
The rise of antimicrobial resistance to antibiotics (AMR) as a healthcare crisis has led to a tremendous social and economic impact, whose damage poses a significant threat to future generations. Current treatments either are less effective or result in further acquired resistance. At the same time, several new antimicrobial discovery approaches are expensive, slow, and relatively poorly equipped for translation into the clinical world. Therefore, the use of nanomaterials is presented as a suitable solution. In particular, this review discusses selenium nanoparticles (SeNPs) as one of the most promising therapeutic agents based in the nanoscale to treat infections effectively. This work summarizes the latest advances in the synthesis of SeNPs and their progress as antimicrobial agents using traditional and biogenic approaches. While physiochemical methods produce consistent nanostructures, along with shortened processing procedures and potential for functionalization of designs, green or biogenic synthesis represents a quick, inexpensive, efficient, and eco-friendly approach with more promise for tunability and versatility. In the end, the clinical translation of SeNPs faces various obstacles, including uncertain in vivo safety profiles and mechanisms of action and unclear regulatory frameworks. Nonetheless, the promise possessed by these metalloid nanostructures, along with other nanoparticles in treating bacterial infections and slowing down the AMR crisis, are worth exploring. 相似文献
226.
227.
Ebrahim Samei 《Journal of Functional Analysis》2006,231(1):195-220
We study certain commutative regular semisimple Banach algebras which we call hyper-Tauberian algebras. We first show that they form a subclass of weakly amenable Tauberian algebras. Then we investigate the basic and hereditary properties of them. Moreover, we show that if A is a hyper-Tauberian algebra, then the linear space of bounded derivations from A into any Banach A-bimodule is reflexive. We apply these results to the Figà-Talamanca-Herz algebra Ap(G) of a locally compact group G for p∈(1,∞). We show that Ap(G) is hyper-Tauberian if the principal component of G is abelian. Finally, by considering the quantization of these results, we show that for any locally compact group G, Ap(G), equipped with an appropriate operator space structure, is a quantized hyper-Tauberian algebra. This, in particular, implies that Ap(G) is operator weakly amenable. 相似文献
228.
229.
Rana Khalilnezhad Mohammad Ebrahim Olya Morteza Khosravi Reza Marandi 《Applied biochemistry and biotechnology》2014,174(5):1919-1934
Biosorption of manganese(II) using suspended and immobilized cells of fungal Penicillium camemberti (biomass) and nano-P. camemberti (nano-biomass) was studied by evaluating the physicochemical parameters of the solution such as initial manganese ion concentration, pH, temperature, dosage, and contact time in both batch system and fixed bed column. The maximum biosorption obtained from the batch process was 91.54 and 71.08 % for nano-biomass and biomass in initial concentration of 5 ppm, respectively. The Langmuir, Freundlich, Temkin, and BET isotherms isotherm models were used in the equilibrium modeling. The correlation coefficient of more than 0.90 turned out that the adsorption process of Mn(II) on biomass and nano-biomass were in accordance with both Langmuir and Freundlich isotherms. The sorption process followed a second-order rate kinetics indicating the process to be diffusion controlled. The results also demonstrate that an intra-particle diffusion mechanism plays a significant role in the sorption process. The structure of P. camemberti was characterized by FT-IR spectrums. 相似文献
230.
Hamid Reza Shaterian Marziyeh Sedghipour Ebrahim Mollashahi 《Research on Chemical Intermediates》2014,40(4):1345-1355
An environmentally green method for the synthesis of 13-aryl-5H-dibenzo[b,i]xanthene-5,7,12,14(13H)-tetraone and 3,4-dihydro-1H-benzo[b]xanthene-1,6,11(2H,12H)-trione derivatives using Brønsted acidic ionic liquids, 3-methyl-1-sulfonic acid imidazolium chloride, 1-H-3-methyl-imidazolium hydrogensulfate, triethylamine-bonded sulfonic acid, and triethylammonium hydrogensulfate as reusable catalysts under thermal solvent-free conditions is described. 相似文献