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61.
We demonstrate a dynamical origin for the dimension-five seesaw operator in dimensional deconstruction models. Light neutrino masses arise from the seesaw scale which corresponds to the inverse lattice spacing. It is shown that the deconstructing limit naturally prefers maximal leptonic mixing. Higher-order corrections which are allowed by gauge invariance can transform the bimaximal into a bilarge mixing. These terms may appear to be nonrenormalizable at scales smaller than the deconstruction scale. 相似文献
62.
Venkata Bharat Ram Boppana 《Journal of solid state chemistry》2011,184(5):1054-1062
We report the first instance of a hydrothermal synthesis of zinc germanate (Zn2GeO4) nano-materials having a variety of morphologies and photochemical properties in surfactant, template and catalyst-free conditions. A systematic variation of synthesis conditions and detailed characterization using X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, Raman spectroscopy, electron microscopy, X-ray photoelectron spectroscopy and small angle X-ray scattering led to a better understanding of the growth of these particles from solution. At 140 °C, the zinc germanate particle morphology changes with pH from flower-shaped at pH 6.0, to poly-disperse nano-rods at pH 10 when the Zn to Ge ratio in the synthesis solution is 2. When the Zn to Ge ratio is reduced to 1.25, mono-disperse nano-rods could be prepared at pH 7.5. Nanorod formation is also independent of the addition of cetyltrimethylammonium bromide (CTAB), in contrast to previous reports. Photocatalytic tests show that Zn2GeO4 nano-rods (by weight) and flower shaped (by surface area) are the most active for methylene blue dye degradation among the synthesized zinc germanate materials. 相似文献
63.
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65.
N.S. Venkata Narayanan B.V. Ashok Raj S. Sampath 《Electrochemistry communications》2009,11(10):2027-2031
Room temperature, magnesium ion conducting binary molten electrolyte consisting of acetamide and magnesium perchlorate has been prepared and characterized. The molten liquid is very stable and shows high ionic conductivity, of the order of several mS cm−1 at 25 °C with other favourable physicochemical properties. Vibrational spectroscopic studies reveal that the free ion concentration is higher than that of ion pairs and aggregates in the melt. The electrochemical reversibility of magnesium deposition and dissolution is demonstrated using voltammetry and impedance studies. Preliminary studies on rechargeable batteries assembled using γ-MnO2 and Mg metal as the electrodes together with the molten electrolyte show high discharge capacity. 相似文献
66.
A genetic algorithm for the two-stage supply chain distribution problem associated with a fixed charge 总被引:1,自引:0,他引:1
This paper considers a two-stage distribution problem of a supply chain that is associated with a fixed charge. Two kinds of cost are involved in this problem: a continuous cost that linearly increases with the amount transported between a source and a destination, and secondly, a fixed charge, that incurs whenever there exists a transportation of a non-zero quantity between a source and a destination. The objective criterion is the minimisation of the total cost of distribution. A genetic algorithm (GA) that belongs to evolutionary search heuristics is proposed and illustrated. The proposed methodology is evaluated for its solution quality by comparing it with the approximate and lower bound solutions. Thus, the comparison reveals that the GA generates better solution than the approximation method and is capable of providing solution either equal or closer to the lower bound solution of the problem. 相似文献
67.
D. Mohan Ganga Radhakrishnan S. Rajadurai K. Venkata Rao Gordon G. Cameron 《Journal of polymer science. Part A, Polymer chemistry》1989,27(6):2123-2133
Polyacrylamide has been grafted onto casein in phosphate buffer medium using potassium peroxodisulfate as initiator. The influence of synthetic variables on percent grafting, grafting efficiency, rates of conversion of monomer, and the rates of graft copolymerization have been discussed. A possible kinetic scheme based on experimental results has been derived. 相似文献
68.
Biswanath Das Kongara Ravinder Reddy Bommena Ravikanth Akella Venkata Subrahmanya Sarma Balasubramanian Sridhar 《Helvetica chimica acta》2008,91(6):1137-1143
Chemical investigation on two samples of the flowers of Parthenium hysterophorus afforded two new pseudoguaianolides (one from each sample) together with several known constituents. The structures of the new compounds were established by extensive spectroscopic (1D‐ and 2D‐NMR) studies. The X‐ray crystallographic analysis of one of these compounds was also accomplished. 相似文献
69.
This paper presents an optical approach to measure the oxygen gradients in biofilms grown on stainless-steel 316L. The sensor is constructed by immobilizing an oxygen-quenchable fluorophore at the tip of an optical fiber. The response time and reversibility of fiber-optic sensor have been analyzed. By mounting the optical fiber using a computerized micromanipulator, the vertical profiles of oxygen are measured with 10 μm depth resolution across biofilms on metal coupons. Steep concentration gradients of oxygen have been observed within the biofilm, both perpendicular and parallel to the metal surface. Optical response of the biofilm grown metal surface is found to be a consistent measure of the oxygen profiles within biofilms. 相似文献