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91.
The dc conductivity of semiconducting cobalt-phosphate glasses has been measured at temperatures ranging from 213 to 530 K. Four bulk samples of CoO-P2O5 glasses of different compositions were produced by melting dry mixtures of analytical reagent grades of CoO and P2O5 at temperatures between 1200-1250 °C for 2 h using a press-quenching method from glass melt. Samples were annealed at 400 °C for 1 h. The dc conductivity was found to be dependent on the CoO content in the glass. At temperatures from 213 to 444 K, however, both Mott's variable-range hopping (VRH) and the Greaves' intermediate range hopping models are found to be applicable. VRH at this range of temperatures is attributed to large values of the disorder energy of these glasses. 相似文献
92.
S. Sadiq Basha 《Optimization Letters》2013,7(6):1167-1177
The purpose of this article is to resolve the non-linear programming problem of globally minimizing the real valued function ${x \longrightarrow d(x, Sx)}$ where S is a non-self-mapping in the setting of a metric space with the distance function ‘d’. An iterative algorithm is also furnished to find a solution of such global optimization problems. As a consequence, one can determine an optimal approximate solution to some equations of the form Sx = x. 相似文献
93.
Ponnapalli Mangala Gowri Sri Vedavyasa Srirangaraja Radhakrishnan Bhattar Poreddy Guruva Reddy Yerraballi Rakesh Shaik Jeelani Basha Akella Venkata Subrahmanya Sarma Janaswamy Madhusudana Rao 《Helvetica chimica acta》2009,92(7):1419-1427
An extensive study of metabolites present in Excoecaria agallocha Linn . led to the isolation of three new ent‐labdane‐type diterpenoids, named agallochaexcoerins A–C ( 1 – 3 ), besides three known compounds. The skeleton present in compound 1 is rather unusual, containing of a seven‐membered lactone. The structures were elucidated on the basis of spectroscopic studies and comparison with known related compounds. The isolated compounds 1 – 6 were not active against Raw 264.7 (macrophage‐like), K 562 (leukemia), and COLO 205 (colon) human carcinoma cell lines. 相似文献
94.
Syntheses of the acyclic chains of verrucarin A and J are described; the revised stereochemistry of verrucarin J is confirmed. 相似文献
95.
96.
97.
Venkatapuram Padmavathi Shaik Mahaboob Basha Dandu Rangayapalle Chinna Venkata Subbaiah Tippireddy Venkata Ramana Reddy Adivireddy Padmaja 《Journal of heterocyclic chemistry》2005,42(5):797-802
Novel spiro heterocycles, substituted spiro‐pyrimidine, pyrazole and isoxazole compounds are prepared by the cyclocondensation of 4‐oxocyclohexane gem‐dicarboxylates and cyano esters with nucleophiles. 相似文献
98.
Active dissolution and passivation of transition metals in alkali solutions is of technological importance in batteries. The performance of alkaline batteries is decided by the presence of halides as they influence passivation. Cyclic voltammetric studies were carried out on iron in different sodium hydroxide solutions in presence of halides. In alkali solutions iron formed hydroxo complexes and their polymers in the interfacial diffusion layer. With progress of time they formed a cation selective layer. The diffusion layer turned into bipolar ion selective layer consisted of halides, a selective inner sublayer to the metal side and cation selective outer layer to the solution side. At very high anodic potentials, dehydration and deprotonation led to the conversion of salt layer into an oxide. 相似文献
99.
Experiments have been conducted in a low speed horizontal wind tunnel to study the interaction of radiation and conduction on mixed convective heat transfer from an upward facing horizontal flat plate in air. Differential interferometer has been used to measure local convective heat fluxes. It has been observed that interaction between surface radiation and convection is significant for a low thermal conductivity plate material. On the basis of the previous and current studies, it can be stated that the multi-mode interaction problem is an outcome of the nature of convective boundary layer. The interaction between different modes of heat transfer would remain similar irrespective of the nature of convection (free/mixed or forced). 相似文献
100.
An efficient and easy procedure for the one‐pot synthesis of spirooxindoles in the presence of Na2CO3 in water : methanol (1:1) is described. The salient features of this method are simple methodology, shorter reaction time, easy product isolation, and no chromatographic purification. 相似文献