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排序方式: 共有740条查询结果,搜索用时 46 毫秒
41.
The paper reports a structural study of some memory and threshold chalcogenides in terms of coordination numberC, defined byC=8−N, and is the average coordination number for covalently bonded materials. The average number of nearest neighbours surrounding
a central atom, obtained for As-Ge-Te (memory) and Se-Ge-Te (threshold) systems have been used to estimate the cohesive energies,
assuming simple additivity of bond energies. The bonding pattern so obtained, explains certain properties of these glasses. 相似文献
42.
Electrochemical oxidation of uric acid in phosphate-containing supporting electrolytes between pH 3–9 at a reticulated vitreous carbon electrode in a thin-layer spectroelectrochemical cell leads to formation of U.V.-absorbing intermediate species. Electrochemical reduction of the intermediate-containing solution leads to the partial regeneration of uric acid. This behavior provides compelling evidence that an imine-alcohol is one of the U.V.-absorbing intermediate species since only this compound may be expected to be reduced to a species which can regenerate uric acid. 相似文献
43.
Polarographic reduction of 2-amino-4-aryl-5-phenylazothiazoles takes place in a single 2-electron transfer, giving a diffusion-controlled irreversible wave in the pH range 2.0-10.0. Substituents in the 4-position of the thiazole moiety shift the half-wave potential through conjugation of the system. A correlation of E(sol;1 2 ) with the Brown and Hammett substituent constant has also been established. 相似文献
44.
45.
The generation of a circular fringe system of Newton rings' type with dark fringe at the centre is described. Such fringes are localized at infinity and are produced by a pair of longitudinally displaced mutually complimentary diffusers. Experimental results under various displacement configurations have been presented. 相似文献
46.
S. K. Goyal 《The Journal of the Operational Research Society》1973,24(3):391-401
A first attempt at applying OR techniques and approaches in a fine art printing firm manufacturing greeting cards is reported in this paper. The problem of economic production of cards is formulated and four related methods are presented, the fourth being a probabilistic model with possibly wider applications in the fashion industry 相似文献
47.
S.K. Goyal 《European Journal of Operational Research》1980,4(3):185-188
The search procedure developed in this paper is typically applicable in those inventory systems where a product is packaged immediately after manufacture into a number of container sizes and the packaged items of similar sizes are sold under more than one brand name. The most common example of such items can be seen in supermarkets where grocery items of identical characteristics (produced by the same manufacture) are available under the supermarket's own brand and under the manufacturer's nationally advertised brand. An example has been solved to illustrate the method. 相似文献
48.
49.
Wavelength beam combining of five ytterbium fiber lasers is demonstrated in a master-oscillator power-amplifier configuration at combined powers up to 6 W. The combined beam profile has an M2 value of 1.14, which is equal to that of an individual fiber. Beam steering in one dimension over 140 resolvable spots is also demonstrated. 相似文献
50.
We answer in negative a question of Gál and Miltersen [Proc 30th Int Coll Automata, Languages, and Programming (ICALP) 2003, pp. 332–344] about a combinatorial game arising in the study of time‐space trade‐offs for data structures. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2005 相似文献