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LaurenceJ. Lutsen AlbertJ. vanBreemen Willi Kreuder DirkJ.M. Vanderzande JanM.J.V. Gelan 《Helvetica chimica acta》2000,83(12):3113-3121
A new and convenient route to an unsymmetrically substituted sulfinyl monomer of precursor polymer toward poly[2‐methyl‐5‐(3,7‐dimethyloctyloxy)‐p‐phenylenevinylene] (OC1C10) is described. OC1C10 is a commercial polymer used as the active layer in LEDs. Therefore, the optimization of the reaction conditions of the monomer synthesis was of some importance for a possible commercialization of this new process. It was possible to increase the overall yield by a factor of 1.5, as compared to the route previously used to obtain these compounds. 相似文献
363.
Wavelets on closed surfaces in Euclidean space ℝ3 are introduced starting from a scale discrete wavelet transform for potentials harmonic down to a spherical boundary. Essential tools for approximation are integration formulas relating an integral over the sphere to suitable linear combinations of function values (resp. normal derivatives) on the closed surface under consideration. A scale discrete version of multiresolution is described for potential functions harmonic outside the closed surface and regular at infinity. Furthermore, an exact fully discrete wavelet approximation is developed in case of band-limited wavelets. Finally, the role of wavelets is discussed in three problems, namely (i) the representation of a function on a closed surface from discretely given data, (ii) the (discrete) solution of the exterior Dirichlet problem, and (iii) the (discrete) solution of the exterior Neumann problem. © 1998 by B. G. Teubner Stuttgart–John Wiley & Sons Ltd. 相似文献
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Karl-Heinz Pfoertner Walter Meister Willi E. Oberhnsli Peter Schnholzer Walter Vetter 《Helvetica chimica acta》1975,58(3):846-860
The base catalyzed rearrangement of 9,10,10-tricyano-5,9-methano-2,3,5,9-tetrahydro-cyclohepta[b]pyridines depends on the nature of the substituent at C(14). Seven products were isolated and identified. One structure resulting from a further ring closure was determined by x-ray analysis. 相似文献
369.
Helmut Bnnemann Werner Brijoux Rainer Brinkmann Willi Meurers 《Helvetica chimica acta》1984,67(6):1616-1624
Control of the Catalytic Synthesis of Pyridine from Alkynes and Nitriles by the (η6-Borinato)-Nigands at Cobalt η6-Borinato groups as ligands at cobalt have unique effects on the chemo- and negioselectivity of the catalytic co-cyclization of alkynes and nitriles. The turnover number of the conversion of acrylonitrile and acetylene to give 2-vinylpyridine is considerably enhanced. Cyano compounds wih polar substitutents such as amino or thio groups can also be reacted. The homogeneous reaction of HCN with acetylene giving pyridine has been achieved for the first time. 相似文献
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