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991.
Gholamhosein H. Hakimelahi Charles B. Boyce Hamid S. Kasmai 《Helvetica chimica acta》1977,60(2):342-347
The synthesis of phenathrenes substituted by nitrogen and oxygen atoms in position 9 and 10 by photolysis of 4,5-diphenyl-oxazol-2-ones (cf. Scheme 4) is described. Moreover an improved general procedure for the synthesis of benzoins in aprotic solvent (tetra-t-butylammonium cyanide in DMF/DMSO) is developed. 相似文献
992.
993.
Charles E. Blair 《Mathematical Programming》1978,15(1):87-91
The duality theorem of linear programming is used to prove several results on convex optimization. This is done without using separating hyerplane theorems.This work was supported in part by a grant from Investors in Business Education. 相似文献
994.
995.
Charles C. Price Anthony L. Tumolo 《Journal of polymer science. Part A, Polymer chemistry》1967,5(1):175-181
Ozonation followed by lithium aluminum hydride reduction cleaved high molecular weight isotactic poly(propylene oxide) to crystalline polyglycols. From the melting point and molecular weight of the latter, the molar freezing point depression produced by end groups is found to be ca. 18°C./mole, as compared to that estimated for poly(ethylene glycols), Kf = 12°C./mole, from earlier data. By assuming syndiotactic placements (or other irregularities) would produce the same molar depression, the melting point of isotactic poly(propylene oxides) produced by various catalysts has been used to estimate the isotactic sequence lengths. 相似文献
996.
Charles W. Koch Dolan H. Eargle George L. Kenyon 《Journal of mass spectrometry : JMS》1977,12(10):624-627
Electron impact induced fragmentations and rearrangements of 1-phenyl-2,2,3-trimethylphosphetane 1-oxide, 1-phenylphospholane 1-oxide and 1-phenylphosphorinane 1-oxide were investigated. A process common to all of these phosphine oxides was electron impact induced formation of new carbon-carbon bonds involving the phenyl rings. Evidence for such rearrangements included observation of hydrocarbon fragment ions containing seven or more carbons. 相似文献
997.
Using the concepts of conditional expectation and independence of subalgebras, we characterize those contractive projections, P, on Lp, over a probability measure space, having the property that I − P is contractive. By contractive projection we mean a linear operator, P, on the Lebesgue space, Lp, 1 < p < ∞, ≠2, with P2 = P, ∥ = 1. 相似文献
998.
Charles L. Gruner Bernhard Wunderlich Richard C. Bopp 《Journal of Polymer Science.Polymer Physics》1969,7(12):2099-2113
Polyethylene crystals of different degrees of perfection were annealed at 5.1 kb pressure for 20 hr at various temperatures and analyzed by electron microscopy, thermal analysis, and density determination. No annealing took place until the temperature was close to the melting point of the starting material. Up to 235°C increasing solidstate annealing was observed. Mixed crystals of up to 0.989 g/cm3 density and 1500 Å thickness in the chain direction could be produced. At slightly higher temperature recrystallization to extended-chain crystals rather than annealing occurred. The annealing process at atmospheric pressure seems to be similar in nature, but takes much longer for comparable perfection. From a comparison of annealing and crystallization it is concluded that polymer crystallization goes through a stage of internally imperfect order during which most of the observed chain extension occurs. Estimates of this outer imperfect layer of a growing crystal place its depth at 30,000 Å. 相似文献
999.
Charles N Friedman 《Annals of Physics》1976,98(1):87-97
We study the nature and effects of some continual measurements in nonrelativistic quantum mechanics, a concept introduced by R. P. Feynman in his path integral formulation of quantum mechanics. We prove the existence in various senses of mathematically rigorous objects formally equivalent to the path integrals associated with such measurements, by means of both a limiting definition and more general techniques; and we derive some quantitative results concerning the effects on the wave-function and the numerical value of certain associated probabilities. 相似文献
1000.
The question of which C1-algebras have only inner derivations has been considered by a number of authors for 25 years. The separable case is completely solved, so this paper deals only with the non-separable case. In particular, we show that the C1-tensor product of a von Neumann algebra and an abelian C1-algebra has only inner derivations. Other special types of C1-algebras are shown to have only inner derivations as well such as the C1-tensor product of L(H) (all bounded operators on separable Hilbert space) and any separable C1-algebra having only inner derivations. Derivations from a smaller C1-algebra into a larger one are also considered, and this concept is generalized to include derivations between C1-algebras connected by a 1-homomorphism. Finally, we consider the general problem of a sequence of linear functionals on a C1-algebra which converges to zero (in norm) when restricted to any abelian C1-subalgebra. Does such a sequence converge to zero in norm? The answer is “yes” for normal functionals on L(H), but unknown in general. 相似文献