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981.
982.
Two conjugated polymers HXS-1 and PDFCDTBT were prepared by direct C–H activation and Suzuki polycondensation and their chemical structures were characterized by 1H NMR spectroscopy.The molecular weight of conjugated polymer synthesized by direct C–H activation is lower than the corresponding polymers prepared by Suzuki polycondensation.Conjugated polymers synthesized by direct C–H activation have considerable solubility in common organic solvents and form amorphous film.The photovoltaic property of conjugated polymers synthesized by direct C–H activation is inferior to the corresponding polymers synthesized by Suzuki polycondensation. 相似文献
983.
984.
985.
986.
Achiral epoxides are isomerized to optically active allylic alcohols under the influence of catalytical amounts of cob(I) alamin in protic polar solvents. 相似文献
987.
It is argued that even for a linear system of ODEs with constant coefficients, stiffness cannot properly be characterized in terms of the eigenvalues of the Jacobian, because stiffness is a transient phenomenon whereas the significance of eigenvalues is asymptotic. Recent theory from the numerical solution of PDEs is adapted to show that a more appropriate characterization can be based upon pseudospectra instead of spectra. Numerical experiments with an adaptive ODE solver illustrate these findings.Supported by a Dundee University Research Initiatives Grant.Supported by NSF Grant DMS-9116110. 相似文献
988.
Heng Jiang Yun Xu Shijian Liao Daorong Yu 《Reaction Kinetics and Catalysis Letters》1998,63(1):179-183
In the absence of solvent, the first-row transition-metal acetylacetonate complexes and RuCl2(PPh3)3 give fairly high turnovers for the allylic oxidation of cyclohexene under atmospheric pressure of oxygen. Synergetic effect
is observed for the oxidation of cyclohexene by using M(acac)n−RuCl2(PPh3)3 bimetallic catalysts. 相似文献
989.
Hyperfine Interactions - The demand by industrial researchers to characterize commercial materials with high precision has seen the growth of many spectroscopic techniques in the broad area of... 相似文献
990.
The specific energy of several types of Australian coal was determined directly by DSC, using a standard coal as calibrant. By subdivision of the combustion profile into separate peaks representing combustion of volatile matter and residual char, the specific energies of these components were also determined. 相似文献