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991.
Effects of electron-core relaxation in the excitation of atomic systems are considered. A new approach to the consideration of relaxation is proposed, and the corresponding equations are obtained. In the -electron approximation, the first excited states of some organic molecules are calculated by the V(N–1)-potential method, the Morokuma-Iwata method, and a method proposed in the present work.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 55–59, October, 1985. 相似文献
992.
993.
Conclusions The Wittig reaction was carried out between 2,3:4,5-diisopropylidene-al-L-arabinose and tolyloxy-methylenetriphenylphosphorane, and 2-deoxy-L-glucose was synthesized in a high yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 892–895, April, 1970. 相似文献
994.
995.
996.
997.
S. Garrigues F. J. Rambla M. de la Guardia 《Analytical and bioanalytical chemistry》1998,362(1):137-140
A comparative study has been carried out between a horizontal Attenuated Total Reflectance (h-ATR) cell and a Cylindrical Internal Reflection (CIR) cell (CIRCLE cell). Both cells were employed for the determination of glucose, fructose, sucrose and total sugar in soft drinks and fruit juices using absorbance measurements at two resolution values (4 and 8 cm–1). Data were processed by Partial Least Squares regression (PLS). Using a resolution of 4 cm–1, mean relative errors of prediction from 0.6% to 1.3% were obtained using the horizontal-ATR and from 0.6% to 2.8% using the CIRCLE cell resulting in a limit of detection from 0.03% in the case of sucrose to 0.21% for total sugar for the h-ATR and from 0.06% for sucrose to 0.13% for glucose using the CIRCLE cell. Both cells provided appropriate figures of merit, but the analytical sensitivity obtained using the h-ATR cell was three times higher than that obtained using the CIRCLE cell. 相似文献
998.
The triplet-triplet absorption spectra of a number of aromatic molecules were shown to be broadened in low temperature matrices formed by aromatic solvents (toluene, 4-isopropylbiphenyl) as compared with those in aliphatic solvents (ethanol, methylcyclohexane, triethylamine). The effect is exponentially dependent on the energy of the upper triplet state of the solute molecule. The phenomenon is discussed in terms of a strong exchange-resonance interaction between the triplet states of solute and solvent. 相似文献
999.
Yu. S. Andreichikov R. F. Saraeva S. G. Pitirimova 《Chemistry of Heterocyclic Compounds》1976,12(2):237-238
The reaction of 3-phenylethynyl-2-quinoxalones with aliphatic and aromatic amines gives alkyl(aryl)imines of 3-phenacylidene-2-quinoxalone, the structures of which were proved by alternative synthesis from 3-phenacylidene-2-quinoxalone and the appropriate amines.See [1] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 276–277, February, 1976. 相似文献
1000.