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Several models have been developed in order to categorize the numerous expressions that people use in order to describe their emotional experiences. The focus of the present study is on one of these theoretical classifications proposed by Pekrun (1992) specifically concerning emotions which are directly related to learning and achievement in mathematics. In his model, emotions are classified according to their valence (positive vs. negative) and their level of activation. In testing the assumptions of this model, we investigated students' enjoyment, anxiety, anger and boredom experienced before, during, and after the completion of a math test. Correspondence analyses which were used to generate a graphical illustration of structural interrelationships between these emotions provide empirical support for the theoretical classification. 相似文献
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Willi Jager Peter Lax Cathleen Synge Morawetz 《Journal of Mathematical Sciences》2004,120(3):1242-1246
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A. V. Willi 《Helvetica chimica acta》1966,49(5):1725-1728
Second order rate constants are determined for the E2 reactions of 2,2-diphenyl-ethyl benzenesulfonates Ph2CxHCH2O · O2S–C6H4–X with CH3ONa in methyl cellosolve solution (xH = H or D, X = p-CH3O, p-CH3, H or p-NO2). The HAMMETT ? values are of the same order of magnitude as those found in the first order solvolyses of methyl, ethyl or isopropyl benzenesulfonates. The primary deuterium isotope effects kH/kD are 5.27, 5.42 and 6.70 for X = p-CH3O, H and p-NO2. The ? values as well as the increase of kH/kD with introduction of p-NO2 supply evidence for simultaneous CαO and CβH bond cleavages also in the E2 reactions of these compounds. 相似文献
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Alfred V. Willi 《Helvetica chimica acta》1973,56(6):2094-2098
It is suggested that the acid catalyzed hydrolyses of isobutene oxide and propene oxide proceed via rate-determining bimolecular reaction between a carbonium ion and solvent water (A2+ mechanism). The carbonium ion is formed by ring opening of the protonated epoxide, in a relatively fast preceding step. This mechanism is in agreement with all experimental facts known today. There is evidence for a similar mechanism in the acid catalyzed hydrolyses of cyclic acetals. 相似文献