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61.
Oxidation of the title compound with m-chloroperbenzoic acid affords a keto-lactone, two bis-lactones and a bis-spirolactone, in varying amounts depending upon the reaction conditions. The structures were established by means of X-ray diffraction, 1H- and 13C-NMR spectroscopy.  相似文献   
62.
Experiments on solidification of aqueous solutions are sometimes carried out in tanks with transparent sidewalls to allow visualization of the flow and crystal structure. The tank sidewalls must be thermally insulated and condensation of water vapor on the outer sidewalls must be prevented for clear visualization. In this note a system is presented which is capable of eliminating the water vapor condensation, providing thermal insulation and thus facilitating continuous flow visualization of the solidification process. Some visualization photographs are presented. Received: 19 April 1999 / Accepted: 30 July 1999  相似文献   
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Equations of the strength surface are proposed. The equations contain second- and fourth-power terms with respect to stresses acting over the areas of structural symmetry in the orthropic material.Mekhanika Polimerov, Vol. 3, No. 4, pp. 703–707, 1967  相似文献   
67.
Reaction of 1,2-dihydrophthalic anhydride and several of its imide derivatives, 1,2-dihydrophthalide and 1,2-dihydrophthalan with N-methyl- and N-phenyl-1,2,4-triazoline-3,5-dione affords two configurational families of adducts through attack from both possible directions. Major attack in the first three cases occurs mainly syn- to the hetero-ring but in the two latter cases anti- to it. These results may be explained by invoking stabilization of the transition state in the former cases through secondary orbital overlap and by simple steric effects in the latter.  相似文献   
68.
It is shown that the Fröhlich approach for calculating electron-phonon coupling constants based on wave functions moving with the vibrating atoms can be set on a rigorous basis. This approach and the Bloch approach are shown to lead to the same physical results provided that one stays within the adiabatic approximation and considers both first and second order vertices (in the harmonic approximation). Advantages of the Fröhlich approach in past and in possible future calculations are discussed.  相似文献   
69.
Electromotive force measurements have been made using the cell $$\mbox{In(s)}|\mbox{HCl }(m_{\mathrm{A}}),\mbox{InCl}_{3}(m_{\mathrm{B}}),\mbox{H}_{2}\mbox{O}|\mbox{AgCl, Ag}$$ in the ionic strength range of I=0.05, 0.1, 0.25, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mol?kg?1 at 25?°C. The value of E o, the standard potential of the In/In3+ electrode, has been determined at 25?°C. Our value of E o (?0.3371 V) at 25?°C obtained from our measurements is in good agreement with ?0.336 (Hakomori, J. Am. Chem. Soc. 52: 2372–2376, 1930) and ?0.3382 V (Covington et al., J. Chem. Soc. 4394–4401, 1963). The activity coefficients of InCl3 as well as Harned interaction coefficients have been determined at 25?°C for each of the experimental ionic strengths at ionic strength fractions of 0.1, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9 of HCl. Harned’s rule for the salt is obeyed at I=0.05,0.1 and 0.25 mol?kg?1 but the quadratic terms are needed for higher ionic strengths. These data, together with others for the activity coefficient of HCl in the same solutions, have been treated by the ion-interaction (Pitzer, Activity Coefficients in Electrolyte Solutions, CRC Press, 1991) equations in a previous publication.  相似文献   
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