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31.
Summary Gradient elution RP-HPLC has been applied to the separation of the constituents of synthetic tanning agents. Information obtained from the chromatographic results was used to assess the possibility of optimizing the conditions of synthesis, to find out the number of species formed and to make a start at correlating the composition of the tanning agents and their properties. 相似文献
32.
Summary Gas chromatographic unified retention indices for 43 hydrocarbons (alkanes and cycloalkanes) are given for squalane and OV-101. Comparison of these values and unified retention index increments are presented as linear regression equations with high correlation coefficients and acceptable standard deviations. 相似文献
33.
Jayshree Ramkumar 《Talanta》2007,71(3):1054-1060
The single ion transport of transition metal ions like Cu2+, Co2+, Ni2+ and Zn2+ were carried out through the H+ and alkali metal ion forms of Nafion membrane. These studies showed that the ion exchange selectivity coefficient of the permeating ion had an effect on its transport process. It was found that the diffusion coefficient values (D) were directly proportional to the selectivity coefficient (K). This shows that the initial stage of permeation is governed by ion exchange process (effect of K on D). 相似文献
34.
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36.
Dr. E. L. Mehler 《Theoretical chemistry accounts》1974,35(1):17-32
A new method is proposed for calculating correlation effects in atomic and molecular systems. The basis of the method is the
formulation of a set of partial configuration expansions which yield directly variational orbital correlation corrections
which are appropriately summed in order to obtain an estimate of the total correlation energy. This method is applied to the
ground state of boron hydride and its cation at the equilibrium distance of BH. The results of the method are compared in
detail with independent electron pair results and second order CI results. It is further shown that multiple substitutions
are approximately accounted for in this method and the extent to which they are included is compared with other approximations.
Finally, three methods of increasing accuracy, aimed at reducing the necessary computational effort, are given for determining
the vertical ionization potential. The most economical method yields an IP of 9.70 eV or 0.03 eV less than the experimental
IP. Completion of the basis is estimated to improve this value to 9.77 eV. 相似文献
37.
This paper concerns the application of excess adsorption isotherms, measured for solvent mixture/adsorbent systems, to the characterization of TLC data. For this purpose the excess adsorption isotherms for three liquid mixtures: cyclohexane/ benzene, benzene/acetone, and carbon tetrachloride/ethyl acetate on silica gel at 20°C have been measured. These mixtures have been used as binary mobile phases in TLC measurements. It has been shown for a given solute in binary mobile phase that the quantity RM is a simple function of the excess adsorption. Parameters of this function have been used to characterize chromatographic systems with binary mobile phases. 相似文献
38.
With measurement uncertainty estimation accounting for all relevant uncertainty contributions, the results of measurements using the same procedure on different objects or samples may no longer be considered as being independent, and correlations have to be taken into account. For this purpose, a simple approximation for the estimation of covariances is derived and applied to the estimation of uncertainty for some basic combinations of two measurement results. This covariance estimate is also applied to the estimation of uncertainty for the mean value of the results of replicate measurements on the same object or sample.
相似文献
W. HaesselbarthEmail: Phone: +49-30-81041101Fax: +49-30-81045577 |
39.
Mariana Ramos-Estrada Gustavo A. Iglesias-Silva Kenneth R. Hall F. Kohler 《Fluid Phase Equilibria》2006,240(2):179-185
We use the Clausius–Clapeyron equation to calculate third virial coefficients at low reduced temperatures. This procedure gives an alternative to predict third virial coefficients in a region where the third virial coefficient is difficult to measure. We compare the results of this method with published third virial coefficient data. Calculated third virial coefficients have average percentage deviations within 5% of the experimental values at reduced temperatures between 0.8 and 1.0. 相似文献
40.