Sixteen indole derivatives have been computed at B3LYP/6-31 IG^＊＊ level using density functional theory （DFF）. Based on linear solvation energy theory, the structural parameters were employed to present correlatio...Sixteen indole derivatives have been computed at B3LYP/6-31 IG^＊＊ level using density functional theory （DFF）. Based on linear solvation energy theory, the structural parameters were employed to present correlation between the parameters of chromatograph capacity factor （CCF） and molecular structural parameters. As a result, the correlation equation of the reversed phased high performance liquid chromatograph capacity factor to the intercept lgk＇w and slope S of CCF were obtained, from which the correlation coefficients of lgk＇w to the structural parameters are r^2 = 0.9596 and q^2 = 0.9262. While the correlation coefficients of the parameter S r^2 q^2 with structures are = 0.9750 and = 0.9252. Moreover, the effect of water as solvent on the present two models was also considered using SCRF method, and the result shows that the predicting capacity of correlation equation of lgkw＇ increases, while that of the model for S decreases slightly. Both two correlation equations achieved in this work are more advantageous than those using theoretical descriptors from molecular connectivity indices.展开更多
The chroma difference(DC) and lightness difference (DL) of 288 jadeite-jades with fine texture and even green color have been analyzed based on color difference formula CIE LAB in the uniform color space CIE 1976 L^~*...The chroma difference(DC) and lightness difference (DL) of 288 jadeite-jades with fine texture and even green color have been analyzed based on color difference formula CIE LAB in the uniform color space CIE 1976 L^~*a^~*b^~* to evaluate their contribution to the color appearance and color difference(DE).The analysis of lightness(L^~*), chroma(C^~*) and hue-angle(h_o) show that the vivid yellowish green color occurs when L^~*∈5.29-59.2,展开更多
The present paper covers the actional mechanism of trifluoroacetic acid for the separation of biopolymers investigated by using the parameters of stoichiometric displacement model for retention(SDM-R) in reversed-phas...The present paper covers the actional mechanism of trifluoroacetic acid for the separation of biopolymers investigated by using the parameters of stoichiometric displacement model for retention(SDM-R) in reversed-phase liquid chromatography. It was found that the trifluoroacetic acid(TFA) may participate in, or stimulate the association among displacing agent molecules in mobile phase, and decrease the affinity of both the associate molecules of the displacing agent and the TFA-protein ion-pairing. The former dominates over the separation selectivity of biopolymers as the concentration of TFA is lower than a given value, and the two contrary functions partly offset to each other and the latter dominates as its concentration is greater than the given value.展开更多
Total phosphorus is an important index for surface water evaluation. Surface water presents certain turbidity and chromaticity due to its silt, plankton, inorganic substances and organic substances. At present, the de...Total phosphorus is an important index for surface water evaluation. Surface water presents certain turbidity and chromaticity due to its silt, plankton, inorganic substances and organic substances. At present, the determination of total phosphorus in the laboratory is mostly by spectrophotometry. Therefore, it is of great significance to explore the influence of chromaticity and turbidity on the determination of total phosphorus in the laboratory. In this paper, different concentrations of total phosphorus solution are selected to analyze the influence of chromaticity and turbidity on total phosphorus respectively. The experimental results show that when the turbidity of water sample is less than 200NTU, it has little influence on the determination result of total phosphorus, with the relative deviation within 5% and less than the allowable relative deviation of 10%. When the chromaticity of the water sample is less than 50 degrees, the influence on the determination result of total phosphorus is small, and the relative deviations are all within 10%.展开更多
基金This work was supported by the National Basic Research Program of China (2003CB415002) and the China Postdoctoral Science Foundation (No. 2003033486) and the Natural Science Research Fund of University in Jiangsu (04KJB150149)
文摘Sixteen indole derivatives have been computed at B3LYP/6-31 IG^＊＊ level using density functional theory （DFF）. Based on linear solvation energy theory, the structural parameters were employed to present correlation between the parameters of chromatograph capacity factor （CCF） and molecular structural parameters. As a result, the correlation equation of the reversed phased high performance liquid chromatograph capacity factor to the intercept lgk＇w and slope S of CCF were obtained, from which the correlation coefficients of lgk＇w to the structural parameters are r^2 = 0.9596 and q^2 = 0.9262. While the correlation coefficients of the parameter S r^2 q^2 with structures are = 0.9750 and = 0.9252. Moreover, the effect of water as solvent on the present two models was also considered using SCRF method, and the result shows that the predicting capacity of correlation equation of lgkw＇ increases, while that of the model for S decreases slightly. Both two correlation equations achieved in this work are more advantageous than those using theoretical descriptors from molecular connectivity indices.
文摘The chroma difference(DC) and lightness difference (DL) of 288 jadeite-jades with fine texture and even green color have been analyzed based on color difference formula CIE LAB in the uniform color space CIE 1976 L^~*a^~*b^~* to evaluate their contribution to the color appearance and color difference(DE).The analysis of lightness(L^~*), chroma(C^~*) and hue-angle(h_o) show that the vivid yellowish green color occurs when L^~*∈5.29-59.2,
基金Supported by the National Natrual Science Foundation of China
文摘The present paper covers the actional mechanism of trifluoroacetic acid for the separation of biopolymers investigated by using the parameters of stoichiometric displacement model for retention(SDM-R) in reversed-phase liquid chromatography. It was found that the trifluoroacetic acid(TFA) may participate in, or stimulate the association among displacing agent molecules in mobile phase, and decrease the affinity of both the associate molecules of the displacing agent and the TFA-protein ion-pairing. The former dominates over the separation selectivity of biopolymers as the concentration of TFA is lower than a given value, and the two contrary functions partly offset to each other and the latter dominates as its concentration is greater than the given value.
文摘Total phosphorus is an important index for surface water evaluation. Surface water presents certain turbidity and chromaticity due to its silt, plankton, inorganic substances and organic substances. At present, the determination of total phosphorus in the laboratory is mostly by spectrophotometry. Therefore, it is of great significance to explore the influence of chromaticity and turbidity on the determination of total phosphorus in the laboratory. In this paper, different concentrations of total phosphorus solution are selected to analyze the influence of chromaticity and turbidity on total phosphorus respectively. The experimental results show that when the turbidity of water sample is less than 200NTU, it has little influence on the determination result of total phosphorus, with the relative deviation within 5% and less than the allowable relative deviation of 10%. When the chromaticity of the water sample is less than 50 degrees, the influence on the determination result of total phosphorus is small, and the relative deviations are all within 10%.
