By means of a logarithm law for the velocity profile, a corrected formula of bed resistance coefficient, which involves many factors such as gradient of still water depth, variation of surface elevation, flow directio...By means of a logarithm law for the velocity profile, a corrected formula of bed resistance coefficient, which involves many factors such as gradient of still water depth, variation of surface elevation, flow direction, and so on, is derived from the 3D governing equations of tidal current by averaging over the whole water depth. Theoretical analysis and application have shown that the 2D plane tidal current numerical model would be more reasonable and could be applied to steep bottom topography when the corrected bed resistance coefficient is used, therefore the results of reproduction simulation and engineering calculation would be more scientific and reasonable.展开更多
[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenolic acids,salvianolic acid B,tanshinol,lithospermic acid a...[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenolic acids,salvianolic acid B,tanshinol,lithospermic acid and rosmarinic acid in Radix Salviae Miltiorrhizae by HPLC and conduct methodological investigation.[Methods]Salvianolic acid B,with moderate retention time,good resolution,great response value and easy availability was selected as the internal standard,and the relative retention values and relative correction factors between tanshinol,rosmarinic acid,lithospermic acid and salvianolic acid B were established.The results of QAMS were compared with those of external standard method to verify the accuracy and applicability of QAMS.[Results]There were no significant differences between the calculated values of QAMS and the measured values of external standard method.The relative deviation was less than 3%,and the relative correction factors obtained from the experiment were credible.[Conclusions]QAMS can be used to determine the contents of phenolic acids in Radix Salviae Miltiorrhizae formula granules.展开更多
为改善机场能见度的预报准确性,使其更加贴合民航业务运行,基于GRAPES_RAFS数值预报系统,利用Stoelinga Warner(SW)、SW-V1、Rapid Update Cycle (RUC)、Forecast Systems Laboratory(FSL)、Air Force Weather Agency(AFWA)、AFWA-FSL(A...为改善机场能见度的预报准确性,使其更加贴合民航业务运行,基于GRAPES_RAFS数值预报系统,利用Stoelinga Warner(SW)、SW-V1、Rapid Update Cycle (RUC)、Forecast Systems Laboratory(FSL)、Air Force Weather Agency(AFWA)、AFWA-FSL(A-F)等6种能见度诊断方法计算38个千万级机场的能见度,并与机场例行天气报告进行比较,分析平均相对误差和平均绝对误差,得出适用于机场的能见度诊断方法。结果表明:RUC和A-F方法的诊断结果较其他方法好;同时考虑标准差,A-F方法诊断结果更稳定,优于RUC方法。最后,以各机场A-F方法的MRE作为修正项,得出A-F方法的修正公式,对于不同类型的机场可进行相应的修正。展开更多
基金National Natural Science Foundation of China(Grant No.49971064)
文摘By means of a logarithm law for the velocity profile, a corrected formula of bed resistance coefficient, which involves many factors such as gradient of still water depth, variation of surface elevation, flow direction, and so on, is derived from the 3D governing equations of tidal current by averaging over the whole water depth. Theoretical analysis and application have shown that the 2D plane tidal current numerical model would be more reasonable and could be applied to steep bottom topography when the corrected bed resistance coefficient is used, therefore the results of reproduction simulation and engineering calculation would be more scientific and reasonable.
基金Supported by High-level Entrepreneurial and Innovative Talent(Team)Project 2015.
文摘[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenolic acids,salvianolic acid B,tanshinol,lithospermic acid and rosmarinic acid in Radix Salviae Miltiorrhizae by HPLC and conduct methodological investigation.[Methods]Salvianolic acid B,with moderate retention time,good resolution,great response value and easy availability was selected as the internal standard,and the relative retention values and relative correction factors between tanshinol,rosmarinic acid,lithospermic acid and salvianolic acid B were established.The results of QAMS were compared with those of external standard method to verify the accuracy and applicability of QAMS.[Results]There were no significant differences between the calculated values of QAMS and the measured values of external standard method.The relative deviation was less than 3%,and the relative correction factors obtained from the experiment were credible.[Conclusions]QAMS can be used to determine the contents of phenolic acids in Radix Salviae Miltiorrhizae formula granules.
文摘为改善机场能见度的预报准确性,使其更加贴合民航业务运行,基于GRAPES_RAFS数值预报系统,利用Stoelinga Warner(SW)、SW-V1、Rapid Update Cycle (RUC)、Forecast Systems Laboratory(FSL)、Air Force Weather Agency(AFWA)、AFWA-FSL(A-F)等6种能见度诊断方法计算38个千万级机场的能见度,并与机场例行天气报告进行比较,分析平均相对误差和平均绝对误差,得出适用于机场的能见度诊断方法。结果表明:RUC和A-F方法的诊断结果较其他方法好;同时考虑标准差,A-F方法诊断结果更稳定,优于RUC方法。最后,以各机场A-F方法的MRE作为修正项,得出A-F方法的修正公式,对于不同类型的机场可进行相应的修正。
