A new heterocyclic compound,named 5,5 -diisobutoxy-2,2 -bifuran(1),and four known compounds(2-5) were isolated from the roots of Cyathula officinalis Kuan.Their structures were elucidated by spectroscopic methods.Amon...A new heterocyclic compound,named 5,5 -diisobutoxy-2,2 -bifuran(1),and four known compounds(2-5) were isolated from the roots of Cyathula officinalis Kuan.Their structures were elucidated by spectroscopic methods.Among these compounds,5,5 - dibutoxy-2,2 -bifuran(2) was isolated for the first time from this plant.展开更多
The Reynolds number effect of the interaction between the three-dimen-sional ship stern with multi-propellers and its corresponding hydrodynamic performance under four different orders of the Reynolds number (includin...The Reynolds number effect of the interaction between the three-dimen-sional ship stern with multi-propellers and its corresponding hydrodynamic performance under four different orders of the Reynolds number (including the full scale Reynolds number 1. 67×109 and the model scale Reynolds number 1. 67×106) are numerically investigated in this paper. This approach to propeller-hull interaction is based on three-di-mensional unsteady RANS equations coupled with a propeller performance program in an interactive and iterative manner to predict the combined flow field and hydrodynamic per- formance of propeller. By comparing the computed effective wake distribution and fraction under four different orders of the Reynolds number, the scale effect of nominal and effec-tive wake distribution is examined and discussed.展开更多
基金the Natural Science Foundation of Tianjin(No.06YFJMJC15800) for the financial support.
文摘A new heterocyclic compound,named 5,5 -diisobutoxy-2,2 -bifuran(1),and four known compounds(2-5) were isolated from the roots of Cyathula officinalis Kuan.Their structures were elucidated by spectroscopic methods.Among these compounds,5,5 - dibutoxy-2,2 -bifuran(2) was isolated for the first time from this plant.
文摘The Reynolds number effect of the interaction between the three-dimen-sional ship stern with multi-propellers and its corresponding hydrodynamic performance under four different orders of the Reynolds number (including the full scale Reynolds number 1. 67×109 and the model scale Reynolds number 1. 67×106) are numerically investigated in this paper. This approach to propeller-hull interaction is based on three-di-mensional unsteady RANS equations coupled with a propeller performance program in an interactive and iterative manner to predict the combined flow field and hydrodynamic per- formance of propeller. By comparing the computed effective wake distribution and fraction under four different orders of the Reynolds number, the scale effect of nominal and effec-tive wake distribution is examined and discussed.
