Ten novel 5-substituted derivatives of 3-（1-hydroxyethylidene）pyrrolidine-2,4-dione were synthesized. The compounds were confirmed by IR, 1H NMR, MS and elemental analysis. The bioassay indicated that these compound...Ten novel 5-substituted derivatives of 3-（1-hydroxyethylidene）pyrrolidine-2,4-dione were synthesized. The compounds were confirmed by IR, 1H NMR, MS and elemental analysis. The bioassay indicated that these compounds showed noticeable herbicidal activities, and compounds 6f and 6j exhibited excellent inhibitory activities against the stalk of Echinochloa crusgalli, with ECso values of 94.4 and 72.7 rag/L, respectively.展开更多
In this paper, we obtain a constraint of the mean curvature for proper biharmonic submanifolds in a sphere. We give some characterizations of some proper biharmonic submanifolds with parallel mean curvature vector in ...In this paper, we obtain a constraint of the mean curvature for proper biharmonic submanifolds in a sphere. We give some characterizations of some proper biharmonic submanifolds with parallel mean curvature vector in a sphere. We also construct some new examples of proper biharmonic submanifolds in a sphere.展开更多
We consider the inverse curvature flows of smooth,closed and strictly convex rotation hypersurfaces in space forms M_(κ)^(n+1)with speed function given by F^(-α),whereα∈(0,1]forκ=0,-1,α=1 forκ=1 and F is a smoo...We consider the inverse curvature flows of smooth,closed and strictly convex rotation hypersurfaces in space forms M_(κ)^(n+1)with speed function given by F^(-α),whereα∈(0,1]forκ=0,-1,α=1 forκ=1 and F is a smooth,symmetric,strictly increasing and 1-homogeneous function of the principal curvatures of the evolving hypersurfaces.We show that the curvature pinching ratio of the evolving hypersurface is controlled by its initial value,and prove the long time existence and convergence of the flows.No second derivatives conditions are required on F.展开更多
基金supported by the National High-Tech R&D Program of China(863 Program,No. 2011AA10A206)the National Key Technologies R&D Program of China(No.2011BAE06B04)
文摘Ten novel 5-substituted derivatives of 3-（1-hydroxyethylidene）pyrrolidine-2,4-dione were synthesized. The compounds were confirmed by IR, 1H NMR, MS and elemental analysis. The bioassay indicated that these compounds showed noticeable herbicidal activities, and compounds 6f and 6j exhibited excellent inhibitory activities against the stalk of Echinochloa crusgalli, with ECso values of 94.4 and 72.7 rag/L, respectively.
基金supported by National Natural Science Foundation of China (Grant No.10701007)
文摘In this paper, we obtain a constraint of the mean curvature for proper biharmonic submanifolds in a sphere. We give some characterizations of some proper biharmonic submanifolds with parallel mean curvature vector in a sphere. We also construct some new examples of proper biharmonic submanifolds in a sphere.
基金Supported by the National Key R and D Program of China(Grant No.2020YFA0713100)National Natural Science Foundation of China(Grant Nos.11971244 and 11871283)+1 种基金Natural Science Foundation of Tianjin,China(Grant No.19JCQNJC14300)Research(Grant No.KY0010000052)from University of Science and Technology of China。
文摘We consider the inverse curvature flows of smooth,closed and strictly convex rotation hypersurfaces in space forms M_(κ)^(n+1)with speed function given by F^(-α),whereα∈(0,1]forκ=0,-1,α=1 forκ=1 and F is a smooth,symmetric,strictly increasing and 1-homogeneous function of the principal curvatures of the evolving hypersurfaces.We show that the curvature pinching ratio of the evolving hypersurface is controlled by its initial value,and prove the long time existence and convergence of the flows.No second derivatives conditions are required on F.
