Anew structure of machine travelling valve for slant well pumping is pro-posed and the work principle of the valve is presented.

Final Castle——Contrary Architectural Notes in the Move Times;

Recurrence of random walks in an independent environment on a halfline;

Property of random walk in time random environments on the line;

Using the random walk model to describe the intervals of feeding ends in the fixed size reeling process,we proved the distribution of intervals of feeding ends is a Gamma distribution through the characteristic function.

Community of Zooplankton and Assessment to Water Quality in Bohai Bay;

The Situation and relation of mycrophyte,zooplankton and fish in the ecological restoration of a tropical shallow lake in a city;

Effect of zooplankton on removing algae in bio-manipulation;