This article introduces the equipment used for helium mass spectrometer leak test for the welds of tube and tube-sheet when using hood technique,the connection of the system,operational flow of the test and the calculating method of the leakage rate.

Straw stalk s plastic mulching technique is a technique with largest increase in yield and long lasting time in current dry farming industry.

The mulching technique can increase 2.

It may be used to correctly evaluate the capabilities of drought resistant of purple soils and different mulch techniques.

In order to prove the effects of different varieties and main covering technique on yield and quality of tobacco, and give some message for tobacco production in Wuping.