Autonomy under the Shade of Governmental Control:the Bao-Jia System in Hangzhou Area after the War;

A Micro Analysis of Population and Family in Jiangnan Area in Late 1940s——centered on Baojia population registers data

In the Qing Dynasty, head of Baojia is generally called Dibao, and its key duties undergo great changes,which is related to change of duties when Lijia is developed into Baojia since the period of the regimes of Emperor Yongzheng and Qianlong.

The Improvement on the Technology Process of Compounding CPDA;

Aiming at the serious casing corrosion of water injection wells,one chemical agent is injected into the annular space of the tubing and casing,and forms a ring-shape elastical seal plug,then the suitable corrosion control agent and bactericidal agent are injected,used as a casing protection fluid.