Now etching has be-come the standard technology,and etching equipment is the key equipment in IC production.

In this paper the principle ,construction and the mechanics generated by double frequency of the laser double-frequency interferometer were analysed , then the actual application of the laser double-frequency interferometer in Lithography equipment was formulated.

Reasons for equipment corrosion in brine process and precautionary measures;

For equipment corrosion in the wet desulphurization system in ammonia synthesis industry, this article gives a brief introduction, analyzes the reasons and forms.

ummarizes equipment corrosion and corrosion prevention experiences in processing continental mixed crude oil and imported high sulfur crude oil,emphasizing on the analysis of typical corrosion cases and preventive measures,and puts forward effective measures to solve equipment corrosion problem.