Aim: To characterize the prevalence of gastric cardia lesions, to correlate these lesions with sex and age through mass survey on 1 975 symptom free subjects from the high and low incidence area and to expand the knowledge on morphological changes in multistage carcinogenesis of gastric cardia adenocarcinoma (GCA).

Aim: To further characterize the prevalence of different precancerous lesions and to correlate these observation with sex and age through mass survey at high and low incidence area in Henan.

Aim: To characterize the changes of retinoic acid receptor β (RARβ) expression in esophageal precancerous and cancerous lesions from the subjects at high and low incidence areas for esophageal cancer in Henan.

In order to increase launching opportunities of ship-to-air missile intercepting the low-altitude target, launching area low boundary of ship-to-air missile guided by ship-borne helicopter and warship coordination was researched.