Aim: To characterize esophageal papillae hyperproliferation (papillae density and up growth) and its relationship with esophageal lesions in symptom free subjects from the high and low incidence areas for esophageal cancer and to expand the knowledge for morphological changes in early stage of esophageal carcinogenesis.

Autolisp,a computer aid design language,is applied to realize the parametric design of bionic bit The design of bit distribution,waterways and steel body will be finished through the analysis and calculations of parameters by the expert system in computer.

Combined with teaching practice,this article summarizes the purpose and request of human head sketching,expounding the structural feature and proportional relationship of the head,the color and material of the head portraits,as well as the essentials,the concrete steps and cautions in painting.