This paper introduces the computerized calculation principle of the water surface curve of the open-channel constant gradual flow, including three solving processes of the critical water-depth hk, the normal water-depth ho an d the actual water-depth h of the water surface curve, puts forward the calcula tion principle and calculation diagram of each process, and makes brief outcome analysis.

According to the characters of abrupt change and gradual change,a twice difference based method and a window-difference maximum based method are proposed for abrupt change detection and gradual change detection separately.

Illustrated by some existing buildings,it is manifested that city architecture-the solidified music-shows the rhythm and cadence of continuity,gradual change,waving and overlapping,and therefore offers us the sense of artistic pleasure and enjoyment.

Although they lived in different ages and nations, Lenin and Deng Xiaoping held the identical idea about gradual change of economic system-the necessity of establishing economic system, how to start the gradual change and how to push the gradual change forward in a all-round way, etc.