A point in this abundance coordinate system could define the swallow form curve of the chondrite normalized REE patterns on the basis of eight quadrants where the point of the REE abundance distri.

This paper presents the method for drawing implicit curves that uses many short segments to trace,cross and draw implicit curves by working out crossing points through division.

The general way of solving the problem how to compute the minimum distance from a point to a implicit curve or surface is by the searching algorithm,like the optimization algorithm in mathematic programming.

A new method for closed curve construction is introduced, which is based on the combination of RBF (radial basis function) neural network and the principle of implicit curve construction.

NC Programming on formula curve is achieved by editor,DXF and AutoCAD,The method is introduced in detail.

gives a specific example for parts,This paper introduce the two ways of macro programming of formula curve for fanucoi CNC lathe system,and Comparethe two methods.

For accurately drawing formula curve and surface in AutoCAD surrounding,this paper uses the powerful function operation and computing function to compute a series of coordinate values on the formula curve and surface.

Based on the stem profile model for Pinus tabulaeformis which was developed recently,the article studied its fitness for the following 5 species;T Abies fargesii,Betula albosinensis,Betula utilis,Quercus aliena and Quercus varabilis.