Papers by Author: Xian Guo Cheng

Abstract: The paper analyzed soil water evaporation variation of spring maize under film and straw mulching. The evaporation had the character of higher at early period and telophase, and lower in the middle. The soil water evaporation was significant different at different mulching material between before and after heading stage. It built an estimation method to cumulative soil water evaporation with spring maize height, and the model could product soil water evaporation early.

Abstract: This paper presents an efficient method for deforming B-spline surfaces, based on the surface energy minimization. Firstly, using an analogy between the B-spline surface patch and the thin-plate element of the finite element method, and applying external forces on the surface with some given geometric constraints, the forces can locate on part of the surface or the surface. Then, the energy of the B-spline surface can change with the change of the forces. Finally, a new B-spline surface is generated by solving an optimization problem of change of the energy. The forces can be a single force, a distributed force and set of isolated force. The method can accomplish easily local deformation and total deformation of the B-spline surface.