ally paid more attention to the insertion algorithms for points and edges, but little to the deletion algorithms. The presented algorithms are far insufficient for the dynamic updating of CD-TIN. In this paper, the constraint edge in CD-TIN is considered to be any set of broken lines, i.e., polygon edges, broken lines and simple segments. The constraint edge may be composed of one or more constraint segments, and it is allowed to be in any form: Open or close, intersection or self-intersection. By improving to present insertion and deletion algorithms for D-TIN, two new algorithms for CD-TIN updating are presented. According to the polymorphism of the constraints in CD-TIN, virtual point is adopted to represent the crossing node between constraint edges when a constraint edge is inserted in CD-TIN. Two new algorithms named as Integral Ear Elimination (IEE) and Influence Domain Retriangulation for Virtual Point (IDRVP) are presented, the former is for constraint point deletion, while the later is for the insertion and deletion of constraint edge. The principle of IDRVP is that to divide the influence domain of a virtual point into some parts by the constraint-keeping edges, and to retriangulate each part of the influence domain individually referring to the constraint visible property and constraint empty circle (CEC) criterion. Finally, a prototype system is developed with VC++, one case on the integration of 3D terrain and buildings is demonstrated to test the correctness of new algorithms. It shows that the new algorithms are effective for 136 WU LiXin et al.

Peripheral nerve injury (PNI) exists widely and seriously affects patients' daily lives.However, the effect of nerve repair is still limited, and only 50% of patients can recover useful functions. To overcome these obstacles, collagen-coated poly(lacticco-glycolic acid) (PLGA) conduits loaded with CBD-IGF-1 were designed and tested in vitro and in vivo. The physical characterization of the conduit was tested by scanning electron microscopy, and the static water contact angle, release rate, and nerve regeneration ability of the conduit were verified in a rat sciatic nerve injury model.

The Composite based on CIIR and variable sulfur/accelerator ratio were prepared by compounding and vulcanizing process. Tensile properties and dynamic mechanical properties of CIIR were studied. The results indicate that tensile strength and loss factor are influenced by sulfur/ accelerator ratio. Tensile strength and modulus are improved with increasing sulfur/accelerator ratio while loss factor decrease with increasing sulfur/ accelerator ratio.

The strength of gravel soil of Yili’s First Mine in different water contents was studied by multifunction static and dynamic triaxial test machine. The results show that （1）The yield limit decreases with the increasing of water content under steady confining pressure, and the greater the confining pressure, the greater the yield point of its axial in the same moisture conditions. （2）The expansion becomes into contraction with increasing moisture content. （3）Strength index of gravel soil becomes smaller with the increase of moisture content. The relationship between friction angle and water contents is . And the relationship between cohesion (or bite force) and water contents is . The results provide a theoretical basis for shaft design and construction of Yili’s First Mine.