Papers by Keyword: Triangle

Abstract: 4H-SiC homo-epitaxial films were grown using a high speed wafer rotation vertical CVD tool, and effects of wafer rotation speed during initial temperature ramping before epitaxial growth were investigated. Also, the effects of conditions during growth of the highly doped buffer layer on both surface and PL defect densities were investigated. It was found that the wafer rotation speed during the temperature ramping has a large influence on the surface defect density of the films. Especially, triangles generated from small pits were considerably reduced in the samples grown at a higher wafer rotation speed during the temperature ramping. The phenomena could be explained as a result of suppressed interfacial reaction between down-falls (DFs) and the wafer surface. Additionally, it was found that the density of basal plane dislocations (BPDs) on a drift layer is remarkably reduced by adjusting the C/Si ratio during growth of the buffer layer grown prior to the drift layer. By applying higher wafer rotation speed during the temperature ramping and optimizing the C/Si ratio for the growth of the buffer layer, a total defect density of 0.75 cm^-2 on the film, which includes DFs, triangles, DF-triangles, stacking faults (SFs) and BPDs, was achieved.

Abstract: An algorithm for triangle interpolation on discrete points is presented in the paper. It creates a square mesh which covers all the discrete points, then puts the points into the mesh and records the relationship between grids and points. When interpolating elevation of an interpolation point, it can fast find the discrete points which are near the interpolation point and these discrete points can be used to create a special triangle which contains the interpolation point. The elevation of the interpolation point can be obtained from the triangle. The method has the advantage of fast speed, high precision and needing less memory.

Abstract: To render terrain realistically and efficiently, we firstly introduce projected grid to construct terrain coarse meshes. Projected grid uses longest edge bisection, taking advantages of fracture eliminating, to implement triangle subdivision. To realize adaptive refinement of terrain coarse meshes, we introduce the concept of bounding sphere and the idea of unsaturated error metric, design GPU unsaturated error metric based on bounding sphere, in order to implement terrain LOD modeling finally. Experimental results show that projected grid avoids culling and improves the speed of terrain rendering, GPU unsaturated error metric can select terrain coarse meshes nodes accurately, reduce triangles number and keep terrain feature. As a result, the algorithm can achieve a high FPS and a good visual effect, implement terrain real-time rendering.

Abstract: Copper nanorods and triangular nanoplates have been successfully generated by via a simple solution-phase approach by reducing CuCl2 with L-ascorbic acid (AsA) in aqueous solution in the presence of cetyltgrimethlammonium bromide (CTAB). The formation of self-assembled microstructures of CTAB molecules in aqueous solution is suggested to account for the anisotropic growth of one-dimensional copper nanorods and triangular nanoplates.