http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
General 3D Offsetting of a Triangular Net Using an Implicit Function and the Distance Fields
유동진 한국정밀공학회 2009 International Journal of Precision Engineering and Vol. No.
A novel approach which uses the distance fields based on cell subdivision and an implicit surface interpolation based on the radial basis function is proposed in order to get an accurate and error-free offset model of arbitrary shapes composed of a large number of triangle meshes. In the method, the space bounding the original model is divided into smaller cells. For the efficient calculation of distance fields, valid cells which will generate a portion of offset model are selected previously by the proposed detection algorithm. These valid cells are divided again into much smaller voxels which assure required accuracy. At each voxel, the distance fields are created by calculating the minimum distances between the corner points of voxels and the triangle meshes. For the more efficient calculation of distance fields, valid vertices among the triangle meshes which will generate minimum distances with current cell are selected by checking the intersection between current cell and a cone prism generated at each vertex of triangle meshes. In addition, a new approach based on an implicit surface interpolation scheme is proposed to perform two types of offsetting operations including uniform and non-uniform offsetting in the same framework. In the method, a smooth implicit surface is generated from the discrete offset distance values given by the user. After generating the whole distance fields, the offset surface was constructed by using the conventional marching cube algorithm together with mesh smoothing scheme. The effectiveness and validity of this new offset method was demonstrated by performing numerical experiments for the various types of triangle meshes.
유동진,김광혁 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.9
Additive manufacturing (AM) method has been a promising technique to produce three-dimensional (3D) tissue engineering scaffolds comprised of complex pore morphologies. Multi-functional scaffolds fabricated through AM techniques can provide outstanding combinations of mechanical and biological properties including stiffness, strength, toughness, and fluidic permeability. Among the various scaffold design methods, the pore morphology based on triply periodic minimal surface (TPMS) has been of great interest to many researchers due to its easy and accurate controllability on design parameters such as pore size, pore shape, volume fraction, and inner channel interconnectivity. In this paper, we propose a new multi-morphology scaffold design algorithm for building a wide variety of complex hybrid scaffolds composed of multiple TPMS morphologies and arbitrarily-shaped transition boundaries within one scaffold using the volumetric distance field (VDF) and the beta growth function (BGF). Through a variety of design results, we demonstrate the potential to design highly complex and heterogeneous scaffolds with enhancements in stiffness, strength, and permeability. In the method, the resulting scaffold hybrid morphology can be easily and accurately controlled to systematically explore a multitude of transition pore morphologies thereby enabling the optimization of multi-functional properties such as a combination of a high mechanical stiffness together with a high biological diffusion rate.
유동진 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.10
New bispsoralen derivatives 5-10, 8-MOP-NHCO(CH2)nCONH-8-MOP (BPSBA-Cn, n = 0, 1, 2, 3, 4 and 5) in which 5 position of an 8-methoxypsoralen (8-MOP) is linked by various lengths of bisamide polymethylene chain to 5 position of the other 8-MOP, have been synthesized by the amidation of 5-amino-8-methoxypsoralen (12) with a,w -alkanoyl dichloride. Photophysical properties of their derivatives including p-p stacking interaction between the two aromatic moieties were investigated by UV absorption and fluorescence emission spectra. Efficient ring-ring stacking interactions have been observed in BPSBA-C4 (9) from the percent hypochromism (%H) of the models.