• 제목/요약/키워드: Mesh Surface

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An Efficient Polygonal Surface Reconstruction (효율적인 폴리곤 곡면 재건 알고리즘)

  • Park, Sangkun
    • Journal of Institute of Convergence Technology
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    • v.10 no.1
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    • pp.7-12
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    • 2020
  • We describe a efficient surface reconstruction method that reconstructs a 3D manifold polygonal mesh approximately passing through a set of 3D oriented points. Our algorithm includes 3D convex hull, octree data structure, signed distance function (SDF), and marching cubes. The 3D convex hull provides us with a fast computation of SDF, octree structure allows us to compute a minimal distance for SDF, and marching cubes lead to iso-surface generation with SDF. Our approach gives us flexibility in the choice of the resolution of the reconstructed surface, and it also enables to use on low-level PCs with minimal peak memory usage. Experimenting with publicly available scan data shows that we can reconstruct a polygonal mesh from point cloud of sizes varying from 10,000 ~ 1,000,000 in about 1~60 seconds.

Medial Surface Generation by Using Chordal Axis Transform in Shell Structures (쉘 구조물에서 Chordal Axis Transform 을 이용한 중립면 생성)

  • 권기연;박정민;이병채;채수원
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.865-870
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    • 2004
  • This paper describes the generation of chordal surface for various shell structures, such as automobile bodies, plastic injection mold components and shell metal parts. After one-layered tetrahedral mesh is generated by an advancing front algorithm, the chordal surface is generated by cutting a tetrahedral element. It is generated one or two elements at a tetrahedral element and the chordal surface is composed with triangular or quadrilateral elements. This algorithm has been tested on several models with rib structure.

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Fabrication of Stable Water/Oil Separation Filter Using Effect of Surface Wettability (표면 젖음성을 이용한 물/오일 분리막 제작)

  • Kim, Dohyeong;An, Taechang
    • Journal of Sensor Science and Technology
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    • v.25 no.3
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    • pp.213-217
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    • 2016
  • The superhydrophobic and superoleophobic meshes surfaces have been used in various applications such as self-cleaning, anti-icing, gas exchange, oil-water separation, sound-wave penetrable anti-wetting structures, etc. In particular, there are many studies for oil-water separation with environmental issues. Because of high pressure and dynamic environment, oil-water separation filters must have stable surface properties as super-hydrophobicity and superoleophobicity. The oleophobicity of surface depends on the surface chemistry and roughness of the surface. The roughness of oleophobic surface enhances its static contact angle and stability. The multi-scale hierarchical structure provides a stable superhydrophobic state by maintaining a Cassie state. In this research, we fabricated a superoleophobic mesh with a multi-scale hierarchical structure to increase the pressure resistance and adjusted a size of the mesh hole.

Pulse reverse current 을 이용한 Cu mesh 도금의 표면형상 개선

  • Lee, Jin-Hyeong;Lee, Ju-Yeol;Kim, Man
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2009.05a
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    • pp.136-137
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    • 2009
  • 전자파 차폐재로 메쉬를 제작하는 기존의 배치 방식은 복잡한 작업공정과 비싼 설비로 인해 생산원가 높다. 그래서 pulse reverse current를 이용하여 Cu mesh 도금을 하였다. 정펄스의 전류밀도가 $31mA/cm^2$일일 때 역펄스의 전류밀도 및 duty cycle에 상관없이 표면은 매끄럽게 나왔다. 정펄스의 전류밀도가 $454mA/cm^2$일때는 duty cycle이 25%이하는 표면상태가 매끄럽게 나타났지만 33%이상에서 표면상태가 거칠게 도금이 되었다.

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Surface Modification of Screen-Mesh Wicks to Improve Capillary Performance for Heat Pipes (히트파이프 모세관 성능 개선을 위한 스크린-메쉬 윅의 표면 개질)

  • Jeong, Jiyun;Lim, Hyewon;Kim, Hyewon;Lee, Sangmin;Kim, Hyungmo
    • Tribology and Lubricants
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    • v.38 no.5
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    • pp.185-190
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    • 2022
  • Among the operating limits of a heat pipe, the capillary limit is significantly affected by the characteristics of the wick, which is determined by the capillary performance. The major parameters for determining capillary performance are the maximum capillary pressure and the spreading characteristics that can be expected through the wick. A well-designed wick structure improves capillary performance and helps improve the stability of the heat pipe by enhancing the capillary limit. The capillary performance can be improved by forming a porous microstructure on the surface of the wick structure through surface modification techniques. In this study, a microstructure is formed on the surface of the wick by using a surface modification method (i.e., an electrochemical etching process). In the experiment, specimens are prepared using stainless-steel screen mesh wicks with various fabrication conditions. In addition, the spreading and capillary rise performances are observed with low-surface-tension fluid to quantify the capillary performance. In the experiments, the capillary performance, such as spreading characteristics, maximum capillary pressure, and capillary rise rate, improves in the specimens with microstructures formed through surface modification compared with the specimens without microstructures on the surface. The improved capillary performance can have a positive effect on the capillary limit of the heat pipe. It is believed that the surface microstructures can enhance the operational stability of heat pipes.

Triangular Mesh Generation using non-uniform 3D grids (Non-uniform 3D grid를 이용한 삼각형망 생성에 관한 연구)

  • 강의철;우혁제;이관행
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1283-1287
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    • 2003
  • Reverse engineering technology refers to the process that creates a CAD model of an existing part using measuring devices. Recently, non-contact scanning devices have become more accurate and the speed of data acquisition has increased drastically. However, they generate thousands of points per second and various types of point data. Therefore. it becomes a important to handle the huge amount and various types of point data to generate a surface model efficiently. This paper proposes a new triangular mesh generation method using 3D grids. The geometric information of a part can be obtained from point cloud data by estimating normal values of the points. In our research, the non-uniform 3D grids are generated first for feature based data reduction based on the geometric information. Then, triangulation is performed with the reduced point data. The grid structure is efficiently used not only for neighbor point search that can speed up the mesh generation process but also for getting surface connectivity information to result in same topology surface with the point data. Through this integrated approach, it is possible to create surface models from scanned point data efficiently.

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Measurement of the Particle Current Changes Associated with the Flatness of Deflector Mesh Surface in Particle Beam Mass Spectrometer System

  • Kim, Dongbin;Kim, TaeWan;Jin, Yinhua;Mun, Jihun;Lim, In-Tae;Kim, Ju-Hwang;Kim, Taesung;Kang, Sang-Woo
    • Applied Science and Convergence Technology
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    • v.25 no.2
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    • pp.25-27
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    • 2016
  • The surface flatness of metal meshes in a deflector of particle beam mass spectrometer (PBMS) required ideally flat, and this can specify the particle trajectories which goes through the detector. In this research, charged particle current was measured using the different surface roughness deflectors. NaCl particles were generated monodispersed in its size by using differential mobility analyzer and the whole processes were followed the way calibrating PBMS. The results indicate that the mesh surface morphology in the deflector can affect to the particle size and the concentration errors, and sensitivity of PBMS.

A study on the improvement of impregnation on the surface of injection-molded thermoplastic woven carbon fabric composite (열가소성 직물탄소복합소재 사출 성형품의 표면 함침 개선에 관한 연구)

  • Jeong, Eui-Chul;Yoon, Kyung-Hwan;Lee, Sung-Hee
    • Design & Manufacturing
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    • v.15 no.3
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    • pp.39-44
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    • 2021
  • In molding of continuous fiber-reinforced thermoplastic composites, it is very difficult to impregnate between the reinforcements and the matrix since the matrix has a high melting temperature and high viscosity. Therefore, most of composite molding processes are divided in the manufacturing processes of intermediate materials called prepreg and the forming of products from intermediate materials. The divided process requires additional facilities and thermoforming, and they increase the cycle time and cost of composite products. These problems can be resolved by combining the continuous fiber-reinforced composite molding process with injection molding. However, when a composite material is manufactured by inserting woven fabric into the injection mold, poor impregnation occurs on the surface of the molded product. It affects the properties of the composites. In this paper, through an impregnation experiment using cores with different heat transfer rates and pore densities, the reason for the poor impregnation was confirmed, and molding experiments were conducted to produce composite with improved surface impregnation by inserting the mesh. And also, the surface impregnation and deformation of composites molded using different types of mesh were compared with each other.

Geometric Snakes for Triangular Meshes (삼각 메쉬를 위한 기하학 스네이크)

  • Lee, Yun-Jin;Lee, Seung-Yong
    • Journal of the Korea Computer Graphics Society
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    • v.7 no.3
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    • pp.9-18
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    • 2001
  • Feature detection is important in various mesh processing techniques, such as mesh editing, mesh morphing, mesh compression, and mesh signal processing. In this paper, we propose a geometric snake as an interactive tool for feature detection on a 3D triangular mesh. A geometric snake is an extension of an image snake, which is an active contour model that slithers from its initial position specified by the user to a nearby feature while minimizing an energy functional. To constrain the movement of a geometric snake onto the surface of a mesh, we use the parameterization of the surrounding region of a geometric snake. Although the definition of a feature may vary among applications, we use the normal changes of faces to detect features on a mesh.

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Highly Flexible Dye-sensitized Solar Cell Prepared on Single Metal Mesh

  • Yun, Min Ju;Cha, Seung I.;Seo, Seon Hee;Lee, Dong Y.
    • Current Photovoltaic Research
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    • v.2 no.3
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    • pp.79-83
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    • 2014
  • Dye-sensitized solar cells (DSSCs) are applied in the emerging fields of building integrated photovoltaic and electronics integrated photovoltaic like small portable power sources as demands are increased with characteristic advantages. Highly flexible dye-sensitized solar cells (DSSCs) prepared on single stainless steel mesh were proposed in this paper. Single mesh DSSCs structure utilizing the spraying the chopped glass paper on the surface treated stainless steel mesh for integrating the space element and the electrode components, counter electrode component and photoelectrode component were coated on each side of the single mesh. The fabricated single mesh DSSCs showed the energy-conversion efficiency 0.50% which show highly bendable ability. The new single mesh DSSCs may have potential applications as highly bendable solar cells to overcome the limitations of TCO-based DSSCs.