• 제목/요약/키워드: mesh form

검색결과 263건 처리시간 0.024초

The Effect of Tin Ion-plating on the Bond Strength of Orthodontic Bracket (TiN Ion-Plating이 교정용 브라켓의 접착강도에 미치는 영향)

  • KIM, Seok-Yong;KWON, Oh-Won;KIM, Kyo-Han
    • The korean journal of orthodontics
    • /
    • 제27권1호
    • /
    • pp.157-171
    • /
    • 1997
  • This study was conducted to see the effect of TiN ion-plating on the bond strength of orthodontic bracket. Three stainless-steel brackets with different base types were chosen; when TiN ion-plated brackets and non iorrplated brackets were bonded to the teeth, initial and long-term bond strength were measured, The observations oi bonding surface and failure sites through the scanning electron microscope were analysed and compared. The summary of this study was as follows; ${\cdot}$ When TiN ion-plating was not applied, the Micro-Loc type was the highest in bond strength atter 24 hours as $5.89{\pm}1.77$ MPa, followed by $4,27{\pm}1.12MPa$ for Foil Mesh type and $2.64{\pm}0.58MPa$ for Undercut type(P<0.05). ${\cdot}$ Under TiN ion-plating, the bond strength after 24 hours showed: Micro-Loc type $-6.26{\pm}1.51MPa$, Foil Mesh type $-7.45{\pm}2.01MPa$, Undercut type $-2.93{\pm}0.84MPa$. Unlike in the case of non ion-plating, Foil Mesh type showed a higher strength than Micro-Loc type, with Undercut type still showing the lowest bond strength(P<0.05). The bond strength, after 24 hours, increased in case of ion-plated in all 3 types, but a significant increase was shown only in Foil Mesh type(P<0.001). ${\cdot}$ Under a long-term immersion, regardless of ion or non ion-plating, bond strength in general increased over the initial bond strength(one day), with more stability. ${\cdot}$ Through scanning electron microscopic observation of bonding surface, it was found that, regardless of the bracket base type or the application of ion-plating, the resin was thoroughly spreaded into bracket base to form a solid bonding surface between the bracket and the tooth. This was also true in case of a long-term immersion. ${\cdot}$ The scanning electron microscopic observation of failure sites revealed diverse failure patterns.

  • PDF

A Study on the Composition of Silver Paste for Micro Nozzle Dispensing Method (미세노즐 토출에 적용 가능한 은 전극의 조성에 대한 연구)

  • Kim, Do-Hyung;Shin, Dong-Wook;Ryu, Sung-Soo;Chang, Hyo-Sik;Kim, Hyeong-Jun
    • New & Renewable Energy
    • /
    • 제8권1호
    • /
    • pp.18-23
    • /
    • 2012
  • The screen printing has been widely used to form silver electrodes in solar cell device due to their simplicity of process. However, the wavy and irregular surface which is believed to be originated from a screen mask mesh and thixotropic characteristics of paste on screen printing process is well-known to give a negative effect on solar cell efficiency. The dispensing method that the silver paste is extruded through micro nozzle under a moderate pressure and coated on substrate can form the silver electrode without any wavy surface. In this study, we optimize the composition of silver paste and develop paste blending condition based on the thixotropic behavior of paste. The optimized paste shows a large thixotropic loop area which is related to an aspect ratio of electrode line and has the viscosity of 40 $Pa{\cdot}s$ at 40 s-1. The electrode line we finally obtainis 67.2 ${\mu}m$ in width and has an aspect ratio of 0.277.

NTP-ERSN verification with C5G7 1D extension benchmark and GUI development

  • Lahdour, M.;El Bardouni, T.;El Hajjaji, O.;Chakir, E.;Mohammed, M.;Al Zain, Jamal;Ziani, H.
    • Nuclear Engineering and Technology
    • /
    • 제53권4호
    • /
    • pp.1079-1087
    • /
    • 2021
  • NTP-ERSN is a package developed for solving the multigroup form of the discrete ordinates, characteristics and collision probability of the Boltzmann transport equation in one-dimensional cartesian geometry, by combining pin cells. In this work, C5G7 MOX benchmark is used to verify the accuracy and efficiency of NTP-ERSN package, by treating reactor core problems without spatial homogenization. This benchmark requires solutions in the form of normalized pin powers as well as the vectors and the eigenvalue. All NTP-ERSN simulations are carried out with appropriate spatial and angular approximations. A good agreement between NTP-ERSN results with those obtained with OpenMC calculation code for seven energy groups. In addition, our studies about angular and mesh refinements are carried out to produce better quality solution. Moreover, NTP-ERSN GUI has also been updated and adapted to python 3 programming language.

The Effects of Ba-Ferrite Magnetic Abrasive Behavior on Polishing Characteristics (Ba-Ferrite계 자기연마재 거동이 연마특성에 미치는 영향)

  • Yun, Yeo-Kwon;Kim, Hee-Nam
    • Journal of the Korea Safety Management & Science
    • /
    • 제11권4호
    • /
    • pp.311-317
    • /
    • 2009
  • In this paper deals with behavior of the magnetic abrasive using Ba-Ferrite on polishing characteristics in a new internal finishing of STS304 pipe applying magnetic abrasive polishing. The magnetic abrasive using Ba-Ferrite grain WA used to resin bond fabricated low temperature. And Ba-Ferrite of magnetic abrasive powder fabricated that Ba-Ferrite was crused into 200 mesh. The previous research have made an experiment in the static state the movement of magnetic abrasive grain is nevertheless in the dynamic state. In this paper, We could have investigated into the changes of the movement of magnetic abrasive grain. In reference to this result, we could have made the experiment which is set under the condition of the magnetic flux density, polishing velocity according to the form of magnetic brush.

Absorptive Characteristics of a Helmholtz Resonator Damped by a Flexible Porous Screen (유연한 다공성 스크린을 가진 헬름홀쯔 공명기의 흡음특성)

  • Kim, Sang-Ryul;Kim, Yang-Hann
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 한국소음진동공학회 2005년도 춘계학술대회논문집
    • /
    • pp.865-868
    • /
    • 2005
  • A Helmholtz resonator is one of noise control elements widely used in many practical applications. The resonator has very high absorption at resonance frequency but the frequency bandwidth is very small. Therefore many kinds of additional resistive screens have been applied to the resonator's neck in order to increase the bandwidth. This paper discusses the absorptive characteristics of a Helmholtz resonator damped by a flexible porous screen in form of wire mesh. First, various experimental results are introduced and studied. Secondly, the effect of the resistive screen is theoretically predicted. It is shown that the distance between the screen and aperture affects on the resonance frequency as well as the absorption of the system.

  • PDF

Development of Machining Simulation System using Enhanced Z Map Model (Enhanced Z map을 이용한 절삭 공정 시뮬레이션 시스템의 개발)

  • 이상규;고성림
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 한국정밀공학회 2002년도 춘계학술대회 논문집
    • /
    • pp.551-554
    • /
    • 2002
  • The paper discusses new approach for machining operation simulation using enhanced Z map algorithm. To extract the required geometric information from NC code, suggested algorithm uses supersampling method to enhance the efficiency of a simulation process. By executing redundant Boolean operations in a grid cell and averaging down calculated data, presented algorithm can accurately represent material removal volume though tool swept volume is negligibly small. Supersampling method is the most common form of antialiasing and usually used with polygon mesh rendering in computer graphics. The key advantage of enhanced Z map model is that the data structure is same with conventional Z map model, though it can acquire higher accuracy and reliability with same or lower computation time. By simulating machining operation efficiently, this system can be used to improve the reliability and efficiency of NC machining process as well as the quality of the final product.

  • PDF

Development of the cutting simulation system with decomposition Algorithm. (분해 모델링 기법을 이용한 절삭 시뮬레이션 시스템 개발)

  • 김용현;고성림
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 한국정밀공학회 2004년도 추계학술대회 논문집
    • /
    • pp.422-425
    • /
    • 2004
  • This paper develops an octree-based algorithm for machining simulation. Most commercial machining simulators are based on the Z map model, which has several limitations in terms of achieving a high level of precision in five-axis machining simulation. Octree representation being a three-dimensional (3D) decomposition method, an octree-based algorithm is expected to be able to overcome such limitations. With the octree model, storage requirement is reduced. Moreover, recursive subdivision is processed in the boundaries, which reduces useless computations. The supersampling method is the most common form of antialiasing and is typically used with polygon mesh rendering in computer graphics. The supersampling technique is being used to advance the efficiency of the octree algorithm..

  • PDF

An Improved Method for Mesh Grounding System Using Unequally Spaced Arrangement (접지도체의 간격배치에 따른 개선된 접지설비 모델)

  • Choi, Hong-Kyoo;Song, Young-Joo
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
    • /
    • 한국조명전기설비학회 2004년도 학술대회 논문집
    • /
    • pp.259-265
    • /
    • 2004
  • No matter how well the equally spaced grounding grid is designed, there are questions keep rising, such as leakage of current from comer conductor, high voltage of touch voltage in corners of grid than in center, and high material cost for grounding grid. The best-fitted design for unequally spaced grounding grid is a part that must be considered. Explain advantages of unequally spaced grounding grid and lead formula by dividing the number of grid division, j, into 20, instead of 7. Then present $D_{ij}$, which is optimum rate for unequally spaced grounding grid and verify safety and economy of the unequally spaced grounding grid by computer simulation with a poly-nominal function form.

  • PDF

Development of a Pre-Processing Program for Flow Analysis Based on the Object-Oriented Programming Concept (OOP 개념에 기초한 유동해석용 전처리 프로그램 개발)

  • Myong, Hyon-Kook;Ahn, Jong-Ki
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • 제32권1호
    • /
    • pp.70-77
    • /
    • 2008
  • A pre-processing program based on the OOP(object-oriented programming) concept has been developed. The program consists of the input of a 2D or 3D flow problem to a CFD program by means of an user-friendly interface and the subsequent transformation of this input into a form suitable for the solver(PowerCFD) using unstructured cell-centered method. User-friendly GUI(graphic user interface) has been built on the base of MFC(Microsoft Foundation Class). The program is organized as modules by classes based on VTK(Visualization ToolKit)-library, and these classes are made to function through inheritance and cooperation which is an important and valuable concept of object-oriented programming. The major functions of this program are introduced and demonstrated, which include mesh generation, boundary settings, solver settings, generation of grid connectivity and geometric data etc.

A Study on Error Verification of STL Format for Rapid Prototyping System (급속조형 시스템을 위한 STL 포맷의 오류 검증에 관한 연구)

  • Park, H.T.;Lee, S.H.
    • Journal of the Korean Society for Precision Engineering
    • /
    • 제13권10호
    • /
    • pp.46-55
    • /
    • 1996
  • As industrial standard data, the STL format which approximates three dimensional CAD model to triangular facets, is used for RP(Rapid Prototyping) system in recent days. Because most RP system take the only form of two dimensional line segments as an input stream inspite of its imperfectness while converting into STL format, a CAD model is converted into a standard industrial format which is composed of many triangular facets. The error verifying process is composed of four main steps, and these are 1) Remove facets with two or more vertices equal to each other. 2) Fix overlapping error such as more than three facets adjacent to anedge. 3) Fill holes in the mesh by using Delaunay triangulation method. 4) Correct the wrong direction and normal vectors. This paper is concerned with serching the mentioned errors in advance and modifying them.

  • PDF