• 제목/요약/키워드: Surface of revolution

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CONSTANT CURVATURES AND SURFACES OF REVOLUTION IN L3

  • Kang, Ju-Yeon;Kim, Seon-Bu
    • 호남수학학술지
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    • 제38권1호
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    • pp.151-167
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    • 2016
  • In Minkowskian 3-spacetime $L^3$ we find timelike or spacelike surface of revolution for the given Gauss curvature K = -1, 0, 1 and mean curvature H = 0. In fact, we set up the surface of revolution with the time axis for z-axis to be able to draw those surfaces on standard pictures in Minkowskian 3-spacetime $L^3$.

회전체의 Isophote 구성요소의 효율적인 계산 (Efficient Computation for Connected Components of an Isophote in a Surface of Revolution)

  • 김구진;이인권
    • 한국정보과학회논문지:시스템및이론
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    • 제29권8호
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    • pp.440-444
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    • 2002
  • 본 논문에서는 회전체(surface of revolution)의 isophote를 계산하는 효율적이고 안정성 있는 알고리즘을 제시한다. 회전체는 곡면의 특성 상 곡면이 원의 집합으로 이루어지며 하나의 원 위에 있는 점들에 대한 법선 벡터의 집합은 하나의 원뿔(cone)을 이룬다. 원뿔을 이루는 법선 벡터의 특성과 회전체의 대칭성을 이용하여 곡선과 직선의 교점 계산만으로 isophote에 속한 모든 구성요소(connected component)를 발견하는 방법을 제시한다. 또한 회전체 곡면 상의 isophote를 매개변수 곡선으로 표현함으로써 곡선을 쉽게 추적하는 방법을 제시한다.

BOUR'S THEOREM IN 4-DIMENSIONAL EUCLIDEAN SPACE

  • Hieu, Doan The;Thang, Nguyen Ngoc
    • 대한수학회보
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    • 제54권6호
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    • pp.2081-2089
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    • 2017
  • In this paper we generalize 3-dimensional Bour's Theorem to the case of 4-dimension. We proved that a helicoidal surface in $\mathbb{R}^4$ is isometric to a family of surfaces of revolution in $\mathbb{R}^4$ in such a way that helices on the helicoidal surface correspond to parallel circles on the surfaces of revolution. Moreover, if the surfaces are required further to have the same Gauss map, then they are hyperplanar and minimal. Parametrizations for such minimal surfaces are given explicitly.

SURFACES OF REVOLUTION WITH MORE THAN ONE AXIS

  • Kim, Dong-Soo;Kim, Young-Ho
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제19권1호
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    • pp.1-5
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    • 2012
  • We study surfaces of revolution in the three dimensional Euclidean space $\mathbb{R}^3$ with two distinct axes of revolution. As a result, we prove that if a connected surface in the three dimensional Euclidean space $\mathbb{R}^3$ admits two distinct axes of revolution, then it is either a sphere or a plane.

4차 산업혁명에 따른 시장요구 변화와 한국 표면처리 산업의 발전방향에 대한 연구 (The Influence of the Fourth Industrial Revolution in Market Demands and the Directions for Developing Korean Surface Finishing Industries)

  • 이승재;허진영;이홍기
    • 한국표면공학회지
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    • 제51권1호
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    • pp.71-78
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    • 2018
  • This paper examines various definitions of the fourth industrial revolution and its influence on typical market demands and manufacturing methods. And this study reviewed the policies of the major global competitors in preparedness for the fourth industrial revolution. In conclusion, this paper suggested various possible developing ways in which Korean companies, especially focused on surface treatment firms, could adapt and survive in such a revolutionary industrial circumstance change.

SURFACES OF REVOLUTION WITH POINTWISE 1-TYPE GAUSS MAP IN PSEUDO-GALILEAN SPACE

  • Choi, Miekyung;Yoon, Dae Won
    • 대한수학회보
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    • 제53권2호
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    • pp.519-530
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    • 2016
  • In this paper, we study surfaces of revolution in the three dimensional pseudo-Galilean space. We classify surfaces of revolution generated by a non-isotropic curve in terms of the Gauss map and the Laplacian of the surface. Furthermore, we give the classification of surfaces of revolution generated by an isotropic curve satisfying pointwise 1-type Gauss map equation.

엔드밀 가공시 진동, 표면거칠기, 절삭온도에 미치는 최적가공조건에 관한 연구 (The Study on the Optimal Working Condition for Vibration, Surface Roughness and Cutting Temperature in End-milling)

  • 홍도관;김동영;안찬우
    • 한국소음진동공학회논문집
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    • 제14권12호
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    • pp.1322-1329
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    • 2004
  • End-milling has been used widely in industrial system because it is effective to a material manufacturing with various shapes. Recently the end-milling processing is needed the high-precise technique with good surface roughness and rapid time in precision machine part and electronic part. The optimum mechanical vibration of main spindle, surface roughness and cutting temperature have an effect on end-milling condition such as, cutting direction, revolution of spindle, feed rate and depth of cut, etc. Therefore, this study carried to decide the working condition for optimum mechanical vibration of main spindle, surface roughness and cutting temperature using design of experiments, ANOVA and characteristic function. From the results of experimentation, mechanical vibration has an effect on revolution of spindle, radial depth of cut, and axial depth of cut. The surface roughness has an effect on cutting direction, revolution of spindle and depth of cut. And then the optimum condition used design of experiments is upward cutting In cutting direction, 600 rpm in revolution of spindle, 240 mm/min in feed rate, 2 mm in axial depth of cut and 0.25 mm in radial depth of cut. By design of experiments and characteristic function, it is effectively represented shape characteristics of mechanical vibration, surface roughness and cutting temperature in end-milling.

고속회전을 이용한 마이크로 엔드밀의 가공특성 (Machining characteristics of micro end-mill using high revolution)

  • 김기수;김상진;조병무;김형철
    • 대한공업교육학회지
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    • 제31권2호
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    • pp.350-363
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    • 2006
  • 최근 마이크로 엔드밀을 이용한 가공은 소형구조물이나 소형기계의 부품과 금형산업에서 양호한 표면 거칠기와 가공시간의 단축을 위해 고정도의 기술을 요구하고 있다. 마이크로 엔드밀을 이용한 가공에 있어서 가공조건은 절삭면의 표면거칠기에 커다란 영향을 미치게 된다. 따라서 본 연구에서는 마이크로 엔드밀을 이용하여 스테인리스 강(STS 304)의 표면을 가공하였고, 실험계획법에 의해 최적의 표면거칠기를 얻기 위한 가공조건에 대해 분산분석하였다. 본 연구를 통하여 마이크로 엔드밀에 의한 가공에서 가공조건은 절삭깊이, 스핀들의 회전수, 이송속도의 순서로 표면거칠기에 영향을 미치는 것을 알았다.

72.5 Ah NCM계 파우치형 리튬이온배터리의 표면온도 상승률이 열폭주 발생시간에 미치는 영향 분석 (Analysis of Effect of Surface Temperature Rise Rate of 72.5 Ah NCM Pouch-type Lithium-ion Battery on Thermal Runaway Trigger Time)

  • 이흥수;홍성호;이준혁;박문우
    • 한국안전학회지
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    • 제36권5호
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    • pp.1-9
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    • 2021
  • With the convergence of the information and communication technologies, a new age of technological civilization has arrived. This is the age of intelligent revolution, known as the 4th industrial revolution. The 4th industrial revolution is based on technological innovations, such as robots, big data analysis, artificial intelligence, and unmanned transportation facilities. This revolution would interconnect all the people, things, and economy, and hence will lead to the expansion of the industry. A high-density, high-capacity energy technology is required to maintain this interconnection. As a next-generation energy source, lithium-ion batteries are in the spotlight today. However, lithium-ion batteries can cause thermal runaway and fire because of electrical, thermal, and mechanical abuse. In this study, thermal runaway was induced in 72.5 Ah NCM pouch-type lithium-ion batteries because of thermal abuse. The surface of the pouch-type lithium-ion batteries was heated by the hot plate heating method, and the effect of the rate of increase in the surface temperature on the thermal runaway trigger time was analyzed using Minitab 19, a statistical analysis program. The correlation analysis results confirmed that there existed a strong negative relationship between each variable, while the regression analysis demonstrated that the thermal runaway trigger time of lithium-ion batteries can be predicted from the rate of increase in their surface temperature.

금형강의 고속가공시 절삭력 및 표면조도의 특성 (Characteristics of Cutting Force and Surface Roughness in the High-Speed Machining of Die Material)

  • 손창수;강명창;이용철;이득우;김정석
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1996년도 추계학술대회 논문집
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    • pp.36-40
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    • 1996
  • The high-speed machining is one of the most effective technology to improve productivity. Because of the high speed and high feedrate, high-speed machining can give great advantages for the machining of dies and moulds. In this paper, high-speed milling for HP-4 die material was carried out with coated tungsten carbide ball endmill. In the high-speed machining, the cutting force and surface roughness of workpiece show very various characteristics at different cutting conditions. Especially surface roughness of workpiece depends largely on pick feed and feed per revolution of ball endmill. In the condition that pick feed and feed per revolution are equal, better surface roughness is measured. By obtaining good surface roughness at high speed, efficiency of machining can be increased.

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