• 한국CDE학회논문집
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• 제2권4호
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• pp.253-266
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• 1997

Pencil-curve machining, which is a single-pass ball-end milling along a concave edge on adie surface, is widely employed in die-surface machining. The cutter-path used for pencil-curve machining, which is the trajectory of the “ball-center point” of a ball-endmill sliding along a concave-edge region on the die surface, is called pencil-curve. Presented in the paper is a pencil-curve tracing algorithm in which “concave-type” sharp edges are computed from a “virtually digitized” model of the tool-envelope surface. The resulting “initial” pencil-cures are then refuted by applying a series of fairing operations. illustrative examples and methods for enhancing accuracy are also presented. The proposed pencil-curve tracing algorithm has been successfully implemented in a commercial CAM system specialized in die-machining and in the CAD/CAM system CATIA.

• Journal of Mechanical Science and Technology
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• 제18권6호
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• pp.1042-1051
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• 2004

The vortex flow characteristics of a sharp-edged delta wing at high angles of attack were studied using a computational technique. Three dimensional, compressible Reynolds-averaged Navier-Stokes equations were solved to understand the effects of the angle of yaw, angle of attack, and free stream velocity on the development and interaction of vortices and the relationship between suction pressure distributions and vortex flow characteristics. The present computations gave qualitatively reasonable predictions of vortical flows over a delta wing, compared with past wind tunnel measurements. With an increase in the angle of yaw, the symmetry of the pair of leading edge vortices was broken and the vortex strength was decreased on both windward and leeward sides. An increase in the free stream velocity resulted in stronger leading edge vortices with an outboard movement.

• 한국정밀공학회지
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• 제19권3호
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• pp.80-87
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• 2002

Tungsten carbide microshaft is used as micro-punch, electrode of MEDM (micro-electro-discharge machining), and micro-tool because it has high hardness and high rigidity. In this study, the tungsten carbide microshaft was fabricated using electrochemical machining. Concentration of material removal at the sharp edge and metal corrosion layer affect the shape of the microshaft. Control of microshaft shape was possib1e through conditioning the machining voltage and electrolyte concentration. By applying periodic voltage, material removal rate increased and surface roughness improved. The fabricated microshaft in $H_2 SO_4$ electrolyte maintained sharper end edge and better surface finish than those fabricated by other electrolytes.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.868-870
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• 2009

Here we report another soft lithography, peel-off method, for patterning conductive polymer anodes in the fabrication of flexible ITO-free organic light-emitting diodes. This method doesn't require any heating process and UV light. We have demonstrated that such a peel-off technique enables the formation of a very sharp edge and the enhancement of edge roughness.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.513-516
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• 1987

Hydrogenated amorphous silicon (a-Si:H) films have been deposited, for thye first time, by a remote plasma chemical vapor deposition. The hydrogen radical play a important role to control the deposition rate, The bonded hydrogen content to silicon is independent of hydrogen partial pressure in the plasma. Optical gap of deposited a-Si:H lies between 1.7eV and 1.8eV and all samples have sharp absorption edge. B-doped a-Si:H films by a RPECVD has a high doping efficiency compared with plasma CVD. The Fermi level of 100ppm B-doped film lies at 0.5eV above valence band edge.

• 융합보안논문지
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• 제8권4호
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• pp.127-134
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• 2008

본 연구는 투명 성질을 가진 물방울의 윤곽선에 대한 효율적인 검출을 통해 분석 장비의 자동 측정에 대한 정확성을 향상시키는 것을 목적으로 한다. 투명성질을 가지는 원의 윤곽선 검출을 위해 밝기 분포에 대한 국소적 미분 대신에 적응성 방향 미분(Adaptive Directional Derivative；ADD)이라는 비국소적 연산자를 도입함으로써 에지의 램프 폭의 변화에 무관하게 에지 검출에 적용할 수 있는 MADD(Modified Adaptive Directional Derivative) 알고리즘을 사용한다. 이 방법은 램프 구간 내에서 방향 미분 값을 가중치로 사용하여 픽셀들의 위치를 평균한 방향 미분의 국소 중심(Local Center of Directional Derivative；LCDD)등의 위치를 찾는 추가적인 과정없이, 정확한 에지 픽셀의 위치가 완전 선명화 사상에 의한 단순 계단 함수의 위치로 자연스럽게 결정될 수 있다. 제시된 에지 검출 방법을 표면분석 기술인 접촉각 연산에 적용하여 실험 및 결과 분석을 통해 제안 기법의 타당성 및 효율성을 검증한다.

• Tribology and Lubricants
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• 제38권3호
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• pp.73-83
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• 2022

This paper is concerned with an analysis of a surface edge crack emanated from a sharp contact edge. For a geometrical model, a square wedge is in contact with a half plane whose materials are identical, and a surface perpendicular crack initiated from the contact edge exists in the half plane. To analyze this crack problem, it is necessary to evaluate the stress field on the crack line which are induced by the contact tractions and pseudo-dislocations that simulate the crack, using the Bueckner principle. In this Part I, the stress filed in the half plane due to the contact is re-summarized using an asymptotic analysis method, which has been published before by the author. Further focus is given to the stress field in the half plane due to a pseudo-edge dislocation, which will provide a stress solution due to a crack (i.e. a continuous distribution of edge dislocations) later, using the Burgers vector. Essential result of the present work is the corrective functions which modify the stress field of an infinite domain to apply for the present one which has free surfaces, and thus the infiniteness is no longer preserved. Numerical methods and coordinate normalization are used, which was developed for an edge crack problem, using the Gauss-Jacobi integration formula. The convergence of the corrective functions are investigated here. Features of the corrective functions and their application to a crack problem will be given in Part II.

• Journal of Photoscience
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• 제9권2호
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• pp.460-462
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• 2002

Absorption spectra of biological specimens in the soft X-ray region have been presented with special reference to the XANES (X-ray absorption Near Edge Structure) of constituent elements. Absorption spectrum in this wavelength region is characterized by the absorption edges from which elemental content could be derived. In addition, XANES has a characteristic profile for chemical environment around the element such as chemical bond. Using the specific absorption peak we can assign not only the chemical bond but also molecules having such a chemical bond. In the present paper, absorption spectrum of DNA was measured in the wavelength range from 1.5nm to 5nm. Spectrum of Chinese Hamster Ovary (CHO) cells was compared with the DNA spectrum. XANES were distinct at the K absorption edges of major elements, C, N and O. In the spectrum of the cells prominent peaks at the L absorption edge of minor element Ca were also detectable. XANES profiles in small local areas in a cell could also be measured in combination with X-ray microscopy. These give information about local chemical environment in a cell. XANES at the phosphorus K absorption edge in a human HeLa cell was successfully obtained corresponding to a sharp and intensive XANES peak of DNA.

• 한국전자통신학회논문지
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• 제9권3호
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• pp.369-376
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• 2014

최근 기후변화와 각 나라의 해양확보로 인하여 수산자원의 급감을 해결하기 위한 친환경 양식업이 부각되고 있다. 해양 양식업 작업의 편이성을 제공하기 위해 어업용 선박 크레인을 사용한다. 본 논문에서는 영상처리기를 이용하여 기본의 선박 크레인의 작업환경을 개선하고 영상장비를 통해 입력받은 작업영역의 영상정보를 모니터링 및 분석하여 영상을 최적화하고, 작업자에게 편리하고 높은 가시성을 갖도록 하는 실시간 영상 가이드 시스템을 제안한다.

• 한국레이저가공학회지
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• 제16권2호
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• pp.12-15
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• 2013

In this paper, we controlled the edge angle of fiber by using $CO_2$ laser. In order to control the angle, tilting angle of fiber on stage and the number of scan repetition are adjusted, and laser power is fixed at 30 W in the experiment. In the polishing result, the edge angle of fiber can be changed from $4^{\circ}$ to $8^{\circ}$, as changing the tilting angle and the number of scan repetition. This $CO_2$ laser polishing can fabricate ball lenses with various curvatures and a sharp probe as well as the edge angled fiber.