• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.137-141
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• 2003

CRTs can survive in the long run for TV applications, because of their realistic reproduction of live images. CRT technology development has to be directed towards form factor, but also attention has to be paid to the form design of sets. The CRT is the only technology allowing a doubly curved screen surface.

• 한국광학회:학술대회논문집
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• 한국광학회 2007년도 동계학술발표회 논문집
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• pp.207-208
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• 2007

• Journal of Information Display
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• 제4권1호
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• pp.38-42
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• 2003

CRTs can survive in the long run for TV applications, because of their realistic reproduction of live images. CRT technology development has to be directed towards form factor, but also attention has to be paid to the form design of sets. The CRT is the only technology allowing a doubly curved screen surface.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1221-1222
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• 2011

• 대한기계학회논문집
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• 제6권3호
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• pp.222-231
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• 1982

A single free jet formed by the interaction of two curved wall jets on a Cylinder surface is defined as "the Coanda nozzle jet" in this study. In order to investigate the characteristics of Coanda nozzle jet, an experimental analysis was carried out; measurements of the static pressure distribution on the cylinder surface, the mean velocity profile, the turbulence intensity, and the Reynolds shear stress by using x-type hot-wire probe.ire probe.

• Journal of Ginseng Research
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• 제36권3호
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• pp.314-321
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• 2012

The purpose of this study was to determine a standard quality characteristic through the evaluation and statistical analysis of the morphological characteristics of dried ginseng (white ginseng) products. Samples of 4-year-old 30 and 50 piece grade curved ginseng and 5-year-old 25 and 15 piece grade straight ginseng products were collected from a market, with 5 to 10 packs of each product being collected annually over a 5-year period (2006-2010). Morphological characteristics, such as weight, length, diameter, and surface color, were measured and statistically analyzed to present a standard quality characteristic value using $mean{\pm}3SD$, a range that excluded outlier. The 4-year-old curved ginseng samples of 50 and 30 piece grade were 4.80 to 6.12 cm and 5.28 to 7.60 cm long, 0.22 to 1.70 cm and 0.21 to 2.07 cm wide, and weighed 5.28 to 7.40 g and 8.62 to 12.26 g, respectively. The 5-year-old straight ginseng samples of 25 and 15 piece grade were 9.66 to 15.47 cm and 10.66 to 16.80 cm long, 1.32 to 1.94 cm and 1.48 to 2.43 cm wide, and weighed 9.18 to 16.40 g and 15.89 to 24.82 g, respectively. The surface color of the different piece grades in the same type of dried ginseng product was similar, whereas the straight ginseng demonstrated a lower level of brightness, but the relative redness and yellowness were of higher levels, than that of curved ginseng.

• 대한기계학회논문집A
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• 제35권9호
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• pp.1071-1076
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• 2011

본 연구에서는 산업용 다관절 로봇을 이용한 3 차원 곡면가공 방안에 대하여 연구하였다. 가반중량이 큰 산업용 로봇의 경우 반복위치정밀도가 높지 않아 위치오차와 가공 깊이 방향 오차를 발생시키며, 본 연구에서는 레이저 변위센서를 이용하여 이를 보정하는 방법을 제시하였다. 로봇교시포인터의 수를 줄이기 위하여 가공면의 특이점들만을 이용하여 곡면 가공이 가능하도록 로봇 궤적을 생성하는 방안을 연구하였다. 본 연구에서는 실제 산업용 로봇을 이용하여 가공시험을 수행하였다. 회전수, 가공각도, 가공깊이, 가공속도 등의 가공조건을 변경해가며, 표면조도, 실제 가공깊이, 진동 및 소음 발생에 대한 시험을 수행하여 적용 가능한 가공조건을 도출하였다.

• Geomechanics and Engineering
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• 제36권2호
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• pp.131-143
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• 2024

Shield tunneling construction commonly crosses underground pipelines in urban areas, resulting in soil loss and followed deformation of grounds and pipelines nearby, which may threaten the safe operation of shield tunneling. This paper investigated the pipeline deformation caused by double curved shield tunnels in soil-rock composite stratum in Nanjing, China. The stratum settlement equation was modified to consider the double shield tunneling. Moreover, a three dimensional finite element model was established to explore the effects of hard-layer ratio, tunnel curvature radius, pipeline buried depth and other influencing factors. The results indicate the subsequent shield tunnel would cause secondary disturbance to the soil around the preceding tunnel, resulting in increased pipeline and ground surface settlement above the preceding tunnel. The settlement and stress of the pipeline increased gradually as buried depth of the pipeline increased or the hard-layer ratio (the ratio of hard-rock layer thickness to shield tunnel diameter within the range of the tunnel face) decreased. The modified settlement calculation equation was consistent with the measured data, which can be applied to the settlement calculation of ground surface and pipeline settlement. The modified coefficients a and b ranged from 0.45 to 0.95 and 0.90 to 1.25, respectively. Moreover, the hard-layer ratio had the most significant influence on the pipeline settlement, but the tunnel curvature radius and the included angle between pipeline and tunnel axis played a dominant role in the scope of the pipeline settlement deformation.

• 소성∙가공
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• 제21권7호
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• pp.432-440
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• 2012

In this article, the design of the flexible forming process considering die shape compensation using an iterative over-bending method based on numerical simulation was conducted. In this method, the springback shape obtained from the final step of the first forming simulation is compared with the desired objective shape, and a shape error is calculated as a vector norm with three-dimensional coordinates. The error vector is inversely added to the objective surface to compensate both the upper and lower flexible die configurations. The flexible die shapes are recalculated and the punch arrays are adjusted according to the over-bent forming surface. These iterative procedures are repeated until the shape error variation converges to a small value. In addition, experimental verification was conducted using a 2000-kN flexible forming apparatus for thick plates. Finally, the configuration of the prototype obtained from the experiment was compared with the numerical simulation results, which had springback compensation. It is confirmed that the proposed method for compensating for the forming error could be used in the design of flexible forming of thick-curved plates.

• 소성∙가공
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• 제18권7호
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• pp.556-564
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• 2009

Flexible forming process for sheet material using reconfigurable die is introduced based on numerical simulation. In general, this flexible forming process using the reconfigurable die has been utilized for manufacturing of curved thick plates used for hull structures, architectural structures and so on. In this study, numerical simulation of sheet metal forming process is carried out by using flexible dies model instead of conventional matched die set. The numerical simulation and experimental verification for sheet metal forming process using a flexible forming machine that is more suitable for thick plate forming process are carried out to confirm the appropriateness of the simulation process. As an elastic cushion, urethane pads are utilized using hyperelastic material model in the simulation for smoothing the forming surface which is discrete due to characteristics of the flexile die. In the flexible forming process for sheet metal, effect of a blank holder is also investigated according to blank holding methods. Formability in view of occurrence of dimples is compared with regard to the various punch sizes. Consequently, it is confirmed that the flexible forming for sheet material using urethane pad has enough capability and feasibility for manufacturing of smoothly curved surface instead of conventional die forming method.