• 에너지공학
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• 제23권2호
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• pp.21-27
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• 2014

수직평판의 거칠기에 따른 자연대류 열전달의 변화를 실험적으로 측정하였다. 열전달 실험을 대신하여 유사성에 기초한 물질전달로 모사하여 실험을 수행하였다. 또한 국부적인 열전달률을 알기위해 Piecewise electrode를 채택하였다. Pr수는 2,014 그리고 높이(L)는 0.154m로 고정하고 매끈한 수직평판에 대해 실험을 수행한 결과 Le Fevre의 수직평판 상관식과 거의 일치하였다. 거칠기 정도를 $0.5R_z{\mu}m{\sim}14.1R_z{\mu}m$로 변화시켰을 때 $Nu_L$수는 거칠기 정도가 커지면서 증가하는 경향을 나타내었다. 실험결과는 간단한 상관식으로 정리하였다.

• 한국산업정보학회논문지
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• 제24권2호
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• pp.47-55
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• 2019

본 논문에서는 조명의 영향을 받지 않는 깊이 정보를 이용한 번호판 검출 방법을 제안한다. 깊이 정보를 통해 블록 내 화소들의 3차원 카메라 좌표를 구하고, 이를 통해 블록 내 평면의 인자를 계산한다. 그 후 인접한 블록간의 평면의 법선 벡터들을 비교하여 유사도를 측정한다. 평면 유사도가 높을 경우 두 블록이 한 평면에 속해 있다고 간주하여 그룹화함으로써 평면 영역을 검출한다. 검출된 평면 영역에 대해 깊이 정보를 이용하여 영역의 높이와 너비를 실제 번호판과 비교하여 번호판을 검출한다.

• 국제강구조저널
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• 제18권4호
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• pp.1210-1218
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• 2018

A new type of earthquake-resisting element that consists of a steel plate shear wall with slits is introduced. The infill steel plate is divided into a series of vertical flexural links with vertical links. The steel plate shear walls absorb energy by means of in-plane bending deformation of the flexural links and the energy dissipation capacity of the plastic hinges formed at both ends of the flexural links when under lateral loads. In this paper, finite element analysis and experimental studies at low cyclic loadings were conducted on specimens with steel plate shear walls with multilayer slits. The effects caused by varied slit pattern in terms of slit design parameters on lateral stiffness, ultimate bearing capacity and hysteretic behavior of the shear walls were analyzed. Results showed that the failure mode of steel plate shear walls with a single-layer slit was more likely to be out-of-plane buckling of the flexural links. As a result, the lateral stiffness and the ultimate bearing capacity were relatively lower when the precondition of the total height of the vertical slits remained the same. Differently, the failure mode of steel plate shear walls with multilayer slits was prone to global buckling of the infill steel plates; more obvious tensile fields provided evidence to the fact of higher lateral stiffness and excellent ultimate bearing capacity. It was also concluded that multilayer specimens exhibited better energy dissipation capacity compared with single-layer plate shear walls.

• 대한기계학회논문집B
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• 제22권6호
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• pp.750-756
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• 1998

In this study, condensation tests were conducted on a vertically finned plate (fin height 1 mm, fin thickness 1 mm, fin spacing 1 mm) using R-113. Results showed that fins enhanced the condensation on a vertical plain surface as much as four times. Comparison with theoretical models revealed that the effect off surface tension should be included in the model. The effect of interruption plates was also investigated. The plates were not effective in enhancing the finned plate condensation. The reason may be attributed to the already thinned condensate film on the finned surface.

• 한국분무공학회지
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• 제1권2호
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• pp.66-73
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• 1996

The present study investigates experimentally the characteristics of liquid jet, which is, the spray flow in the normal direction of the air stream under the flow conditions of air velocity $110\sim125m/s$. The present study adopts with the flow visualization technique using a short duration light bulb and the image processing analyse with CCD camera. Two types of injector were used: one is a flat plate type, and the other is backward facing step type, which height are 5, 8, 10mm. Dispersion of liquid jet can be represented by gray level of CCD camera. In the upstream of liquid jet, the backward facing step shows better liquid jet penetration. However, in the downstream. mean droplet size for backward facing step injector is smaller than that for flat plate injector

• 한국전자파학회논문지
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• 제15권11호
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• pp.1116-1122
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• 2004

플랜지된 평행 평판 도파관의 슬릿을 통한 전자기적인 결합문제를 고려하였다. 결합 슬릿 근처 도파관 내 $.$외부의 무효전력을 반영한 슬릿의 등가 어드미턴스를 구하고, 슬릿의 폭이 매우 좁은 경우에서의 최대결합 메커니즘을 규명하였다. 도파관의 높이, 슬릿의 폭 및 슬릿의 변위 등과 같은 구조적인 파라미터들이 복사 특성에 미치는 영향을 관찰하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1219-1224
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• 2004

The objective of this study is to propose an experimental calibration facility in which a heat flux sensor can be calibrated under conductive condition by using helium gas. The heat flux calibration facility was designed, simulated and manufactured for use in a high heat transfer condition. It delivers heat fluxes up to a maximum of 35 KW $m^{-2}$. A copper block heated electrically with 3.5 KW power is designed to produce uniform temperature up to 600 K across its face. High heat fluxes are provided between hot plate and cold plate by 1 mm height helium filled gap. A cold plate is maintained around 300 K through pool boiling using a refrigerant and water-cooled heat exchanger. A simulation was conducted to verify the design of the main test section. To verify the performance of calibration facility, a heat flux sensor was examined. The measured heat fluxes were compared to the calculated one.

• 전기학회논문지P
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• 제61권2호
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• pp.93-96
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• 2012

We have designed high performance prism light-guide plate (LGP) in 17 inch TFT-LCD. In test result to embody high brightness BLU in case of LGP of base and upper surface with 17 inch, thickness 8mm adding prism construct. Using optical simulation, we forecast the brightness and uniformity in LGP with prism structure. And we adopted novel injection mold method and Nickel stamper to make actual evolution sample. Novel injection mold process has steady heating time zone in heat cycle time of injection mold process. For this novel heat cycle control, we achieved above 90[%] height prism structure as our design. It is superior brightness improvement than previous that of printing form about some 20[%] and in this course to embody actual material it succeeded prism LGP production by 17 inch injection form process.

• Asian Journal of Atmospheric Environment
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• 제5권3호
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• pp.196-203
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• 2011

The main aim of this study is to establish methods of morphological preservation and elemental quantification for individual snow crystals. Individual snow crystals were collected at a height of 20 m above ground level. To stabilize and preserve the original morphologies of the snow crystals, cyanoacrylate, which has been used to fix liquid droplets, was applied (Kasahara et al., 2000). Several different kinds of snow crystals (dendrite, sectored plate, quasi-sectored plate, and hexagonal plate) were successively stabilized using this method. The stabilized snow crystals were pretreated with acetone, and then the elemental components contained in a whole snow crystal were quantified with the Particle Induced X-ray Emission (PIXE) analytical technique. The snow crystal residual composition determined in the present study was dominated by sulfur and mineral components, and the elemental mass showed an apparent crystal size dependence, where the elemental mass gradually decreased as the crystal size increased.

• 설비공학논문집
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• 제14권3호
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• pp.199-205
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• 2002

In this paper, the optimum shape and arrangement of ribs in the channel of a plate heat exchanger are studied. The following dimensionless geometric parameters of ribs are selected as design variables: rib height ($H_R$), angle of attack ($\beta$), rib pitch ($P_R$), rib distance (L) and aspect ratio of rib (AR). The optimization is performed by minimizing the objective function consisting of the Nusselt number and the friction factor. The optimal values of design variables are as follows: $H_R$=0.263, $\beta$=0.290, $P_R$=3.142, L: 3.954, AR=0.342. The pressure drop and the heat transfer of the optimum model, compared to those of the reference model, are increased by 15.1% and 41.6%, respectively.