• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.14-20
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• 2001

On the bending process, metal-strap plays an important role in dispersing the stress generated in wood. Therefore, the metal-strap has more influence on the property of bentwood materials. The effect of the metal-strap thickness for bentwood was examined. The effect of metal-strap on the bending properties of Korean red pine(Pinus densiflora Sieb. et Zucc.)was investigated in this research. The metal-strap thickness is divided into 4 kinds such as 1.0, 0.8, 0.6, 0.4 mm. The specimens were selected by grain such as annual ring angles, flat grain and half-edge grain specimens. As a result of this study, the bending ability of 1.0, 0.8 mm, thickness of half-edge grain specimens was better than flat grain specimens but the result of 0.6, 0.4 mm were reversed. The bending ability of half-edge grain was better than flat grain and the grade was higher. When the processed specimens were dried, the radius of curvature(ROC) was decreased became drying-stress was not perfectly dispersed. An optimum drying-condition would deminish this phenomenon.

• Journal of the Korean Ceramic Society
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• v.42 no.9 s.280
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• pp.599-601
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• 2005

The coarsening process of two different $BaTiO_3$ single crystal seeds, one with a (111) double twin and the other without it, was investigated. Due to the presence of Twin Plane Reentrant Edge (TPRE), the coarsening rate of the twinned seed crystal was significantly higher than that without a twin. For the coarsening by the 2-dimensional nucleation and lateral growth, the energy barrier for nucleation at the TPRE was analyzed to be about a half compared with that at the terrace planes.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.83-83
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• 2011

본 연구에서는 p-type Si (100) 위에 분자선 에피택시 성장방법으로 ZnO 완충층이 삽입된 ZnO 박막을 성장시켰다. ZnO 완충층은 Zn 셀 셔터의 열림/닫힘을 반복하는 성장 멈춤법으로 성장되었다. Zn 셀 셔터의 열림 시간은 4분, 2분, 1분이며 닫힘 시간은 2분으로 동일하게 유지하였다. 이러한 과정은 각각 5, 10, 20회로 반복되었으며 ZnO 완충층을 성장한 후 ZnO 박막은 기존의 분자선 에피택시 방법으로 성장되었다. ZnO 박막의 구조적, 광학적 특성은 field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), photoluminescence (PL)로 조사하였다. SEM 측정결과 성장 멈춤 횟수가 증가함에 따라 ZnO 박막의 표면은 섬(island) 구조에서 미로(maze) 구조로 변화하였고, XRD 측정결과 full-width at half-maximum (FWHM) 이 감소하고 결정립 크기(grain size)가 증가하였다. 그리고 PL 측정결과 성장 멈춤 횟수가 증가함에 따라 near-band-edge emission (NBE) 피크의 세기가 증가하였고 deep-level emission (DLE) 피크의 위치는 오렌지 발광에서 녹색 발광으로 청색편이(blue-shift)하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.233-233
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• 2010

CdS thin films were deposited on glass substrates by R.F. magnetron sputtering method and some of the samples were treated by rapid thermal annealing (RTA) process. Effects of thermal annealing on structural and optical properties were investigated at different temperatures ranging from 100 to $600^{\circ}C$. The crystallographic structure of the films and the size of the crystallites in the films were studied by X-ray diffraction. The crystallite sizes were found to increase, and the X-ray diffraction patterns were seen to sharpen by annealing. Optical properties of the films were calculated using the envelope method and the photoluminescence measurements. The optical properties of the films were seen to be dependent on the film thicknesses. The energy gap of the films was found to decrease by annealing. The band edge sharpness of the optical absorption was seen to oscillate by thermal annealing. Annealing over $400^{\circ}C$ was seen to degrade the optical properties of the film. The best annealing temperature for the films was found to be $400^{\circ}C$ from the optical properties. It is observed that the CdS film annealed at $400^{\circ}C$ reveals the strongest UV emission intensity and narrowest full width at half maximum among the temperature ranges studied. The enhanced UV emission from the film annealed at $400^{\circ}C$ is attributed to the improved crystalline quality of CdS thin film due to the effective relaxation of residual compressive stress and achieving maximum grain size. The results show that heat treatments under optimal annealing condition can provide significant improvements in the properties of CdS thin films.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.102-107
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• 2002

This study deals with a physical properties of Larch(Larix kaemferi Carr.) treated at temperatures above 100℃. Treatment conditions of this experiment were operated at regular intervals of 20℃ at temperature up to 180℃ for 10, 30, 60 and 90 minutes by using the bomb, respectively. The results of this study were as follows : 1) The density was decreased with increasing the times and temperatures of steaming. 2) It was considered that the steaming treated specimen's higher shrinkage compared to control was due to change of composition and structure in cell wall. 3) The warpage of half edge grain specimen was decreased by high temperature steaming.