• 한국의류산업학회지
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• 제10권6호
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• pp.989-996
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• 2008

The purpose of this study is to provide the basic knowledge for the pattern development of a flared skirt. Two flat pattern (FP) methods, the concentric circle method and the corrected concentric circle method, and a draping were used for pattern making. Using these patterns, skirts were made with lengthwise grain in the centerline. The influence of pattern making method on the silhouette of the flared skirt was evaluated by the hemlines formed at the skirt worn in a dress form. Moreover, the combined influence of pattern making method and cutting direction on the silhouette of the flared skirt was examined with the draping pattern (DP) skirt and a FP skirt with $45^{\circ}$ bias grain in the centerline. The DP skirt had more uniform nodes and formed a stable wave form than the FP skirts throughout the whole hemlines. The number of nodes was reduced with lining in the two FP skirts, whereas the number of nodes was not changed in the DP skirt. The unit wave form of all the skirts by three patterns showed long loop form, and the slope angles of the unit wave form of the two FP skirts were higher than that of the DP skirt. The silhouette of the flared skirt was highly influenced by the shape of the waist circumference line in patterns. The DP skirt with lengthwise grain in the centerline showed good silhouette with uniform nodes and high marking efficiency, compared to the FP skirt with $45^{\circ}$ bias grain in the centerline.

• Journal of the Korean Wood Science and Technology
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• 제21권3호
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• pp.45-52
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• 1993

Surveyed results on the slope of grain and the twist of sawn lumber of Pinus koraiensis, Larix leptolepis, and Pinus densiflora were summarized as follows: 1. The slope of grain of Pinus koraiensis has a Z-grain in the stem axis. The slope of grain was found to be the lowest at near to the pith and then constantly increased. At the height of 0.2m from the base of stem. a cross section of 35 annual rings was found to have a repeatedly increasing and decreasing slope of grain and then constantly decreased. At the height of 1.2m to 7.2m from the base of stem, the slope of grain increased conspicuously until the 10th annual ring, after which it increased near to the bark with repeatedly increasing and decreasing trends. 2. Pinus densiflora has a S-grain in the stem axis. The lowest slope of grain was found at near to the pith, and the highest in the 10 to 35 annual rings from the pith. 3. Larix leptolepis has a S-grain. At the height of 3.2m from the base of stem, the big fluctuation of the slope of grain was found without any particular trend. 4. The slope of grain and the twist between natural and reforested timber of Pinus koraiensis were found to be almost the same trend in viewpoint of the annual ring. The maximum slope of grain of imported Siberian timber of Pinus koraiensis was found at the 10 annual rings, which was quite similar to that of native species in Korea, but the big difference of the twist was found at 140 annual rings. 5. The twist was little at the mature wood of reforested Pinus koraiensis and Siberians and the duplicated part of mature and juvenile woods of those. On the contrary, the twist was great at the duplicated part of mature and juvenile woods of Pinus koraiensis. 6. The twist of Larix leptolepis showed the S-direction which coincided with that of slope of grain. The twist was greatest at the part of juvenile wood and little at the duplicated part of mature and juvenile woods, and little difference of twist was found between mature and juvenile woods. 7. Siberian larix having a minimum slope of grain showed the lowest twist, and the twist at the duplicated part of mature and juvenile woods showed a middle level of both mature and juvenile woods' portions.

• 한국재료학회지
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• 제4권7호
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• pp.750-758
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• 1994

본 연구에서는 반구형(HSG) 다결성 실리콘 박막을 제조하여 박막에 존재하는 결정립들의 특성과 각 결정립들의 형성기구를 예측하고자 하였다. LPCVD법으로 실리콘 박막을 증착하여 미세구조를 관찰, 분석한 결과 $575^{\circ}C$ 증착온도에서 HSG 다결정 실리콘 박막이 형성되었음을 관찰하였다. 이 HSG 박막은 비정질 및 결정질 상으로 구성되어 있었으며 결정립은 박막의 표면에 존재하는 upper grain들과 $SiO_{2}$와의계면에 존재하는 lower grain들로 구분되었다. Upper grain은 실리콘 원자의 표면확산에 의하여 형성되었으며, lower grain은 고상성장에 의하여 형성되었다. 성장한 결정립들의 성장방위를 분석한 결과 주로 upper grain은 <110>, lower grain은 <311>과 <111>방위를 나타내었다. 이러한 방위관계는 각 결정립들의 형성기구(formation mechanism)의 차이에 기인한다고 사료된다. 또한 HSG박막의 미세구조와 진공열처리한 시편을 관찰한 결과 HSG 박막의 형성은 실리콘 원자의 표면확산에 의해 지배됨을 알았다.

• 한국세라믹학회지
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• 제29권11호
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• pp.912-918
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• 1992

Microstructure evolution including morphological change in the vicinity of the electrodes, porosity change and grain boundary migration was observed in polycrystalline CoO subject to electric fields at 1100 and 121$0^{\circ}C$ in air. At the cathode, the transported cations react with oxygen in the surrounding to form new lattices, while, at the anode, the reverse reaction occurs leading to lattice annihilation. Lattice formation also takes place at the surface of pores near the cathode inducing pore-filling effect. Grain boundary migration was found bo be enhanced or retarded depending on the field direction. It is therefore implied that the driving force of grain boundary migration is the vectorial sum of the curvature-induced chemical potential gradient and the electric field applied.

• 대한기계학회논문집A
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• 제32권9호
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• pp.713-719
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• 2008

Most of the MEMS parts are made of multi-grain silicon wafer, which is the orthotropic material and its material direction is arbitrary. The reliability of the parts must be guaranteed in order to use for the commercial usage. The need of the structural analysis of its parts emerges an important factor. The material properties of the MEMS parts are calculated by the numerical method in order to reduce a material test. In this study, the effective elastic modulus and its Poisson's ratio are calculated by the boundary element method(BEM) and are compared with the results by the finite element method(FEM).

• 한국전기전자재료학회논문지
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• 제33권2호
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• pp.114-117
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• 2020

In this study, we performed the deposition of Al thin film using a DC magnetron sputtering method. To evaluate electrical and structural properties, the growth conditions were changed in terms of two functions, namely, sputtering power ranging from 41.6 to 216 W and film growth rate ranging from 5.35 to 26.39 nm/min. The growth rate and the microstructure were characterized by a scanning electron microscopy and X-ray diffraction analysis. The plane of crystalline growth showed that the preferential (111) direction and defects due to the grain boundary increased with DC power. The resistivity of the Al film over 50 nm showed a constant value by horizontal grain growth. Our results can be applicable for the preparation of nano-templates for anodic aluminum oxide.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.88-95
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• 2001

Silicon nitride based ceramics reinforced with 3wt% Si$_{3}$N$_{4}$ whisker was prepared by tape casting to investigate the effect of microstructure on erosion behaviors. Hardness and fracture toughness were measured with prepared specimens. A gas blast type erosion tester was used to examine the erosion behavior of the specimens with different impact directions and angles. The erosion rate increases with increasing impact angle. Erosion rate of the silicon nitride ceramics also depends on the grain orientations, The erosion rate was lowered when impaction direction was parallel to the grain orientation This result was explained by the crack deflection and bridging due to the grain orientation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.263-265
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• 2009

In this study, ultrafine grained (UFG) oxygen free high conductivity copper (OFHC Cu) having two different grain morphologies, one the severely elongated and the other the equiaxed, was prepared by equal channel angular pressing (ECAP) with routes A and $B_c$, respectively. The results of quasi-static tensile tests at $10^{-1}\;s^{-1}$ and $1\;s^{-1}$ and dynamic compression tests at $10^3\;s^{-1}$ order revealed that the equiaxed UFG Cu exhibited higher strength and less ductility compared to the elongated one. The difference of the plastic flow characteristics between the two were rationalized by considering their dislocation mean free length based on the orientation relationship between the possible slip planes and the loading direction.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권12호
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• pp.559-561
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• 2003

We report a new excimer laser annealing method which successfully results in a single grain boundary formation in the channel of polycrystalline silicon thin film transistor. The proposed method is based on lateral grain growth and employs aluminum patterns which act as selective beam mask and lateral heat sink. The maximum grain size obtained by the proposed method is about 1.6${\mu}{\textrm}{m}$ in the length. The grainboundaries should be arranged parallel with the direction of current flow for the best device performance, so we propose a new device fabrication method and a new poly-Si TFT structure. Poly-Si TFT fabricated by the proposed method exhibits considerably improved electrical characteristics, such as high field effect mobility exceeding 240 $cm^2$/Vsec.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1281-1282
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• 2007

Effect of tension coating on reducing iron losses of thin grain-oriented 3% Si-Fe steel sheets was investigated. Conventional grain-oriented electrical steel sheets have a forsterite coating layer and a tension coating layer in order to apply tensile stress to the rolling direction of the sheets. However the proposed coating method in this paper is to form only a tension coating layer on the both surfaces of the sheets. Iron losses with the tension coating were reduced by 8% under the condition of 1.7 T and 60 Hz. Consequently the proposed tension coating is applicable to $80{\mu}m$-thick 3% Si-Fe steel sheets.