• 한국세라믹학회지
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• 제34권1호
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• pp.88-94
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• 1997

플라즈마 용사법(plasma spray method)으로 제작된 상용 가스 터빈 연소기의 finned segment의 열차폐용 코팅계, ZrO2-8wt%Y2O3 top coat/Ni-26Cr-5Al-0.5Y bond coat/Hastelloy X superalloy 기판에서 NiCrAlY bond coat의 산화 거동과 열피로 파괴에 대하여 조사하였다. 생성된 bond coat의 주산화물은 NiO, CrO2, Al2O3였다. ZrO2/bond coat계면에서 생성된 산화물의 분포는 고온에서의 사용 전에 이 계면 아래에 얇은 층의 Al2O3가없는 곳에서는 NiO 산화층 및에 Cr2O3와 Al2O3가 혼합된 형태를 나타내었다. 열피로에 의해 박리된 시편의 파면을 관찰한 결과, 파괴는 주로 ZrO2/산화층 계면보다 세라믹층내로 약간 치우쳐서 일어나지만, 산화층 내에서도 약간 일어남을 알 수 있었다.

• Journal of Plant Biology
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• 제29권4호
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• pp.295-315
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• 1986

Structure and differentiation mechanism of the seed coat of Panax ginseng are studied with light and electron microscopes to clarify the developmental processes of seed coat and the structural changes during the differentiation of the seed. The seed coat of ginseng is differentiated from the inner cell layers of ovary wall, which can be compared with the seed coat differentiated from integument(s) in other plants. The single integument is differentiated into endothelium, which is degenerated to one layer of 4${\mu}{\textrm}{m}$ in thickness, composed of remants of cell wall components in fully ripened seed. The ripened seed coat is composed of three layers; fringe layer, inner layer and palisade layer, and all of the them are crossed at right angles with one another. This may be the cause of protection of the kernel from other mechanical injuries. The thickness of fully ripened seed coat is about 300~600 ${\mu}{\textrm}{m}$, and arrangements of sclereids are irregular. However, the raphe region of seed coat is thin about 200 ${\mu}{\textrm}{m}$ in thickness and sclereids in that region are arranged regularly. This is the important cause for the cleavage of the seed coat during post-maturation process. The vascular bundles on the raphe are still remaining after sarcocarps are removed, and one of the branches of vascular bundles entered into the seed coat through the hilum and extended to chalazal region. During post-maturation process, the supply of water being necessary for growth of embryo may be accompolished by the vascular bundles entered into the seed coat through the opened hilum.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.784-791
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• 2022

Tack coat is a thin layer of asphalt between the existing pavement and asphalt overlay. During construction, insufficient tack coat layering can later cause surface defects such as slippage, shoving, and rutting. This paper proposed a method for tack coat inspection improvement using an unmanned aerial vehicle (UAV) and deep learning neural network for automatic non-uniform assessment of the applied tack coat area. In this method, the drone-captured images are exploited for assessment using a combination of Mask R-CNN and Grey Level Co-occurrence Matrix (GLCM). Mask R-CNN is utilized to detect the tack coat region and segment the region of interest from the surroundings. GLCM is used to analyze the texture of the segmented region and measure the uniformity and non-uniformity of the tack coat on the existing pavements. The results of the field experiment showed both the intersection over union of Mask R-CNN and the non-uniformity measured by GLCM were promising with respect to their accuracy. The proposed method is automatic and cost-efficient, which would be of value to state Departments of Transportation for better management of their work in pavement construction and rehabilitation.

• KCI Concrete Journal
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• 제13권2호
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• pp.58-66
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• 2001

Recently, polymer-modified mortar has been studied for proposed use on industrial floors as top coat with thin thickness, typically 5~15mm. The purpose of this study is to evaluate basic properties of self-leveling materials using polymer dispersions as kinds of SBR, PAE, St/BA with thin coat (under 3mm). Superplasticizer and thickener have been included in the mixes to reduce bleeding and drying shrinkage as well as to facilitate the workability required. The self-leveling materials using four types of polymer dispersion are prepared with polymer-cement ratio which respectively range from 50% and 75%, and tested for basic characteristics such as unit weight, air content, flow, consistency change and adhesion in tension. From the test results, the self-leveling materials using PAE emulsion at curing age of 28days are almost equal to those of conventional floor using urethane and epoxy resin. The adhesion in tension of self-leveling mortars using SBR latex and PAE emulsion at curing age of 3days is over 17 kgf/cm$^2$(1.67MPa). Consistency change is strongly dependent on the type of polymer dispersion. It is concluded that the self-leveling materials using polymer dispersions can be used in the same manner as conventional floor using thermosetting resin in practical applications, in the selection of polymer dispersions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1344-1347
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• 2004

Recently, Study on measuring property of a micro thin film(nm ～ hundreds of ) under Thermal Mechanical loading. In this work, We perform tensile test at high temperature(1200 ) to investigate mechanical properties of alumina TGO formed under Thermal Barrier Coating. We used Digital Image Correlation method for measuring displacement, and We presented a method of tensile test for thin film at high temperature.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2009년도 춘계학술대회 논문집
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• pp.151-152
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• 2009

We coated $TiO_2$ thin films on particles by a rotating cylindrical plasma chemical vapor deposition (PCVD) process and investigated the effects of various process variables on the morphology and growth of thin films. The polypropylene (PP) particles were rotated with the cylindrical PCVD reactor and they were coated with $TiO_2$ thin films uniformly by the deposition of thin mm precursors in the gas phase. The $TiO_2$ thin films were coated on the PP particles uniformly and the thickness of thin films almost proportional to the deposition time. The $TiO_2$ thin films grew more quickly on the PP particles with increasing rotation speed of the reactor. This study shows that a rotating cylindrical PCVD reactor can be a good method to coat high-quality $TiO_2$ thin films uniformly on particles.

• 대한한의학회지
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• 제20권2호
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• pp.187-197
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• 1999

To assess the usefulness of tongue inspection for evaluating the Pattern identification in oriental medicine, we observed stroke patient's tongue and tongue coat and compared it with Pattern identification. The test group was composed of 85 acute stroke stage patients(within 72 hours of onset). Subjects were randomly selected from stroke patients admitted in the KyungHee University, Hospital of Oriental Medicine from December 1 1998 to June 30 1999. We took pictures of patient's tongue and tongue coat within 72hours from onset and checked Pattern identification at the same time. Tongues colored pale rose or red greatly outnumbered other colors. Tongue shape tended to be prickly or fissured, and tongue condition tended to be unflexible or deviated. Regarding tongue coat color, there were great amounts of yellow or clark yellow tongue coats, which were moist, thick or greasy in substance. The red tongue was significantly related to Fire-heat and deficiency of Yin syndrome, while faint white tongue to Damp syndrome(P=0.006). In terms of tongue coat, thin coat was related to Wind and Fire-heat syndromes, thick coat to Damp and Blood stasis syndrome, respectively (P=0.002). In conclusion, we thought that tongue inspection could be a useful Oriental medicine diagnosis in stroke.

• 소성∙가공
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• 제13권8호
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• pp.716-722
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• 2004

Effects of sliding speed, applied load, and thickness of PMMA (Poly Methyl Methacrylate) coating layers on their dry sliding frictional and wear behavior were investigated. Sliding wear tests were carried out using a pin-on-disk wear tester. The PMMA layer was coated on Si wafer by a spin coating process with two different thicknesses, $1.5\mu\textrm{m}$ and $0.8\mu\textrm{m}$. AISI 52100 bearing steel balls were used as a counterpart of the PMMA coating during the wear. Normal applied load and sliding speed were varied. Wear mechanisms of the coatings were investigated by examining worn surfaces using an SEM. Friction coefficient of the coatings decreased with the increase of the applied load. Both adhesion and deformation of the coating determined the coefficient. The thicker PMMA layer with the thickness of $1.5mutextrm{m}$ showed lower friction coefficient than the thinner layer under most test conditions. Effects of sliding speed and applied load on the frictional behavior were varied depending on the thickness of the coating layer.

• 한국소음진동공학회논문집
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• 제11권4호
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• pp.31-36
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• 2001

A spin coater is a machine to coat wafer or LCD display with thin film. Vibration in the spin coater may be one of main troubles in the coating process. In this paper, we focus on the difference between two spin coaters. Vibration sources are identified by experimental approach and are compared to find the difference between the two spin coaters. Also, the particle concentration is observed by laser particle counter (LPC) for the two spin coaters, when the spin coaxers are working. It is also considered whether the defect rate is proportional to the particle concentration. The result shows that particle generation in the coating process is related to excessive vibration of the spin coater shaft and the particles influence the defect rate of the thin film product.

• 한국정밀공학회지
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• 제31권6호
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• pp.491-495
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• 2014

We developed a compact high-precision slot-die coating machine for thin-film deposition on a flexible substrate. For smooth and precise coating, air-bearing and linear motor system were employed to minimize velocity ripple. The gap control mechanism is specially designed to have repeatability of gap between nozzle and substrate under 1 ${\mu}m$. Due to extremely precise gap control, the machine can coat thin-films down to 50 nm with $200mm{\times}100mm$ size. A thin film of Ag nano-particle ink is coated for demonstration.