• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.80-80
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• 1999

플라즈마 디스플레이 패널(PDP)의 공정을 간단히 하기 위하여 포토레지스트, ITO, 격벽재료를 Ar+ laser(λ-514 nm, CW)와 Nd:YAG laser(λ=532, 266nm, pulse)로 직접 패터닝 하였다. 레이저에 의한 포토레지스트의 패턴결과, 아르곤 이온 레이저의 포토레지스트 가공의 반응 메카니즘은 레이저 빔의 열에 의한 시료 표면의 국부적인 온도상승에 의한 용융작용이며, 그 결과 식각 후 형성된 패턴의 단면 모양도 레이저빔의 profile과 같은 가우시안 형태를 나타낸다. Nd:YAG 레이저의 4고조파(532nm)를 이용한 경우 200$\mu\textrm{m}$/sce의 주사속도에서 포토레지스트를 패턴하기 위한 임계에너지(threshold energy fluence) 값은 25J/cm2이며, 약 40J/cm2의 에너지 밀도에서 하부기판의 손상이 발생하기 시작하였다. 글미 1은 Nd:YAG 레이저 4고조파를 이용하여 포토레지스트를 식각한 경우 SEM 표면사진(위)과 단차특정기에 의한 단면형상(아래)이다. ITO 막의 레이저에 의한 직접 패턴 결과, ITO 막은 레이저 펄스에 의한 급속 가열 및 증발에 의한 메커니즘으로 식각이 이루어지며, 레이저 파장에 따른 광흡수 정도의 차이에 의해 2고조파 (532nm)에서 ITO 막의 가공 품질이 4고조파(266nm)에 비해 우수하며 패턴의 폭도 출력에 따라 제어가 용이하였다. 그림 2는 Nd:YAG 레이저 2고조파를 이용하여 ITO를 식각한 경우 SEM표면 사진(위)과 단차측정기에 의한 단면형상(아래)이다. 격벽 재료의 레이저에 의한 직접 패턴 결과, Ar+ 레이저(514nm)는 출력 밀도 32NW/cm2에서 격벽을 유리 기판의 경계면까지 식각하였다. Nd:YAG 레이저(532nm)는 laser fluence가 6.5mJ/cm2에서 격벽을 식각하기 시작하였으며, 19.5J/cm2에서 유리기판의 rudraus(격벽 두께 130$\mu\textrm{m}$)까지 식각하였다.

• Journal of Conservation Science
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• v.36 no.5
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• pp.368-382
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• 2020

It was confirmed that a white porcelain figurine in underglaze iron was damaged after exhibition. This study analyzes the current state of salt damage on the artifact and identifies the factors contributing to its deterioration by examining the material characteristics of the artifact and exhibition environment. The analysis will thus assist in preparing a conservation scheme for artifacts. The crystallized carbonate on the surface of the white porcelain figurine is a water-soluble alkali salt with high hygroscopicity and high solubility in water. This solubility increases as the temperature increases. The figurine was low-fired at approximately 1000℃. A lead glaze was applied, and thin cracks were formed on the glazed surface, indicating poor surface properties. Our analysis suggested that the showcase used in the exhibition likely created a moist environment resulting from condensation, as it was exposed to high temperature and relative humidity, particularly in comparison to the exhibition room where the temperature was regulated using an air conditioner. In addition, the artifacts in the showcase were exposed to sudden changes in temperature and relative humidity as the air conditioner was repeatedly turned on and off. Therefore, it can be deduced that the soluble salt remaining on the white porcelain figurine moved toward the surface of the relatively weak glaze as a result of the temperature, and the crystallized salt exacerbated surface damage as the moisture evaporated in a dry environment.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.1
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• pp.1-11
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• 2018

In this study, pro-oxidant($d2w^{(R)}$) and rPP/ZnO nanocomposite flexible films for food packaging were prepared, and their mechanical and antimicrobial properties were investigated. As a result, the carbonyl index and hydroxyl index increased with exposured time to heat and UV rays. Surface analysis showed that the addition of zinc oxide improved the dispersibility and compatibility of the polymer, so that the surface of the composite film was smooth and the zinc oxide particles were smaller than the compared film. And it kept the physical properties by heat and UV ray blocking effect, and it worked to reduce decomposition. In the antimicrobial activity test, the microbial reduction rate was 3 logs or more at the use concentration of zinc oxide. The tensile strength was increased and the elongation was decreased. Oxidative degradability of multi-layered film in UV exposured for 72 hours, the molecular weight of the film decreased by 75.6%, 1,294 g/mol Mn and 5,920 g/mol Mw. In the safety analysis of food packaging materials, we obtained that are in standard of polypropylene, a food contact material of domestic law.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.107-113
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• 2017

To understand of the present state for temperature management of cold and frozen food transportation vehicles, we surveyed and measured the temperatures of eight transportation vehicles (including 3 small & medium and 5 large businesses) in Jeonbuk province, Korea. In the transportation vehicles of small & medium businesses, the mean temperature of cold and frozen foods was $8.35{\pm}5.72^{\circ}C$ and $-3.45{\pm}16.88^{\circ}C$; in large businesses, $3.92{\pm}1.44^{\circ}C$ and $-15.38{\pm}2.98^{\circ}C$, respectively. In the difference of temperature by the locations within transportation vehicles, the difference in each cold and frozen was $2.40{\pm}1.45^{\circ}C$ and $2.37{\pm}2.52^{\circ}C$, as a mean. But there was not statistically significant difference in locations between cold and frozen (p > 0.05). In the difference of surface temperatures on various foods before and after door opening during the loading, the temperatures of cold and frozen foods increased by $0.55^{\circ}C$ and $1.18^{\circ}C$, as means, respectively. The temperature of foods over time and placement of cold and frozen foods in transportation vehicles were not consistently maintained at optimal values in distribution. Therefore, the development of time-temperature history (TTH) system technology at the distribution level for cold and frozen foods is required.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.4
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• pp.333-340
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• 2011

Purpose: The aim of this study was to study the effect of hydroxyapatite (HA) coating crystallinity on the proliferation and differentiation of human osteosarcoma cells. Materials and methods: Surface roughness of the titanium disks increased by anodizing treatment and then HA was coated using ion beam-assisted deposition (IBAD). HA coating was crystallized by heat-treated at different temperature ($100^{\circ}C$, $300^{\circ}C$, $500^{\circ}C$, $800^{\circ}C$). According to the temperature, disks were divided into four groups (HA100, HA300, HA500, HA800). With the temperature, crystallinity of the HA coating was different. Anodized disks were used as control group. The physical properties of the disk surface were evaluated by surface roughness tests, XRD tests and SEM. The effect of the crystallinity of HA coating on HOS cells was studied in proliferation and differentiation. HOS cells were cultured on the disks and evaluated after 1, 3, 5, and 7 days. Growth and differentiation kinetics were subsequently investigated by evaluating cell proliferation and alkaline phosphatase activity. Results: Regardless of the heat-treated temperature, there is no difference on the surface roughness. Crystallinity of the HA was appeared in the groups of HA500, HA800. HOS cells proliferation, ALP activity were higher in HA500 and HA800 group than HA100 and HA300. Conclusion: Within the results of this limited study, heat treatment at $500^{\circ}C$ of HA coating produced by IBAD has shown greater effect on proliferation and differentiation of HOS cells. It is considered that further in vivo study will be necessary.

• Applied Biological Chemistry
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• v.33 no.4
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• pp.293-300
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• 1990

The physical and chemical properties of dry acorn starch(DS), defatted acorn starch (DFS) and reincorporated acorn starch(RIS) were investigated. Swelling power and solubility of all starch sample, were exhibited two stage behavior. It had a little change on the pasting temperature of DS and DFS but the peak viscosity and breakdown value of DFS was somewhat higher than those of DS and RIS. Flow behavior of gelatinized starch pastes showed a pseudoplastic behavior and flow behavior index was lower than unit The consistency coefficient showed concentration and temperature dependency. The activation energies of DS, DFS and RIS were from $1.70Kca1/g\;{\cdot}\;mol$ to $3.75Kca1/g\;{\cdot}\;mol$.

• Korean Journal of Food Science and Technology
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• v.23 no.6
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• pp.723-731
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• 1991

In order to optimize sterilization conditions of retort pouched curry sauce, sterilization processes for eighteen conditions by varying temperature, time and method were conducted through $3^{2}{\times}2^{1}$ experimental factorial design. Quality evaluations before and after sterilization included measurements of vitamin (niacin) retention, pH and color differences, and organoleptic test(taste, color and viscosity). $F_{o}$ values were also measured at each condition. Product qualities were mainly affected by sterilization temperature and time, whereas sterilization method had no significant effect. Effect of sterilization time on product qualities was higher than that of sterilization temperature. From the response surface analysis, an optimum range of sterilization condition simultaneously satisfying desired specifications was determined to be $123.5^{\circ}C$, 21.5 min to $127.5^{\circ}C$, 17.0 min. In this range, the sterility($F_{o}$ value) at a cold point during sterilization was approximately 15.0 min.

• Journal of the Korean Electrochemical Society
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• v.2 no.3
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• pp.117-122
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• 1999

This study investigated the corrosion rate of aluminum in alkaline solution. It was performed to observe the effects of alloy element, alkalinity (KOH concentration), solution temperature, and inhibitor and its concentration in the solution. Among species of aluminum, AA-1050 showed the lowest corrosion rate due to its high purity $(>199\%)$, whereas alloys containing Mg anuor Mn were highly corroded, relatively. The corrosion rate could be reduced over than $50\%$ by saturating the solution with ZnO, while ZnAc did not work as an inhibitor. The inhibition effect of ZnO increased with increasing the alkalinity and solution temperature. It was found that the corrosion rate linearly increased with the concentration of KOH in first order and exponentially decreased with the inverse of the solution temperature. An analysis of the corroded material covered the surface of aluminum was made by SEM and EDS. According to the analytical results by using XRD, it was confirmed that $Al(OH)_3$ was produced from the corrosion of aluminum in KOH solution.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.2
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• pp.197-206
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• 2010

Recently, developed countries have continuously been trying to recognize many issues about heat island in urban area and to make up countermeasures for them. This research is designed to extract change of land cover in the area under condition of land development with satellite images and to analyze its effect on the heat change in there. Heat change upon change of land cover in daejeon was analyzed with the four Landsat satellite images taken in April 1985, August 1994, May 2001, and May 2009. In order to measure the temperature on the surface in the city, the land surface temperature was produced with Landsat TM Band 6. Heat change is to detected with it. As a result, The urban area has been increased up to 23.59 percent. On the other hand, the forest area has been decreased up to 27.91%. Due to the urbanization, the temperature on the surface in urban center was higher than surrounding area. In that case, the temperature of urban center area was higher 2.4 to $5.7^{\circ}C$ compared with the forest area.

• Elastomers and Composites
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• v.44 no.1
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• pp.63-68
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• 2009

Recently, much attention has focused on the permanent deformation of roads in hot summer and cracks in cold winter, which are detrimental to safe driving. This leads to necessity of modification of asphalt to resist those deformation. In this study, a type of modified asphalt was prepared by addition of a photoinitiator which is activated by ultraviolet lay. The mechanical and rheololgical properties of photoinitiator-modified asphalt were examined using UTM and rheometer. Results showed that the modified asphalt was effected by ultraviolet and thus tensile strength and storage modulus increased, due to molecular attraction, with initiator content and irradiation dose. Thermal analysis showed less weight loss upon photoinitiator-modification and this indicated that the molecular attraction is the result of cross linking reaction between asphalt molecules induced by photoinitiator. According to long term ultraviolet curing test, properties of the photoinitiator-modified asphalt did not decrease or even increase for 20 years. This indicates that useful life of the asphalt could be extended by addition of photoinitiator.