• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.40-40
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• 2008

$InGaZnO_4$ based thin film transistors (TFTs) are of interest for large area and low cost electronics. The TFTs have strong potential for application in flat panel displays and portable electronics due to their high field effect mobility, high on/off current ratios, and high optical transparency. The application of such room temperature processed transistors, however, is often limited by the operation voltage and long-tenn stability. Therefore, attaining an optimum thickness is necessary. We investigated the thickness dependence of a room temperature grown $MgO_{0.3}BST_{0.7}$ composite gate dielectric and an $InGaZnO_4$ (IGZO) active semiconductor on the electrical characteristics of thin film transistors fabricated on a polyethylene terephthalate (PET) substrate. The TFT characteristics were changed markedly with variation of the gate dielectric and semiconductor thickness. The optimum gate dielectric and active semiconductor thickness were 300 nm and 30 nm, respectively. The TFT showed low operating voltage of less than 4 V, field effect mobility of 21.34 cm2/$V{\cdot}s$, an on/off ratio of $8.27\times10^6$, threshold voltage of 2.2 V, and a subthreshold swing of 0.42 V/dec.

• 한국지역사회생활과학회지
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• 제16권4호
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• pp.15-24
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• 2005

We investigated the changes of volatile flavor components from Codonopsis lanceolata, which were packed in woven polypropylene(WP) film or low density polyethylene(LDPE) film and stored for 15 and 30 days at refrigerated($2{\∼}4^{\circ}C$ ) or room($18{\∼}20^{\circ}C$) temperature. A hundred and sixty seven volatile flavor components in the fresh C. lanceolata were identified by GC/MS analysis. When determining the flavor components from C. lanceolata cultivated on a wild hill and stored at 4 conditions for 30days, six volatile components such as 1-hexadecene, 2,6-dimethyl-2-octanol, 2-methyl-2-dodecanol, $\alpha$-guaiene, $\delta$-cadinene and trans-2-hexen-1-ol were detected as common components of all stored samples, and The types of common flavor components of C. lanceolata were different according to storage conditions. The numbers were 16 from refrigerated, 7 from room temperature stored, and 10 components from WP or LDPE packed conditions, respectively. The total peak area ratio of the major 10 compounds were $52.0{\∼}86.8\%$, and the percentage of trans-2-hexen-1-ol, which was the only common compound among the major 10 components, was the highest as $26.4{\∼}68.1\%$ The major flavor profile, describe by highly trained panel, were green, aldehydic, earthy and camphoreous. As the result from sensory evaluation, the freshness of C. lanceolata was maintained better by controlling storage temperature rather than selection of package materials. The best condition for characteristic flavor of C. lanceolata was packing with LDPE and chilling.

• Composites Research
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• 제24권2호
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• pp.30-37
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• 2011

에폭시 수지와 유리섬유직물 간의 젖음성을 분석하였다. 에폭시 수지와 산무수물 경화제의 혼합비는 당량비 1:0.5, 1:1, 1:1.2로 하였고, 촉매는 혼합된 수지의 0.lwt%로 첨가하였다. DSC 경화거동분석 결과 이 혼합 수지는 상온에서 함침이 가능하였다. 혼합 수지에 대해 유리평판에 놓여진 유리섬유직물 위에 수지 한 액적(방울)을 투하 후 시간에 따른 접촉각 변화를 측정하였다, 또한, 일정량의 에폭시 수지 액적을 투하시켜 시간에 따른 젖음면적 변화를 측정하였다, 접촉각, 액적높이, 순수 젖음면적, 젖음계수를 측정함으로써 유리섬유직물에 대한 에폭시 수지의 젖음성을 비교 평가하였다. 그 결과 당량비 1:1.2에서 유리섬유직물에 대한 젖음성이 가장 우수하였다.

• Journal of Pharmaceutical Investigation
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• 제27권1호
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• pp.39-49
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• 1997

Nicotinic acid was mixed with glass powders such as controlled pore glass (CPG), glyceryl controlled pore glass (GPG) and glass beads (GB) at room temperature. The physicochemical properties of nicotinic acid in the various mixtures were examined by differential thermal analysis, X-ray diffraction study. Infrared spectroscopy and BET gas adsorption measurements. The peak area at the melting point from the various mixtures of nicotinic acid and CPG was increased with an increase of nicotinic acid concentration while the broad peak area was remained unchanged in the DTA curve. As shown in the powder X-ray diffraction patterns, the crystalline peaks of nicotinic acid disappeared in mixture with CPG, suggesting the interaction of nicotinic acid and porous powders. It was found that the larger the content of CPG, the higher the ratio of an amorphous state to a crystalline state. BET isotherm showed that as the amount of nicotinic acid was increased, the specific surface area was reduced proportionally to nicotinic acid content of up to 40% and remained constant thereafter. Sublimation of nicotinic acid from the mixture of nicotinic acid and CPG was examined. A large quantity of nicotinic acid was retained in the mixture when stored on various temperatures in vacuo for 10 hours. The nicotinic acid mixtures with CPG or GPG showed a high dissolution rates of nicotinic acid in aqueous solution, especially in the initial dissolution stage. CPG is expected to be a good pharmaceutical excipient to reduce the crystallinity of drugs and to prevent sublimation of drugs.

• Corrosion Science and Technology
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• 제17권3호
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• pp.138-145
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• 2018

The aim of this work is the attainment of the $TiO_2-nanotube$ photocatalytic-growth condition using anodization, whereby the $NH_4F-H_2O$ weight ratio is appropriately controlled. We fabricated the $TiO_2$ nanotubes using a two-step anodization (first step is 1 hr; second step is 30 hr) under the ambient pressure and the room temperature at 60 V in ethylene-glycol solutions to investigate the effects of the $NH_4F$(0.1,0.3,0.5wt%) and $H_2O$(1-3wt%) on the $TiO_2-nanotube$ geometry and the photocatalytic efficiency. Further, the decomposition efficiency of the methylene blue on the $TiO_2$ nanotubes by the UN radiation depended on the geometrical change of the nanotube geometry, indicating the proportionality of the decomposition efficiency to the surface area that was affected by the $NH_4F$ and $H_2O$ concentrations. As the $NH_4F$ weight was increased, the surface area initially decreased but slightly increased later, and the length consistently increased. As the $H_2O$ weight was increased, the surface area and length initially increased, but later decreased with the 3 wt% $H_2O$.

• 한국태양에너지학회 논문집
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• 제26권3호
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• pp.89-97
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• 2006

Our Housing culture continuously changes for the correspondence to social development and changes of economy, and be developing. A massive apartment complex continuously increased, and According to this in our country heating energy consumption of a residential building is continuously increasing at country me whom was limited in order to raise efficient residential land use and diffusion ratio of house. If confirm an element to be able to reduce use of a heating energy, and there is saving possibility to parts of energy saving, this study will present the standard amount used with bases to the gas amount used for heating and Field Test data about room temperature. Execute simulation with building balance (public area, a plain), the gas amount useds such as incense of a building, indoor setting temperature ($^{\circ}C$), a position of an apartment house etc. to affect the energy amount used of a valuation object building of a variable through Field Test and research on the actual condition. Calculate the standard amount used of city gas for winter season heating of a comparative analysis apartment house to data value getting the above results through Field Test and simulations with bases.

• 한국세라믹학회지
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• 제38권4호
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• pp.307-307
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• 2001

Combustion process with citrate was used to produce the LiMn$_2$O$_4$powder. Precursors are pre-ignited in open air followed by post-heating in the range from $600^{\circ}C$ to 80$0^{\circ}C$ for 4h. With varying the molar ratio (R) of ethylene glycol (EG) to citric acid (CA) from 0 to 4, the effect of EG content on powder characteristics is evaluated. Vacuum drying promote the auto-ignition at room temperature. With small addition of EG metal ion was selectively segregated with organic substances and undesired lithium evaporation occurred during post-heating. LiMn$_2$O$_4$phase which is produced by combustion reaction was decomposed back to Mn$_3$O$_4$because the reaction temperature was higher than 95$0^{\circ}C$. With increasing EG content, the homogeneity of LiMn$_2$O$_4$powder increased and specific surface area increased. And lithium evaporation during vacuum drying and/or ignition also increased.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2004년도 춘계학술발표대회 논문집
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• pp.100-105
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• 2004

Recently, the assisted living facilities for the elderly are increasing due to the facts, such as rapid increasing ratio of old people, rising incomes and the changing concepts towards family relationship. For the elderly, there is a need to re-examine how environment can incorporate design concepts which enhance accessibility and adaptability. For this survey each seven cases in Korean & American facilities were examined and also 120 copies of a questionnaire for the elderly who are above 60 were analysed. This survey revealed that; 1. The consciousness of the majority elderly was favorably aware of the assisted living facilities for the elderly by a social phenomenon. 2. At a response of the scale for the living unit, majority subjects preferred to live in size of 16${\sim}$20 pyung. 3. Subjects preferred not only clean and modern atmosphere, but also medical area and fitness room, design considerations for these points are needed. 4. Enough spaces for their hobbies and social activities, which are important factors for smooth understanding, communication and psychological remedy effect for the elderly should be provided in the facilities for the elderly. 5.Korean facilities were lack of accessibility, safety and adaptability, thus it is very important to select the suitable materials for the safety and lighting plans with regard to their physical and mental qualities.

• 한국안전학회지
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• 제29권5호
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• pp.15-21
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• 2014

The aim of this work is conduct the study on light weight and structural performance improvement of the composite wind power blade. GFRP (Glass Fiber Reinforced Plastic) pre-empted by CFRP(Carbon Fiber Reinforced Plastic), the major material of wind power blade, was identified the superiority of mechanical performance through the tensile and fatigue test. SENT(Single Edge Notched Tension) specimen fracture test was conducted on the specimen that laminated together 2 ply CFRP with 4 ply GFRP through DIC(Digital Image Correlation) analysis. The SENT specimen thickness and $a_0/W$ ratio is 1.45 mm and 0.2, respectively. The fracture test accomplished with displacement control with 0.1 mm/min at the room temperature. The experimental apparatus used for the fracture test consisted of a 50kN universal dynamic tester and CCD camera connected to a personal computer (PC), which was used to record images of the specimen surface. Following data acquisition, the images and load-displacements were transferred to the PC, on which the DIC software was implement. The experiment and DIC analysis results show that CFRP/GFRP laminated composite exhibits improvement of the strength, compared with that of the existing blade material. This study shows the result that the strength of CFRP rotor blade of wind turbine satisfies through the experimental and DIC method.

• 한국전기전자재료학회논문지
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• 제18권2호
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• pp.159-163
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• 2005

This paper gives characterization of ZnO thin film deposited by RF magnetron sputtering method, which is concerned in deposition process and device fabrication process, to fabricate solidly mounted resonator(SMR)-type film bulk acoustic resonator(FBAR). A piezoelectric layer of 1.1${\mu}{\textrm}{m}$ thick ZnO thin films were grown on thermally oxidized SiO$_2$(3000 $\AA$)/Si substrate layers by RF magnetron sputtering at the room temperature. The highly c-axis oriented ZnO thin film was obtained at the conditions of 265 W of RF power, 10 mtorr of working pressure, and 50/50 of Ar/O$_2$ gas ratio. The piezoelectric-active area was 50 ${\mu}{\textrm}{m}$${\times}$50${\mu}{\textrm}{m}$, and the thickness of ZnO film and Al-3 % Cu electrode were 1.4 ${\mu}{\textrm}{m}$ and 180${\mu}{\textrm}{m}$, respectively. Its series and parallel frequencies appeared at 2.128 and 2.151 GHz, respectively, and the qualify factor of the resonator was as high as 401.8$\pm$8.5.