• 한국세라믹학회지
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• 제37권7호
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• pp.665-672
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• 2000

The ferroelectric YMnO3 thin films were prepared by MOD(metal-organic decomposition) method with Y- and Mn-acetylacetonate as starting materials. Thin films were grown on various substrates by spin-coating technique. The crystalline phases of the thin films were identified by X-ray diffractometer as a function of heat-treatment temperature, pH of coating solution and substrate. In addition, the effect of Mn/Y molar ratio(0.8~1.2) on the formation of hexagonal-YMnO3 phase was investigated. In forming highly c-axisoriented hexagonal-YMnO3 single phase, the Pt coated Si substrate was more effective than the bare Si substrate, and the optimum heat-treatment condition was at 82$0^{\circ}C$ for 30 min. Higher Mn/Y molar ratio within 0.8~1.2 and pH of YMnO3 precursor solution within 0.5~2.5 favored formation of ferroelectric hexagonal phase rather than orthorhombic phase. Leakage current density of the hexagonal-YMnO3 thin film formed on Pt(111)/TiO2/SiO2/Si substrate was low enough as 0.4~4.0$\times$10-8(A/$\textrm{cm}^2$) at 5 V and its remanent polarization(Pr), calculated from the P-E hysteresis loop, was 3 nC/$\textrm{cm}^2$.

• 한국표면공학회지
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• 제36권1호
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• pp.9-13
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• 2003

Plasma polymerized organic thin films were deposited on Si(100), glass and metal substrates at $25∼100 ^{\circ}C$ using thiophene and toluene precursors by PECVD method. In order to compare physical and electrochemical properties of the as-grown thin films, the effects of the RF plasma power in the range of 30∼100 W and deposition temperature on both corrosion protection efficiency and physical properties were studied. We found that the corrosion protection efficiency ($P_{k}$), which is one of the important factors for corrosion protection in the interlayer dielectrics of microelectronic devices application, was increased with increasing RF power. The highest $P_{k}$ value of plasma polymerized toluene film (85.27% at 70 W) was higher than that of the plasma polymerized thiophene film (65.17% at 100 W), indicating inhibition of oxygen reduction. The densely packed and tightly interconnected toluene film could act as an efficient barrier layer to the diffusion of molecular oxygen. The result of contact angle measurement showed that the plasma polymerized toluene films have more hydrophobic surface than those of the plasma polymerized thiophene films.

• 한국산학기술학회논문지
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• 제7권6호
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• pp.1296-1301
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• 2006

눈은 자외선과 가시광선에 노출되어 있다. 눈은 자외선 노출에 해로우므로 모든 자외선으로부터 눈을 보호해야 한다. 본 연구에서는 자외선 차단을 위해 투명 플라스틱에 유-무기 하이브리드 재료와 자외선 흡수제의 배합에 의한 자외선 차단 코팅하였고, PMMA, CR 39 및 PC기재에 적용하여 자외선 차단 효과를 조사하였다. 자외선 흡수제의 양이 증가할수록 자외선의 투과도는 낮았다. PMMA의 경우 자외선 투과도를 현저히 감소시켰으며 CR 39에서도 자외선 차단 효과가 있는 것으로 나타났다. 한편, PC자체에서는 자외선 차단효과가 있는 것으로 평가되었다. CR 39 렌즈의 부착력, 내약품성, 내온수성은 우수하였고, 연필 경도의 경우 4H였으며 내마모성은 좋지 않았다.

• Archives of Pharmacal Research
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• 제25권4호
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• pp.397-415
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• 2002

This paper deals with a crucial mechanism for interaction of basic drugs and cardiac glycosides at the hepatic uptake level. Available literature data is provided and new material is presented to picture the differential transport inhibition of bulky (type2) cationic drugs by a number of cardiac glycosides in rat liver. It is shown that the so called organic anion transporting peptide 2 (oatp2) is the likely interaction site: differential inhibition patterns as observed in oocytes expressing oatp2, could be clearly identified also in isolated rat hepatocytes, isolated perfused rat liver and the rat in vivo. The anticipation of transport interactions at the hepatic clearance level should be based on data on the relative affinities of interacting substrates for the transport systems involved along with knowledge on the pharmacokinetics of these agents as well as the chosen dose regimen in the studied species. This review highlights the importance of multispecific tranporter systems such as OATP, accommodating a broad spectrum of organic compounds of various charge, implying potential transport interactions that can affect body distribution and organ clearance.

• 한국버섯학회지
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• 제14권1호
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• pp.1-5
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• 2016

이 연구는, 느타리버섯과 풀버섯만 재배하던 캄보디아에서 영지버섯, 목이버섯 그리고 표고버섯 등과 같은 여러 종류의 고온성 버섯들의 종균을 생산하고, 캄보디아에서 생산되는 경제적이고 효율적인 새로운 버섯배지를 찾기 위해 시도되었다. 종균 및 버섯재배 배지로, 여러 종류의 유기물찌꺼기, 곡물, 그리고 톱밥이 사용되었다. 고무나무 톱밥배지에서 자란 균사 (10.9 cm/15일)는 곡물배지에서 자란 균사 (11.2 cm/15일)에 비해 성장이 조금 느렸지만, 고무나무 톱밥은 낮은 가격 및 취급의 용이성이 있어, 비싼 곡물종균을 대치할 수 있는 매우 적절한 배지인 것으로 나타났다. 버섯생산을 위해서, 고무나무톱밥(60.8% BE), 사탕수수박(60% BE), 그리고 아카시아나무 톱밥 등에 미강과 탄산칼슘을 혼합하여 사용하였는데, 사탕수수박과 고무나무 톱밥은 매우 비슷한 높은 생물학적 효율(BE)을 보여주었고, 아카시아나무 톱밥은 비교적 낮은 22.4%의 생물학적 효율을 보여주었다. 따라서 낮은 가격에 구입할 수 있는 아카시아톱밥이 현재 사용되고 있는 높은 가격의 배지들과 혼합하여 사용된다면 매우 가능성이 높은 새로운 배지가 될 수 있을 것으로 보였다. 현재, 사용되고 있는 톱밥의 가격 (20 kg 고무나무톱밥=6500 Riel 혹은 1.6 USD)과 비교했을 때, 아카시아톱밥의 가격(20 kg=1000Riel 혹은 0.25USD)이 매우 낮아 버섯의 생산에 투자되는 비용을 크게 줄여 경제성을 높일 수 있을 것으로 사료된다.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.225-228
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• 2002

Amorphous $Ga_2O_3$ films have been grown on Si(100) substrates by metal organic chemical vapor deposition (MOCVD) using gallium isopropoxide, $Ga(O^iPr)_3$, as single precursor. Deposition was carried out in the substrate temperature range 400-800 $^{\circ}C$. X-ray photoelectron spectroscopy (XPS) analysis revealed deposition of stoichiometric $Ga_2O_3$ thin films at 500-600 $^{\circ}C$. XPS depth profiling by $Ar^+$ ion sputtering indicated that carbon contamination exists mostly in the surface region with less than 3.5% content in the film. Microscopic images of the films by scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed formation of grains of approximately 20-40 nm in size on the film surfaces. The root-mean-square surface roughness from an AFM image was ${\sim}10{\AA}$. The interfacial layer of the $Ga_2O_3$/Si was measured to be ${\sim}35{\AA}$ thick by cross-sectional transmission electron microscopy (TEM). From the analysis of gaseous products of the CVD reaction by gas chromatography-mass spectrometry (GC-MS), an effort was made to explain the CVD mechanism.

• 한국환경과학회지
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• 제25권8호
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• pp.1077-1085
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• 2016

The present study was investigated the effect of recycled coir organic substrates on the growth of different vegetable crops. The recycled coir had better physical and chemical properties than the new coir. The growth of tomato plant was better on the coir substrate that had been used for 2 years than that on the new coir substrate. The average number of tomato fruits was 108 on the new coir substrate, while it was 179 and 165 on the coir substrate used for 1 and 2 years, respectively. The growth of cherry tomato plant was also better on the coir substrate used for 2 years than that on the new coir substrate. The average number of cherry tomato fruits was 43 on the new coir substrate, while it was 206 and 164 on the coir substrate used for 1 and 2 years, respectively. The growth of brussel sprout was better on the coir substrate used for 3 years than that on the new coir substrate and the average number of brussel sprout leaves was 26.8 on the new coir substrate, while it was 34.3 on the coir substrate used for 3 years. The growth of Korean cabbage improved on the coir substrate used for 1 years compared to the new coir substrate and the number of leaves was 15.1 on the new coir substrate, while it was 24.3 on the coir substrate used for 1 year. Thus, used coir can be recycled to improve vegetable yields compared to using new coirs.

• 한국염색가공학회지
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• 제21권5호
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• pp.41-50
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• 2009

Design of experiments (DoE) concept was successfully applied to determine the optimum processing conditions that yield maximum % exhaustion for berberine interaction with synthetic tanning agent pretreated polyamide substrates. The potential of synthetic tanning agent to provide anionic sites on the polyamide for berberine interaction which is cationic in nature was tested to increase the % exhaustion of berberine in this article. Experiments were designed according to Central Composite Rotatable Design (CCRD). The three factors for synthetic tanning agent pretreatment and two factors for berberine interaction each at five different levels, including central and axial points were considered. Experiments were conducted in a laboratory scale infra-red treatment instrument according to CCRD. For each response, second order polynomial models were developed using multiple linear regression analysis incorporating linear, interactions and squared effects of all variables and then optimized. The significance of the mathematical model developed was ascertained using Excel regression (solver) analysis module. Analysis of variance (ANOVA) was performed to check the adequacy and accuracy of the fitted models. The response surfaces and contour maps showing the interaction of process variables were constructed. Applying Monte Carlo simulation, response surface and contour plots, optimum operating conditions were found and at this optimum point, % exhaustion of 81% and 74% respectively for synthetic tanning agent pretreatment and berberine interaction were observed and subsequently the results were experimentally investigated.

• Journal of Microbiology and Biotechnology
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• 제4권3호
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• pp.222-229
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• 1994

In order to develop a method of economical production and to reduce energy-consumption in fuel alcohol production, we investigated the fermentation characters of two newly selected thermotolerant yeasts. The RA-74-2 showed stable and superior fermentability between 30 and $40^{\circ}C$ in 20% glucose media in comparison to the industrial strains. The optimum concentration of glucose for economical fermentation at $40^{\circ}C$ was 15-18%, and organic nitrogen was necessary for a satisfactory fermentation. The optimum pH was 4.0 and aeration was adversed for high temperature fermentation. Agitation was an important factor at $40^{\circ}C$ and the addition of magnesium ion 0.2% was required in this experiment. When the inoculum was increased, ethanol productivity as well as the speed of fermentation increased. On the other hand RA-912, which can grow at $48^{\circ}C$, showed similar fermentability between 30-$45^{\circ}C$ in 20% glucose media As the concentration of substrate decreased, fermentation ratio increased at $45^{\circ}C$ (45%, 65%, 95% fermentation ratio in 20%, 15%, 10% glucose media, respectively). Also, requirement of organic nitrogen and magnesium ion in RA-912 was similar in RA-74-2. The optimum pH for fermentation was 5.0, and the effects of agitation were enhanced at $37^{\circ}C$ than at $45^{\circ}C$. As the inoculum was increased, fermentation speed became more enhanced but the ethanol productivity was less affected. RA-912 showed fermentability with various substrates. Among the substrates used, inulin was the most promising substrate for the high-temperature fermentation. When 14.5% inulin was used as the substrate, 93% and 55% fermentation ratios were shown at $37^{\circ}C$ and $45^{\circ}C$, respectively.

• 한국염색가공학회지
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• 제19권4호
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• pp.32-37
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• 2007

In this study, we have obtained the protein patterns using the membrane patterning of soft-lithography technique. The rapid detection of protein including bovine serum albumin (BSA) was resulted from the interaction with 1,3-bisdicyanovinylindane. For the proof of the interaction between BSA and dye, the UV-vis absorption spectra of BSA and dye were observed at 278 nm and 580 nm, respectively. As expected, the absorption spectrum of the interaction between BSA and dye was observed at 584nm. The absorption spectrum of the interaction was red-shifted. In addition, the optical images of the selectively reacted protein patterns showed the distinctive change of patterned color at different pH conditions. Because the dye has negative charges, the charge of BSA at different pH conditions could influence the interaction behavior between dye and BSA. Therefore, in the case of pH 7, the selectively patterned protein substrates obtained deep blue color pattern caused by electrostatic interaction between negative charges of the dye and positive charges of the BSA. However, in the case of pH 10, selectively patterned protein substrates obtained light blue color pattern because the electrostatic interaction was relatively lower than pH 7 due to the change of overall charge distribution of BSA.