• 대한미생물학회지
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• 제20권1호
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• pp.1-11
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• 1985

A total of 211 strains of Staphylococcus aureus which included 118 strains isolated from various clinical specimens of admitted patients of University Hospital with systemic or severe cases of infection and 93 strains from infected skin diseases of out-patients of dermatology clinic located in rural area, were tested for the antimicrobial susceptibility to the 12 drugs of common use and the phage typing. An these were subjected to the study of plasmid profile analysis for the molecular epidemiology of nosocomial infections. University Hospital(UH) isolates showed higher frequency of resistance than local clinic(LC) isolates against 10 drugs excluding tetracycline(Tc), and trimethoprim(Tp). The MIC of UH isolates were above than $128{\mu}g/ml$ against 9 drugs except Tc, gentamicin(Gm), and Tp, but LC isolates did not show such a high level of MIC. There was difference of MIC needed to inhibit 90% of strains(MIC90) against each drugs tested between two groups of UH and LC isolates. UH isolates showed 2 to 4 times higher value of MIC90 by two-fold serial dilution of drug concentration than LC isolates. Tp was considered as an effective drug in treatment of staphylococcal infections whereas ampicillin and Gm were appeared to be ineffective. Seventy-three strains(61.9%) of UH isolates and 70(69.9%) of LC were typable with phages from Colindale Reference Laboratory. The prevailing phage type of UH isolates belonged to lytic group II were 27 strains(22.9%) and those of LC isolates belonged to lytic group II were 23 strains(24.7%). Thirteen strains(11.0%) of UH isolates were multiply resistant to more than 5 drugs to 10 drugs but none of LC isolates. Through the lysis method of Kado and Liu followed by agarose gel electrophoresis, none of 211 strains showed plasmid profile. These results were confirmed by re-examination through the method of Birnboim and Doly.

• 대한임상검사과학회지
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• 제37권1호
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• pp.22-26
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• 2005

Total homocysteine is now considered a risk factor for cardiovascular diseases. I increased interest has led to a multitude of studies requiring the determination of total homocysteine in conjunction with other factor. There are various methods for measuring total homocysteine, including HPLC, FPIA, GC-MS and LC-MS/MS. The most recent method for measuring total homocysteine uses a deuterium-labelled internal standard and tandem mass spectrometry. This development requires no derivatization and therefore leads to an increase in sample throughput compared to other techniques. We have evaluated the method for homocysteine by the LC-MS/MS method, and the correlation between the FPIA method and the LC-MS/MS method. The standard curve (0, 5, 10, 20, 50, 100 uM) was linear over the range examined (up to 100 uM). The lower limit of quantification (CV < 10 %) was 0.5 uM/L and the lower limit of detection (S/N >3) was 0.1 uM/L. Intra-assay variation and inter-assay variation were both <6 %. The comparision study for homocysteine concentration showed good correlation (r=0.9684) between the FPIA method and LC-MS/MS methods. Our conclusion is that the method showed relatively good precision, and was rapid and accurate.

• 한국전기전자재료학회논문지
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• 제28권7호
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• pp.439-445
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• 2015

We established the emulsion method using membrane filter with precise control of LC droplet distribution in PDLC. PDLC cells with various LC droplet size distributions such as single droplet sizes of $1.0{\mu}m$, $1.9{\mu}m$ and $3.5{\mu}m$, the mixture of two different LC droplet sizes and the mixture of three different LC droplet sizes were fabricated and the electro-optical properties of the emulsion type PDLC cells with various droplet size distribution were investigated. In the appropriate droplet size range, the PDLCs with the single droplet sizes distributions have good electro optical properties than those with the mixture of three different LC droplet sizes. In addition, the PDLC cells with the mixture of two different LC droplet sizes have the better electro optical properties than those with single droplet sizes distribution. The PDLC cell with dual droplet size distribution of $1.0+1.9{\mu}m$ shown the best electro optical properties than the PDLC cells with other size distributions. This method enabled us to find the proper LC droplet size distribution for achieving both high transmittance and contrast ratio.

• 한국환경보건학회지
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• 제21권2호
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• pp.27-35
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• 1995

In order to investigate acute toxicity and bioconcentration of heavy metals for a freshwater fish, the fish used in this experiment was goldfish, Carassius auratus. Each ten goldfish was accommonidated in a water and was treated with different concentration of Pb and Cu compound. The 24 $hr-LC_{50}$ was obtained by plotting on the log-normal distribution graph. Furthermore, the combined effect of Pb and Cu was also investigated the fish was treated with Pb or Cu compound only, and Pb and Cu compound together, respectively. These results were summarized as follows: 1. The 24 $hr-LC_{50}'s$ of Pb and Cu were 7.48 mg/l and 0.666 mg/l, respectively. 2. When single or/and combined treatment with Pb(7.0 mg/l) or/and Cu(0.6 mg/l) to Carassius auratus for 24 hours were performed, there was significant difference between the single or/and the combined treatment in their bioaccumulated Cu concentrations. Cu concentrations in goldfish were higher in the combined treatment than in the single treatment. 3. When Carassius auratus was exposed to 0.748 mg/l (1/10 of 24 $hr-LC_{50}$) and 1.496 mg/l of Pb (1/5 of 24 $hr-LC_{50}$) for 7 days, the bioconcentration factors (BCF) were 79.14 and 100.11 for Pb, respectively. The BCF of Pb was obtained as a linearity according to the concentration and exposure time as follows log BCF=1.014 log $P\cdot T$+1.011 ($r^2$=0.9041) where, P: pollutant concentration(mg/l) T: exposure time(day) 4. When Carassius auratus was pxposed to 0.0666 mg/l (1/10 of 24 $hr-LC_{50}$) and 0.1332 mg/l of Cu (1/5 of 24 $hr-LC_{50}$) for 7 days, the bioconcentration factors (BCF) were 55.42 and 63.24 for Cu respectively. The BCF of Cu was obtained as a linearity according to the concentration and exposure time as follows log BCF=0.571 log $P\cdot T$+1.823 ($r^2$=0.8974) where, P: polutant concentration(mg/l) T: exposure time(day)

• 분석과학
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• 제25권6호
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• pp.435-440
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• 2012

지표수 중에 과염소산이온을 LC-ESI-MS/MS을 사용하여 분석하였다. 시료는 단지 PTFE 필터를 사용하여 거른 후 LC-ESI-MS/MS 시스템에 직접 주입하여 분석하였다. 이 방법은 3% 이내의 정밀도를 보였고 정량한계는 0.17 ${\mu}g/L$이었다. 시료는 금강물 35 개 유역에서 2, 4, 6월에 각각 시료를 채취하였다. 그 결과 일반 하천수에서는 과염소산이온이 0.23-3.73 ${\mu}g/L$ (평균 0.20 ${\mu}g/L$) 농도범위로 15% 빈도로 검출되었고 공단 근처의 지표수에서는 0.36-25.10 ${\mu}g/L$ (평균 1.69 ${\mu}g/L$)로 36%의 빈도로 검출되었다.

• 한국토양비료학회지
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• 제45권1호
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• pp.86-92
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• 2012

To promote the practical use of livestock manure compost (LC) for paddy rice cultivation, the fertilization efficiency of nutrients in LCs was investigated compared to that of chemical fertilizer. This experiment was conducted at rice field in Hwaseong, Korea, with 6 treatments by each of 3 kinds of tested LCs, cattle manure compost (CaC), swine manure compost (SwC) and chicken manure compost (ChC). The treatments consisted of 3 application levels of LCs and 3 chemical fertilizer treatments having the same application levels with LCs. $NH_4$-N content in soil became higher according to the increase in the urea application rate, while it became lower in LC plots than in urea plots, and statistically had no significant difference among LC plots. There was a close relationship between phosphate fertilization rate and the increment of soil available phosphate content after experiment resulting y = 0.1788x - 6.169 ($R^2=0.9425$) when applied fused superphosphate fertilizer, and y = 0.0662x - 2.689 ($R^2=0.9315$) when applied LC at the equivalent rates to phosphate input (x: phosphate application rate, kg $ha^{-1}$, y: increment in soil available phosphate content, mg $kg^{-1}$). And from these two equations, the correlation on the phosphate application rate between fused superphosphate fertilizer and LC could be obtained as y = 2.7056x - 52.492 (x: $P_2O_5$ application rate of fused superphosphate, kg $ha^{-1}$, y: $P_2O_5$ application rate of LC, kg $ha^{-1}$). Plant height, number of tillers, nutrients uptake by rice, and rice yield showed higher levels in N 100% and N 150% application plots of chemical fertilizers, while every LC plots exhibited lower values and no significant difference among them. Relative nitrogen fertilization efficiencies of LCs compared to urea was 12.3% for CaC, 8.8 for SwC and 24.6 for ChC, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 및 기술 세미나 논문집 디스플레이 광소자
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• pp.42-42
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• 2008

Considerable attention has been focused on the applications of flexible liquid crystal (LC)-based displays because of their many potential advantages, such as portability, durability, light weight, thin packaging, flexibility, and low power consumption. To develop flexible LCDs that are capable of delivering high-quality moving images, like conventional glass-substrate LCDs, the LC device structure must have a stable alignment layer of LC molecules, concurrently support uniform cell gaps, and tightly bind two flexible substrates under external tension. However, stable LC molecular alignment has not been achieved because of the layerless LC alignment, and consequently high-quality images cannot be guaranteed. To solve these critical problems, we have proposed a PDMS pixel-wall based bonding method via the IB irradiation was developed for fasten the two substrates together strongly and maintain uniform cell gaps. The effect of the IB irradiation on PDMS with PI surface was also evaluated by side structure configuration and a result of x-ray photoelectron spectroscopic analysis of PDMS interlayer as a function of binder with substrates. large number of PDMS pixel-walls are tightly fastened to the surface of each flexible substrate and could maintain a constant cell gap between the LC molecules without using any other epoxy or polymer. To enhance the electro-optical performance of the LC device, we applied an alignment method that creates pretilt angle on the PI surface via ion beam irradiation. Using this approach, our flexible LCDs have a contrast ratio of 132:1 and a response time of about 15 ms, resulting in highly reliable electro-optical performance in the bent state, comparable to that of glass-substrate LCDs.

• 대기
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• 제21권4호
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• pp.415-427
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• 2011

In this study, the impacts of land surface conditions, land cover (LC) map and leaf area index (LAI), on the short-range weather forecast over the East-Asian region were examined using Unified Model (UM) coupled with the MOSES 2.2 (Met-Office Surface Exchange Scheme). Four types of experiments were performed at 12-km horizontal resolution with 38 vertical layers for two months, July and August 2009 through consecutive reruns of 72-hour every 12 hours, 00 and 12 UTC. The control experiment (CTRL) uses the original IGBP (International Geosphere-Biosphere Programme) LC map and old MODIS (MODerate resolution Imaging Spectroradiometer) LAI, the new LAI experiment (NLAI) uses improved monthly MODIS LAI. The new LC experiment (NLCE) uses KLC_v2 (Kongju National Univ. land cover), and the new land surface experiment (NLSE) uses KLC_v2 and new LAI. The reduced albedo and increased roughness length over southern part of China caused by the increased broadleaf fraction resulted in increase of land surface temperature (LST), air temperature, and sensible heat flux (SHF). Whereas, the LST and SHF over south-eastern part of Russia is decreased by the decreased needleleaf fraction and increased albedo. The changed wind speed induced by the LC and LAI changes also contribute the LST distribution through the change of vertical mixing and advection. The improvement of LC and LAI data clearly reduced the systematic underestimation of air temperature over South Korea. Whereas, the impacts of LC and LAI conditions on the simulation skills of precipitation are not systematic. In general, the impacts of LC changes on the short range forecast are more significant than that of LAI changes.

• 대한환경공학회지
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• 제30권1호
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• pp.37-44
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• 2008

본 연구에서는 퍼클로레이트 분석에 주로 사용되고 있는 IC와 LC/MS를 사용해 퍼클로레이트 분석법을 정립하고 각 분석법의 장단점 및 효율을 파악해 수질 및 토양 시료에서의 퍼클로레이트를 모니터링 하고자 하였다. 각 분석기기를 사용한 최적분석 방법을 정립한 결과 IC에서의 MDL은 1 ppb였으며 LC-MS에서의 MDL은 0.005 ppb였다. 정립된 분석방법으로 부산시 내의 지하수 및 약수터, 하수처리장과 토양 시료를 대상으로 하여 퍼클로레이트 모니터링을 실시하여 퍼클로레이트에 대한 노출정도를 평가하였다. 평균 퍼클로레이트 농도는 약수터에서는 0.013 $\pm$ 0.014 ppb, 지하수 0.031 $\pm$ 0.011 ppb로 나타났고 하수처리장 폐수에서는 0.007$\sim$0.380 ppb의 범위로 퍼클로레이트가 검출되었다. 모든 시료에서의 퍼클로레이트 농도는 EPA 기준인 24.5 ppb 이하로 나타났다.

• Nuclear Engineering and Technology
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• 제20권3호
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• pp.179-188
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• 1988

최근 개발된 유한차분법의 하나인 선형특성 (LC) 법을 절단오차의 분석을 통하여 계단형 차분 (SD)법, 다이아몬드형차분 (DD)법, 그리고 계단형특성 (SC) 법과 비교했다. 제시된 4가지 방법들이 선속 계산문제, 유효증배계수 계산문제, 그리고 임계평판 두께 계산문제에 적용되었으며, 그때 계산된 결과들은 몇몇의 절단오차 측정 기준들에 의해 평가되어졌다. 본 연구의 주요 결론으로, 모든 경우에 있어서 어느 정도 기대했던 바와 같이 선형특성법이 가장 우수하다는 것이 밝혀졌으며, 특히, 선형특성법은 유효증배계수와 임계평판두께 같은 적분 인자들을 정확하게 계산하는데, 이는 선형특성법이 다른 방법들에 비해 오차소거(Error Cancellation)작용이 효과적으로 일어나기 때문으로 밝혀졌다.