• Korean Journal of Clinical Laboratory Science
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• v.53 no.2
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• pp.143-150
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• 2021

The recent spread of novel and highly variant pathogenic viruses, including the coronavirus (SARS-CoV-2), has increased the demand for diagnostic testing for rapid confirmation. This has resulted in investigating the functional capability of each space, and preparing facility guidelines to secure the safety of medical technologists. During viral evaluations, there is a requirement of negative pressure facilities along with thread separation, during pre-treatment of samples and before nucleic acid amplification. Space composition therefore needs to be planned by considering unidirectional air flow. This classification of safety management facilities is designated as biosafety level 2, and personal protective equipment is placed accordingly. In case of handling dangerous materials, they need to be carried out of the biosafety cabinet, and sterilizers are required for suitable disposal of infectious agents. A common feature of domestic laboratories is maintenance of the sample pre-treatment space at a negative pressure of -2.5 Pa or less, and arranging separate pre-treatment and reagent preparation spaces during the test process. We believe that the data generated in this study is meaningful, and offers an efficient direction and detailed flow for separation of the inspection process and space functions. Moreover, this study introduces construction of the laboratory by applying the safety management standards.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.22-30
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• 2015

So far, most of research activities on modeling of membrane separation processes have been focused on binary feed mixture. But, in actual separation operations, binary feed is hard to find and most separation processes involve multicomponent feed mixture. In this work models for membrane separation processes treating multicomponent feed mixture are developed. Various model types are investigated and validity of proposed models are analysed based on experimental data obtained using hollowfiber membranes. The proposed separation models show quick convergence and exhibit good tracking performance.

• The Korean Journal of Financial Management
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• v.26 no.3
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• pp.31-64
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• 2009

This article investigates the short-term cash flow exposures to Korea's major trading partners' currencies based on the kospi and kosdaq firm data from 2000 to 2008. The cash flow approach allows us to analyze the influence on operational performances of individual firm's hedging strategies. Taken all three foreign exchange rates together, more than 30% of the sample firms exhibit significant exposure. Given that the short-term cash flow is rather easy to hedge, the result proves a poor exchange rate risk management practices of Korean firms. Kosdaq firms are more exposed than Kospi firms. On the contrary to the previous researches using stock prices, the operational cash flows show a positive relationship with the value of foreign currencies. The exchange rate-firm sample further shows that the size and leverage affect the level of exposure.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.232-235
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• 2000

본 논문에서는 ITS(Intelligent Transport System) 서비스를 위한 기반시설로 설치 예상되는 DSRC(Dedicated Short Range Communication) 시스템에 대하여 시스템의 개요와 특징 및 DSRC 기지국시스템의 신호흐름에 대하여 살펴보았으며, 일체형과 분리형 DSRC 시스템의 RSU구조에 관해 비교 분석하였다.

• The Korean Publising Journal, Monthly
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• s.83
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• pp.15-15
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• 1991

구비전승되는 민속문화의 한갈래인 설화를 새로운 방법론으로 탐구한 것과 10여년간 우리 전통문화의 세계를 탐구해오며 발표했던 글들을 묶은 평론집으로 구별되는 이번 두 저술에서 저자는 민속학의 연구가 역사의 흐름과 사회적 실천에서 결코 분리되어 있어서는 안됨을 강조하고 있다.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1991.07a
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• pp.64-68
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• 1991

Heaps(1972)가 수직좌표계 처리에서 Spectral expansion 기법을 사용하는 3차원 수치모델을 적용한 이래 조류, 풍성류, 밀도류 등 천해역의 흐름현상에 대해 스펙트랄 모델을 적용하여 현상을 재현, 예측하는 연구가 활발히 전개되어 왔다.(중략)

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.241-249
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• 2012

This paper presents the lateral displacement of a particle passing over a planar interdigitated electrode array at an angle as a function of particle size. The lateral displacement was also measured as a function of the angle between the electrode and the direction of flow. A simplified line charge model was used for numerical estimation of the lateral displacement of fluorescent polystyrene (PS) beads with three different diameters. Using the lateral displacement as a function of particle size, we developed a lateral dielectrophoretic (DEP) microseparator, which enables the continuous discrimination of particles by size. The experiment using an admixture of 3-, 5-, and $10-{\mu}m$ PS beads showed that the lateral DEP microseparator could continuously separate out 99.86% of the $3-{\mu}m$ beads, 98.82% of the $5-{\mu}m$ beads, and 99.69% of the $10-{\mu}m$ beads. The lateral DEP microseparator is thus a practical device for the simultaneous separation of particles according to size from a heterogeneous admixture.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.19 no.1
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• pp.20-30
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• 1993

Liquid Chromatographic behavior of Pd(II) in Isonitosoethylacetoacetate imine IEAA-NR: R=H, CH3, C2H5, n-C3H7, n-C4H9, C6H5-CH2) Chelates were investigated by reversed phase high performance 1iquid chromatography on Micropak MCH-5 Column using Methanol /water as mobile phase. The optimum condition for the separation of Pd-Isonitrosoethylacetoacetate imine chelates were examined with respect to the flow rate, mobile phase strength. It was found that Pd(IEAA-NR)2 chelates were eluted in an acceptable range of the capacity factor value (0 $\leq$ log k' $\leq$ 1), The dependence of the logarithm of capacity factor(k') on the volume fraction of water in mixture with in the binary mobile phase was examined. Also, the dependence of k'on the liquid-liquid extraction distribution constant in methanol-water / n-alkane extraction system was on system was invert tigated for Pd(IEAA-NR)2. Both kinds of dependence are linear, which suggests that the retention of the electroneutral metal chelates be largely due to the solvophobic effect.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.678-682
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• 2009

하천의 합류부에서는 홍수시 침수피해가 빈번하게 발생 하거나 하안침식, 강턱붕괴, 하천의 장갑화 등의 악영향이 발생하는데, 이러한 현상의 원인 규명을 위해 본류와 지류의 유량비에 의해 혹은 지류의 유입각에 의해 다양한 흐름 특성을 가정하고 개수로 장치를 이용하거나 수치모형 실험을 통하여 연구되고 있다. 본 연구에서는 미시시피 대학 연구기관인 NCCHE(Natioanl Center for Computational Hydroscience an Engineering)에서 개발한 CCHE2D 2차원 수치모형을 이용하여, 개수로 합류부에서 흐름 및 하상변동 특성을 분석하였다. 수치모의 결과는 "Experiments on Flow at a $90^{\circ}$ Open-Channel Junction", Journal of Hydraulic Engineering, May 2001, Vol. 127, No. 5, 340-350.에 기재되었던 논문의 실내실험 결과와 비교분석하였으며, 유속의 분포는 $0.01{\sim}1.0$ m정도로 개수로 관측치와 비교적 유사하게 모의 되었다. 또한 하상 변동 모의 결과 Biron 등(1996)이 제안한 합류부에서 6구역의 흐름 정의도와 대체적으로 유사하게 모의 되었으며, 최대 유속 구간에서 $-0.2m{\sim}0.03m$의 침식이 발생하고, 정체 구간과 분리구간에서 $0.01{\sim}0.02m$의 퇴적이 발생하였다. 본 연구의 결과는 하천의 물리적 특성을 파악하고 하천공사나 수리구조물 설계의 기초 자료로 활용될 수 있을 것으로 판단된다.

• Analytical Science and Technology
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• v.25 no.6
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• pp.476-482
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• 2012

Asian dust particles are known to have sizes ranging from a few nanometers up to about a few micrometers. The environmental and health effects depend on the size of the dust particles. The smaller, the farther they are transported, and the deeper they penetrate into the human respiratory system. Sedimentation field-flow fractionation (SdFFF) provides separation of nano to microparticles using a combination of centrifugal force and parabolic laminar flow in a channel. In this study, the steric mode of SdFFF (Sd/StFFF) was tested for size-based separation and characterization of Asian dust particles. Various SdFFF experimental parameters including flow rate, stop-flow time and field strength of the centrifugal field were optimized for the size analysis of Asian dust. The Sd/StFFF calibration curve showed a good linearity with $R^2$ value of 0.9983, and results showed an excellent capability of Sd/StFFF for a size-based separation of micron-sized particles.The optical microscopy (OM) was also used to study the size and the shape of the dust particles. The size distributions of the samples collected during a thick dust period were shifted towards larger sizes than those of the samples collected during thin dust periods. It was also observed that size distribution of the sample collected during dry period shifts further towards larger sizes than that of the samples collected during raining period, suggesting the sizes of the dust particle decrease during raining periods as the components adsorbed on the surface of the dust particles were removed by the rain water. Results show Sd/StFFFis a useful tool for size characterization of environmental particles such as the Asian dust.