• KSBB Journal
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• v.18 no.1
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• pp.74-77
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• 2003

A simple, reproducible, and rapid gas chromatographic method for putrefactive metabolite determination in feces was developed. The method involves the direct injection of fecal supernatants into the gas chromatograph, without pretreatment. The mass spectra of these metabolites were obtained using an HP 5971 mass selective detector operated in electron impact (EI) ionization mode. This method produced sharp peaks and allowed the simultaneous determination of fecal putrefactive metabolites.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.625-630
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• 2004

Granular media filtration is used almost universally as the last particle removal process in conventional water treatment plants. Therefore, superb particle removal efficiency is needed during this process to ensure a high quality of drinking water. However, every particle can not be removed during granular media filtration. Besides the pattern of particle attachment is different depending on physicochemical aspects of particles and suspension. Filtration experiments were performed in a laboratory-scale filter using spherical glass beads with a diameter of 0.55 mm as collectors. A single type of particle suspension (Min-U-Sil 5) and alum coagulation was used to destabilize particles. The operating conditions were similar to those of standard media filtration practice: a filtration velocity of 5 m/h. More favorable particles, i.e., particles with smaller surface charge, were well attached to the collectors especially during the early stage of filtration when zeta potential of particles and collectors are both negative. This selective attachment of the lower charged particles caused the zeta potential distribution (ZPD) of the effluent to move to a more negative range. On the other hand, the ZPDs of the effluent moved from more positive to less positive when the surface charge of particles was positive and this result was thought to be caused by ion transfer between particles and collectors.

• Journal of Environmental Health Sciences
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• v.18 no.2
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• pp.102-105
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• 1992

Introduction : Isothiazolinone product is one of new preservatives used in cooling tower, paper mill, and general industrial waters.l) It is also effective in controlling bacteria and fungi in the manufacture and storage of dispersed pigments, such as kaolin clays, titanium dioxide, calcium carbonate and others\ulcorner Its broad-spectrum activity, excellent physical and chemical compatibility with anionic, nonionic and cationic surfactants and most organic and inorganic compounds and low toxicity at recommended use levels provide formulators with an effective, economical, and environmentally acceptable alternative to other commercial biocides. It dose not contain or generate formaldehyde and is easy to formulate (1.5% solution is supplied as an aqueous solution), so that it gains advantage over the other preservatives. The active ingredients of the isothiazolinone product are unchlorinated compound (2-methyl-4-isothiazolin-3-one) and chlorinated one (5-chloro-2-methyl-4-isothiazolin-3-one). Methods preferred for the analysis of preservatives are chromatographic methods, especially high performance liquid chromatograph (HPLC). Although several methods were satisfactory in respect to separation, no offical method has been published for the isothiazolinone components. This study was performed to search for an alternative method in order to show flexible operating conditions of HPLC and to reduce assay time.

• Journal of the KSME
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• v.32 no.12
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• pp.1038-1048
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• 1992

오늘날 자동차에 요구되는 조건은 힘(출력), 안전성, 경제성(연비) 및 저 공해성이다. 아무리 힘이 좋고 안전하게 만들어졌다 하더라도 연료가 많이 소비되면 소비자들로부터 호감을 얻을 수 없 으며 공해를 많이 배출하게 되면 법에 의해 도로상을 주행할 수 없게 된다. 그러므로 오늘날 자동차 제작사는 저공해, 고연비자동차 개발에 온갖 힘을 쏟고 있다. 오늘날 자동차는 오염물질의 배출을 저감시키기 위하여 엔진개량, 연료개량 및 후처리기술을 적용하고 있지만 자동차의 급 격한 증가에 따라 연료소비량이 증가하고 아울러 오염물질의 배출량이 증가하여 대기를 오염시 킨다. 여기서는 자동차의 연료소비량을 감소시키기 위한 대책의 일환으로 실시하고 있는 정부 공인 표준연비에 대하여 알아보고 오염물질 배출량과의 관계 및 연비 향상대책에 대하여 고찰 해보고자 한다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.465-466
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• 2001

동물의 대사기능은 체내 주요 생리기능의 지표로서 체내의 물질대사 또는 에너지 대사의 결과를 반영한다 체내의 모든 생리적 과정은 동물과 환경간에 있어서 물질 및 에너지의 교환과 체내의 물질 및 에너지의 전환을 통해서 수행된다. 따라서 생체의 대사작용은 생존을 위한 역원적 중추기능이며 생체의 대사활성은 동물체의 기능적 항상성을 유지하는데 관련된 생리기능의 총체적 척도가 된다. (중략)

• The Korean Ginseng Research and Industry
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• v.1 no.1
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• pp.13-18
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• 2007

• Proceedings of the Petrological Society of Korea Conference
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• 2006.05a
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• pp.31-31
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• 2006

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.49-56
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• 2021

Liquefied Petroleum Gas is divided into liquefied gases containing propane (C₃H₈) and butane (C₄H₁₀). The quality of LPG varies greatly depending on the composition of the mixture, so it is important to measure the composition accurately. It is difficult to determine the composition of the mixture because liquid and gas coexist at room temperature. Therefore, the uncertainty in determining the concentration of hydrocarbons by component is high, and there are many problems that differ from the actual content standard. Therefore, it is necessary to develop a mixed liquid propane standard gas for the composition and accurate concentration of hydrocarbon substances. Mixed liquid propane standard gas is manufactured into bellows-type constant-pressure cylinders by ISO-6142 (2015). The homogeneity of the four standard gases manufactured was confirmed to be GC-FID. The manufacturer's uncertainty of expansion was 0.01 % to 0.30 % and homogeneity was 0.03 % to 0.25 %. In this mixed liquid propane standard gas, the relative expansion uncertainty of weight method, manufacturing consistency, cylinder adsorption and long-term stability was developed within 0.26 %-1.3 9% (95% of confidence level, k=2).

• Journal of Environmental Impact Assessment
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• v.25 no.6
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• pp.532-541
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• 2016

The National Environmental Specimen Bank (NESB) has been collecting broad leave samples to monitor environmental pollution from five different designated sampling areas. In order to ensure the reproducibility and comparability of the results, all the procedures from selecting trees and pooling leaves to make the representative sample are defined in the standard operation procedures(the SOP). The representative samples were subjected to the chemical analyses for some heavy minerals and Polycyclic Aromatic Hydrocarbons(PAHs). The uncertainty levels involved in each step of the SOP, that is, the sampling and the chemical analysis, were derived using the Robust ANOVA, which enables the relative comparison among the different levels of pollutants concentrations with confidence. Furthermore, the effect of the varying degrees of precipitation on the pollutants concentration of the leaves was also examined. Overall, the biological difference estimated from the duplicate samples was found to exceed the variation across the site, implying even aerial deposition over site. Samples from Gwanak Mt. showed highest heavy metal concentrations than the other sites. Washing off effect of the pollutants adhering in the form of particles on the leaf surface was found to be affected by the cumulative precipitation.

• Proceedings of the Korean Society for Quality Management Conference
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• 2004.04a
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• pp.127-132
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• 2004

기업에서 올바른 품질관리를 수행하기 위해서는 1차적으로 품질수준을 결정하는 각각의 요인들에 대한 정확한 데이터의 확보가 필요하며, 이를 위한 측정(measurement) 수단 또한 매우 중요하다고 할 수 있다. 올바른 측정을 위해서는 양호한 측정기기 뿐만 아니라, 이를 효과적으로 다룬 수 있는 측정인력의 존재 통은 필수적 요건이라 할 수 있다. 따라서 본 연구에서는 제품 생산의 불량률에 대한 추정방정식으로 많이 사용되는 로짓(logit) 모형을 이용하여 기업의 측정표준 관련 투자가 제품의 품질에 미치는 효과를 분석하였는데, 그 결과 측정 및 풀질관리 인력, 측정설비 구입비 및 표준실 운영비 통의 측정 관련 투자, 인증표준물질의 사용이 제품생산의 불량률 감소를 가져와 제품의 풀질에 효과를 미치는 것으로 나타났다. 또한 기업의 측정표준 투자 결정요인을 분석한 결과, 기업의 연구개발 투자가 많을수록, 시장에서의 독점력이 높을수록, 기업규모가 클수록, 피리고 재무구조가 탄탄할수록 측정표준 투자가 큰 것으로 나타났다.