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        검색결과 4

        1.
        2007.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Information about the chemical components emitted from the household products employed in many other countries seems to be still relatively scant and insufficient. The emissions composition for 59 consumer products were evaluated using a headspace analysis. The chemical composition and concentrations of total voalatile organic compounds (VOCs) broadly varied along with products. No volatile pollutants were detected for only one product in the household product category of laundry detergents. Except for this product, 1 to 17 organic compounds were detected in the headspace gas phase of each product. The category of oil paints exhibited an upper range for both the number of chemicals detected and the concentrations of total VOC. The chemical composition of certain household products determined in the current study was different from that for other studies from other countries. Four to 37 compounds were detected in the headspace gas phase of each product class. Several compounds were identified in more than one product class. Although several results indicated the dependence of the headspace temperature or period on the proportions of constituents in headspace gas phase, the effect of the headspace conditions on headspace concentrations varied along with the type of household product or analyte. It is suggested that a proper headspace conditions should be considered based on the volatility of components and matrix of each household product as well as the analytical sensitivity.
        4,200원
        2.
        2023.02 KCI 등재 서비스 종료(열람 제한)
        Filter and microbalance sensitivity in measuring fine particulate matter mass is greatly influenced by particulate properties and environmental factors. Temperature and humidity control inside a measuring chamber with a microbalance, and neutralization of static charges on filters are essential for consistent filter weighing. Commercial weighing chambers are expensive with a unit price of tens of millions won. This study developed an inexpensive weighing chamber for weighing fine particulate matter and evaluatedits weighing performance. A microbalance with 1 μg precision was used to measure the weight of a filter. The microbalance was set in a transparent acrylic enclosure (100 x 60 x 65 cm3) equipped with temperature and humidity control equipments. Weighing performance of the chamber was examined using Teflon filters with or without different particulate sample types. Temperature and humidity were maintained at approximately 23.2±1.2 ℃ and 36.2±1.8℃ for 8 days, respectively.
        3.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        Oxidative and thermal degradation of alkanolamines for a promising CO2 capture technology of absorption might cause decrease in CO2 capture efficiency and formation of hazardous byproducts. In this study, characteristics of a representative absorbent of monoehtanolamine (MEA) were examined for a long term operation using a laboratory scale absorption system. An CO2 absorption system with ID 56 mm and absorption zone height 100 cm was developed for the characterization. Absorption solution of 30 wt% MEA was circulated at 100 mL/min to treat air with 15% CO2 and 1 ppm NO at 10 L/min. Temperatures of absorber and stripper were maintained at 40℃ and 120℃, respectively. For the course of 5 weeks continuous operation, MEA concentration was decreased approximately by 70% and CO2 removal efficiency was dropped from 95% to 65%. Ionic byproducts of NH4 +, NO2 -, and NO3 - were accumulated up to 48 g/mL, 0.2 g/mL, and 1.5 g/mL, respectively, tracking the variation of MEA concentration. Formation of various organic byproducts were also observed.
        4.
        2012.01 KCI 등재 서비스 종료(열람 제한)
        A thermal-optical transmittance carbon analyzer has been developed to determine particulate organic (OC) and elemental (EC) carbon. Several analysis factors affecting the sensitivity of OC and EC determination were investigated for the carbon analyzer. Although total carbon (TC) is usually consistent in the determination, OC and EC split is sensitive to adopted analysis protocol. In this study the maximum temperature in oxygen-free He in the analysis was examined as a main cause of the uncertainty. Prior to the sensitivity analysis consistency in OC-EC determination of the carbon analyzer and the uniformity of carbonaceous aerosol loading on a sampled filter were checked to be in acceptable range. EC/TC ratios were slightly decreased with increasing the maximum temperature between 550-800oC. For the increase of maximum temperature from 500oC to 800oC, the EC/TC ratio was lowered by 4.65-5.61% for TC loading of 13-44 μg/cm2 with more decrease at higher loading. OC and EC determination was not influenced by trace amount of oxygen in pure He (>99.999%), which is typically used in OC and EC analysis. The facing of sample loaded surface to incident laser beam showed negligible influence in the OC-EC split, but it caused elevated PC fraction in OC for forward facing relative to backward facing.