• 한국환경과학회지
• /
• 제11권4호
• /
• pp.383-389
• /
• 2002

Odor sources of a chemical plant in Ulsan were surveyed and temperatures, humidities and flow rates of each exhaust gas were measured. The air samples collected from each source were transferred to the laboratory for sensory test and their odor concentrations were investigated. The odor emission rate of each source was estimated from the recorded results and assigned the sources expected to be needed for the odor prevention policy using the simple prediction equation of the affection by malodor to the nearest residential area. From the total odor emission rate of the examined plant and the relation table for expectable affection area it was concluded that total odor emission of this plant might be decreased for the prevention of residential complaint.

• 천문학회보
• /
• 제40권1호
• /
• pp.67.3-67.3
• /
• 2015

We present the high-resolution Immersion GRating INfrared Spectrograph (IGRINS) spectra of two Class I sources, IRAS03445+3242 and IRAS04239+2436. Both sources show the evidence of Keplerian disks; the broadened CO overtone (${\Delta}v=2$) transitions in emission and neutral metal lines (Mg I, Fe I, and Al I) in absorption. The thin Keplerian disk with a rotational velocity of ~100 km s-1 and a gas temperature of 5000 K at the innermost annulus can reproduce the CO overtone transitions including the bandhead emission. The outer dusty disk or the envelope needs to fit the narrow absorption features overlaid on the broad emission lines in the CO overtone transitions.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
• /
• pp.60-63
• /
• 2001

Investigating electromagnetic emissions of inverter power sources for resistance welding existing special aspects of EMI measurements in the field of resistance welding machines resulting from the power rating and intermittent operation mode of these machines have to be taken into account. The characteristics of the internal switching processes determined by the behavior of the applied power semiconductors, snubber circuits and constructional aspects exert a great influence on the conducted emission of resistance welding inverters.

• 천문학회보
• /
• 제37권2호
• /
• pp.140.1-140.1
• /
• 2012

We investigate properties of maser emission for 3373 O-rich AGB stars. We divide the sample stars into four different groups whether they were detected by OH, SiO and $H_2O$ maser emission or not. To understand the nature of the maser sources, we present various infrared two-color diagrams (2CDs) using IRAS, near infrared and AKARI data. For each group, we compare the positions on the various infrared 2CDs with theoretical models. We find that OH maser sources generally show higher color indices and larger dust optical depths than SiO or $H_2O$ maser sources. This could be due to differences of the mass-loss rates and/or variability which may influence the maser pumping mechanisms.

• Journal of Information Display
• /
• 제6권4호
• /
• pp.35-39
• /
• 2005

In this paper, we investigate the oxide cathodes for the development of reliable electron sources. Poisoning in oxide cathodes is one of the serious problems in achieving reliable electron emission. In particular, early poisoning induces poor life performance as will be demonstrated herein. The survivability of electron emission sources is significantly improved by high doping of high-speed activator. The robust oxide cathodes with 0.17 % Mg operating at about 1,050 K are expected to work for very long times (>100,000 hours). We suggest that this key idea will contribute to solving the basic problems in oxide cathodes such as poisoning or ion bombardment for high power or high frequency applications of electron sources.

• 한국재난관리표준학회지
• /
• 제2권1호
• /
• pp.65-74
• /
• 2009

환경재해방지와 대기오염관리를 목적으로 GIS기반의 대기 오염관리시스템 즉 높은 시 공간적 해상도의 오염물질배출량 산정과 영향예측, 자료관리 및 분석 등이 가능한 지리정보시스템을 구성하였다. 사례연구는 다양한 오염원의 존재하여 대기오염물질 배출량 증가로 인하여 환경재해의 가능성이 상존하는 광양만지역을 선정하고, 대기오염관리시스템에 오염원의 속성 공간자료체계를 구축과 배출모형, 대기오염모델, 분석도구 등을 이용하여 배출량 산정과 영향예측, 분석 등을 수행하였다. 분석결과, 산정된 배출량이 대상지역 오염원의 위치와 오염물질의 배출특성, 공간분포와 일치하는 정확한 예측결과를 나타내었다. 또한, 대기 오염모델의 TSP 예측결과는 실측값과 상관계수가 0.75로서 다소 높은 상관도와 오염원 영향농도와 범위 등의 파악에서 명확한 분석기능이 제공되는 것으로 나타났다, 본 연구에서 개발된 대기 오염관리시스템은 신속한 공간 속성 자료체계(database)의 구축과 높은 시 공간적 해상도의 배출량 산정, 대기오염모델의 입력자료 생성, 영향예측, 다양한 결과분석 등이 가능하여 합리적인 대기오염관리의 분석도구로서 사용될 수 있을 것으로 사료된다.

• Journal of Korean Society for Atmospheric Environment
• /
• 제15권E호
• /
• pp.29-38
• /
• 1999

This study identified emission sources and emissions of air pollutants such as volatile organic compounds (VOCs), solvents, and acid gases produced from chemical plants. We collected air samples from various processes, reactors and facilities using VOC detectors and workers' experience. We identified chemical structures and emission concentrations of air pollutants. We analyzed total emissions of air pollutants emitted from the chemical plants. Also, we developed some emission reduction technologies based on chemical types and emission situations of the identified air pollutants. For reduction of air emissions of acid gases, we employed a method improving solubility of pollutants by reducing scrubber operation temperature, increasing surface area for effective contact of gas and liquid, and modifying or changing chemicals used in the acid scrubbers. In order to reduce air emissions of both amines and acid gases, which have had different emission sources each other but treated by one scrubber, we first could separate gas components. And then different control techniques based on components of pollutants were applied to the emission sources. That is, we first applied condensation and then acid scrubbing method using H2SO4 solution for amine treatment. However, we only used an acid scrubbing method using H2O and NaOH solution for acid gas treatment. In order to reduce air emissions of solvents such as dimethylformamide and toluene, we applied condensation and activated carbon adsorption. In order to reduce air emissions of mixture gases containing acid gases and slovents, which could not be separated in the processes, we employed a combination of various air pollution control devices. That is, the mixture gases were passed into the first condenser, the acid scrubber, the second condenser, and the activated carbon adsorption tower in sequence. In addition, for improvement of condensation efficiency of VOCs, we changed the type of the condensers attached in the reactors as a control device modification. Finally, we could successfully reduce air emissions of pollutants produced from various chenmical processes or facilities by use of proper control methods according to the types and specific emission situations of pollutants.

• 한국대기환경학회지
• /
• 제32권2호
• /
• pp.193-207
• /
• 2016

This study discusses the present status of mercury emission and distribution from major anthropogenic sources in Korea and the future trend of mercury emission by activity changes and application of BATs. Atmospheric mercury emission from major anthropogenic sources based on Annex D of Minamata convention was estimated to around 4.89 tonne in 2012. Emission ratios of cement clinker production, coal-fired power plant, waste incineration and non-ferrous metal smelting were 68.68%, 24.75%, 6.29% and 0.28%, respectively. High mercury emission regions were characterized by the presence of cement clinker production facilities and coal-fired power plants. Prediction of future activities was carried out by linear regression of the previous year data. The (total) mercury emission was estimated to decrease up to 48% Under the scenario of BATs to be applied and the change of future activities. Emissions from coal-fired powerplants and cement clinkers were expected to decrease significantly.

• 천문학논총
• /
• 제32권1호
• /
• pp.281-285
• /
• 2017

We present a summary of our spectroscopic redshift catalogue of 404 sources in the AKARI Deep Field South (ADF-S). We have used the AAOmega spectrograph to target mid-infrared and far-infrared sources selected primarily from AKARI observations in this field for which we were able to obtain optical counterparts. Our sources with identified redshifts include 316 with $H{\alpha}$ detections at $z{\leq}0.345$ and 15 sources at z > 1 with MgII or $Ly{\alpha}$ emission lines. About 13% of our $z{\leq}0.345$ sources are dominated by active galactic nuclei (AGN) emission, although many show emission from both star formation and AGNs. The median Balmer decrement is 5.9. Ultra-luminous infrared galaxies (ULIRGs) were found only in the higher-redshift sources. Optical and near infrared data will be available shortly, enabling calibration of the line luminosities and spectral energy distribution (SED) fitting for these sources.

• 한국대기환경학회지
• /
• 제25권2호
• /
• pp.99-107
• /
• 2009

This paper reviews the current status of mercury research on exposure and contamination, mercury emissions, emission limits and control technologies, long-range transport and deposition research, and mercury management policy in Korea. According to a monitoring of the Ministry of Environment and the Ministry of Health and Welfare, blood mercury levels among Koreans are $5{\sim}8$ times higher than those of U.S. and Germany. The most dominant source of exposure to mercury is through dietary intake. Emissions of mercury from coal-fired power plants are estimated 8.93 ton/year in 2004. Emissions of mercury from other important sources, such as waste incineration, steel and cement manufacturing and non-ferrous metal smelting operations are to be further investigated. A study on long-range transport of mercury suggests that the dry deposition flux over the Yellow Sea was much greater than those for other oceans. As a whole, the amounts of wet depositions of nitrogen and sulfur were 1.9 and 1.5 times larger than the amounts of dry depositions in each species, respectively. Substantial influence from China caused by high emissions in East China and westerly wind was possibly suggested. However, the influence from nitrogen emission in Korea was also confirmed. Korean Government has already adopted stringent emission limits on mercury for incinerators and boilers in 2005. However, emission limits for coal-fired power plants and non-ferrous metal smelters are rather relaxed. As the above mentioned two sources can be two most important sources of mercury emissions, control strategy for those sources are to be considered.