• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.73-76
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• 2003

SF$_{6}$ (Sulfur Hexafluoride) is a gaseous compound whose use is being greatly increased recently. The compound has a negligible background concentration from natural sources and is stable in most of groundwater environments. Therefore, SF$_{6}$ has potential for a dating tool for young groundwater. It has many advantages over chlorofluorocarbons (CFCs) for groundwater investigation that sampling procedure is much simpler than CFCs and its growth is continued up to at least near future in the atmosphere. However, solubility of SF$^{6}$ is so low that excess air causes large uncertainties in recharge date of groundwater. To compensate the limitation, $N_2$/Ar method can be employed to estimate excess air content. A groundwater study is currently carrying out in Jeju Island using SF$_{6}$ as an environmental tracer, Well waters and spring waters were sampled for SF$_{6}$ and $N_2$/Ar. To establish SF$_{6}$ input history in the study area, air sampling is being conducted in the area near the center of the island on a monthly and weekly basis. Based on the present data, the level of SF$_{6}$ concentration in the atmosphere of the Island is corresponding to the trend of the Northern Hemisphere.

• 한국연초학회지
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• 제20권2호
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• pp.198-204
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• 1998

This study was conducted to evaluate the effect of far IR radiation for the elimination of sidestream smoke components in a closed room. The measurements covered particle sizes of 13.8-542.5 nm, particle concentration, TSP, UVPM, FPM, solanesol, and the following gases and vapor components of smoke: carbon dioxide, carbon monoxide, nicotine, and 3-ethenyl-pyridine. Also, the changes of smoke odor strength by far IR radiation were tested by using the electronic nose system. There was no difference between control and far IR radiation in changes of the concentration of $CO_2$ and CO. The concentrations of TSP, UVPM, FPM, solanesol, nicotine, and 3-ethenylpyridine were reduced by far IR radiation. The growth and diminishing rate of RSP diameter was accelerated by far IR radiation compared with control. There was a little difference of smoke odor change with far IR radiation by electronic nose system analysis. Our results indicated that the use of far IR radiation had a little effect on changes of solid, vapor, and odor of smoke, but it had no effect on gaseous components.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.463-469
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• 2003

2개의 보조건물(PAB와 SAB)이 있는 KSNP의 경우, 단일 보조건물만을 고려하고 있는 PWR-GALE 코드를 이용하여 기체배출량을 평가하기에는 한계가 있다. 본 논문에서는 기존 PWR-GALE 코드는 그대로 이용하면서 KSNP의 설계특성을 반영하기 위하여 일부 입력변수를 수정해서 보조건물 옥소방사능 배출량을 사실적으로 평가할 수 있는 방법론을 개발했다. 울진 5,6 호기의 설계자료를 이용하여 기존 평가방법론과 개선된 평가방법론을 적용해 사례연구를 실시하였다. 기존 평가방법으로 보조건물 옥소의 유효제거효율을 산출한 결과 42%가 나왔으나 PAB와 SAB의 옥소핵종 농도가 동일하다고 가정을 만족하지 못하는 단점이 있다. 개선된 평가방법으로 옥소의 유효제거효율을 산출한 결과 88%가 나왔다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.455-462
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• 2003

원자력법에 의해 국내 모든 가동원전은 10년마다 주기적안전성평가를 이행하고 있다. 원자력법 시행규칙 제19조의 2에 제시된 환경영향 분야의 평가는 원자로시설의 환경영향 감시계획이 적절히 수립되어 이행되고 있는지를 확인하는 것이다. 평가결과 월성 1호기 가동에 따른 환경영향은 전반적으로 기술기준을 만족하였으며, 평가기준일까지 월성 1호기 운영으로 인해 주변 주민이 받는 방사선량은 제한치 이내에서 안전하게 관리되는 것으로 확인하였다.

• 한국대기환경학회지
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• 제16권6호
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• pp.585-594
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• 2000

Through an application of Micrometerorological methods, we conducted measurements of Hg fluxes from Nan-Ji-Do which is well known as one of the major local areal sources in Seoul metropolitan area during Match/April of 2000. In the course of our study, we determined the concentration gradients of total gaseous Hg(between 20 and 2000 cm heights) and combined these data with Micrometerorological components to derive is fluxes. It turned out that emission from and dry deposition to soil surfaces occurred at the ratio of 72:27 from a total of 271 hourly measurements. The validity of measured concentration gradients( or resulting fluxes) was evaluated in terms of percent gradient. Accordingly, about more than 95% of gradient data derived were statistically significant. The mean fluxes of Hg across soil-air interface, when computed using the concentrations gradients and relevant parameters, were found at 253(during emission) and -846ng/$m^2$/h(during dry deposition) The occurrences of abnormalously high exchange rates appear to be the combined effects of enormously high gradient values and high transfer coefficients. While the emissions of Hg occurred constantly during the whole study periods, the occurrences of dry deposition events were observed most intensively during very limited time periods(3/29 and 4/3). The results of our study cleary indicated that the studied area is a strong local areal source, while exhibiting great potential as a major sink simultaneously.

• 한국대기환경학회지
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• 제19권2호
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• pp.217-229
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• 2003

The amounts of nitrogen and sulfur deposited in the region of the Yellow Sea in both dry and wet forms were estimated by using the measurement data published in tile literature during tile past 10 years. In the estimation of dry deposition, concentrations at ground stations including those at a station on the Chinese side and concentrations from shipboard and aircraft measurements were used as well as deposition velocities. Wet deposition flux was determined at ground stations on the Korean side either by taking the flux data themselves or by calculating them from precipitation data in the literature. The dry deposition flux over the Yellow Sea was much greater than those China was confirmed from the fact that the total amount summing wet and dry depositions exceeded the emission amount from Korea. Dry deposition was principally made in the gaseous form due to a larger deposition velocity. Nevertheless, since the deposition velocity over water was smaller than that over the ground, dry deposition of oxidized nitrogen was smaller than wet deposition. As a whole, wet depositions of nitrogen and sulfur were 2.3 and 1.9 times 1arger than corresponding dry depositions, respectively.

• 한국염색가공학회지
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• 제24권2호
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• pp.131-137
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• 2012

para-Aramid fibers were treated by low-temperature plasma to improve the adhesion. The surface of para-aramid fibers were treated with gaseous plasma of several discharge power and treatment time in oxygen gas at 1Torr pressure. The treated fibers at low-temperature plasma were taken oxygen-containing functional groups and micro-crator on the surface. The modified fibers were measured by dynamic contact angle analyzer and XPS(X-ray photoelectron spectroscopy). The Interfacial adhesion properties of aramid fabric and polyurethane resin were determined by T-peel test. The surface of aramid fibers were observed by FE-SEM photographs. It was found that surface modification and chemical component ratio of the aramid fibers were improved wettability and adhesion characterization.

• 한국대기환경학회지
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• 제12권3호
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• pp.297-305
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• 1996

Aerosol measurements were carried out at Kosan, Cheju Island, Korea for the period from July 20 to August 10, 1994. Total suspended particles were collected by high volume samplers and PM 2.5 particles with gaseous volatile species were collected by a filter pack sampler and their ionic composition are analyzed. The average mass concentration of PM 2.5 particles was comparable to that of PM 3 particles collected during March, 1994 at the same site but the average non sea-salt sulfate concentration was higher that that of PM 3 particles, implying the fraction of anthropogenic air apllutants during this period is higher than that during March, 1994. During the measurement period, two distincitive patterns were observed, high concentrations of mass and water soluble ions were observed between July 20 and August 1 while those during after August 2 were low. Back trajectory analysis results show that air masses arriving at Kosan during the earlier period were mainly from Korea and Japan while those during the later period were from the North Pacific Ocean. It is suggested that the particle ion concentrations during the later period are marine background concentrations at Kosan during the summertime.

• 한국수소및신에너지학회논문집
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• 제13권3호
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• pp.249-258
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• 2002

Thermochemical water-splitting IS(Iodine-Sulfur) process has been investigating for large-scale hydrogen production. For the construction of an efficient process scheme, two kinds of membrane technologies are under investigating to improve the hydrogen producing HI decomposition step. One is a concentration of HI in quasi-azeotropic HIx ($HI-H_2O-I_2$) solution by elecro-electrodialysis. It was confirmed that HI concentrated from the $HI-H_2O-I_2$ solution with a molar ratio of 1:5:1 at $80^{\circ}C$. The other is a membrane reactor to enhance the one-pass conversion of thermal decomposition reaction of gaseous hydrogen iodide (HI). It was found from the simulation study that the conversion of over 0.9 would be attainable using the membrane reactor using the gas permeation properties of the prepared silica hydrogen permselective membrane by chemical vapor deposition (CVD). Design criterion of the membrane reactor was also discussed.

• 천문학회지
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• 제37권4호
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• pp.257-259
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• 2004

We compare the results of the surveys of starless cores performed with CS (2-1) and (3-2) lines to study inward motions in the cores. The velocity shifts of the CS(3-2) and (2-1) lines with respect to $N_2H^+$ are found to correlate well with each other and to have similar number distributions, implying that, in many cores, systematic inward motions of gaseous material may occur over a range of density of at least a factor ${\~}$4. Fits of the CS spectra to a 2-layer radiative transfer model in ten infall candidates suggest that the median effective line-of-sight speed of the inward-moving gas is ${\~}0.07 km\;s^{-l}$ for CS (3-2) and ${\~} 0.04 km\;s^{-l}$ for CS(2-1). Considering that the optical depth obtained from the fits is usually smaller in CS(3-2) than in (2-1) line, this may indicate that CS(3-2) usually traces inner, denser gas with greater inward motions than CS(2-1) implying that many of the infall candidates have faster infall toward the center. However, this conclusion may not be representative of all starless core infall candidates, due to the statistically small number analyzed here. Further line observations will be useful to test this conclusion.