• Journal of Radiation Protection and Research
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• v.32 no.3
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• pp.97-104
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• 2007

The corelation between the indoor volume and the measured radon concentration has been analyzed by comparing the radon concentration and the indoor volume of apartment rooms in Jeonju City. We also measured the annual exposure dose based on the variation in indoor radon concentration over time. To do this, we took 8 larger rooms and 8 smaller rooms of apartment, respectively, as a sample. The average volume of the larger rooms and that of the smaller rooms were $31.59\;m^3$ and $16.82\;m^3$, respectively. The average radon concentration of the larger rooms and that of the smaller rooms turned out to be $71.73\;Bq/m^3$ and $108.51\;Eq/m^3$, respectively. indicating that indoor volume is in inverse proportion to the radon concentration, i.e., the bigger the ratio of the surface area/volume, the higher the indoor radon concentration. From the measurement of the variation in indoor radon concentration over time fur a single day, the average intraday radon concentration variation was found to be about $46.8\;Bq/m^3$. The highest level of concentration ($114.5\;Bq/m^3$) was measured between 8 and 10 AM and the lowest level of concentration ($67.7\;Bq/m^3$) between 2 and 4 PM. The annual exposure dose turned out to be in the range of 0.3 mSv/yr to 2.16 mSv/yr, showing that the dose in some apartments exceeded 1.3 mSv/yr, the numerical value presented by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR).

• Proceedings of the Korea Information Processing Society Conference
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• 2018.05a
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• pp.600-601
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• 2018

미세먼지가 심각한 요즘 폐질환 환자 수가 점점 늘어나고 있다. 현재 미세먼지 농도를 줄일 수 있는 근본적인 방안은 없으며, 폐질환 환자는 외출 시 마스크를 착용하거나 자제하는 방법뿐이다. 외출을 하기 전에는 한국환경공단에서 제공해주는 미세먼지 농도의 정보를 가지고 마스크 착용 유무를 판단해야만 한다. 하지만, 제공받은 미세먼지 데이터의 범위가 넓기 때문에 가까운 곳으로 잠깐 외출하는 경우 먼지 농도의 정확한 정보를 제공받기가 어렵다. 10m 정도 앞의 거리의 미세먼지 농도를 알 수 있다면 외출 시 도움이 될 것이라 생각하였다. 따라서 드론을 이용하여 미세먼지 농도를 측정하여서 내가 가고자 하는 가까운 장소의 미세먼지를 측정하는 연구를 하고자 한다. 이를 통해 내가 원하는 가까운 곳의 미세먼지 농도를 자유롭게 알고자 한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.449-450
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• 2019

본 논문에서는 차량 내 이산화탄소 농도 측정을 통해 운전자의 졸음운전을 예방하는 모델을 제안한다. 제안된 모델은 이산화탄소 농도 측정 센서를 연결한 아두이노 보드를 차량 내부에 부착하여 측정된 수치를 실시간으로 분석한다. 분석된 수치를 운전자, 탑승자에게 전송하여 자발적으로 졸음 방지를 유도한다. 또한 설정된 수치 이상인 경우 차량 내 사용자와 차량 외 보호자에게도 경고 메시지를 전송하고 차량 내 공기 상태를 알린다. 추후 차량 내 환경과 운전 시간, 탑승자 정보 등을 활용하여 전송된 수치를 분석하면 운전 환경 개선을 위한 방안을 모색할 수 있다.

• 전기의세계
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• v.28 no.12
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• pp.12-18
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• 1979

물질의 양을 계측하는 소위 분석기기는 광, 전기, 자기 및 크로마트 등 많은 물리적 화학적 특성을 이용한 계측기가 있으며 또한 측정목적에 적합한 원리의 계측기가 사용되고 있다. 환경대기나 배가스의 측정기기도 특별한 것이 아니고 보통의 분석기기를 이용하고 있다. 또한 발생원(카드뮴, 연 및 그의 화합물)과 환경에 있어서 배진이나 분진(이하 더스트라고 총칭함)에 의한 공해방지를 위하여 법에 의한 규제와 기준에 대한 적부의 판단을 비롯해서 공해방지장치(집진장치등)의 성능측정 또는 오염예측 등에 각종 측정기기가 사용되고 있다. 이것들은 주로 더스트의 농도, 양, 조성및 입경분포 등을 측정하는 것이나 이외에 필요에 따라서 여러가지 성상(비중, 전기저항율 등)을 측정할 수 있다. 그러나 본고에서는 가장 측정빈도가 높은 농도의 측정을 중심으로해서 가장 적절한 측정기기의 선정요점을 기술하고자 한다.

• 산업보건소식
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• no.38
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• pp.28-31
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• 1987

노동부는 유해물질의 허용농도를 작업환경측정방법과 분리하여 각각의 규정을 제정함으로써 허용농도설정의 근본취지에 부합되게 하는 동시에 허용농도 제정대상 유해물질의 종류를 394종(현재 60종)으로 확대하여 산업안전보건법 제18조 및 동법 제31조 규정에 의한 작업환경개선 및 평가의 기준 으로 사용할 수 있도록 유해물질의 허용농도를 고시 제 86-­45호로 제정하고 현행 작업환경측정방법을 고시 제 86-46 호로 개정하였으며 '87.4.1 부터 시행한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.307-310
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• 2015

부유사량을 알기위해 측정하는 방법은 여러 가지가 있다. 대표적인 방법으로는 측정기기를 이용하여 수심에 따라 일정하게 시료를 채취하는 방법과 일정 수위에서 포인트 개념으로 시료를 채취하는 방법이 있다. 이 측정법들은 일반적으로 수심에 따른 유속과 부유사농도가 다르게 나타나기 때문에 오차를 최소화하기위해 측정하는 방법들이다. 홍수 시 부유사량 농도는 유역특성, 하상재료, 강우특성 등에 따라 부유사농도가 다양하게 나타나지만 측정현장에서 발생하는 부유사농도는 사람의 시각적으로 판단 할 수 없을 정도의 황토빛 흐름이 발생한다. 또한, 여러 안전상 문제점이 발생하기도 하며 수위 상승부에서는 수위가 급격히 증가하는 현상을 보여 측정에 어려움이 발행하는 등 예상할 수 없는 여러 문제점이 발생한다. 본 연구에서는 부유사량 채취 시 표면채취법과 수심적분법을 비교 검토하여 차이점을 분석하고 부유사량 산정 및 측정지점의 특성을 확인하여 보았다.

• Clean Technology
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• v.26 no.4
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• pp.293-303
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• 2020

According to the World Health Organization (WHO), air pollution is a typical health hazard, resulting in about 7 million premature deaths each year. Sulfur dioxide (SO2) is one of the major air pollutants, and the combustion process with sulfur-containing fuels generates it. Measuring SO2 generation in large combustion environments in real time and optimizing reduction facilities based on measured values are necessary to reduce the compound's presence. This paper describes the concentration measurement for SO2, a particulate matter precursor, using a wavelength modulation spectroscopy (WMS) of tunable diode laser absorption spectroscopy (TDLAS). This study employed a quantum cascade laser operating at 7.6 ㎛ as a light source. It demonstrated concentration measurement possibility using 64 multi-absorption lines between 7623.7 and 7626.0 nm. The experiments were conducted in a multi-pass cell with a total path length of 28 and 76 m at 1 atm, 296 K. The SO2 concentration was tested in two types: high concentration (1000 to 5000 ppm) and low concentration (10 ppm or less). Additionally, the effect of H2O interference in the atmosphere on the measurement of SO2 was confirmed by N2 purging the laser's path. The detection limit for SO2 was 3 ppm, and results were compared with the electronic chemical sensor and nondispersive infrared (NDIR) sensor.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.556-563
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• 2020

The purpose of this study was to verify the antioxidant and whitening effects of fermented Ambrosia trifida L. extract (ATFE) and to verify its usefulness as a cosmetic material. The antioxidant effects were measured by assessing the electron-donating capacity and 2,2-azino-bis(3-ethyl-benthiazoline-6-sulfonic acid) (ABTS) radical scavenging ability of these extracts. ATFE was shown to have an electron-donation capacity of 68.4% at a concentration of 1000 ㎍/ml. While its ABTS+ radical scavenging ability was shown to be 58.7% at the same concentration. The ATFE tyrosinase inhibitory effect, which is related to skin-whitening, was shown to be 32.35% at a concentration of 1000 ㎍/ml and a cell viability assay using melanoma cells showed a 14.8% reduction in cell viability at a concentration of 100 ㎍/ml. Surviving cells were then used in western blot analyses to evaluate the protein inhibitory effects of ATFE at 25, 50, 100 ㎍/ml where β-actin was used as a positive control. The whitening effects of these extracts were also evaluated by western blot and show that the expression of microphthalmia-associated transcription factors, Tyrosinase-related proteins (TRP)-1, TRP-2 and Tyrosinase were all inhibited, 51.14%, 55.4%, 38.6%, 83.77% respectively, at 100 ㎍/ml ATFE. The efficacy of the whitening effects was verified and the suitability of ATFE as a cosmetic material was assured.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2008.04a
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• pp.199-205
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• 2008

In this study, a system to measure continuously the fuel concentration in a steady flow rig on the basis of Rayleigh scattering is presented. The system can be employed to measure both the temporal and the spatial distribution. Also, it is possible to calibrate the system for the measurement of accurate absolute concentration. Firstly, the system was tested at a calibration chamber for the determination of scattering cross section from propane, butane, acetylene, Freon-12 and Genetron 143a. After this, the system was adapted to a steady flow rig to measure the temporal and spatial fuel concentration. The rig is composed of cylinder head, intake manifold, injector, and transparent cylinder which can simulate internal combustion engine. To cope with the problem of Mie scattering interference, a software filter was developed, which is based on the rise time and the time constant of the photomultiplier-amplifier system. The results show that LRS can provide useful informations about concentration field and the software filter is very effective method to remove Mie interference.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.1
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• pp.1-8
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• 2015

To evaluate accuracy and precision of determination of total alkalinity ($Alk_T$) and carbon dioxide ($TCO_2$) derived from present study, experiment was applied with $CO_2$ CRM (Batch 132, Scripps Institution of Oceanography; $Alk_T=2229.24{\pm}0.39{\mu}mol/kg$, $TCO_2=2032.65{\pm}0.45{\mu}mol/kg$). As the result, average concentration of $Alk_T$ and $TCO_2$ was $2354.09{\mu}mol/kg$ (~5.6% difference with $CO_2$ CRM) and $2089.60{\mu}mol/kg$ (~2.3% difference with $CO_2$ CRM), respectively. For previous method (Gran Titration) by addition $NaHCO_3$ to deionized water($Alk_T$ $2023.33{\mu}mol/kg$), average concentration was $2193.39{\mu}mol/kg$ (sd=57.15, n=7). Whereas, average concentration was $2017.02{\mu}mol/kg$ (sd=10.98, n=7) for the present study. Recovery yield experiments of total alkalinity in deionized water and seawater were implemented by addition of $NaHCO_3$. The recovery yield of deionized water in the range 0 to $4952.39{\mu}mol/kg$ was 100.8% ($R^2$=0.999), and seawater in the range 0 to $2041.32{\mu}mol/kg$ was 102.3% ($R^2$=0.999). Comparison of $pCO_2$ sensor (PSI $CO_2-Pro^{TM}$) with present method showed very meaningful correlation coefficient ($R^2$=0.977) in the range of 427 to $705{\mu}atm$ and 9.16 to $15.24{\mu}mol/kg$ throught elapsed time for two weeks. Field experiment of diurnal variation of total carbon dioxide was accomplished at Sachon harbor in the coastal waters of East Sea of Korea. Concentration of $Alk_T$ and $TCO_2$ was increased during night, and decreased during daylight hours. The results showed mirror type between $TCO_2$ and dissolved oxygen, which was attributable to photosynthesis and respiration of phytoplankton. Also, open ocean field study was performed to obtain vertical profile of $Alk_T$ and $TCO_2$ in C-C zone (Clarion-Clipperton Fracture Zone), Northeastern Pacific. Average concentrations of $Alk_T$ in the surface mixed layer (0~60 m) and deeper layer below 200 m were $2422.38{\mu}mol/kg$ (sd=78.73, n=20) and $2465.87{\mu}mol/kg$ (sd=57.68, n=103), respectively. And average concentrations of $TCO_2$ were $2134.47{\mu}mol/kg$ (sd=65.4, n=20) and $2431.87{\mu}mol/kg$ (sd=65.02, n=103) in the same depth ranges such as $Alk_T$. Vertical distributions of $Alk_T$ and $TCO_2$ concentrations tended to increase with depth, and analyzed concentrations showed slightly higher than those of previous studies in this area.