• The Journal of Engineering Geology
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• v.22 no.1
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• pp.95-111
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• 2012

This study investigated the relationship between the geochemical environment and the occurrence of natural radioactive materials (uranium and Rn-222) in borehole groundwater at an Icheon site. The drill core recovered from the study site consists mainly of biotite granite with basic dykes. The groundwater samples were collected at four different depths in the borehole using the double-packed system. The pH range of the groundwater was 6.5~8.6, and the chemical type was Ca-$HCO_3$. The ranges of uranium and Rn-222 concentrations in the groundwater were 8.81~1,101 ppb and 5,990~11,970 pCi/L, respectively, and concentrations varied greatly with depth and collection time. The ranges of uranium and thorium contents in drill core were 0.53~18.3 ppm and 6.66~17.5 ppm, respectively. Microscope observations and electron microprobe analyses revealed the presence of U and Th as substituted elements for major composition of monazite, ilmenite, and apatite within K-feldspar and biotite. Although the concentration of uranium and thorium in the drill core was not high, the groundwater contained a high level of natural radioactive materials. This finding indicates that physical factors, such as the degree of fracturing of an aquifer and the groundwater flow rate, have a greater influence on the dissolution of radioactive materials than does the geochemical condition of the groundwater and rock. The origin of Rn-222 can be determined indirectly, using an interrelationship diagram of noble gas isotopes ($^3He/^4He$ and $^4He/^{20}Ne$).

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.2
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• pp.59-65
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• 1999

Both the groundwater changes due to different pumping rates and the geochemistry of thermal waters in the Suanbo area are considered in this study. The observation of groundwater level change since 1991 shows that the change is directly correlated with pumping rates of thermal waters and reveals the retardation of ca. 5 weeks after pumping. The hydrogeological aquifer in the area is under reducing condition. The thermal waters are of Na-HCO$_3$ type. and are alkaline (pH=8.5∼8.7) with low TDS values (274∼284 mg/l) and high concentrations of Na (68∼72 mg/l). F (6.4∼8.9 mg/l), and HCO$_3$(136∼146 mg/l). Oxygen and hydrogen isotope ratios of thermal water indicate a meteoric water origin. The activities of Rn-222 and Ra-226 in both thermal water and local groundwater were determined to delineate possible geochemical controls on the Rn-222 and Ra-226. The Rn-222 concentrations are several orders of magnitude greater than the Ra-226 concentrations. The concentrations of Rn-222 range from 190 to 7.490 pCi/1 with an average of 2,522 pCil/l. and those of Ra-226 average 0.32 pCi/1 with the range from 0.25 to 0.42 pCi/1. The concentrations of Rn-222 and Ra-226 are inversely correlated with EC and alkalinity. The pH it positively correlated with Ra-226. The correlation between Rn-222 and Ra-226 is poor. Thermal waters in the study area are produced from highly fractured phyllite. The thermal water qualify. CSAMT (controled-source audiofrequency magnetotelluric) prospecting, and petrological evidences, however, indicate that the heat is possibly transmitted through deep normal faults reaching a deep granite batholith, and the phyllite acts only as a groundwater pathway.

• Korean Journal of Optics and Photonics
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• v.11 no.6
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• pp.441-446
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• 2000

Wigner functions and density matrices are computer simulated for various quantum mechanical states of light. Wigner function and density matrices are evaluated by filtered back projection which includes inverse Radon transform from the distribution function of the photocurrents, which are calculated in the balanced homodyne detection scheme. The density matrix is also directly obtained by using the pattern function from the simulated phase independent photocurrent distribution function. ction.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1306-1312
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• 2011

Underground Subway station's air pollutants are introduced from the indoor or outdoor. And Radon is a major pollutant in the subway station. Radioactive substances Radon is occuring naturally in granite tunnel wall and underground water. Especially inert gas Radon that causes lung cancer in human is anywhere but 5678 S.M.R.T. tunnels deep and pass through the granite plaque have a lot of Radon. The Radon concentration is determined by the following reasons : radon content of soil and concrete, underground water, ventilation, pressure difference, building structure, temperature, etc. So Radon concentration is hard to predict. And we can't only ventilate owing to era of high oil prices. This study focuses on our efforts for the reduction of Radon concentration. And the purpose is to provide basically datas of specially managed 15 subway station's Radon concentration.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.208-213
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• 2011

Seoul Metropolitan Rapid Transit Corporation has 148's stations. Total length is 152km and most of the station is located in the basement and Groundwater occur inflow of 700,000 tons per day. Groundwater is treated as a natural flow way instead of artificial ways. Therefore, most of the collection wells is located in the low place or station for the efficient induction and collecting water. Manhole overtopping is occurring frequently because groundwater is concentrated in the drain pipe near the collecting well and heavy rainfall in summer. As a result, ballast contamination and radon levels are increased in tunnel. This paper introduces a solution is increasing overflow in tunnel, which introduces drainage system of non-motorized that uses differencial head between collecting well and manhole.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.699-704
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• 2006

본 논문은 회전 및 천이불변 이미지 텍스처 검색의 새로운 방식을 소개한다. 주파수 영역의 극좌표계에서 동일한 공간 주파수에서 각도 방향으로 투영을 하는 각도 투영법을 제안하며, 제안된 각도 투영법을 이용하여 주파수 영역에서 푸리에 계수이 합과 표준편차를 특징벡터로 이용한다. 각도 투영법을 쉽게 구현하기 위해 극좌표계에서 라돈변환이 수행된다. 실험 시 MPEG-7 데이터를 이용하였으며 그 결과는 여러 텍스처 이미지를 검색하는데 있어서 특징을 잘 구별해 내는 결과를 보여준다. 또한 제안된 회전 및 천이불변 특징 추출 알고리듬은 등방성 텍스처나 국부적인 방향성을 보이는 텍스처 영상 검색에도 효율적인 검색률을 보인다.

• Journal of Soil and Groundwater Environment
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• v.22 no.5
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• pp.63-70
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• 2017

Radon concentrations were measured in 250 groundwater samples collected from the Goesan area where uraniferous black slate and granites abundantly occur in the formations. The measured radon levels ranged from 0.90 to 7,218.7 Bq/L with the median value of 54.3 Bq/L, similar to the value measured in the nationwide survey in 4,853 wells (52.1 Bq/L). The median value was highest in the Cretaceous granite area (390.0 Bq/L) while it was as low as 20.0~58.8 Bq/L in the Ogcheon meta-sedimentary rock areas. About 23.6% of the total samples exceeded the WHO guideline value of 100 Bq/L established in 2011. The exceeding rate was 69.0, 39.4, and 7.0~13.7% in the Cretaceous granite area, Jurassic granite area, and Ogcheon meta-sedimentary rock areas, respectively.

• Journal of Environmental Health Sciences
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• v.28 no.5
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• pp.71-76
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• 2002

A survey of radon concentrations in both indoor and outdoor atmospheres was carried out using EIRM and Cup Monitor for the period of February 1996 to March 1997. EIRM were used to measure the indoor and outdoor radon concentration at five major cities university. Cup Monitor were also used to measure the indoor radon concentrations at shopping store, office building, apartment, hospital and house in Seoul. The mean indoor and outdoor radon concentrations at the five major cities(Seoul, Daegu, Daejon, Cwangiu and Busan) were 24.1 Bq/m$^3$and 8.62 Bq/m$^3$, respectively. The ratio of indoor to outdoor radon concentrations ranged front 1.7 to 3.9. Inspection of its seasonal distribute pattern indicates the enhancement during winter relative to summer, consistently for both indoor and outdoor air. The results of the survey showed that the concentrations in basements were clearly higher than those in usual living/working places.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.3
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• pp.241-249
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• 2001

A report by the National Research Council in the United States suggested that many lung cancer deaths each year are associated with breathing radon in indoor air. Most of the indoor radon comes directly from soil beneath the basement of foundation. Recently, radon released from groundwater is found to contribute to the total inhalation risk from indoor air. This study presents the assessment of a exposure to radon released from the groundwater into indoor air. At first, a 3-compartment model is describe the transfer and distribution if radon released from groundwater in a house through showering, washing clothes, and flushing toilets. The model is used to estimate a daily human exposure through inhalation of such radon for adults based on two sets of exposure scenarios, Finally, a sensitivity analysis is used to identify important parameters. The results obtained from the study would help to increase the understanding of risk assessment issues associated with the indoor radon released from groundwater.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.4
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• pp.327-334
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• 2002

The work presents sensitivity and uncertainty analysis of 2-compartment model for the evaluation of indoor radon pollution in a house. Effort on the development of such model is directed towards the prediction of the generation and transfer of radon in indoor air released from groundwater. The model is used to estimate a quantitative daily human exposure through inhalation of such radon based on exposure scenarios. However, prediction from the model has uncertainty propagated from uncertainties in model parameters. In order to assess how model predictions are affected by the uncertainties of model inputs, the study performs a quantitative uncertainty analysis in conjunction with the developed model. An importance analysis is performed to rank input parameters with respect to their contribution to model prediction based on the uncertainty analysis. The results obtained from this study would be used to the evaluation of human risk by inhalation associated with the indoor pollution by radon released from groundwater.