• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.257-261
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• 2015

Radon is produced after the Uranium-238 and thorium-232 undergone radioactive decay process is a colorless, odorless inert gas is stored in a basement or an enclosed space. Building materials are made by a rock or soil materials. Form of radon gas is introduced into the lungs through the respiratory tract and deposited in the lungs or bronchial Daughter nuclides radon causes lung cancer. In this study, To subject the Constructed Apartment in Gwangju Gwangsan-Gu, the position is closed window and opened window was measured using a measuring instrument for radon. The measured results indicate that the measurement was carried out in concentrations of radon gas measured at Newly Constructed Apartment is low than United states in the radon concentration in air public 4 pCi called radon gas baseline maximum allowable concentrations. The exposure caused by radon concentration of new construction apartment when on the measurement results is expected to be insignificant. However, when radon gas like this is that it accumulates in the body and lungs get damaged due to exposure, such as lung cancer often open the windows to reduce the radon concentration measurements, such as in radiation protection aspects to the ventilation to reduce exposure it is considered necessary.

• Nuclear Engineering and Technology
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• v.11 no.2
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• pp.105-110
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• 1979

In order to evaluate the effect of gamma ray irradiation to the soils added with several organic matters on release sad fixation of $^{65}Zn$, a soil incubation test was carried out by use of an acidic and a calcareous soil. The results obtained were summarized as follows : DTPA extractable $^{65}Zn$ decreased gradually with elapsed time of incubation owing to fixation of $^{65}$Zn by the soils but after four weeks DTPA extractable $^{65}Zn$ was reached an equilibrium state. The most parts of $^{65}Zn$ activity in the equilibrium state was found in the solid phase. The extent of zinc fixation in acidic Keumgok and calcareous Jecheon soils represented as activity basis was 89 and 93.7 per cent of applied $^{65}Zn$ respectively. Increased tendency of DTPA extractable zinc was shown by irradiating gamma ray to both soils because of $^{65}Zn$ fixation could be decreased by irradiation. The extractability of fixed $^{65}Zn$ by DTPA solution was 38.9 per cent in acidic Keumgok soil and only 9.5 per cent in calcareous Jecheon soil. Release of fixed $^{65}Zn$ by irradiation of gamma ray is closely related to pH of both soils. Much more $^{65}Zn$ could be released under low pH condition. Effect of gamma ray irradiation to organic matter sources on release of $^{65}Zn$ could not be differentiated. But in the case of nonirradiated soils, however, glucose treated soils couldrelease much more the extractable zinc as compared to those of the straw or cellulose treatment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.500-506
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• 2015

In this paper, we designed and fabricated the EM wave absorber consisted of Sendust for suppressing EM wave noise PCB in ISM (Industrial, Scientific and Medical) band of 2.4 GHz. We fabricated several samples with different composition ratios of some kinds of Sendust to CPE (Chlorinated Ploy-ethylene) as a binder, and it was confirmed that the optimum composition ratio of absorbing materials was Flaked Sendust : CPE = 72.5 : 27.5 wt.%.. The absorbing abilities were simulated by changing the thickness and the measured material constants of EM wave absorber. The measured absorption abilities were analyzed and compared with the simulated ones. As a result, the simulated results agree well with the measured ones, and the developed EM wave absorber with extremely thin thickness of 0.6 mm has absorption ability of 5.4 dB at 2.4 GHz is excellent one. The thin type EM wave absorber can be applied for suppressing and absorbing electromagnetic noises from information and communication equipments.

• The Journal of the Petrological Society of Korea
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• v.18 no.4
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• pp.279-291
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• 2009

Radon is a natural radionuclide originated from radioactive decay of radium in rocks and soil. It is colorless, odorless and tasteless elements that mainly distributed as gaseous phase in soil pore space. The present study analyzed the characteristics of long-term radon variation in granitic residual soil at Mt. Guemjeong in Guemjeong-gu, Busan and determined the effects of atmospheric temperature, rainfall and soil temperature and moisture. Periodic measurements of radon concentrations in soil gas were conducted by applying two types of in-situ monitoring methods (chamber system and tubing system). Radon concentration in soil gas was highest in summer and lowest in winter. The variations in soil temperature and atmospheric temperature were most effective factors in the long-term radon variations and showed positive co-relations. The air circulation between soil air and atmosphere by the temperature difference between soil and atmosphere was analyzed a major cause of the variation. However, other factors such as atmospheric pressure, rainfall and soil moisture were analyzed relatively less effective.

• Archives of design research
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• v.17 no.1
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• pp.25-36
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• 2004

The purpose of this study is to analyse and interpret the way of differentiated expression and changing creative trend following 5-day workweek which has been recently adopted. For this aim 11 pieces of distinctive advertising text were analysed. The criteria for selection of analysing text were relativeness with 5-day workweek and cognitive inconsistency. These texts were negative phrases, exaggerated expression, and excessively humorous appeals. The study revealed the followings: First, 5-day workweek concerned advertising texts were considered as high attention getting and successful in stimulating advertising audiences' curiosity by using the elements opposing the value and belief system formed in the existing audience. Second, consumption-driving lifestyle was found in most expressions for credit cards advertising. Third, hedonic need-oriented lifestyle was typical in young consumer products category. Fourth, family centered lifestyle emphasized meaning of rest and solidarity of family.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2003.05a
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• pp.53-53
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• 2003

남한에 분포하는 현생 화강암류는 트라이아스기-쥬라기의 소위 대보화강암과 백악기-제3기의 불국사화강암으로 분류되어 왔다. 대보조산운동은 대동누층군의 퇴적이후에 일어난 조구조운동을 지칭하므로 트라이아스기의 화강암을 포함하는 대보화강암이라는 명칭은 그와 사실상 직접적인 관계는 없다. 트라이아스기-쥬라기의 화강암은 영덕, 청송 암체 외에는 경상분지 밖에 위치하고 백악기-제3기의 화강암은 속리산, 월악산 암체 외에는 경상분지 안쪽에 주로 분포한다. 트라이아스기-쥬라기의 화강암 중 영광-대전-청주-충주-원주-강릉 방면에 걸쳐 북동-남서 방향으로 분포하는 화강암질 저반은 남한에서 가장 넓은 면적을 차지하는 화강암체지만 신뢰할만한 연대측정 자료가 매우 부족한 실정이다. 이 화강암질 저반에 대해서는 Rb-Sr, K-Ar법이 해답을 주기 어렵다. 예를 들어 청주-음성-증평 지역의 화강암류에 대한 Rb-Sr 전암 자료는 분산이 심하며 약 380 Ma에 해당되는 초시선을 보여 기원물질의 불균질성 내지 불완전한 혼합 효과를 반영하고 있다. 옥천대와 영남육괴에 분포하는 일부 화강암체에 대해 잘못 보고된 Rb-Sr 전암연대 역시 모두 중광물의 U-Pb 연대보다 오래된 값을 보이는 것으로 보아 이들은 생성 당시부터 일정한 $^{87}$ Sr/$^{86}$Sr 초기치를 가지지 않고 Rb/Sr 비에 따른 양(+)의 기울기를 가졌음이 확실하다. 과잉의 방사기원 Ar을 가지거나 폐쇄온도가 낮은 광물들을 대상으로 한 K-Ar 자료 역시 화강암체의 관입편대를 정확하게 지시할 수는 없다. 우리는 이에 대한 연구의 일환으로 충청남도 청원군의 물류센터에서 채취한 중립질의 흑운모화강암 한 시료에 대한 U-Pb 스핀연대측정 결과를 다음과 같이 보고한다. $^{206}$ Pb$^{*}$ /$^{238}$ U age = 174.6$\pm$2.7 Ma $^{207}$ Pb$^{*}$ /$^{235}$ U age = 170.3$\pm$14.6 Ma $^{207}$ Pb$^{*}$ /$^{206}$ Pb sup */ age = 111$\pm$187 Ma 위에서 볼 수 있듯이 청주화강암의 스핀에 대해 콘코던트(concordant)한 연대가 얻어졌으며 자료의 오차, 스핀의 U-Pb계에 대한 폐쇄온도 및 화강암의 솔리더스(solidus)를 고려할 때 $^{206}$ Pb$^{*}$ /$^{238}$ U 연대인 174.6$\pm$2.7 Ma를 관입정치시기로 해석한다. 동일 시료의 흑운모에 대해서는 145 Ma의 Rb-Sr 연대가 얻어졌으며 따라서 관입이후 약 35$0^{\circ}C$까지 대략 1$0^{\circ}C$/Ma의 냉각속도를 구할 수 있었다. 청주화강암의 쥬라기 중기 연대는 영광-대전-청주-충주-원주-강릉 지역의 화강암질 저반이 대동누층군 퇴적 이후에 일어난 지구조 사건과 연관되었을 가능성을 지시하지만 이를 확인하기 위해서는 더 많은 자료가 요구된다. 우리는 현재 충주, 괴산 지역의 화강암체에 대해서도 스핀 연대측정을 수행중에 있으며 이들 자료를 암상을 구분하여 해석한다면 우리나라 중생대 지구조운동에 대한 새로운 사실이 밝혀질 수 있을 것으로 믿는다.

• Journal of the Korean Society of Radiology
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• v.12 no.6
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• pp.719-725
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• 2018

After 9/11 attacks in the U.S, Terrorism has increased the number of unspecified casualties through multi-use facility terror attacks compared to the past. The subsequent London bombings and the self-destruction of Pakistan increased people's fear and social anxiety. As international events have been held in Korea recently, awareness and concern over radioactive terrorism and security management of radioactive materials are increasing. In this paper, we compared the results of different meteorological conditions using HotSpot Code. After creating a possible terror scenario in Korea, sources likely to be use in RDD and Dirty bomb were investigated. The meteorological condition was selected by comparing the Pasquill-Gifford stability class with the most stable condition F and the most unstable condition A. The result value of the A and F condition through simulation were shown not to cause citizens to die from acute effects due to radiological effects. The range of radioactivity is different according to the wind speed and the meteorological stability, and the degree of radioactivity dilution is different according to meteorological conditions. Analysis results are expected to be used for initial response in the event of a radioactive terrorist attack.

• Tunnel and Underground Space
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• v.28 no.6
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• pp.596-608
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• 2018

As urban infrastructure is aging, the possibility of accidents due to the failures or breakdowns of infrastructure increases. Especially, aging underground infrastructures like sewer pipes, waterworks, and subway have a potential to cause an urban ground sink. Urban ground sink is defined just as a local and erratic collapse occurred by underground cavity due to soil erosion or soil loss, which is separated from a sinkhole in soluble bedrock such as limestone. The conventional measurements such as differential settlement gauge, inclinometer or earth pressure gauge have a shortcoming just to provide point measurements with short coverage. Therefore, these methods are not adequate for monitoring of an erratic subsidence caused by underground cavity due to soil erosion or soil loss which occurring at unspecified time and location. Therefore, an alternative technology is required to detect a change of underground physical condition in real time. In this study, the feasibility of a novel magnetic resonance based monitoring method is investigated through laboratory tests, where the changes of path loss (S21) were measured under various testing conditions: media including air, water, and soil, resonant frequency, impedance, and distances between transmitter (TX) and receiver (RX). Theoretically, the transfer characteristic of magnetic field is known to be independent of the density of the medium. However, the results of the test showed the meaningful differences in the path loss (S21) under the different conditions of medium. And it is found that the reflection coefficient showed the more distinct differences over the testing conditions than the path loss. In particular, input reflection coefficient (S11) is more distinguishable than output reflection coefficient (S22).

• Journal of the Korean Society of Radiology
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• v.14 no.7
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• pp.857-862
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• 2020

In March 2011, a tsunami off Japan caused radioactive material that had seeped into the sea from the Fukushima nuclear accident to flow to the Pacific Ocean, causing pollution to sea life. For a comparative evaluation with the area surrounding the site of a nuclear power plant by the release of radioactive materials, an area 20 to 30 km away from the emergency protection plan area was selected as a comparative point considering weather conditions, population distribution, etc. In addition, the government intends to analyze the minimum detection radiation received by residents around the nuclear power plant and evaluate the effective dose. Analysis of tritium radiation from water samples showed that most of the samples were not detected and that 0.0014 % to 0.777 % of the annual legal standard of 1 mSv for the general public had little effect on the human body. Therefore, the measurement and analysis of water samples around the nuclear power plant site is expected to help relieve anxiety, such as exposure to the general public and neighboring residents due to radiation release.

• Journal of Mushroom
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• v.18 no.4
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• pp.387-392
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• 2020

Eight dried ear mushroom products (three domestic and five Chinese products) distributed in Korea were analyzed for 321 residual pesticides, 7 heavy metals, and 3 types of radioactivity. Residual pesticides in the domestic products were not detected. However, chlorpyrifos, isoprocarb, mepiquat chloride, and carbendazim were detected in four Chinese products, all of which were below the allowable residual limit. Among the detected pesticide ingredients, only the residue for mepiquat chloride has been established to be present in ear mushrooms. In the heavy metal test, trace amounts of heavy metals were detected in all samples. However, none of the samples exceeded the allowable residual limits, except for one domestic sample that exceeded the standard value of 0.3 mg/kg for lead. Radioactivity tests confirmed that levels were below the minimal detectable activity value in all samples.