• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.4
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• pp.295-300
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• 2015

The precise determination of the activity for each radionuclide in environmental samples requires the self-absorption correction factor. In this research, we derived the self-absorption correction factor for three p-type high purity germanium detectors using the Monte Carlo code MCNPX. These detectors have different characteristics such as crystal diameter, height and size of the core. We compared the calculated full-energy peak efficiency with the experimental value using a standard sample with $1g/m^3$ density and verified the modeling. We simulated the dependency of the full-energy peak efficiency on the 0.3, 0.6, 0.9, 1.0, 1.2 and $1.5g/m^3$ samples and obtained the corresponding self-absorption correction factor. The self-absorption correction factors calculated for the three detectors differ by less than 1% over most of the energy range and sample densities considered. This indicates that the self-absorption correction factors are independent of the crystal characteristics of HPGe detector.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.155-163
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• 2009

The Oriental white stork (Ciconia boyciana) is an endangered species in Korea as well as in the world. In order to provide information on foraging habitats for releasing storks to the wild, we studied the foraging behavior of the species according to different food densities and water levels. We released two individuals, male and female, after enclosing a study site with a fence and cutting out a part of two or three primary feathers. Research was conducted from 20 June to 16 August 2008 at Whawon-ri, Mewon-myung, Chungcheongbuk-do, South Korea. We investigated habitat patch usage, foraging efficiency, and foraging methods of the feeding individuals in the different food densities and water levels. The storks invested more for foraging time and trials, and they captured more food in a habitat of high food density than others. The female invested more time and captured food most in a habitat of lowest water depth while the male in a habitat of middle water depth. However, foraging efficiency did not differ significantly among habitats of food density and water depth, and only differed between male and female by ways of foraging method. From this study we suggest that the storks select foraging habitats and foraging methods under different conditions of food density and water depth.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.2
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• pp.32-38
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• 1999

In this study, an objection is to develop a electronic circuit of a gauage using radioisotope for compaction control to be needed at public works The developed gauage makes use of radioisotope with the activity exempted from domestic atomic law and consists of measuring circuits for gamma-rays and thermal neutrons, a high voltage supply unit and a microprocessor. To obtain meaningful numbers of pulse counts, parallel five and tow circuits are provided for gamma-rays and thermal neutrons, respectively. Also, to minimize effects of natural environmental radiation and electrical noise, circuits are electrostatically shielded and pulses made by ripples are eliminated by taking frequency of high voltage supplied to the circuit and pulse height of ripples into consideration One-chip microprocessor is applied to process various counts, results are stored, Enough and meaningful numbers of pulses are counted with the prototype gauage for compaction control.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.3
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• pp.275-284
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• 2006

In the measurement of gamma rays emitted from the nuclide in the radioactive waste drum, to analyze the nuclide concentration accurately, it is necessary to use the proper calibration standards and to correct for the attenuation of the gamma rays. Two drums having a different density were used to analyze the nuclide concentration inside the drum in this study. After carrying out the system calibration, we measured the gamma rays emitted from the standard source inside the model drum with changing the distance between the drum and the detector. The measured values were corrected with the three kinds of gamma attenuation correction methode, as a results, the error was less than 10 % in the low density drum and less than 25 % in the high density drum. The measured activity in the short distance was more accruable than in the long distance. The transmission correction for the mass attenuation showed good results(very Low error) compared to the mean density and the differential peak correction method.

• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.49-58
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• 2012

Greenhouse whitefly, $Trialeurodes$ $Vaporariorum$, is the most important insect pest in environmental friendly tomato production. Natural enemies, $Nesidiocoris$ $tenuis$ and environmental friendly agricultural materials (EFAM) are major control agents in Korea. The aim of the present work is to evaluate release time of $N.$ $tenuis$ in controlling of $T.$ $vaporariorum$ and to select environmental friendly agricultural materials (EFAM) to suppress both $T.$ $vaporariorum$ and $N.$ $tenuis$ which if the density were high causing necrotic rings. Six EFAM selected to control of $Trialeurodes$ $Vaporariorum$ in three times spray with seven days intervals. Three EFAM showed high mortality 67.7-70.5% in spray after release plot but low in release after spray plot. It should be careful to spray with $N.$ $tenuis$. When $N.$ $tenuis$ were early release at 7 days after transplanting which before occurring and establishment of greenhouse whitefly, it could suppress the density. Extracts of bead tree + matrin, matrin 1, Chrysanthemum showed high mortality on $T.$ $vaporariorum$ adults and $N.$ $tenuis$. The results suggested that this three EFAM could be control agents of the damage of necrotic rings from $N.$ $tenuis$.

• Geophysics and Geophysical Exploration
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• v.24 no.1
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• pp.20-27
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• 2021

Subsurface rock produces heat from the decay of radioactive isotopes in constituent minerals and gamma-ray emissions, of which the magnitude is dominated by the contents of the major radioactive isotopes (e.g., U, Th, and K). The heat production is generally calculated from the rock density and contents of major isotopes, which can be determined by mass spectrometry of drilled core samples or rock fragments. However, such methods are not easily applicable to deep boreholes because core samples recovered from depths of several hundred meters to a few kilometers are rarely available. A geophysical logging technique for boreholes is available where the U, Th, and K contents are measured from the gamma-ray spectrum. However, this technique requires the density to be measured separately, and the measurement depth of the equipment is still limited. As an alternative method, a normal gamma-ray logging tool was adopted to estimate the heat production from the total gamma activity, which is relatively easy to measure. This technical report introduces the development of the proposed method for evaluating the heat production of a granitic rock mass with domestic commercial borehole logging tools, as well as its application to a ~2 km deep borehole for verification.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.866-871
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• 1995

방사성 폐기물 처분장 주변에서의 지하수 유동에 대한 민감도 분석을 수행하여 안전성 평가측면에서 필요한 성능측도에 미치는 영향을 파악하였다. 각 암반충의 투수계수 및 공극률의 변화에 대한 지하수 유속과 수두의 민감도와 경제 조건을 변경함으로 인해 지하수 유동시간에 미치는 영향을 adjoint 민감도 분석법에 의해 살펴보았다. 민감도 분석 결과, 본 논문에서 고려된 처분부 지의 경우 해수에 접한 경계 면에서는 해수의 밀도를 고려한 경계조건을 사용하는 것이 지하수 유동이 없다고 가정하는 경계조건보다 약간 보수적임을 보여주었고, 투수계수 변화에 따른 지하 수두 및 Darcy 속도는 처분동굴이 위치한 암반의 투수계수 변화에 매우 민감하고 실제적으로 동굴에서 멀리 떨어진 바닥 암반층의 투수계수 변화에는 민감하지 않았다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.127-129
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• 2020

높은 에너지 밀도, 장 수명 등의 특성을 갖는 리튬계열 축전지는 다양한 어플리케이션에 활용되고 있다. 그러나, 리튬계열 축전지의 열화로 인한 출력 특성 저하는 원전 사고 시, 안정적인 전력 공급을 저해하므로 원전 적용을 위해서 리튬계열 축전지의 열화를 일으키는 방사선에 대한 리튬계열 축전지의 강건성 검토가 필요하다. 본 논문은 방사성 동위원소 Co-60, 총 방사선량 100Gy의 저 준위 방사선 조사 시험을 진행하였으며, 이에 따른 리튬계열 축전지의 특성 비교를 위해서 전기적 특성분석 방법을 이용하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.275-275
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• 2012

바이오메디칼 연구에 있어서 최근 플라즈마의 사용이 급격하게 늘어나고 있다. 세포나 세균에 플라즈마를 조사하여 이에 대한 반응성 연구와 의료용 살균기 등 여러 방면에서 필요로 하고 있다. 현재 주로 단일 플라즈마 소스를 이용한 실험이 진행되어가고 있다. 그러나 이러한 방식은 다양한 실험을 하기에는 시간이 다소 많이 걸리는 단점이 있다. 이에 다양하고 좀 더 정확한 연구를 위한 균일하게 방사되는 대기압 멀티 플라즈마 소스가 필요하다. 대기압 멀티플라즈마 소스는 각각 발생하는 플라즈마가 동일한 밀도 및 전자온도를 유지할 수 있도록 하는 것이 쉽지 않다. 이와 같이 상황에 맞는 소스를 제작하는 것도 중요하다. 본 연구에서는 24-well tissue culture testplate에 맞는 4개의 대기압 플라즈마 제트가 발생하는 소스를 목표로 하였다. 균일한 플라즈마가 발생할 수 있도록 시뮬레이션을 통하여 멀티 플라즈마 소스를 개발 및 제작하였다. 이에 대한 플라즈마 분석과 기초실험을 진행하여 재현성 테스트를 하였다.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.237-247
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• 2020

Purpose: This study aims to draw the problems and improvements of NFSC 103 sprinkler head discharge obstruction prevention standard to increase the fire extinguishing performance of sprinkler system in order to contribute to the protection of people's lives and property in the event of a fire. Method: NFSC 103 was compared to NFPA 13 which is the latest 2019 version in U.S in terms of sprinkler head discharge obstruction prevention. Results: This study found that NFSC 103 doesn't define even the basic concept of sprinkler discharge obstruction. And NFSC 103 doesn't have detailed standard for side wall sprinkler head discharge obstruction prevention as well as the "height" criteria of the "three times" separation rule. Conclusion: NFSC 103 needs a lot of supplements and improvements such as the addition of definition for water discharge obstructions, the adoption of sidewall sprinkler heads standard for preventing water discharge obstructions and the additional establishment of the "three times rule" considering the "height" of obstacles to promote the advance of fire safety standard equal or above fire fighting advanced country and increase the reliability for the suppression performance of sprinkler system.