• Journal of Radiation Protection and Research
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• 제24권3호
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• pp.143-154
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• 1999

Panasonic UD-809P 알비도 중성자 열형광선량계를 팬텀에 장착시켜 원자력발전소에서 중성자 개인선량당량을 측정하였다. 측정된 판독값으로부터 Panasonic 사의 사용자 매뉴얼에 제시되어 있는 방법을 이용하여 열중성자와 초열중성자 및 속중성자로 인한 개인선량당량을 평가하였다. 그 결과 열중성자 성분의 비율이 높은 원자력발전소에서는 속중성자로 인한 개인선량당량을 적절하게 평가할 수 없는 것으로 확인되었는데, 이는 열중성자로 인한 알비도 성분이 열형광선량계로 재입사 되는 양이 이론적인 값과 상당한 차이가 나기 때문인 것으로 추정되었다. 따라서 원자력발전소와 같이 열중성자 성분의 비율이 높은 조건에서 속중성자로 인한 중성자 개인선량당량을 평가하기 위하여 중성자 성분을 열중성자와 속중성자로 구분한 새로운 중성자 선량계산 알고리즘을 제안하였으며, 각각의 성분에 대한 개인선량당량과 교정인자, 민감도 인자 평가공식을 유도하였다.

• Journal of Radiation Protection and Research
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• 제40권3호
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• pp.155-161
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• 2015

Radon is a naturally occurring radioactive gas and a major indoor contribution of exposure to ionizing radiation in dwellings. $^{222}Rn$ is a health hazard gas what is responsible for thousand lung cancer deaths every year. In this study, indoor radon concentrations present in thirty representative houses in Mahallat city, Iran, were determined in order to estimate lung cancer risk associated with residential radon exposure. Long-term passive method, using CR-39, was used to measure the radon concentration. The results showed an association between the age of the dwellings and the indoor radon concentration that was found, in that the concentration of radon tended to increase as the age of the dwelling also increased. The indoor radon concentrations were calculated to be within the range of $23{\pm}2$ to $350{\pm}26Bq{\cdot}m^{-3}$, with an average of $158Bq{\cdot}m^{-3}$. The annual effective dose from inhaled radon and its decay products was calculated between $0.8{\pm}0.1$ and $12.3{\pm}0.9mSv{\cdot}y^{-1}$, with an average of $5.5mSv{\cdot}y^{-1}$. By taking into consideration the EPA recommendation and ICRP statement, the average annual risk of lung cancer from inhaled radon was calculated as 0.09%, 0.06%, 0.01%, and 0.03% for current smokers (CS), those who had ever smoked (ES), never smokers (NS) and the general population, respectively.

• 대한소아치과학회지
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• 제47권1호
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• pp.62-69
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• 2020

이 연구는 치과 핸드피스의 소음 수준과 소음 저감 장치의 효과를 평가하기 위한 것이다. 귀 모형은 치과용 핸드피스 작동 중에 내이에 전달되는 소음의 수준을 측정할 수 있도록 설계되었다. 소음의 크기는 귀 모형과 휴대용 소음 측정기를 사용하여 다양한 조건에서 측정되었다. 시판되는 4종의 소음 저감 장치를 귀 모형에 적용한 후 같은 조건에서 소음 수준을 측정한 뒤 비교하였다. 치과 핸드피스의 소음 수준은 조건에 따라 약 82.5 - 84.4 dB이었다. 4종의 소음 저감 장치를 적용했을 때 소음은 67.4 - 73.8 dB로 감소했다. 4종의 장치 모두 핸드피스의 소음을 줄이는데 유의한 효과가 있었다. 강도와 노출 시간을 고려할 때, 치과 소음은 치과 의료진에게 청력 손상을 일으킬 수 있다. 직업적 청력 손상 위험을 예방하기 위해 소음 저감 장치 사용을 고려할 수 있다.

• Journal of Radiation Protection and Research
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• 제3권1호
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• pp.6-22
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• 1978

High energy electron beams took effect for tumor radio-therapy, however, had a lot of problems in clinical application because of various conversion factors and complication of physical reactions. Therefor, we had experimentally studied the important properties of high energy electron beams from the linear accelerator, LMR-13, installed in Yonsei Cancer Center. The results of experimental studies on the problems in the 8, 10, 12 Mev electron beam therapy were reported as following. 1. On the measurements of the outputs and absorbed doses, the ionization type dosimeters that had calibrated by $^{90}Sr$ standard source were suitable as under 3% errors for high energy electrons to measure, but measuring doses in small field sizes and the regions of rapid fall off dose with ionization chambers were difficult. 2. The electron energy were measured precisely with energy spectrometer consisted of magnet analyzer and tele-control detector and the practical electron energy was calculated under 5% errors by maximum range of high energy electron beam in the water. 3. The correcting factors of perturbated dose distributions owing to radiation field, energy and material of the treatment cone were checked and described systematically and variation of dose distributions due to inhomogeneous tissues and sloping skin surfaces were completely compensated. 4. The electron beams, using the scatterers; ie., gold, tin, copper, lead, aluminium foils, were adequately diffused and minimizing the bremsstrahlung X-ray induced by the electron energy, irradiation field size and material of scatterers, respectively. 5. Inproving of the dose distribution from the methods of pendulum, slit, grid and focusing irradiations, the therapeutic capacity with limited electron energy could be extended.

• 한국환경생태학회지
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• 제12권3호
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• pp.242-252
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• 1998

The inhabitation environments and growth conditions of Machilus thunbergii community in the Pyonsanbando located at southwestern area in Korea were examined and analyzed to provide some practical data to be used to establish measures for long term succession monitoring, protection and sustainable management. The Machilus thunbergii community are located at Kyokpo-ri, Pyonsan-myon, Puan-gun(35$^{\circ}$35′24"N~35$^{\circ}$ 42′30"N, 126$^{\circ}$28′18"E~126$^{\circ}$40′40"E). Within the Pyonsanbando area the mean temperature is 12.4$^{\circ}C$, the warmth index 101.5$^{\circ}C$.month, the coldness index -12.3$^{\circ}C$ month and the annual precipitation 1,016mm. The soil within the community is silt loam or clay loam and so fertile. 30 species and 1 varieties of 21 families inhabited at the community. There were 18 grown trees and 131 saplings of Machilus thunbergii within the community. The mean basal diameter, mean height, and crown width of grown trees was measured to be 57.4cm, 7.4m and 9.0~9.8m respectively. And 9 trees were full flowering, 2 trees small flowering here and there, and 7 trees non flowering in 1998. The mean branch growth length was 8.3cm, mean leaf area 18.3$\textrm{cm}^2$, mean inflorecence length 9.3cm, mean fertilization 14.5％ and mean seed diameter 7.6mm. Further rich management measure and investigation were recommended such as sapling protection, signboard construction, soil erosion controlling and regular monitoring within the community.

• Journal of Radiation Protection and Research
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• 제36권1호
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• pp.35-43
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• 2011

The PHENIX Experiment is the largest of the four experiments that have taken data at the Relativistic Heavy Ion Collider. PHENIX, the Pioneering High Energy Nuclear Interaction eXperiment, is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons. The primary goal of PHENIX is to discover and study a new state of matter called the Quark-Gluon Plasma. Among many particles, muons coming from W-boson decay gives us key information to analyze the spin of proton. Resistive plate chambers are proposed as a suitable solution as a muon trigger because of their fast response and good time resolution, flexibility in signal readout, robustness and the relatively low cost of production. The RPC detectors for upgrade were assembled and their performances were evaluated. The procedure to make the detectors better was optimized and described in detail in this thesis. The code based on ROOT was written and by using this the performance of the detectors made was evaluated, and all of the modules for north muon arm met the criteria and installation at PHENIX completed in November 2009. As RPC detectors that we made showed fast response, capacity of covering wide area with a resonable price and good spatial resolution, this will give the opportunity for applications, such as diagnosis and customs inspection system.

• 동의생리병리학회지
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• 제25권3호
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• pp.482-488
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• 2011

Cadmium (Cd) is well known as a spermatotoxic and gonadotoxic heavy metal ion. This study was performed to assess the possible protective effect of Enerbalance on Cd-induced spermiotoxicity and testicular damage. The control group received isotonic saline; Cd group received Cd (2 mg/kg BW per day) orally; extract-treated groups were orally administrated with Enerbalance (50 mg and 100 mg/kg BW per day) and Cd for 10 days. Morphological changes of testicular tissue, sperm characteristics, oxidative/antioxidative parameters from testis, and serum sexual hormone level were determined. Enerbalance was significantely increased sperm amount in cauda epididymis without changes of ratio of epididymis/body weight and testis/body weight. Cd caused a marked decrease in epididymal sperm concentration and chemotactic sperm motility, testicular superoxide dismutase (SOD), catalase (CAT), Enerbalance was significantly ameliorated loss of epididymal sperm concentration, sperm chemotactic motility, antioxidative parameters, and male hormone whereas decreased abnormal architecture by testis damage. Enerbalance was successfully attenuated these adverse effects of Cd and offers a dose-dependent protection. Our study demonstrated that Enerbalance could proffer a measure of protection against Cd-induced testicular damage and spermiotoxicity by possibly reducing oxidative stress and increasing the antioxidant defense mechanism in mice.

• 한국동물위생학회지
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• 제38권4호
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• pp.253-257
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• 2015

Bull-boxing in South Korea is a form of competitions in which bulls measure their strength with each other in the form of pushing by putting their heads together. Bull-boxing has been admitted after being designated as a play culture by the government because it does not cause great injuries to animals' bodies and has strong positive aspects such as contributing to livestock farmers' leisure activities, encouragement of animal husbandry, and communities' economic development. However, bull-boxing sometimes causes damage to the head and horns due to the heavy bodies. According to the results of examinations of these damage cases, damage that caused irregular shapes of the base of horns was identified in 31.5% of fighting bulls. The damage to horns is thought to have been caused by the great forces of fighting bulls repeatedly imposed to each other's horns during bull-boxing that caused minute fractures leading to damage to the blood vessels inside the horns resulting in the blocking of delivery of nutrients to the horns causing the deformation of the horns into abnormal shapes. Since bulls' bodies are injured during bull-boxing although the injuries are small as bull-boxing is mainly conducted by pushing, animal protection groups regard bull-boxing as cruelty to animals and request to stop bull-boxing. The present study aims to develop animal welfare type headgears that can protect bulls' horns and heads in order to protect fighting bulls during bull-boxing in terms of animal protection and welfare.

• 원예과학기술지
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• 제17권6호
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• pp.773-776
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• 1999

선인장 및 몇 가지 식물이 컴퓨터 모니터로 부터 발생되는 ELF 및 VLF 전자파의 차단효과에 미치는 영향이 조사되었다. 모니터의 정면에서 전자파가 가장 많이 방출되었으며, 차단효과의 검증을 위해 식물과 다른 대상물들은 모니터의 정면 혹은 측면에 두었다. 측정된 모든 식물에서 모니터 발생의 전자파 중 자계 (magnetic waves) 차단에는 전혀 효과적이지 못한 것으로 나타났다. 한편, 선인장의 크기, 형태, 그리고 배치방법에 따라서는 약간의 전계(electric waves) 차단효과가 있는 것으로 나타났으나, 경미하여 TCO의 규정치(electric field: 10V/m and 1V/m in ELF and VLF, respectively)에는 미치지 못하기 때문에 실용화하기에는 어려운 것으로 판단된다.

• Journal of Radiation Protection and Research
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• 제29권4호
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• pp.221-230
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• 2004

방사선작업종사자에게 발생한 암의 방사선 인과도를 평가하기 위한 통계적 측도로 인과확률(Probability of Causation)이 주로 이용된다. 인과확률의 계산 과정에는 다양한 형태의 불확실성이 존재하며, 따라서 인과확률은 하나의 점추정치(point estimate)가 아니라 여러 불확실성을 반영한 분포 또는 신뢰구간으로 평가되어야 한다. 본 연구에서는 국내 방사선작업종사자에게서 발생한 암의 방사선 인과도를 평가하기 위하여, 한국인의 기저자료를 반영하며 가장 최근에 발표된 NCI-CDC 모형에 근거하여 인과확률의 분포를 계산하도록 개발된 전산 프로그램 RHRI-PEPC를 소개한다. 또한 방사선작업종사자의 가상 피폭시나리오에 대한 모의실험을 통해, 인과확률의 점추정치와 불확실성 분포에 의한 방사선 인과도 평가 결과의 차이를 살펴보고 분포에 의한 평가의 경우 적절한 신뢰도 선택의 필요성을 제시한다.