• Nuclear Engineering and Technology
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• 제40권7호
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• pp.539-550
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• 2008

Lung cancer is the most prevalent global cancer, ${\sim}90%$ of which is caused by cigarette smoking. The LNT hypothesis has been inappropriately applied to estimate lung cancer risk due to ionizing radiation. A threshold of ${\sim}1\;Gy$ for lung cancer has been observed in never smokers. Lung cancer risk among nuclear workers, radiologists and diagnostically exposed patients was typically reduced by ${\sim}40%$ following exposure to <100 mSv low LET radiation. The consistency and magnitude of reduced lung cancer in nuclear workers and occurrence of reduced lung cancer in exposed non-worker populations could not be explained by the HWE. Ecologic studies of indoor radon showed highly significant reductions in lung cancer risk. A similar reduction in lung cancer was seen in a recent well designed case-control study of indoor radon, indicating that exposure to radon at the EPA action level is associated with a decrease of ${\sim}60%$ in lung cancer. A cumulative whole-body dose of ${\sim}1\;Gy$ gamma rays is associated with a marked decrease in smoking-induced lung cancer in plutonium workers. Low dose, low LET radiation appears to increase apoptosis mediated removal of $\alpha$-particle and cigarette smoke transformed pulmonary cells before they can develop into lung cancer.

• Journal of Radiation Protection and Research
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• 제6권1호
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• pp.1-7
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• 1981

This report presents the results of the environmental radiation program at Korea Advanced Energy Research Institute (KAERI) ($37^{\circ}38'N,\;127^{\circ}05'E$) and its surroundings for the last two decades (January, 1961 through December, 1980). In the 1960s, the monthly mean levels of environmental external radiation encountered ranged from a low of 14.2 microroentgen per hour to a high of 42.2 microroentgen per hour with a mean of 21.7 microroentgen per hour, while in 1970s it ranged from a low of 12.4 microroentgen per hour to a high of 40.8 microroentgen per hour with a mean of 20.4 microroentgen per hour. It may, therefore, be said that environmental radiation dose rates remained almost unchanged for the two decades except for the second half of 1960s and the first half of 1970s during which the off-site and on-site patterns were frequently unlike in form and intensity with appreciable differences between average values. Particular results of interest with respect to the effects of the fallout gamma dose rate on environmental radiation show that elevated levels were encountered in association with the deposits of fresh debris from Chinese and Russian nuclear weapons tests in particular.

• 대한방사선기술학회지:방사선기술과학
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• 제46권1호
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• pp.53-61
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• 2023

The aim of this study analyzed the important level (IL) and understanding level (UL) including the Borich's need for students preparing of the national examination for radiological technologists at online open chatting room. A total of 254 survey were collected from a total of 1,016 students who used open chatting room from December 13 to December 16, 2022. A general characteristics were the age, gender, curriculum (3 or 4 years), grade and area. The IL, UL, learning satisfaction (LS), learning achievement (LA) and intention to continue using (ICU) were analyzed by using the 5 point Likert scale. There was no significant difference the LS, LA, and ICU according to general characteristics (p>0.05). There was a statistically significant difference a total of sixteen subjects based on the t-test results of the response values from the IL and UL (p<0.05). The total of ten subjects with the highest priority in the Locus for Focus models were the Ultrasonography, Human anatomy, Magnetic resonance imaging, Radiation therapy, Cardiovascular and intervention, Computed tomography, Human physiology, Radiographic imaging, Fluroscopic radiography, and Nuclear medicine) that the Borich's need was also the same as the top 10 ranked subjects. The LS (4.23±0.72), LA (4.18±0.73), and ICU (4.15±0.78) for open chatting room were high. This study identified the subjects most needed by college students by the Borich's need analysis. First, it is necessary to provide intensive education on subjects with high scores that are most needed by college students. Second, it is necessary to improve the teaching method for subjects with low need and low level of understanding.

• Environmental Analysis Health and Toxicology
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• 제31권
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• pp.1.1-1.13
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• 2016

Objectives To investigate the accuracy and scientific validity of the current very low risk factor for hereditary diseases in humans following exposures to ionizing radiation adopted by the United Nations Scientific Committee on the Effects of Atomic Radiation and the International Commission on Radiological Protection. The value is based on experiments on mice due to reportedly absent effects in the Japanese atomic bomb (A-bomb) survivors. Methods To review the published evidence for heritable effects after ionising radiation exposures particularly, but not restricted to, populations exposed to contamination from the Chernobyl accident and from atmospheric nuclear test fallout. To make a compilation of findings about early deaths, congenital malformations, Down's syndrome, cancer and other genetic effects observed in humans after the exposure of the parents. To also examine more closely the evidence from the Japanese A-bomb epidemiology and discuss its scientific validity. Results Nearly all types of hereditary defects were found at doses as low as one to 10 mSv. We discuss the clash between the current risk model and these observations on the basis of biological mechanism and assumptions about linear relationships between dose and effect in neonatal and foetal epidemiology. The evidence supports a dose response relationship which is non-linear and is either biphasic or supralinear (hogs-back) and largely either saturates or falls above 10 mSv. Conclusions We conclude that the current risk model for heritable effects of radiation is unsafe. The dose response relationship is non-linear with the greatest effects at the lowest doses. Using Chernobyl data we derive an excess relative risk for all malformations of 1.0 per 10 mSv cumulative dose. The safety of the Japanese A-bomb epidemiology is argued to be both scientifically and philosophically questionable owing to errors in the choice of control groups, omission of internal exposure effects and assumptions about linear dose response.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.4137-4141
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• 2021

As NPPs continue to operate, liquid waste continues to be generated, and containers are needed to store and transport them at low cost and high capacity. To transport and store liquid phase very low-level radioactive waste (VLLW), a container is designed by considering related regulations. The design was constructed based on the existing container design, which easily transports and stores liquid waste. The radiation shielding calculation was performed according to the composition change of barium sulfate (BaSO₄) using the Monte Carlo N-Particle (MCNP) code. High-density polyethylene (HDPE) without mixing the additional BaSO₄, represented the maximum dose of 1.03 mSv/hr (<2 mSv/hr) and 0.048 mSv/hr (<0.1 mSv/hr) at the surface of the inner container and at 2 m away from the surface, respectively, for a 10 Bq/g of ⁶⁰Co source. It was confirmed that the dose from the inner container with the VLLW content satisfied the domestic dose standard both on the surface of the container and 2 m from the surface. Although it satisfies the dose standard without adding BaSO₄, a shielding material, the inner container was designed with BaSO₄ added to increase radiation safety.

• Journal of Astronomy and Space Sciences
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• 제37권4호
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• pp.249-255
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• 2020

We develop the tissue-equivalent proportional counter (TEPC) type's space radiation dosimeter to measure in-situ aviation radiation. That was originally developed as a payload of small satellite in the low-earth orbit. This dosimeter is based on a TEPC. It is made of an A-150 tissue-equivalent plastic shell of an internal diameter of 6 cm and a thickness of 0.3 cm. TEPC is filled with pure propane at 13.9 torrs to simulate a cell diameter of 2 ㎛. And the associated portable and low power electronics are also implemented. The verification experiments have been performed by the calibration experiments at ground level and compared with Liulin observation at aircraft altitude during the flight between Incheon airport (ICN) and John F. Kennedy airport (JFK). We found that the TEPC dosimeter can be used as a monitor for space radiation dosimeter at aviation altitude based on the verification with Liulin observation.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.674-680
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• 2022

In the present study, radiation shielding and protection ability of prepared Flyash-lime-Gypsum (FaLG) bricks has been studied in terms of energy exposure build up factors and dose parameters. The energy exposure build up factors of Flyash-lime-Gypsum (FaLG) bricks have been calculated for the energy range of 0.015 MeV-15 MeV and for penetration depth upto 40 mfp directly using a new and simplified Piecewise Linear Spline Interpolation Method (PLSIM). In this new method, the calculations of G.P fitting parameters are not required. The verification and accuracy of this new method has been checked by comparing the results of exposure build up factor for NBS concrete calculated using present method with the results obtained by using G.P fitting method. Further, the relative dose distribution and reduced exposure dose rate for various radioactive isotopes without any shielding material and with Flyash-lime-Gypsum (FaLG) bricks have been calculated in the energy range of 59.59-1332 keV. On the basis of the obtained results, it has been reported that the prepared Flyash-lime-Gypsum (FaLG) bricks possess satisfactory radiation shielding properties and can be used as environmentally safe storage facilities for low level nuclear waste.

• Journal of Radiation Protection and Research
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• 제36권4호
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• pp.230-236
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• 2011

방사선이용의 사회적 수용성 제고 방안의 일환으로 일반대중 가운데 장기적인 관점에서 여론의 주도층 역할을 하게 될 대학생을 대상으로 전공자와 비전공자 사이에 방사선이용 분야별 필요성 인식 차이를 파악하여 방사선이용에 대한 국민이해 증진사업의 효율적인 전략구상에 필요한 근거자료를 제공하고자 한다. 2010년 11월 교육통계서비스(http://cesi.kedi.re.kr) 기준, 전국 4년제 대학교 177개교, 전문대학 146개교 중 전체 24.0%에 해당하는 78개교의 재학생을 표본으로 선정하여 방사선이용 분야별 필요성 인식수준을 설문조사 하였다. 그 결과 전공자와 비전공자 모두 의료분야의 필요성 인식수준이 높았고, 전공자와 비전공자 모두 농업분야의 필요성 인식수준이 가장 낮게 나타났다. 6개 방사선이용 분야 모두 전공자가 비전공자보다 필요성 인식수준을 높게 나타냈다. 각 분야별로 남학생, 의료방사선 경험이 있는 경우, 관련 교육을 받은 경우에 필요성 인식수준이 높았다. 이는 여학생, 의료방사선 경험이 없는 경우, 관련 교육경험이 없는 경우에 대해서는 보다 다양한 정보제공으로 필요성 인식 수준을 상대적으로 더 높일 필요가 있다고 본다. 각 지역별, 방사선이용 분야별 정책결정에 있어서 본 연구결과에 나타난 집단의 특성을 고려한다면 방사선이용에 대한 국민이해 증진사업을 효율적으로 달성하는데 도움이 될 것이라고 사료된다.

• 한국철도학회논문집
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• 제5권1호
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• pp.26-31
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• 2002

The more sophisticated patterns of propagation model is presented in this paper, which includes three different source characteristics (spherical, cosine and dipole). The spherical, cosine and dipole radiation characteristics compared, and sound event level and the maximum sound level are calculated by experiment and calculation. It is shown that patterns of propagation have dipole characteristics for low speed range (below about 150Km/h) at electric multiple system. We know that push-pull high speed system has cosine characteristics of noise propagation at low speed range (below about 200Km/h).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.204-209
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• 2001

The more sophisticated patterns of propagation model is presented in this paper, which includes three different source characteristics (spherical, cosine and dipole). The spherical, cosine and dipole radiation characteristics compared, and sound event level and the maximum sound level are calculated by experiment and calculation. It is shown that patterns of propagation have dipole characteristics for low speed range (below about 150Km/h) at electric multiple system. We know that push-pull high speed system has cosine characteristics of noise propagation at low speed range (below about 200Km/h).