• 한국방사선학회논문지
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• 제15권6호
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• pp.795-801
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• 2021

원전 해체 작업장의 요구에 따라 드론 기반 무인 원격 방사선 검출 모듈을 개발하였다. 사람이 접근해서 방사선을 측정할 수 없는 원자력 발전소 격납용기 내부 상공 및 외부로 누설되는 방사선 측정을 위한 목적으로 저준위에 민감한 GM-tube를 사용하여 제작하였다. 드론 기반 방사선 검출 모듈의 무게는 200g 미만으로 원자력 발전소 격납용기 내부의 상공과 외부 공중에서도 운용이 가능하다. 설계된 장비의 성능 확인을 위해 국제 기준 (IEC60864)을 참고하여 성능평가 실험을 시행하였다. 현장의 요구에 맞게 설계된 방사선 검출 모듈의 안정성은 측정 정확도를 평가하기 위한 변동률 실험에서 반복 측정에 의한 통계적 변동률은 ±4.6%. 선량률 의존성을 평가하기 위한 선형성 실험에서 정확도 ± 7.3%, 전체 선형도는 ± 3.5%이며 성능평가를 위한 국제기준을 만족하였다. 본 연구에서 개발한 무인 원격 방사선 검출 모듈은 원전 해체 작업장 맞춤형 장비로, 방사선 분진이 많은 현장에서 정확한 공간선량률의 측정과 방사선 작업장 안전관리에 도움을 줄 수 있을 것으로 확신한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.165-168
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• 2008

The experimental results of exposing IGBT (Insulated Gate Bipolar Transistor) samples to gamma radiation source show shifting of threshold voltages in the MOSFET and degradation of carrier mobility and current gains. At low total dose rate, the shift of threshold voltage is the major contribution of current increases, but for more than some total dose, the current is increased because of the current gain degradation occurred in the vertical PNP at the output of the IGBTs. In the paper, the collector current characteristics as a function of gate emitter voltage (VGE) curves are tested and analyzed with the model considering the radiation damage on the devices for gate bias and different dose. In addition, the model parameters between simulations and experiments are found and studied.

• Journal of Plant Biology
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• 제7권4호
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• pp.9-14
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• 1964

According to the results measured the respiratory quotient of Saccharomyces cerevisiae with neutron radiation by manometric direct method, the respiratory quotient of them was stimulated at the dose(7$\times$106N/$\textrm{cm}^2$/sec) of neutron radiation for 60 seconds, and was inhibited in each group irradiated at the high dose (7$\times$108N/$\textrm{cm}^2$/sec) of neutron. Its physiological effects influenced on neutron had relations with respiratory quotient, reproductive rate and fermentation in the curve of normal logarithmic phase. The multiple reactions which appeared in yeast, indicated that a great deal of physiological function were closely correlated with the irradiated dosage of neutron. The kinds of free amino acid in yeast irradiated with neutron were different from those of unirradiated yeast. The activityof dehydrogenase system accelerated the metabolic function of yeast irradiated at some low dose of neutron. By this results, it may demonstrate that the fact which the phenomena obtained in the stimulation of neutron possess its character for several generation, is dependent on the theory of mutation. Subsequently, it seemed reasonable certain dominant type of microorganisms.

• Nuclear Engineering and Technology
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• 제56권7호
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• pp.2516-2523
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• 2024

This study aims to validate the dosimetric characteristics of Low Dose Rate (LDR) I-125 source Geant4-based Monte Carlo code. According to the recommendation of the American Association of Physicists in Medicine (AAPM) task group report (TG-43), the dosimetric parameters of a new brachytherapy source should be verified either experimentally or theoretically before clinical procedures. The simulation studies are very important since this procedure delivers a high dose of radiation to the tumor with only a minimal dose affecting the surrounding tissues. GEANT4 Monte Carlo simulation toolkit associated brachytherapy example was modified, adapted and several updated techniques have been developed to facilitate and smooth radiotherapy techniques. The great concordance of the current study results with the consensus data and with the results of other MC based studies is promising. It implies that Geant4-based Monte Carlo simulation has the potential to be used as a reliable and standard simulation code in the field of brachytherapy for verification and treatment planning purposes.

• 한국환경농학회지
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• 제18권1호
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• pp.66-69
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• 1999

대두작물의 생육에 대한 방사선 hormesis를 구명하고자 세 품종의 콩종자를 저선량 ${\gamma}$선을 조사하여 포장에서 시험하였다. 생육에 대한 저선량 ${\gamma}$선의 자극효과는 품종에 따라서 다른 반응을 보였는데, 백태인 황금콩과 방사콩보다도 흑태인 S900 품종에서 더욱 효과적이었다. 포장발아율은 S900 품종의 0.5Gy 조사구에서 30%정도, 경장에서는 방사콩과 S900 품종의 4.0G 조사구에서 15%정도 증가하였다. 꼬투리수와 종자 수량에서는 황금콩은 2.0G 조사구에서 35%정도, S900 품종은 4.0Gy 조사구에서 25% 정도 증가하였다.

• Clinical and Experimental Reproductive Medicine
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• 제39권4호
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• pp.144-152
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• 2012

Objective: Concerns are growing about the decrease in male reproductive health. Caffeine is one of the popular nutrients that has been implicated as a risk factor for infertility. In the present study, we examined whether in utero and lactational exposure to caffeine affects the reproductive function of the offspring of rats. Methods: Pregnant rats received caffeine via drinking water during gestation (26 and 45 mg/kg) and lactation (25 and 35 mg/kg). Body and reproductive organ weight, seminiferous tubule diameter, germinal epithelium height, sperm parameters, fertility rate, number of implantations, and testosterone level of the offspring were assessed from birth to adulthood. Results: Significant dose-related decreases were observed in the body and reproductive organ weight, seminiferous tubule diameter, and germinal epithelium height of the offspring. Sperm density had declined significantly in offspring of the low-dose and high-dose groups, by 8.81% and 19.97%, respectively, by postnatal day 150. The number of viable fetuses had decreased significantly in females mated with male offspring of the high-dose group at postnatal days 60, 90, 120, and 150. There were also significant reductions in testosterone levels of high-dose group offspring from birth to postnatal day 150. Conclusion: It is concluded that maternal caffeine consumption impairs gonadal development and has long-term adverse effects on the reproductive efficiency of male offspring rats.

• 방사성폐기물학회지
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• 제18권4호
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• pp.537-548
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• 2020

Currently, radioactive waste for disposal has been restricted to low and intermediate level radioactive waste generated during operation of nuclear power plants, and these radioactive wastes were managed and disposed of the 200 L and 320 L of steel drums. However, it is expected that it will be difficult to manage a large amount of decommissioning waste of the Kori unit 1 with the existing drums and transportation containers. Accordingly, the KORAD is currently developing various and large-sized containers for packaging, transportation, and disposal of decommissioning waste. In this study, the radiation exposure doses of workers and the public were evaluated using RADTRAN computational analysis code in case of the domestic on-road transportation of new package and transportation containers under development. The results were compared with the domestic annual dose limit. In addition, the sensitivity of the expected exposure dose according to the change in the leakage rate of radionuclides in the waste packaging was evaluated. As a result of the evaluation, it was confirmed that the exposure dose under normal and accident condition was less than the domestic annual exposure dose limit. However, in the case of a number of loading and unloading operations, working systems should be prepared to reduce the exposure of workers.

• 대한디지털의료영상학회논문지
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• 제15권2호
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• pp.39-44
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• 2013

Purpose : The purpose of this study is the magnification rates depending on the area of patient dose (DAP) and glass dosimeter see the change of the dose according to the dose characteristics of low-magnification aims to raise standards. Materials and Method : Direct DR equipment Sonialvision DAR-8000f, Shimadzu was used, the patient entrance dose measurements to the surface of the Rando Phantom of the neck and the abdomen was placed on the Xi unfors. glass dosimeter for measuring organ doses at the same time the Rando Phantom of the major organs in place by inserting a 9 ", 12", 15 ", 17" and 30 seconds for each magnification were measured according in fluoroscopy. DAP meter area of the patient dose was measured. Result : Esophagography at 17" 143% than 9"magnification the average area dose was increased. Organ dose of Esophagography at 17" was decreased 25.32% than 9" magnification. UGI at 17" was increased 129.73% DAP than 9" magnification. Organ dose of UGI at 17" was decreased 23.32% than 9" magnification. Where the major organs of magnification at 17" were decreased(lung -25.96%, stomach -33.09%, spleen -27.81%, liver -4.92%) than 9" magnification. Conclusion : Expected to get better quality image While using the proper magnification, and have recognition that difference Organ doses and DAP meter in fluoroscopy.

• Asian Pacific Journal of Cancer Prevention
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• 제13권9호
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• pp.4757-4761
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• 2012

Objectives: To explore the impact of low- vs conventional-dose chemotherapy via transcatheter arterial chemo-embolization (TACE) on serum fibrosis indicators and treatment efficacy of hepatocellular cancer patients (HCC). Materials and Methods: Patients fulfilling the eligibility criteria were assigned to TACE in Group A (with low-dose chemotherapy) or Group B (conventional-dose chemotherapy). Four serum fibrosis related indicators, hyaluronic acid(HA), human pro-collagen type-III (hPC-III), laminin (LN), and collagen type-IV(IV-C) before TACE were compared with the values 7 days after TACE. The response rate and survival time were also compared between the two groups. Results: Fifty patients with HCC were enrolled in this study, including 25 in Group A and 25 in Group B. No significant differences were detected between the two groups in the four indicators before TACE. After TACE, the value of the four serum indicators increased significantly in Group B. However, no significant differences regarding these four indicators were found in Group A after TACE. Significant differences were demonstrated between the two groups after TACE, but median survival time and 1 or 2 year overall survival rates did not differ (P>0.05). Conclusions: Low-, compared with conventional-dose chemotherapy exerts the same impact on the variation of fibrosis related indicators and has no influence on median survival time and survival rate after TACE in HCC patients.

• 한국환경농학회지
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• 제24권2호
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• pp.153-158
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• 2005

염 스트레스 하에서 벼 생육에 대한 저선량 방사선의 경감효과를 확인하기 위해 일품벼와 간척벼 두 품종에 저선량 감마선을 0-32 Gy 수준으로 조사하였다. 염 처리에 따른 생장반응은 무 처리구에 비해 두 품종 모두 염 처리구에서 생육이 감소하였으며, 초장과 생체중보다 건물중에서 더 많은 감소를 보였다. 이외에도 초기건량에 대한 단위시간당 건물의 증가를 나타내는 상대생장율을 관찰한 결과, 전체 상대생장율이 염 처리구에서 50% 이상 억제되었다. 그러나 이러한 생육억제는 저선량 방사선에 의해 경감됨을 확인할 수 있었다. 특히, 줄기 상대생장율의 경우 염 처리시 4 Gy 조사구가 대조구보다 30% 이상의 경감효과를 보였다. 또한 염 스트레스에 대한 조직의 막투과성 정도는 염 처리에 의해 4배 정도 피해를 보였으나 4 Gy 조사구에서 10% 이상의 경감효과를 보였으며, 상대수분함량도 30% 정도의 감소를 보인 염 처리구에서 저선량 방사선의 효과를 확인 할 수 있었다. 이러한 결과를 통해, 저선량 방사선이 염 스트레스에 대한 저해 효과를 경감시키는 것으로 사료된다.