After the major radioactivation structures (RPV, Core, SG, etc.) due to neutron irradiation from the nuclear fuel in the reactor are permanently shut down, numerous nuclides that emit alpha-rays, beta-rays, gamma-rays, etc. exist within the radioactive structures. In this study, nuclides were selected to evaluate the source term for worker exposure management (external exposure) at the time of decommissioning. The selection of nuclides was derived by sequentially considering the four steps. In the first stage, the classification of isotopes of major nuclides generated from the radiation of fission products, neutron-radiated products, coolant-induced corrosion products, and other impurities was considered as a step to select evaluation nuclides in major primary system structures. As a second step, in order to select the major radionuclides to be considered at the time of decommissioning, it is necessary to select the nuclides considering their half-life. Considering this, nuclides that were less than 5 years after permanent suspension were excluded. As a third step, since the purpose of reducing worker exposure during decommissioning is significant, nuclides that emit gamma rays when decaying were selected. As a final step, it is a material made by radiation from the fuel rod of the reactor and is often a fission product found in the event of a Severe accident at a nuclear power plant, and is excluded from the nuclide for evaluation at the time of decommissioning is excluded. The final selected Co-60 is a nuclide that emits high-energy gamma rays and was classified as a major nuclide that affects the reduction of radiation exposure to decommissioning workers. In the future, based on the nuclide selection results derived from this study, we plan to study the evaluation of worker radiation exposure from crud to decommissioning workers by deriving evaluation results of crud and radioactive source terms within the reactor core.

최근 국내에서는 꿀벌 대량소실 현상이 2022년부터 전국적으로 발생하고 있다. 우리나라 뿐 만 아니라, 전세계 적으로 양봉산업에 큰 위협이 되고 있는 봉군붕괴현상은 2016년 미국에서 세계 최초로 보고되었다. 국내에서는 2022년 민관 합동조사 결과, 이상기온, 응애, 말벌 등이 주요 원인으로 지목되었다. 대량소실 현상을 보인 양봉농 가와 정상 농가의 병원체 검출 비교 결과, 유의성있게 검출이 증가되는 병원체는 발견되지 않았다. 그러나, Tyrophagus mite, Trypanosome, Lake Sinai virus, Apis mellifera filamentous virus 등의 신종 응애, 원충 및 바이러 스 감염이 추가로 확인되었다. 국내에서 새롭게 감염이 확인된 기생충과 병원체가 대량소실, 나아가 봉군붕괴현 상에 직간접적으로 영향을 주었을 것으로 사료되며, 지속적인 조사와 연구개발을 통해 기후등 환경변화에 따른 신종 질병 검색과 대책을 마련해야 할 것이다.

Although the proportion of coal-fired power generation is decreasing, efficient operating technology is needed to continuously invest in facilities and reduce maintenance costs until it is abolished. Boilers, one of the main facilities of power plants, operate for a long time in harsh environments of high temperature and high pressure. In addition, damage due to deterioration is likely to occur depending on the fuel and tube material used. It is very important to judge soundness because damage caused by deterioration adversely affects facility operation. Previously, replication method was used to analyze the progress of deterioration. In the replication method, pre-treatment such as chemical treatment is performed on the boiler tube in the field, the area is reproduced by attaching a film, and the replicated film is determined by an expert in the laboratory with an expensive microscope. However, this method involves substantial costs and time requirements, as well as the possibility of human errors. To address these issues, we developed a mobile health assessment system in this research. Since it is detachable and takes images in real time, this system enables swift evaluations across a broad range and facilitates the assessment of preprocessing quality. In addition, it was intended to reduce existing human mistakes by developing a degradation classification algorithm using the merger cluster method.

n Korea, the decommissioning of nuclear power plants is being prepared, and a large amount of radioactive waste is expected to be generated. In particular, clearance level waste, which accounts for more than 90%, requires prevention of cross-contamination and prompt classification. In this study, the possible exposure route and the derivation of exposure dose for worker exposure management in a movable analysis system that can be analyzed onsite were studied. The movable radionuclide analysis system is divided into a preparatory room, a sample storage room, a radioanalysis room, a laboratory, and a waste storage room. It consists of one radioanalysis worker and one pre-treatment worker, and the main radiation exposure is expected to occur in the movement path in the sample storage room, radioanalysis room, and laboratory. The source term for the exposure evaluation, the annual usage dose presented in the radiation safety report in the movable radionuclide analysis system was used. The input data for the evaluation of the external exposure dose under normal circumstances (exposure situation, working hours, distance, etc.) is referenced at facility specifications. The internal exposure dose evaluation was assumed to be acute exposure (1 hour) assumed as internal pollution due to the drop in liquid sample during the pretreatment work. As an evaluation method, a method using a calculation formula and a method using an evaluation code was performed. For the evaluation of exposure dose using the calculation formula, a preliminary evaluation was performed using the point source method, the point kernel method, and intake and dose conversion factors. In addition, VISIPLAN and IMBA codes were used to evaluate exposure dose using the evaluation code, and the input data were supplemented for evaluation. As a result of the evaluation, the annual exposure dose limit of 20 mSv was satisfied for both normal and non-normal situations. In future research, it is planned to derive the evaluation results by particular scenarios for the detailed movement route and evaluation time according to the work process in the mobile radionuclide analysis.

본 논문에서는 각 사용자에게 적합한 게임의 난이도 조절을 위하여 인간의 생리적 반응을 분석하는 방법을 이용하여 객관적이고 정량적인 사용자 반응을 측정하는 방식을 사용하였다. 생리적 신호 측정 방식 중 인간의 인지와 감정을 계량하는데 적합한 뇌파 신호를 측정하고 기존의 연구에서 사용되었던 지표를 이용해 측정한 신호를 분석하였다. 그리고 기존의 다른 분야에서 사용하던 지표를 게임의 난이도에 적합하게 개선하여 기존의 방식을 그대로 사용한 결과와 비교하여 어떤 개선점을 보이는지 확인하였다. 이를 위해 먼저 피험자의 휴식 상 태에서 나타나는 뇌파를 측정하여 기준이 되는 배경 뇌파로 사용하였다. 테트리스에 두 가지 난이도를 설정하고 각각의 난이도를 진행하는 피험자의 뇌파를 측정하였다. 각 난이도에서 측정한 뇌파와 기준이 되는 배경 뇌파의 차이를 각 난이도를 진행할 때 피험자가 보이는 뇌파 반응의 결과로 간주하였다. 이 결과를 기반으로 지금까지 다양한 분야에서 지표로 삼았던 뇌파의 대역별 주파수 변환 결과를 비교 지표로 사용하는 방식과 좌뇌와 우뇌의 비대칭성을 기반으로 긍정, 부정을 파악하는 지표로 사용하는 방식, 알파파와 베타파의 비례 값을 각성, 이완의 지표로 사용하는 방식으로 분석하였다. 마지막으로 세타파를 기준으로 알파파와의 비례 결과와 베타파와의 비례 결과를 각각 몰입과 긴장의 지표로 이용하여 분석하였다.

A combination of Polycarbonate (PC) material and Polymethylmethacrylate (PMMA), fabricated using an injection molding machine, has been investigated to determine its advantages, as studied in Ref. 1). This paper aims to investigate the optimization of PMMA/PC blend for both tensile yield strength and impact strength. Furthermore, interaction effects of process conditions on mechanical properties including tensile yield strength and impact strength of PMMA/PC blend by injection molding process are interpreted in this study. Tensile and impact specimens are designed following ASTM, type V, and are fabricated by injection molding process. The processing conditions such as melt temperature, mold temperature, packing pressure, and cooling time are applied; each factor has three levels. As a result, in comparison with optimization of separated responses, mechanical properties of PMMA/PC are found to decrease when optimizing both tensile and impact strengths simultaneously. The melt temperature is found to be the most significant interaction parameter with the mold temperature and packing pressure. In addition, there is more interaction between the mold temperature and cooling time. This investigation provides a useful understanding of the control of injection molding processing of polymer blends in optical application.

이 연구는 스마트 온실의 온습도 데이터를 수집하고, 그 환 경 요인들 간의 상관관계를 분석하여 스마트 온실 환경관리의 기초자료를 제공하고자 수행되었다. 스마트팜 시스템이 도입된 토경 방식의 OS 온실과 암면 배지경 방식의 KB 온실을 대 상으로 기온, 근권온도, 상대습도의 항목에서 매일 24시간의 데이터를 수집하였고, 이중 최고와 최저, 일평균, 주간 평균, 야간 평균, 일교차의 여섯 가지로 세분하여 정리한 후 두 온실 간의 차이와 기온과 근권온도의 상관관계를 분석하였다. 장미의 생육적온은 주간, 야간, 일교차는 이며, 근권온도는, 습도 는 95% 미만을 유지하는 것이 좋다. 두 온실의 실제 환경과 장미의 적정 환경 조건을 비교했을 때, 주간 기온은 OS 온실 에서 5개월 간, KB 온실에서 7개월 간 적정 수준(24~27˚C)을 유지하였다. 야간 기온은 두 온실 모두 2개월간 적정 수준 (15~18˚C)을 유지하였고, 일교차는 OS 온실에서 6개월간, B 온실은 9개월 간 적정 수준(약 10˚C)에 근접하였다. 근권온도 는 OS 온실에서 10개월, KB 온실에서 5개월간 적정 수준 (20~25˚C)을 유지한 반면, 상대습도는 두 온실 모두 연중 적정 범위 내에 들었다. 기온과 근권온도의 상관관계를 분석한 결 과, OS 온실은 최고 온도, 평균 온도, 주간 온도, 야간온도에 서는 뚜렷한 상관관계를, 최저온도와 일교차에서는 약한 상관 관계를 보였으며, KB 온실에서는 전 영역에서 매우 강한 직선 적 비례 관계를 보였다. 결론적으로 토경재배를 실시하는 OS 온실이 고설식 암면배지경을 실시하는 KB 온실에 비해 근권 온도가 기온의 영향을 덜 받았으며, 완충능력이 높은 토경재 배에서는 기온의 영향을 덜 받는다고 볼 수 있다.

The pitch-based activated carbons were prepared with KOH/KMnO4 as a multiple function activation agent to increase the specific capacitance of a supercapacitor electrode active material. And the porous structure and electrochemical properties of activated carbon were analyzed on varying amounts of KMnO4. KMnO4 was decomposed into K2O, MnO, and O2 at the activation temperature of KOH, and MnO was introduced to activated carbon. K2O/ O2 reacts with a surrounding pitch to generate micropores and forms a pathway that exposes MnO to the outside. It also affects to the specific surface area of activated carbon like KOH chemical activation. The enhanced specific surface area and introduced MnO in activated carbon led to a 28.9% increase in specific capacitance.

Fibrous adsorbents, such as activated carbon fibers (ACF) have acknowledged advantages of rapid adsorption rate and ease of modification compared with granular and powdered adsorbents. Based on the surface modification of lyocell-based ACF, we observed different surface characteristics of ACF samples with variation in the mixing ratio and impregnation time of H3PO4, NaCl, and KMnO4 solution. For an engineering application, we also explored the adsorption characteristics of thusproduced ACF samples onto volatile organic compounds (VOCs). Isothermal adsorption experiments were performed using toluene and benzene as adsorbates. Results indicate that both physical and chemical surface properties have an effect on the adsorption of volatile organic compounds (VOCs).

The present study examined changes in surface shape and pore size observed in carbon black particles isothermally oxidized in an air atmosphere according to their burn-off ratio. Carbon black materials were fed into a horizontal tubular furnace in an air atmosphere when the inside temperature reached 600 °C. Subsequently, while changing the isothermal oxidation time, carbon black samples with different burn-off ratios were obtained, i.e., 10.5, 20.0, 30.4, 41.0, 49.9, 59.8, 71.1, and 81.0%. The scanning electron microscope analysis revealed that the observed carbon black particles were in the form of aggregated primary particles, and that there was no change in the particle size of these primary particles as the burn-off process proceeded. The latter observation supported the observation that pores were formed in the carbon black samples during the burn-off process. Notably, the Brunauer–Emmett–Teller analysis exhibited hysteresis curves, indicating that the corresponding adsorption isotherms were of IV-type. It was also found that the area of the hysteresis curves increased as the burn-off process proceeded. The specific surface area of the raw carbon black sample was 58.00 m2/g, while that of the 81.0% sample was about 4.1 times the figure at 240.27 m2/g. The total pore volume VT was 0.17 cm3/g for the raw sample, and it was much higher for the 81.0% sample at 0.58 cm3/g. The transmission electron microscope analysis showed that the raw carbon black particles had a spherical shape with a smooth surface, but inner pores were not observed. In the 49.9% sample, pores with a size of about 5 nm were observed inside carbon black particles. Notably, the size of the pores observed in the 81.0% sample was about 20 nm and the large pores were created by the collapsing and merging of the smaller pores by oxidation.