The purpose of this study is to provide technical issues in upgrade and modification of fuel handling equipment at operating nuclear power plants. The improvement for safety function and performance enhancement of fuel handling equipment has been going on for 20 years since the early 2000’s. This improvement is recently focused on the replacement of components through the performance analysis and the operation and maintenance plan based on replacement cycle of its component. Additionally, it is required to secure spare parts so that it can be operated at all times with compatibility and standardization to other domestic nuclear power plants. The fuel handling equipment is consisted of refueling machine, upender and carriage of fuel transfer system, spent fuel handling machine, new fuel elevator and various tools, and the equipment are linked in systematic interlocks. Fuel handling is a critical task during a nuclear power plant refueling outage. Even minor component defects may stop operation of the whole system and have a significant impact on the overall system process. To achieve this goal, major components that are expected to be replaced for reliable operation are summarized as follows; 1) motor assembly with AC servomotors and driver for bridge, trolley and hoist of refueling machine and spent fuel handling machine, 2) winch motor and drive for upender and carriage of fuel transfer system, 3) operator control console with a HMI PC base PLC (Programmable Logic Controller) control system, 4) positioning and load weighing sensors such as an encoder and a load cell with its support for periodic calibration and maintenance, 5) main power drapped style festoon cable assembly for bridge of refueling machine, 6) pneumatic control assembly for gripper operation of refueling machine, 7) active components (e. g., air motor, hydraulic cylinder and limit switch) to be removable and reinstallable without requiring the water level to be lowered. It is advisable to utilize such various information as it can help to improve reliability of fuel handling as a critical path in upgrade and modification of fuel handling equipment at operating nuclear power plants.

해양산업분야에서는 극심한 대기오염으로 인하여 전기추진선박에 대한 관심이 높아지고 있다. 이로 인해 선내 전력품질의 저하를 개선하기 위한 연구가 활발히 진행되고 있다. 기존 DFE 정류기의 입력전류 고조파 함유량을 완화시키기 위해 수동형필터, 노치필터, 능동형필터 등을 이용한 다양한 방법이 등장하였다. 그 중에서도 능동필터의 일종인 AFE(Active Front End) 정류장치가 우수한 기술로써 평가받고 있다. 본 논문에서는 공간벡터변조에 의한 AFE정류장치의 전류제어방식을 제안하였다. 기존의 히스테리시스 방식, 삼각파 변조 방식 및 공간벡터변조방식을 PSIM을 사용해 시뮬레이션을 수행하여 비교, 분석하였고, 그 결과 공간벡터변조방식이 구조가 간단하고 성능이 가장 우수함을 확인하였다.

본 논문에서는 12펄스 정류기의 커패시터 중앙 DC버스에 개선된 보조전원장치를 설치하는 방법을 제안하였다. 11차 및 13차 고조파가 감소하는 이론적인 배경을 다루었으며 부하전류의 크기, 전원전압의 위상 및 크기, 커패시터 전압에 따라 개선된 보조전원의 파형 및 크기가 어떻게 제어되어야 하는지를 제시하였다. 기존의 구형파 보조전원장치를 적용한 경우는 전 영역에서 고조파 왜형률이 6~60[%]로 큰 편차를 보이지만 본 눈문에서 제안하는 개선된 보조전원장치를 적용한 경우 저 부하에서 고 부하에 이르는 전 영역에서 57~71[%] 라는 안정되고 뛰어난 고조파 왜형율 저감 효과를 보인다. 특히 10[%] 부하상태에서 기존방식은 고조파 왜형율 저감효과가 6[%]로 효과가 거의 없지만 제안된 방식은 71[%]라는 놀라운 저감성능을 보여주고 있다. 소프트웨어 PSIM을 활용하여 컴퓨터 시뮬레이션을 통해 제안된 방식의 유효성을 입증하였다.

The present study investigated the urinary tract toxicity of melamine alone or in combination with cyanuric acid in rats. Male rats were orally administered melamine alone (800 mg/kg) or melamine plus cyanuric acid (50 mg/kg each) for 3 consecutive days. Although melamine treatment did not show any significant difference in body weight, kid- ney or urinary bladder weight, serum blood urea nitrogen (BUN) or creatinine levels, it caused a decrease in urinary pH and mild histopathological alterations in the kidney and urinary bladder. In contrast, co-administration of melamine and cyanuric acid induced a decrease in body weight, an increase in kidneys and urinary bladder weights, and an elevation in serum BUN and creatinine levels, which were not observed in animals treated with melamine alone. His- topathological examination showed that the incidence and severity of histopathological lesions in the kidney and uri- nary bladder were much higher than those in the melamine group. Urinalysis revealed an increase in urine occult blood, leukocytes and protein and a decrease in urinary pH. These results indicate that concomitant administration of cyanuric acid synergistically potentiated the urinary tract toxicity induced by melamine in rats. In this study, we first demon- strated the synergistic toxic effects of melamine in combina- tion with cyanuric acid on urinary bladder and urinalysis in rats.

본 연구는 영산강하구역 입자물질 유입원의 시∙공간 적인 변화를 추정해 보고자 몽탄대교에서 영산강 하구둑 에 이르는 영산강하구역 세 정점에서 연 6회에 걸쳐 수 층 부유 물질의 탄소 및 질소 안정동위원소 비를 비교하 였다. 모든 정점에서 8월에 강우를 통한 외부기원 유기물 의 유입이 증가하였으며, 이 때 암모니아성 질소 및 규산 염의 유입 역시 함께 증가하였다. 탄소 안정동위원소 비 측정 결과 11월과 8월에 정점 별 유기물의 기원이 크게 차이 났으며, 안정동위원소 비 값을 이용하여 주요 유입 원 추정이 가능하였다. 11월에 모든 정점에서 질소 안정 동위원소 비가 무거운 값을 보였고, 인산염의 농도가 가 장 높게 나타났는데 이는 축산폐수 및 농경지를 통한 유 입이 영향을 준 것으로 판단된다. 또한 다른 정점에 비해 영산강 하구둑에서 모든 조사 기간 동안 비교적 높은 질 소 안정동위원소 비를 보였으며, 이를 통해 축산폐수 및 농경지를 통한 유기물 유입이 다른 정점에 비해 높을 것 으로 추정된다. 본 연구 결과를 통해 안정동위원소 비 분 석은 입자성유기물의 기원을 추정하는데 유용한 방법임 을 확인할 수 있었다.

This study was performed to investigate the anti-obesity and anti-lipidemic ability of linalool (LL) in ApoE deficient mice fed a high-fat diet (HFD). Mice were divided into four experimental groups of eight each. Mice in the control group received a basic diet and oral repeated dose of the vehicle only for 12 weeks; mice in the HFD group received a HFD and oral repeated dose of the vehicle only for 12 weeks; and the HFD&LL25 and HFD&LL50 groups received a HFD and oral repeated dose of LL 25 and 50 mg/kg/day for 12 weeks, respectively. Mice in the HFD group showed a significant increase in body weight, spleen weight, and adipose tissue weight, compared with the control group. An increase in the serum levels of aspartate aminotransferase and alanine aminotransferase activities, total cholesterol (T-CHO), triglyceride (TG), and low density lipoprotein cholesterol was also observed in the HFD group. Histopathological examinations showed severe liver injuries, characterized by extensive fatty changes and hepatocyte degeneration/necrosis. On the contrary, oral administration with LL resulted in significantly improved HFD-induced obesity and hyperlipidemia, indicated by a decrease in adipose tissue weight, T-CHO, TG, and histopathological lesions. The results indicate that LL suppressed HFD-induced obesity, hyperlipidemia, hypercholesterolemia, and hepatic steatosis, suggesting that LL might be a promising adjuvant therapy for treatment of these metabolic disorders related to corpulence.

Coastal dune wetland has an important ecological implication in that it could be closely related to the coastal dune ecosystem by providing various ecological habitats as well as ecological corridor. This paper aims to investigate the hydrological characteristics and aquatic biota of Mokgimiyeonmot (pond), coastal dune wetland in Gulupdo (island). Mokgimiyeonmot located in the lowland dune flat areas has six months long hydro period a year and can be categorized into wet dune slack type coastal dune wetland. As a result of this study, two species of freshwater fishes, two species of amphibia, and 35 species of benthic macro-invertebrates are recognized. Talitridae sp. belonging to Amphipoda also recognized in this survey for the first time from Korea. The results of this study are expected to be basic data necessary to understand the aquatic ecosystems and manage the ecological function of coastal dune field.

This study was conducted in order to evaluate the anti-inflammatory activities of Phellinus linteus (PL) water extract against carrageenan- and cotton pellet-induced acute and chronic inflammation in rats. Animals were divided into four experimental groups for conduct of acute and chronic inflammations studies: the vehicle control group, positive control group (aminopyrine 100 mg/kg), PL 10 mg/kg group, and PL 20 mg/kg group. Oral administration of PL water extract has dose-dependent anti-inflammatory effects against both acute and chronic inflammation models. In carrageenan-induced paw edema, significant inhibition was observed at 0.5 and 1 h in the PL 10 mg/kg group and at 0.5, 1, 2, 3, 4, and 6 h in the PL 20 mg/kg group. In cotton pellet-induced granuolma formation, PL water extract at 10 and 20 mg/kg/day also showed significant inhibition in dry weights of granuloma. Results of the free radical scavenging assay showed that PL has a dose-dependent scavenging activity against 2,2-diphenyl-1-picrylhydrazyl free radicals. The results obtained in this study indicate that this plant material may be used beneficially as an anti-inflammatory agent having antioxidant action.

국제전기기술위원회의 문서 IEC 60601-1의 3판 규격과 IEC 60601-2-45의 개별 규격에서는 진단용 X선 장치에서 X선 피폭 선량 정보를 표시하고 그 정확성을 명시할 것을 권고하고 있다. 하지만 임상에서 사용 하는 부착형 공기커마 면적선량계는 교정에 어려움이 있다. 이에 본 연구에서는 임상에 적용 가능한 RQR 표준 선질을 이용하여 공기커마 면적선량계의 에너지 의존성과 정확도를 평가하였고 임상에서 간접 교정을 시행할 수 있도록 방법론을 마련하고자 하였다. RQR5의 표준 선질에서 시행한 시험에서 부착형 공기커마 면적선량계는 –7.5%의 오차를 나타냈고, RQR8의 표준 선질에서는 –10.3%의 오차를 나타냈으며 시험한 모든 RQR 선질에 대해 평균 절대오차는 8.30%±2.85%를 나타내 IEC 60580과 AAPM TG 190의 조건을 만족하였다. 본 연구에서 도출한 공기커마 면적선량계의 교정 방법은 임상에서 사용하는 공기커마 면적 선량계의 간접 교정법으로 사용할 수 있을 것으로 기대한다.

The cholesterol lowering effect of vegetables fermented by Lactobacillus plantarum HY7712 was evaluated in rats fed high fat/high cholesterol diet. SD Rats were randomly divided into three groups, then fed a normal diet (ND), a highfat high-cholesterol diet (HFCD), or HFCD and vegetables fermented by HY7712 (VFLAB) for 5 weeks, and the biomarkers in the blood, liver, and feces of rats were measured. Antioxidant status such as SOD, CAT, GSH/GSSG, and MDA was significantly deteriorated in HFCD compared with ND (p<0.01) but was improved in VFLAB to the level of ND. In addition, the level of MDA in VFLAB was significantly decreased in comparison with HFCD (p<0.05). Total cholesterol, LDLcholesterol, and atherogenic index (AI) were significantly increased in HFCD, but significantly decreased in VFLAB (p<0.05). In addition, administration of a HFCD diet increased the fecal bile acid in rats and the concentration of fecal bile acid was higher in VFLAB than in HFCD. In conclusion, the vegetables fermented by L. plantarum HY7712 improved antioxidant status and hypercholesterolemia induced by HFCD diet, which may be due to the synergic effect of lactic acid bacteria and fermented vegetables.