Gd-doped UO₂의 상분리 및 UO₂에 고용된 Gd 함량 측정

김건식,양재호,송근우,김길무 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.9

The change of structure and morphology in ( $U_{0.913}$G $d_{0.087}$) $O_2$ during oxidation at 475$^{\circ}C$ and heat treatment at 130$0^{\circ}C$ in air were investigated using XRD, SEM, and EPMA. The ( $U_{0.913}$G $d_{0.087}$) $O_2$ cubic phase converted to ( $U_{0.913}$G $d_{0.087}$)$_3$ $O_{8}$ orthorhombic phase by oxidation at 475$^{\circ}C$ in air. The XRD and EPMA result of the 130$0^{\circ}C$ heat treated powder revealed that ( $U_{0.913}$G $d_{0.087}$)$_3$ $O_{8}$ orthorhombic phase was separated into $U_3$ $O_{8}$ and ( $U_{0.67}$G $d_{0.33}$) $O_{2+}$x/ cubic phase. The weight variations of (U,Gd) $O_2$ with various Gd contents were measured using TGA at the same heat treated condition. The weight variation during the heat treatment of Gd dissolve (U,Gd) $O_2$ in air can be expressed in terms of phase reaction equations related with oxidation and phase separation. Based on these phase reaction, a initial content of Gd dissolved in (U,Gd) $O_2$ can be exactly calculated by measuring the weight change during the heat treatment. 무게 비로 6%의 Gd가 치환된 이산화 우라늄, ( $U_{0.913}$G $d_{0.087}$) $O_2$를 475$^{\circ}C$ 공기 분위기에서 산화시키고 130$0^{\circ}C$ 공기 분위기에서 열처리시킬 때 변화하는 결정 구조, 형상 등을 XRD, SEM 및 EPMA 등을 이용하여 관찰하였다. 입방계 구조의 ( $U_{0.913}$G $d_{0.087}$) $O_2$는 475$^{\circ}C$ 공기 분위기에서 사방정게 구조의 ( $U_{0.913}$G $d_{0.087}$)$_3$ $O_{8}$로 산화되었다. 저온 산화에 의해 생성된 사방정계 130$0^{\circ}C$의 고온에서 열처리하는 동안 사방정계 상과 압방정계 상으로 다시 분리되었다. XRD와 EPMA 관찰결과, 분리된 사방정계 상과 입방정계 상은 각각 $U_3$ $O_{8}$과 ( $U_{0.67}$G $d_{0.33}$) $O_{2+}$x/인 것을 확인하였다. 열처리 동안 일어나는 일련의 산화와 상 분리 과정은 상 반응식으로 나타낼 수 있다. 각 열처리 단계에서의 무게 변화비를 측정하고 상 반응식을 이용하면 (U,Gd) $O_2$에 고용되어 있는 초기 Gd 함량을 정확히 계산할 수 있다.

Characteristics of Mercury Emission in Vapor Phase from U-type Lamp

( Jae-kyung Kim ),( Hun-su Park ),( Min-seok Lee ),( Seung-whee Rhee ) 한국폐기물자원순환학회(구 한국폐기물학회) 2014 한국폐기물자원순환학회 심포지움 Vol.2014 No.1

After recycling demonstration of spent fluorescent lamp in the area of Seoul Metropolitan, spent fluorescent lamp in Korea was applied by EPR (Extended Producer Responsibility) system from 2004. U-type lamps are also included in EPR system to manage separately from other wastes because U-type lamps contain mercury. Among spent fluorescent lamps, U-type lamps have mainly been generated from household and offices because they are used in electric stand on desk or are used easily for outdoor-lamps powered by dry-cells or batteries. U-type lamp can be also called as parallel lamp or fluorescent U-type lamp(FUL). According to Korea Lighting Recycling Association, approximately 44million U-type lamps were generated and 11 million U-type lamps were recycled in Korea, 2011. Although manufacturers have greatly reduced the amount of mercury used in fluorescent U-type lamps, it is hard to estimate the amount of mercury in U-type lamp. U-type lamps of 36W from 3 companies were used as teat samples in the experiment. The concentration of mercury is analyzed by MVI (Mercury Vapor Indicator) method in vapor phase from U-type lamp. U-type lamp can be crushed once by the crushing process. While the crushing process is operated, mercury vapor can be emitted from the crushing equipment. In the experiment, U-type lamp was crushed in the closed system. Mercury emission from the closed system of U-type lamp is estimated with the airflow rate and time in vapor phase. The initial mercury concentration in vapor phase in the closed system was more than 3,500ppm at airflow rate of 0.7 L/min even though the mercury concentration in vapor phase can be changed by the type of company and period of usage. From the experimental results for U-type lamp, mercury vapor from U-type lamp should be controlled by proper process because the concentration of mercury in vapor phase is much higher than the regulatory level.

산화우라늄의 결정구조 분석

김정석,최용남,이창희,김시향,이영우 한국세라믹학회 2001 한국세라믹학회지 Vol.38 No.11

$UO_2$계 핵연료재료에서 O/U 비가 2.0, 2.03, 2.14, 2.19, 2.20 및 2.26인 시료들에 대한 중성자회절 데이터를 rietveld 정밀화를 이용하여 결함 및 결정구조, 온도에 따른(상온~100$0^{\circ}C$) 상변화 등을 분석하였고, 이를 상태도와 비교하였다. O/U 비가 2.14, 2.19, 2.20인 시료는 모두 $UO_{2+x}$와 $U_4$$O_{9}$ 두 상이 혼합된 것으로 분석되었고, 온도가 증가함에 따라 $UO_{2+x}$의 양이 증가하였다. $UO_{2+x}$는 공간군 Fm3m(a≒5.4$\AA$)으로, $U_4$$O_{9}$은 143d(a≒21.8$\AA$)로 분석되었다. $UO_{2.2}$와 $UO_{2.18}$에서 중성자회절 데이터를 이용한 온도에 따른 상분석 결과와 상태도로부터 예측되는 변화 경향은 대체로 일치하였으나, 부분적으로 차이를 나타내었다. 문헌에서 보고된 $U_4$$O_{9}$상의 ${\gamma}$$\longrightarrow$$\beta$$\longrightarrow$$\alpha$로의 상전이를 상분해와 연관하여 고찰하였다.고찰하였다.하였다.다.하였다. The crystal and defect structures of U $O_{x}$(x=2.0, 2.03, 2.14, 2.19, 2.20 and 2.26) were analysed by rietveld refinement and the results were compared to the U-O phase diagram. Neutron diffraction data were collected in the temperature range of RT~100$0^{\circ}C$. The specimens of x=2.14, 2.19, and 2.20 consisted of two phase: $UO_{2+x}$(Fm3m, a≒5.4$\AA$) and $U_4$$O_{9}$(I43d, a≒21.8$\AA$). The proportion of the $UO_{2+x}$(Fm3m) phase increased with increasing the temperature. The variation of the proportion of the two phases with temperature in the U $O_{2.2}$ and U $O_{2.18}$ samples showed some deviation from the expected values from the phase diagram especially at the high temperature range. The phase transitions ${\gamma}$longrightarrow$\beta$longrightarrow$\alpha$ of $U_4$$O_{9}$ were discussed in relation with the phase separation.eparation.ion.

미국의 재균형 전략과 한미동맹: 신현실주의 패권축소론의 관점에서

이수형 경남대학교 극동문제연구소 2015 한국과 국제정치 Vol.31 No.2

The purpose of this paper is to review the U.S. rebalancing strategy toward the Asia-Pacific from the perspective of neorealist hegemonic retrenchment and its impact on the U.S.-China relations as well as ROK-U.S. alliance. The Obama administration announced that the U.S. would be expanding and intensifying its already significant role in the Asia-Pacific. To do this, the U.S. has adopted rebalancing strategy or the pivot strategy to Asia. One of the most important components of this strategy is to deepen and revitalize the U.S. bilateral security alliances in this region. Faced with the erosion of its relative power, the U.S. would respond rising China and continue to sustain its status and role in the region through rebalancing strategy. Therefore, the most important determinant of the strategy's success is that extent to which China can accept Washington's assurances that a permanent U.S. presence and influence in the Asia-Pacific has broader and positive economic and diplomatic ramifications than merely reinforcing military approach and alliances. The China's perception and response to the U.S. rebalancing strategy however is more skeptical with various analysts in that country often arguing that the U.S. rebalancing strategy is merely an updated version of the Cold War containment strategy directly against China. From a ROK's perspective, it seems that U.S. rebalancing strategy would affect the way of developing ROK-U.S. alliance and the ROK-China relations. Therefore, ROK needs to pursue the limited hedging strategy to overcome difficult challenges derived from competitive U.S.-China relations. That is because ROK has established separate trilateral mechanisms with the U.S. and China respectively and continue to integrate economically with China even as ROK has strengthened its security alliance with the U.S.

전기 정전용량을 기반으로 U-net 모델을 이용한 반도체후단 공정의 잔류물 모니터링

전민호,아닐쿠바,김경연 한국전기전자학회 2024 전기전자학회논문지 Vol.28 No.2

본 논문에서는, 시뮬레이션 상에서 반도체 후단 공정의 프로세스를 구현하고 파이프 내부 상황을 모니터링하기 위해 전기 정전용량을 기반으로 한 U-net 모델을 적용하였다. 배관에 부착된 전극에서 측정한 정전용량 값은 U-net 네트워크 모델의 입력 데이터로사용되며, 모델을 통해 추정한 유전율 분포를 가지고 파이프 단면을 이미지화하였다. 성능 평가를 위해 수치 시뮬레이션 얀에서U-net 모델, FCNN(Fully-connected neural network) 모델, Newton-Raphson 방법으로 재구성한 이미지를 비교한 결과,U-net이 다른 이미지 복원 방식보다 좋은 복원 성능을 보였다. In this study, U-net model based on electrical capacitance is applied to monitor the condition inside thepipeline of semiconductor rear end process implemented in the numerical simulation. Capacitance values measuredfrom electrodes attached to the pipeline is used as input data for the U-net network model and estimated permittivitydistribution by the U-net model is used to reconstructed cross-sectional image at the pipeline. In the numericalsimulation, images reconstructed by U-net model, Fully-connected neural network (FCNN) model and Newton-Raphson method are compared for evaluation. U-net model shows good results as compared to other models.

전기 정전용량을 기반으로 U-net 모델을 이용한 반도체 후단 공정의 잔류물 모니터링

전민호(Minho JEON),아닐쿠마(Anil Kumar Khambampati),김경연(Kyung-Youn Kim) 한국전기전자학회 2024 전기전자학회논문지 Vol.28 No.2

본 논문에서는, 시뮬레이션 상에서 반도체 후단 공정의 프로세스를 구현하고 파이프 내부 상황을 모니터링하기 위해 전기 정전용량을 기반으로 한 U-net 모델을 적용하였다. 배관에 부착된 전극에서 측정한 정전용량 값은 U-net 네트워크 모델의 입력 데이터로 사용되며, 모델을 통해 추정한 유전율 분포를 가지고 파이프 단면을 이미지화하였다. 성능 평가를 위해 수치 시뮬레이션 얀에서 U-net 모델, FCNN(Fully-connected neural network) 모델, Newton-Raphson 방법으로 재구성한 이미지를 비교한 결과, U-net이 다른 이미지 복원 방식보다 좋은 복원 성능을 보였다. In this study, U-net model based on electrical capacitance is applied to monitor the condition inside the pipeline of semiconductor rear end process implemented in the numerical simulation. Capacitance values measured from electrodes attached to the pipeline is used as input data for the U-net network model and estimated permittivity distribution by the U-net model is used to reconstructed cross-sectional image at the pipeline. In the numerical simulation, images reconstructed by U-net model, Fully-connected neural network (FCNN) model and Newton-Raphson method are compared for evaluation. U-net model shows good results as compared to other models.

U-Turn의 적정신호시간 모형구축에 관한 연구

오윤표,안영종,이영빈 東亞大學校 建設技術硏究所 2005 硏究論文集 Vol.28 No.2

In metropolitan, main streets manages 60-80% of the whole traffic in Korea even though its limited area and short extension. Main streets in urban has suffered congestion and a falling-off in capability of transportation due to its frequent discontinuity and disconnection. Especially Left-turn traffic mainly generates a shortage of fluidity in intersection although most intersection adopts Left-turn because of the peculiarity of traffic flows. To breakthrough this deterioration, U-turn system goes into effect in intersection of most main streets by reducing Left-turn phase or banning Left-turn at specific intersections to increase the fluidity of main direction. However, U-turn system lacks continuity and reveals security deficits because its legal basis and safety standard are not definitive. Therefore, this study, firstly, investigates the special characteristics of U-turn system, analyzes its effects based on the case of Busan city making the survey of drivers' awareness on U-turn. Then, secondly, This study aims to suggest more efficient and executive operating program for U-turn system by constructing proper Signal time model for U-turn.

한미 원자력 협력: 원자력 이용개발 협력 이슈와 쟁점

이상현 세종연구소 2019 국가전략 Vol.25 No.4

As environment-friendly, low-carbon energy, electricity production using nuclear power has temporarily decreased since the Fukushima accident in 2011, but it has been on the rise again. Growth of nuclear energy use, especially in Asia and emerging economies, is continuing. In terms of suppliers, Russia and China account for about two-thirds of new nuclear plants under construction. The Trump administration generally supports nuclear power generation, as it needs a nuclear renaissance to make America great again. The core of the energy policy pursued by the Trump administration is energy independence and the U.S. interests first. In contrast, the Moon Jae-in administration of South Korea is pushing energy conversion policy, also known as “nuclear phase-out” policy. The Moon Jae-in government confirmed the 3rd Basic Energy Plan, which aims to expand the use of renewable energy to 30-35 percent and reduce coal and nuclear power substantially by 2040. Although the Moon Jae-in government has set policy direction toward “nuclear phase-out” but is trying to expand nuclear export significantly. Seoul and Washington successfully revised the existing nuclear cooperation agreement in 2015 and laid a new foundation for nuclear energy cooperation. Future areas that require cooperation between South Korea and the U.S. include safety of nuclear power plants, decommissioning of stopped nuclear power plants, management of spent nuclear fuel, development of next-generation advanced nuclear power plants and cooperation in nuclear exports. South Korea pursues national energy conversion policy and nuclear exports simultaneously. The U.S. is concerned about the loss of its global nuclear leadership due to its shrinking capacity to supply nuclear power plants and declining competitiveness. Meanwhile, the global nuclear energy market is rapidly dominated by Russia and China. Therefore, Korea and the U.S. have no choice but to become natural partners. Seoul and Washington should map out a cooperative strategy through high-level consultations, and Seoul should reconsider its “nuclear phase-out” policy and redefine it as an energy advancement policy. 친환경 저탄소 에너지로서 원자력을 이용한 전력생산은 2011년 후쿠시마 사태 이후 일시적으로 줄었다가 다시 상승추세로 돌아섰다. 특히 아시아 지역 및 신흥국을 중심으로 하는 성장세가 이어지고 있으며, 공급자 측면에서 보면 러시아와 중국이 신규 원전 수주의 약 2/3 정도를 차지하고 있다. 트럼프 행정부는 전반적으로 원자력 발전을 지지하는데, 그것은 ‘미국을 다시 위대하게’ 만들기 위해 원자력 부흥을 필요로 하기 때문이다. 트럼프 행정부가 추구하는 에너지 정책의 핵심은 에너지 독립과 미국 이익 최우선이다. 이에 비해 한국 문재인 정부는 에너지 전환정책, 일명 ‘탈원전’ 정책을 추진하고 있다. 문재인 정부는 2040년까지 재생에너지 발전 비중을 30~35%로 확대하고 석탄·원전 비중은 크게 감축하는 내용을 담은 제3차 에너지기본계획을 확정했다. 문재인 정부는 탈원전으로 정책방향을 정했지만 원전 수출은 더욱 확대하려고 하는 입장이다. 한미 양국은 2015년 기존의 원자력협력협정을 성공적으로 개정하고 원자력 협력을 위한 새로운 기반을 마련한 바 있다. 향후 한미 간에 협력이 필요한 분야는 원전 안전, 폐로 해체, 사용후핵연료 관리, 차세대 첨단 원전개발, 원전수출 협력 등을 들 수 있다. 한국은 국가 에너지전환정책과 원자력 수출을 양립하려고 한다. 미국은 원전 공급 능력 및 경쟁력 저하로 전반적인 원자력 리더십 상실을 우려하고 있다. 그런 가운데 세계 원자력 시장은 러시아와 중국이 빠르게 장악해나가는 상황이다. 때문에 한국과 미국은 자연스런 파트너가 될 수밖에 없는 상황이다. 한미 양국은 고위급 협의를 통해 협력전략을 잘 짜야 하며, 한국은 ‘탈원전’ 입장을 재검토하여 이를 에너지 선진화 정책으로 재규정해야 한다.

G1 Phase Arrest of the Cell Cycle by a Ginseng Metabolite, Compound K, in U937 Human Monocytic Leukamia Cells

Kyoung Ah Kang,Yeong Wan Kim,Seung Uk Kim,Sungwook Chae,Young Sang Koh,김희선,추민경,김동현,현진원 대한약학회 2005 Archives of Pharmacal Research Vol.28 No.6

We recently reported that the ginseng saponin metabolite, compound K (20-O-β-D-glucopyranosyl- 20(S)-protopanaxadiol, IH901), inhibits the growth of U937 cells through caspase-dependent apoptosis pathway. In this study, we further characterized the effects of compound K on U937 cells and found that, in addition to apoptosis, compound K induced the arrest of the G1 phase. The compound K treated U937 cells showed increased p21 expression; an inhibitory protein of cyclin-cdk complex. The up-regulation of p21 was followed by the inactivation of cyclin D and the cdk4 protein, which act at the early G1 phase, and cyclin E, which acts at the late G1 phase. Furthermore, compound K induced the activation of JNK and the transcription factor AP-1, which is a downstream target of JNK. These findings suggest that the up-regulation of p21 and activation of JNK in the compound K treated cells contribute to the arrest of the G1 phase.

Investigation on reverse flow characteristics in U-tubes under two-phase natural circulation

Chu, Xi,Li, Mingrui,Chen, Wenzhen,Hao, Jianli Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.5

The vertically inverted U-tube steam generator (UTSG) is widely used in the pressurized water reactor (PWR). The reverse flow behavior generally exists in some U-tubes of a steam generator (SG) under both single- and two-phase natural circulations (NCs). The behavior increases the flow resistance in the primary loop and reduces the heat transfer in the SG. As a consequence, the NC ability as well as the inherent safety of nuclear reactors is faced with severe challenges. The theoretical models for calculating single- and two-phase flow pressure drops in U-tubes are developed and validated in this paper. The two-phase reverse flow characteristics in two types of SGs are investigated base on the theoretical models, and the effects of the U-tube height, bending radius, inlet steam quality and primary side pressure on the behavior are analyzed. The conclusions may provide some promising references for SG optimization to reduce the disadvantageous behavior. It is also of significance to improve the NC ability and ensure the PWR safety during some accidents.