• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.292-292
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• 2010

양성자기반공학기술개발단에서는 100MeV와 20MeV의 가속기를 개발하고 있으며 빔 이용을 위하여 각 에너지에 5개의 빔라인을 구축 할 계획이다. 빔라인에는 각 마그넷과 빔 계측, 진공 등의 부품이 포함되어 있다. 본 연구에서는 빔라인의 기초 구성품인 진공 부품의 설계를 위한 압력의 계산을 수행하였다. 각 빔라인 재질에 따른 gas load는 표면의 아웃게싱이 주요하게 고려되었으며 고진공용 Cu gasket의 진공 leak는 거의 없다고 가정하였다. 재질은 스테인레스스틸과 알루미늄의 두 가지 경우를 사용하였으며 주 배기 펌프는 이온펌프로 펌핑 스피드 125L/s의 diode 타입이다. 빔튜브의 사이즈는 CF6"의 규격 플랜지를 기본으로 빔 사이즈가 고려된 여러 플랜지의 조합으로 내부 부피를 구할 수 있었다. 빔라인 뿐만 아니라 타겟룸에 위치되어지는 튜브를 합한 경우와 펌프의 개수를 다르게 하였을 때에도 길이에 따른 압력의 프로파일을 계산하였다. 빔을 분배해 주는 AC 마그넷 이전에 이온펌프 한 개를 위치하였을 때 스테인레스스틸 빔 튜브의 경우에 최대값은 1.3E-6 torr, 최소값은 1.7E-6 torr 으로 계산 되었다. 이 결과는 가속기의 아래쪽 3개의 빔라인을 동시에 배기하고 빔 조사가 가능하도록 운영되는 조건이며 운영 마진 2배를 고려한다고 하여도 최소 진공도는 3.4E-6 torr 이다. 이온펌프는 일반적으로 9.0E-6 torr 이하에서 사용이 가능하므로 이온펌프 1개의 진공도로도 운영에 무리가 없으며 이온펌프의 수가 증가됨에 따라서 최대 도달 압력이 낮아짐을 알 수 있다.

• Journal of Korea Water Resources Association
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• v.46 no.6
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• pp.629-642
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• 2013

In this study, the efficiency of the by-pass fishway installed at Kangjung-Goryong Weir in Nakdong River was assessed by using River2D which is a two-dimensional physical habitat simulation model. The model was calibrated and validated through the measured water elevation. The assessment was performed according to flow condition such as flood, normal, and low flow. Especially the low flow condition was focused on because the target fish, Zacco Platypus, have moved frequently up and downstream at the spawning season from April to June. From simulation results, it can be deduced that the influx efficiency and the passage efficiency of the fishway in the low flow is higher than that in the flood and normal flow due to occurrence of proper velocity at fishway entrance.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.366-366
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• 2023

우리나라 농촌 지역의 농업용저수지는 유역면적이 작고 홍수 도달시간이 짧아 홍수 대응에 어려움이 있으며, 대부분의 농업용저수지는 용수공급 목적으로 건설되어 홍수 대응능력이 부족한 실정이다. 한국농어촌공사는 수자원, 재난재해 등 농촌용수 관련된 다양한 정보의 통합관리를 위한RAWRIS(Rural Agricultural Water Resource Information System)을 운영하고 있으나, 소하천 및 농촌 지역의 홍수 피해 저감에 대한 관리와 노력은 도시 지역의 대하천 유역과 비교하여 여전히 부족한 실정이다. 이에 본 연구에서는 농촌지역의 과학적 재해관리를 위해 RAWRIS의 홍수량 산정기술을 개선하고, 저수지 홍수예경보에 필요한 기상청 초단기 강우예측자료의 활용성을 검토하고자 하였다. 이를 위해 농어촌공사에서 관리하는 농업용저수지 중 홍수배제시설인 레디얼게이트가 설치된 농업용저수지 30개소를 대상으로 해당 저수지의 수위계측 정보, 수문 방류 정보 등 저수지 홍수관리 현황을 조사하였다. 다음으로 농어촌공사가 운영 중인 RAWRIS의 홍수량 산정과정을 검토하여, 기존 RAWRIS에 CN값이 미설정된 저수지 유역의 CN값을 설정하였으며, 유역의 강우량 및 유효우량 산정 알고리즘 개선하고 저수지 유역별 강우-유출모형의 대표 매개변수를 제시하였다. 마지막으로 기상청에서 제공하고 있는 초단기 강우예측자료의 활용성 평가를 위해 기상청 강우예측자료와 저수지 유역의 면적평균강우를 비교하였으며, 예측 및 관측강우에 의한 홍수유입량을 산정하여 그 결과를 비교하였다. RAWRIS 홍수량 산정기술의 개선 효과를 검토한 결과, 예당저수지의 경우에는 첨두유량백분율 오차가 최대 50 % 이상, 결정계수(R2)가 최대 0.6 이상 개선된 것으로 나타났다. 다음으로 초단기 강우예측자료의 활용성을 평가하기 위해 RAWRIS에 제공되는 기상청 강우예측자료와 관측강우자료을 비교한 결과, 초단기 예측강우자료는 정량적, 정성적 신뢰도의 문제가 있어, 농업용저수지 홍수예측시스템에 그대로 적용하는데에는 무리가 있는 것으로 나타났다.

• Korean Journal of Environment and Ecology
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• v.23 no.5
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• pp.418-430
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• 2009

The main purpose of this study is to investigate the relationship between the topography of land and vegetation and the preferred habitat of wintering cranes. Investigations were conducted twelve times in Cheorwon basin, South Korea, during two wintering seasons (12/2005 - 2/2006; 1/2007 - 2/2007). The density of rice grain in the middle of rice paddies was higher than that of the areas along the edge of rice paddies. However it was observed that red-naped cranes preferred to feed along the edges of rice paddies rather than to feed in the middle of the paddies. White-naped cranes, on the other hand, Preferred to feed in the middle of paddies. To be more specific, red-crowned cranes preferred feeding sites such as levees of the paddies or the areas where the level of the rice beds was comparatively more elevated. But the preference of the white-naped cranes turned out to be just the opposite. Another finding was that both red-naped cranes and white-naped cranes preferred concealed areas for their feeding site, and the frequency rate of their feeding in concealed areas has little to do with weather factors. This finding contradicts a widely accepted view that cranes prefer open spaces for their feeding site. Besides, red-crowned cranes, compared with white-naped cranes, preferred to feed in more concealed areas. The frequency rate of feeding in both concealed areas and non-concealed areas had little to do with the size of feeding flocks. There was no difference between a flock of fewer than five cranes and a flock of more than five cranes in terms of frequency rate of their feeding. In conclusion, the result of these investigations indicate that red-naped cranes comparatively prefer concealed areas for their feeding site, and white-naped cranes are less prone to them, and there is no direct connection between their preference of feeding site or frequency and the size of their flock. This is presumed to be the characteristics unique to their individual species.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3587-3593
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• 2009

Nowadays, the PV systems have been focused on the interconnection between the power source and the grid. The PV inverter, either single-phase or three-phase, can be considered as the core of the whole system because of an important role in the grid-interconnecting operation. An important issue in the inverter control is the load current regulation. In the literature, the Proportional+Integral (PI) controller, normally used in the current-controlled Voltage Source Inverter (VSI), cannot be a satisfactory controller for an ac system because of the steady-sate error and the poor disturbance rejection, especially in high-frequency range. By comparison with the PI controller, the Proportional+Resonant (PR) controller can introduce an infinite gain at the fundamental ac frequency; hence can achieve the zero steady-state error without requiring the complex transformation and the dq-coupling technique. In this paper, a PR controller is designed and adopted for replacing the PI controller. Based on the theoretical analyses, the PR controller based control strategy is implemented in a 32-bit fixed-point TMS320F2812 DSP and evaluated in a 3kW experimental prototype Photovoltaic (PV) power conditioning system (PCS). Simulation and experimental results are shown to verify the performance of implemented control scheme in PV PCS.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.479-486
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• 2022

Midlife is a critical time when people look back on their life and evaluate it from current state. In middle age, there is a satisfaction with achievement and a sense of crisis between reality and expectation. Research on pastoral counseling in the middle age to minimize problems and conflicts that occur in the transition period of crisis or opportunity is meaningful. Based on biblical principles, pastoral counseling should be able to help the client's needs and development tasks to be reproduced into a meaningful life on the basic premise of a realistic meeting with God. Therefore, through a literature review, the developmental views of Jung, Ericsson, Levinson, and the pioneers of middle-aged research, were examined. From this realistic point of view, the integration of pastoral counseling and reality therapy is considered to be very useful by allowing the harmony of internal dialogue and behavior to start together through the feasible realistic behavior and responsibility of one's choice. Insights on oneself and specific counseling methods of realistic therapy will present a new type of counseling through integration with pastoral counseling. Therefore after examining the theoretical background and characteristics of reality therapy, we intend to help overcome the middle-aged crisis through the meeting pastoral counseling and reality therapy.

• Journal of Radiation Protection and Research
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• v.21 no.3
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• pp.183-200
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• 1996

Many information channels have dealt with the radiological consequences of the Chernobyl accident in different voices ever since the time of the accident. Large differences in the data about the amount of released radioactivity, losses of life, environmental effects and economic damage confuse the information receiving group. The intention of this paper is to provide an insight to the consequences of the accident through review of the reports and articles on the given issue and the scientific background. The formal reports reviewed include those from IAEA, EC, OECD/NEA, the governments of the two most-affected countries; Belarus and Ukraine. Much consideration was paid to make the text as plain as possible.

• Journal of the Korean Magnetics Society
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• v.4 no.2
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• pp.184-187
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• 1994

Nuclear magnetic resonance of $^{133}Cs$ in a $CsMnCl_{3}$ single crystal grown by the Czochralski method has been investigated by employing a Bruker FT NMR spectrometer. The $^{133}Cs$ resonance of two different groups were recorded. Various transitions belonging to two cesium spectra of a different intensity ratio are analyzed. The quadrupole coupling constant of Cs(I) is $0.15{\pm}0.01$ MHz, and that of Cs(II) is $0.21{\pm}0.01$ MHz. The anisotropy parameter is zero for both. The principal axes of the EFG tensors for these two sites are found to be the same. The Z axis, conventionally the largest component of the EFG tensor, is parallel to the crystallographic c-axis.

• Geotechnical Engineering
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• v.14 no.4
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• pp.163-176
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• 1998

To apply piezocone test to soil classification, several classification charts based on correlations between its results and basic characteristics of soils have been developed. However, it is necessary to investigate their applicability to Korean soil, since they were the results obtained from the limited number of foreign sites. In this study, 41 piezocone penetration bests for various sixtes spreading widely over Korean territory were carried out. Correlations between piezocone teat results and basic characteristics and the applicability of existing classification charts were investigated. Conclusively, new classification charts based, on Unified Soil Classification System were developed with a local confidence.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.363-365
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• 2006

소비자의 요구와 기술력의 발달로 PDP시장은 42인치와 60인치등 대형PDP가 주류를 이루고 있으며 대형화에 따라서 PDP전원의 소모전력 또한 $400W{\sim}600W$ 까지 증가 하고 있다. 기존 소용량 PDP전원으로 사용되던 Flyback의 경우 소모 전력이 증가함에 따라 대형PDP에 적용하기에는 소자 내압 및 시스템 효율 측면에서 다소 무리가 있다. 따라서 대형PDP의 전원을 위해서 새로운 2 Switch 3 Diode를 채용한 고효율 DCR (Diode Clamping Rectifier) Flyback Converter를 제안하였으며 이를 42인치 PDP에 적용하여 회로의 타당성 및 우수성을 검증하였다.