• Nuclear Engineering and Technology
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• 제45권5호
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• pp.589-596
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• 2013

In a pressurized heavy water reactor, following loss of the primary coolant, severe core damage would begin with the depletion of the liquid moderator, exposing the top row of internally-voided fuel channels to steam cooling conditions on the inside and outside. The uncovered fuel channels would heat up, deform and disassemble into core debris. Large inventories of water passively reduce the rate of progression of the accident, prolonging the time for complete loss of engineered heat sinks. The efficacy of available backup and ultimate heat sinks, available in a CANDU 6 reactor, in mitigating the consequences of a prolonged station blackout scenario was analysed using the MAAP4-CANDU code. The analysis indicated that the steam generator secondary side water inventory is the most effective heat sink during the accident. Additional heat sinks such as the primary coolant, moderator, calandria vault water and end shield water are also able to remove decay heat; however, a gradually increasing mismatch between heat generation and heat removal occurs over the course of the postulated event. This mismatch is equivalent to an additional water inventory estimated to be 350,000 kg at the time of calandria vessel failure. In the Enhanced CANDU 6 reactor ~2,040,000 kg of water in the reserve water tank is available for prolonged emergencies requiring heat sinks.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.43-50
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• 1998

The current design equations for ultimate strength of tubular joints are based on a limited number of experimental results performed on simple joints with simple loading conditions and depend on value of the branch to the chord diameter- ratio $\beta$ too much. Therefore, the purpose of this study is to estimate the ultimate strength of CHS tilbular joints considering the effects of branch inclination angles $\theta$, chord length to diametel ratio $\alpha$ and chord end conditions by finite element analysis. The analyses are performed using finite element software ADINA that is capable of modeling elasto-plastic material behavior as well as geometric nonlinearities. The results show that the current use of sin $\theta$ in normalized design equations for inclined branches is reasonable, but somewhat conservative. When compared with the previous experimental database, the close numerical results are obtained from the parametric studies on the static strength of T-, Y-, DT- and X-joints. Also, a new design equation for ultimate stregth of CHS tubular joints is derived using a modified version of the ring model which can include the effects of $\alpha$ and chord end condtion.

• 안보군사학연구
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• 통권3호
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• pp.35-72
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• 2005

The purpose of this paper is to recommend the Ministry of Defense(MOD) for revolutionizing the current defense education system. As an instructor and an education planning officer of the ROK Army College, for last dozen months, the author has been embarrassed whenever tried to figure out what would be the role, functions, and educational goals of the college. In a nutshell, there has not been any general guidance for educating field grade officers. This unbelievable defect mainly comes from the absence of a responsible organization in the MOD. Even though it has the education branch under the department of personnel affairs, it doesn't have capabilities to design and implement the consistent and valuable education policy. Therefore, the development of defense education should begin with reinforcing the organization and functions of the MOD education branch. We need more experts on education( i.e. Ph.Ds of Education) and experienced specialties on defense education so that we could develop the overall guidance for military professional education. In addition, we need to enact the "defense or military education act" in a tentative name. This will ensure the legitimacy and continuity of defense education guidance initiated by the MOD. In a conclusion, it is senseless to think the blueprint for the Army College out until the preconditions mentioned above are matured. We must begin with rectifying the higher educational system.

• ETRI Journal
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• 제37권5호
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• pp.945-950
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• 2015

A novel microstrip low-pass filter is presented to achieve an ultra-wide stopband with 11 harmonic suppression and very sharp skirt characteristics. The filter is composed of a modified U-shaped resonator (which creates two fully adjustable transmission zeroes), a T-shaped resonator (which determines a cut-off frequency), and four radial stubs (which provide a wider stopband). The operating mechanism of the filter is investigated based on a proposed equivalent-circuit model, and the role of each section of the proposed filter in creating null points is theoretically discussed in detail. The presented filter with 3 dB cut-off frequency ($f_c=2.35GHz$) has been fabricated and measured. Results show that a relative stopband bandwidth of 164% (referred to as a 22 dB suppression) is obtained while achieving a high figure-of-merit of 15,221.

• 수산해양기술연구
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• 제29권2호
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• pp.132-151
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• 1993

The proposed method in this paper. termed the substructural reanalysis technique, utilizes the computational merits of the component mode synthesis technique and of reanalysis technique for the design sensitivities of the dynamic characteristics of substructurally combined structure. It is shown that the dynamic characteristics of the entire structure can be obtained by synthesizing the substructural eigensolution and the characteristics of the eigensolution for the design variables of the modifiable substructure. In this paper , the characteristics of the eigenvalue problems obtained by this proposed method are compared to exact eigensolution in terms of accuracy and computational efficiency. and the advantage of this proposed method as compared to the direct application of the whole structure and experimental results is demonstrated through examples of numerical calculation for the dynamic characteristics (natural frequencies and mode shapes) of a flexible vibration of thin cylinderical shell with branch shell under 2-end fixed positions, boundary condition. Thin cylinderical shell of overall length 1280mm, external diameter 360mm, thickness 3mm with branch shell is made of mild steel. The load condition for dynamic response in this paper is impulsive load of which magnitude is 10kgf, which have short duration of 0.1 sec. and time interval applied to calculate. $\Delta$T is 1.0$\times$10 super(-4) seconds.

• 한국지하수토양환경학회지:지하수토양환경
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• 제24권2호
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• pp.23-37
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• 2019

To evaluate the available groundwater supply to the agricultural water demand in the future with the climate change scenarios for 40 sub-regions in Jeju Island, groundwater recharge and the available groundwater supply were estimated using water balance analysis method. Groundwater recharge was calculated by subtracting the actual evapotranspiration and direct runoff from the total amount of water resources and available groundwater supply was set at 43.6% from the ratio of the sustainable groundwater capacity to the groundwater recharge. According to the RCP 4.5 scenario, the available groundwater supply to the agricultural water demand is estimated to be insufficient in 2020 and 2025, especially in the western and eastern regions of the island. However, such a water shortage problem is alleviated in 2030. When applying the RCP 8.5 scenario, available groundwater supply can't meet the water demand over the entire decade.

• 한국환경과학회지
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• 제22권6호
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• pp.695-703
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• 2013

In this study, the effects of four major river project and Kumho River, second biggest branch of Nakdong River, were investigated to provide basic data for proper management of Nakdong River's water quality. Daily sampling processes at three different points, Munsanri (the upper side of Kangjung-Koryung weir), Kangchang (the outlet of the Kumho River) and Samunjin (the lower side of Kangjung-Koryung weir and junction of Kumho River and Nakdong River), were conducted from May 1st 2011 to Sep. 4th 2011. Water samples were analyzed for nine factors, DO, BOD, COD, T-N, T-P, pH, turbidity, SS, and coliform. As demonstrated by the results, concentrations of BOD, T-N, T-P and coliform at Nakdong River were affected by water quality of Kumho River while SS and turbidity were affected by constructions for Kangjung-Koryung weir. Further studies, for example, affects of wastewater treatment facilities, should be followed.

• 한국환경복원기술학회지
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• 제12권6호
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• pp.143-152
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• 2009

This study has been carried out to estimate carbon contents in an average 37-years-old Pinus densiflora plantations and an average 42-years-old natural Quercus acutissima stands in Gongju, Chungnam Province. Average carbon concentration in stemwood, stembark, branch, foliage, and root were 54.59% in Pinus densiflora and 53.73% in Quercus acutissima stands. Aboveground carbon contents was estimated by the equation model logWt = A + BlogD where Wt is oven-dry weight in kg and D is DBH in cm. Total carbon contents was 79.28t/ha in Pinus densiflora stands and 71.52t/ha in Quercus acutissima stands. Net primary carbon production was estimated at 9.79tC/ha/yr in Pinus densiflora stands and 5.52tC/ha/yr in Quercus acutissima stands.

• 중환자간호학회지
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• 제16권2호
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• pp.54-66
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• 2023

Purpose : Developing infection control capabilities during the COVID-19 pandemic was critical. This study aimed to develop a simulation program to control patients with COVID-19 in nursing students and examine the effects on COVID-19 knowledge, COVID-19 nursing intention, self-efficacy learning, and clinical performance. Methods : The study used nonequivalent control group pretest-posttest design. Sixty nursing students were recruited from two different colleges using purposive sampling. For the intervention group(n=30), the pretest was administered before the simulation program, involving six sessions of online lectures and simulation practices. Immediately, the posttest was conducted following the program. Results : COVID-19 knowledge (t=9.87, p <.001), COVID-19 nursing intention (t=4.45, p <.001), learning self-efficacy (t=6.49, p <.001), and clinical performance (t=6.77, p <.001) increased significantly after the program, revealing the positive effect of the COVID-19 infection control simulation program in nursing students. Conclusion : The results of the study and the curriculum may be used as practical evidence for COVID-19 infection control in nursing schools and medical institutions.

• Journal of Yeungnam Medical Science
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• 제4권2호
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• pp.23-27
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• 1987

저자들은 1986년 5월부터 1987년 4월까지 건강 진단 목적으로 검사한 대구시내 국민학생 및 중학생의 심전도를 분석하여 다음과 같은 결론을 얻었다. 대상학생은 13,801명으로 남자 7,526명, 여자 6,275명이였다. 심전선도에서 이상소견을 보인 수는 145명(1.05%)으로 남자 98명, 여자 47명이였다. 심방 및 심실비대는 우심방비대 2명, 좌심방비대 5명, 우심실비대 35명(0.25%) 및 좌심실비대 16명(0.12%)이였다. 이소심박중 심방성 조기수축 12명(0.09%), 심실성 조기수축 8명(0.06%) 및 방실접합부율동 5명(0.04%)이였다. 정도장애 부정맥중 1도방실전도장애 21명(0.15%), 1형 2도방실전도장애 1명, 방실해리 1명, 우각전도차단 36명(0.26%), 좌각전도차단 1명 및 WPW증후군 2명이였다. 비특이적 ST, T변화가 3명이였고, 동성빈맥이 1명이였다.