Evaluation of a Dual-Cooled Annular Fuel Heat Split and Temperature Distribution

YANG, Yong Sik,SHIN, Chang Hwan,CHUN, Tae Hyun,SONG, Kun Woo Atomic Energy Society of Japan 2009 Journal of nuclear science and technology Vol.46 No.8

<P>The heat flux and fuel temperature of an annular fuel rod was analyzed using a newly developed program, DUO_THERM. The dual-cooled annular fuel rod has both inner and outer coolant channels. The heat fluxes to inner and outer claddings can change during irradiation because of the variation in the gap conductances of the inner and outer sides. The heat flux is a very important design factor affecting fuel integrity and safety. However, in an annular fuel design, the prediction of heat flux is very complicated because it is closely connected with size changes of two gaps, which are different from each other during irradiation. A burnup increase and power change can cause pellet and cladding radial deformation and eventually change the gap width. Because an annular fuel has two gaps at both sides and their heat resistances are very large, an imbalance of the gap width can lead to heat flux asymmetry. Therefore, a pellet and cladding dimensional change including densification, swelling, creep, and thermal expansion must be considered in the calculation of heat flux and temperature. By using the DUO_THERM program, the changes in heat flux and temperature during an operation were evaluated with respect to a reference design of an annular fuel. The results of the evaluation showed that the heat flux of an annular fuel was greatly affected by the inner and outer gap conductance changes. The heat flux of the inner cladding was maximum at zero burnup, but that of the outer cladding was maximum at the burnup of the outer gap closing. In addition, the maximum fuel temperature location was changed by gap conductance asymmetry.</P>

건축 프로젝트 적정 설계변경 관리를 위한 사례조사

김성욱(Kim Sung-Wook),남혜원(Nam Hye-Won),이종식(Lee Jong-Sik),신창현(Shin Chang-Hyun),전재열(Chun Jae-Youl) 대한건축학회 2009 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.29 No.1(구조계)

Recent design changes in the existing research on the factors and issues of design changes and analysis, responsible for analyzing the relationship, procedural issues, and issues of research that can be active. However, changes in the design of problems are essentially designed to complement the book is for the procedure. Methodology for dealing with design changes in the characteristics of the country and to reflect more realistically, and various design changes and looked at trends in related research. the design Change of this study to examine the domestic status and problems, identify the status of the country about the design changes, and in suggesting the direction to the development of the design changes.

Age-Associated Changes in the Vascular Renin-Angiotensin System in Mice

Yoon, Hye Eun,Kim, Eun Nim,Kim, Min Young,Lim, Ji Hee,Jang, In-Ae,Ban, Tae Hyun,Shin, Seok Joon,Park, Cheol Whee,Chang, Yoon Sik,Choi, Bum Soon Hindawi Publishing Corporation 2016 Oxidative medicine and cellular longevity Vol.2016 No.-

<P><I>Background</I>. This study evaluated whether the change in the renin-angiotensin system (RAS) is associated with arterial aging in mice.<I> Methods</I>. Histologic changes and expressions of transforming growth factor-<I>β</I> (TGF-<I>β</I>), collagen IV,<I> fibronectin</I>, angiotensin II (Ang II), angiotensin-converting enzyme (ACE), angiotensin-converting enzyme 2 (ACE2), angiotensin II type 1 receptor (AT1R), angiotensin II type 2 receptor (AT2R), prorenin receptor (PRR), Mas receptor (MasR), endothelial nitric oxide synthase (eNOS), NADPH oxidase 2 and oxidase 4 (Nox2 and Nox4), 8-hydroxy-2′-deoxyguanosine (8-OHdG),<I> 3-nitrotyrosine</I>, and superoxide dismutase 1 and dismutase 2 (SOD1 and SOD2) were measured in the thoracic aortas from 2-month-old, 12-month-old, and 24-month-old C57/BL6 mice.<I> Results</I>. Twenty-four-month-old mice showed significantly increased aortic media thickness and expressions of TGF-<I>β</I>, collagen IV, and fibronectin, compared to 2-month-old and 12-month-old mice. The expressions of PRR, ACE, and Ang II, and AT1R-positive area significantly increased, whereas expressions of ACE2 and MasR and AT2R-positive area decreased with age. The expressions of phosphorylated serine<SUP>1177</SUP>-eNOS, SOD1, and SOD2 decreased, and the 8-OHdG-positive area and the 3-nitrotyrosine-positive area increased with age. The expression of Nox2 significantly increased with age, but that of Nox4 did not change.<I> Conclusions</I>. The enhanced PRR-ACE-Ang II-AT1R axis and reduced ACE2-MasR axis were associated with arterial aging in mice. </P>

국내 중소하천의 유사량 산정 공식 적용에 관한 연구

강창훈 ( Chang-hoon Kang ),장석환 ( Suk-hwan Jang ),신철식 ( Cheol-sik Shin ),이현기 ( Hyeon-ki Lee ),김월봉 ( Wol-bong Kim ) 한국환경기술학회 2013 한국환경기술학회지 Vol.14 No.6

유사란 하천수에 의하여 운반되는 토사를 말하며 유수에 의해 침식, 퇴적이 반복되는 결과를 낳는다. 최근 기후변화와 함께 대규모 홍수가 빈번해 짐에 따라 하천의 유사량이 커지고 4대강 사업처럼 대규모 하천사업으로 인한 하상변동이 심해지고 있다. 하천에서 총유사량 추정은 하상변동의 원인이 되기도 하고 수자원 개발 및 관리를 위한 하천계획에 필요한 기본적 요소이다. 하지만 국내에서는 대규모 하천에서의 유사량은 측정을 실시하고 있지만 중소하천의 경우 유사량을 실측하여 산정할 수 있는 시간적 경제적 부담 때문에 측정할 수 있는 한계가 있다. 본 연구에서는 경기북부에 위치한 차탄천, 포천천, 경기남부에 위치한 남양천의 각 유량에 따른 부유사를 채취하여 시료분석을 통한 결과와 이론식을 적용하여 비교 분석 하였다. 채취한 시료는 입도분석을 실시하였으며 현장 측정 자료와 실내실험 결과를 토대로 수정 아인슈타인공식을 적용한 BORAMEP 프로그램을 사용하여 총유사량을 산정하였다. 분석 결과, 3m³/sec 이하 유량에서는 Yang 공식이 실측자료와 일치성을 나타냈고 3m³/sec 이상에서는 Shen and Hung 공식이 잘 나타났다. 각 이론을 적용하여 총유사량을 추정하고, 실측치를 이용하여 비교·검토함으로써 국내 중소하천에 적합한 산정 방법과 경기북부 지역 중소하천의 유량-총유사량 관계식을 제시하였다. Sediment transport means that the materials of bed and suspended load in the river are transported by flow tractive force, which causes scour and deposition. As the climate changes and dramatic flood occurs frequently, the sediment transport has increased and river bed changed. Sediment transport estimation is essential for the water resources management as well as river bed morphology. However, it is difficult to measure the total sediment in the middle and small river due to time and economic constrain. In this study, field data which were observed in 3 different river in Kyunggi-do were analyzed for comparing with empirical equations. Particle distribution analysis were carried out for the collected the suspended loads. The simulation model BORAMEP(Bureau of Reclamation Automated Modified Einstein Procedure) were used for the total sediment estimation along the field data analysis. As a result, Yang`s equation corresponds to field data under 3m³/sec and the equation of Shen and Hung corresponds to results over 3m³/sec. The results showed the way how sediment were estimated and discharge-total sediment relationship was determined by regression analysis in small and middle river of Kyunggi province region.

Analysis of Research Trends in Nitrous Oxide Emissions from Upland in Korea

Sun-Il Lee,Chang-Kyu Lee,Gun-Yeob Kim,Hyo-Suk Gwon,Jong-Sik Lee,Eun-Jung Choi,Joung-Du Shin 한국토양비료학회 2019 한국토양비료학회지 Vol.52 No.4

Global climate change, especially global warming is considered as threat to our future and posterity. Increasing concentrations of greenhouse gas such as carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) are the main causes of global warming. The Korean government has set a goal to cut the carbon emissions by 37% based on business-as-usual levels by 2030. According to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), agricultural sector is an important source of greenhouse gas emissions. In this regard, it is common belief that reducing of such emission is of great significance to global climate change. In Korea, upland is one of the main sources of agricultural N₂O emission. In order to analyze domestic research trends related to N₂O emissions in the upland, 53 academic publications from 2009 to September 2019 were critically reviewed. The results were classified according to the research purposes. Reduction technologies of N₂O emission account for approximately 28.3%. N₂O characteristics and assessment for 24.5%, development of N₂O emission factors for 22.6%, and N₂O inventory assessment for 20.8% etc. Biochar, green manure, no tillage, and inhibitor were studied as a means of reducing N₂O release. The optimum technologies to reduce N₂O emission in Korea were discussed and proposed through the previous researches.

Effects of viscoelastic material on the corneal endothelial cells in trabeculectomy with adjunctive mitomycin-C

Dong Bin Shin,Seung Bok Lee,Chang Sik Kim 대한안과학회 2003 Korean Journal of Ophthalmology Vol.17 No.2

We evaluated the change of corneal endothelium after trabeculectomy with mitomycin-C soaking (0.2 mg/ml, 2.4 ± 1.2 minutes) and the effect of viscoelastic material in reducing this change. In randomly selected cases, 0.05 ml of sodium hyaluronate (Healon??) was injected into anterior chamber (Healon group, n = 20), and same amount of balanced salt solution was injected in the other eyes (Control, n = 18) at the beginning of surgery. There were no differences in clinical variables and specular microscopy result between 2 groups before surgery. After surgery, the change of endothelial cells were significantly reduced in Healon group (cell density; -2.5 ± 1.6%, variability of cell area; 5.8 ± 2.5%, and percentage of hexagonal cell; -2.2 ± 0.7%) compared to control group (-7.7 ± 6.0%, 8.9 ± 4.4%, and -4.8 ± 3.5% respectively, p < 0.01). In trabeculectomy with mitomycin-C, the damage to the corneal endothelium was reduced significantly by injecting the viscoelastic material without significant complication.

Single Oral Dose Toxicity Evaluation of Leejung-tang, a Korean Traditional Herbal Formula, in Crl:CD (SD) rats

Lim, Hye-Sun,Lee, Mee-Young,Seo, Chang-Seob,Shin, In-Sik,Ha, Hye-Kyung,Huh, Jung-Im,Shin, Hyeun-Kyoo The Society of Korean Medicine 2011 대한한의학회지 Vol.32 No.3

Objective: Leejung-tang (Rechu-to in Japanese) is a traditional Korean herbal formula used for treatment of gastrointestinal disorders such as vomiting, stomach pain, chronic gastritis and gastrointestinal ulceration. The present study was carried out to investigate the potential acute toxicity of Leejung-tang water extract (LJT) by a single oral dose in Crl:CD (SD) rats in compliance with current guidelines. Methods: In the preliminary study, there were no adverse effects such as death, clinical signs, and body weight changes at dose levels of 500, 1000, and 2000 mg/kg/day body weight. Based on the results, a dose of 2000 mg/kg was selected as the toxicological limited dose. LJT was administered once by gavage to male and female rats at dose levels of 0 and 2000 mg/kg bodyweight. During the study period, mortalities, clinical findings, and body weight changes were observed for 14 days following the administration. On day 14 after the treatment, the animals were sacrificed by carbon dioxide overdose and complete gross postmortem examinations were performed. Results: In present study, no treatment-related deaths were observed. There were no adverse effects on clinical signs and body weight changes. In addition, there were no observed gross findings in all groups except for a kidney cyst in the 2000 mg/kg/day female group. Conclusion: The results indicated that LJT did not induce toxic effects at a dose level up to 2000 mg/kg in rats and its median lethal dose ($LD_{50}$) was considered to be over 2000 mg/kg/day body weight for both genders.

Single Oral Dose Toxicity Evaluation of Leejung-tang, a Korean Traditional Herbal Formula, in Crl:CD (SD) rats

Hye-Sun Lim,Mee-Young Lee,Chang-Seob Seo,In-Sik Shin,Hye-Kyung Ha,Jung-Im Huh,Hyeun-Kyoo Shin 대한한의학회 2011 대한한의학회지 Vol.32 No.3

랫드에서 쌍화탕의 급성독성에 관한 연구

김수정 ( Su Jeong Kim ),이미영 ( Mee Young Lee ),신인식 ( In Sik Shin ),서창섭 ( Chang Seob Seo ),하혜경 ( Hye Kyung Ha ),허정임 ( Jung Im Huh ),신현규 ( Hyeun Kyoo Shin ) 대한본초학회 2011 大韓本草學會誌 Vol.26 No.2

Objectives: This study was conducted to evaluate the acute toxicity and safety of Ssanghwa-tang (Shuanhetang in Chinese, Sou-wa-to in Japanese) in Crl: CD Sprague-Dawley (SD) rat though the current regulatory guideline. Methods: In this study, 10 rats of each sex were randomly assigned to two groups of 5 rats each and were administrated singly by gavage at dose levels of 0 and 2000 mg/kg/day of ssanghwa-tang water extract (SHT). After single administration of SHT, mortalities, clinical signs, body weight changes, gross findings were observed for the 15-day period. Results: Acute toxicity tests revealed that a single oral administration of SHT at dose levels of 2000 mg/kg did not affect clinical signs, body weight, and gross findings, evaluating the safety of SHT. The SHT treatment did not result in any toxicologically significant changes in mortality, clinical signs, body weight changes. Conclusions: These results showed that the single oral administration of SHT did not cause any toxic effect at the dose levels of 2000 mg/kg/day in rats. In conclusion, the median lethal dose (LD50) of SHT was considered to be over 2000 mg/kg/day body for both sexes.

정반 평면도 평가를 위한 측정점의 합리적인 개수의 결정

신상철,현창헌,박흥식 江原大學校 産業技術硏究所 1998 産業技術硏究 Vol.18 No.-

The flatness is the most important nature for the surface table. For finding such a flatness, the surface is surveyed along a number of straight lines parallel to the edges of table, which form a grid. Next, the variations in height of the grid points are measured relative to a datum point. If the number of such points is increased. It is not necessarily to use many grid points for finding the original flatness ofa measured surface tabel. So it is necessary to find the rational quantity of such grid points. It is found that about 220 points per 1 m? of surface tabel for measurement is the rational quantity with less than about 15% error of the original flatness.