• 한국초전도ㆍ저온공학회논문지
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• 제24권3호
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• pp.19-23
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• 2022

We have been developing a magnetic separation device that can be used in low magnetic fields for paramagnetic materials. Magnetic separation of paramagnetic particles with a small particle size is desired for volume reduction of contaminated soil in Fukushima or separation of iron scale from water supply system in power plants. However, the implementation of the system has been difficult due to the needed magnetic fields is high for paramagnetic materials. This is because there was a problem in installing such a magnet in the site. Therefore, we have developed a magnetic separation system that combines a selection tube and magnetic separation that can separate small sized paramagnetic particles in a low magnetic field. The selection tube is a technique for classifying the suspended particles by utilizing the phenomenon that the suspended particles come to rest when the gravity acting on the particles and the drag force are balanced when the suspension is flowed upward. In the balanced condition, they can be captured with even small magnetic forces. In this study, we calculated the particle size of paramagnetic particles trapped in a selection tube in a high gradient magnetic field. As a result, the combination of the selection tube and HGMS (High Gradient Magnetic Separation-system) can separate small sized paramagnetic particles under low magnetic field with high efficiency, and this paper shows its potential application.

• 한국초전도ㆍ저온공학회논문지
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• 제25권3호
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• pp.13-17
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• 2023

Magnetic separation technology for small paramagnetic particles has been desired for the volume reduction of contaminated soil from the Fukushima nuclear power plant accident and for the separation of scale and crud from nuclear power plants. However, the magnetic separation for paramagnetic particles requires a superconducting high gradient magnetic separation system applied, hence expanding the bore diameter of the magnets is necessary for mass processing and the initial and running costs would be enormous. The use of high magnetic fields makes safe onsite operation difficult, and there is an industrial need to increase the magnetic separation efficiency for paramagnetic particles in as low a magnetic field as possible. Therefore, we have been developing a magnetic separation system combined with a selection tube, which can separate small paramagnetic particles in a low magnetic field. In the previous technique we developed, a certain range of particle size was classified, and the classified particles were captured by magnetic separation. In this new approach, the fluid control method has been improved in order to the selectively classify particles of various diameters by using a multi-stage selection tube. The soil classification using a multi-stage selection tube was studied by calculation and experiment, and good results were obtained. In this paper, we report the effectiveness of the multi-stage selection tube was examined.

• 한국컴퓨터정보학회논문지
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• 제26권12호
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• pp.273-281
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• 2021

본 연구는 유튜브 먹방 콘텐츠 속성이 호감도, 만족도, 브랜드 선택에 어떠한 영향을 미치는가를 분석하여, 유튜브 먹방 콘텐츠의 활용이 어떤 형태로 이루어져야 하는지 그 방법을 찾는데 목적이 있으며, 외식 프랜차이즈 본부에서 유튜브를 활용한 전략적 마케팅 방안을 제안하고자 한다. 본 연구에서는 유튜브 먹방 콘텐츠 중 치킨 먹방을 시청한 경험이 있는 218명을 대상으로 설문을 실시하였다. 선행연구를 통해 유튜브 콘텐츠 속성을 정보성, 오락성, 신뢰성, 매력성으로 구분하였다. 연구가설의 검증을 위하여 단일 회귀분석, 다중회귀 분석을 실시하여 변수들 간의 관계를 확인하였다. 핵심 연구결과를 정리해보면 첫째, 유튜브 먹방 콘텐츠 속성이 호감도에 긍정적인 관계가 있는 것으로 나타났다. 둘째, 유튜브 먹방 콘텐츠 속성이 만족도에 긍정적인 관계가 있는 것으로 나타났다. 셋째, 호감도는 만족도에 영향을 미치는 것으로 나타났다. 넷째, 호감도는 브랜드 선택에 영향을 미치는 것으로 나타났다. 다섯째, 만족도는 브랜드 선택에 영향을 미치지 않는 것으로 나타났다. 이러한 연구결과로 볼 때 외식 프랜차이즈 본사의 유튜브 마케팅 활성화를 위하여 유튜브 먹방 콘텐츠를 통해 매력있는 정확한 정보 제공을 통해 이용자들의 호감도를 높이고, 지속적인 호감도 증진을 통해 브랜드 선택을 할 수 있도록 전략적인 접근이 필요할 것이다.

• 설비공학논문집
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• 제7권4호
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• pp.681-693
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• 1995

A new set of capillary tube selection charts for R-22 is proposed. The set of charts takes into account of the roughness effect on the mass flow rate. For this purpose, a set of numerical model is developed and a series of experiments is conducted to verify the numerical model. A numerical model is used to calculated the mass flow rate for several sets of tube diameter, length, inlet pressures and degree of subcooling. The outlet of the tube is controlled to be at critical condition. The experimental flow rate is compared with calculated values. The calculated values are consistently less than the experimental ones except for the flow rate range below 40kg/hr. The deviation is within 10---. Based on the nunmerical model and results of experiments, the set of capillary tube selection charts for R-22 is constructed. The set of charts consists of standard capillary tube chart(L=2030mm, d=1.63mm, ${\varepsilon}=2.5{\mu}m$), non -standard flow factor(${\phi}_1$) chart, and non-standard roughness factor(${\phi}_2$) chart. The mass flow rate, flow factor, and the roughness factor are defined respectively as; $\dot{m}={\phi}_1{\phi}_2\dot{m}_{standard}\\{\phi}_1=\frac{\dot{m}(L,\;d,\;\varepsilon_{standard})}{\dot{m}_{standard}(L_{standard},\;d_{standard},\;{\varepsilon}_{standard})}\\{\phi}_2=\frac{\dot{m}(L_{standard},\;d_{standard},\;{\varepsilon})}{\dot{m}_{standard}(L_{standard},\;d_{standard},\;{\varepsilon}_{standard})}$.

• 설비공학논문집
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• 제10권1호
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• pp.56-65
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• 1998

In this paper, experimental investigation of capillary tube performance for R-407C is performed. The experimental setup is made of real vapor-compression refrigerating system. In this study, mass flow rate is measured for capillary tubes of various diameter and length as inlet pressure and degree of subcooling are changed. These data are compared with the results of a numerical model. The mass flow rates of the numerical model are less than by 14% compared with the measured mass flow rates. It is found that mass flow rate and length for R-407c are less than those of R-22 under the same condition. Also based on this experimental study and the numerical model, a set of capillary tube selection charts for R-407C is constructed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.751-755
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• 2007

The purpose of this study is to find the optimization processing on expanded tube using Taguchi method which was generally used to analyze the effects of various control factors. Mini-Tab is a good for program that is making a selection using Taguchi method. The results of experimental test and analysis are as follows. Optimization processing on a expanded tube is dependent on lubrication condition. The slight eccentricity of expanded tube was obtained a good results on the expanded tube. When expending processing on the expanded tube was performed, the test specimens were almost unaffected by changing pressure loading. The tendencies of test results were related to lubrication condition and eccentricity in expending processing. As a result, a proper lubrication condition and eccentricity in the step of design will improve the optimization processing of expanded tube.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.209-211
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• 2022

전세계적으로 수많은 사람들이 이용하는 동영상 플랫폼 YouTube는 인기 급상승 동영상 서비스를 제공하고 있다. 본 연구는 공개 데이터셋 중 하나인 Kaggle 데이터셋을 이용하여 국가별 특징과 문화적 차이를 이해하고 공개 데이터셋의 유용성을 보이는 것을 목적으로 한다. 이를 위해 11개국, 15개 카테고리, 약 110만개의 인기 급상승 동영상 데이터를 분석 대상으로 한다. 데이터 분석을 위해 파이썬을 이용하여 카테고리 별 동영상의 개수와 인기 급상승 동영상 선정 기간, Unique 동영상 비율 등을 구하였으며, 이를 통해 국가별, 카테고리별 특징을 파악하고, 그 현상에 대한 배경을 추가 자료 조사를 통해 확인하였다. 향후 머신 러닝에 기반을 둔 인기 급상승 동영상 선정 가능성 및 선정 기간 예측을 통해 개별 동영상 진단 및 채널 운영 방안과 전략 수립에 도움을 주는 연구를 수행할 예정이다.

• 한국동물학회지
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• 제26권2호
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• pp.95-106
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• 1983

Drosophila melanogaster의 Oregon-R 계통과 lethal free 집단을 대상으로 connected test tube apparatus를 사용하여 보행행동에 관한 rapid와 slow 행동을 방향성도태의 방법으로 15세대 동안에 걸쳐 도태하였다. 한편 10세대째부터 natural selection을 행하여 유전적 효과를 분석하였다. 1. 보행행동의 rapid와 slow 성질은 초기세대에서부터 뚜렷한 도태효과를 나타내어 제 7세대 이후에 각각 selection plateau에 달하였다. 2. 방향성 도태를 10세대 동안 실시한 후 realized heritability를 계산한 결과 rapid 성질은 $9\\sim14%$, slow 성질은 $11\\sim16%$로서 rapid행동보다 slow 행동의 유전율이 다소 높게 나타났다. 3. Rapid 성질을 지배하는 유전자와 slow 성질을 지배하는 유전자의 우열관계를 밝히기 위한 hybridization 실험결과 slow 유전자가 rapid 유전자에 대하여 partial dominance의 효과가 있었다. 4. 10세대 동안에 걸쳐 방향성 도태를 실시한 후 natural selection을 5세대 동안 실시한 결과 rapid 성질은 단 5세대만에 neutral의 상태 (6.5)로 복원되었으나 slow 성질은 모집단의 보행지수와 비교하여 전혀 변화가 없었다. 실험결과로 미루어 rapid와 slow 형질은 polygenic system에 의하여 control 되는 양적 형질임을 알았다. 한편 rapid 유전자는 natural selection에 의한 homeostasis의 효과가 있으나 slow 행동은 소수의 major gene에 의하여 지배되는 것을 알았다.

• 한국임상수의학회지
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• 제35권5호
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• pp.184-189
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• 2018

Wild birds rescued for various reasons are injured and admitted to a wild animal rescue center. With the case of collision with cars, buildings and wires on a power pole, most wild birds are severely traumatized or get fractured, which need intensive veterinary treatment. In general, inhalation anesthesia to wild birds is the best choice for the medical and surgical procedure, and intubation is recommended for the stable anesthesia. Although the certain size of an endotracheal tube can be chosen depending on the size and morphology of the bird, there are a few standardized guidelines. Therefore, the optimal endotracheal size of the rescued 162 individual birds of 41 species for four years from March 2014 to December 2017 was investigated and sorted empirically, suggesting possibly the appropriate endotracheal sizes for diverse avian species. It may provide practical information data for wildlife veterinarians to select the size of an endotracheal tube according to the size of the domestic wild bird species, especially during surgery in the emergency cases.

• Nuclear Engineering and Technology
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• 제34권4호
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• pp.358-369
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• 2002

Abundant information about analyses of single steam generator tube rupture (SGTR) events is available because of its importance in terms of safety. However, there are few literatures available on analyses of multiple steam generator tube rupture (MSGTR) events. In addition, knowledge of transients and consequences following a MSGTR event are very limited as there has been no occurrence of MSGTR event in the commercial operation of nuclear reactors. In this study, a postulated MSGTR event in an APR1400 is analyzed using thermal-hydraulic system code MARSI.4. The present study aims to examine the effects of affected steam generator selection. The main steam safety valve (MSSV) lift time for four cases are compared in order to examine how long operator response time is allowed depending on which steam generate. (S/G) is affected. The comparison shows that the cases where two steam generators are simultaneously affected allow longer time for operator action compared with the cases where a single steam generator is affected. Furthermore, the tube ruptures in the steam generator where a pressurizer is connected leads to the shortest operator response time.