• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.622-624
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• 2004

To reduce the effect of fault on power systems, like GIS and transformers, power system authorities are using various technologies to monitor and diagnose there facilities. Developing On-Line monitoring systems by using IT technology is main issue of nowadays for power system authorities. Among various monitoring and diagnosis technologies, gas sensing technologies can be most useful candidate because large power systems are using gas and oils for there insulation and analyzing density of gases that are included in the gas and oils for insulation purpose tell us what kind of reaction were arisen. In this paper, we describe on the gas sensing technology that are used for power systems monitoring and diagnosis.

• 한국재료학회지
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• 제30권10호
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• pp.533-541
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• 2020

UO₂ kernels, a key component of fuel elements for high temperature gas cooled reactors, have usually been prepared by sol-gel methods. Sol-gel processes have a number of advantages, such as simple processes and facilities, and higher sphericity and density. In this study, to produce 900 ㎛-sized UO₂ particles using an external gelation process, contact length extension of the NH₃ gas of the broth droplets pass and the improvement of the gelation device capable of spraying 14 M-NH₄OH solution are used to form 3,000 ㎛-sized liquid droplets. To produce high-sphericity and high-density UO₂ particles, HMTA, which promotes the gelation reaction in the uranium broth solution, is added to diffuse ammonium ions from the outside of the gelation solution during the aging process and generate ammonium ions from the inside of the ADU gel particles. Sufficient gelation inside of ADU gel particles is achieved, and the density of the UO₂ spheres that undergo the subsequent treatment is 10.78 g/㎤; the sphericity is analyzed and found to be 0.948, indicating good experimental results.

• 대한기계학회논문집B
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• 제30권9호
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• pp.850-857
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• 2006

Hydrogen production using current fueling facilities is essential for near-term applications of fuel cells. A preliminary process for developing a natural gas autothermal reforming (ATR) reactor for fuel cells is presented in this paper. A experimental reactor for methane ATR was constructed and used for characterization of Jin reactor. Temperature profiles of the reactor were observed, and reformed gas compositions were analyzed to evaluate efficiency, conversion and reaction heat with varying amounts of $O_2/CH_4$ at selected furnace temperature and $H_2O/CH_4$. The amount of $O_2/CH_4$ showed strong offsets on reactor temperature, efficiency and conversion indicating that $O_2/CH_4$ is a crucial operation condition. Operation conditions which result in thermal neutrality of ATR reactor system were determined for two cases of an ATR system based on the estimation of enthalpy difference between reactants of assumed inlet temperatures and the products from experimental results. The determined conditions for thermally neutral operations could be used for guidelines to design reformers and for determining the operation parameters of a self sustaining ATR reactor.

• 한국물환경학회지
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• 제30권5호
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• pp.559-567
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• 2014

Since the ocean dumping of organic wastes is prohibited under the London Convention, the need for land treatment of food waste leachate (FWL) has significantly been growing in recent years. This study was conducted to use thermal solubilization to turn FWL into a form that can easily be degraded during the anaerobic digestion process, thereby reducing the percentage of solids and increasing the production of methane. To derive the optimal operating conditions of thermal solubilization, a laboratory-scale reactor was built and operated. The optimal reaction temperature and time turned out to be $190^{\circ}C$ and 90 min, respectively. The BMP test showed a methane production of 465 mL $CH_4/g$ $COD_{Cr}$ and a biodegradation rate of 90.1%. The production of methane rose by about 15%, compared with no the application of thermal solubilization. To reduce the solid content of FWL and improve the methane production, therefore, it may be helpful to apply thermal solubilization to pre-treatment facilities for anaerobic digestion.

• 대한지역사회영양학회지
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• 제7권4호
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• pp.559-570
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• 2002

This research was to investigate the operation of contracted food service management and menu preferences of middle school students in Seoul. Questionnaires were distributed between Dec. 1 and 20,2000 in 10 middle schools. Statistical data analyses were completed using the SAS package, including the mean, standard deviation and frequency analysis. The results can be summarized as follows: The average number of meals per middle school was 1,000 and only lunch was served in each school. In terms of facilities and equipment, low rates of the possession of cooking equipment and food carts were the major hindrance to work and production efficiency. The students' main demands were taste, sanitation, variety of food, the introduction of brand foods, the price of foods, and the speed of reaction to their dissatisfaction. Most of the schools provided rice for lunch, while the students preferred noodles, mandu and bread. beef-rib soup was preferred to broth. for side dishes, fish, roasted meat and fried foods were highly favored, along with processed foods, with low preferences for vegetables. The middle school students favored fruits. Lastly, they requested that the quality of school meals be improved through the development and supply of various desserts.

• 한국조리학회지
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• 제4권
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• pp.369-387
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• 1998

The atmosphere of foodservice facility is considered to be the total environment to which customers are exposed. Atmosphere is sometimes described as everything that makes an impression on people. On the other hand, mood is best described as the response of an individual to the various components that make up the atmosphere. Most people experience some type of reaction to the atmosphere that may be desirable or undesirable. If the individual response to the foofservice facility is favorable, the atmosphere has served to put that person into a good mood. In the highly competitive commercial restaurant field, the planning of the atmosphere for new facilities is going to be more important. The coming generation of potential customers is growing up in an environment that associates dining out with more than just good food. This study is characterized by the right atmosphere offerings. Thus, this study discusses the physical components affecting perception of atmosphere. Many of these components will be discussed in detail to show their relationship to the design of dining areas. This study identified the many physical components of atmosphere that can be manipulated and arrive at a combination that will give the desired sensations. With these backgrounds as a guide, this study presented alternatives which should not only provide atmosphere but should reach a satisfactory level of creating atmosphere from a practical standpoint. these is to maximise the perceptual effect, train the employees, and be reflected and be reflected the advertising and public relations.

• 가정과삶의질연구
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• 제19권6호
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• pp.113-128
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• 2001

middle and upper class families, and examine obstacles to their introduction in Korea. Since a few large-scale facilities for the elderly with dementia have been provided for only low-income families free of charge, the necessity of group homes for middle and upper class families willing to pay for such services has become an issue recently in order to lessen the burden on families, as well as to promote the well-being of the dementia victims themselves. The survey was conducted by questionnaires collected from 577 respondents from middle and upper class families. The results of the survey were as follows: The merits of the group homes were 1)decreasing loneliness of the elderly, 2)providing active and stimulating environments allowing for participation everyday life activities, and 3)lessening the emotional and physical burden on the caring families. Potential obstacles to its introduction in Korea were 1)the difficulty of finding sites to build the group home because of the negative perception of people with disabilities and a NIMBY(Not In My Back Yard) reaction to the construction of it and 2)the economic burden on the caring family. Surprisingly, the guilt factor associated with sending the parents into group homes was not considered as a big obstacle. Referring to results of this study, it is asserted that group homes for the elderly with dementia would be embraced throughout the country if Koreans could have the chance to understand what group homes are.

• 한국수자원학회논문집
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• 제36권1호
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• pp.75-85
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• 2003

시가지의 확장과 개발 등으로 인한 도시에서의 강우-유출현상은 자연하천유역에 비하여 더욱 복잡한 양상을 가지며, 실제 유역의 변화로 인하여 모형의 적용이 매우 어려운 편이다. 본 연구에서는 SW 모형과 전문가 시스템을 적용하여 도시화 유역에서의 유출 특성을 파악하였다. 연구 유역으로는 대전광역시에서 노은지역을 선정하였으며, 실제 유역 및 시설자료, 강우, 유출자료와 다양한 강우강도식을 사용하였다. 매개변수의 추정 과정을 위하여 전문가시스템을 사용하였으며, 본 결과들을 통하여 설계 강우의 시간 분포 및 도시화에 따른 도시 유역의 반응 경향을 해석할 수 있었다.

• 대한안전경영과학회지
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• 제19권4호
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• pp.149-155
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• 2017

This study is analyzed combustion phenomena based on the environmental energy facility incinerator. It is assumed that combustible components of waste are composed of carbon and hydrogen, and the combustion process of fuel is by setting as multi-component / multistage reaction. As the combustion chamber is burned, the high temperature environment is achieved, also the heat transfer accompanied by the turbulent flow and the generation of NOx, a pollutant, are interpreted to predict the thermal and fluid characteristics and pollution emissions of the grate incinerator. As the result of internal flow analysis, the slow flow around the ash chute and the mixing effect due to the complicated turbulence around the combustion chamber were predicted to show excellent performance. It is shown to the internal average temperature was about $1024^{\circ}C$, around the about $1000^{\circ}C$ homogeneous temperature distribution. Due to the sudden temperature decrease in the boiler, the flue gas temperature at the outlet was estimated to be about $220^{\circ}C$.

• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.961-968
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• 2022

Hydrogen embrittlement leads to the damages in bolts, nut, especially, high pressure valves, in the semiconductor facilities, hydrogen vehicles, hydrogen stations and so on. Monel material has higher strength than SUS material. Therefore, even though Monel material with special alloy is usually used to prevent the hydrogen embrittlement, it needs powerful drawing system to manufacture the rectangular or hexagonal bar using circular bar. The purpose of this study is to investigate the characteristics of plastic deformation of Monel material and 2 rollers of rolling unit in plastic limit through numerical analysis. As the results, it was predicted that, based on mean stress, as the rolling step was increased, the rolling force of rolling unit was decreased. In addition, the heat treatment for Monel material was needed because of residual stress due to plastic deformation. As for rollers, the roller was safe about 1.86 times compared with that of ultimate strength. In this study, as the roller 2 showed larger stress than roller 1, thus, roller 2 should be designed carefully to guarantee the safety. Further it was confirmed that the reaction force of roller could be helpful in bearing design.