• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.752-754
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• 1999

When we are trying to retrofit turbine control system from analog system to digital one, a new communication network is required to be contstructed. In this paper, we are going to introduce one example of economic communication network, which is reliable in operation from control room and field instruments to office and computer room. It will be installed in a power plant in the case of retrofiting control system of medium size steam turbine.

• 대한지구과학교육학회지
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• 제7권1호
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• pp.75-90
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• 2014

The purpose of this study was to explore the characteristics of STEAM program developed and implemented by two docents and its educational impact for the use of natural history museum. Two docents developed this program with the help of science educators who ran five times of workshop during five months. The STEAM program implemented in the natural history museum demonstrated the following characteristics. The exhibitions in museum were reached by visitors only for learning science concepts (S) out of five components in STEAM. The other components, T (technology) and E (engineering), were delivered through lectures in the room, not exhibition hall. M (Mathematics)was achieved by guessing the animal's size, or calculating the walking or running speed with the clue of foot prints. The three phases of STEAM program (presentation of context, creatively design the investigation, and emotional touch) were explicitly implemented but partially successful. Two docents participating in this study responded that they formed new or extended the understandings about STEAM education, but they had the difficulties in implementing STEAM program for various type of visitors. All visitors who participated in this study displayed the favorable responses in educational impact by STEAM program in natural history museum. The heavier emphasis on E and T of STEAM program is recommended through community-based learning. In addition, educator professional program through which docents can bridge theory into practice is suggested for revitalization of STEAM education.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.379-380
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• 2002

Steam generators (S/G) of pressurized water reactors are large heat exchangers that use the heat from the primary reactor coolant to make steam in the secondary side for driving turbine generators. Reciprocating sliding wear experiments have been performed to examine the wear properties of Incoloy 800 and Inconel 690 steam generator tubes in high temperature water. In present study, the test rig was designed to examine the reciprocating and rolling wear properties in high temperature (room temperature - $300^{\circ}C$) water. The test was performed at constant applied load and sliding distance to investigate the effect of test temperature on wear properties of steam generator tube materials. To investigate the wear mechanism of material, the worn surfaces were observed using scanning electron microscopy. At $290^{\circ}C$, wear rate of Inconel 690 was higher than that of Incoloy 800. It was assumed to be resulted from the oxide layer property difference due to the a\loy composition difference. Between 25 and $150^{\circ}C$ the wear loss increased with increasing temperature. Beyond $150^{\circ}C$, the wear loss decreased with increasing temperature. The wear loss change with temperature were due to the formation of wear protective oxide layer. From the worn surface observation, texture patterns and wear particle layers were found. As test temperature increased, the proportion of particle layer increased.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.263.1-263
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• 2001

• 펄프종이기술
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• 제33권3호
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• pp.75-83
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• 2001

The potential of oxygen delignification is a powerful tool to reduce detrimental environmental effects. This study was performed to investigate the effect of steam explosion treatment of chemically treated oak wood on oxygen-alkali pulping. Pulp yield during steam explosion treatment by ${Na_2}{O_3}$-NaOH impregnation was higher than the other impregnation chemicals. Also, NaOH extraction at room temperature after steam explosion treatment improved the kappa number from 140~116 to 90~64. Oxygen-alkali pulping of chemical steam explosion treated woods affected to pulp yields. ${Na_2}{O_3}$-NaOH impregnation was very effective to higher carbohydrate yields at same delignification level. Its carbohydrate yield seemed to be highly related to the effluent pH. Oxygen-alkali pulping after steam explosion treatment of ${Na_2}{O_3}$-NaOH impregnated wood was shown that carbohydrate yield was very high because its effluent pH was increase from natural to mild alkali. Even if oxygen bleaching limit the delignification to 50% in order to avoid unacceptable yield and viscosity losses, oxygen-alkali pulping after steam explosion by ${Na_2}{O_3}$-NaOH impregnation was possible to extend the delignification more than 80%. Considering high pulp yield with lower lignin content from steam explosion treated wood, it might be profitable to end the cook at a high kappa number instead of a low kappa number, and continuously apply the oxygen delignification, in order to better quality pulp.

• Journal of Advanced Marine Engineering and Technology
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• 제22권1호
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• pp.100-107
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• 1998

Ventilation of the marine engine room is very important for the health of the workers as well as the nomal operation of machines. To find proper ventilation conditions of this engine room, numerical simulation with standard k-.epsilon. model was carried out. In the present study, the marine engine room is considered as a closed space with a heat source and forced ventilation ducts. The injection angle of air supply is found to be important. Injection with downword angle depresses recirculation flow, causing a strong steam in the wider space of the room. Ventilation and removal of the released heat are promoted with this pattern. There is a possibility of local extreme heating at the upper surface of engine when supply and exhaust ports of air are in bilateral symmetry. The effect of the increase of exhaust port area on ventilation decreases as the number of supply port increases.

• 한국도서관정보학회지
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• 제52권4호
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• pp.103-126
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• 2021

본 연구는 충청남도교육청 소속 19개 공공도서관을 대상으로 교육·문화복합공간으로서의 도서관 재구조화 방안을 제안하고자 하였다. 이를 위해 국내외 공공기관 복합화 시설의 사례 조사, 이용자 설문조사 등을 실시하였다. 그 결과 미래 공공도서관이 갖추어야 할 공간으로 배우는 공간(종합자료실, 테마 자료 탐구실, 미래교실, 블렌디드 러닝센터, STEAM 교육실, 원격강의학습실), 표현하는 공간(포이어, 메이커 룸, 디지털 매체 창작실, 원격강의제작실), 나누는 공간(동아리·모둠학습실, 웰빙 복합문화공간, 생활·편의공간, 휴게실·브라우징), 즐기는 공간(퍼포먼스·생각 놀이터, 유아·어린이 자료실, 디지털 가상체험실, 특화 알코브실, 야외독서실) 등으로 구분하여 공간 재구조화 전략을 제시하였다. 또한, 건축 규모, 장서 규모, 서비스 및 공간 수준 등을 고려하여 선도모형, 기본모형, 이음터 모형, 최소모형 등 도서관별로 특화된 교육청 소속 공공도서관의 재구조화 모형을 제안하였다.

• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.56-63
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• 2014

In this research, burst tests for axial notched steam generator tubes were conducted. To measure the burst pressure of notched tubes, a burst testing system was manufactured. The tests were conducted under internal pressure at room temperature. Part-through-wall and through-wall notches which have various geometries with different depths and lengths were machined by electro-discharged-machined(EDM) method. The burst pressure decreased exponentially with increasing notch length and decreased almost linearly with increasing notch depth. A comparison of the burst pressure with existing burst pressure solutions for cracked tube show that the existing solution agree well with the test results.

• 한국수소및신에너지학회논문집
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• 제31권5호
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• pp.411-418
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• 2020

A reformer is a device for producing hydrogen used in fuel cells. Among them, methanol steam reformer uses methanol as fuel, which is present as a liquid at room temperature. It has the advantage of low operating temperature, high energy density, and high hydrogen production. The purpose of this study is to improve the internal flow of the pressure vessel when a bundle of methanol steam reformer in the pressure vessel goes out to a single outlet. An analysis of equilibrium reaction to methanol steam reforming reaction was conducted using Aspen HYSYS^® (Aspen Technology Inc., Bedford, USA), and based on the results, computational analysis was conducted using ANSYS Fluent^® (ANSYS, Inc., Canonsburg, USA). For comparison of the results, the height of the pressure vessel, outlet diameter, and fillet was set as variables, and the optimum geometry was selected by comparing the effects of gravity and the amount of negative pressure.

• Corrosion Science and Technology
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• 제3권6호
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• pp.233-239
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• 2004

Primary water stress corrosion cracking of steam generator tubings occur on many tubes in pressurized water reactors(PWRs), and they are repaired using sleeves or plugs. In order to develop proper repair criteria, it is necessary to know the leak behavior of the tubes, which have stress corrosion cracks. Crack development tests were carried out on the tubes at room temperature, and leak rate and burst pressure were measured on the degraded tubes at room temperature and a high temperature. No leakage was detected on the tubes where 100 % through wall crack developed, at 1560 psi, which is an operating pressure difference of pressurized water reactors(PWRs). In some tests, leak rates of the tubes increased with time at a constant internal water pressure. A test tube showed a very small amount of leakage at 2700 psi in a high temperature pressure test at $282^{\circ}C$, but it disappeared after the pressure increased slightly. Even cracks are 100 % through wall, they need to open in order to reach a certain amount of leak rate at the operating pressure difference.