• Journal of The Korean Association of Information Education
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• v.15 no.4
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• pp.551-560
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• 2011

STEAM education is a topic-based curriculum to integrate the concepts into other subjects such as science, technology, engineering, art and mathematics in order to improve the students' interesting, understanding, integrated thinking and problem solving ability. In this paper, we designed STEAM curriculum in the form of Project-based Learning and developed the material for elementary students. We also developed the android-based application through searching for a utilization of IT simulation for enhancement the students' Project-based Learning effect.

• Journal of the Korean Wood Science and Technology
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• v.20 no.3
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• pp.11-20
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• 1992

Steam explosion is one of the most effective pretreatment for fractionating wood. This leads to the total utilization of wood basic components; cellulose, hemicellulose and lignin. The amount of sugar and lignin extracted with the hot water method was very low. The lignin content of residues after extraction with using a sodium hydroxide treatment, increased delignification of carbohydrate as the concentration of alkali was increased. Oak, pretreated with steam exploded at 25kg/$cm^2$ for 6 min. then 1% alkali for 2hrs. showed a delignification rate up to 95%. A sodium chlorite treatment of steam exploded pine and oak also afforded a high deligninfication effect. Pine, treated 10% sodium chlorite for 2hrs. showed high delignification. However, by using a sodium hydroxide treatment, a 2% retreatment for Ihr. after a 2% for 2hrs. afforded remarkable delignification effect on exploded wood at 30kg/$cm^2$ for 9min. and at 35kg/$cm^2$ for 3-6min. In oak, an initial 2hrs. treatment of 2% sodium chlorite was followed by a second 2hrs. treatment at 10%. This showed a delignification rate of 96%.

• Journal of the Korean Wood Science and Technology
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• v.25 no.4
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• pp.68-74
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• 1997

This research was studied dissolving pulp for rayon production, which is not KP, SP methods but steam explosion and oxygen alkali treatment. The variation of characterization in wood cellulose after steam explosion and oxygen alkali treatment this follows. In the oxygen alkali treatment of exploded pine wood, yield of dissolving pulp was lower than steam-exploded oak wood, and we have obtained dissolving pulp that high purity cellulose, but degree of polymerization was inclined to decrease less than 200. In the case of steam-exploded oak wood, degree of polymerization was higher than steam-exploded pine wood but purity of cellulose was lower than its.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.613-616
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• 2007

A pilot scale circulating fluidized bed for refuse derived fuel is developed and constructed in order to demonstrate efficient and safe utilization of waste fuel. The capacity of the facility is 8 steam tons per hour with the steam quality of $450^{\circ}C$ and 38atm. The quantity and the quality of the produced steam is sufficient to produce 1MWe power capacity. The test operation proved the high combustion efficiency of 99% and up. The emissions of NOx, SOx in flue gas are below 100, 60ppm respectively with out any emission control. HCl emissions were above 400ppm at the combustor exit but reduced below 10ppm after scrubber.

• Advances in concrete construction
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• v.11 no.5
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• pp.367-374
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• 2021

The present study investigated the effect of the combined carbonation and steam curing on the physicochemical properties and CO₂ uptake of the Portland cement concrete. Four different curing regimes were adopted during the initial 10 h of curing to evaluate the potential of carbonation curing as an alternative to conventional steam curing in the precast concrete industry from environmental and practical viewpoints. Four combinations of carbonation and steam curing conditions were applied as curing regimes to the samples at an early age. The test results indicated that the samples treated with the combined carbonation and steam curing exhibited higher early strength development compared to the other samples, signifying that carbonation curing can reduce the production time of precast concrete. Furthermore, the CO₂ uptake capacity of the samples was calculated and found to be as high as 18% with respect to the mass of the paste samples. Hence, the simultaneous utilization of steam and CO₂ for the fabrication of precast concrete members has the potential to make precast concrete greener and more cost-effective.

• Korean journal of food and cookery science
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• v.29 no.4
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• pp.331-342
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• 2013

The purposes of this study were to identify the actual utilization condition of combi-steam ovens and to evaluate the importance and the satisfaction of dietitians and cooks who used the oven in school foodservice. A survey of 300 schools, 1 dietitian and 1 cook from each school respectively; total 600, was conducted and 202 completed questionnaires were available for the purpose of the statistical evaluation. The main results of this study were summarized as follows: Among the schools, 70.5% set up the oven during 2007~2009, the most commonly used cooking method was 'Baking (87.0%)' and the way of acquiring recipes for the oven was 'from oven manufacturing company (50.0%)'. The advantage of using the oven was 'the convenient use of the oven (63.3%)' and the disadvantage was 'Difficulty of cooking foods evenly (59.8%)'. The degree of importance and satisfaction on twenty six attributes were measured according to type of school, location of school, number of meal service per day, and number of total serving per day. Among quality attributes of importance of the oven utilization, 19/18 characteristics were assessed over 4 point (important) out of 5 scale by dietitians/cooks respectively and in satisfaction 16/18 were over 4 points (satisfied) by dietitians/cooks respectively. When it comes to the most satisfied factor of combi-steam oven, 'Improvement of cooking baked foods' was highest for dietitians (4.60 point) and 'Checking temperature of cooked foods' was for cooks (4.49 point). In overall satisfaction of the oven use, the average score was 4.10 point for dietitians, 3.98 point for cooks out of a 5 point scale. Using the survey results as a base, school foodservices are required to use the combi-steam oven efficiently to serve high quality of meals for students.

• Journal of Science Education
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• v.40 no.2
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• pp.166-188
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• 2016

The purpose of this study was to analyze the utilization of history of science and STEAM and the elementary school teachers' perceptions about design-based STEAM instruction applying the history of science in science class. To research the utilization of the history of science and STEAM in elementary science class, educational value of design-based STEAM instruction applying the history of science, the questionnaire was revised based on research conducted by Lee & Shin(2014), Park et al.(2010), Shin & Han(2011) and developed questionnaire a total of 20 questions. It was administered to reply the questionnaire to 201 teachers of elementary school in D and G area. The results of this study were as follows: elementary school teachers did not teach actively the history of science, made it read students by simply introducing himself. They did not teach actively STEAM due to not enough time(busy to take a magnitude). They were difficult to teach, but the most focused on the 'Creative Problem-solving' process. And elementary school teachers perceived positively about the educational value of design-based STEAM instruction applying the history of science. Especially, they perceived that it can help elementary school students find a hint for solving the problem through examples of cases of scientific principles and a scientist. In conclusion, it implicates that it is need to regard elementary school teachers' perceptions on application of the history of science and STEAM, and develop specific design-based STEAM program applying the history of science in order to be applied successfully in elementary school for the STEAM settlement.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.2
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• pp.169-176
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• 2020

There is a growing interest in hydrogen energy utilization since an alternative energy development has been demanded due to the depletion of fossil fuels. Hydrogen is produced by the reforming reaction of natural gas and biogas, and the electrolysis of water. An solid oxide electrolyte cell (SOEC) is reversible system that generates hydrogen by electrolyzing the superheated steam or producing the electricity from a fuel cell by hydrogen. If the water can be converted into steam by waste heat from other processes it is more efficient for high-temperature electrolysis to convert steam directly. The reasons are based upon the more favorable thermodynamic and electrochemical kinetic conditions for the reaction. In the present study, steam at over 180℃ and 3.4 bars generated from a boiler were converted into superheated steam at over 700℃ and 3 bars using a cylindrical steam superheater as well as the waste heat of the exhaust gas at 900℃ from a solid refuse fuel combustor. Superheated steam at over 700℃ was then supplied to a high-temperature SOEC to increase the hydrogen production efficiency of water electrolysis. Computational fluid dynamics (CFD) analysis was conducted on the effects of the number of 90° elbow connector for piping, insulation types and insulation layers of pipe on the exit temperature using a commercial Fluent simulator. For two pre-heater injection method of steam inlet and ceramic wool insulation of 100 mm thickness, the highest inlet temperature of SOEC was 744℃ at 5.9 bar.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.358-363
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• 1995

A study on passive cooling systems for concrete containment of advanced pressurized water reactors has been performed. The proposed passive containment cooling system (PCCS) consist of (1) condenser units located inside containment, (2) a steam condensing pool outside containment at higher elevation, and (3) downcommer/riser piping systems which provide coolant flow paths. During an accident causing high containment pressure and temperature, the steam/air mixture in containment is condensed on the outer surface of condenser tubes transferring the heat to coolant flowing inside tubes. The coolant transfers the heat to the steam condensing pool via natural circulation due to density difference. This PCCS has the following characteristic: (1) applicable to concrete containment system, (2) no limitation in plant capacity expansion, (3) efficient steam condensing mechanism (dropwise or film condensation at the surface of condenser tube), and (4) utilization of a fully passive mechanism. A preliminary conceptual design work has been done based on steady-state assumptions to determine important design parameter including the elevation of components and required heat transfer area of the condenser tube. Assuming a decay power level of 2%, the required heat transfer area for 1,000MWe plant is assessed to be about 2,000 ㎡ (equivalent to 1,600 of 10 m-long, 4-cm-OD tubes) with the relative elevation difference of 38 m between the condenser and steam condensing pool and the riser diameter of 0.62 m.

• Journal of the Korean Wood Science and Technology
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• v.20 no.4
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• pp.65-72
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• 1992

Steam defiberated pulp and steam exploded wood(birch chip) were extracted with solvents (hot-water, 1% NaOH, MeOH, hot water, 1% NaOH). The properties of residual fiber were examined for the utilization as ruminants feed. The digestibility is 38% in steam defiberated pulp(10kg /$cm^2$-15min) and 62-77% in exploded wood(17-18kg/$cm^2$-2~10min), respectively. The more steam pressure and time increase, the more the digestibility increase. The sugars obtained from extractives is amount from 7% to 13% in asplund pulp and from 7% to 10% in exploded pulp. The sugars was mainly composed of 70-80% xylose. The digestibility of residual fiber which is extracted with solvents is low than these of original fibers. Considering the yield and digestibility as ruminant feed, exploded pulp under 17kg /$cm^2$ for 10min has the best efficiency. The exploded wood gives 75.3% on yield(O. D. chip) and 48% on the digestibility.