• Journal of Environmental Health Sciences
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• v.20 no.4
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• pp.98-117
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• 1994

To provide data for the contents regarding environmental health (environmental hygiene, environmental pollution) in the textbooks of primary, middle and high schools, a total of 243 textbooks was analysed for two months from May, to July 31, 1993. Among the total 52844.50 pages, 1.65% was related to the environmental health, which account for 870.00 pages. In the textbooks by school level, the rate of the contents regarding environmental health in primary school was 1.63% (148.75 pages). that of middle school was 1.96% (243.25 pages) and that of high school was 1.53% (478.00 pages). The area of environmental hygiene was 0.24% (129.25 pages) and that of environmental pollution was 1.40% (740.75 pages) which is slightly high. In the field of environmental hygiene, the rate of the contents in the middle school textbooks was 0.53% which was the higher than that of the primary and high school textbooks. The rate of environmental pollution area was not significantly different by school level but the number of the pages was the higher at the high school than that of the primary and middle schools, which account for 428.8 pages. The contents related by the areas were as follows: 1. Contents related to environmental hygiene 1) Among environemtnal hygiene contents, the rate of housing sanitation was the highest as 0.14% (73.00 pages), that of air environment was 0.06% (33.00 pages) and that of water supply sanitation was 0.03% (17.25 pages). The portion of air environment was 5.00 pages in the primary school textbooks and that of housing sanitation at the middle and high schools was each 35.0 pages, 35.50 pages, which was the more than that of other fields. By school year, there was no contents related at the 1st and 2nd grades but were 4.75 pages at the 4th grade which were the more than those of other grades. At the 5th grade, water supply sanitation part was found but not air environment. Housing sanitation was found at the 3rd, 5th grades and insect or rodent control was at the 3rd, 4th, 5th, 6th grades. 2) In the middle school textbooks related to environmental health, 41.0 pages were included in the textbooks of pysical education, the highest number. The next was 19.5 pages in home economics, 2.8 pages in social studies and 3.00 pages in others. The contents of air environment were found in the textbooks of physical education and science, those of water supply and housing sanitation were in home economics and physical education and those of insect control were found 0.5 pages in home economics only. 3) In the high school textbooks, the highest number was 27.8 pages of home economics and the next was 11.5 pages of others, 7.8 pages of physical education, 2.0 pages of science and 0.3 pages of social studies. Air environment parts were included in the textbooks of science, physical education and home economics and water sanitation was in home economics, physical education and others. Housing sanitation was showed in home economics and social studies, on the other side the contents of insect or rodent control was found in home economics and physical education. 4) By the subjects related to environmental hygiene in the primary, middle and high school textbooks, 51.0 pages of home economics were the highest portion. It was also revealed that 49.5 pages of physical education, 14.5 pages of others, 13.5 pages of science and 0.8 pages of social studies were included. The number of 33.0 pages of air environment portion was distributed into 9.75 pages of science, 19.0 pages of physical education and 4.25 pages of others. Among 17.3 pages of water sanitation, 3.5 pages of home economics, 11.3 pages of physical education and 2.5 pages of others were included. Housing sanitation portions were 73.0 pages, which were distributed into 46.5 pages of home economics, 0.5 pages of social studies, 18.3 pages of physical education and 7.8 pages of others. 5) The number of photo, figure, illustration and table related in the primary school textbooks was 31. Among them, the number of photos was 21, that of figures or illustrations was 9 and that of table was 1. The number of 63 in the middle school textbooks was classified into 3 photos, 32 figures or illustrations and 28 tables. At the high school, the number of 56 was included 2 photos, 41 figures or illustrations and 13 tables.2. Contents related to environmental pollution 1) In the field of environmental pollution, the rate of water pollution was 0.39% (203.3 pages), that of air pollution was 0.31% (161.5 pages) that of soil pollution was 0.1% (57.3 pages), that of refuse disposal was 0.08% (40.3 pages) and others was 0.5% (278.5 pages) by school level, the rate of water pollution in the primary, middle and high schools was each 40.5, 48.0, 118.8 pages and that of air pollution was each 20.8, 38.3, 102.5 pages. 2) Environmental pollution areas were not inserted in the textbooks at the 1st grade of the primary school but foqnd 5.5 pages at the 2nd grade, 30.5 pages at the 4th grade, 36.3 pages at the 5th grade and a,9.5 pages at the 6th grade. Water pollution was included from the 2nd grade, air pollution and refuse disposal from the 3rd grade and soil pollution from the 5th grade. 3) In the middle school textbooks, environmental pollution was distributed into 90.25 pages of science, 42.8. pages of physical education, 20.5 pages of social studies, 19.5 pages of others and 4.0 pages of home economics. At the high school, the contents were found 191.3 pages in science, 119.3 pages in others, 88.5 pages in social studies, 28.5 pages in physical education and 1.3 pages in home economics. 4) By subjects of the primary, middle and high schools, the portion of environmental pollution was classified into 322.2 pages of science, 195.0 pages of social studies, 138.8 pages of others, 76.3 pages of physical education and 8.5 pages of home economics. Air and soil pollution parts were not found in the subjects of home economics. 5) The number of photo, figure or illustration and table related in the primary school textbooks was 218. Among them, the number of photos was 61, that of figures or illustrations was 149 and that of tables was 8. At the middike school, the number of 153 was distributed into 99 photos, 34 figures or illustrations and 20 tables. The number of 129 found in the high school textbooks was included 129 photos, 73 figures or illustrations and 100 tables.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.111-117
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• 2003

The present study discusses about the combustion and thermal flow characteristics of a G+R type incinerator, which is under construction for MAPO Incineration system, to evaluate the effects of various operating and design parameters. A bed combustion model is developed to simulate the waste bed combustion on the stoker. The effects of waste composition and primary air distribution are estimated. The results of the waste bed combustion model is applied to CFD(computational fluid dynamics) simulation, which simulates the detail of the thermal flow in the combustion chamber. The effects of bypass damper opening ratio, primary air distribution, and secondary air jet configuration are discussed.

• Journal of Industrial Technology
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• v.36
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• pp.3-7
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• 2016

The change of flue gas residence time with the location of air inlet in an incinerator is analysed. An independent numerical variable is the location of air inlet and dependant is the residence time of flue gas. The mean value of turbulence energy in a primary combustion chamber is also analysed. The flow field and the distribution of turbulence energy are investigated to evaluate their influence on the residence time of flue gas and the turbulence energy. As the position of secondary air inlet approaches to the top of primary combustion chamber, the residence time of gas and the turbulence energy become longer and larger respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.251-253
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• 2017

Numerical study of air-blast type injector for low emission aircraft engines was conducted. Volume-of-fluids approach was used to track interface of fuel and air. Primary atomization of fuel stream was visualized, and thickness and mean velocity at the injector exit was calculated. Liquid fuel injected from fuel slots joined together as a thin film on preflimer surface, and interacted with swirling air. As instability on the fuel surface increased, separation of fuel as ligaments and droplets occured. The film thickness and velocity were used to as fuel injection boundary condition for reactive flow simulation. Primary reaction zone was formed in vicinity of the fuel nozzle, creating a stable flame inside the combustor.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.3
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• pp.55-64
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• 2013

As the price competition between airlines became increasingly intensified, due to increased participation of low-cost carriers in the air transport industry and the continued deregulation of international air transport, each airline has introduced various management techniques for securing international competitiveness and operational efficiency in order to cope with the uncertainty in air transport industry. The world leading LCCs, such as Ryan air, easyJet and Southwest, have changed their traditional business models by increasing operation to primary airports, diversifying operating routes, making strategic alliances with FSCs or other LCCs, increasing the operations on the mid or long distance routes, expanding ancillary revenues, etc. As Korea's air transport industry is confronting with intense competition, our LCCs are requested to adjust to this new challenging situation. As the world leading LCCs did, Korean LCCs are recommended to adopt new business models such as restructuring of the air transport industry through M&A, operating more flexibly in terms of frequency or route, launching of services to primary airports, making strategic alliances with foreign FSCs, developing of 4th or 6th traffic demands, etc.

• Journal of the Korean Society of Safety
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• v.15 no.3
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• pp.30-39
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• 2000

The present paper deals with the numerical simulation for the spray characteristics with swirling turbulent flows and dilution flows from swirl injectors in a simplified can type of gas turbine combustor. The main objective is to investigate the characteristics of swirling turbulent flows with dilution flows and to provide the qualitative results for the spray characteristics such as the droplet distribution and Sauter Mean Diameter(SMD). The gas-phase equations based on Eulerian approach were discretized by Finite Volume Method, together with SIMPLE algorithm and the Reynolds -Stress-Model. The liquid-phase equations based on Lagrangian method were used to predict the droplet behavior. The results of preliminary test are generally in good agreement with experimental data, and show that the anisotropy exists in the primary zone due to swirl velocity and injected air from primary injector, and then gradually decays due to turbulent mixing and consequently near-isotropy occurs in the region between primary and dilution zones. For the spray characteristics, it is indicated that the swirling flows of primary jet region increase the droplet atomization. In addition, it is showed that the swirling flows at the inlet region lead the air-fuel mixture to be distributed near the igniter and can significantly affect the spray behavior in the primary jet region.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.210-216
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• 2002

Air abrasion technology can prepare enamel and dentin for bonding, similar to etching by acidic gels and solutions. Longer treatment can excavate pit and fissures, preparing the tooth for immediate placement of bonded resin materials. Although not appropriate for every clinical situation, the air abrasive technology minimizes heat, vibration and bone-conducted noise associated with conventional means of caries removal since the cutting is accomplished by air pressure. Also, patients treated with the air-abrasion technology rarely request anesthesia. Air abrasion technology was more effective in treating early carious lesions and stains compared to lesions where caries had already progressed to produce soft dentin and the strong air stream and noise caused by the evacuation system was a major discomfort to pediatric patients, and the experience and skillfulness of clinician should be required for accurate and proper tooth preparation.

• Journal of The Korean Association For Science Education
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• v.17 no.3
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• pp.239-249
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• 1997

Primary students' conceptions on the atmospheric pressure and its related concepts were investigated. Samples consisted of 41 5th grade and 43 6th grade primary school students. Two types of research methods were used: 1) the open-ended written questionnare;2) paper-pencil test. Naive theories on the atmospheric pressure and its related concepts were numerous. For example, 80% students thought that as we go higher into the atmosphere, the atmospheric pressure becomes greater. Also, 50% students thought that the hot air had greater the atmospheric pressure than the cold air. This study was also discussed the teaching strategies to overcome these naive theories on the atmospheric pressure and its related concepts.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.884-891
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• 2007

Comparing with the conventional transformer without the air gap, a contact-less transformer with the large air-gap (4.8cm) between the long primary winding and the secondary winding has the increased leakage inductance and the reduced magnetizing inductance. By the increased leakage inductance and the reduced magnetizing inductance on the primary of the contact-less transformer, a good deal of the primary current circulates through magnetizing inductance, which results in a massive loss and the high voltage gain characteristics for load variations in contact-less power supply (CPS). To consider these characteristics, in this paper, the efficiency characteristics of the contact-less power supply using a series resonant converter is presented, described and verified through theoretical analysis, computer simulation and experimental test of 2.5kW prototype.

• Journal of Korea Multimedia Society
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• v.22 no.10
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• pp.1187-1198
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• 2019

In this study, we propose a new $PM_{10}$ forecasting model for Seoul region using DNN(Deep Neural Network) and secondary data. The previous numerical and Julian forecast model have been developed using primary data such as weather and air quality measurements. These models give excellent results for accuracy and false alarms, but POD is not good for the daily life usage. To solve this problem, we develop four secondary factors composed with primary data, which reflect the correlations between primary factors and high $PM_{10}$ concentrations. The proposed 4 models are A(Anomaly), BT(Back trajectory), CB(Contribution), CS(Cosine similarity), and ALL(model using all 4 secondary data). Among them, model ALL shows the best performance in all indicators, especially the PODs are improved.