• Transactions of the Korean hydrogen and new energy society
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• v.31 no.5
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• pp.436-443
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• 2020

The performance prediction model of a solid oxide fuel cell stack has been developed using deep neural network technique, one of the machine learning methods. The machine learning has been received much interest in various fields, including energy system mo- deling. Using machine learning technique can save time and cost requried in developing an energy system model being compared to the conventional method, that is a combination of a mathematical modeling and an experimental validation. Results reveal that the mean average percent error, root mean square error, and coefficient of determination (R2) range 1.7515, 0.1342, 0.8597, repectively, in maximum. To improve the predictability of the model, the pre-processing is effective and interpolative machine learning and application is more accurate than the extrapolative cases.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.6 no.3
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• pp.359-368
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• 1999

Background : The purpose of this study was to determine whether cleansing the perineum and urethral meatus and using midstream urine affect the rate of bacterial contamination of urine specimens, and to determine the optimum urine collection method. We studied 41 asymptomatic healthy nursing school students. Women who were menstruating were not excluded from this study. Method : The first and midstream urine samples were collected during consecutive urinationsby each woman. The first sample was not a clean-catch specimen, and the second one was a clean-catch specimen. Both specimens were studied by urinalysis and bacterial culture with standard methods. Results : 41 women met the study criteria and 39 successfully completed the study. None of the urine cultures were positive. 68.3% of the non clean-catch first urine cultures, 53.7% of the non clean-catch midstream cultures, 33.3% of the first clean-catch urine culteres and 30.8% of the midstream clean-catch urine were found to be contaminated. There was a significant difference in the bacterial contamination rates between the first and midstream urine, and the clean-catch and non clean-catch urine(p=0.035, p =0.001 respectively). On urinalysis, 7.3% of the non clean-catch first urine, 7.3% of the non clean-catch midstream urine, 2.6% of the clean-catch first urine and 2.6% of clean-catch midstream urine were found to be above grade 2. Conclusions : According to our results, the bacterial contamination rate was the lowest in midstream and clean catch urine specimens. Threrfore it is recommended that the midstream clean-catch technique is the standard practice for collecting urine specimens for bacterial culture in women.

• Proceedings of the Safety Management and Science Conference
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• 2006.11a
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• pp.325-336
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• 2006

This research analyzes clean room major fire prevention standard of clean Room (FM, IRI, and NFPA Code), the structure of Performance-Based Fire Safety Design (PBD) applied the korean fire industry situation. Performance-Based Fire Safety can operate effectively the performance of fire protection equipment & building design, so the fitness of fire safety system can be embodied by operating this. moreover, cost to be consume fire safety of real building can reduce and Performance-Based Fire Safety is considered to important technique in fire protection field. A fire in a clean room may cause a serious loss by spreading smoke particles. We will be investigated by using a computational fluid dynamics, for loss prevention by smoke spreading from one fire area to another for clean room and compared the Performance-Based Fire Safety Design with the prescriptive code design. The methodology of fire safety performance-based fire safety design and guarantee of many kinds design skill of fire system and developing design procedure will be very serious one in order to improve efficiency of domestic system. Therefore, This research will be contributing to secure safety of clean room and to set up the performance-based fire safety design in Korea by regulation for the performance-based fire safety design effectively.

• Journal of the Korea Safety Management & Science
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• v.8 no.5
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• pp.211-229
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• 2006

This research analyzes clean room major fire prevention standard of clean Room(FM, IRI, and NFPA Code), the structure of Performance-Based Fire Safety Design(PBD) applied the korean fire industry situation. Performance-Based Fire Safety can operate effectively the performance of fire protection equipment & building design, so the fitness of fire safety system can be embodied by operating this. moreover, cost to be consume fire safety of real building can reduce and Performance-Based Fire Safety is considered to important technique in fire protection field. A fire in a clean room may cause a serious loss by spreading smoke particles. We will be investigated by using a computational fluid dynamics, for loss prevention by smoke spreading from one fire area to another for clean room and compared the Performance-Based Fire Safety Design with the prescriptive code design. The methodology of fire safety performance-based fire safety design and guarantee of many kinds design skill of fire system and developing design procedure will be very serious one in order to improve efficiency of domestic system. Therefore, This research will be contributing to secure safety of clean room and to set up the performance-based fire safety design in Korea by regulation for the performance-based fire safety design effectively.

• Clean Technology
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• v.3 no.2
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• pp.31-33
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• 1997

Nitrate contamination in surface water and ground water have increased in Korea. This trend has raised concern because nitrates caused methemoglobinemia in infants. To remove nitrates from waters, various purification processes including ion-exchange, biological denitrification, and chemical denitrification are currently in use for the treatment of water. However, little economically advantageous process exists for the industrial scale treatment of effluents highly polluted with nitrates. A new process has been developed for nitrate and other salts removal from polluted waters. Alumina cement and lime served as precipitating agents to remove nitrate with stirring at basic pH. Decreasing alumina content in alumina cement result in a increasing in nitrate removal yield. Stable removal of nitrate(1000mg/L) was readily achieved by two-stage removal process.

• Journal of the Korean institute of surface engineering
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• v.48 no.5
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• pp.194-198
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• 2015

A blade-abrading method was newly developed for the preparation of clean Mg alloy surface and reported for the first time in detail in this paper. The blade-abrading method includes abrading of the Mg alloy surface with a sharp blade or knife to remove the surface oxide and contaminants on the skin of Mg alloys mechanically, thereby providing very clean surface of Mg alloys. The clean surface prepared by the blade-abrading method in the air was found to be covered with thin and dense air-formed oxide films. Based on the experimental results obtained in this work, it is concluded that the newly developed blade-abrading technique is a very simple and useful pretreatment method which can provide clean and well-defined surface for the following surface treatments.

• 기계와재료
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• v.10 no.3 s.37
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• pp.71-77
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• 1998

• Proceedings of the KAIS Fall Conference
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• 2000.04a
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• pp.56-56
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• 2000

• Corrosion Science and Technology
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• v.21 no.5
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• pp.327-339
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• 2022

The water-jet technique started by Bridgman can cut metal and alloys without harmful gas and fume. However, while this technique is convenient to cut metals and alloys, in the case of coated pipe, water jet induces the degradation of coatings on the pipes, and may facilitate structural failure, leakage, and loss of products. While there are many reports on the effect of water jet on cut metals and the damage of metallic materials, research on the effect of water impingement on the epoxy coatings has been little studied. In this work, we therefore control the velocity of water jet, distance between nozzle and specimen, and water temperature, and discuss the effect of water impingement on the epoxy coatings. Increasing water velocity and water temperature and reducing nozzle distance increased the degradation rates of three epoxy coatings were increased. Among three test parameters - water velocity, nozzle distance and water temperature, water temperature was relatively effective to increase the degradation rate of epoxy coatings.

• Clean Technology
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• v.3 no.2
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• pp.87-93
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• 1997

A new process has been developed for nitrate and other salts removals from polluted waters. Alumina cement and calcium oxide served as precipitating agents to remove nitrate with stirring at basic pH. Low content of alumina in the commercialized alumina cements resulted in a increasing in nitrate removal yield. It is found that the compositions of aluminium and calcium are the most important factors in successful nitrate insolubilization. In order to remove high concentration of nitrate in polluted water, multi-stage precipitation was found to be very effective. Sulfate, chloride, and phosphate ions as well as nitrate were also removed by the precipitated reaction. After precipitation, post-treatments including Na2CO3 addition and neutralization with acid alleviated the level of aluminium and calcium in the treated water.