• Korea journal of population studies
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• v.34 no.3
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• pp.55-84
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• 2011

This study initiated with the intention to reveal the social consultations and fissures through a comparative analysis on generational characteristics by indicating occupation-related identities with the concept of social identity supported by theoretical resources. According to the three dimensions of social identity which are evaluation, potency and activity, there was more generational agreement rather than difference toward occupation-related identities. Among the 44 identities, only evaluation dimensions on minister, congressman, plane captain, farmer and potency dimensions on CEO of a major companies, professor, medical doctor, nurse, celebrity, shaman, unemployed person were statistically significant. For 'Leader and Professional', the respondents in their 50's gave high scores in both evaluation and potency dimensions. On the other side, the 30's had negative viewpoints while the 20's and 40's had neutral perspectives. For the potency dimension, the age groups were divided into the 20's, 30's and 40's, 50's; having the younger generations underestimate the potency dimension of such categories. Also for the 'General Occupation', 20's and the 30's relatively devaluated with more distinctive degree toward evaluation dimensions. For religion, 20's and 30's were positive toward buddhist monks while the 40's and 50's were more favorable with priests. For the non-economically active population, the lifetime cycle influenced each generations. When performing a two dimensional analysis toward the 'Leader and Professional' with evaluation and potency on each axis, the 50's highly evaluated both evaluation and potency dimension of such identities. However, for the 40's, 30's and 20's, the average value fell while the focus of the distribution deepened. The 30's had negative perspective toward the evaluation dimension while the 20's reflected critical attitude toward the potency dimension.

• Journal of Korea Technology Innovation Society
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• v.15 no.4
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• pp.745-765
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• 2012

When attempting to use the income approach for the purpose of technology valuation, it is essential to identify the economic life of the technology in question. From the mid-2000s up to the present, the methods proposed by major Korean institutions for estimating the economic life of technologies have been based on cited patent life (CLT), which is one of the types of technology life. The present study utilizes cited patent life (CLT) to estimate the economic life of technology for the purpose of technology valuation, and proposes a new method of analyzing cited patent life, a method that has been improved by taking into consideration the elapsed period and the time period of investment required for commercialization, two factors which have been hitherto overlooked. Survival curve analysis is a method that has already been widely utilized to estimate the economic life of tangible assets, and this study applies the same method to the calculation of the cited patent life index of technology to provide a more objective method for determining the lifetime of a technology. The remaining life expectancy of cited patent life based on the number of elapsed years was calculated and used to determine the life expectancy of a technology that has reached a specific number of elapsed years, which is referred to as the remaining cited-patent life time (r-CLT).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.527-535
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• 2017

Heat management is one of the most critical issues in Polymer Electrolyte Membrane Fuel Cells (PEMFCs) installed inside the fuel cell power pack of a fuel cell battery hybrid UPS. If the heat generated by the chemical reaction in the fuel cell is not rapidly removed, the durability and performance of the fuel cell may be affected, which may shorten its lifetime. Therefore, the objective of this study is to select and propose a proper cooling method for the fuel cells used in the fuel cell power pack of a UPS. In order to find the most appropriate cooling method, the various design factors affecting the cooling performance were studied. The numerical analysis was performed by a commercial program, i.e., COMSOL Multiphysics. Firstly, the surface temperature of the 1 kW class fuel cell stack with the cooling fans placed at the top was compared with the one with the cooling fans placed at the bottom. Various rotation speeds of the cooling fan, viz. 2,500, 3,000, 3,500, and 4,000 RPM, were tested to determine the proper cooling fan speed. In addition, the influence of the inhaled air flow rate was investigated by changing the porous area of the grille, which is the entrance of the air flowing from the outside to the inside of the power pack. As a result, it was found that for the operating conditions of the 1 kW class PEMFC to be acceptable, the cooling fan was required to have a minimum rotating speed of 3500 RPM to maintain the fuel cell surface temperature within an acceptable range. The results of this study can be effectively applied to the development of thermal management technology for the fuel cells inside the fuel cell power pack of a UPS.

• Journal of Environmental Analysis, Health and Toxicology
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• v.21 no.4
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• pp.252-263
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• 2018

Distributions of 15 PAHs and 82 PCBs were investigated in sediment and fish samples collected from the Suyoung Estuary of Busan, one of the most urbanized and newly contaminated areas in Busan. The concentrations of $S_{15}PAH$ in sediments ranged from 17.9 to 777 ng/g-dry and were mainly originated from combustion processes. The concentrations of $S_{82}PCB$ in sediments ranged from 0.55 to 12.5 ng/g-dry and were significantly correlated with those of 12 dioxin-like PCBs and 6 non-dioxin like PCBs. Higher concentrations of PAHs and PCBs were found in the upper river and the inner Suyoung Bay than in marina and the outer Suyoung Bay. No sites exceeded the ecotoxicological values of PAHs and PCBs in marine sediments. Benzo[a]-pyrene was not detected in fish samples and the concentrations of $S_4PAH$ (0.15~0.45 ng/g-wet) were lower than the maximum level set by EU. The levels of PCBs in fish samples were at less than 1% of the Korean maximum level and 2% of the EU maximum level. The concentrations of dioxin-like PCBs were $0.01{\sim}0.32pg-TEQ_{WHO-2005}/g-wet$, and the highest concentration was found in eels, which were at less than 5% of the EU maximum level. Dietary intakes of PAHs and PCBs through fish consumption were estimated, and their lifetime cancer risk and non-cancer risk were much lower.

• Conservation Science in Museum
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• v.27
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• pp.23-38
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• 2022

The standing plaster figure entitled is an early work from Choi Man Lin's 'Eve' series. It reflects the aesthetics of abstract sculpture in the period following Korea's liberation from Japanese colonial rule. Modern and contemporary sculptures can be made from a wide variety of materials, so the particular selection of materials and expressive techniques are indicative of both the artist's intentions and the zeitgeist of the moment. In this regard, the materials and production techniques used in provide important basic data for the chronological study of Choi's artistic development. In this study, scientific analysis was conducted to reveal the production techniques used in the work. The scope of appropriate conservation treatment was decided through consultation between several people with decision-making authority. First, the internal structure was inspected using X-CT scanning, and a material analysis was conducted to identify the formal characteristics, materials, and production techniques found in the work. As the analyses revealed the work to be in a relatively stable state, only minimal conservation treatment was applied based on the opinions expressed by the institution housing the work, by a former assistant of the artist, and in an interview granted by the artist during his lifetime.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.85-89
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• 2021

AlGaN-based UV-C light-emitting diodes (LEDs) were applied for p-type activation by electrochemical potentiostatic activation (EPA). The p-type activation efficiency was increased by removing hydrogen atoms through EPA treatment using a neutral Mg-H complex that causes high resistance and low conductivity. A neutral Mg-H complex is decomposed into Mg^- and H⁺ depending on the key parameters of solution, voltage, and time. The improved hole carrier concentration was confirmed by secondary ion mass spectroscopy (SIMS) analysis. This mechanism eventually improved the internal quantum efficiency (IQE), the light extraction efficiency, the leakage current value in the reverse current region, and junction temperature, resulting in better UV-C LED lifetime. For systematic analysis, SIMS, Etamax IQE system, integrating sphere, and current-voltage measurement system were used, and the results were compared with the existing N₂-annealing method.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.6
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• pp.325-334
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• 2022

It has been more than 30 years since the term climate change began to become popular, but recently, rapid accelerated phenomena are appearing in the form of extreme weather all over the world. It is showing a distinctly different phenomenon from previous years, with heavy rain falling in the Death Valley desert in the U.S., and temperatures rising more than 40 degrees in Europe. In the Korean Peninsula, super typhoons with very strong wind speeds have become a major disaster risk for many years, and the supply of more energy due to the rise in sea temperature increases the possibility of super typhoons, requiring a proactive response. Unlike the method using numerical analysis, this study analyzed past typhoon data to study changes in typhoon characteristics for coastal disaster prevention. Existing studies have targeted all typhoons that have occurred, but in this study, a specific area was set up in the southern ocean of the Korean Peninsula and then a study was conducted. The subjects of the study were typhoons that occurred over the past 40 years from 1980 to the present, and it was confirmed that the maximum wind speed of typhoons affecting the Korean Peninsula increased slightly. The wind speed of typhoons in the specific area is about 80% of the maximum wind speed in their lifetime, and a correlation with ENSO could not be confirmed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.977-988
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• 2006

The goal of this study is to develop a realistic methodology for determination of the Life-Cycle Cost (LCC)-effective optimal seismic retrofit and maintenance strategy of deteriorating bridges. The proposed methodology is based on the concept of minimum LCC which is expressed as the sum of present value of seismic retrofit costs, expected maintenance costs, and expected economic losses with the constraints such as design requirements and acceptable risk of death. The proposed methodology is applied to the LCC-effective optimal seismic retrofit and maintenance strategy of a steel bridge considered as a example bridge in the accompanying study, and various conditions such as corrosion environments and Average Daily Traffic Volumes (ADTVs) are considered to investigate the effects on total expected LCC. In addition, to verify the validity of the developed methodology, the results are compared with the existing methodology. From the numerical investigation, it may be positively expected that the proposed methodology can be effectively utilized as a practical tool for the decision-making of LCC-effective optimal seismic retrofit and maintenance strategy of deteriorating bridges.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.04a
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• pp.9-10
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• 2000

An important business-field of world-wide steel-industry is the coating of thin metal-sheets with zinc, zinc-aluminum and aluminum based materials. These products mostly go into automotive industry. in particular for the car-body. into building and construction industry as well as household appliances. Due to mass-production, the processing is done in large continuously operating plants where the mostly cold-rolled metal-strip as the substrate is handled in coils up to 40 tons unwind before and rolled up again after passing the processing plant which includes cleaning, annealing, hot-dip galvanizing / aluminizing and chemical treatment. In the liquid Zn, Zn-AI, AI-Zn and AI-Si bathes a combined action of corrosion and wear under high temperature and high stress onto the transfer components (rolls) accounts for major economic losses. Most critical here are the bearing systems of these rolls operating in the liquid system. Rolls in liquid system can not be avoided as they are needed to transfer the steel-strip into and out of the crucible. Since several years, ceramic roller bearings are tested here [1.2], however, in particular due to uncontrollable Slag-impurities within the hot bath [3], slide bearings are still expected to be of a higher potential [4]. The today's state of the art is the application of slide bearings based on Stellite\ulcorneragainst Stellite which is in general a 50-60 wt% Co-matrix with incorporated Cr- and W-carbides and other composites. Indeed Stellite is used as the bearing-material as of it's chemical properties (does not go into solution), the physical properties in particular with poor lubricating properties are not satisfying at all. To increase the Sliding behavior in the bearing system, about 0.15-0.2 wt% of lead has been added into the hot-bath in the past. Due to environmental regulations. this had to be reduced dramatically_ This together with the heavily increasing production rates expressed by increased velocity of the substrate-steel-band up to 200 m/min and increased tractate power up to 10 tons in modern plants. leads to life times of the bearings of a few up to several days only. To improve this situation. the Mechanical Alloying (MA) TeChnique [5.6.7.8] is used to prOduce advanced Stellite-based bearing materials. A lubricating phase is introduced into Stellite-powder-material by MA, the composite-powder-particles are coated by High Energy Milling (HEM) in order to produce bearing-bushes of approximately 12 kg by Sintering, Liquid Phase Sintering (LPS) and Hot Isostatic Pressing (HIP). The chemical and physical behavior of samples as well as the bearing systems in the hot galvanizing / aluminizing plant are discussed. DependenCies like lubricant material and composite, LPS-binder and composite, particle shape and PM-route with respect to achievable density. (temperature--) shock-reSistibility and corrosive-wear behavior will be described. The materials are characterized by particle size analysis (laser diffraction), scanning electron microscopy and X-ray diffraction. corrosive-wear behavior is determined using a special cylinder-in-bush apparatus (CIBA) as well as field-test in real production condition. Part I of this work describes the initial testing phase where different sample materials are produced, characterized, consolidated and tested in the CIBA under a common AI-Zn-system. The results are discussed and the material-system for the large components to be produced for the field test in real production condition is decided. Outlook: Part II of this work will describe the field test in a hot-dip-galvanizing/aluminizing plant of the mechanically alloyed bearing bushes under aluminum-rich liquid metal. Alter testing, the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed. Part III of this project will describe a second initial testing phase where the won results of part 1+11 will be transferred to the AI-Si system. Part IV of this project will describe the field test in a hot-dip-aluminizing plant of the mechanically alloyed bearing bushes under aluminum liquid metal. After testing. the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed.

• Journal of dental hygiene science
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• v.11 no.3
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• pp.189-197
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• 2011

Objectives : The systematic health education to form the basic healthy lifestyle should be realized from elementary school, so oral health education at elementary school can determine the whole lifetime oral health. The elementary school health teacher's recognition and behavior who in charge of health promotion of students is important. Therefore, the study was conducted to enhance oral health education. Methods : Total 114 people among of 131 from health teacher Gwangju elementary school. Survey system is configured by referring to PRECEDE model. Results : In behavioral diagnosis the proportion of oral Health Education is less than 10%(58.8%), mostly educated in activity time (86.0%), the health teachers educate when it is needed(53.5%). In predisposing diagnosis in the eight areas of health education, the oral health education is ranked as fourth, fifth. Even in the next year project, the oral health education ratio was 21.9 percent. In enabling diagnosing every year the Oral health education training experienced rate is 13.2%, satisfaction rate is 33.3%. In reinforcing diagnosing disability element in the regular education course are the lack of oral health-related information (46.7%), lack of materials needed for education (30.6%), lack of training opportunities (21.4%). Conclusion : In further research, oral health education textbooks, materials and methods should be developed. At the foundation of there developments, the elementary oral health education program should be more fully developed and conducted and also the evaluation of its effectiveness will need.