• Journal of the Korean Chemical Society
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• v.41 no.7
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• pp.329-336
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• 1997

Photoacoustic spectroscopy was utilized to investigate the carrier transport and the thermal diffusivity in GaAs and Si. From the frequency dependence of the photoacoustic signal, it is found that heat source was originated from the instantaneous thermalization process in low frequency region. In high frequency region, however, the heat was generated by the nonradiative bulk recombination and the nonradiative surface recombination processes. It was also shown that the photoacoustic effects in GaAs of a direct band gap were governed by all three processes and those in Si of an indirect band gap were produced by the instantaneous thermalization and the nonradiative bulk recombination only. The phase of the photoacoustic signal showed a minimum value in GaAs. In Si, the phase of the photoacoustic signal was monotonically decreased as the modulation frequency was increased, demonstrating the above-mentioned mechanisms of the generation of heat. By measuring the photoacoustic signal, thermal diffusivities of semiconductors were determined to be ∼0.35 ㎠/s for GaAs and ∼1.24 ㎠/s for Si. In addition, the similar values of thermal diffusivities were obtained from the curve fitting of photoacoustic phase spectra.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.5
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• pp.138-150
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• 2021

This study aims to understand the background and characteristics of the UK's allotments, as the UK is one of the nations participating in allotment invigoration. This study will focus on approaches to policy, active governance, and socioeconomic impact. To address this, allotment-related issues, policies since the beginning of the 19th century were analysed. In addition to this, Sheffield City, UK, was selected as a specific case to analyse the framework of allotment management, active governance concerning allotment management, and the residents' perceptions of allotments through a questionnaire survey. It was found first that the UK government, since 1806, has been consistently producing localism policies aiming to devolve management authority into local governments, which actively obtain sites for allotments. Secondly, the structure of allotment management formed in active governance leads the overall maintenance, partnership, income generation, and monitoring of the allotments. Interestingly, the structure of the department organisation of local government in Sheffield established the position of community manager, who encourages community invigoration. However, a gap between socioeconomic aspects was found in which the allotment invigoration in lesser deprived areas outweighs the invigoration in more deprived areas. In contrast, according to the questionnaire survey, respondents in more deprived areas were more likely to be involved in allotment activities and the community. The key to addressing the socioeconomic gap in the context of allotment invigoration is the adoption of the Public-Community-Private-Partnership framework. This will be of great importance to longer-term promotion of beneficial allotment practices.

• Membrane Journal
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• v.29 no.3
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• pp.147-154
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• 2019

The permeate flux increments of a natural convection instability flow (NCIF) caused by the change of inclined angles ($0{\sim}180^{\circ}$) to gravity of the commercial membrane module were tested in the dead-end membrane filtration of BSA protein solution. The NCIF are more generated as the inclined angle increased from $0^{\circ}$ to $180^{\circ}$, and the occurred NCIF enhances permeate flux. However, the commercial module can only generate NCIF by completely removing the air gap in module. Since the custom design module designed in this study is permeated in a crossward direction ($90^{\circ}$), NCIF is always generated even if there is the air gap in module. The results of membrane filtration of BSA and dextran solutions using a custom design module showed that the flux in the crossward direction is increased to about 3.8 times for BSA solution and 1.8 times for dextran solution after two hours of operation due to the occurrence of NCIF. Also, NCIF generation is continued during 20 hours filtration of BSA solution, increasing the permeate flux to about 7.5 times. Since the custom design module with a permeation in the crossward direction and NCIF is always generated within the module, so it is possible to expect an increase in permeate flux due to the suppression of fouling formation, and thus to be utilized as a superb dead-end membrane module.

• Journal of Korea Entertainment Industry Association
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• v.15 no.3
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• pp.193-202
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• 2021

The purpose of this study was to examine relation of awareness and education requirement of the 4th industrial revolution in health care students in attempt to provide basic data of determining the principle and education plan. The subject of study were 280 students of health department of H university in Gwangju and analyzed by gender and grade. The female students were positive awareness of the 4th industrial revolution and the level of influence on the major field was highest in lower grade students. The level of negative factors such as generation gap(p<0.05), gap between rich and poor (p<0.01), personal information infringement(p<0.05), decrease in existing jobs(p<0.05), and abuse of artificial intelligence(p<0.05) was highest in male students. In prepration for the 4th industrial revolution, education on bio and medical device(22.2%) was the most desired. The higher positive awareness, the higher educational demand(p<0.001). It is necessary to develop programs and various education to increase positive factors such as the creation of new jobs and improve the quality of life in the era of the 4th industrial revolution.

• Korean Chemical Engineering Research
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• v.61 no.1
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• pp.142-154
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• 2023

As the importance of the environment has been recognized worldwide, the need to calculate and reduce carbon emissions has been drawing an increasing attention throughout various industrial sections. Thereby the discipline of LCA (Life Cycle Assessment) involving raw material preparation, production processes, transportation and installation has been established. There is a clear research gap between the need and the practice for Korean Case of renewable energy industry, particularly wind power. To bridge the gap, this study conducted LCA research on wind power generation in the Korean area of Yeongdeok, an example of a domestic onshor wind power complex using SimaPro, which is the most widely used LCA system. As a result of the study, the energy recovery period (EPT) of one wind turbine is about 10 months, and the GHG emitted to generate power of 1 kwh is 15 g CO₂/kWh, which is competitive compared to other energy sources. In the environmental impact assessment by component, the results showed that the tower of wind turbines had the greatest impact on various environmental impact sectors. The experience gained in this study can be further used in strengthening the introduction of renewable energy and reducing the carbon emission in line with reducing climate change.

• Journal of the Korean Geographical Society
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• v.49 no.5
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• pp.728-746
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• 2014

The purpose of this study is to analyze the influence of the selective migration of young age group and the stage migration which has proceeded through generations, on the transition of fertility and the population growth in the rural and urban in the case of Jeollabuk-do. For this, we use O-D matrix of 20-34 age group, the distribution of that group and women of child bearing age, and vital statistics in 1970-2010. The major findings of this study are as follows. First, the outflows from their birth place are common and dominant features of 20-34 age group in each time. Second, there is the stage migration which preceding generation moved from the rural areas to the cities in Jeollabuk-do and following generation has moved from the cities to Seoul metropolitan area. Third the selective outflow migration of young age group has leaded to reduction of the childbearing population, declining birthrate, aging and natural population decline. Due to the stage migration, these depopulation processes occurred in rural area in the past, and currently it expands to the cities with about 15 years time gap. In fact, there have been the natural population decrease which annual number of deaths exceed that of births from the late 1980s in the most rural areas and in the early 2000s, such a phenomenon has been confirmed also in urban areas. Therefore, this study concludes that the stage migration through generations is one of the crucial factor to the population growth in local cities and also brings out the step-wise population decrease in settlement hierarchies.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3367-3378
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• 2021

The design phase and safety assessment of Generation IV liquid metal-cooled fast reactors calls for the improvement of fuel pin performance codes, in particular the enhancement of their predictive capabilities towards uranium-plutonium mixed oxide fuels and stainless-steel cladding under irradiation in fast reactor environments. To this end, the current capabilities of fuel performance codes must be critically assessed against experimental data from available irradiation experiments. This work is devoted to the assessment of three European fuel performance codes, namely GERMINAL, MACROS and TRANSURANUS, against the irradiation of two fuel pins selected from the SUPERFACT-1 experimental campaign. The pins are characterized by a low enrichment (~ 2 wt.%) of minor actinides (neptunium and americium) in the fuel, and by plutonium content and cladding material in line with design choices envisaged for liquid metal-cooled Generation IV reactor fuels. The predictions of the codes are compared to several experimental measurements, allowing the identification of the current code capabilities in predicting fuel restructuring, cladding deformation, redistribution of actinides and volatile fission products. The integral assessment against experimental data is complemented by a code-to-code benchmark focused on the evolution of quantities of engineering interest over time. The benchmark analysis points out the differences in the code predictions of fuel central temperature, fuel-cladding gap width, cladding outer radius, pin internal pressure and fission gas release and suggests potential modelling development paths towards an improved description of the fuel pin behaviour in fast reactor irradiation conditions.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.28 no.3
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• pp.95-120
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• 2023

Methane (CH₄) is a key greenhouse gas in the atmosphere with 85 times greater greenhouse potent relative to carbon dioxide (CO₂). The atmospheric concentration of CH₄ is rapidly increasing due to the intensive usage of CH₄ and the thawing of the cryosphere. Additionally, with the current warming of ocean water, the dissociation of gas hydrates, an ice-like compound and the largest reservoir of CH₄ on Earth, is expected to occur, resulting in the release of CH₄ from the seafloor into the overlying water and atmosphere. Moreover, bottom water hypoxia is another concern that potentially introduces greenhouse gases into the atmosphere. With ongoing global warming and eutrophication, the size and duration of bottom water hypoxia are rapidly increasing. These low-oxygen conditions would relocate the redox zone shallower in sediment or in the water column, causing the release of CH₄ into the atmosphere and thereby intensifying global warming. However, there exists a gap in the understanding of CH₄ dynamics including its generation in relation to bottom water hypoxia. Therefore, this review article aims to understand the relationship between CH₄ and bottom water hypoxia and to draw attention to CH₄ investigation in Korea.

• Korean Journal of Culture and Social Issue
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• v.23 no.4
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• pp.587-604
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• 2017

The purpose of this research is to analyze generation gap of positive effects on character strength for full life of adults in Korea and to verify mediating effect of volunteering from character strength in this roots. To test this effects, there was an investigated differences of perception on character strength, volunteering and full life from 1,405 Koreans. Then had set up the influence model of character strength on full life between generation, and verified the model through structural equation. Therethrough first, there was statistical significant between generations except the variables of trust, full life and meaning of life. Second, full life was positively influenced by character strength in early adulthood. Third, volunteering had fully mediated from character strength to full life in post middle aged adults, but had partially mediated in early adulthood. This will help acquaint us with importance of accompany with volunteering at character strength than character strength directly connects to full life. Based on these results, we are treated on importance of mediating volunteering effects and influences of character strengths on full life in Korean society.

• 한국노년학
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• v.31 no.3
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• pp.711-732
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• 2011

The purpose of this study is to understand the meaning and essence of aged life, which Korean elderly experience in real life and restructure them in the context of time and culture. In order to do so an in-depth interview was done with 15 elderlies over the age of 60 living in Hwaseong City, an urban-rural composite area in Gyeonggi Province where diverse elderlies could be found. In result, first, Korean elderly's understanding of aged life had physical, familial, economical, leisure, and social restoration aspects. Second, it was found that the degree of understanding about preparation for aging and preparedness is quite low. Third, as the gap between actual preparation for aging and aged life that elderly dreamed of became wider 'resentment on children', 'denial of reality', 'physical and economical change', and 'experience from prolongation of life-cycle' was found. Based on such results following suggestions could be made. First, the awareness of aged life and preparation for aging should be strengthened and there is a need for diverse educations aiming successful aged life. Second, elderly welfare policy and practical intervention with an integrated perspective based on the realm of life-cycle are demanded. Third, there is a need to strengthen the Aged Income Maintenance System for existing elder generation. Fourth, an intervention about adaptation and coping means of life event is needed. Lastly, there is a need to expand and carry out the aged life planning program for future elder generation.