• Membrane Journal
• /
• v.17 no.2
• /
• pp.81-92
• /
• 2007

Membrane-based separation processes are receiving increasing attention in the scientific community and industry since they provide a desirable alternative to processes that are not easy to achieve by conventional separation technologies. In particular, gas separation using polymeric membranes have annually grown so fast owing to advantages such as easy installation, no moving parts, small footprint and low energy process. The key element is definitely a polymer membrane exhibiting high permeability and high selectivity to compete with other gas separation technologies. Current polymer membranes used for commercial gas separation are a family of hydrocarbon polymers for hydrogen separation, air separation and carbon dioxide separation from natural gas sweetening. Relatively, gas or vapor separation properties of fluoropolymers are not known so much as compared with those of hydrocarbon polymers. Accordingly, in this study, membranes prepared from amorphous perfluoropolymers are of particular interest because of the unique properties of these polymers. The advantages offered by these amorphous perfluoropolymers for use in gas and vapor separation will be discussed. In addition, membrane properties and separation performance will be compared with other membranes available on the market.

• Korean Journal of Soil Science and Fertilizer
• /
• v.23 no.2
• /
• pp.94-99
• /
• 1990

A field experiment was conducted to study seasonal evapotranspiration above soybean canopy and its relationship with dry matter production by the Bowen ratio-energy balance method. The soybean "Paldalkong" was sown with the space of $47{\times}10cm$ at Suwon on May 27, 1988. The daily net radiation ranged from 59 to 76 percents of the total shortwave radiation under cloudless conditions, which was lower than cloud overcast condition with recorded 63 to 83 percents. The latent heat flux under overcast condition was sometimes larger than the sum of net radiation, implying transportation of energy by advection of ambient air. The linear relationship was obtained between daily or daytime net radiation and evapotranspiration. The evapotranspiration calculated by Bowen ratio-energy balance method was about 150 percent of class A pan evaporation during the growing season. The total solar radiation from June 20 to August 27 was $1043MJm^{-2}$. The 85 percent of the total shortwave radiation was used for evaporative heat. The dry matter production within the period was $836gm^{-2}$ and the water use efficiency was $2.31gDM\;kg^{-1}\;H_2O$.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.19 no.4
• /
• pp.589-609
• /
• 2017

This study carried out the density and energy dispersive X-ray spectroscopy and particle size analysis which are the physical characteristics of coal dust by collecting samples of coal dust in the five domestic mines to control the coal dust through ventilation in the workplace for coal mining in the country. This will contribute to a more comfortable working environment by understanding the physical characteristics of the coal dust which is derived from any hard coal produced domestically. In particular, the result of PSA analysis showed that the size of coal dust sample for this study ranged from $0.007{\sim}88.614{\mu}m$ were the particles less than $3.5{\mu}m$, the size range responsible for pneumoconiosis. To observe the flow of coal dust collected on the wind speed, the fallout of coal dust produced by the wind tunnel for the wind was measured and the particle size analysis of coal dust fallout was carried out. In addition, airborne dust is measured according to the mine velocity by using a multi-stage Anderson sampler in the mine where fine dust is generated in a large amount and the wind speed is found out to control the coal dust below $3.5{\mu}m$. In addition, natural ventilation pressure of A mine was calculated to prevent over design of the main fan.

• Geophysics and Geophysical Exploration
• /
• v.18 no.4
• /
• pp.223-231
• /
• 2015

Self-potential (SP) is sensitive to groundwater flow and there are many causes to generate SP. Among many mechanisms of SP, pore-fluid flow in porous media can generate potential without any external current source, which is referred to as electrokinetic potential or streaming potential. When calculating SP responses on the surface due to geothermal fluid within an engineered geothermal system (EGS) reservoir, SP anomaly is usually considered to be generated by fluid injection or production within the reservoir. However, SP anomaly can also result from geothermal water fluid within EGS reservoirs experiencing temperature changes between injection and production wells. For more precise simulation of SP responses, we developed an algorithm being able to take account of SP anomalies produced by not only water injection and production but also the fluid of geothermal water, based on three-dimensional finite-element-method employing tetrahedron elements; the developed algorithm can simulate electrical potential responses by both point source and volume source. After verifying the developed algorithm, we assumed a simple geothermal reservoir model and analyzed SP responses caused by geothermal water injection and production. We are going to further analyze SP responses for geothermal water in the presence of water production and injection, considering temperature distribution and geothermal water flow in the following research.

• Journal of the Korean Society of Food Culture
• /
• v.36 no.1
• /
• pp.92-102
• /
• 2021

There is little information on the nutrient intake according to the city size and small town in Korean elderly. This study analyzed the nutritional consumption of older people in metropolitan, middle and small cities, and rural areas according to four income levels. The recent data from the 2016~2018 Korean National Health and Nutrition Survey, Centers for Disease Control and Prevention were used. The final analysis included 4,325 individuals (Male: 1,856, Female: 2,469) over 65 years old. Multivariable regression with a complex sample design was conducted to compare the nutrient intake among the groups. In a comparison within regions, the nutrition status of the elderly in small towns was more vulnerable than metropolitan and middle & small cities. The energy intakes were similar between the groups. The carbohydrate intake of middle & small cities was significantly higher than the other regions. The intake of other nutrients in metropolitan and middle & small cities appeared to be higher than in rural areas. The number of nutrients with statistical significance between low and high-income levels were 19 in metropolitan, 11 in middle & small cities, and 5 in rural areas. Each contribution of carbohydrate, fat, and protein to the total energy intake was lower in the low-income level than the high-income level in metropolitan and middle & small cities. On the other hand, in rural areas, only the contribution of protein to energy intake was lower in the low-income level than the high-income level. Cities with higher levels of urbanization had more severe nutritional inequality in relation to the income level. There was also nutritional inequality present in rural areas but it was to a lesser extent. Moreover, the generally low level of nutrient intake was problematic in rural areas. These findings could be used as fundamental evidence for developing community nutritional policies for the elderly.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.8
• /
• pp.1050-1061
• /
• 2009

The present study was performed to evaluate energy and nutrients intakes of stroke patients in Daegu Gyeongbuk region, and to analyze the relative risk of stroke related to the intake levels of energy and nutrients. The case subjects (n=100) were selected from newly diagnosed stroke patients at Kyungpook National University Hospital. The control subjects (n=150) were selected from community residents who did not have stroke history and were sex and age-matched with the case subjects. The survey was conducted by individual interviews by trained dietitians using semiquantitative food frequency questionnaires. The odds ratios were calculated by using unconditional logistic regression. In male subjects, patient group had significantly higher consumption than the control group in mean daily intakes of energy, all energy yielding nutrients, vitamin $B_1$, $B_6$, niacin, folic acid, vitamin E, phosphorus, potassium, zinc and dietary fiber, and also in the ratio of energy intake from protein and fat. In women subjects, the patient group consumed significantly lower intakes than the control group in fat, vitamin C, folic acid, vitamin E, iron, but vice versa in carbohydrate energy ratio. As for men, the increased intakes of energy, protein, carbohydrate vitamin $B_1$, E and niacin, zinc, total fatty acids, monoand poly-unsaturated, n-6 fatty acids significantly raised the relative risk of stroke. As for women, the increased intakes of fat, vitamin A, $B_2$, $B_6$, niacin, vitamin C and E, iron, sodium, potassium, selenium, mono-, poly-unsaturated, n-6 fatty acids, cholesterol, taurine and dietary fiber significantly lowered the relative risk of stroke. The results of the study demonstrated that the effect of several nutrient intake levels, such as niacin, vitamin E and fatty acids, on the relative risk of stroke was inconsistent between sex. The reason for this sex difference needs to be elucidated in a larger scale study.

• The Korean Journal of Community Living Science
• /
• v.17 no.4
• /
• pp.151-161
• /
• 2006

This study was made to find out how health practice affect on nutrition status of the college freshmen in male and female. 400 freshmen students in 4year colleges were surveyed. Questionnaire and blood analysis were made. The contents of questionnaire contained general characteristics, health practice behavior, and food intake. The physical measurement included height, weight and blood pressure. The questions for health practice were about drinking, smoking, BMI, skipping breakfast and sleeping. Nutrient intake was expressed by DDS(Dietary Diversity Score by 5 food groups) and DVS (Dietary Variety Score) and 24-hrs recall method was used to find out the quantity of daily food intake. EAR% was calculated and NAR and MAR were produced. The results are as follows: 1) BMI was $22.77kg/m^2$ for males and $20.42kg/m^2$ for females. The ratio maintaining normal weight indicated by BMI of 18.5-23 was higher(p<0.001) for female students(63.2%) than males(56.5%). The ratio of overweight with over $23kg/m^2$ of BMI was 28.5% for males and 8.8% for females(p<0.001). 2)The ratio of drinking students was 59.4% for males and 40.6% for female(p<0.001). And the ratio of smoking students was 95.2% for males and 4.8% for females(p<0.001). 3) The ratio of poor health practice group was 35.7% for males and 25.5% for females, and that of excellent one was 25.4% for males and 33.1% for females(p<0.05). 4) In NAR, the lowest ratio was observed for the intake of Ca, Fe, Vitamin C and Vitamin $B_2$. The intake of Fe, Vitamin $B_2$ and phosphorus were different significantly according to sexuality. For Fe, female students showed lower level than male students(p<0.001). For Vitamin $B_2$, and phosphorus female students showed higher level(p<0.001). 5) In MAR, there was no difference according to sexuality in almost all of the ingredients. 6) For energy intake, male and female students showed 59% and 66% of EAR and it was insufficient for them. 7) For protein, more than 100% was obtained. The lowest ratio was observed for the intake of vitamin C 50.8%, Ca 53.6% and Fe 65.1% of EAR were obtained. The lowest intake ratio and for the intake of Fe female students obtained just 37.5% of EAR showing high risk of anemia. The intake of energy(p<0.001), phosphorus(p<0.01), niacin(p<0.05), Fe(p<0.001), and Vitamin $B_2$ (p<0.001) were different significantly according to sexuality. For Fe, female students showed lower level than male students(p<0.001). For energy, phosphorus, niacin, and Vitamin $B_2$ female students showed higher level(p<0.001) than male students. 8) For blood pressure, male students showed normal level of 120.7/79.1 mmHg, however, female students showed 114.5/75.4 mmHg lower than male (p<0.001). 9). In blood, for hemoglobin female students showed significantly lower level than that of male(p<0.001). T-Cholesterol and HDL-Cholesterol female students showed higher level than males (p<0.001), And for triglyceride male students showed higher level than females(p<0.001). Ca and Fe female students showed lower level (p<0.001).

• Korean Journal of Ecology and Environment
• /
• v.43 no.1
• /
• pp.55-68
• /
• 2010

The seasonal variation of microbial community, based on the bacteria, heterotrophic nanoflagellates (HNF), phytoplankton and ciliates, was investigated at three sites in the eutrophic brackish water of Lake Shihwa and its adjacent areas from May 2007 through May 2008. At the upstream-region site St. 1, compared to the other two sites, significantly lower salinities and higher concentrations of nutrients and chlorophyll $\alpha$ (Chl. $\alpha$) were recorded. The annual average abundances of bacteria at St. 1, St. 2 and St. 3 were $6.8{\times}10^6$, $7.4{\times}10^6$ and $4.6{\times}10^6\;cells\;mL^{-1}$, respectively. As for the annual average concentrations of HNF, $19{\times}10^2$, $6.7{\times}10^2$ and $5.9{\times}10^2\;cells\;mL^{-1}$, were recorded in St. 1, St. 2 and St. 3 respectively. The highest ciliate abundance appeared at St. 1 on 29 April, 2008 and in which, 99% were autotrophic ciliate Mesodinium rubrum (Myrionecta rubra). Significant linear correlations between the biomass of bacteria and Chl. $\alpha$ were found, however, no significant relationships between ciliates abudance/biomass and their prey organisms were detected in all three sites, implying relatively low energy transfer efficiencies between them. These results indicated that the trophic relationship between ciliates and their prey organisms in the microbial community might be influenced by indirect route since higher trophic level organisms did not directly correlate to those of lower trophic level, although high primary productions were detected in the eutrophic brackish water of Lake Shihwa and its adjacent areas.

• Korean Journal of Environment and Ecology
• /
• v.26 no.4
• /
• pp.537-549
• /
• 2012

The purpose of this study was to provide data for the basic research to found the effective conservation and management plan for the Hamyangsangrim designated as Natural Monument No. 154 and surround areas by analyzing the ecological characteristics such as landuse and actual vegetation, plant community structure, soil chemical property and also to identify the tendency of the ecosystem changes through comparison with past studies. According to analysis the results, the landuse and actual vegetation of survey site was classified as 8 types which were forest, artificial greenspace, plaza and open-space, bare ground and the pavement, water bodies, facilities, agricultural land and etc.. It was also categorized as 38 types according to detailed characteristic. 15 kinds of forest vegetation community types comprising silva were classified among them. The changes of actual vegetation showed little variation that the Quercus serrata-Carpinus tschonoskii forest was the most widely distributed in 2003(forest area ratio is 48.3%) and 2010(forest area ratio is 48.1%), whereas, the Quercus serrata forest declined a more dramatic from 11.6% to 23.2%. The Quercus serrata-Carpinus tschonoskii forest increased sharply(11.6% ${\rightarrow}$ 23.2%) and also the Quercus serrata-Zelkova serrata forest increased steadily(2.2% ${\rightarrow}$ 7.9%). The agricultural land around forest was transformed into artificial green zone. Moreover, water bodies, bare ground and the pavement of areas have increased. In addition, the urbanized area has decreased because the damaged areas inside forest have been restored to the woodlands. According to the result of typical 6 types vegetation communities change, the middle layer trees grew up to the canopy layer trees and was formed the canopy layer structure. The middle layer trees expanded their forces widely. Also new species appeared. And the shrub individuals also more dramatically increased due to the growth of shrubs. The force of Quercus serrata declined as well. However the force of Carpinus tschonoskii and Zelkova serrata expanded and increased in the forest. It must be the result of the ecological vegetation succession and environmentally soundly health recovery by influence of the projects of forest surrounding environment improvement and limitation of access to forest have managed and maintained since 2003. Those sorts of changes seems to be going to develop continuously. In the future Carpinus tschonoskii and Zelkova serrata will not be only codominant in the canopy layer but also Carpinus Tschonoskii, Zelkova serrata, Meliosma myriantha, Sapium japonicum. Styrax obassia and Acer pseudo-sieboldianum will be codominant in the middle layer. As a result, the forest's codominance species are going to be changed such like that.

• Korean small business review
• /
• v.33 no.4
• /
• pp.77-93
• /
• 2011

Since 2000, the employment rate of small and medium enterprises (SMEs) has dwindled while the creation of new jobs and the emergence of healthy SMEs have been stagnant. The fundamental reason for these symptoms is that the economic structure is disadvantageous to SMEs. In particular, the greater gap between SMEs and large enterprises has resulted in polarization, and the resulting imbalance has become the largest obstacle to improving SMEs' competitiveness. For example, the total productivity has continued to drop, and the average productivity of SMEs is now merely 30% of that of large enterprises, and the average wage of SMEs' employees is only 53% of that of large enterprises. Along with polarization, rapid industrialization has also caused anti-enterprise consensus, the collapse of the middle class, hostility towards establishments, and other aftereffects. The general consensus is that unless these problems are solved, South Korea will not become an advanced country. Especially, South Korea is now facing issues that need urgent measures, such as the decline of its economic growth, the worsening distribution of profits, and the increased external volatility. Recognizing such negative trends, the MB administration proposed a win-win growth policy and recently introduced a new national value called "ecosystemic development." As the terms in such policy agenda are similar, however, the conceptual differences among such terms must first be fully understood. Therefore, in this study, the concepts of win-win growth policy and ecosystemic development, and the need for them, were surveyed, and their differences from and similarities with other policy concepts like win-win cooperation and symbiotic development were examined. Based on the results of the survey and examination, the study introduced a South Korean model of win-win growth, targeting the promotion of a sound balance between large enterprises and SMEs and an innovative ecosystem, and finally, proposing future policy tasks. Win-win growth is not an academic term but a policy term. Thus, it is less advisable to give a theoretical definition of it than to understand its concept based on its objective and method as a policy. The core of the MB administration's win-win growth policy is the creation of a partnership between key economic subjects such as large enterprises and SMEs based on each subject's differentiated capacity, and such economic subjects' joint promotion of growth opportunities. Its objective is to contribute to the establishment of an advanced capitalistic system by securing the sustainability of the South Korean economy. Such win-win growth policy includes three core concepts. The first concept, ecosystem, is that win-win growth should be understood from the viewpoint of an industrial ecosystem and should be pursued by overcoming the issues of specific enterprises. An enterprise is not an independent entity but a social entity, meaning it exists in relationship with the society (Drucker, 2011). The second concept, balance, points to the fact that an effort should be made to establish a systemic and social infrastructure for a healthy balance in the industry. The social system and infrastructure should be established in such a way as to create a balance between short- term needs and long-term sustainability, between freedom and responsibility, and between profitability and social obligations. Finally, the third concept is the behavioral change of economic entities. The win-win growth policy is not merely about simple transactional relationships or determining reasonable prices but more about the need for a behavior change on the part of economic entities, without which the objectives of the policy cannot be achieved. Various advanced countries have developed different win-win growth models based on their respective cultures and economic-development stages. Japan, whose culture is characterized by a relatively high level of group-centered trust, has developed a productivity improvement model based on such culture, whereas the U.S., which has a highly developed system of market capitalism, has developed a system that instigates or promotes market-oriented technological innovation. Unlike Japan or the U.S., Europe, a late starter, has not fully developed a trust-based culture or market capitalism and thus often uses a policy-led model based on which the government leads the improvement of productivity and promotes technological innovation. By modeling successful cases from these advanced countries, South Korea can establish its unique win-win growth system. For this, it needs to determine the method and tasks that suit its circumstances by examining the prerequisites for its success as well as the strengths and weaknesses of each advanced country. This paper proposes a South Korean model of win-win growth, whose objective is to upgrade the country's low-trust-level-based industrial structure, in which large enterprises and SMEs depend only on independent survival strategies, to a high-trust-level-based social ecosystem, in which large enterprises and SMEs develop a cooperative relationship as partners. Based on this objective, the model proposes the establishment of a sound balance of systems and infrastructure between large enterprises and SMEs, and to form a crenovative social ecosystem. The South Korean model of win-win growth consists of three axes: utilization of the South Koreans' potential, which creates community-oriented energy; fusion-style improvement of various control and self-regulated systems for establishing a high-trust-level-oriented social infrastructure; and behavioral change on the part of enterprises in terms of putting an end to their unfair business activities and promoting future-oriented cooperative relationships. This system will establish a dynamic industrial ecosystem that will generate creative energy and will thus contribute to the realization of a sustainable economy in the 21st century. The South Korean model of win-win growth should pursue community-based self-regulation, which promotes the power of efficiency and competition that is fundamentally being pursued by capitalism while at the same time seeking the value of society and community. Already existing in Korea's traditional roots, such objectives have become the bases of the Shinbaram culture, characterized by the South Koreans' spontaneity, creativity, and optimism. In the process of a community's gradual improvement of its rules and procedures, the trust among the community members increases, and the "social capital" that guarantees the successful control of shared resources can be established (Ostrom, 2010). This basic ideal can help reduce the gap between large enterprises and SMEs, alleviating the South Koreans' victim mentality in the face of competition and the open-door policy, and creating crenovative corporate competitiveness. The win-win growth policy emerged for the purpose of addressing the polarization and imbalance structure resulting from the evolution of 21st-century capitalism. It simultaneously pursues efficiency and fairness on one hand and economic and community values on the other, and aims to foster efficient interaction between the market and the government. This policy, however, is also evolving. The win-win growth policy can be considered an extension of the win-win cooperation that the past 'Participatory Government' promoted at the enterprise management level to the level of systems and culture. Also, the ecosystemic development agendum that has recently emerged is a further extension that has been presented as a national ideal of "a new development model that promotes the co-advancement of environmental conservation, growth, economic development, social integration, and national and individual development."