• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.532-542
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• 2018

Because maglev trains have a propulsion and absorption force without contact with the rails, they can drive safely at high-speed with little oscillation. Recently, test model of a maglev propulsion train was produced and operated, and has since been chosen as a national growth industry in South Korea; there have been many studies and considerable investment in these fields. This study examined the dynamic responses due to bridge-maglev train interaction and basic material to design bridges for maglev trains travelling at high-speed. Depending on the major factors affecting the dynamic effects, the scope of this study was restricted to the relationship between dynamic responses. A concrete box girder was chosen as a bridge model and injured train and rail types in domestic production were selected as the moving train load and guideway analysis model, respectively. From the analysis results, the natural frequency of a bridge for a maglev train, which has a deflection limit L/2000, was higher than those of bridges for general trains. The dynamic responses of the girder of the bridge for a maglev train showed a substantial increase in proportion to the velocities of the moving train like other general bridge cases. Maximum dynamic response of the girder is shown at a moving velocity of 240km/h and increased with increasing moving velocity of train. These results can be used to design a bridge for maglev propulsion trains and provide the basic data to confirm the validity and verification of the design code.

• The Korean Journal of Mycology
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• v.9 no.2
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• pp.93-97
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• 1981

The new strains of Mycogone perniciosa which could attack cream colored mushroom were collected and tested to find out their characteristics in comparison with the original strains. The optimum temperature for mycelial growth was $25^{\circ}C$, showing no difference between strains, but optimum pH was 6.0 for the original strains and pH 7.0 for the new ones. New strains did not survive at $50^{\circ}C$ for 60 minutes while original ones 40 minutes. Delan and Hamai were effective for controlling new strains and the mushroom strains which have scales showed resistance to the new strains of Mt. perniciosa regardless of the mushroom colors.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.330-348
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• 2007

Soil problems and agricultural water management of the reclaimed land in Korea were reviewed through research results conducted in RDA and ADC. According to the Korean Soil Classification and Soil Survey(NIAST, 2002), the 5 soil orders with the 45 soil series were distributed on the fluvio-marine or marine deposit of the west and south coastal plains. Yeompo, Munpo, Hasa, Gwangwhal, and Poseung soil series were most commonly distributed soil on the fluvio-marine deposits, associated with tideland of the sea coast. Former 4 soils were Entisols, and the latest one was the Inceptisols. Buyong soil associated with Poseung series was an Alfisols. Extent of Myeongji soil, a Molisols, and Yongho soil, a Histosol, were minor. Salinity control and management problems were closely related with high water table and low percolation rate due to plow-pan layer developed during the leaching process in the silty textured soil. For evaluation of field salinity, use of an electromagnetic inductance, EM38, with GPS was helpful to understand salinity status and field variability. Deep plowing, subsoiling and drainage improvement by tile drainage might be effective in paddy with plow-pan. New technology such as variable rate fertilization might save fertilizers and thus reduce environmental impact of agriculture on water quality. Water quality of agricultural water resources in reclaimed land was less adequate than that of inland water resources. Proper crop management is necessary depended upon quality for crop growth as well as to match with water quality target.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.4
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• pp.271-281
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• 2004

Adenoid cystic carcinoma is malignant tumor in salivary gland, and its behavior is very invasive. Of all malignant tumor adenoid cystic carcinoma is occured in frequency of 4.4% in major salivary gland, and 1.29% in minor salivary gland. Histopathologically, adenoid cystic carcinoma is characterized by a cribriform appearance, and tubular form and solid nest type tumor can be seen. The tumor cell structure composed of modified myoepithelial cell, and basaloid cell. Extracellular matrix of this tumor cell contains variable ground substance with basement membrane component. Basement membrane matrix composed of collagen fibers, glycoproteins, proteoglycans, and its function is well known that it participate in differentiation, proliferation, and growth of tumor cell. Basement membrane molecule is essential for invasion of peripheral nerve, blood vessel, skeletal muscle in tumor cell of adenoid cystic carcinoma. In many studies, the tumor cell of adenoid cystic carcinoma containing modified myoepithelial cell participate in synthesis of proteoglycan. In this study, tissue sample of adenoid cystic carcinoma of human salivary gland were obtained from 15 surgical specimen, and all specimen were routinely fixed in 10% formalin and embedded. Serial $4-{\mu}m$ thick sections were cut from paraffin blocks. the histopathologic evaluation was done with light microscopy. And, the immunohistochemical staining, characteristics of glycosaminoglycan were observed. For biochemical analysis of glycosaminoglycan, isolation of crude glycosaminoglycan from tumor tissue and Western bolt analysis were carried out. With transmission electomicroscopy, tumor cell were observed. Biologic behavior of adenoid cystic carcinoma was observed with distribution and expression of basement membrane of glycosaminoglycan in tumor cells, The results obtained were as follows: 1. In immunohistochemical study, chondroitin sulfate is postively stained in tumor cell and interstitial space, dermatan sulfate is weakly stained in ductal cell. But keratan sulfate is negatively stained. 2. In immunohistochemical study, heparan sulfate is strong positive stained in tumor cell and basement membrane, especially in invasion area to peripheral nerve tissue. 3. In transmission electromicroscpic view, the tumor cells are composed modifed myoepithelial cells, and contains many microvilli and rough endoplasmic reticulum. 4. In Western blot analysis, the expression of glycosaminoglycan is expressed mostly in heparan sulfate. From the results obtained in this study, tumor cell of adenoid cystic carcinoma is composed modified myoepithelial cell, and glycosaminoglycan of basement membrane molecule of heparan sulfate and chondroitin sulfate mostly participate in the development and invasiveness of adenoid cystic carcinoma by immunohistochemical study and western blot analysis.

• Korean Journal of Agricultural Science
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• v.20 no.2
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• pp.221-236
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• 1993

Economic conditions of Korean agriculture have been aggravated since farmers experienced the shortage of labor, instability of farm product price, lack of capital and pressure of opening domestic market. Nevertheless, agriculture must be maintained because structure of national economy can not be progressed without balanced growth of food industry. So the problem that we must solve is to keep agriculture competitive. In that case technology is important in terms of improving productivity, overcoming labor shortage and stabilizing price. This paper is to study the technology adoption on the farm level, focusing on the theories of technology adoption, their empirical test and effect of technology adoption on the farm household income. In this study five theories-independent model, linear model, middle class conservation model, modified middle class conservation model, basic needs and wealfare model- were introduced concerning differentiated technology adoption rate by farmers' class. Based on the survey of controlled strawberry farming in Nonsan County, Chungnam Province, who adopted six kinds of technology, modified middle class conservation model was found to explain five kinds of technology adoption pattern and linear model was useful to explain one kind of technology, that is, irrigation method, These results may mean that controlled strawbary cultivators of middle class were reluctant to accept new technology. There are many variables to effect on the technology accepting rate, that is, farmer's age, labor capacity, education level, cultivation career, size of total cultivated land, and size of strawberry farming land. LOGIT model was used to find which variable influence the technology adoption rate. Results of estimation showed that variables of cultivation career and total land size, of which coefficients were statistically significant at the 5 percent level, might be main influential factors in accepting more than three farming techniques. There was a significant income difference between farm households accepting new methods and those rejecting them. Especially in case of low class of farming group, income of farmers who was adopting new technology was examined to be much higher than that of farmers who did not adopt. This result suggests that new technology play an important role in increasing farm household income. Finally this study emphasized that there is a need to develop proper measure of technology transfer considering various socioeconomic conditions of farm households.

• Journal of Science and Technology Studies
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• v.16 no.1
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• pp.29-61
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• 2016

This paper explains the one of the most problematic factor in the society that leads to social inequality - increase in non-regular work. Theoretically, this expansion of non-regular work can be explained by technologies that are designed to save the labor force, especially since corporations in Korea have strategies to replace the regular workers with temporary workers, to save money. OECD also noted that Korea's income inequality is pretty high in ranking when compared with the rest of the OECD members, and says that globalization and technological innovation are the factors of this problem. To refine the argument, this study also looks at relationship between development made in sciences - which can be stated as a proxy variable to look at the advances made in technology - and expansion of temporary work force by using VAR methodology. Based on the results of this analysis in the future temporary/regular workers ratio started with decline, then turn to rise. These temporary/regular workers ratio sustained growth prediction shows that the expansion of the temporary expansion contributes to instability and social inequality in the labor market and technological change are interrelated.

• Journal of Korean Academy of Nursing
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• v.22 no.4
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• pp.552-568
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• 1992

Recent improvements in the standard of living, national income and medical care, and a decline in the infant death rate which have occurred related to economic growth and modernization, have led to a longer average life-span and a higher ratio of elderly people in the total population, Therefore, not only in the field of nursing science, but also in the field of many other discipline, issues concerning the elderly have been given increasing interest. A great deal of effort has been spent on increasing the quality of life for elderly people. This study was conducted to analyze the correlation between social support and quality of life. The sample consisted of III subjects residing at home and 107 subjects residing in institutions all of whom were over 65 years of age. The data collection period was from October 23, 1990 to January 26, 1991. Social support was measured using the Norbeck social Support Questionnaire developed by Norbeck, translated by Oh, Ka Sil and quality of life was measured using the QOL scale developed by No, You Ja. Data were analyzed using pereentages, t-test, Pearson Correlation Coefficient and ANOVA. The results of this study are as follows : 1. There was a statistically signifivant difference in the level of social support between the two groups (t＝-8.83, p＜.001), The elderly at home reported a much higher level of social support. 2. There was a statistically significant difference in the level of QOL between the two groups (t＝-5.77, p＜.001) . The elderly at home reported a much more positive quality of life. 3. There was a positive correlation between social support and QOL for the elderly at home ard it was statistically significant (r＝.32, p＜.001). 4. There was a postitive collealtion between social support and QOL for the elderly in institutions and it was also statistically significant (r＝.19, p＜.05). 5. The relationship between the general characteristics of the elderly at home and the variables of social support and of QOL were as follows ; 1) according to sex(t＝10.57, p＜.01) and the number of offspring(F＝6.19, p＜.01), there was a statistically significant difference in social support. 2) according to amount of Pocket money, there was a statistically significant difference in QOL(F＝2.98, p＜.05). 6. The relationship between the general characteristics of the elderly in institutions and the two variables were as follows ; 1) according to sex(t＝6.24, p＜.05), the number of offspring(F＝6.16, p＜.001) and religion (F＝2.58, p＜.05), there was a statistically significant difference in social support. 2) according to religion, there was a statistically significant difference in QOL(F＝2.90, p＜.05). In conclusion, it can be said that social support is an important variable related to QOL in the elderly and that social support levels are higher for the elderly residing at home. Therefore, more specific and objective approaches and efforts are needed to effectively use resources to maintain the elderly at home and to enhance social support available to the elderly in institutions and thereby increase QOL regardless of residence.

• KDI Journal of Economic Policy
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• v.35 no.4
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• pp.31-61
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• 2013

The purpose of this study is to calculate the economic value of transport demand forecasting risks in the road PPP project. Under the assumption that volatility of the road PPP project value occurs only in regard with uncertainty of traffic volume forecasting, this study calculates the economic value of the traffic forecasting risks in the case of the road PPP project. To that end, forecasted traffic volume is assumed to be a stochastic variable and to follow the Geometric Brownian motion as time passes. In particular, this study attempts to differentiate itself from existing studies that simply use an arbitrary assumption by presenting the application of different traffic volume growth volatility and the rates before and after the ramp-up period. Analysis of the case projects reveals that the risk premium related to traffic volume forecast of the project turns out as 7.39~8.30%, without considering option value-such as minimum revenue guarantee-while the project value volatility caused by transport demand forecasting risks is 17.11%. As the discount rate grows higher, the project value volatility tends to decrease and volatility in project value is always suggested to be larger than that in transport volume influenced by leverage effect due to fixed expenditure. The market value of transport demand forecasting risk-calculated using the project value volatility and risk premium-is analyzed to be between 0.42~0.50, implying that a 1% increase or decrease in the transport amount volatility would lead to a 0.42~0.50% increase or decrease in risk premium of the project.

• Journal of Life Science
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• v.18 no.11
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• pp.1606-1611
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• 2008

Outer membrane proteins (OMPs) expressed in the Gram negative bacteria such as Salmonella play multiple functions including material transports, adhesive factors and reception of external signals. This study has been focused on an OmpW protein known as a protein required to form a hydrophobic porin in outer membrane. We have constructed a S. typhimurium CK10 mutant deleting an ompW gene on chromosome. The CK10 strain was more tolerant to SDS than the wild-type strain did. As increase of salt concentration in the culture media, significantly decreased amount of OmpW protein in cells were detected. The maximum OmpW protein was expressed in the absence of salt supplement. However, the growth of CK10 strain was indistinguishable compared to that of the wild-type strain at the variable osmotic conditions. The biological role of differential OmpW expression in response to osmotic conditions remains to be investigated.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.1-8
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• 1993

Extruded defatted soy flour (DSF) with twin screw extruder was compared with steam treated DSF for soy sauce fermentation. Independent variables of response surface methodology (RSM) for extrusion were barrel temperature $(145{\sim}165^{\circ}C)$, feed moisture content $(25{\sim}35%)$, and feed rate $(20{\sim}30\;kg/hr)$. Extrusion conditions for production of the extrudates having highest water absorption capacity, lowest bulk density and highest expansion ratio were obtained by regression analysis of each dependent variable. Electron photomicrographs revealed significant increase of porosity inside the koji made from extruded DSF. Therefore, growth of fungi inside the koji made from extrudates of DSF was accelerated to achieve higher activities of protease, ${\alpha}-amylase$, and glucoamylase compared to the koji made from steamed DSF. Although amino acid composition of soy sauces prepared from two different DSF did not show any significant difference, the content of free amino acids in soluble nitrogen compounds was higher $(13%{\pm}2)$ in soy sauce made from extruded SDF. During the whole period of fermentation color of soy sauce made from extrudates of DSF was darker. Sensory evaluation did not reveal any serious off-odor and off-taste in the soy sauce fermented from extruded DSF.