• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.44-52
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• 2010

The objective of this in vitro study was to detect and monitor demineralization and remineralization of primary teeth according to restorative materials using quantitative light-induced fluorescence (QLF). A single bur hole was drilled on the each sound forty eight primary anterior teeth, and the specimens were divided into three groups. The cavity was restored with $Filtek^{TM}$ Z250(Group 1), F2000(Group 2), $Ketac^{TM}$ N100(Group 3) following the manufacturer's instructions. The teeth were subjected to the demineralizing buffer for 3 days, and then subjected to a remineralizing buffer for 14 days. The change of mineral loss(${\Delta}Q$) according to the stages was evaluated by QLF and the following results were obtained: 1. When demineralization was done, ${\Delta}Q$ was increased as follows. : Group 1 ($-110.79\;{\pm}\;27.77$) < Group 2 ($-104.84\;{\pm}\;28.95$) < Group 3 ($-90.16\;{\pm}\;21.87$) : Resistance to demineralization was statistically significant in Group 3. 2. There was a statistically significant increase in ${\Delta}Q$ of all groups since 1st day of remineralization 3. The rate of remineralization, ${\Delta}$(${\Delta}Q$)/day, showed significant high value in each group on the 1st day then decreased rapidly. 4. There was no statistically significant difference in the degree of remineralization among restorative materials.

• Culinary science and hospitality research
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• v.17 no.1
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• pp.26-43
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• 2011

This study aims to give insight into better understanding how service quality influences customers' attitude and behavior in terms of loyalty as well as how its effects vary by the types of restaurants (family restaurants or fast food restaurants). The results of the study are summarized as follows. First, perceived service quality, which consists of food, service, menu and atmosphere, made a significant impact on customer satisfaction for food, menu, atmosphere, and service, respectively. Second, the study examined how perceived service quality affected future expectations, and found only food turned out to be a significant factor. Third, customer satisfaction affected future satisfaction and customer loyalty, and it had a greater impact on attitudinal loyalty than behavioral loyalty. Fourth, future satisfaction affects customer loyalty, and it had a greater impact on attitudinal loyalty than behavioral loyalty. Fifth, the study examined how service quality, customer satisfaction and future expectation affected attitudinal loyalty and behavioral loyalty differently by different types of the food service industry (family restaurants or fast food restaurants) and found out there were some differences in the effects of customer satisfaction on behavioral loyalty and the future expectations and attitudinal loyalty on behavioral loyalty. The marketing implication is that service providers should be one step ahead in understanding the service quality perceived by customers (food, service, menu, and atmosphere). In addition, they should understand that establishing long-tenn relationships with customers by providing high quality service bas a direct impact on their business performance. Furthermore, management in family restaurants and fast food restaurants should include the improvement of service quality in their employee training programs.

• The Korean Journal of Financial Management
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• v.21 no.2
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• pp.125-151
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• 2004

This study tests the price discovery from US Treasury bond markets to Korean bond markets using the daily returns of Korean bond data (CD, 3-year T-note, 5-year T-note, 5-year corporate note) and US treasury bond markets (3-month T-bill, 5-year T-note 10-year T-bond) from July 1, 1998 to December 31, 2003. For further research, we divide full data into two sub-samples on the basis of the start-up of bond valuation system in Korean bond market July 1, 2000, employing uni-variate AR(1)-GARCH(1,1)-M model. The main results are as follows. First the volatility spillover effects from US Treasury bond markets (3-month T-bill, 5-year T-note, 10-year T-bond) to Korean Treasury and Corporate bond markets (CD, 3-year T-note, 5-year T-note, 5-year corporate note) are significantly found at 1% confidence level. Second, the price discovery function from US bond markets to Korean bond markets in the sub-data of the pre-bond valuation system exists much stronger and more persistent than those of the post-bond valuation system. In particular, the role of 10-year T-bond compared with 3-month T-bill and 5-year T-note is outstanding. We imply these findings result from the international capital market integration which is accelerated by the broad opening of Korean capital market after 1997 Korean currency crisis and the development of telecommunication skill. In addition, these results are meaningful for bond investors who are in charge of capital asset pricing valuation, risk management, and international portfolio management.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.295-303
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• 1997

To investigate the transformation characteristics of nitrogen and carbon from cow manure compost amended in soil under different moisture conditions, dynamics of nitrogen and carbon were determined periodically for 15 weeks of aerobic incubation at room temperature during July${\sim}$November, 1996. Cow manure compost matured with mixing saw dust was amended with the 4 ratios (0, 2, 4, 6%(wt/wt)) in Ap horizon soil, which collected from green house in Yesan, Chungnam. Moisture was controlled with 0.2, 0.3, 0.4, and 0.5 of mass water conte nt (${\theta}$m) to air dried soil, and water loss was compensated at every sampling. During incubation, soil pH was decreased continuously, that was caused by hydrogen generated from nitrification of ammonium nitrogen. And pH became higher with inclining cow manure compost amendment and water treatment, that meaned the increase of mineralization of organic-N to $NH_4\;^+-N$. Total nitrogen was reduced with increasing water content, but total carbon showed the contrast tendency with that of nitrogen. Therefore, C/N ratio slightly decreased in the low water condition (${\theta}$m 0.2) during incubation, but increased continuously in high water condition over ${\theta}$m 0.4. As a result, it was assumed that soil fertility is able to be reduced in the high water content over available water content. Nitrate transformation rate increased lasting in the low water content less than ${\theta}$m 0.3. Itdropped significantly in the first $2{\sim}3$ weeks of incubation over ${\theta}$m 0.4. In particular, nitrate was not detected in ${\theta}$m 0.5 of water content after the first $2{\sim}3$ weeks. In contrast, ammonium transformation was inclined with increasing water treatment. Nitrogen mineralization rate, which calculated with percentage ratio of (the sum of ex.$NH_4\;^+-N$ and $NO_3\;^--N$)/total nitrogen, was continuously increased in the low water content of ${\theta}$m 0.2 and 0.3. But it saw the different patterns in high water content over ${\theta}$m 0.4 that was drastically declined in the initial stage and then gradually inclined . From the above results, nitrogen transformation patterns differentiated decisively in water content between ${\theta}$m 0.3 and 0.4 in soil. Thus, it is very important for the maintain of suitable soil water content to enhance fertility of soil amended with manure compost. However, excess treatment of manure compost might enhance the possibility of contamination of small watershed and ground water around agricultural area.

• Journal of Animal Environmental Science
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• v.18 no.2
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• pp.111-122
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• 2012

Establishment of the LFQC (Liquid Fertilizer Quality Certification) system is very urgent issue for recycling livestock manure as renewable resources in Korea faced with environmental problem of manure application to land due to intensive livestock farming. In this study, we investigated relevant laws and regulations on livestock manure fertilizer, certifications of eco-friendly agricultural products, government policies on livestock manure management to establish reasonable direction of Korean LFQC (Liquid Fertilizer Quality Certification) system. As a result from this study, the liquid fertilizers in 'LFQC' system could be classified as three levels according to the usage patterns in field; 1st. Individual Farm Level (IFL), 2nd. Joint Farm Level (JFL), and 3rd. Commercial Level (CML). And finally, we found some characteristics in 'Main Level-Grading Factors' of liquid fertilizer such as fertilizing value, harmfulness, stability, uniformity, economic effect, storage potential, commercial value, functionality. Those items were considered to be the key factors for the establishment of 'LFQC' system. More research on 'Evaluation Standards' for concrete guideline and on the 'Main Level-Grading Factors' be needed to complete Korean LFQC system.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.4
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• pp.14-25
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• 2016

This study aims to investigate what flowering plant Jeongjo loved, the attitudes and the reasons, and their implications. The study method was to investigate the contents and meaning in the historical records and to describe their interpretation. Jeongjo's life was consistent with very abstinent life style. His food, clothing and shelter were simple, and he did not show the interests in music, various arts and craft, women, and so on. He did not even show his interest in the flowers and plants of fairyland, beautiful flowers and plants. Jeongjo knew various kinds of flowers, and he was proficient in artistic expressions such as literature or painting with flower material. Due to this kind of attitude, there were few cases to demonstrate his taste on the specific flowering plant. The only one that Jeongjo revealed as his favorite flower was the pomegranate. However, the pomegranate was not the simple flowering plant as the subject of enjoying to Jeongjo. The pomegranate has the meaning of indicator plant to indicate the season of rice farming. Therefore, he made it to be the intermediary to indicate the farming season, which counted a few. Besides, Jeongjo who was threatened by the trials of assassination to him in his early throne period utilized 5,600 pomegranate flowerpots as the barricade of his shelter by arraying them with the type of stone piles in $B{\bar{a}}zh{\grave{e}}nt{\acute{u}}$(八陣圖). The use of Jeongjo's pomegranate flowerpots was not related to the visual utilization like ornament at all, which was very unique case. From multiple records, it was found that the pomegranate was the flower to be with Jeongjo in his period of reign. It is remarkable that the reason why Jeongjo kept pomegranate for a long time like this had the difference from enjoying practice on the ordinary flowering plant. This study has the limitation to be conducted depending on the Korean translated data. Further studies are required according to the translation performance of new historical records.

• Korean Journal of Social Welfare Studies
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• v.49 no.2
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• pp.125-157
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• 2018

In the reality that the seriousness and concern about the youth problem is increasing, this study focuses on the vision plan project supporting the NEET youth in the social welfare field. Therefore, this study analyzed how the social workers recognized the NEET problem before participating in the project, what difficulties they experienced in the process of the project, and how they coped with these difficulties. The results of the study are as follows. Social workers were saddened by the seriousness of the youth problem before their participation, but they recognized that there was no way to solve it and many social workers were not fully aware of the youth or NEET issues. In this context, in the course of running a project with NEET youth, social workers experienced difficulties due to the nature of the NEET youth, difficulty in forming a relationship with NEET youth, and difficulties for young people not to spend time in the program. And social workers also faced difficulties due to the lack of know-how in the project, difficulties in operating the center alone, and difficulty in achieving employment goals. In the process of coping with these difficulties, social workers have actively sought, persuaded and supported the NEET youths to participate in the project, adapted the time, place and method to the youth, and removed the stigmatization element in the project. They also worked closely with local residents, local institutions and municipalities, formed networks, and changed the viewpoint of providing work experience rather than getting young people, but seeing long-term outcome. As a result, social workers have experienced not only individual change but also social welfare organization, field, community and local institutional change. Based on these results, this study suggested that the social welfare practice field should provide various activities in the process of supporting the youth gap year policy. In addition, this study suggests that the social workers play a role in connecting various actors rather than suppliers when working with young people, and that the social welfare field should expand the scope of project to include youth.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.2
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• pp.101-107
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• 2005

To investigate the effect of pyroligneous acid liquor (PAL) on the maturity of pig manure compost, PAL was treated to the compost piles. The treatments included applications of 100 and 300 times diluted PAL in addition to the control. The compost piles were stirred in three times at the 1st, 10th, and 25th day of composting. Temperature in the compost pile of control treatment increased from 28 to $60^{\circ}C$ within 10 days and remained nearly at the level until 30th day, then it began to decrease. On the other hand, temperature of the PAL-100 and PAL-300 treatments reached 65 to $70^{\circ}C$ within 8 days and became stabilized until 30th day, then the temperature decreased to about $28^{\circ}C$. However, the temperature of control was stabilized approximately at the 40th day. Initially, the pH of control treatment dropped from 8.2 to slightly above pH 8.0 during 4th day, but that of the PAL-100 treatment declined to 7.8. Among treatments, pH value of PAL-100 treatment was the lowest, which was about 7.3 after becoming stabilization. Also the germination index (GI) was increased at all treatments. The C/N ratio range of PAL-100 treatment was better balanced than others and was at 24.3. Moreover the round paper chromatogram of extracted solution of compost of PAL-100 treatment was the sharpest and clearest among treatments. The GI values of control, PAL-100, and PAL-300 in 60 days of composting were about 108, 120, and 118 in germination test using chinese cabbage, respectively. It can be concluded that the addition of diluted PAL solution is effective in composting of pig manure.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.347-352
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• 2011

Environment-friendly agriculture (EFA) are aimed to reduce use of chemical inputs as possible the recycling of resources and the environment while preserving the local resources in the long term to ensure a constant productivity and profitability for producing safe food. This study was conducted to investigate characteristics on soil environment at paddy field of environment-friendly agriculture regions (EFARs) in Honam area. Survey point of EFARs Chungnam, Jeonbuk and Jeonnam, rice bran farming method in two districts, rice bran + snail farming method in eight districts, snail farming method in five districts and ducks farming method in three districts a total of 18 districts were selected. Annual of farming method, friendly-environment certification, amount of applied fertilizer, and history of cultivation to the farm household were surveyed. The content of available phosphate and silicate among the soil chemical properties in EFA paddy field were a little lower than optimum level, and those of agricultural methods fertilized with rice bran were a little lower than those of others. Hardness among the soil physical properties in EFA paddy field were a little lower than conventional practices, and that of agricultural methods fertilized with rice bran were a little lower than those of others. We showed fertilizer recommendation dose about soil nutritional shortages according to fertilization prescriptions index by crops.

• Journal of Korean Society of Forest Science
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• v.110 no.3
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• pp.406-418
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• 2021

This study was conducted to evaluate optimal storage techniques for bare root plants and container seedlings of Quercus variabilis and Zelkova serrata in order to maintain high quality of seedlings until planting. Refrigerated storage treatments were given at two temperatures (-2℃ [freezing] and 2℃ [cooling]) for nine different durations (0, 15, 30, 60, 120, 180, 240, 300, and 360 days after storage). We analyzed total nonstructural carbohydrate (TNC) content and measured shoot moisture content (SMC) during the storage stage and survival rate (SR) and dry weight during the planting stage of seedlings. The TNC content and SMC of the seedlings of the two species decreased with an increase in storage duration. The TNC content of seedlings rapidly decreased after 180~240 days of storage. The TNC reduction rate in the freezing treatment was lower than that in the cooling treatment. Also, with an increase in the storage duration of the two species, the SMC reduction rate in the cooling treatment increased in comparison with that in the freezing treatment. In both the species, the SR after planting decreased rapidly after 60 days of cooling storage and 180 days of freezing storage, respectively. The SR after planting was less than 60% when the TNC content for both the species dropped below 20 mg g^-1. In addition, the SR was lower than 80% when SMC measured before storage decreased by approximately 30% and 20% for Q. variabilis and Z. serrata, respectively. Our results suggest that cooling (1~2℃) storage is recommended for a short-term period (2 months or less), whereas freezing (-2~-4℃) storage is suitable for longer periods (2~6 months). These optimal storage techniques, allied with seedling harvesting and handling systems, will improve the quality of seedling production in nursery stages and increase seedling growth performances in plantations.