• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.4
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• pp.254-258
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• 1998

Distribution and occurrence of weedy rice in Kyonggi region were surveyed in 1996. Weedy rice was observed in 1368 fields (54.9%) of total 2490 fields. Almost two thirds of paddy fields in northern mountainous region were contaminated by weedy rice and more severe contamination, three forths of paddy fields, was observed in suburban regions. In those regions, occurrence of weedy rice was greater than those in north-eastern inland and south-western plain regions. The occurrence of weedy rice was higher in water seeding cultivation (66.7%) than other cultivation methods. The number of weedy rice per 10a was 756.7 plants in direct seeding on dry paddy and 379.4 plants in water seeding. The occurrence of weedy rice was higher in fields planted by farmer's seeds than that of paddy fields cultivated by certified seeds, and the longer the farmer's seeds being used, the more weedy rice occurred in paddy field.

• Korean Journal of Plant Resources
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• v.20 no.3
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• pp.251-254
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• 2007

This study was conducted to investigate the optimal plant growth regulator level for the shoot formation of Lycium chinense Mill. In vitro plant propagation was developed for leaf explants of boxthorn. Leaf explants were cultured on MS medium supplemented with cytokinins (BA and 2-iP) alone. Plants were successfully regenerated through in vitro culture by using leaf explants of boxthorn grown in the field. After 4 weeks of culture, 58% of shoot formation had developed from the leaf explants. The shoot formation rate of 'Jangmyeong' was highest followed by 'Myeongan', ;Cheondae', and 'Bullo'. The use of 0.2mg/L BA was critical for enhanced production of shoot formation and resulted in 58% of the culture producing shoot formations. Regenerated plantlets transplanted to pots were developed and successfully acclimatized to greenhouse.

• Proceedings of the KWS Conference
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• v.43
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• pp.254-256
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• 2004

The purpose of this study is to establish the control method of angular distortion at the weldment of the pressure hull penetration. In order to do it, comprehensive experiment and FEA were performed to evaluate the distortion behavior for the weldment of HY-100. Based on the results, a proper deposit sequence for the both sides X groove penetration weldment was established. In addition, a proper welding sequence was proposed by evaluation of bending restraint intensity with size and position of pressure hull penetration.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2006.05a
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• pp.254-258
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• 2006

• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.253-254
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• 2004

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.254-258
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• 2001

This paper proposes a new induction heating system composed of a hyristor PWM rectifier with a resonant commutation circuit. The operation of proposed system as first analyzed by a theoretical approach with equivalent circuits. And its verification was performed by computer simulations with EMTP. The proposed system can provide a solution for the power factor problem of the existing high-power induction heating system. which uses the line-commutated thyristor bridge in rectifier side.

• Journal of Mushroom
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• v.18 no.3
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• pp.254-259
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• 2020

Grifola frondosa is a promising new kind of cultivated mushroom owing to its excellent taste and functionality. However, more research is required to determine its value. In this study, the effects of pretreating Grifola frondosa tea by drying, steaming, and warming, on quality characteristics and antioxidant activities were analyzed. There was no difference in sugar, soluble solid, and nitrogen content between dried and steamed tea. The color of the warm pretreated tea was the darkest, and the amino acid content was 462.9 mg/L, which was 1.8 times higher than that of the other pretreatments. Moreover, the warm pretreated tea had the highest total polyphenol and flavonoid content, 14.6 mg/g and 2.2 mg/g, respectively. DPPH and ABTS radical scavenging activities significantly increased with the increase of phenolic compounds. Warming pre-treatment slightly increased the taste preference to 7.0. In conclusion, warming Grifola frondosa before drying was confirmed to improve the extraction of nutrients, antioxidants, and taste preference.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.861-866
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• 2013

The aim of this study was to investigate the biodegradation of dissolved organic matter derived from animal carcass disposal soil using soil inhabited bacteria and to identify the bacteria involved in the biodegradation. The two soils were obtained from the animal carcass burial sites located in Anseong, Gyeonggi-do, Korea. The results indicated that during the biodegradation experiments (56 days), 48% of dissolved organic carbon (DOC) was mineralized within 13 days in soil-derived solution 1 (initial DOC = 19.88 mgC/L), and the DOC concentration at 56 days was $8.8{\pm}0.4$ mg C/L, indicating 56% mineralization of DOC. In soil-derived solution 2 (initial DOC = 19.80 mgC/L), DOC was mineralized drastically within 13 days, and the DOC concentration was decreased to $6.0{\pm}0.4$ mg C/L at 56 days (76% mineralization of DOC). Unlike DOC value, the specific UV absorbance ($SUVA_{254}$) value, an indicator of proportion of aromatic structures in total organic carbon, tended to increase until 21 days and then decreased thereafter. The $SUVA_{254}$ values in soil-derived solutions 1 and 2 were the highest at 21 days. The microbial analysis demonstrated that Pseudomonas fluorescens, Achromobacter xylosoxidans, Nocardioides simplex, Pseudomonas mandelii, Bosea sp. were detected at 14 days of incubation, whereas Pseudomonas veronii appeared as a dominant species at 56 days.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1439-1446
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• 2014

The purposes of this study were to analyze recognition and preference of native local foods in elementary school students in Gyeongsang-do and Jeolla-do, as well as compare regional differences in recognition and preference of native local foods between students in Gyeongsang-do and Jeolla-do. A survey was conducted on 300 elementary school students located in Gyeongsang-do and Jeolla-do. The results of this study were as follows. First, there was no significant difference in terms of recognition score of overall native local food between students in Gyeongsang (9.43 out of 20 dishes for 254 students) and students in Jeolla (9.13 out of 20 dishes for 261 students). The recognition levels (4.88 out of 10 dishes) of native local foods in students in Gyeongsang-do were significantly higher than those (4.40 out of 10 dishes) in Jeolla-do (P<0.001). Second, the preference level (2.91 points) for native local food in students in Gyeongsang-do was significantly higher than that (2.72 points) in students Jeolla-do (P<0.001) based on a 5-point Likert scale. The preference level (3.03 points) of students in Gyeongsang-do for native local food was significantly higher than that (2.80 points) of students in Jeolla-do (P<0.001) based on a 5-point Likert scale. In conclusion, students in Jeolla-do perceived native local foods in Jeolla-do and Gyeongsang-do impartially, whereas students in Gyeongsang-do perceived native local foods better. The overall sample of elementary school students preferred native local food in Gyeongsang-do to native local food in Jeolla-do. Thus, there were regional differences in terms of recognition and preference of native local foods in elementary school students. To enhance the recognition and preference of native local foods in Jeolla-do, food culture and dietary education should be carried out.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.4
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• pp.254-257
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• 2012

Hedge funds can be established in Korea after the deregulation about setting up private equity funds on September, 2011. Although the variety of asset allocation strategies is the strength of hedge funds, most of Korean hedge funds uses only the equity long/short strategy. Therefore, it is need to introduce other strategies into Korea hedge funds, however all strategies can not be adopted at once because of the infrastructure of Korea financial market. In this paper, we find the optimal introductive order of strategies for Korea hedge fund in view of individual or institutional investors. For this analysis, HFRI data are used for the historical return of each hedge fund strategy and three methods (network visualization, principle component analysis and efficient frontier optimization) are used for finding the optimal order.