• Korean Journal of Agricultural Science
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• v.36 no.2
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• pp.135-145
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• 2009

This research was conducted to investigate the effect of various phosphorus concentrations in fertilizer solution on growth of and nutrient uptake by 'Chugyang' egg plant (Solanum melongena L.). Tissue and soil analyses were also conducted to set the threshold levels of phosphorus in plants when disorders develop for phosphorus deficiency or excess. Brown and purple areas developed on the margin of mature leaves and it enlarged rapidly in P deficient plants. The fruits in P deficient plants were small and dull purple in color. When P were excess in fertigation solution, the margins of lower leaves became scorched and it enlarged to inner part of the leaves. The fruits of P excess plants became small and had the curl shape. The tissue $PO_4$-P contents in the most recently fully expanded leaves and dry weight of full above ground plant tissue at 35 days after transplanting showed quadratic response ($y=0.7887+0.2394x-0.0197x^2$) and cubic response ($y=10.43+14.47x-4.7642x^2+0.3977x^3$) to elevated $PO_4$-P concentrations, respectively. When 10% reduction in dry weight set to threshold levels, optimum tissue $PO_4$-P contents are between 0.98 to 1.35%. The yield determined at 150 days after transplanting also showed cubic response to elevated phosphorus concentrations in fertigation solution ($y=1194.6+1502.2x-454.5x^2+35.64x^3$). When the 10% reduction in yield is set to threshold levels, the tissue $PO_4$-P contents for maximum yield should be around 1.53% to 2.25% in most recently fully expanded leaves at 150 days after transplanting.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.521-525
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• 2001

This study investigated the effects of conventional predrying and modified atmosphere (MA) on the head quality and storability of Chinese cabbage 'Norang' cultivar. Immediately after harvest, heads were predried for 2 days and MA stored in $50{\mu}m$ PE film packages at $4^{\circ}C$. MA packaging restrained Hunter L and b values of Chinese cabbage more effectively than non-packaging during storage at $4^{\circ}C$. But there was little change between the two treatments. Fresh weight decreased less in heads treated with predrying and MA than non-treatment during storage. Predried Chinese cabbage heads kept a high level of soluble solids in 4 weeks of storage, while non-packaging maintained high contents of soluble solids for 6 weeks of storage period. Chinese cabbage heads contained 7.0 mg/gFW glucose, 6.3 mg/gFW fructose, and 0.6 mg/gFW sucrose as major soluble sugars at harvest. The content of sugars decreased immediately after predrying and increased steadily after 2 weeks storage. It was found inappropriate to assess head quality of Chinese cabbage by investigating was investigated by Hunter a, firmness, dry matters content, pH, and soluble sugars after predrying and MA package. Marketability of Chinese cabbage was lost when heads were stored at room temperature in 2 weeks. It showed poor appearance of heads stored at $4^{\circ}C$ in 7 weeks. Decay occurred in Chinese cabbage stored in MA under excessive relative humidity. Predried head showed good appearance during storage at $4^{\circ}C$ for 7 weeks. As a result, Chinese cabbage heads can be successfully stored for at least 7 weeks with predrying and MA storage.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.2
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• pp.179-190
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• 2010

The experiment was conducted to observe the effects of dried whole crop barley treated with cellulolytic microorganisms (Aspergillus niger KCCM 60357 and Bacillus licheniformis KCCM 40934) on the chemical composition, in vitro colonic fermentation and whole tract digestibility in swine. Whole crop barley were fermented with no microorganism addition (control), A. niger, B. licheniformis and co-culture of A. niger and B. licheniformis (Mixture) for 3 days at $30^{\circ}C$. In the feed chemical composition, CP contents of whole crop barley treated with A. niger (7.52%) and B. licheniformis (7.77%) were significantly higher than control (6.81%) (p<0.05). The in vitro colonic fermentation of dried whole crop barley fermented with control showed significantly higher $CH_4$ contents than A. niger, B. licheniformis and Mixture at 18h incubation (p<0.05). Dry matter (DM) digestibilities of A. niger (55%) and Mixture (57.42%) treatments were significantly higher than control (43.74%) (p<0.05). Ammonia-N was significantly increased in A. niger, B. licheniformis and Mixture relative to control at 24 hour incubation (p<0.05). Xylanase activities in A. niger, B. licheniformis and Mixture treatments were significantly higher than control at 24 hour incubation (p<0.05). Concentrations of total VFA were significantly increased in B. licheniformis (12.61 mM) at 24hour incubation (p<0.05). In vitro whole tract digestibility was significantly increased in B. licheniformis (49.61%) compared with the control (45.65%) (p<0.05). In conclusion, whole crop barley treated with cellulolytic microorganisms improved whole tract digestibility and colonic fermentation for swine.

• Korean Journal of Poultry Science
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• v.36 no.4
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• pp.279-286
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• 2009

An experiment was conducted to investigate the effects of dietary supplementation of cerium (Ce), a rare earth, individually and in combination with lanthanium (La), a rare earth, in the basal diet on growth performance, nutrient digestibility, bone composition, breast meat composition, carcass characteristics and meat color in broiler chicks. A total of 1,600 day-old broiler chicks were randomly allotted to four dietary treatments with four replicates in a completely randomized block design. Treatments were T1) CON (control diet), T2) 100 ppm Ce, T3) 100 ppm La, T4) 100 ppm Ce+100 ppm La. There were no significant differences in feed intake among dietary treatments during the whole experimental period (0 to 5 weeks). Body weight gain for the first three weeks was greater in birds T4 than birds fed T3 diet. Feed conversion ratio (FCR) was better in birds fed T4 diet (p<0.05) than birds fed T3 diet during 0~3 weeks, and better FCR for 0~5 weeks was noticed in birds fed T4 diet than birds fed T1 diet. Nutrient digestibility was greatest in birds fed T3 diet (p<0.05) compared with other treatments. Bone composition, carcass characteristics and meat color were no statistically different among the treatments. These results suggest that Ce supplementation, alone and combination with La could improve performance of broilers.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.530-534
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• 2006

조류발전은 조류 유속이 빠른 곳에 수차발전기를 설치하여 해수의 운동에너지로부터 전기를 생산하는 발전방식이다. 2001년부터 해양연구원에서는 울돌목의 우수한 조류발전 개발 여건을 바탕으로 조류에너지 실용화 기술을 개발하고 있다. 본 연구에서는 조류발전 시스템에 사용되는 헬리컬 수차의 효율을 현장실험을 바탕으로 판단하고자 하였다. 현장실험을 위하여 지름 2.2 m, 높이 2.5 m의 수차를 제작하고, 울돌목 협수로의 한 쪽 면에 쟈켓구조물을 설치하여 수차를 거치한다. 수차가 회전함에 따라 회전봉에 일정 마찰을 주어 토크와 RPM을 측정하고, 함께 측정된 유속자료를 이용하여 수차를 효율을 산정한다. 유속-수차효율, TSR(수차의 날개속도와 유속의 비)-수차효율의 상관관계로 실험결과를 고찰하였다. 1중 날개 수차인 경우에 유속 1.4에서 2.6 m/s 사이에서 최대효율이 30 - 35 % 정도였고, 2중 날개 수차에 대한 실험에서는 유속 1.4에서 2.6 m/s 사이에서 최대수차효율이 25 - 35 % 사이임을 알 수 있었다. TSR과 최대수차효율의 상관관계는 실험 case별로 조금씩 다르다. 전체적으로 1중 날개의 경우가 최대수차효율에서 2중 날개보다 TSR 값이 조금 큰 경향을 나타냄을 알 수 있다. 이것은 1중 날개가 2중 날개보다 가벼워 좀 더 큰 RPM을 발생시켜서 나타난 현상으로 생각된다. 현재의 실험결과들을 이용하여 TSR과 최대수차효율을 상관관계를 나타내는 모델식을 도출하였다. 현장시험결과를 종합하면, 현장조류발전 시설이 최소 600 kW의 전력이 생산되기 위해서는 지름 3 m, 높이 3.6 m 인 수차 3개가 하나의 축에 설치되어야하는 것으로 계산되었다. 정격유속이 4.8 m/s이고 수차의 지름이 3m 라면, 최적 전력발생시의 RPM은 1중 날개의 경우 79이고 2중 날개의 경우는 63정도임을 추정할 수 있었다.촬영하여 실시간으로 전송하기 때문에 홍수시 하천 상황에 대한 모니터링 목적으로 사용될 수 있다. 영상수위계는 우물통 등을 이용하는 기존 방법과 비교하여 구조물이 필요 없어 설치 비용이 저렴하고, 영상에 의한 하천 모니터링 기능을 자체적으로 가지고 있기 때문에 효율적이라고 할 수 있다.따른 4개의 평가기준과 26개의 평가속성으로 이루어진 2단계 기술가치평가 모형을 구축하였으며 2개의 개별기술에 대한 시범적용을 실행하였다.하는 것으로 추정되었다.면으로의 월류량을 산정하고 유입된 지표유량에 대해서 배수시스템에서의 흐름해석을 수행하였다. 그리고, 침수해석을 위해서는 2차원 침수해석을 위한 DEM기반 침수해석모형을 개발하였고, 건물의 영향을 고려할 수 있도록 구성하였다. 본 연구결과 지표류 유출 해석의 물리적 특성을 잘 반영하며, 도시지역의 복잡한 배수시스템 해석모형과 지표범람 모형을 통합한 모형 개발로 인해 더욱 정교한 도시지역에서의 홍수 범람 해석을 실시할 수 있을 것으로 판단된다. 본 모형의 개발로 침수상황의 시간별 진행과정을 분석함으로써 도시홍수에 대한 침수위험 지점 파악 및 주민대피지도 구축 등에 활용될 수 있을 것으로 판단된다. 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전략은 존재하므로 이러한 전략을 개발 및 활용할 수 있으며, 특히, 한국주식시장에 적합한 거래전략은 반전거래전

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.3
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• pp.163-175
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• 1974

Effects on yields, yield components and nutrient content of potassium depression for two or three weeks at various growth stages were investigated in rice (var. Jinheung) under sand culture system.(K 40 ppm 1973) 1. Analysis of variance showed significant difference among treatments of both two-week (at p=0.01) and three-week depression (at p=0.05) in yield. 2. Most sensitive stage to potassium depression on yield appeared two weeks until heading (42% yield decrease) and sensitivity decreased the growth stage is apart from heading either before or after. During 30 days after transplanting two-week potassium depression increased yield, but three-week depression decreased yield. Until about 30 days after heading depression caused poor yield. 3. Root potassium involves in harvest index, filled grain ratio and grain weight with significant correlation and considerably in spikelet per panicle while potassium in leaf sheath+culm involves considerably in spikelet per panicle and panicle per hill. Relative total dry matter weight was significantly correlated with panicle per hill, spikelet per panicle and K or K/Ca+Mg only in leaf sheath+culm. The indications are that root potassium contributes for building sink and efficiency of structure while potassium in leaf sheat+culm primarily for building source, productive structure. 4. Relative yield was significantly correlated with potassium content in root and leaf sheath+culm and with K/Ca+Mg and its ratio before and after depression in root indicating that potassium depression occurs greatly in root and that K/Ca+Mg might have more important role than K content alone under depression. 5. Optimum level of $K_2O$ appears around 3% in leaf blade. 4% in leaf sheath+culm and 1% in root under the assumption that below these level the same content has the same role in relation to yield during growth. The K/Ca+Mg appeares to be 2.5 in root and should not decrease throughout the growth stages. 6. The increase of sodium content in plant by K depression was highest, especially in leaf sheath during the most insensitive period to K depression suggesting that insensitivity may be attributed to partial replacement of Na for K. Partial replacement seems very little in sensitive stage (later stage) and sensitive organ (root).

• Journal of Animal Environmental Science
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• v.13 no.1
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• pp.21-28
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• 2007

This experiment was conducted to determine the effect of feed intake and water consumption on milk yield and manure production in milking cows. The average feed intake(dry matter) of milking cows were 19.5kg/hd/d. Spring(23.9kg) and fall(22.1kg) feed intake rates when higher than in the summer(17.0kg) and winter(15.3kg/hd/d). The average water consumption of milking cows were $77.2\ell/hd/d$. Summer showed the highest value$(85.5\ell/hd/d)$ and winter showed the lowest value$(62.2\ell/hd/d)$. The average milk yield during spring, summer, fall, and winter was 30.8, 24.0, 25.4, and 23.7kg/hd/d, respectively. Milk yield during spring was found to be statiscally greater than for the other seasons. Manure production of milking cows during spring, summer, fall, and winter was 64.4, 63.5, 60.4, and 51.0kg/hd/d, respectively. Consequently, a relatively high correlation between milk yield and water consumption$(R^2=0.7742)$, milk yield and feed intake$(R^2=0.7459)$, water, consumption and urine production$(R^2=0.7422)$, feed intake and feces production$(R^2=0.6044)$, and milk yield and feces production$(R^2=0.6920)$ were observed in milking cows. The other hand, correlation between water consumption and feces production$(R^2=0.2950)$, feed intake and urine production $(R^2=0.1985)$, and milk yield and urine production$(R^2=0.2335)$ were found to be relatively low. Therefore, correlation equation between milk yield and feed intake, milk yield and water consumption can be estimated from : $Y=0.1919X_1+11.181(R^2=0.7742),\;Y=0.8568X_2+9.3067(R^2=0.7459)$(Y=milk yield $X_1=water$ consumption, $X_2=feed$ intake).

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.89-94
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• 2005

This study was conducted to investigate the effect of nonwoven fabrics weight(Ounce) on growth, quality and yield of oriental melon (Cucumis melo L. var. makwa Mak.). Seedling of 'Gumssaragi-Eunchun' was grafted on 'Shinthozoa' root stock. In this study, The minimum air temperature in 6 ounce at night was $4.8^{\circ}C,\;6.9^{\circ}C$ in 9 ounce, $7.9^{\circ}C$ in 12 ounce and $8.0^{\circ}C$ in 15 ounce, respectively. Leaf length, stem diameter, leaf numbers, leaf area, fresh weight and dry weight for 30 days after planting were better in high minimum air temperature at night than in low minimum air temperature, particularly leaf areas of the plant in 9 ounce was $370cm^2$ at 30 days after planting, $116\%$ in 12 ounce, $129\%$ in 15 ounce. The xylem exudates amount in 9 ounce for 24 hours just after basal stem abscission was 10.1mg. It was 1.2 times much in 12 ounce and 1.9times much in 15 ounce than in 9 ounce at 30 days after planting. The blooming of female was faster by 6 days in 15 and 12 ounce but was delayed by 3 days in 6 ounce than 9 ounce, and the days of blooming to harvesting were shorter by 3 days in 15 ounce and 4 days in 12 ounce but was delayed by 3 days in 6 ounce than in 9 ounce. Fruit weight, fruit length, fruit diameter, flesh thickness, soluble solids, and total yield was the highest in 15 ounce followed by 12 ounce,9 ounce and 6 ounce. Fermented fruit rate was the highest in 6 ounce followed by 9 ounce, 12 ounce and 15 ounce, and marketable fruit rates were 15, 12, 9 and 6 ounce in order. Compared to 1,781kg yield per 10a of 9 ounce, $19\%\;and\;49\%$ was increased under 12 ounce and 15 ounce but $47\%$ were decreased 6 ounce.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.2
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• pp.115-123
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• 2016

In this study, the effect of energy and protein ratio on the nutrient availability and body weight gain was determined to find the proper nutrient level for the stage of replacement dairy heifers before fertilization at approximately 12~24 months old after birth. Dry matter intake showed that the TDN/CP rate of T1 (5.0:1), T2 (4.5:1) and T3 (4.0:1) resulted in similar values. Among feces, the ash content of T1 was 11.07%, which was significantly (p < 0.05) higher than that of T3 (9.69%). It was also significantly (p < 0.05) higher than that of T2 (10.32%). When the TDN/CP rate was increased, the ash content in the feces was also increased. Regardless of the initial weight, weight gain was increased significantly as the CP rate in the feed was increased on the $30^{th}$ day. On the $60^{th}$ day, T2 showed the highest rate of gain (p < 0.05). As the TDN rate was decreased or the protein rate was increased, weight gain was significantly (p < 0.05) increased. Regarding GPT level in the blood after finishing the test, T1 and T3 (112.6, 88.3 u/l) showed significantly (p < 0.05) higher value than T2 (50.9 u/l). For phosphorus level, T1 (46.3 mg/dl) showed significantly (p < 0.05) higher value than other treatments. For HDL cholesterol level, T2 (145.2 mg/dl) had significantly (p < 0.05) higher level than T1 (121.0 mg/dl) or T3 (132.3 mg/dl). For triglyceride levels, T3 (40.6 mg/dl) had significantly (p < 0.05) higher value than T1 (20.7 mg/dl) and T2 (29.0 mg/dl). For other blood parameters including BUN concentration, there were no significant (p > 0.05) difference among treatments. As a result, although feed intake and weight gain with TDN/CP rate of 4:1 showed best results, considering the excess body fat accumulation possibilities or blood metabolism, it seems 4.5:1 ratio is most appropriate.

• Journal for History of Mathematics
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• v.22 no.2
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• pp.27-52
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• 2009

This article discusses the contributions of the leader Oswald Veblen, who was the president of AMS during 1923-1924. In 2006, Korea ranked 12th in SCIE publications in mathematics, more than doubling its publications in less than 10 years, a successful model for a country with relatively short history of modern mathematical research. Now there are 192 four-year universities in Korea. Some 42 of these universities have Ph.D. granting graduate programs in mathematics and/or mathematical education in Korea. Rapid growth is observed over a broad spectrum including a phenomenal performance surge in International Mathematical Olympiad. Western mathematics was first introduced in Korea in the 17th century, but real significant mathematical contributions by Korean mathematicians in modern mathematics were not much known yet to the world. Surprisingly there is no Korean mathematician who could be found in MaC Tutor History Birthplace Map. We are at the time, to have a clear vision and leadership for the 21st century. Even with the above achievement, Korean mathematical community has had obstacles in funding. Many people thinks that mathematical research can be done without funding rather unlike other science subjects, even though they agree fundamental mathematical research is very important. We found that the experience of early American mathematical community can help us to give a vision and role model for Korean mathematical community. When we read the AMS Notice article 'The Vision, Insight, and Influence of Oswald Veblen' by Steve Batterson, it answers many of our questions on the development of American mathematics in early 20th century. We would like to share the story and analyze its meaning for the development of Korean Mathematics of 21st century.