• Title/Summary/Keyword: Ryu-Hee

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Analysis of Intercepted Discharge Considering the Change of Street Inlet Size (빗물받이 유입구 크기 변화에 따른 차집유량 분석)

  • Kim, Jung Soo;Ryu, Teak Hee;Rim, Chang Soo;Yoon, Sei Eui
    • Proceedings of the Korea Water Resources Association Conference
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    • 2015.05a
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    • pp.375-375
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    • 2015
  • 최근 도시화에 따른 도로구역의 증가는 도심지의 불투수면적의 확대 및 도로의 수로화를 야기하여 집중호우 발생 시 노면 및 저지대의 침수를 가중시키고 있으며, 이로 인한 인명피해 및 재산 피해는 점차 증가하는 추세이다. 이에 기후변화에 따른 강우량의 변화 및 국지성 집중호우 등을 고려하고 도심지 침수 방지 및 방재성능 강화를 위하여 과거에 간선 10년, 지선 5년에서 간선 30년, 지선 10년으로 관거의 설계빈도가 상향조정 되었다. 도심지의 도로 및 유역 유출량의 배수에 상당한 영향을 미치는 빗물받이 및 빗물받이 유입구는 도심지의 방재성능강화 목적에 맞는 설계가 이루어져야 하나 현재 국내의 빗물받이 설치기준은 하수도시설기준(2009, 환경부)에서 '빗물받이 크기별, 도로 차선별 적정 빗물받이 설치간격' 으로 설계빈도 5년을 반영하여 제시된 설치기준이므로 이에 대한 수정 및 개정이 필요한 실정이다. 이에 본 연구에서는 관거시설의 설계빈도 상향을 고려한 도로 빗물받이의 유입량 산정을 위해 빗물받이 유입구 크기별 유입량을 도로의 차선, 종경사, 측구 횡경사 및 설계빈도의 변화를 고려하여 도로에서의 유출량을 산정하였으며, Froude 상사법칙을 이용하여 수리실험모형을 제작하여 실험을 실시하였다. 빗물받이 제원은 현재 대부분의 국도에 설치되는 크기인 $40{\times}50cm$, $40{\times}100cm$$40{\times}150cm$를 축소 제작하였다. 측구의 유량은 도로의 차선(2~4차선), 경사(도로 종경사 2~10%, 측구 횡경사 2~10%) 및 설계빈도(최대 30년)을 고려하였다. 실험 결과 측구의 횡경사가 커질수록 빗물받이로 유입되는 유량은 증가하였으며, 빗물받이 유입부의 길이가 증가함에 따라 유입부 측면부를 통한 횡유입량을 증가시켜 빗물받이 유입부의 차집율을 증가시켰다. 또한, 도로의 조건 변화 및 유입량의 변화에 따라서 흐름폭이 감소할수록 차집율이 증가하였다. 수리실험결과를 토대로 도로의 조건변화(차선, 도로 종경사, 측구 횡경사) 및 설계빈도 변화를 고려한 빗물받이의 차집율을 제시하였고 이를 회귀분석 하여 빗물받이 유입구 크기별 유입량 산정식을 도출하였다. 이는 설계빈도 상향에 따른 국내 빗물받이 유입부의 설계 기준 제시에 기초자료로 활용이 가능할 것으로 판단된다.

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Screening of Antagonistic Bacteria Having Antifungal Activity against Brown Spot and Sheath Rot of Rice (벼 깨씨무늬병 및 잎집썩음병에 항진균 활성을 갖는 길항 미생물의 탐색)

  • Ryu, Myeong Seon;Yang, Hee-Jong;Jeong, Su-Ji;Seo, Ji-Won;Jeong, Do-Youn
    • The Korean Journal of Mycology
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    • v.47 no.3
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    • pp.259-269
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    • 2019
  • Brown spot and sheath rot of rice are caused by fungal pathogens such as Curvularia lunata, Cochliobolus miyabeanus, and Sarocladium oryzae, and cause losses such as reduced rice yield and quality, which is an enormous problem with serious long-term effects. To search biological control agents of phytopathogenic fungi, five kinds of useful Bacillus-like isolates which are excellent in extracellular enzyme activity and produce siderophore were selected from paddy soil of Sunchang in Korea. The selected isolates were tested for excellent antifungal activity against three of the phytopathogenic fungi that frequently occur in rice, and JSRB 177 strain had the most excellent antifungal activity. Based on the experimental results, JSRB 177 is finally selected as a candidate for biological control and identified to Bacillus subtilis through 16S rRNA sequence analysis. In addition, physiological characteristics of JSRB 177 confirmed by analysis of carbohydrate fermentation patterns and enzyme production ability. Based on the above results, JSRB 177 is expected to be used as a biological control agent for the rice pathogenic fungi. In the future, further studies related to industrialization such as port test and establishment of mass production process are needed.

The Development of the Lens of the Optical System for High Concentration Solar PV System (고집광 태양광 발전을 위한 광학시스템 렌즈 개발)

  • Ryu, Kwang-Sun;Cha, Won-Ho;Shin, Goo-Hwan;Cho, Hee-Keun;Kim, Young-Sik;Kang, Seong-Won;Kang, Gi-Hwan
    • Journal of the Korean Solar Energy Society
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    • v.31 no.2
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    • pp.82-88
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    • 2011
  • The artificial increase in the solar intensity incident on solar cells using lenses or mirrors can allow solar cells to generate equivalent power with a lower cost. There are two types of concentration optics for solar energy conversion. One is to use mirrors, and the other is to use Fresnel lenses. The gains that can be achieved with a Fresnel lens or a parabolic mirror are compared. The result showed the gains are comparable and the two configurations were developed competitively. In application areas of Fresnel lenses as solar concentrators, several variations of design were devised and tested. Some PV systems still use commercially available flat Fresnel lenses as concentrators. A convex linear Fresnel lens to improve the concentration ratio and the efficiency is devised and flat linear Fresnel lens in thermal energy collection is utilized. In this study, we designed and optimized flat Fresnel lens and the 'light pipe' to develop 500X concentrated solar PV system. In the process, we compare the transmission efficiencies according to groove types. We performed rigorous ray tracing simulation of the flat Fresnel lenses. The computer aided simulation showed the 'grooves in case' has the better efficiency than that of 'grooves out case'. Based on the ray-trace results we designed and manufactured sample Fresnel lenses. The optical performance were measured and compared with ray-trace results. Finally, the optical efficiency was measured to be above 75%. All the design and manufacturing were performed based on that InGaP/InGaAs/Ge triple junction solar cell is used to convert the photon energy to electrical power. Field test will be made and analyzed in the near future.

Preparation and Characterization of Nylon 6,5 Copolymers from ε-Caprolactam and 2-Piperidone (ε-Caprolactam과 2-Piperidone으로부터 나일론 6,5 공중합체 제조 및 특성평가)

  • Kim, Hye Young;Goh, Jin-Seon;Ryu, Mi Hee;Kim, Dae Su;Song, Bong-Keun;Lee, Seung Hwan;Park, Si-Jae;Jegal, Jonggeon
    • Polymer(Korea)
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    • v.38 no.1
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    • pp.31-37
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    • 2014
  • To prepare biomass based nylon 6,5 copolymers, ${\varepsilon}$-caprolactam and 2-piperidone, the monomers of nylon 6,5 copolymers, were synthesized respectively from lysine and 5-aminovaleric acid which were produced from glucose by the fermentation process. The copolymers were then polymerized by the anionic ring opening polymerization of them at $40^{\circ}C$, using potassium tert-butoxide as a catalyst and acetyl-2-caprolactam and carbon dioxide as initiators. The prepared copolymers were characterized with various analytical methods: their viscosity molecular weight ($M_{\eta}$) was as high as 30000 g/mol and polymerization yield was over 50%, and it was found that they were semi-crystalline polymers having melting point at $165^{\circ}C$ which was much lower than its thermal degradation point, $250^{\circ}C$. These polymers were expected to have good thermal processability and application fields.

Influence of Diagnostic Fertilization and Subsoil Breaking on Soil physico-chemical Properties in Direct Seeding of Rice on Flooded Paddy Surface (벼 담수표면 직파재배시 진단시비와 심토파쇄가 토양이화학성 및 벼 생육에 미치는 영향)

  • Yoo, Chul-Hyun;Ryu, Jin-Hee;Yang, Chang-Hyu;Kim, Taek-Kyum;Kang, Seung-Weon;Kim, Jae-Duk;Jung, Kwang-Yong
    • Korean Journal of Soil Science and Fertilizer
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    • v.39 no.6
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    • pp.334-338
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    • 2006
  • This study was conducted to evaluate the effect of improvement of soil physical properties such as deep plowing, subsoil breaking and diagnostic fertilization on the yield of rice and nitrogen-use efficiency in direct seeding on flooded paddy surface of rice. The effects of deep plowing, subsoil breaking and diagnostic application of N, P, K fertilizers, Latex coated urea(LCU), compost, silicate were investigated. The soil physical properties, such as bulk density, hardness and porosity were improved and the content of organic matter and available $SiO_2$ were also increased by deep plowing and subsoil breaking. The amount of $NH_4-N$ in soil was highly increased by diagnostic fertilization and deep plowing at 5th leaf stage. The nitrogen-use efficiency was the highest at the diagnostic application of LCU 70% applied as basal dressing with subsoil breaking. The yield of rice increased by 8% under the diagnostic application of LCU 70% applied as basal dressing with subsoil breaking compared with the conventional application.

The Effect of Popped Rice Hulls Compost Application on Soil Chemical and Physical Properties in Fluvio-marine plain paddy soils (퇴화염토지 논에서 팽화왕겨 퇴비시용이 토양이화학성에 미치는 영향)

  • Yoo, Chul-Hyun;Yang, Chang-Hyu;Kim, Taek-Kyum;Ryu, Jin-Hee;Kim, Byung-Su;Kim, Jae-Duk;Jung, Kwang-Yong
    • Korean Journal of Soil Science and Fertilizer
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    • v.39 no.6
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    • pp.403-408
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    • 2006
  • Fluvio-marine paddy soils in Korea consist of high silt content and have the hardpan located below 20~30 cm from surface soil. This properties cause poor rice rhizosphere conditions such as low permeability and porosity, high bulk density and hardness. The aims of this study was to investigate the effect of popped rice hulls compost(PRHC) on soil fertility changes in the Fluvio-marine plain paddy soils. Total nitrogen content and nitrogen mineralization rate of PRHC were 1.17 and 33.5, respectively, and its C/N ratio was 35.4. Application of PRHC increased the content of organic matter and exchangeable potassium and improved the bulk density and porosity. The content of $NH_4-N$ in soil was high in the PRHC plot until maximum tillering stage. An uptake amount of fertilized nitrogen was greater in standard fertilization plot at early growth stage, however, it was greater more in PRHC plots at the ripening period than in standard fertilization plot. Among the PRHC treated plots, uptake amount was the greatest in 50% PRHC plot during the all growth period. Nitrogen efficiencies were higher in PRHC plot during the all growth period. Rice yields in all PRHC plots were lower than in standard fertilization, however, the yield of 40% PRHC plot was similar with that of standard.

Effect of Subsurface Drainage Systems on Soil Salinity at Saemangeum Reclaimed Tidal Land

  • Lee, Sanghun;Bae, Hui-Su;Lee, Soo-Hwan;Oh, Yang-Yeol;Ryu, Jin-Hee;Ko, Jong-Cheol;Hong, Ha-Chul;Kim, Yong-Doo;Kim, Sun-Lim
    • Korean Journal of Soil Science and Fertilizer
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    • v.48 no.6
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    • pp.618-627
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    • 2015
  • Soil salinity is the most critical factor for crop production at reclaimed tidal saline soil. Subsurface drainage system is recognized as a powerful tool for the process of desalinization in saline soil. The objective of this study was to investigate the effects of subsurface drainage systems on soil salinity and corn development at Saemangeum reclaimed tidal saline soil. The field experiments were carried out between 2012 and 2014 at Saemangeum reclaimed tidal land, Buan, Korea. Subsurface drainage was installed with four treatments: 1) drain spacing of 5 m, 2) drain spacing 10 m, 3) double layer with drain spacing 5 m and 10 m, and 4) the control without any treatment. The levels of water table showed shorter periods above 60 cm levels with the deeper installation of subsurface drainage system. Water soluble cations were significantly greater than exchangeable forms and soluble Na contents, especially in surface layer, were greatly reduced with the installation of subsurface drainage system. Subsurface drainage system improved biomass yield of corn and withering rate. Thus, the biomass yield of corn was improved and the shoot growth was more affected by salinity than was the root growth. The efficiency of double layer was not significant compared with the drain spacing of 5 m. The economic return to growers at reclaimed tidal saline soil was the greatest by the subsurface drainage system with 5 m drain spacing. Our results demonstrated that the installation of subsurface drainage system with drain space of 5 m spacing would be a best management practice to control soil salinity and corn development at Saemangeum reclaimed tidal saline soil.

Effects of Rice Straw Incorporation by Cutting Methods on Soil Properties and Rice Yield in a Paddy Field (볏짚 혼입이 논 토양개선 및 쌀수량에 미치는 영향)

  • Yang, Chang-Hyu;Kim, Taek-Kyum;Ryu, Jin-Hee;Lee, Sang-Bog;Kim, Sun;Baek, Nam-Hyun;Choi, Weon-Young;Chung, Doug-Young;Kim, Si-Ju
    • Korean Journal of Soil Science and Fertilizer
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    • v.43 no.6
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    • pp.1047-1050
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    • 2010
  • This study was to investigate the effects of rice straw incorporation by cutting height on paddy soil fertility. The average residual amount of rice straw by cutting height were showed 1,420 kg $ha^{-1}$, 1,850 kg $ha^{-1}$, and 2,400 kg $ha^{-1}$ for depths of 10 cm, 15 cm, and 20 cm, respectively. For soil physical properties, soil hardness and bulk density were decreased while porosity was increased by rice straw incorporation. But soil organic matter (SOM), available silicate content, and cation exchange capacity (CEC) were significantly decreased when rice straw was removed from the field. These results indicated that the SOM as residual amount of rice straw was influenced by level of cutting height. Milled rice yield was increased by 28% and 32% for cutting heights of 15 cm and 20 cm, compared with that of control, respectively. The number of spikelets per square meter and the percentage of ripeness were increased with increasing incorporation by lower level of cutting height of rice straw. Therefore, incorporation of rice straw practices under cutting method influenced soil improvement and rice yield in paddy field.

Physico-Chemical Properties of Paddy Soil and Actual Farming Conditions in Gyehwa Reclaimed Tidal Land (계화간척지 논토양의 물리화학적 특성 및 영농실태)

  • Yoo, Chul-Hyun;Yang, Chang-Hyu;Kim, Taek-Kyum;Ryu, Jin-Hee;Jung, Ji-Ho;Kang, Seung-Weon;Kim, Jae-Duk;Jung, Kwang-Yung
    • Korean Journal of Soil Science and Fertilizer
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    • v.40 no.2
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    • pp.109-113
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    • 2007
  • In order to establish the fertilization and soil management method in Gyehwa reclaimed tidal land, we investigated soil property and actual farming condition. Soil properties of 100 field paddy soil and farming surveys of 177 farm households were conducted. Average of effective soil depth was 17.8 cm, which was very smaller than the optimum level 50 cm. The hardness and bulk density of subsoil were $12.40kg\;cm^{-2}$ and $1.59g\;cm^{-3}$, respectively. These results showed that soil physical condition of Gyehwa reclaimed tidal land was very poor. Soil salinity ranged from 0.03 to 0.12%, and average of pH was 6.0, which implied that desalinization of Gyehwa reclaimed tidal land was progressed. However, soil nutrients in Gyehwa reclaimed tidal land were very unbalanced conditions as following, available phosphate $58mg\;kg^{-1}$, available silicate $85mg\;kg^{-1}$, cation exchangeable capacity $7.4cmolc\;kg^{-1}$ and organic matter $8.6g\;kg^{-1}$. On the farm household in Gyehwa reclaimed tidal land, fertilization amounts were $200-54-61(N-P_2O_5-K_2O)kg\;ha^{-1}$ They mainly practiced spring tillage(84%) rather than autumn tillage(16%), and only 14% of them applied rice straw annually in the paddy soil.