• 제목/요약/키워드: Grain filling

검색결과 288건 처리시간 0.029초

공압식 갱내충전을 위한 모형실험 연구 (A Study on the Model Test for Pneumatic Mine-Filling)

  • 양인제;신동춘;윤병식;목진호;김학성;이상은
    • 터널과지하공간
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    • 제24권6호
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    • pp.449-463
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    • 2014
  • 국내의 경우 슬러리나 페이스트 형태로 수압식 충전에 대한 연구와 다양한 폐광산 현장에 적용한 사례는 많으나, 공압식 충전에 대한 연구는 진행되지 않고 있다. 기존의 공압식 충전법은 강관의 구부러진 곳에서 충전재 유동에 의한 마모에 의해 강관의 손상이 발생한다. 이와 같은 문제점을 개선하기 위하여 새로 고안한 개량형 노즐을 이용한 공압식 충전법을 개발하였다. 본 연구에서는 접근이 가능하거나 불가능한 채굴공동을 모사하여 실험실에서 모형실험을 수행하고 그 충전효율을 평가하였다. 갱내 충전법 실험에서는 토출각의 변화, 모래의 투입량 및 입자 크기에 따라 충전효율을 분석하였으며, 지상 충전법 실험에서는 중력식, 재래식 및 개량형 충전방법의 실험으로부터 충전효율을 분석하여 개량형 공압식 충전법의 우수성을 입증하였다.

Changes of Sesamin and Sesamolin Contents of Sesame Seeds during Grain Filling in Different Sowing Dates

  • Shim Kang-Bo;Kang Churl-Whan;Lee Yu-Young
    • 한국작물학회지
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    • 제50권spc1호
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    • pp.167-170
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    • 2005
  • To obtain some information on the change of antioxidant components of seeds during grain filling stage as affected by the sowing dates, lignan compounds were investigated according to days of flowering under different sowing dates. Sesamin and sesamolin contents showed significantly different by days of flowering and varieties. Both of sesamin and sesamolin content increased after flowering and reached highest at 40 days of flowering, but they started to decrease thereafter, Sesamin and sesamolin contents of sesame seeds changed with sowing dates. Generally, late sowing date of May 30 showed relatively higher accumulation rate of sesamin and sesamolin contents rather than other sowing dates, but overall patterns were a little different by varieties and lignan compounds. In Yangbaekkae, sesamin and sesamolin contents showed relatively higher at sowing date of May 30, but Yanghuckkae showed higher sesamin and sesamolin contents till 20 days of flowering when sowing date of May 30, but it showed to change that both lignan contents were relatively higher under sowing date of May 10.

Quantifying rice spikelet sterility on Vietnamese cultivars (Oryza sativa L.) under high temperature and shading condition

  • Tran, Loc Thuy;Shaitoh, Kuniyuki
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.43-43
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    • 2017
  • During grain filling period, rice is affected by many environmental factors; including temperature, water, radiation and soil nutrition condition. In future climate, greater shading and heat tolerance will be required in rice. In this study, the effect of shading and high temperature on spikelet sterility was conducted on fourteen Vietnamese cultivars. Field experiments were studied in 2015 and 2016 to evaluate the response of Vietnamese cultivars under high temperature during grain filling stage. The high temperature and shading were applied by closing two sides of growth chamber and covered by a black cloth (50% reduced solar radiation) under the field condition after the first cultivar heading. The sterility increased significantly under high temperature and shading. The highest percentage sterile spiketlets was observed in 'Jasmine 85' (71.7%) under shading and in 'OM4900' (53.4%) under high temperature in 2015 and 2016, respectively. Among the treatments, the percentage of sterile spekelets in Vietnamese cultivars under shading was highest which was 54.9% and 41.8% in 2015 and 2016, respectively. Yield components reduced significantly in both of shading and high temperature. Corresponding with significantly decrease in yield components, the yield in high temperature and shading decreased strongly in both 2015 and 2016.

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영남평야지에서 벼 이앙시기에 따른 도정특성 변화와 도정특성 유망 유전자원 탐색 (Changes of Milling Quality of Rice Varieties According to the Transplanting Time and Good Resources with High Milling Quality in Yeongnam Plain Paddy)

  • 김춘송;이종희;곽도연;전명기;강종래;여운상;신문식;오병근
    • 한국작물학회지
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    • 제53권spc호
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    • pp.1-8
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    • 2008
  • 본 연구는 30개의 고품질 벼 품종을 공시하여 영남 남부 평야지에서 이앙시기의 차이가 도정특성에 미치는 영향을 살펴보고, 우리나라에서 재배되는 고품질 벼 품종 중에서 도정특성이 우수한 유전자원을 탐색하고자 수행하였으며, 그 결과는 다음과 같다. 1. 만기(6월 20일) 이앙시 보통기 이앙에 비하여(6월 5일) 출수가 6일 늦어지면서 등숙율과 백미 완전립비율, 완전미 도정수율이 증가하여 수당립수의 감소에 따른 쌀수량의 차이가 컸음에도 불구하고 완전미 쌀수량은 유의적인 차이가 없었다. 2. 현미 선별체를 이용한 현미립의 두께에 따른 분포특성은 보통기 이앙에 비하여 만기 이앙에서 $1.6{\sim}1.9\;mm$ 두께의 현미립이 줄고, 1.9 mm 이상 두께의 현미립이 증가하여 균일도가 향상되었다. 3. 보통기와 만기 이앙간에 도정 손실율의 차이는 없었으나, 도정에 소요되는 시간이 만기 이앙에서 증가하였다. 4. 도정특성이 우수한 유망유전자원으로 남평벼, 일미벼, 추청벼, 동진벼, 호평, 말그미, 칠보, 히노히까리, 청무 등 9품종을 선정하였다. 5. 등숙율은 추청벼, 동진벼, 밀양 205호가 90% 이상으로 가장 양호 하였으며, 백미 완전립비율은 남평벼가 95%로서 가장 좋았고, 완전미 쌀수량은 남평벼와 일미벼가 500 kg/10a 이상으로 가장 높았다.

CoO 소결체의 전기장에 의한 미세구조 변화 (Microstructure Evolution in Sintered CoO under Electric Fields)

  • 이기춘;유한일
    • 한국세라믹학회지
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    • 제29권11호
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    • pp.912-918
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    • 1992
  • Microstructure evolution including morphological change in the vicinity of the electrodes, porosity change and grain boundary migration was observed in polycrystalline CoO subject to electric fields at 1100 and 121$0^{\circ}C$ in air. At the cathode, the transported cations react with oxygen in the surrounding to form new lattices, while, at the anode, the reverse reaction occurs leading to lattice annihilation. Lattice formation also takes place at the surface of pores near the cathode inducing pore-filling effect. Grain boundary migration was found bo be enhanced or retarded depending on the field direction. It is therefore implied that the driving force of grain boundary migration is the vectorial sum of the curvature-induced chemical potential gradient and the electric field applied.

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Patterns between wall pressures and stresses with grain moisture on cylindrical silo

  • Kibar, Hakan
    • Structural Engineering and Mechanics
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    • 제62권4호
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    • pp.487-496
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    • 2017
  • The focus of this study were to investigate patterns between wall pressures and stresses with grain moisture of soybean and rice varieties widespread cultivated in Turkey in order to determine needed designing parameters for structure analysis in silos at filling and discharge. In this study, the wall pressures and stresses were evaluated as a function of moisture contents in the range of 8-14% and 10-14% d.b. The pressures and von Mises stresses affected as significant by the change of grain moisture content. The main cause of pressure and stress drops is changed in bulk density. Therefore is extremely important bulk density and moisture content of the product at the structural design of the silos. 4 mm wall thickness, were determined to be safe for von Mises stresses in both soybean and rice silos is smaller than 188000 kPa.

비료의 장기연용이 벼의 생육, 수량 및 미립발달에 미치는 영향 (Effects of Long Term Fertilizers on Growth, Yield and Grain Development of Rice)

  • 한희석;심재성
    • 자연과학논문집
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    • 제5권1호
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    • pp.15-28
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    • 1992
  • 토양에 20년간 3요소+생고를 처리하였을때 토양의 화학적 성분, 공극율, 입단구조가 잘 발달되었다. 또한 이 처리에 의하여 CGR은 영화분화기때 가장 높았으나 무처리구나 3요소단용구에서는 전생육기간을 통하여 계속 증가하는 경향을 띈 반면 3요소+생고처리구에서는 영화분화기이후 계속 감소 하는 추세을 나타내고 있다. 현미수량에 있어서는 3요소+생고처리에 의하여 11%의 증가효과가 있었으며 이것은 주로 이삭의 일.이차기경의 분화수가 증가하였기 때문이었다. 또한 미립형태에 있어서도 완전미의 비율이 높았는데 이것은 등숙속도와 매우 밀접한 관계가 있어서 등숙속도가 빠를수록 심백미, 복백미 및 동할미가 많았다. 3요소 + 생고속도는 40DAH이었다.

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Experiments on granular flow in a hexagonal silo: a design that minimizes dynamic stresses

  • Hernandez-Cordero, Juan;Zenit, R.;Geffroy, E.;Mena, B.;Huilgol, R.R.
    • Korea-Australia Rheology Journal
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    • 제12권1호
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    • pp.55-67
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    • 2000
  • In this paper, an experimental study of the rheological behavior of granular flow in a new type of storage silo is presented. The main characteristic of the new design is a hexagonal shape chosen with the objective of minimizing the stresses applied to the stored grains, and to reduce grain damage during the filling and emptying processes. Measurements of stress distribution and flow patterns are shown for a variety of granular materials. Because of the design of the silo, the granular material adopts its natural rest angle at all times eliminating collisional stresses and impacts between grains. A homogeneous, low friction flow is naturally achieved which provides a controlled stress distribution throughout the silo during filling and emptying. Secondary dynamic stresses, which are responsible for wall failure in conventional silos of the vertical type, are completely eliminated. A comparison between the two geometries is presented with data obtained for these silos and a number of granular materials. The discharge pattern inhibits powder formation in the silo and the filling system virtually eliminates unwanted material packing. Finally, notwithstanding the rheological advantages of this new design, the hexagonal cells that constitute the silo have many other advantages, such as the possible use of solar energy to control the humidity inside them. The cell type design allows for versatile storage capabilities and the elevation above the ground provides unlimited transportation facilities during emptying.

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