• Journal of Biosystems Engineering
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• 제16권1호
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• pp.37-48
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• 1991

Rice plants are subjected to various forces such as natural force of wind and mechanical force of cultivating machines. Rheological behavior of the rice stem can be expressed in terms of three variables : stress, relaxation and time. The objectives of this study are to examine stress relaxation, creep and recovery characteristics on the rice stem in case of axial and radial loading. Stress relaxation with time was studied on three levels of loading rate and on four levels of applied stress. The results were summarized as follows : 1. The hysterisis losses of the rice stem distinctly observed at the radial compression in comparison with axial compression. The hysterisis loss implied that the stem to absorbed energy without being deformed beyond the yield point. 2. Ageneralized Maxwell model consisting of three elements gave a good description of the relaxation behavior of the rice stem. Rate of loading was more significant on the observed relaxation behavior within the short relaxation time, but there were little influences of rate of loading on the relaxation time. 3. The stress relaxation intensity and the residual stress increased in magnitude as the applied stress increased, but the relaxation time was little affected by the applied stress. 4. The coefficients of the stress relaxation model showed much differences in the radial compression and the axial compression, especially the higher relaxation stress of the third element was observed in the radial compression. 5. The behaviors of rice stem in creep and recovery test also might be represented by a four element Burger's model. But the coefficients of the creep model were different from those of the recovery model. 6. The steady-state phenomena of creep appeared at the stress larger than 20 MPa in Samkang and 1.8 MPa in Whajin. 7. The elastic modulus of the stem showed the range from 40 to 60 MPa. It could be considered, as a result, the rice stems had viscoelastic properties.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.521-522
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• 2006

In this paper, hybrid air-water discharges were used to develop an optimal condition for providing a high level of water decomposition for hydrogen yield. Electrical and optical phenomena accompanying the discharges were investigated along with feeding gases, flow rates, and point-to-plane electrode gap distance. The primary focus of this experiment was put on the optical emission of the near UV range, with the energy threshold sufficient for water dissociation and excitation. The $OH(A^{2+},'=0\;X^2,"=0$) band's optical emission intensity indicated the presence of plasma chemical reactions involving hydrogen formation. In the gaseous atmosphere saturated with water vapor the OH(A-X) band intensity was relatively high compared to the liquid and transient phases although the optical emission strongly depended on the flow rate and type of feeding gas. In the gaseous phase discharge phenomenon for Ar carrier gas transformed into a gliding arc via the flow rate growth. OH(A-X) band's intensity increased according to the flow rate or residence time of He feeding gas. Reciprocal tendency was acquired for $N_2$ and Ar carrier gases. The peak value of OH(A-X) intensity was observed in the proximity of the water surface, however in the cases of Ar and $N_2$ with 0.5 SLM flow rate peaks shifted to the region below the water surface. Rotational temperature ($T_{rot}$) was estimated to be in the range of 900-3600 K, according to the carrier gas and flow rate, which corresponds to the arc-like-streamer discharge.

• 한국토양비료학회지
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• 제9권4호
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• pp.245-250
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• 1976

율무의 재배(裁培)에서 시비량(施肥量)을 결정(決定)하는 기초(基礎) 자료(資料)를 얻기 위하여 포장시험(圃場試驗)을 실시(實施)한 결과(結果)는 다음과 같았다. 1. N, $P_2O_5$, $K_2O$, 를 0-0-0, 6-3-3, 12-6-6 및 18-9-9kg/10a로 증가(增加)시킬 때 율무의 수량(收量)은 직선적(直線的)으로 증가(增加)했다. 2. NPK 중 다른 두 성분의 수준(水準)을 제삼수준(第三水準), 즉 N는 12kg/10a, $P_2O_5$ 및 $K_2O$는 6kg/10a로 고정(固定) 시키고 비료(肥料) 수준별(水準別) 수량(收量)을 보면 NPK의 제삼수준(第三水準)(N는 12kg/10a, $P_2O_5$ 및 $K_2O$는 6kg/10a)에서 최고(最高) 수량(收量)이 되고 그 이상(以上)에서는 수량(收量)이 감소(減少)했다. 3. 따라서 본시험(本試驗)만으로는 율무의 삼요소적량(三要素適量)을 지적(指摘)해 낼 수 없어 시비량(施肥量)을 늘려 새로운 시험(試驗)을 실시(實施)할 필요(必要)가 있다. 그러나 본시험(本試驗)에 쓰인 것과 유사(類似)한 토양(土壤)에서는 N, $P_2O_5$, $K_2O$를 18-9-9 kg/10a 이상(以上) 시용(施用)해도 수량(收量)이 증가(增加)할 수 있음을 알 수 있다. 4. 식물체(植物體)의 N와 K의 흡수면(吸收面)에서는 두 성분(成分) 간(間)에 배항작용(培抗作用)이 있음이 관찰(觀察)됐다.