• KOREAN JOURNAL OF CROP SCIENCE
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• v.12
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• pp.31-36
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• 1972

These studies were carried out to find out the proper plant spacing and the optimum amount of nitrogen for maximum yield, on the occasion of early planting with creen vegetable (soybean for cook with rice) at the low temperature in early spring. The plant spacing were applied in 5 levels (50cm$\times$5cm, 50cm$\times$10cm, 40cm$\times$10cm, 30cm$\times$10cm and 30cm$\times$20cm) and the amount of nitrogen were applied in 4 levels (non, standard, twice and triple-amount), The triple super phosphate and potassium chloride were applied only in standard amount. The promotion of flowering was practised by the short-day treatment for 10 days (11 hr. a day). The variety examined was the early maturing one, HOKKAI # 1. and the results are as follow. 1. The plant spacing for maximum yield by the promotion of branch, pod and garin per a plant recognized the fact that there were 2 levels (50cm$\times$10cm and 30cm$\times$20cm planting method) and the maximum yield by the promotion of pod and grain per area showed the fact that there were 2 levels (50cm$\times$5cm and 30cm$\times$10cm planting method) in narrow planting method. 2. The optimum amount of nitrogen applied for maximum yield of pod and grain per area recognized w hat was sufficient as standard amount.

• Journal of Photoscience
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• v.9 no.2
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• pp.166-169
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• 2002

This paper is a part of the research into effects of increased UV-B (Ultraviolet-B, 280-320nm) upon the ecosystem of field wheat. Based on a 3-year project with intensified UV-B influencing the crop, observation and calculation were made of such factors and parameters as the morphology of a single wheat plant including its leaf area, leaf base angle and proportion of spacing between joints. The results show that the enhanced UV-B signifantly decreased wheat's SSLA, and the increased percentage of the lower LAI is associated with the change in leaf base angle and proportion of spacing between joints.

• Korean Journal of Medicinal Crop Science
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• v.5 no.2
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• pp.95-101
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• 1997

This study was conducted to investigate how a labor saving for conventional hand sowing and respond to major agronomic traits under different planting density in 1993 and 1994. Each trial was a randomized block split plot with row spacing as the main plots and hill spacing as subplots. Sowing rate appeared lower in 20 or 25cm hill spacing using machine seeder than in hand sowing. Sowing time required reduced more 121 hours per hectare in 60cm row, 20cm hill spacings using machine seeder than in hand sowing. Increasing row and hill spacings reduced number of seedling stand per unit $area(m^2)$. Both number of pods per plant and grain weight per plant and showed highly increase in wide planting. Best yield obtained in 60cm row, 20cm hill spacing using machine seeder. Accumulative mean air temperature was positively correlated with stem height, number of pods per plant and yield, otherwise accumulative rainfall was negatively correlated with ones. A highly significant negative correlation was showed between number of seedling stand per unit $area(m^2)$ and number of branches, number of pods per plant, grain weight per plant and yield. Yield was positively correlated with number of branches, number of pods per plant and grain weight per plant.

• Journal of Biosystems Engineering
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• v.37 no.5
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• pp.314-318
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• 2012

Purpose: This study was conducted to develop a measurement system for determining photosynthetic photon flux (PPF) distribution and illumination efficiency of LED lamps. Methods: The system was composed of a linear moving sensor part (LMSP), a rotating part to turn the LMSP, a body assembly to support the rotating part, and a motor controller. The average PPF of the LED lamp with natural cooling and water cooling was evaluated using the measurement system. Results: The PPF of LED lamp with water cooling was 3.1-31.7% greater than that with natural cooling. Based on the measured value, PPF on the horizontal surface was predicted. Illumination efficiency of the LED lamp was slightly increased with water cooling by 3.4%, compared with natural cooling. A simulation program using MATLAB was developed to analyze the effects of the vertical distance from lighting sources to growing bed, lamp spacing, and number of LED lamps, on the PPF distribution on the horizontal surface. The uniformity of the PPF distribution of the LED lamps was fairly improved with 15 cm spacing, as compared to the 5 cm spacing. By simulation, PPF of $217.0{\pm}27.9{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ was obtained at the vertical distance of 40 cm from six LED lamps with 12 cm spacing. This simulated PPF was compared to the measured one of $225.9{\pm}25.6{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. After continuous lighting of 346 days, the relative PPF of LED lamps with water cooling and natural cooling was decreased by 6.6% and 22.8%, respectively. Conclusions: From these results, it was concluded that the measurement system developed in this study was useful for determining PPF and illumination efficiency of artificial lighting sources including LED lamp.

• Korean Journal of Materials Research
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• v.29 no.6
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• pp.349-355
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• 2019

This study deals with the microstructure and tensile properties of 600 MPa-grade seismic reinforced steel bars fabricated by a pilot plant. The steel bar specimens are composed of a fully ferrite-pearlite structure because they were air-cooled after hot-rolling. The volume fraction and interlamellar spacing of the pearlite and the ferrite grain size decrease from the center region to the surface region because the surface region is more rapidly cooled than the center region. The A steel bar specimenwith a relatively high carbon content generally has a higher pearlite volume fraction and interlamellar spacing of pearlite and a finer ferrite grain size because increasing the carbon content promotes the formation of pearlite. As a result, the A steel bar specimen has a higher hardness than the B steel bar in all the regions. The hardness shows a tendency to decrease from the center region to the surface region due to the decreased pearlite volume fraction. On the other hand, the tensile-to-yield strength ratio and the tensile strength of the A steel bar specimen are higher than those of the B steel bar with a relatively low carbon content because a higher pearlite volume fraction enhances work hardening. In addition, the B steel bar specimen has higher uniform and total elongations because a lower pearlite volume fraction facilitates plastic deformation caused by dislocation slip.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.2
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• pp.167-176
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• 1999

Shoot morphological characteristics were affected by plant population densities in alfalfa. Shoots per plant, yield per shoot, yield per plant, and stem diameter increased with decreasing alfalfa population density. Winter survival was maximized at a plant population of $45plants\;m^{-2}$ or less. The grams of TNC per root increased as the stand density decreased. The lowest LT 50 occurred at the lowest stand density ($16plants\;m^{-2}$ having 25 cm plant spacing) and the highest LT 50 was attained at the highest stand density($494plants\;m^{-2}$ having 4.5 cm plant spacing). There were no differences in shoot morphology, winter survival, and cold hardiness in between 'Algonquin'and 'Vernal'. From this study, high stand density of alfalfa ($278plants\;m^{-2}$ or more) appears to be of little advantage compared to low stand density in terms of winter survival and cold hardiness.

• Korean Journal of Medicinal Crop Science
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• v.3 no.2
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• pp.135-139
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• 1995

In order to determine the optimum planting density of Perilla frutescens which is suitable for the southern part of Korea, agronomic characters, yield of fresh stem, leaf and seed, and yield components were investigated grown in 1985 and 1986 at Mokpo Branch Station of Crop Experiment Station. The heading date was Aug. $14{\sim}15$ and the blooming period was Aug. $19{\sim}21$ regardless of the difference of plant density, but the longest stem length was 135cm in the plant density of $70{\time}40cm$ and the stem length in the plant density of $80{\time}40cm$ was 134cm. The quantity of fresh weight of stem and leaf and fresh weight of seed was high as 531kg/l0a in the plant density of $80{\time}40cm$. The positive correlation such as $0.7315^*,\;0.9024^{**}\;and\;0.7425^*$ were found between stem length and fresh weight of stem and leaf, stem length and fresh weight of seed, fresh weight of stem and leaf and fresh weight of seed and so high significance was recongnized. In the verification of significance of row spacing, the disperse of the stem length was $55.67^{**}$, that of fresh weight of stem and leaf is $268.50^*$, theat of fresh weight of seed was $16.00^{**}$ and high significance was recognized. In the verification of significance of intrarow spacing, the diperse of stem length was $54.21^{**}$, that of fresh weight of stem and leaf was $2,582.00^{**}$, that of fresh weight of seed was $48.00^{**}$ and then high significance was recognized. Accordingly, the proper plant density of perilla frutescens was 80cm of row $spacing{\time}40cm$ of intrarow spacing.

• Proceedings of the Korean Society of Crop Science Conference
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• 1994.06a
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• pp.136-137
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• 1994

• 한국약용작물학회:학술대회논문집
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• 2008.05a
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• pp.83-84
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• 2008

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.4
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• pp.378-383
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• 2018

The goal of this study was to examine the growth and yield according to planting density in wide-row drill seeding cultivation suitable for mechanized harvesting. We evaluated effects depending on planting densities [row spacing (30, 40, 50, and 60 cm) and plant spacing (10, 15, and 20 cm)] and cultivars ('Hongeon' and 'Arari') on growth and yield of Adzuki Beans (Vigna angularis (Willd.) Ohwi Ohashi). When row spacing decreased, the stem length increased in 'Arari' but decreased in 'Hongeon.' The stem diameter and number of branches in both the cultivars decreased with a decrease in row spacing. The pod height increased with lower planting densities. The greatest height values recorded in 'Hongeon' and 'Arari' were 5.0 cm and 8.8 cm in $30{\times}10cm$ and $50{\times}10cm$ treatments, respectively. The number of pods and number of seeds in both cultivars tended to increase with a decrease in planting density. On the other hand, in 100-seed weight, there was a difference in planting density in 'Hongeon', but no difference in 'Arari'. The highest yield was at the planting density of $40{\times}15cm$ in both 'Hongeon' and 'Arari', $285kg{\cdot}10a^{-1}$ and $374kg{\cdot}10a^{-1}$.