• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.503-507
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• 2021

Sodium borohydride, NaBH₄, has many advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFC). When PEMFC is used outdoors as a transport type, it is economical to hydrolyze NaBH₄ using fresh water instead of distilled water. Therefore, in this study, hydrogen was generated using fresh water instead of distilled water during the NaBH₄ hydrolysis process. The properties of NaBH₄ hydrolysis were studied using an activated carbon-supported Co-P-B/C catalyst. Fresh water did not generate tetrahydrate during the NaBH₄ hydrolysis process, and distilled water produced tetrahydrate by-products, which consumed a lot of water during the hydrolysis process, indicating that at the end of the reaction at a high concentration of 25% or more of NaBH₄, dry by-products and unreacted NaBH₄ remained. As a result, when fresh water was used, the hydrogen yield and hydrogen generation rate were higher than that of distilled water at a high concentration of 25% or more of NaBH₄, indicating that it is suitable for use in transport-type fuel cells such as unmanned aerial vehicles.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.1
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• pp.49-54
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• 1987

Information is needed on the plant characteristics affects by forage removal and their relationships to grain yield of italian ryegrass in order to combine herbage seed crop management and livestock farming. This study with tetraploid cv. Tetrone was carried out on the experimental field of Haenam Branch Station. treatments included two different seeding time, cutting time and frequency. Seeds were sown in row 50 cm width within the rows. The results are summarized as follows: 1. Fresh and dry matter were increased significantly in plots defoliated lately and many times but seed yield components were decreased significantly in plots defoliated in spring. 2. Autumn defoliation had no significant effect on the seed yield but seed yield were decreased significantly in plots defoliated later than 8 April. 3. Excess vegetative growth can be removed in autumn and early spring without harm to the seed crop and the most important aspect of its removal is the timing of the operation. 4. Seed yield reductions were accompanied by the decrease of inflorescences,seeds/spike, and thousand seeds weight, due to an increase in apex removal of vigorous tillers by late cutting.

• Journal of Animal Science and Technology
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• v.48 no.1
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• pp.115-122
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• 2006

This experiment was conducted to evaluate the effect of tillage system and fertilizer type on the forage yield, quality, and production cost of winter rye. This experiment was a 2×2 factorial arrangement for two tillage system (Tillage and No-tillage) and two fertilizer type (Chemical and Manure compost). There was no difference in dry matter (DM) content, TDN (total digestible nutrients) yield, and CP (crude protein) yield of rye, but the DM yield was significantly higher for rye in tillage compared to the no-tillage system. The use of chemical fertilizer type also showed significant increase in DM, TDN and CP yields compared to the use of manure compost as fertilizer. The CP content for rye was significantly higher in no-tillage compared to tillage system, but the type of fertilizer used has no significant effect. No significant effects were observed for NDF (neutral detergent fiber), ADF (acid detergent fiber), and TDN in tillage system and fertilizer type of rye. The total cost to prepare 1 ha is lower in no-tillage compared to tillage, but production cost in rye per kg of fresh, DM and TDN were almost the same as tillage system because of lower forage production. The total cost to prepare 1 ha with the use of chemical fertilizer was higher than using manure compost as fertilizer, however, the cost to produce 1 kg of fresh, DM and TDN were lower when using chemical as fertilizer because of higher yield. Based on the results of this study, tillage system and fertilizer type affected forage yield more than forage quality. Production cost per 1 kg of tillage was lower compared to no-tillage, and that of chemical was lower than manure because of higher forage yield.

• Journal of Biosystems Engineering
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• v.43 no.2
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• pp.138-147
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• 2018

Purpose: A narrowband hyperspectral imaging sensor of high-dimensional spectral bands is advantageous for identifying the reflectance by selecting the significant spectral bands for predicting crop yield over the broadband multispectral imaging sensor for each wavelength range of the crop canopy. The images acquired by each imaging sensor were used to develop the models for predicting the Chinese cabbage yield. Methods: The models for predicting the Chinese cabbage (Brassica campestris L.) yield, with multispectral images based on unmanned aerial vehicle (UAV), were developed by simple linear regression (SLR) using vegetation indices, and forward stepwise multiple linear regression (MLR) using four spectral bands. The model with hyperspectral images based on the ground were developed using forward stepwise MLR from the significant spectral bands selected by dimension reduction methods based on a partial least squares regression (PLSR) model of high precision and accuracy. Results: The SLR model by the multispectral image cannot predict the yield well because of its low sensitivity in high fresh weight. Despite improved sensitivity in high fresh weight of the MLR model, its precision and accuracy was unsuitable for predicting the yield as its $R^2$ is 0.697, root-mean-square error (RMSE) is 1170 g/plant, relative error (RE) is 67.1%. When selecting the significant spectral bands for predicting the yield using hyperspectral images, the MLR model using four spectral bands show high precision and accuracy, with 0.891 for $R^2$, 616 g/plant for the RMSE, and 35.3% for the RE. Conclusions: Little difference was observed in the precision and accuracy of the PLSR model of 0.896 for $R^2$, 576.7 g/plant for the RMSE, and 33.1% for the RE, compared with the MLR model. If the multispectral imaging sensor composed of the significant spectral bands is produced, the crop yield of a wide area can be predicted using a UAV.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.38-43
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• 1999

Over 2,000 ha of rice fields in the western and southern coastal region of Korea were flooded with sea water during the spring tide, on August 19-21, 1997, and the rice plant at heading stage was injured. The field surveys were undertaken at the sea water flooded paddy fields in Chonbuk Province, to identify the injury symptoms and rice yield damage subjected to different flooding condition and desalinization methods. Five days after sea water flooding at heading stage, the flag leaves of rice plants flooded with 30 ㎝ deep sea water withered from the tip, the withering progressed to the lower leaves in deeper flooding. The spikelets were spotted black and discolored from the tip at 50 ㎝ deep flooded rice, and some panicles changed to white at 80 ㎝ deep flooded rice. Most of the rice leaves submerged completely for an hour were withered and most of panicles changed to white. The milled rice yield, percentage of ripened grain, and 1000 grain weight of flooded rice decreased with deeper flooding water, higher water salinity and longer flooding time. Even under the same flooding conditions, the damage of rice yield varied with the growth stage: heading stage>dough stage>booting stage. Rice yield damage was less in the fields on the upper riverside than those of the fields on the estuary and seaside, because of lower water salinity. In a flooded field, the rice yield damages were reduced as the distance increased from the levees where the sea water inflowed and increased as the distance increased from the fresh water irrigation gate. The desalinization treatments consisting of frequent exchange of irrigation water and spraying with fresh water soon after flooding effectively reduced the rice yield damage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.277-286
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• 1985

From a series of studies conducted on the local maize lines at the Agr. College of the Chungnam National Univ., a few maize lines with many tillers and ears per plant were identified and tentatively named as MET. The purpose of the study was to evaluate the MET lines, which were selfed for five generations, for silage purpose under the different plant densities. A hybrid, Suwon #19 and a synthetic variety, Puyo #3${\times}$#2, were included for comparison. Plant height at harvesting times showed no significant varietal differences. However, the MET lines were very slow in early plant growth compared to the hybrid or synthetic variety, probably due to inbreeding depression of the MET lines. Total fresh weight at the harvesting times was highest in the MET 1 line. The MET 1 line was about 2,000 kgr. per 10a. higher than the hybrid at the harvesting time. The highest fresh weight was obtained when grown under the plant density of 60 ${\times}$ 20cm. Total dry weight per unit area showed the same tendency as the fresh weight. Total dry weight of MET 1 line was about 2.4 tons per 10a., which was about 10% higher than the hybrid, Suwon #19. As the fresh weight, the total dry weight was also highest in the plant density of 60 ${\times}$ 20cm. The grain yield per 10 are of MET 1 was comparable to the grain yield of the hybrid, especially in the low plant density, 60 ${\times}$ 40cm. The average number of effective tillers of MET lines were 4.5, while the mean tiller number of the hybrid or synthetic variety were none. However, the lodging was one of the problem for growing MET lines. The 100 kernel weight of MET lines was about 9 gr., while the 100 kernel weight of the hybrid or synthetic variety was about 30 grm.

• Korean Journal of Plant Resources
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• v.6 no.2
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• pp.147-154
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• 1993

The experiment was carried out to study the influence of seeding dates, planting densities and fertilizer application levels on some agronmic characters and yield of fresh weight in Agastache rugosa. The results obtained are summarized as follow; Fresh weight was increased on Apr. 1 seeding date. Therefore, optimum time for sowing was on Apr. 1. Stem length was long in dense planting and short in spacious planting. Stem diameter was thick in spacious planting, and was thin in dense planting. Yield was higher in dense planting densities($10{\times}20cm:50\;plants/m^2,\;20{\times}20cm:25\;plants/m^2,\;(30{\times}20cm:17\;plants/m^2$) Fertilizing ($N:P_2O_5;K_2O=6:6:6kg/10a$) was increased than without fertilizing because stem length and number of leaf were good.

• Korean Journal of Plant Resources
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• v.16 no.2
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• pp.118-122
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• 2003

These studies were carried out to clarify the effects of black P.E. mulching and planting density on the growth and rhizome yield of Jihwang #1, a new high yielding Rehmannia glutinosa variety. Emergence ratio was higher 3.1％ in mulching than in non-mulching, but was not affected by planting density. Plant height and fresh leaf weight per plant were increased by mulching and at lower planting density. However, the fresh leaf weight per unit area was increased at higher planting density. Dry rhizome weight was increased 28% in mulching than that of non-mulching. Dry rhizome weight per plant was increased, but that of per unit area was decreased at lower planting density.

• New & Renewable Energy
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• v.2 no.4 s.8
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• pp.70-77
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• 2006

The butane decomposition over the catalyst is an attractive method for the hydrogen production. The objective of the work was investigated the catalysis of carbon black in butane decomposition reaction. The Butane decomposition was performed over carbon black catalyst in a range of $500-1100^{\circ}C$. The butane conversion of thermal decomposition and catalytic decomposition were increased with increasing the reaction temperature The butane conversion of the thermal decomposition was higher than the butane conversion of the catalytic decomposition. Hydrogen and methane were mostly observed in the butane decomposition over $1000^{\circ}C$. Especially, the hydrogen yield was steadily increased with raising the reaction temperature, It could be known that the hydrogen yield of the catalytic decomposition was higher than one of the thermal cracking because the hydrogen productivity was improved by the catalyst. The deactivation of the catalyst was not observed in the reactivity test. The surface and crystalline of the fresh and used catalysts were characterized by TEM, BET surface area and XRD analysis, respectively. The fresh carbon black particles had mostly smoothly round-shaped surfaces. In the surface of the carbon black after the reaction, the deposited carbon was formed as the protrusion-shaped carbon and the cone-shaped. The proper peaks of carbon black appeared in XRD analysis.

• Food Science and Preservation
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• v.9 no.1
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• pp.97-101
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• 2002

Antimicrobial and antioxidative activities of various solvent extracts from different parts of the loquat were investigated to process it as the functional food. The extraction yield showed higher in butanol fraction of 4.95% in peel and 4.42% in seed than others, but water fraction showed high extraction yield of 3.89% in leafs 23.6% in the seedless fruit and 21.1% in fresh, In the antimicrobial activity test, ethyl acetate fraction that leaf and fruit excluded seed inhibited higher 19, 15 mm and 16, 15 m in clear zone far Staphylococcus aureus and Escherichia coli in each. Ethyl acetate fraction that extracted from a series of polar and nonpolar solvent fractionation of methanol extracts showed better results in the hydrogen donating activity of 82% in leaf, 74% in seedless fruit, 68% in seed, 52% in peel and 30% in fresh.