• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.3
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• pp.229-238
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• 2018

The purpose of this study was to evaluate the effects of nitrogen fertilization amount and timing of application on protein content, dough properties, change in protein fraction, and bread loaf volume for Korean wheat cultivars, Baekkang, Joongmo2008, and Saekeumkang, for bread with a superior gluten composition during the grain filling stage. Protein content increased with an increase in the amount of N and timing of application. The SDS segmentation volume (SDSS) increased with an increase in N, but there was no effect of the timing of N application on SDSS. An increase in N amount and timing of application caused a difference in dough properties, such as water absorption, mixing time, and tolerance, among the cultivars. Soluble and insoluble polymeric and monomeric protein contents increased with an increase in N amount and timing of application the three Korean wheat cultivars. The effects of N amount and application timing on bread loaf volume (BLV) varied among the cultivars. The BLV of Saekeumkang increased regardless of the N amount and timing of application, but that of Baekkang and Joongmo2008 cultivars was reduced. However, there was a positive correlation between protein content with the addition of N fertilization and BLV. In addition, SDSS, mixing time, and protein fractions were positively correlated with BLV. Since the response of fertilizer conditions was different for each wheat cultivar, it is necessary to build a suitable fertilizing system for each of them. Additionally, since the environment is changing, such as abnormal climate during the maturing period, research is needed to establish appropriate fertilizer conditions for varieties of bread wheat.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.1-13
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• 2006

Response of grain yield and milled-rice protein content to nitrogen topdress (N) timing at panicle initiation stage (PIS) is critical for quantifying real-time N requirement for target grain yield and milled-rice protein content. Two split-split-plot experiments with three replications, one in 2004 and the other in 2005, were conducted in Experimental Farm, Seoul National University, Suwon, Korea. The experiments included three N rates at tillering stage (TS), three N timing treatments at panicle initiation stage (PIS) and two rice cultivars. The N rates at TS, N timing at PIS, and rice cultivars were randomly assigned to main plot, sub plot, and sub-sub plot, respectively. Results showed that the delayed N application at PIS reduced grain yield in 2004 and increased milled-rice protein content in both years significantly at 0.05 probability level. The calculated optimum N timing at PIS from pooled data by N rates and rice cultivars in two years was at 28 days before heading (DBH). However, real-time of N timing at PIS was dependent on plant growth and N status around PIS that in turn was dependent on applied N rates at TS. The optimum N timing at PIS was at 30 DBH for no N treatments at TS while at 27 DBH for 3.6 and 7.2 kg N/10a treatments and at 27 and 29 DBH for Hwaseongbyeo and Daeanbyeo, respectively. In general, earlier applied N at PIS resulted in lower milled-rice protein content but the highest grain yield was expected to be obtained when N topdress at PIS was applied at the time when shoot N concentration started to drop below about 23 mg/g due to dilution effect after transplanting. In conclusion, the results of our experiments imply that the currently recommended N topdress time (24DBH) at PIS in Korea should be reconsidered for the higher grain yield and the better quality of rice.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.4
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• pp.447-453
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• 2016

The reduction technologies of exhaust gas from both the off-road engine and on-road vehicles are important. It is possible to apply various combustion technologies with engines after the application of a treatment technology to this field. In this study, main injection timing, pilot injection timing, and exhaust gas recirculation (EGR) rate were selected as the experimental parameters whose effects on the emission of exhaust gases and on the fuel consumption characteristics were to be determined. In the experiment, the emission of nitrogen oxide (NOx) and Smoke, and the Torque at the same fuel consumption level, were measured. The experimental data were analyzed using the Taguchi method with an L9 orthogonal array. Additionally, analysis of variation (ANOVA) was used to confirm the influence of each parameter. Consequently, the level of each parameter was selected based on the signal-to-noise ratio data (main injection timing, 3; pilot injection timing, 3; EGR rate, 2), and the results of the Taguchi prediction were verified experimentally (error: NOx, 10.3 %; Smoke, 6.6 %; brake-specific fuel consumption (BSFC), 0.6 %).

• Horticultural Science & Technology
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• v.33 no.6
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• pp.845-853
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• 2015

The objective of this study was to predict the timing of nitrogen (N) demand through analyzing chlorophyll fluorescence (ChlF), soil-plant analysis development (SPAD), and normalized difference vegetation index (NDVI), which are positively correlated with foliar N concentration in star cluster (Pentas lanceolata). The plants were grown in potting soil under optimal conditions for 30 d, followed by weekly irrigation with five concentrations (0, 4, 8, 16, and 24 mM) of N for an additional 30 d. These five N application levels corresponded to leaf N concentrations of 2.62, 3.48, 4.00, 4.23, and 4.69%, respectively. We measured 13 morphological and physiological parameters, as well as the responses of these parameters to various N-fertilizer treatments. The general increases in Dickson's quality index (DQI), above-ground dry weight (DW), total DW, flowering rate, ${\Delta}F/Fm$', and qP in response to treatment with 0 to 8 mM N were similar to those of SPAD, NDVI, and Fv/Fm. Consistent and strong correlations ($R^2$= 0.60 to 0.85) were observed between leaf N concentration (%) and SPAD, NDVI, ${\Delta}F/Fm$', and above-ground DW. Validation of leaf S PAD, NDVI, and ${\Delta}F/Fm$' revealed that these vegetation indices are accurate predictors of leaf N concentration that can be used for non-destructive estimation of the proper timing for N-solution irrigation of P. lanceolata. Moreover, irrigation with 8 mM N-fertilizer i s recommended w hen leaf N concentration, SPAD, NVDI, and ${\Delta}F/Fm$' ratios are reduced from their saturation values of 4.00, 50.68, 0.64, and 0.137%, respectively.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.63-63
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• 2022

Wheat flour can be categorized into bread, all-purpose, cake flour according to its protein content. Since optimal wheat flour protein content is different for each end use, it is necessary to diversify the nitrogen fertilizer methods depending on the end use and cultivar. Optimal wheat flour protein content of soft wheat (for cake flour) is lowest (<=10%) among all end use, it is necessary to develop nitrogen fertilizer methods for high yield and low protein content. In order to analyze the yield and quality changes of soft wheat as nitrogen fertilizer amount and splitting timing, soft wheat cultivar 'goso' was sown on paddy soil in jeunju, Republic of Korea ('21.10). the amount of nitrogen fertilizer was divided into 4 levels by adjusting 2kg/10a increments from 5.1 to ll.lkg/lOa, and in the N 7.1 and 9.1 kg/1 Oa(standard) treatment, N amount divided into sowing date:regrowing stage=3:7,4:6(standard), 5:5. In regrowing stage, Tiller number and N fertilizer amount at sowing date showed a correlation; y=-121.14x²+792.66x-525.41 (R²=0.77^*, y: Tiller number/m², x: N amount at sowing date(kg/10a)). Tiller number in regrowing stage was the highest when the nitrogen fertilizer amount at sowing date was 3.23kg/10a. spike number per m² was the highest when N fertilizer was divided into sowing date:regrowing stage=3:7(N amount: 9.1kg/10a). If N fertilizer amount was fixed, grain yield was also the highest when N fertilizer was divided into sowing date :regrowing stage=3:7. Also, N amount at sowing date and grain yield showed no correlation, but N amount at regrowing stage and grain yield showed significant correlation. As N amount increased, protein content also showed a tendency to increase.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.178-185
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• 1998

To reduce the particulate matter and nitrogen oxides from diesel engine, many studies are proceeding and being accomplished practically. In this situation CNG engine has important meaning both as a clean fuel and an alternative energy. In order to present the direction and application of CNG, we simulated various operating conditions, that is, spark timing, compression ratio and fuel composition etc. Thus we try to understand how those affect performance and exhaust characteristics. The simulation program results found that the optimum combustion start angle was 21$^{\circ}$ at 1800rpm and fuel composition affects performance and emissions, also we could understand the formation of emission as crank angle is changed.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.670-675
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• 1999

The effect of fertilizer applicatioin on ponded and percolation water in paddies were evaluated at the field plots of the Chungbuk National University for irrigation period. The chemical fertilicers were applied to the study polts at an average application rate of 77, 110, 165kgN/ha, respectively. The concentration of T-N , T-P and COD in ponded water greatly depends on the amount and timing of fertilizer applied. Therefore, the decrease in the amount of fertilizer and proper water management may be needed to decrease in the amount of fertilizer and proper water management may be needed to reduce the runoff loading.

• Journal of Power System Engineering
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• v.20 no.2
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• pp.51-57
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• 2016

Non-esterified biodiesel fuel is cheaper than esterified that because of a simple manufacturing process that only consists of filtering. Applicability of this on diesel engine with electronic control system was accomplished, then optimization adopting a fractional factorial design and response surface methodology was carried out at 25% and 50% of engine load in this study. Pressure of common rail and injection timing mainly effected on responses as specific fuel oil consumption and nitrogen oxides regardless of engine load. Estimations were 310.3 g/kWh of specific fuel oil consumption and 237 ppm of nitrogen oxides at 25% load, and 233.2 g/kWh of specific fuel oil consumption and 730 ppm of nitrogen oxides at 50% load. Tests to verify these estimations were accomplished and as the results, specific fuel oil consumption was 300.4 g/kWh and NOx was 277 ppm at 25% load and 236.8 g/kWh and 573 ppm at 50% load.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.728-734
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• 2010

We studied the accumulation and partitioning of dry weight (DW) and nitrogen (N) in different parts of field-grown 'Fuyu' persimmon to elucidate that the foliar applications of supplemental N in June or September compared favorably with the traditional soil application in securing leaf area and fruit production. We also estimated the proportion of N permanently removed from the tree at the end of a growing season. Urea was applied either to leaves in June and/or September or to the soil in June and September for three consecutive years, and the trees were excavated in November for analyses. Total DW ranged from 4.2-4.8, 8.7-9.2, and 17.1-21.5 kg in a 4-, 5-, and 6-year-old tree, respectively, without statistical difference among the four treatments. Of the total DW, 3.3-10.2% was in shoots, 5.7-10.5% in leaves, 8.3-31.4% in aerial woods, 13.0-27.0% in root, and 28.0-59.3% in fruits. As the trees became more productive, DW proportion of fruits significantly affected that of the root: in 6-year-old trees, root DW accounted for only 10.6-15.8% of the tree total when fruit DW accounted for 50-60%. N contents ranged from 24.6-28.3, 48.3-53.5, and 98.3-122.6 g in a 4-, 5-, and 6-year-old trees, respectively, without statistical difference among the treatments. Of the total N, 6.2-11.5% was in shoots, 16.7-24.3% in leaves, 17.6-23.5% in aerial woods, 17.2-37.5% in roots, and 16.9-34.4% in fruits. As in DW, the increase in the proportion of N in fruits decreased in the root most significantly. Application methods for supplemental N did not affect the proportion of DW and N removed from the tree through abscising leaves and harvested fruits. Percentage of DW removal was 41 in 4- and 5-year-old trees, but it was 61 in more productive 6-year-old trees; that of N was 39, 43, and 49%, respectively. No significant changes in the contents of DW and N in field-grown trees, as well as their percentages removed from the tree at the end of the season, demonstrated that foliar application of supplemental N was as good as soil applications with much less N.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.60-60
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• 2022

As various wheat variety for bread, all-purpose, and cake flour have been developed, suitable cultivation method for the end-use of the new variety need to be revised. This study was conducted to suggest an optimal nitrogen(N) fertilizer method for wheat Variety 'Saekeumgang' and 'Hojoong' with good noodle quality. In order to analyze the yield and quality changes of 'Saekeumgang' and 'Hojoong' as nitrogen fertilizer amount and timing, these varieties were sown on paddy soil in jeunju, Republic of Korea. The amount of N fertilizer was divided into 4 levels (7.1, 9.1 11.1,13.1kg/10a). In each levels, N amount in sowing date fixed as 3.6kg/10a, N amount in 10 days after heading(DAH) were treated 0 or 2kg/10a, and the other N amount was treated in regrowing stage. As N amount in regrowing stage increased, culm length of 'Saekkeumgang' was increased, but culm length of 'Hojoong' was not affected. Spike number/m² was increased when N fertilizer amount in regrowing stage increased as 3.5 to 7.5kg/10a. But, spike number/m² wasn't increased compared N amount 7.1kg/10a conditions when N fertilizer amount 9.1kg/10a. When the N fertilization amount in regrowing stage was increased by 1kg/10a, grain yield increased by 45.7 kg/10a in 'Saegeumgang' and 21.4kg/10a in 'Hojoong', so the fertilizer effect of 'Saegeumgang' was higher, when N fertilizer amount was increased to 2kg/10a at 10DAH, 1000-grain weight increased, but spike number/m2 and grain yield were not affected by N fertilizer at 10 DAH. Protein content and SDS-sedimentation value were increased as increasing N fertilizer amount in regrowing stage and 10 DAH. Among them, N fertilizer amount in 10 DAH had higher impact on protein content and SDS-sedimentation value. As N fertilize in 10 DAH, hardness of noodle was increased and chewiness of noodle was decreased