• Korean Journal of Environmental Agriculture
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• v.38 no.3
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• pp.124-132
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• 2019

BACKGROUND: Silver grass (Miscanthus sinensis) No. 1 was developed for production of bio-ethanol, and for the purpose the silver grass growing sector was established in Geumgang basin, Iksan, Jeonbuk, in 2011. However, the other application potentials except for using as the bio-energy resources should be considered because of the drop in international oil prices. Therefore, there is the necessity of a scientific basis to use the silver grass instead of rice straw as the organic matter source that is used for improvement of soil quality in the plastic film house. METHODS AND RESULTS: The silver grass was applied at 5, 10, 15 and 20 Mg/ha and tilled before the watermelon was planted in the plastic film-house. The control plot was treated with 10 Mg/ha with rice straw, and watermelons have been cultivated for 3 years(2017~2019). Soil aggregation, soil chemistry, and the growth characteristics were investigated, when the watermelon was harvested every year. Soil aggregation levels at the 2nd and 3rd year of watermelon harvest were similar from the plot applied with the silver grass at 5 Mg/ha and the control plot, and increased in the silver grass treated plots with more than 10 Mg/ha. However, there was no statistically significant difference between the plots. The nitrogen mineralization of silver grass in the control plot tended to be similar to the 5 Mg/ha plot, but the silver grass treated plots with over 10 Mg/ha showed low nitrogen mineralization. Soil EC on harvest stage was proportional to the applied mass of the silver grass, but pH was in inverse with the applied mass. Soil organic matter content, available phosphate, and exchangeable cations increased with the continued use of silver grass. Watermelon weight found to be the best on more than 15 Mg/ha of silver grass, and the sugar content was highest when 10 Mg/ha was treated. CONCLUSION: The use of the silver grass at 10 Mg/ha annually as the organic source was effective in replacing rice straw while growing fruits and vegetables on the plastic film house.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.40-46
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• 2008

This paper presents the optimal motion control for 3-axis SCARA robot by using $LabVIEW^{(R)}$. Specifically, for optimal motion control of 3-axis SCARA robot, we study velocity profile based on finite jerk(the first derivative of acceleration) and optimal gain tunig based on frequency response method by using $LabVIEW^{(R)}$. The velocity optimization with finite jerk aims at generating the smooth velocity profile of robot. Velocity profile based on finite jerk is acquired and applied to 3-axis SCARA robot by using $LabVIEW^{(R)}$. DSA(Dynamic Signal Analyzer) for frequency response method is programed by using $LabVIEW^{(R)}$. We obtain the bode plot of transfer function about 3-axis SCARA robot by using DSA, and perform the gain tuning considering dynamic characteristic based on the bode plot. These experiments have shown that the proposed motion control can reduce vibration displacement and response error rate each 33.7% and 51.7% of 3-axis SCARA robot.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.1
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• pp.14-19
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• 2000

In order to develop an appropriate cultural practice for a newly bred 2-rowed, waxy, naked barley cultivar 'Duwonchapssalbori' in the southern region, 2 varieties, 3 seeding dates, 4 seeding rates were designed with 2 replications. The heading and maturity dates of 'Duwonchapssalbori' were' earlier than 'Saessalbori by 2-5 and 4 days, respectively. Culm length of 'Duwonchapssalbori' was 60 to 66cm with lodging resistance. Grain yields of both varieties were 4.28-4.33 ton/ha in the plot of Oct. 20 seeding, 4.11-4.18 ton in the plot of Oct. 28 seeding, and 3.7-13.89 ton/ha in the Nov. 5 seeding. Grain yield with different seeding rates highly significantly fitted with secondary polynomial equations in the plots of Oct. 20 and Oct. 28 seedings ($R^2$=0.84-0.85), showing the greatest yield with seeding rate of 140kg per ha. However, the grain yield with various seeding rates in the plot of Nov. 5 seeding showed simple linear regression ($R^2$=0.71), showing the seeding rate over 160kg in the case of later seeding to be optimal. Number of spikes per $m^2$ significantly contributed to grain yield, and fitted to simple linear regression ($R^2$=0.881-0.891), suggesting that plenty of early stands should be established at early seedling stage for high grain yield. Young spikes of 'Duwonchapssalbori' in the plot of Oct. 20 seeding elongated with linear increments since Feb. 10 (6.7mm), and showed rapid increment since March 7 (15.1mm). However, elongation of young spikes of 'Saessalbori' began from March 15 with slow increments. From these studies, the optimum seeding date and seeding rate in 'Duwonchapssalbori' were Oct. 20-28 and 140kg per ha for high grain yield in the southern regions.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.130-138
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• 1995

Machined graphite/epoxy surfaces were studied by using SEM (Scanning Electron Microscopy), surface profilometry and its analysis to determine suitable surface describing parameters for machined unidirectional and multidirectional laminate composite. The surface roughness and profile are found to be highly depdndent on the fiber layup direction and the measurement direction. It was possible to machine 90 .deg. and -45 .deg. plies due to the adjacent plies, which were holding those plies. It was found that the microgeometrical variations in terms of roughness parameters $R_{a}$ without $D_{y}$(Maximum Damage Depth) region and $D_{y}$are better descriptors of the machined laminate composite surface than commonly used roughness parameters $R_{a}$and $R_{max}$ The characteristics of surface profiles in laminate composite are well represented in CPD (Cumulative Probability Distribution) plot and PPD (Percentage Probability Density) plot. Edge-trimmed multidirectional laminate surfaces are Gaussian and random for profiles measured along the tool movement direction, they are periodic and non-Gaussian in the direction perpendicular to the tool movement.t.ent.t.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.41-45
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• 1973

This study was carried out in the central part of Korea in 1972 to investigate optimum grain number per square meter and variation of the yield and its components in the direct sowing culture on irrigated paddy field. The results could be summarized as follows; 1. Number of maximum tillerings was directly increased with increase of grain number from 120 to 280 per square meter and it was gradually decreased with increase of number sowing grain. So number of maximum tillerings showed at the plot of 280 grain per square meter. Also it was showed remarkable competition at the plot more than 280 grain per square meter. 2. Percentage of effective tiller was decreased with increase of number of sowing grain from 120 to 280 per square meter and after it was gradually decreased with increase of number of sowing grain. 3. It was not remarkable competition in plot less than 1, 000 tillering per square meter on the number of maximum tillerings. 4. It was remarkable positive correlation between the number of panicle and the number of sowing grain, but it was tendency to negative correlation between the number of panicle and the number of spiklets per panicle, and between the number of panicle and the ripening ratio. 5. Correlation coefficient between the yield and the number of spiklet per square meter of land area was 0.929, r=0.695 in the yield and the number of panicle, r=0.796 in the number of panicles and the number of spiklets per square meter Also in rank correlation, it was showed most highly positive correlation(r=0.954) between the yield and the number of panicles, so number of panicles was most largely dominated on yield among the yield components in direct sowing culture on irrigated paddy field. 6. It was producted highest yield in the plot of 280 grain sowing per square meter.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.471-476
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• 2014

A kinetic study on aminolysis of 2-chloro-4-nitrophenyl X-substituted-benzoates (2a-k) in 80 mol % $H_2O/_20mol%$ DMSO at $25.0^{\circ}C$ is reported. The Br${\emptyset}$nsted-type plot for the reactions of 2-chloro-4-nitrophenyl benzoate (2g) with a series of cyclic secondary amines curves downward (e.g., ${\beta}_1=0.25$, ${\beta}_2=0.85$ and $pK_a^o=10.3$), which is typical of reactions reported to proceed through a stepwise mechanism with a change in ratedetermining step (RDS). The Hammett plot for the reactions of 2a-k with piperidine consists of two intersecting straight lines, while the corresponding Yukawa-Tsuno plot exhibits an excellent linear correlation with ${\rho}_X=1.15$ and r = 0.59. Thus, it has been concluded that the nonlinear Hammett plot is not due to a change in RDS but is caused by stabilization of substrates through resonance interactions between the electron-donating substituent and the C=O bond. Substrates possessing a substituent at the 2-position of the leaving aryloxide deviate negatively from the curved Br${\emptyset}$nsted-type plot for the reactions of Y-substituted-phenyl benzoates (3a-i), implying that the steric hindrance exerted by the substituent at the 2-position is an important factor which governs the reactivity of Y-substituted-phenyl benzoates.

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1128-1132
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• 2014

A kinetic study on aminolysis of 4-chloro-2-nitrophenyl X-substituted-benzoates (6a-i) in MeCN is reported. The Hammett plot for the reactions of 6a-i with piperidine consists of two intersecting straight lines, while the Yukawa-Tsuno plot exhibits an excellent linear correlation with ${\rho}_X$ = 1.03 and r = 0.78. The nonlinear Hammett plot is not due to a change in rate-determining step (RDS) but is caused by the resonance stabilization of substrates possessing an electron-donating group in the benzoyl moiety. The Br${\phi}$nsted-type plot for the reactions of 4-chloro-2-nitrophenyl benzoate (6e) with a series of cyclic secondary amines is linear with ${\beta}_{nuc}$ = 0.69, an upper limit for reactions reported to proceed through a concerted mechanism. The aminolysis of 6e in aqueous medium has previously been reported to proceed through a stepwise mechanism with a change in RDS on the basis of a curved Br${\phi}$nsted-type plot. It has been concluded that instability of the zwitterionic tetrahedral intermediate ($T^{\pm}$) in MeCN forces the reaction to proceed through a concerted mechanism. This is further supported by the kinetic result that the amines used in this study are less reactive in MeCN than in $H_2O$, although they are more basic in MeCN over 7 $pK_a$ units.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2455-2460
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• 2013

Second-order rate constants ($k_N$) have been measured spectrophotometrically for the nucleophilic displacement reactions of 4-nitrophenyl X-substituted-cinnamates (4a-4e) and Y-substituted-phenyl cinnamates (5a-5e) with Z-substituted-phenoxide anions in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. The Hammett plot for the reactions of 4a-4e with 4-chlorophenoxide (4-$ClPhO^-$) consists of two intersecting straight lines, which might be taken as a change in the rate-determining step (RDS). However, it has been concluded that the nonlinear Hammett plot is not due to a change in the RDS but is caused by stabilization of the ground state of substrates possessing an electron-withdrawing group in the cinnamoyl moiety through resonance interactions, since the Yukawa-Tsuno plot exhibits an excellent linear correlation with ${\rho}X=0.89$ and r = 0.58. The Br${\o}$nsted-type plot for the reactions of 4-nitrophenyl cinnamate (4c) with Z-substituted-phenoxides is linear with ${\beta}_{nuc}=0.76$. The Br${\o}$nsted-type plot for the reactions of Y-substituted-phenyl cinnamates (5a-5d) with 4-chlorophenoxides (4-$ClPhO^-$) is also linear with ${\beta}_{lg}=-0.72$. The Hammett plot correlated with ${\sigma}^-$ constants for the reactions of 5a-5d results in a much better linear correlation than that correlated with ${\sigma}^o$ constants, indicating that a partial negative charge develops on the O atom of the leaving aryloxide. Thus, the reactions have been concluded to proceed through a concerted mechanism.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.3
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• pp.256-260
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• 1995

This study was carried out to select economic-crops according to the improvement methods of newly-reclaimed soils. Silage corn, soybean, Job's tears and sweet potato were cultivated under 6 treatments including integrated improvement plot, control plot, compost plot, subsoiling plot, phosphate plot and lime plot on the Songjeong loam from 1985 to 1988. Crop yields and soil physical properties were investigated throughout the experiment. Soil porosity in the sweet potato plots were highest. In case of cultivated years, those of 4th year were lowest. Averaged yield increasing ratios of silage corn, soybean, job`s tears and sweet potato in the integrated improvement plots were 132%, 29%, 49% and 59%, respectively. And that of 5 soil improved treatments for 4 crops were 53%, 15%, 25% and 38%, respectively. After subtraction of the total expenses of soil conditioners, the economical efficiency of soil improvements were clear in the 4 crops except the compost plot of silage corn. That of sweet potato plot was the highest.

• The Korean Journal of Ecology
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• v.9 no.1
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• pp.91-101
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• 1986

To investigate the distribution of Plantago asiatica Linne, almost, restricted on the road-side, the plant growth analyzed by experimental cultivation under the condition of tread-pressure; 10 times/day (7.33kg/$cm^2$ ), 20 times/day (12.27kg/$cm^2$), 30 times/day (20.05kg/$cm^2$ ) and the control plot (1.68kg/$cm^2$ ). The matter production in the 10-time-per-diem plot (7.33kg/$cm^2$ ) of tread-pressure howed more large value than that inthe control one (1.68kg/$cm^2$ ) and those in the 20-0time-per-diem plot (12.27kg/$cm^2$ ) and the 30-time-per-diem one (20.05kg/$cm^2$ ) small values than that of the control plot. Especially, the growth of roots and spikes was extremely repressed. The number of leaves, scapes and lateral buds tend to increase in the tread-pressure of 20 times/day (12.27kg/$cm^2$ ) and 30 times/day (20.05kg/$cm^2$ ). The water contents of roots along the increase of tread-pressure to continuosly decreased. By the increase of tread-pressure, T/R ratio and C/F ratio their group decreased. The plant growth (7.33kg/$cm^2$ ) in the 10-time-per-diem plot increased more than that in the control one is regarded as the effect of tread-pressure affection on the road-side distribution of this plant.