• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.219-223
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• 1982

The results of study on the yield and absorption of N and K applied to the chinese cabbage (Brassica pekinensis) which was grown at comparatively infertile red-yellow soil in the fall of 1980 are summerized as below. 1. The optimum quantities of potash to be applied for the autumn chinese cabbage is suggested in the range of 15kg-20kg/10a, $K_2O$. 2. Combined treatments of N and K showed a positive interaction by promoting the effect of the other element. The increase of Nitrogen absorption from the additionally applied 10kgs of nitrogen on top of 15kg N/10a showed only 16 per cent at potash minus plot, while that of potash applied plot showed 60 per cent. The cabbage yield increase therefor, at high rate of nitrogen only was 1,700kgs per 10 are over low rate of nitrogen, while high nitrogen plus potash treatment produced additional 2,200kgs over the low rates of N and K. 3. Additional 10kgs of nitrogen applied on top of 15kgs N/10a resulted in increasing soil potassium uptake; 4kgs of soil potassium was additionally absorbed at potash applied plot and 6.5kgs at potash minus plot. 4. Utilization of applied potash was greater at low rates of N, and K application (each 15kgs of N and $K_2O$ per 10a) where 77 per cent of applied potash was utilized, while high rates of N and K application (each 25kgs of N and $K_2O$ per 10a) showed 44 per cent of potash utilization rate. Lower utilization of applied potash at high rate of nitrogen application is due probably to greater uptake of soil potassium. 5. N and K contents in the chinese cabbage are 0.17-0.20% and 0.35-0.43% respectively and these were not statistically correlated with the yields.

• Journal of Welding and Joining
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• v.18 no.1
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• pp.59-69
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• 2000

The purpose of the present study was to investigate weld metallurgical phenomena such as primary solidification mode, microstructural evolution and hot cracking susceptibility in nitrogen-bearing austenitic stainless steel GTA welds. Eight experimental heats varying nitrogen content from 0.007 to 0.23 wt.% were used in this study. Autogenous GTA welding was performed on weld coupons and the primary solidification mode and their microstructural characteristics were investigated from the fusion welds. Varestraint test was employed to evaluate the solidification cracking susceptibility of the heats and TCL(Total Crack Length) was used as cracking susceptibility index. The solidification mode shifted from primary ferrite to primary austenite with an increase in nitrogen content. Retained delta ferrite exhibited a variety of morphology as nitrogen content varied. The weld fusion zone exhibited duplex structure(austenite+ferrite) at nitrogen contents less than 0.10 wt.% but fully austenitic structure at nitrogen contents more than 0.20 wt.%. The weld fusion zone in alloys with about 0.15 wt.% nitrogen experienced primary austenite + primary ferrite solidification (mode AF) and contained delta ferrite less than 1% at room temperature. Regarding to solidification cracking susceptibility, the welds with fully austenitic structure exhibited high cracking susceptibility while those with duplex structure low susceptibility. The cracking susceptibility increased slowly with an increase in nitrogen content up to 0.20 wt.% but sharply as nitrogen content exceeded 0.20 wt.%, which was attributed to solidification mode shift fro primary ferrite to primary austenite single phase solidification.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.6
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• pp.831-836
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• 2006

This study compared the effects of two levels of crude protein (CP) supplementation during a close-up dry period on the productive performance, nitrogen balance, and blood profiles of Holstein cows. Eighteen cows (8 primigravid and 10 multiparous), 21 days prior to calving, were divided into four groups and fed a diet containing a low (11.5 to 12.7% CP) or high (14.1 to 15.3% CP) level of protein. Following parturition, all cows were offered the same diet. Nitrogen balance was measured 12 d to 10 d prior to the expected calving date. Whole feces and urine were collected. The higher close-up CP did not improve milk production during the early lactation period (14 w) in multiparous cows but tended to increase production by 2 kg of milk per day in primigravid cows. There were no differences in the weight of calves, the weight of the placenta, or the incidence of calving difficulty. Nitrogen intake, urine nitrogen and nitrogen retention were increased by the higher CP diet in primigravid and multiparous cows. All groups of cows showed a positive nitrogen balance. In particular, higher nitrogen retention was observed in primigravid cows fed the higher CP diet. With the exception of plasma urea nitrogen (PUN), non of the blood profiles were influenced by the CP level. The higher close-up CP increased the PUN during the period studied in primigravid and multiparous cows. These results indicate that a CP level of 14% during a close-up dry period is optimal for primigravid cows, and 12% CP level is sufficient for multiparous cows.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.44-49
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• 2015

Urea has been the most useful N-source, due to lower cost per unit of N. But nitrogen use efficiency of urea may be reduced because of losses from agricultural system by volatilization of ammonia to atmosphere. This study was conducted to evaluate the nitrogen efficiency and growth of hot pepper (Capsicum annuum L.) by mixed treatment with nitrogen and zeolite. They were treated with N $161kg\;ha^{-1}$, N $230kg\;ha^{-1}$, nitrogenzeolite mixture (NZM) $161kg\;ha^{-1}$, NZM $230kg\;ha^{-1}$ and N $0kg\;ha^{-1}$, respectively. In the soil chemical properties after experiment, soil pH decreased but available $P_2O_5$, EC and total nitrogen increased in nitrogen-zeolite mixture treatment. $NO_3-N$ content in the soil showed the highest level in NZM $230kg\;ha^{-1}$. NZM $161kg\;ha^{-1}$ treatment increased growth and yield of hot pepper compared to urea alone. Nitrogen utilization efficiency of hot pepper plant was 47.15% at the treatment of NZM $161kg\;ha^{-1}$, while 36.74% at N $230kg\;ha^{-1}$. These results showed that application of mixture of nitrogen and zeolite had positive influence to improve the efficiency of nitrogen utilization and increase of red pepper yield.

• Analytical Science and Technology
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• v.15 no.1
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• pp.91-95
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• 2002

Carbon paste electrodes, modified with 5,6,14,15-dibenzo-1,4-dioxa-8,12-diazacyclopentadeca-5,14-diene containing different ligating atoms of oxygen and nitrogen, have been employed for the voltammetric determination of Ag(I) ion from aqueous solution. The voltammetric response was characterized with respect to paste composition, preconcentration method, kind of anion, variation of pH, Ag(I) ion concentration, and possible interferences. Linear calibration curves were obtained for Ag(I) ion concentration ranging from $3.0{\times}10^{-6}M$ to $8.0{\times}10^{-5}M$, and detection limit was $8.5{\times}10^{-7}M$.

• The Korean Journal of Food And Nutrition
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• v.11 no.6
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• pp.640-646
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• 1998

For the production of nonprotein $\alpha$-glucosidase inhibitor from the Streptomyces sp. NS15 strain, effects of initial optimum pH, nitrogen sources, carbon sources, cationic metal ions, agitation speed and aeration rate were investigated. Initial optimum pH of medium was 7.0. The most effective nitrogen and carbon sources were soybean meal 2.0%(w/v) and glucose 1.6%(w/v), respectively. The cationic metal ins had no stimulating effect on inhibitory activity of $\alpha$-glucosidase except Fe2+. Agitation speed and aeration rate were effective at 400rpm and 1vvm, respectively. In the jar-fermenter cultivation for 4 days under optimal culture conditions, the culture broth showed the inhibitory acitivity of 3,200units/ml, which is 25 times higher than that of basic medium (CYM) for porcine intestinal $\alpha$-glucosidase. The inhibitory activity of $\alpha$-glucosidase reached about 3,200units/ml after 4 days of cultivation and decreased gradually for a further two days.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.1
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• pp.89-96
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• 1998

The experiment was conducted with 120 barrows weaned at 21 days of age to estimate their lysine requirement weaned at 21 days of age when other important amino acids were fortified to get optimal ratio to lysine. The treatments were 1.15% (control), 1.25%, 1.35%, 1.45%, 1.55%, 1.65% total lysine in the diet. Based on the growth performance total lysine requirement of 21-day old pigs appears to be 1.45%. The lowest digestibilities of dry matter and crude fat were found in pigs fed 1.15% total lysine diet and the highest were found in pigs fed 1.65% total lysine diet with no significant differences among treatments. Nitrogen digestibility increased as the total lysine level increased up to 1.35% (p < 0.05) and remained relatively constant beyond 1.35%. However, the best nitrogen digestibility was observed in pigs fed 1.45% total dietary lysine. Gross energy, crude ash and phosphorus digestibilities did not differ due to the increase in total lysine level. The amounts of excreted dry matter and nitrogen differed significantly by the increase in lysine level up to 1.35% (p < 0.05), while phosphorus excretion was not influenced by the lysine level. Dry matter and nitrogen excretion were reduced by 13.6% and 18.4%, respectively, when 1.45% lysine was offered to the pigs compared to the those fed on 1.15% lysine diet. The amino acid digestibilities increased as the total lysine level increased up to 1.45% (p < 0.05), and remained constant beyond 1.45%. The lysine requirement for the pigs weighing 6 to 14 kg seems to be higher than the previous estimates and in order to reduce pollutant excretion the accurate nutrient requirement should be set and applied to the animal.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.393-399
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• 2013

The effect of solution temperature and nitrogen form on cucumber (Cucumis sativus L.) growth, photosynthesis and nitrogen metabolism was investigated in hydroponic culture. Cucumber plants were grown for 35 days in a greenhouse at three constant solution temperatures ($15^{\circ}C$, $20^{\circ}C$, and $25^{\circ}C$) within a natural aerial temperature ($15-30^{\circ}C$). Four nitrate:ammonium ($NO{_3}^-:NH{_4}^+$) ratios (10:0, 8:2, 5:5, and 2:8 $mmol{\cdot}L^{-1}$) at constant nitrogen (N) concentration of $10mmol{\cdot}L^{-1}$ were applied within each solution temperature treatment. Results showed an increasing solution temperature enhanced plant growth (height, dry weight, and leaf area) in most N treatments. Dry weight accumulation was greatest at the 10:0 $NO{_3}^-:NH{_4}^+$ ratio in the $15^{\circ}C$ solution, the 5:5 ratio in the $20^{\circ}C$ solution and the 8:2 ratio in the $25^{\circ}C$ solution. Photosynthetic rate (Pn) response to solution temperature and $NO{_3}^-:NH{_4}^+$ ratio was similar to that of plant growth. Probably, the photosynthate shortage played a role in the reduced biomass formation. Increasing solution temperature enhanced the nitrate reductase (NR) activity, and further reduced shoots nitrate content. Our results indicate that the optimal ratio of nitrate to ammonium that promotes growth in hydroponic cucumber varies with solution temperature.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.6
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• pp.75-86
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• 2010

This study used a phytosociolocal approach in classifying the vegetation communities of evergreen broad-leaved forest in Gageodo island of Korea, and the results are as follows: Quercus acuta community was classified into Dendropanax morbifer subcommunity, Daphniphyllum macropodum subcommunity, and Quercus acuta typical subcommunity. In the study sites, soil organic matter, total nitrogen, available phosphorous, exchangeable K, exchangeable Ca, exchangeable Mg, cation exchange capacity, and soil pH were ranged from 15.23~18.89%, 0.73~0.99%, 4.31~15.06 (mg/kg), 1.09~1.13 ($cmol^+$/kg), 21~7.15 ($cmol^+$/kg), 1.33~2.10 ($cmol^+$/kg), 33.04~38.28 ($cmol^+$/kg) and 4.47~4.83 respectively. The Dendropanax morbifer subcommunity were found in sites with high percentage of organic matter, total nitrogen, and low percentage of exchangeable Mg and Ca while the Daphniphyllum macropodum subcommunity were found in sites with low percentage of organic matter, total nitrogen, exchangeable Mg and Ca. The Quercus acuta typical subcommunity were found in sites with high percentage of organic matter, total nitrogen, exchangeable Mg and Ca. It is urgently needed to work for the preparation of an island management plan to the levels of species through habitat conservation.

• Journal of Korean Society on Water Environment
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• v.23 no.2
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• pp.206-215
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• 2007

The objective of this study was to establish the optimal system operating strategies for nitrogen and phosphorus removal through model simulation system built for advanced wastewater treatment targeting on simultaneous temporal/special phase isolation BNR process. The simulation system was built with unit process modules using object modules in GPS-X code. The system was well verified by field experiment data. Simulation study was carried out to investigate performance response to design and operation parameters, i.e. hydraulic retention time (HRT), solids retention time (SRT), and cycle time. The process operated at HRTs of 10~15 hours, longer SRTs, and cycle time of 2 hours showed optimal removal of nitrogen. The HRTs of 10~15 hours, SRTs of 20~25 days, and longer cycle time was optimal for phosphorus removal. Both simulation and field studies showed that optimal operating strategies satisfying both the best nitrogen and phosphorus removals include HRTs ranged 10~15 hours, SRTs ranged 20~25 days, and cycle times of 4~8 hours. The simulation system with modularization of generalized components in BNR processes was, therefore, believed to be a powerful tool for establishing optimal strategies of advanced wastewater treatment.