• The Korean Journal of Ecology
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• v.10 no.4
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• pp.175-182
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• 1987

Soybeans(Glycine max Merr. cv. Kwanggyo), inoculated with Rhizobium japonicum 110 and then sand-cultured with nitrate gradients (0, 1, 3, 10 and 30mM KNO3). were studied on the growth analysis, nitrogen fixation and nitrogen economy during the growing period. The maxium values of total leaf area, biomass and nitrogen quantity were increased 139%, 122% and 161%, respectively with higher concentration of nitrate treatment. Nodulation showed significant linear correlation with leaf area growth for each treatment of nitrate concentration increased. The more nitrate concentration increased, the more distribution ratios of dry matter and nitrogen to nodule decreased, and the more T/R ratios, CGR and N content increased. On the other hand, F/C ratios and RGR showed little changes. The amounts of nitrogen fixation of soybean alloted to 0, 1, 3, 10 and 30mM nitrate treatments were 100, 46, 14, 0.1 and 0.004% for the total nitrogen assimilation, respectively. The nitrogen utility of soybean plant was smaller than that of other plants and ranged from 23 to 30 at varying nitrate gradients.

• Journal of Wellbeing Management and Applied Psychology
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• v.6 no.3
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• pp.33-36
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• 2023

Purpose: Since the food wastewater contains a high concentration of nitrogen, it is very important to find a way to efficiently remove it. Research design, data and methodology: A total of four experiments were conducted under different conditions to remove ammonia nitrogen present in the food wastewater. The experiment was designed by adding sodium hypochlorite to the raw food wastewater and varying conditions such as pH control, aeration/precipitation, and stirring. Results: The ammonia nitrogen removal rate in Experiment 1 was about 12% (sodium hypochlorite added), ammonia nitrogen increased about 4.7% in Experiment 2 (sodium hypochlorite added after aeration/precipitation in a bioreaction tank, stirring), and decreased about 52.5% (sodium hypochlorite added after controlling and stirring). Conclusions: When the concentration of sodium hypochlorite was high, ammonia nitrogen was best removed, and the pH was adjusted to 12, and sodium hypochlorite was added after stirring, and the removal was the second best. If the method of this study is further studied and developed, it can be basic data for ammonia nitrogen removal in the future.

• Journal of Power System Engineering
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• v.11 no.4
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• pp.26-31
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• 2007

Recently, study on the improvement of combustion performance for the diesel engine by using the impinging spray in the combustion chamber has been actively studied. The purpose of this study is to examine the variation of exhaust emission between the trial engine with impinging plate and the prototype engine in accordance with change of fuel injection timing and fuel injection pressure. The concentration of nitrogen oxide of trial engine decreased more than 50% compared to prototype engine. However, smoke of trial engine indicated very high concentration compared to prototype engine. The effect of fuel injection timing on the nitrogen oxide and smoke indicated different results, that is, the concentration of nitrogen oxide decreased as the degree of fuel injection start become slower, whereas the concentration of smoke decreased as the degree of fuel injection start become faster.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.6
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• pp.586-591
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• 2004

We studied the dependence of hot-tarrier-induced degradation characteristics on nitrogen concentration in NO(Nitrided-Oxide) gate of nMOS, under ac and dc stresses. The $\Delta$V$_{t}$ and $\Delta$G$_{m}$ dependence of nitrogen concentration were observed, We observed that device degradation was suppressed significantly when the nitrogen concentration in the gate was increased. Compared to $N_2$O oxynitride, NO oxynitride gate devices show a smaller sensitivity to ac stress frequency. Results suggest that the improved at-hot carrier immunity of the device with NO gate may be due to the significantly suppressed interface state generation and neutral trap generation during stress.ess.

• KSBB Journal
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• v.25 no.6
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• pp.553-558
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• 2010

Increasing demands on fossil fuel have led to the unprecedented attraction to microalgal biofuel as an alternative energy. In this study, we investigated growth and lipid productions of microalga Nannochloris oculata under various carbon dioxide or nitrogen source concentrations and irradiance conditions. Biomass production of N. oculata was highest under 2% $CO_2$ with 0.3 flow rate (vvm). In addition, biomass productivities were proportional to the concentration of nitrogen source, whereas lipid biosynthesis was suppressed under higher nitrogen concentration (up to 50 mg/L). High irradiation ($160{\sim}180\;{\mu}mol/m^2{\cdot}s$) enhanced growth rate and lipid production of N. oculata.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.4
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• pp.277-289
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• 2003

This study proposes a mathematical model to characterize the removal of nitrogen oxides in a dielectric barrier discharge plasma process. As well as the reactions between nitrogen oxides, water vapor, oxygen and nitrogen, the model takes into account the effect of ethylene often used as a chemical additive to reduce the power consumption of the process on the removal of nitrogen oxides. Since the concentrations of the radicals concerned in the main reactions including O, OH, H and N should be calculated to predict the removal efficiency of nitrogen oxides, they were theoretically derived. The parameters affecting the removal of nitrogen oxides, such as initial concentration, discharge power, humidity, and ethylene concentration were experimentally evaluated, which were compared with the calculated results to verify the validity of the model proposed. The predicted concentrations of several byproducts formed in this process were also presented and discussed. The effects of several parameters mentioned above on the removal of nitrogen oxides were reasonable described by the proposed model.

• Journal of Power System Engineering
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• v.19 no.4
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• pp.82-88
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• 2015

The purpose of this study is to investigate the effect of the impinging plate on combustion process in Diesel engine. Especially, the variation of exhaust emission and engine performance by the change of fuel injection timing and fuel injection pressure between the trial engine with impinging plate and the prototype engine were examined. The nitrogen oxide concentration of the trial engine decreased more than 50% compared to the prototype engine, however, smoke concentration of the trial engine indicated higher degree than the prototype engine. The smoke concentration, fuel consumption rate and exhaust gas temperature decreased as the fuel injection timing become faster, whereas the nitrogen oxide concentration decreased as the fuel injection timing is retarded. The nitrogen oxide concentration, fuel consumption rate and exhaust gas temperature decreased as the fuel injection pressure become lower. But smoke concentration decreased as the fuel injection pressure become higher.

• Journal of Environmental Science International
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• v.19 no.4
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• pp.483-490
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• 2010

The purpose of this study is to investigate the effect of influent phosphorus concentration on the nitrogen and phosphorus removal in sequencing batch reactor(SBR) and sequencing batch biofilm reactors(SBBRs) in order to recover the enhanced biological phosphorus removal (EBPR) capacity at the sludge of the deterioration of EBPR capacity. In SBBRs, comparing to SBR, the organic removal was occurred actively at the 1 st non-aeration period because of the active phosphorus release at this period. However, the variation of TOC removal according to the decrease of influent phosphorus concentration was not clearly shown both in SBR and SBBRs. In case of SBR losing EBPR capacity, the EBPR capacity was not recovered by the decrease of the influent phosphorus concentration from 7.5 mg/L to 0.9 mg/L. The nitrogen removal increased by the decrease of influent phosphorus concentration both in SBR and SBBRs.

• Journal of Ginseng Research
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• v.24 no.2
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• pp.58-63
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• 2000

To develop the production of ginseng root using plant tissue culture technology, submerged culture conditions were optimized by means of the fractional factorial design with 4 factors and 3 levels by a RSM computer program. The ginseng (Panax ginseng C. A. Meyer) roots induced by plant growth regulators were cultured on SH medium and the effects of various pH of medium, sucrose concentration, nitrogen concentration and phosphate concentration on fresh weight of the ginseng root were investigated. The fresh weight of ginseng root increased with a decrease in nitrogen concentration and fresh weight of ginseng root varied from 1.00 to 2.33g under various conditions. The optimum pH of medium and sucrose concentration determined by a partial differentiation of the model equation, nitrogen and phosphate concentration were pH 5.6, sucrose 3.8%, nitrogen 50 mg/L and phosphate 80.7 mg/L, respectively. Under these conditions, the predicted growth of ginseng root was estimated to be 2.36g.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.1
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• pp.1-7
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• 2013

This study was to examine growth, carbon and nitrogen responses in foliage following forest fertilization in a red pine stand. Two types of fertilizer (N:P:K=113:150:37 kg $ha^{-1}$; P:K=150:37 kg $ha^{-1}$) were applied on late April 2011. Growth, carbon and nitrogen responses of foliage were monitored 3 times (July, September, November) after fertilization. Morphological growth responses (dry mass, leaf area, specific leaf area) with foliage age were not significantly (P > 0.05) affected by fertilizer application, while needle dry mass and leaf area of July were significantly lower in current-year-old than in one-year-old or two-year-old needles of September or November. Carbon concentration and content in foliage was little affected by fertilizer application compared with sampling month or needle age, while the NPK fertilizer produced high nitrogen concentration and content of foliage. The results indicate that nitrogen concentration and content in foliage may serve as an indicator of the nitrogen status by fertilization in a red pine stand.