• Journal of Fisheries and Marine Sciences Education
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• v.24 no.6
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• pp.755-762
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• 2012

Qualities properties of fish sauce made jack mackerel (Trachurns japonicus) at different salt concentrations (25~35%) for 240 days at fermentation temperature ($25{\sim}55^{\circ}C$) were investigated. Total nitrogen content of the fish sauce made jack mackerel at 25% salt concentration after 240 day of fermentation was higher than those of 30%, 35% salt concentration. Total nitrogen content was increased under the same condition as fermentation temperature increased except at $55^{\circ}C$. Amino nitrogen contents at 25% salt concentration after 240 day of fermentation at 35, 45, $55^{\circ}C$ were 949.3, 812.8 and 834.4 mg/100 g, respectively. Those at 25, $55^{\circ}C$ fermentation temperature were 811.2 and 614.8 mg/100 g, respectively. The amino acid nitrogen content at 30 and 35% salt concentration ware lower than 20% salt concentration and that after 240 day of fermentation at $55^{\circ}C$ was lowest. The volatile basic nitrogen content increased during fermentation as fermentation temperature increased. However, increasing salt concentration controlled the formation of volatile basic nitrogen. Histamine content of samples fermented at $25{\sim}55^{\circ}C$ after 240 days were 9~20 mg/kg showing that it was not significantly different among salt concentration. The results indicated that the controlled salt concentration and fermentation temperature could be used as a successful process for fish sauce of jack mackerel as an unused resource.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.586-589
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• 2002

The Ultra Violet(UV) emission characteristics of Neon + Nitrogen gas-mixture discharge was investigated in AC plasma display panel. The firing voltage of Ne+$N_2$ gas-mixture discharge increased with increasing nitrogen concentration. The UV intensity emitted from the gas discharge also increased with increasing nitrogen concentration. The UV efficiency increase with increasing $N_2$ partial pressure at low $N_2$ concentration, and then UV efficiency is saturated at high $N_2$ concentration.

• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1073-1080
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• 2011

In order to investigate and generalize the effects of carbon and nitrogen sources on the growth of and lipid production in Chlorella sp. 227, several nutritional combinations consisting of different carbon and nitrogen sources and concentrations were given to the media for cultivation of Chlorella sp. 227, respectively. The growth rate and lipid content were affected largely by concentration rather than by sources. The maximum specific growth was negatively affected by low concentrations of carbon and nitrogen. There is a maximum allowable inorganic carbon concentration (less than 500~1,000 mM bicarbonate) in autotrophic culture, but the maximum lipid content per gram dry cell weight (g DCW) was little affected by the concentration of inorganic carbon within the concentration. The lipid content per g DCW was increased when the microalga was cultured with the addition of glucose and bicarbonate (mixotrophic) at a fixed nitrogen concentration and with the lowest nitrogen concentration (0.2 mM), relatively. Considering that lipid contents per g DCW increased in those conditions, it suggests that a high ratio of carbon to nitrogen in culture media promotes lipid accumulation in the cells. Interestingly, a significant increase of the oleic acid amount to total fatty acids was observed in those conditions. These results showed the possibility to induce lipid production of high quality and content per g DCW by modifying the cultivation conditions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.3
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• pp.207-214
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• 2009

Crossover of nitrogen from cathode to anode is inevitable in typical membranes used in PEM fuel cells. This crossovered nitrogen normally accumulates in the hydrogen recirculation system at anode side channels. Excessive buildup of nitrogen in the anode side lowers the relative hydrogen concentration and finally affects the performance of fuel cell stack. So it is very important to analysis the nitrogen gas crossover at various operating conditions. In this study, characterization of nitrogen gas crossover in PEM fuel cell stack was investigated. The mass spectroscopy (MS) has been applied to measure the amount of the crossovered nitrogen gas at the anode exit. Results show that nitrogen gas crossover rate was affected by current density, anode and cathode stoichiometric ratio and operating pressure. Current density, anode stoichiometric ratio and anode operating pressure do not affect nitrogen crossover rate but anode exit concentration of nitrogen. Cathode pressure and stoichiometric ratio largely affect the nitrogen crossover rate.

• Journal of the Korean institute of surface engineering
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• v.29 no.5
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• pp.549-555
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• 1996

Diamond Like Carbon film is amorphous film which is considered to consist of three coordinate graphite structure and tetrahedron coordinate diamond structure. Its hardness, thermal conductivity and chemical stability are nearly to one of diamond. It is well known to become semi-conductor by doping of inpurity. In this study Diamond Like Carbon film was synthesized by Microwave Plasma CVD in the gas mixture of hydrogen-methan-nitrogen and doped of nitrogen on the single-crystal silicon or silica glass. The temperature of substrate and nitrogen concentration in the gas mixture had an effect on the bonding state, structural properties and conduction mechanism. The surface morphology was observed by Scanning Electron Microscope. The strucure was analyzed by laser Raman spectrometry. The bonding state was evaluated by electron spectroscopy. Diamond Like Carbon film synthesized was amorphous carbon containing the $sp^2$ and $sp^3$ carbon cluster. The number of $sp^2$ bonding increased as nitrogen concentration increased from 0 to 40 vol% in the feed gas at 1233K substrate temperature and at $7.4\times10^3$ Pa. Increase of nitrogen concentration made Diamond Like Carbon to be amorphous and the doze of nitragen could be controlled by nitrogen concentration of feed gas.

• Journal of environmental and Sanitary engineering
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• v.23 no.2
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• pp.19-25
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• 2008

For measurement of tylosin, ammonia nitrogen, and glucose concentration during the culture of Streptomyces fradiae using Near Infrared Spectroscopy, the calibration using various mathematical models was performed and then, based on the linear model, the validation was carried out. In the case of sucrose concentration using the MLR method, the Standard Error of Prediction and Multiple correlation coefficient were 1.97, and 0.991, respectively. In the case of ammonia nitrogen concentration using the PLSR method, the Standard Error of Prediction and Multiple correlation coefficient were 0.13, and 0.990, respectively. In the case of tylosin concentration using the PLSR method, the standard Error of Prediction and Multiple correlation coefficient were 0.54, and 0.984, respectively.

• Journal of Nutrition and Health
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• v.30 no.6
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• pp.715-726
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• 1997

This study was conducted longitudinally following the total nitrogen , total lipid, and lactose concentrations and their factors on concentrations of energy-yielding nutrients in human milk from 2-5 days to 12 weeks postpartum of 45 lactating Korean mothers. All samples were from well-defined subjects. And uniform collection procedures were used . Total nitrogen concentration of milk decreased significantly from 385mg/이 at 2-5 days to 201mg/dl at 12 weeks postpartum. Total lipid concentration increased from 1.98g/dl at 2-5 days to 3.09g/dl at 12 weeks postpartum. However, there was a large variation in the concentration of total lipids. Lactose concentration increased signifciantly from 6.53g/dl at 2-5 days to 7.48g/dl at 12 weeks. Total nitrogen concentration in milk was positively related to pregnancy weight gains at 2 and 6 weeks postpartum. Total lipid concentration was positively related to infant birth weight : however, it was negatively related to the maternal weight loss. In addition, total lipid concentration was positively related to parity and maternal percentage body fat at 12 weeks postpartum. Milk lactose concentration was positively related to parity at 2 weeks postpartum.

• Journal of Korean Society on Water Environment
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• v.28 no.1
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• pp.94-101
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• 2012

The performance data for eight years from a free-surface-flow constructed wetland system receiving agricultural tailwater were used to analyze denitrification rate and nitrogen treatment characteristics according to season and wetland design. Seasonal difference between growing season (March~November) and winter season (December~February) was shown in the concentration of all nitrogen species. Seasonal nitrogen treatment has similar trend with temperature and measured denitrification rate. The highest denitrification rate was measured in July, but treatment efficiency was most higher in May and June. Nitrogen absorption of vegetation could affect to these wetland performances, therefore dense population of wetland vegetation might be helpful. According to design of wetland, at least 25~50 m of wetland length was needed to decrease effluent T-N concentration to background concentration in growing season. In winter season, wetland needed much longer distance to reduce T-N concentration. Mass removal rate was continuously high through whole year because runoff coefficient was low in winter season. Applicability of constructed wetland was observed for the total maximum daily load that control T-N load.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.3
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• pp.146-152
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• 1987

Sorghum cv. Pioneer 93 1, sorghum-sudangrass hybrid cv. Sioux and maize plant cv. Blizzard were assayed for toxic concentrations of nitrate-nitrogen ($NO_3$-N) and their relationship to morphological characteristics and environmental temperature in a field and phytotron trial. In the phytotron, sorghum and maize plants ranging from emergence to heading stage, were grown under different day/night temperatures of 30125, 25/20,28/18 and 1818 degree C. Nitrate-nitrogen in sorghum and maize plants was accumulated mainly in stems. Therefore nitrate concentration in the young plants was increased as development of stalks advanced and was highest at the stage of 3-4 leaves, when the plants had a leaf weight ratio 0.78-0.80 g/g plant weight. However, nitrate concentrations of the plant decreased as morphological development progressed, especially from the stage of growing point differentiation. Correlation coefficients showed a positive correlation of nitrate concentration with leaf weight ratio, leaf area ratio and specific leaf area, while plant height, dry matter percentage and absolute growth rate showed a negative association with TEX>$NO_3$-N ($P{\le}0.1$%). Cyanogenic glycosides, total nitrogen and crude protein were close associated with nitrate accumulation, and positively significant ($P{\le}0.1$%). High temperature over 30/25^{\circ}C.$ for 3 weeks increased N-uptake and dry matter accumulation, but reduced nitrate concentration. Under cold temperature below 18/8^{\circ}C.$ concentration of nitrate-N was increased in spite of its limited nitrogen uptake and plant growth.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.3
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• pp.325-329
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• 2013

A result of estimating the effects of initial phosphorus concentration and nitrogen sources on removal of nitrogen and phosphorus in wastewater treatment using Scenedesmus dimorphus shows that there was no difference in microalgae growth amount and nitrogen removal amount by phosphorus concentration(5 ~ 60 mg/L). On the other hand, as initial phosphorus concentration increased, phosphorus removal amount was increased by luxury uptake of microalgae. Scenedesmus dimorphus preferred to ammonia when ammonia(40 mg/L) and nitrate(40 mg/L) are simultaneously presented and nitrogen removal rate of ammonia was high at approximately 20 mg/L/day.