• 한국작물학회지
• /
• 제47권4호
• /
• pp.323-327
• /
• 2002

Plant growth and the two components of respiration, growth and maintenance, were compared between low and high nitrogen applications in hydroponic culture on a high-yielding rice cultivar 'Takanari' (Oryza sativa L.). Grain yield decreased by high nitrogen application, and thus this cultivar has low adaptability to nitrogen. Growth efficiency (GE) and net assimilation rate (NAR) were lower in the high-nitrogen plot. The maintenance coefficient (m) and growth coefficient (g) of dark respiration were 0.0111 $d^{-1}$ and 0.196 in the low-nitrogen plot and 0.0166 $d^{-1}$ and 0.237 in the high-nitrogen plot, respectively. Thus, high nitrogen application increased both g and m. Calculated $R_m$ (maintenance respiration rate) was 70 and 90% of total respiration rate at heading, respectively. The significance of nitrogen adaptability and g was discussed.

• Journal of Nutrition and Health
• /
• 제21권1호
• /
• pp.47-60
• /
• 1988

This study was performed to investigate the effect of dietary levels on protein metabolism in eight healthy Korean adult females. The 20-day metabolic study consisted of 2 day adaptation period and three 6-day experimental. Three experimental diets were low protein (LP : protein 44g), high protein(HP : protein 85g) and high animal protein (HAP : protein-84g). The apparent absorption and balance on nitrogen were significantly higher in high protein than in low protein diet. Nitrogen, absorption rate was about 75% for low protein and about 85% for high protein intake. The mean values of nitrogen balance were -1.28% for low protein and 0.78% for high protein diet. All the subjects were in negative nitrogen balance at the low protein intake while they were in positive nitrogen balance at the high protein intake. The mean daily urinary nitrogen excretion increased with increased level of protein intake. Urea nitrogen was the largest part of the urinary nitrogen. The ratio of urea nitrogen to total urinary nitrogen increased significantly for 79 to 85% as protein intake was doubled.

• 한국연초학회지
• /
• 제12권2호
• /
• pp.91-101
• /
• 1990

A field experiment was conducted to find out the effects of field productivity, variety and nitrogen rate on the yield, quality, chemical constituents and physical properties of burley cured leaf in three field with different productivity(Degree of field productivity: A ; high, B ; medium, C : low) during successive two years(1988~89). The yield and quality were remarkably lowered when nitrogen fertilizer being applied much in low productive field. As compared with Burley 21, KB101 showed high yield, particularly the yield of KB101 in low productive field was relatively high. The effect of nitrogen rate on the yield was somewhat different according to field productivity and production year. When the nitrogen fertilizer being applied above 22.5kg/10a, the added nitrogen had no effect on the yield. Total nitrogen content of cured leaf grown in low productive field was high while total alkaloid was low, therefore total alkaloid/total nitrogen ratio was remarkably low. The lightness, red and yellow color of cured leaf grown in low productive field was remarkably low. As compared with Burley 21, the contents of total alkaloid and total nitrogen and shatter resistance index of cured leaf was somewhat low, while the filling power, lightness, red and yellow color were slightly high. Total nitrogen content of cured leaf was increased remarkably by nitrogen addition, but total alkaloid was not increased though the nitrogen fertilizer being applied above 22.5kg/10a. The filling power and shatter resistance index of cured leaf grown in high nitrogen plot, and the lightness and yellow color were low while the red color was relatively high. It comes into question that the visual quality being increased as well as increment of yield and nitrogenous compounds by nitrogen addition in high productive field. In low productive field, it is considerable that nitrogen addition for high yield should be prohibited because it causes the decrement of yield and quality, on the contrary.

• 대한건축학회논문집:구조계
• /
• 제34권3호
• /
• pp.37-42
• /
• 2018

The use of fly ash in construction materials is increasing worldwide due the various advantages of using it, such as to produce durable concrete, or to use less cement and thus lower carbon dioxide emissions. The quality of fly ash is often determined by loss on ignition value (LOI), where an upper limit of LOI is set in each country for quality control purpose. However, due to many reasons, production of high LOI fly ash is increasing that cannot be utilized in concrete, ending up in landfill. In this study, the effect of fly ash use in cementitious materials on nitrogen oxides adsorption is examined. In particular, the effect of using high LOI, and thus high carbon content fly ash on nitrogen oxides adsorption is investigated. The results suggest that the higher carbon content fly ash is related to higher nitrogen dioxide adsorption, although normal fly ash was also more effective in nitrogen dioxide adsorption than ordinary portland cement. Also, higher replacement rate of up to 40% of fly ash is beneficial for nitrogen dioxide adsorption. These results demonstrate that high carbon fly ash can be used as construction materials in an environmentally friendly way where strength requirement is low and where nitrogen oxides emissions are high.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
• /
• pp.568-569
• /
• 2006

The use of the nickel free, high nitrogen stainless steel powder and nitriding during sintering of iron based materials have been shown as an alternative way to the conventional PM stainless steels containing nickel. Nitrogen as an alloying element for iron improves in an effective way the properties of sintered alloyed steels. The powder metallurgy route is a suitable way to introduce nitrogen into these alloys and, in particular, to produce high nitrogen (close to the solubility limit) stainless steels. The paper presents and discusses the nitriding behavior of nickel-free stainless steels produced by powder metallurgy method. Alloyed melt was atomized by nitrogen and in this way nitrogen was introduced into the powder. Further nitriding occurred during sintering in a nitrogen atmosphere. For comparison, compacts having the same composition as an alloyed powder were produced from elemental powders mixture. Sintering-nitriding behaviour of investigated materials has been controlled by dilatometry, chemical and X-Ray phase analysis and metallography. Mechanical properties of sintered compacts were also measured.

• Journal of Microbiology and Biotechnology
• /
• 제28권12호
• /
• pp.2019-2028
• /
• 2018

Natural astaxanthin mainly derives from a microalgae producer, Haematococcus pluvialis. The induction of nitrogen starvation and high light intensity is particularly significant for boosting astaxanthin production. However, the different responses to light intensity and nitrogen starvation needed to be analyzed for biomass growth and astaxanthin accumulation. The results showed that the highest level of astaxanthin production was achieved in nitrogen starvation, and was 1.64 times higher than the control group at 11 days. With regard to the optimization of light intensity utilization, it was at $200{\mu}mo/m^2/s$ under nitrogen starvation that the highest astaxanthin productivity per light intensity was achieved. In addition, both high light intensity and a nitrogen source had significant effects on multiple indicators. For example, high light intensity had a greater significant effect than a nitrogen source on biomass dry weight, astaxanthin yield and astaxanthin productivity; in contrast, nitrogen starvation was more beneficial for enhancing astaxanthin content per dry weight biomass. The data indicate that high light intensity synergizes with nitrogen starvation to stimulate the biosynthesis of astaxanthin.

• 한국산업융합학회 논문집
• /
• 제5권3호
• /
• pp.213-218
• /
• 2002

Total nitrogen is a major pollutant which mostly causes eutrophication and red tide. Wastewater effluent from printing of cotton-viscose rayon containing high concentrations of total nitrogen can not be effectively treated with a typical biological treatment process. This paper provides a new treatment process and experimental results for the removal of high strength nitrogen from dyeing wastewater. The optimum conditions of air stripping for the removal of total nitrogen include around pH 12, temperature $60^{\circ}C$ with 60 minutes of stripping time. In case of a filtration-air stripping process, an initial level ($500mg/{\ell}$) of total nitrogen was significantly reduced to below $60mg/{\ell}$. Deconite was synthesised for further decomposition of organic nitrogen. Thus, a filtration-decomposition-air stripping process was possibly achieved, by which a high level ($900mg/{\ell}$) of total nitrogen was effectively removed to below $60mg/{\ell}$ P. Finally, a continuous new process for the removal of total nitrogen is proposed and confirmed, based on batch experimental results, and its process validity is further discussed throughout.

• 한국작물학회지
• /
• 제58권3호
• /
• pp.213-219
• /
• 2013

A field study was conducted to understand nitrogen use efficiency of high yielding Japonica rice varieties under three levels of nitrogen fertilizer (90, 150 and 210 kg N $ha^{-1}$) in Iksan, Korea. Two high yielding rice varieties, Boramchan and Deuraechan, and an control variety, Dongjin2, were grown in fine silty paddy. Nitrogen use efficiencies (NUE) were 83.3, 56.3, and 41.2 in 90, 150, and 210 kg N $ha^{-1}$ fertilizer level, respectively. Total nitrogen uptake varied significantly among nitrogen levels and varieties. Variety Dongjin2 showed the highest nitrogen uptake efficiency (NUpE), while Boramchan and Deuraechan showed higher nitrogen utilization efficiency (NUtE). However, Nitrogen harvest index (NHI) was higher in Boramchan (0.58) than Deuraechan (0.57) and Dongjin2 (0.53). Rough rice yield showed linear relationship with total nitrogen uptake ($R^2$=0.72) within the range of nitrogen treatments. Boramchan produced significantly higher rough rice yield (8546 kg $ha^{-1}$) which mainly due to higher number of panicles per $m^2$ compared to Deuraechan (7714 kg $ha^{-1}$). Deuraechan showed higher number of spikelets per panicle, but showed lower yield due to lower number of panicle per $m^2$. Rice varieties showed different nitrogen uptake ability and NUE at different nitrogen level. Plant breeders and agronomist should take advantage of the significant variations and relationships among grain yield, NUpE, and NUE.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
• /
• pp.229-234
• /
• 2002

The variation of HAZ toughness with nitrogen content and weld cooling rate was investigated and interpreted in terms of both microstructure and the amount of free nitrogen. The presence of free nitrogen in HAZ was investigated by internal friction measurement and its amount was measured by hydrogen hot extraction analysis. Both nitrogen content and weld cooling rate influenced HAZ microstructure and high toughness was obtained at a mixed microstructure of acicular ferrite, feffite sideplate and polygonal ferrite. If nitrogen content is too low or cooling rate is too fast, bainitic microstructure is obtained and toughness is low. On the other hand, if nitrogen content is too high or cooling rate is too slow, coarse polygonal ferritic microstructure is obtained and toughness is deteriorated again. ill addition to the microstructural change, high nitrogen content also resulted in a large amount of free nitrogen. Therefore, nitrogen content should be kept as low as possible even if the mixed micostructure is obtained. In this experimental condition, the maximum toughness was obtained at 0.006% nitrogen content when weld cooling time ($\Delta$t$_{8}$5/)) is 60s.TEX>5/)) is 60s.

• 한국재료학회지
• /
• 제23권9호
• /
• pp.483-488
• /
• 2013

Over the past few decades, high-nitrogen austenitic steels have steadily received greater attention since they provide a unique combination of high strength and ductility, good corrosion resistance, and non-magnetic properties. Recently, highnitrogen 18Mn-18Cr austenitic steels with enhanced strength have been developed and widely used for generator retaining rings in order to prevent the copper wiring from being displaced by the centrifugal forces occurring during high-speed rotation. The high-nitrogen austenitic steels for generator retaining ring should be expanded at room temperature and then stress relief annealed at around $400^{\circ}C$ to achieve the required mechanical properties. In this study, four kinds of high-nitrogen 18Mn-18Cr austenitic steels with different nitrogen content were fabricated by using a pressurized vacuum induction melting furnace, and then the effects of nitrogen content, cold working, and stress relieving on tensile properties were investigated. The yield and tensile strengths increased proportionally with increasing nitrogen content and cold working, and they further increased after stress relieving treatment. Based on these results, a semi-empirical equation was proposed to predict the tensile strength of highnitrogen 18Mn-18Cr austenitic steels for generator retaining rings. It will be a useful for the effective fabrication of high-nitrogen 18Mn-18Cr austenitic steels for generator retaining rings with the required tensile properties.