• Korean Journal of Soil Science and Fertilizer
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• v.8 no.2
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• pp.105-111
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• 1975

Nitrogen efficiency for grain yield(E) and its relation to grain yield(Y), harvesting index(HI), percent translocation of nitrogen from straw to grain(T), nitrogen uptake amount(N), concentration in grain (GN%) or straw (SN%) and total dry matter yield (TY) among rice varieties (Oryza sativa, old and new varieties) were investigated at four nitrogen nutritional status (high and low fertilizer levels in high and low fertility fields) by simple correlation analysis. Relation between any two of above parameters or total dry matter yield (TY) and nitrogen efficiency for total dry matter yield (TE) was also investigated. 1. E is significantly and positively correlated with T, Y, HI but negatively with SN%, N, GN% and in negative trend with TY. 2. T is significantly and positively with GN% or Y, but negatively with SN%. 3. TE is significantly and positively correlated with TY but negatively with N. 4. The order of E among varieties showed consistency among different nitrogen nutritional environments. 5. From the above facts it was concluded that high yielding varieties have high nitrogen efficiency due to high percent translocation of nitrogen from straw to grain, subsequent low nitrogen concentration in straw and that translocated nitrogen in grain is greatly diluted with photosynthates. 6. Reported physiological characteristics of newly bred high yielding IR lines are well accordance with their high nitrogen efficiency and rice breeding was a selection on the basis of nitrogen efficiency. 7. It is postulated that high nitrogen efficiency varieties for yields have high nitrogen efficiency for root growth in early stage so that uptake more efficient soil nitrogen in later growth stage.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.2
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• pp.147-154
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• 1999

A field experiment with 200, 400 and 600kg-N/ha/year application levels was carried out to study the nitrate nitrogen accumulation of sorghum sudangrass hybrids(Xtragraze II and Civa 1990) at Iksan College Farm in 1995. The nitrate nitrogen content of Xtragraze II and Civa 1990 was increased by the application of nitrogen and decreased as the plant matured, then the nitrate nitrogen content was below the toxic level of ruminant at the level of 200kg-N application during the whole growing period. The nitrate nitrogen content of Xtragraze II and Civa 1990 exceeded the safe level of ruminant at the level of 400kg-N application, and that in Xtragraze II decreased at the low level in the later stage of growth, but that in Civa 1990 was almost kept constantly at the same level. The nitrate nitrogen accumulation of Civa 1990 had a greater tendency than that of Xtragraze II. A sum exceeding 200kg-N does not necessarily result in increase the amount of nitrate nitrogen in sorghum sudangrass hybrids. It is suggested that 400kg-N application may results in toxic level of nitrate nitrogen, and special attention must be given in feeding them.

• Transactions of Materials Processing
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• v.28 no.1
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• pp.43-48
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• 2019

Aluminum nitride (AlN) is used by the semiconductor industry, and is a compound that is required when manufacturing high thermal conductivity. The AlN films with c-axis orientation and thermal conductivity characteristic were deposited by using the Pulsed Laser Deposition (PLD). The AlN thin films were characterized by changing the deposition conditions. In particular, we have researched the AlN thin film deposited under optimal conditions for growth atmosphere. The epitaxial AlN films were grown on sapphire ($c-Al_2O_3$) single crystals by PLD with AlN target. The AlN films were deposited at a fixed temperature of $650^{\circ}C$, while conditions of nitrogen ($N_2$) pressure were varied between 0.1 mTorr and 10 mTorr. The quality of the AlN films was found to depend strongly on the $N_2$ partial pressure that was exerted during deposition. The X-ray diffraction studies revealed that the integrated intensity of the AlN (002) peak increases as a function the corresponding Full width at half maximum (FWHM) values decreases with lowering of the nitrogen partial pressure. We found that highly c-axis orientated AlN films can be deposited at a substrate temperature of $650^{\circ}C$ and a base pressure of $2{\times}10^{-7}Torr$ in the $N_2$ partial pressure of 0.1 mTorr. Also, it is noted that as the $N_2$ partial pressure decreased, the thermal conductivity increased.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.2
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• pp.61-65
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• 2024

HVPE (Hydride vapor phase epitaxy) is a method of manufacturing thin films or single crystals using gaseous raw materials. This is a method that applies the principles of chemical vapor deposition to grow a single crystal of a material with low meltability or high melting point, and is one of the methods that can obtain a gallium nitride (GaN) single crystal. Recently, much research has been conducted to grow aluminum nitride (AlN) single crystals using this method, but good results have not yet been obtained. In this study, we attempted to grow AlN single crystals using the HVPE method. Nitrogen was used as a carrier gas in the growth process, and the growth results according to changes in the amount of nitrogen (N₂) were examined. Changes in growth crystals as the amount of nitrogen increased were confirmed. The shape of the grown AlN single crystal was observed using an optical microscope, and the rocking curve was measured using double crystal X-ray diffractometry (DCXRD) to confirm the creation of the AlN crystal. The crystallinity of single crystals was also investigated.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.4
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• pp.63-70
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• 1997

The objectives of this study were to find out the optimum treatment conditions for removing nitrogen in a synthetic wastewater by using microorganisms immobilized with PVA-Freezing method. The samples used as influents to the laboratory scale treatment units were a synthetic wastewater. The experiments in this study were mainly directed to collect the data of nitrogen and organic matter removal efficiencies for the different hydraulic and internal recycle rates conditions, temperature and influent C/N ratios. The removal efficiencies of nitrogen and organic matters were investigated for the operating conditions of HRT 2~12hours, internal recycle rates 50~400%, temperatures $15{\sim}30^{\circ}C$ and C/N ratios 2.5~7.5. The adequate internal recycle rate for removing T-N and $BOD_5$ in the synthetic wastewater was found to be about 300% at the temperature of $30^{\circ}C$ when the ratio of carbon contents to the nitrogen (C/N) in the influent was around 5.5. Under these conditions, the final effluent concentrations of T-N and $BOD_5$ were 8.7 and 8.4 mg/l, respectively.

• Journal of the Korean Magnetics Society
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• v.8 no.1
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• pp.6-12
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• 1998

Fe-N(iron-nitrogen) crystal phases were prepared by nitrogen ion implantation into $\alpha$-Fe foil with Plasma Source Ion Implantation (PSII). Ion implantation time of sample is treated 15 minutes(FeN15) and 30 minutes (FeN30). The nitrogen depth profiles measured by Auger electron spectroscopy (AES) were determined to be about 12000 $\AA$ and 4000 $\AA$ for the samples of FeN15 and FeN30, respectively. The results of vibrating sample magnetometer (VSM) show that the saturation magnetization of the samples of as-implanted FeN15 and FeN30 was higher than that of pure $\alpha$-Fe foil, which may be owing to $\alpha$'-$Fe_8N$ or $\alpha$"-$Fe_{16}N_2$ phases. Accordingly this study shows the possibility of the partial formation of $\alpha$' or $\alpha$" phase in iron nitrogen produced by PSII method.II method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.1
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• pp.1-5
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• 2001

Field experiment was conducted during 1993-94 season to determine the pattern of nutrient uptake and productivity of maize/sweet potato intercropping system. Four levels of nitrogen (0, 50, 100 and 150kg N ${ha}_{-1}$) and four levels of potassium (0, 40, 80 and 120kg $K_2$O ${ha}_{-1}$) formed treatment variables. Plants were sampled periodically to determine dry matter and tissue concentrations of N and K in the individual plant components of intercropped maize and sweet potato. Nitrogen and potassium fertilizer did not interact significantly to nutrient uptake by any plant parts of intercropped maize and sweet potato. But application of N fertilizer independently enhanced N uptake in all the plant parts of maize and sweet potato. The uptake of N in leaf, leaf sheath, stem, husk, and cob of maize increased upto 90 days after planting (DAP) but grain continued to accumulate N till its maturity. Sweet potato exhibited a wide variation in N uptake pattern. Sweet potato leaf shared the maximum uptake of N at 50 DAP which rapidly increased at 70 DAP and then declined. Declination of N uptake by petiole and stem were observed after 120 DAP whereas N uptake by tuber increased slowly upto 90 DAP and then rapidly till harvest. Rate of applied K had very little effect on the uptake patterns in different components of intercropped maize. Pattern of K uptake by leaf, petiole and stem of sweet potato showed almost similar trend to N uptake. But uptake of K by tuber increased almost linearly with the K application. Pattern of N and K uptake by grain and tuber paralleled the grain yield of maize and sweet potato respectively. Intercropped productivity of maize and sweet potato found to be better by the application of 100kg N and 120 kg $K_2$O ${ha}_{-1}$

• Journal of Korean Vacuum Science & Technology
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• v.4 no.4
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• pp.97-101
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• 2000

In this study, two kinds of barium strontium titanate (BST) samples were prepared. One is a conventional BST film that is sputtered in a mixture of argon and oxygen. The other is a nitrogen-incorporated BST film that is sputtered in a mixture of oxygen and intentionally added nitrogen instead of argon gas. The structural properties of both of the BST films had not changed significantly with the species of sputtering gas. However, the leakage current of BST films sputtered at ($N_2$+O$_2$) atmosphere was lower than those sputtered at (Ar +O$_2$) atmosphere: 1.9$\times$10$^{-8}$ A/cm$^2$ at 2V for the films prepared at (Ar +O$_2$) atmosphere and 8.6$\times$10$^{-9}$ A/cm$^2$ for the films at ($N_2$+O$_2$) atmosphere. From an XPS analysis, it has been found that nitrogen atoms are incorporated in BST films with a concentration of 1.92 at% and form a certain oxynitride phase. It is proposed that nitrogen atoms are able to fill the oxygen vacancies of BST films during sputtering process, and then the leakage current reduces due to a decrease in the vacancies. The BST films sputtered at ($N_2$+O$_2$) atmosphere have superior electrical properties to the films sputtered at (Ar +O$_2$), without any significant structural changes.

• The Korean Journal of Ecology
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• v.26 no.3
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• pp.135-142
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• 2003

Four legume plants showed better growth by the external nitrogen supply rather than the symbiotic nitrogen fixation only under salt additions. In case of Glycine max and Phaseolus angularis, total nitrogen contents decreased by high salinity level but their amino acid levels significantly increased with the increase of salt treatments and indicated high soluble-/insoluble-N ratios. Cassia tora and Albizzia julibrissin contained less amino acids than G. max and P. angularis but total N (esp. insoluble N fraction) increased with higher salt levels. Asparagine occurred as a main amino acid especially in G. max and P. angularis and can be seen as potential N-storage form in these plants. It might be play an important role for the osmoregulation mechanism under the saline condition. Meanwhile, to investigate what kinds of nitrogen sources are effective for overcoming salt stress on soybean plants, various N forms and concentrations (NH₄NO₃-N, NO₃-N, NH₄NO₃-N; 2.5 and 5 mM) were additionally supplied to the salt gradient medium. Soybean plants treated with NH₄NO₃-N showed the best growth up to 40 mM NaCl and NO₃- fed plants indicated good growth even at 80 mM NaCl treatments. Contrary to NH₄NO₃- and NO₃- fed plants, NH₄/sup +/- fed plants showed remarkable growth reduction and died by 40 and 80 mM NaCl treatments after the first harvest (15th day). Consequently, these results suggest that salt excluding and resistant capacities of soybean plants under NaCl treatments are increased in order of NH₄ - N, control, NO₃- N and NH₄NO₃- N depending on N concentration except NH₄- N treatments.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.5
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• pp.698-701
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• 2000

To prevent surface and underground water pollution, wastewater treatment is essential. Four bench-scale activated sludge units (10 L operational volumes) were operated at 5, 10 and $20^{\circ}C$ for evaluation of treatment efficiencies with typical wastewater from swine housing. The units were set for a 24-hour cycle. As compared to the conventional process, high removal efficiencies for organic substances, nitrogen and phosphorus in swine wastewater were obtained simultaneously with an intermittent aeration process (lAP). The NOx-N produced during an aeration period was immediately reduced to nitrogen gas (e.g. $N_2$ or $N_2O$) in the subsequent non-aeration periods, and nitrification in aeration periods occurred smoothly. Under these conditions, phosphorus removal occurred with the release of phosphorus during the non-aeration periods followed by the excess uptake of phosphorus in the activated sludge during aeration periods. It was confirmed that the lAP had a better ability to remove pollutants under both low temperatures and high nitrogen loading conditions than the ordinary method did. In addition to that, the total emission of $N_2O$ from lAP was reduced to approximately 1/50 of the conventional process for the same loading. By adopting an adequate aeration programme for individual swine wastewater treatment, this system will provide a promising means for nitrogen and phosphorus control without pH control or addition of methanol.