• Journal of Environmental Science International
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• 제16권6호
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• pp.677-682
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• 2007

This study was performed to provide the basic information on characteristics of groundwater pollution in Gyeongsan city. Forty two groundwater samples were collected, and pH, DO, COD, $NH_3-N,\;NO_3^--N$, T-N, $PO_4^{3-}-P$, Cl, Ca, Mg, hardness, evaporate residues and others were investigated. And, ANOVA analyses were carried out to reveal the differences in water pollution indicator values of by industry, commerce/residence and agriculture areas. The results were as follows. 1. The mean values of pH, DO, COD, $NH_3-N,\;NO_3^--N$, T-N, $PO_4^{3-}-P$, Cl, evaporate residues, Ca and hardness were 6.9, $7.9mg/\ell,\;0.4mg/\ell,\;2.44mg/\ell,\;2.73mg/\ell,\;6.06mg/\ell,\;0.82mg/\ell,\;32.72mg/\ell,\;381.67mg/\ell,\;41.53mg/\ell,\;177.17mg/\ell$, respectively. 2. As groundwater became deeper, the values of Cl, Ca, Mg, Na, hardness and evaporate residues remarkably increased, but those of COD, $NH_3^--N,\;NO_3^--N,\;NO_2^-N$, T-N decreased. 3. The values of COD, Cl, Ca, Mg, Na, hardness and evaporate residues were very high in industrial area, and those of $NH_3-N,\;NO_2^--N$, T-N were very high in commercial/residential area, and those of $NO_3^--N$ were a little high in agricultural area. 4. The correlations between depth and each value of Mg, Na, Fe, hardness and evaporate residues were highly positive, and those between DO and each value of Mg, Cu, Fe, hardness and evaporate residues were highly negative. 5. According to ANOVA analyses, the differences in three area groups (industry, commerce/residence and agriculture) on the values of $NH_3-N$, T-N, evaporate residues, hardness, Ca, Mg, K and Fe were significant at 1% level.

• Korean Journal of Agricultural Science
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• 제46권4호
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• pp.907-914
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• 2019

Ammonia (NH₃) that reacts with nitric or sulfuric acid in the air is the major culprit contributing to the formation of fine particulate matter (PM_2.5). NH₃ volatilization mainly originates from nitrogen fertilizer and livestock manure applied to arable soil. Cation exchange capacity (CEC) of peat moss (PM) and zeolite (ZL) is high enough to adsorb ammonium (NH₄⁺) in soil. Therefore, they might inhibit volatilization of NH₃. The objective of this study was to compare the effect of PM and ZL on NH₃ volatilization from upland soil. For this, a laboratory experiment was carried out, and NH₃ volatilization from the soil was monitored for 12 days. PM and ZL were added at the rate of 0, 1, 2, and 4% (wt wt^-1) with 354 N g m^-2 of urea. Cumulative NH₃-N volatilization decreased with increasing addition rate of both materials. Mean value of cumulative NH₃-N volatilization across application rate with PM was lower than that with ZL. CEC increased with increasing addition rate of both materials. While the soil pH increased with ZL, it decreased with PM. Increase in CEC resulted in NH₄⁺ adsorption on the negative charge of the external surface of both materials. In addition, decrease in soil pH hinders the conversion of NH₄⁺ to NH₃. Based on the above results, the addition of PM or ZL could be an optimum management to reduce NH₃ volatilization from the soil. However, PM was more effective in decreasing NH₃ volatilization than ZL due to the combined effect of CEC and pH.

• Journal of the Korean Chemical Society
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• 제26권1호
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• pp.31-35
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• 1982

Novel palladium(II) complexes of the type Pd(IBA-NH)(IBA-NH') and Pd(IBA-NR)2, where IBA-NH and IBA-NR (R: methyl, ethyl, n-propyl, n-butyl, benzyl) represent isonitrosobenzoylacetone imine and its N-alkyl derivatives respectively, have been prepared. The ir, nmr, and electronic spectra of the palladium(Ⅱ) complexes have been studied. It has been determined that the isonitroso group of IBA-NH coordinates to palladium through the oxygen to form 6-membered chelate ring and that of IBA-NH' coordinates to palladium through the nitrogen to form 5-membered ring in square-planar Pd(IBA-NH)(IBA-NH') and it also has been determined that the isonitroso groups of two IBA-NR coordinates to palladium through the nitrogen to form 5-membered rings in square-planar Pd$(IBA-NR)_2$. The coordination manner of the ligands is similar to that of isonitrosoacetylacetone imines obtained by Bose, et $al.^5$.

• The Korean Journal of Ecology
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• 제26권3호
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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.

• Korean Journal of Materials Research
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• 제9권3호
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• pp.257-262
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• 1999

The selective area growth of GaN by metal organic chemical vapor deposition has been carried out on GaN/ sapphire substrate using $SiO_2$ mask. We investgated the effect of growth parameters such as flow rate of $NH_3$(500­~1300sccm) and the growth temperature(TEX>$950~1060^{\circ}C$) on the growth selectivity and characteristics of GaN using the Scanning Electron Microscopy(SEM). The selectivity of GaN improved as flow rate of NH, and growth temperature in­creased. But the grown GaN shapes on the substrate windows was independent of the flow rate of $NH_3$. On the pattern shapes such as circle, stripe, and radiational pattern(rotate the stripe pattern by $30^{\circ}, 45^{\circ}$), we observed the hexagonal pyramid, the lateral over growth on the mask layer, and the difference of the lateral growth rate depending on growth condition.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제8권3호
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• pp.388-395
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• 1998

This paper reports on a thermodynamic analysis for the GaN thick film growth by vapor phase epitaxy method. The thermodynamic calculation was performed using a chemical stoichiometric algorism. The simulation variables include the growth temperature in a range 400~1500 K, the gas ratios $(GaCl_3)/(GaCl_3+NH_3)$ and $(N_2)/(GaCl_3+NH_3)$. The theoretical calculation predicts that the growth temperature of GaN be in the lower range of 450~750 K than the experimental results. The difference in the growth temperature between the simulation and the experiments indicates that the vapor phase epitaxy of GaN is kinetically limited, presumably, due to the high activation energy of thin film growth.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제19권7호
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• pp.611-617
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• 2006

We report the preparation of N doped, p-type ZnO films by post-annealing in $NH_3$ ambient. The properties were examined by XRD, Hall-effect measurement, PL, and SIMS. ZnO films showed better crystallinity and electron concentration of $10^{15}-10^{17}/cm^3$ with post-annealing in $NH_3$ ambient. These films were converted to p-type ZnO by activation thermal annealing process at $800^{\circ}C$ under $N_2$ ambient. The electrical properties of the p-type ZnO showed a hole concentration of $1.06\times10^{16}/cm^3$, a mobility of $15.8cm^2/V{\cdot}s$, and a resistivity of $40.18\Omega{\cdot}cm$. The N doped ZnO films showed a strong photoluminescence peak at 3.306 eV at 13 K, which is closely related to neutral acceptor bound excitons of the p-type ZnO:N. In the SIMS spectra, the incorporation of nitrogen was confirmed.

• Journal of Bio-Environment Control
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• 제1권1호
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• pp.21-27
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• 1992

The effects of different night temperatures and NO$_3$$^{[-10]}$ : NH$_4$$^{+}$ ratios in nutrient solution on the growth and quality of Chinese white cabbage(B. chinensis L. var. chinensis) and Chinese flat cabbage(B. chinensis L. var. rosularis) were studied. The results were summarized as follows. 1. Fresh weight was increased higher in night temperature 15$^{\circ}C$ than 5, 1$0^{\circ}C$, but content of vitamin C and dry weight ratio were increased as night temperature was lower. 2, The growth of Chinese white cabbage and Chinese flat cabbage was bad extremely in NO$_3$$^{[-10]}$ : NH$_4$$^{+}$(0 : 8), and the others were little different 3. In nutrient solution, the higher NO$_3$$^{[-10]}$ -N concentration was, the more content of vitamin C, and the higher NH$_4$$^{+}$-N concentration was, the more dry weight ratio.ratio.

• Journal of Environmental Impact Assessment
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• 제9권1호
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• pp.39-46
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• 2000

Removal of ammonia using the porous ceramic biofilter inoculated with earthworm casts was characterized. By assuming a plug air flow in the biofilter and applying the Michaelis-Menten equation, the maximum removal rate of $NH_3$ was $280.7g-N{\cdot}m^{-3}{\cdot}h^{-1}$($18.0g-N{\cdot}kg^{-1}{\cdot}d^{-1}$) at $30^{\circ}C$. $NH_3$ removal rate was increased as temperature increases from $15^{\circ}C$ to $35^{\circ}C$. The maximum removal rate was $285.8g-N{\cdot}m^{-3}{\cdot}h^{-1}$($18.8g-N{\cdot}kg^{-1}{\cdot}d^{-1}$) at $35^{\circ}C$. At $15^{\circ}C$, the $NH_3$ removal rate was $122.8g-N{\cdot}m^{-3}{\cdot}h^{-1}$($8.1g-N{\cdot}kg^{-1}{\cdot}d^{-1}$). When 210 ppm $NH_3$ was supplied to the biofilter at space velocity of $220h^{-1}$, the removal efficiency of $NH_3$ at 15, 25, 30 and $35^{\circ}C$ was 80, 90, 95, and 96%, respectively. The removal rate of the ceramic biofilter was 3 to 15 times higher than other biofilters comparing the removal efficiency of $NH_3$ per unit volume of carrier. This result indicates that earthworm casts and porous ceramics are very good inoculum source and carrier, respectively, for the $NH_3$-degrading biofilter.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 한국표면공학회 2007년도 추계학술대회 논문집
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• pp.114-115
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• 2007

플라즈마 응용화학기상법을 이용하여 Silicon Nitride (SiN) 박막을 증착하였다. PECVD 공정은 Box Wilson 실험계획표를 이용하여 수행하였다. SiN박막의 전하밀도를 신경망과 유전자 알고리즘을 이용하여 모델링하였다. 개발된 모델을 이용하여 전하밀도에의 $N_2$와 $NH_3$의 영향을 다양한 온도에서 고찰하였다. $N_2$ (or $NH_3$)의 증가에 따라 전하밀도는 증가하였으며, 이는 전하밀도의 [N-H]에의 강하게 의존하고 있음을 보인다. 전하밀도는 고온에서의 $NH_3$의 증가, 또는 높은 $NH_3$ 유량에서의 온도의 증가에 따라 급격히 증가하였다. 굴절률 모델과 비교할 때, 이 같은 현상이 [N-H]의 증가에 기인하는 것으로 해석되었다.