• Journal of the Korean Chemical Society
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• v.41 no.5
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• pp.256-265
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• 1997

A rapid and sequential method was studied, which can determine nitrite, nitrate and ammonium ion in soil or water samples with flow injection analysis. Geometric factors including injection volume, length of the reaction coil and flow rate of carrier solution were investigated prior to sample measurement. Nitrite was determined at 540 nm by Griess reaction producing azo dye between N-(1-naphthylethylenediamine dihydrochloride) and sulfanilamide. Nitrate was also measured under the help of reduction mechanism toward nitrite with hydrazine. Ammonium was analyzed at 440 nm with Nessler's reagent. At the optimum condition, the detection limit(S/N=3) has been shown 0.1 ㎍/mL N(NO2-), 0.4 ㎍/mL N(NO3-) and 0.3 ㎍/mL N(NH4+) respectively. The results measured by colorimetry, ion chromatography and FIA were compared showing 80%-125% reasonable match each other. Injection throughput rate could be performed better than 30 times per hour.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.279-286
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• 2007

A submerged biofilm sequencing batch reactor (SBSBR) process, which liquor was internally circulated through sandfilter, was designed, and performances in swine wastewater treatment was evaluated under a condition of no external carbon source addition. Denitrification of NOx-N with loading rate in vertical and slope type of sandfilter was 19% and 3.8%, respectively, showing approximately 5 times difference, and so vertical type sandfilter was chosen for the combination with SBSBR. When the process was operated under 15 days HRT, 105L/hr.m3 of internal circulation rate and 54g/m3.d of NH4-N loading rate, treatment efficiencies of STOC, NH4-N and TN (as NH4-N plus NOx-N) was 75%, 97% and 85%, respectively. By conducting internal circulation through sandfilter, removal performances of TN were enhanced by 14%, and the elevation of nitrogen removal was mainly attributed to occurrence of denitrification in sandfilter. Also, approximately 57% of phosphorus was removed with the conduction of internal circulation through sandfilter, meanwhile phosphorus concentration in final effluent rather increased when the internal circulation was not performed. Therefore, It was quite sure that the continuous internal circulation of liquor through sandfilter could contribute to enhancement of biological nutrient removal. Under 60g/m3.d of NH4-N loading rate, the NH4-N level in final effluent was relatively low and constant(below 20mg/L) and over 80% of nitrogen removal was maintained in spite of loading rate increase up to 100g/m3.d. However, the treatment efficiency of nitrogen was deteriorated with further increase of loading rate. Based on this result, an optimum loading rate of nitrogen for the process would be 100g/m3.d.

• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1185-1189
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• 2005

Two new copper vanadium borophosphate compounds, $(NH_4)(C_2H_{10}N_2)_{5.5}[Cu(C_2H_8N_2)_2]_3[V_2P_2BO_{12}]_6{\cdot}17H_2O,\;Cu-VBPO1\;and\;(NH_4)(C_2H_{10}N_2)_{3.5}[Cu(C_2H_8N_2)_2]_5[V_2P_2BO_{12}]_6{\cdot}18H_2O$, Cu-VBPO2 have been hydrothermally synthesized and characterized by single crystal X-ray diffraction, thermogravimetric analysis, IR spectroscopy, and elemental analysis. The structure of Cu-VBPO1 contains a layer anion, {$[Cu(C_2H_8N_2)_2]_3[V_2P_2BO_{12}]_6$}$^{12-}$, whereas Cu-VBPO2 has an open framework anion, {$[Cu(C_2H_8N_2)_2]_5[V_2P_2BO_{12}]_6$}$^{8-}$. Crystal Data: $(NH_4)(C_2H_{10}N_2)_{5.5}[Cu(C_2H_8N_2)_2]_3[V_2P_2BO_{12}]_6{\cdot}17H_2O$, monoclinic, space group I2/m (no. 12), $\alpha$ = 15.809(1) $\AA$, b = 31.107(2) $\AA$, c = 12.9343(8) $\AA$, $\beta$ = 104.325(1)$^{\circ}$, Z = 2; $(NH_4)(C_2H_{10}N_2)_{3.5}[Cu(C_2H_8N_2)_2]_5[V_2P_2BO_{12}]_6{\cdot}18H_2O$, tetragonal, space group $P4_2$/mnm (no.136), $\alpha$ = 26.832(1) $\AA$, c = 18.021(1) $\AA$, Z = 4.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.251-256
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• 2010

Objective of this research was to investigate the influence of $NH_4^+$ and $NO_3^-$ ratios in liquid feeding on the growth of snapdragon 'Potomac Red' and changes in medium chemical properties. The seeds were sown into 200 plug trays and fertigated once a week with nutrient solution containing various ratios of $NH_4^+$ and $NO_3^-$ such as 0 : 100, 27 : 73, 50 : 50, 73 : 27, and 100 : 0. The total N concentrations were adjusted to 50, 100 and $150\;mg{\cdot}L^{-1}$ in plug stages of 2, 3, and 4, respectively. Determination of seedling growth and analysis of plant tissue and root medum were conducted at 56 days after sowing. The treatment of 27 : 73 ($NH_4^+:NO_3^-$) had the greatest plant height, fresh weight, and dry weight. The N and P contents in 27 : 73 ($NH_4^+:NO_3^-$) treatment based on the above ground plant tissues were 2.39 and 0.39%, respectively, which were the greatest among treatments. The elevation of $NH_4^+$ ratio in fertigation solution decreased tissue Ca and Mg contents, but that did not influence tissue K content. The variations in $NH_4^+:NO_3^-$ ratios impacted the soil solution pH and the difference among treatments had been severe since three weeks after sowing. Elevation of $NH_4^+$ ratios in fertigation solution increased electrical conductivity and concentrations of K, Ca, and Mg in soil solution of root medum. The $NH_4^+$ and $NO_3^-$ concentrations in the soil solution were high in weeks 2, 3, and 4, then decreased gradually as the biomass of seedlings increased. Medium P concentration decreased gradually as seedlings grew, but statistical differences were not observed among treatments.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.413-420
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• 2015

Objective of this study was to investigate adsorption characteristics and kinetic models of $NH_4-N$ to biochar produced from rice hull in respective to mitigation of greenhouse gases. $NH_4-N$ concentration was analyzed by UV Spectrophotometer. For the experiment, the soil texture used in this study was sandy loam soil, and application rates of chemical fertilizer and pig compost were $420-200-370kgha^{-1}$ (N-P-K) and $5,500kgha^{-1}$ as recommended amount after soil test for corn cultivation. Biochar treatments were 0.2-5% to soil weight. Its adsorption characteristic was investigated with application of Langmuir isotherm, and pseudo-first order kinetic model and pseudo-second order kinetic model were used as kinetic models. Adsorption amount and removal rates of $NH_4-N$ were $39.3mg^{-1}$ and 28.0% in 0.2% biochar treatment, respectively. The sorption of $NH_4-N$ to biochar was fitted well by Langmiur model because it was observed that dimensionless constant ($R_L$) was 0.48. The maximum adsorption amount ($q_m$) and binding strength constant (b) were calculated as $4.1mgg^{-1}$ and $0.01Lmg^{-1}$ in Langmuir isotherm, respectively. The pseudo-second order kinetic model was more appropriate than pseudo-first order kinetic model for high correlation coefficient ($r^2$) of pseudo-second order kinetic model. Therefore, biochar produced from rice hull could reduce $N_2O$ by adsorbing $NH_4-N$ to biochar cooperated in sandy loam soil.

• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.153-158
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• 1999

Uptakes of N and P by Phragmites japonica Steudel. are determined in continuous flow tanks as a function of hydraulic retention time (HRT, days) and nutrient concentration (NC). Results show that the uptake was higher at shorter HRT and higher nutrient concentration, and the regression equations were estimated. Mean above ground biomass of Phragmites japonica in the middle reaches of Sagimak stream was 335.92 g/$m^2$, and estimated uptake by this vegetation were 7.31~20.15 NH$_4$-N, 31.15~95.84 NO$_3$-N, and 4.09~11.48 PO$_4$-P mg/$m^2$/day in Sagimak stream, respectively when HRT was 1~5 days. According to this study, it is concluded that Phragmites japonica Steudel. are suitable for water quality improvement of stream through nutrient uptake at short HRT and high concentration.

• Korean Journal of Organic Agriculture
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• v.8 no.2
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• pp.89-96
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• 2000

To reduce loss of nitrogen and generation of ammonia gas during composting, poultry manure and sawdust were mixed at the equivalent ratio and calcium chloride, fused superphosphate and vermiculite were added. Ammonia and sulfurous gas during composting, and NH4-N and NO3-N contents of composts were periodically measured. With the treatments of 0.5∼3% calcium chloride and 3% fused superphosphate, ammonia and sulfurous gas during composting significantly decreased, and especially generation of gases sharply reduced and a increase of calcium chlorde. Extractable NH4-N content in composts treasted with calcium chloride and fused superphosphate were high but extractable NO3-N markedly decreased. In conclusion, the results suggest that it is necessary the additon of 1∼3% calcium chloride or 3% fused superphosphate to reduce loss of nirogen and generation of offensive odor during composting of poultry manure mixed with sawdust.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.1
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• pp.56-60
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• 2017

Mineralization is an important biological process for conversion of organic nitrogen (N) to inorganic N which can be used by plants directly. To investigate the effect of different manures on soil mineralization, the soil amended with cattle (CtM), goat (GM), chicken manure (ChM) and pig slurry (PS) were incubated under in vitro condition and ammonium N ($NH_4{^+}-N$), ammonification rate and ammonia emission were determined for eighty-four days. $NH_4{^+}-N$ was the highest in PS-amended soil for the whole experimental period. $NH_4{^+}-N$ in PS-amended soil was gradually decreased until day 84, whereas it was rapidly decreased for the first 14 days and then slightly increased until 84 days in ChM-, CtM- and GM-amended soil. The ammonification rate showed negative value for the first 14 days in all treatments. From day 14, ammonification rate started to increase in CtM- and ChM-amended soil, whereas it was maintained in GM- and PS-amended soil until day 84. The daily ammonia emission was the highest in PS-amended soil ($41mg\;kg^{-1}d^{-1}$), followed by CtM-, ChM-, and GM-amended soil at day 1. It was gradually decreased until day 84 in all treatments. The total $NH_3$ emission was the highest in PS-amended soil with $0.6mg\;kg^{-1}$ for 84 days, while less than $0.1mg\;kg^{-1}$ in three other plots. These results indicate that different manures showed different soil ammonification rate and $NH_3$ emission.

• Korean Journal of Crystallography
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• v.10 no.2
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• pp.105-109
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• 1999

Ar 기류 하에서 Re(N-C6H3-2,6-i-Pr2)2Cl3(py) (1)과 propionaldehyde (C2H5CHO)가 반응하여 생성된 혼합물에서, [cis-ReCl4(py)(N-C6H3-2,6-i-Pr2)·(NH2-C6H3-2,6-i-Pr2)] (2)가 분리되었다. 이 화합물의 구조가 X-ray 회절법으로 규명되었다. 착물 2의 결정학 자료: 단사정계 공간군 P21/n, a=11.555(1) Å, b=27.066(3) Å, c=11.881(1) Å, β=117.991(8)°, Z=4, R(wR2)=0.0332(0.0851.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.212-212
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• 2012

수소화된 실리콘 질화막은 결정질 태양전지 산업에서 반사방지막 과 패시베이션 층으로 널리 사용되고 있다. 또한, 수소화된 질화막은 금속 소성공정과 같은 높은 공정온도를 거친 후에도 결정질 실리콘 태양전지의 표면층으로서 충족되는 특성들이 변하지 않고 유지되어야 한다. 본 연구에서는 PECVD 장치를 이용한 수소화된 실리콘 질화막의 특성 변화에 대한 경향성을 알아보기 위하여 증착조건의 변수(온도, 증착거리, 무선주파수 전력, 가스비율 등.)들을 다양하게 가변하여 증착조건의 최적화를 찾았다. 이후 수소화된 실리콘 질화막의 전구체가 되는 사일렌(SiH4)과 암모니아(NH3) 가스비를 변화시켜가며 결정질 실리콘 태양전지에 사용되기 위한 박막의 광학 전기 화학적 그리고 표면 패시베이션 특성들을 분석하였다. 가스 비율에 따른 수소화된 실리콘 질화막의 굴절률 범위는 1.90-2.20까지 나타내었다. 결정질 실리콘 태양전지에 사용하기 위한 가장 적합한 특성은 3.6(NH3/SiH4)의 가스비율을 나타내었다. 이를 통하여 PECVD 내에서 구현 할 수 있는 가스의 혼합(SiH4+NH3+N2, SiH4+NH3, SiH4+N2)을 달리하여 박막의 광학적 및 패시베이션 특성을 분석하였다. 이후 $156{\times}156mm$ 대면적 결정질 실리콘 태양전지를 제작하여 SiH4+NH3+N2 의 가스 혼합에서 17.2%의 변환 효율을 나타내었다.