• Journal of Sensor Science and Technology
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• v.9 no.6
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• pp.455-460
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• 2000

Zinc oxide(ZnO) thin films were cathodically deposited on ITO glass from an aqueous zinc nitrate electrolyte. Three main fabrication parameters were taken into account : deposition potential, solution concentration and growth temperature. Different layers of ZnO thin films grown by varying the three parameters were studied by X-ray diffraction, scanning electron microscope and optical absorption spectroscopy. The prepared ZnO thin films were shown as a hexagonal wurtzite structure on the X-ray diffraction patterns and the good quality of ZnO thin films were obtained by potentiostatic cathodic deposition at -0.7V vs. Ag/AgCl reference electrode onto ITO glass from aqueous 0.1 mol/liter zinc nitrate electrolyte at $60^{\circ}C$.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1164-1168
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• 2007

질소 및 인 동시제거 공정 중 대표적인 연속회분식반응조(Sequencing Batch reactor: SBR)는 비교적 간편한 운전방법과 저렴한 건설비, 유입수의 부하변동에 큰 영향을 받지 않는 소규모 하수처리에 적합한 공정으로 알려져 있다. 또한 SBR 공정은 기존 활성슬러지 공법에 비해 적은 부지로 많은 양의 폐수를 처리할 수 있고 유입수 수질 및 유량변동에 따라 다양한 운전주기를 변화할 수 있으며, 유기물 제거뿐만 아니라 반응조의 변형에 의해 영양염류의 제거가 가능한 장점이 있다. 본 연구에서는 bench scale SBR 실험을 통하여 질산염의 탈질속도 및 용해성 인의 흡수와 방출속도를 측정하고, SBR 공정의 무산소조건에서 인흡수 및 탈질을 동시에 수행하는 DPB 존재의 가능성을 파악하고자 하였다. 연구결과 무산소조건에서 S-P의 방출과 흡수가 동시에 진행되었으며, 무산소조건에서 S-P의 방출속도는 $0.08{\sim}0.94\;kgS-P/kgMLSS{\cdot}d$, 흡수속도는 $0.012{\sim}0.1\;kgS-P/kgMLSS{\cdot}d$를 나타내었다. 무산소조에서 S-P의 방출 및 흡수가 진행되는 동안 탈질과정도 함께 진행되었으며, 각각의 F/M비에서 탈질속도를 측정한 결과 F/M비 $0.44\;kgCOD/kgMLSS{\cdot}d$에서는 최대 $0.16\;kgNO_3^-N/kgMLSS{\cdot}d$의 탈질속도를 나타내었다. S-P이 방출되지 않는 경우와 방출되는 경우의 비탈질속도를 비교한 결과 S-P이 방출되지 않는 경우의 비탈질속도가 S-P이 방출되는 경우의 비탈질속도보다 높았다. 이렇게 S-P이 방출되는 경우의 비탈질속도가 더 낮은 이유는 무산소 조건에서 탈질과 S-P의 방출 및 흡수가 동시에 일어나는 경우 S-P의 방출에 관여하는 미생물과 탈질에 관여하는 미생물간의 경쟁반응 때문으로 판단된다.응답법의 적용이 가능함을 보였고, 이는 보다 복잡한 관망에서의 천이류 해석이 가능함을 시사한다.$경상도지리지$\lrcorner$(慶尙道地理志)에는 상주가 8곳으로 1/3의 자기 생산을 담당하고 있었다. $\ulcorner$경상도지리지$\lrcorner$(慶尙道地理志)에는 $\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와 동년대에 동일한 목적으로 찬술되었음을 알 수 있다. $\ulcorner$경상도실록지리지$\lrcorner$(慶尙道實錄地理志)에는 $\ulcorner$세종실록$\lrcorner$(世宗實錄) $\ulcorner$지리지$\lrcorner$(地理志)와의 비교를 해보면 상 중 하품의 통합 9개소가 삭제되어 있고, $\ulcorner$동국여지승람$\lrcorner$(東國與地勝覽) 에서는 자기소와 도기소의 위치가 완전히 삭제되어 있다. 이러한 현상은 첫째, 15세기 중엽 경제적 태평과 함께 백자의 수요 생산이 증가하자 군신의 변별(辨別)과 사치를 이유로 강력하게 규제하여 백자의 확대와 발전에 걸림돌이 되었다. 둘째, 동기(銅器)의 대체품으로 자기를 만들어 충당해야할 강제성 당위성 상실로 인한 자기수요 감소를 초래하였을 것으로 사료된다. 셋째, 경기도 광주에서 백자관요가 운영되었으므로 지방인 상주지역에도 더 이상 백자를 조달받을 필요가 없이, 일반 지방관아와 서민들의 일상용기 생산으로 전락하여 소규모화 되었을 것이라고 사료된다.장 운동기능을 향상시키는 유효성분의 보강 등이 필요하다는 점도 알 수 있었다.더불어 산화물질 해독에 관여하는 다른 유전자

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.515-521
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• 1997

Tobacco plant was grown for 40 days hydroponically in nutrient solutions composed of different forms of nitrogen, like NO$_3$$^{[-10]}$ -N, NH$_4$$^{＋}$-N, and a mixed formulation of NO$_3$$^{[-10]}$ -N and NH$_4$$^{＋}$-N. Uptake response, nitrate reductase, and glutamine synthetase activity at growth stage were investigated to understand the basic knowledge of nitrogen metabolism. The better growth of shoot and root was observed in the mixed nutrient solution than NO$_3$$^{[-10]}$ -N or NH$_4$$^{＋}$-N, alone. The plant growth in NH$_4$$^{＋}$-N nutrient solution was poor due to ammonium toxicity. The pH of nutrient solution containing NO$_3$$^{[-10]}$ -N increased up to 40 days after transplanting. But the pH of solution containing NO$_3$$^{[-10]}$ -N decreased drastically to 3.42 at 20 days after transplant. The pH in the mixed formulation dropped to pH 3.64 at 30 days after transplant and showed re-increase. It is assumed that nitrogen of NH$_4$$^{＋}$-N form was taken up preferentially at early stage and NO$_3$$^{[-10]}$ -N form was taken up preferentially at middle stage in the treatment with the mixed solution. The result indicates that the relative proportion of nitrogen forms affected the uptake patterns at each growth stages. The contents of chlorophyll and soluble protein were high with the mixed solution. Total nitrogen content was the highest in NH$_4$$^{＋}$-N solution and the content also increased by the application of the mixed type of nitrogen. The amount of nitrate in leaves was high in NO$_3$$^{[-10]}$ -N treatment and the amount of ammonium was high in NH$_4$$^{＋}$-N treatment. The activity of nitrate reductase or glutamine synthetase was highest in the leaves grown in mixed nutrient solution than in those with any other single of nitrogen form.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.1
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• pp.49-56
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• 1999

With ${15}^N$ labeling under split roots system of winter rye (Secale cereale L.) and forage rape (Brassica napus L.) grown at $5^{\circ}C$ and $25^{\circ}C$, the N flows were respectively quantified to investigate the transport of newly absorbed nitrate-N in whole plant level at low temperature. Comparing with $25^{\circ}C$ culture condition, the total absorbed nitrate-N content at $5^{\circ}C$ decreased to 59.3% and 27.1% in winter rye and forage rape during 9 days. About 2.5% and 7.6 % of nitrate-N were transported into roots, respectively, in winter rye and in forage rape at $25^{\circ}C$. These proportions increased at $5^{\circ}C$ to 3.8% and 10.9%, respectively. Total N contents transferred by xylem in winter rye grown and forage rape grown at $25^{\circ}C$ during were 55.9 and 54.4 mg N/plant, respectively. xylem flows at $5^{\circ}C$ were 60.4% and 28.8% lower than at $25^{\circ}C$ for winter rye and forage rape. These valves represented that averagely 96.8 % and 90.8% of total absorbed nitrate-N were transferred to leaves in winter rye and forage rape during 9 days. Phloem flows were the smallest among other N flows and were much less influenced by temperature treatment for two species examined. About 2.5% and 0.5% of absorbed N were recycled into roots by phloem transport at $25^{\circ}C$, respectively, for winter rye and forage rape. These proportions increased to 5.2% and 0.9% at $5^{\circ}C$.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.1
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• pp.35-41
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• 1987

Nitrate nitrogen was absorbed dominantly among the inorganic nitrogen nutrients by tobacco plant. Transport and reduction of $NO_3-N$ in plant tissue were the important metabolism for supplying synthetic N compounds to developing tissues during growth period. Under field and environment-controlled condition tobacco plants were grown and seperated to leaf tissues at stalk positions for investigation of nitrogen transport and assimilation ability during period of rapid vegative growth. The results of studies were summarized as follows: 1. $NO_3-N$ absorbed from roots was transported as inorganic nitrogen through the vascular tissue of leaf veins as resulting from the high $NO_3-N$ ratio of the nitrogen content in leaf veins, but these ratios in mesophyll tissue of the same leaf laminae decreased remarkably in disregard of higher accumulation of nitrogen being compared to midvien. 2. Mesophyll tissue of mature leaves appeared higher value of nitrate reductase activity (NRA) comparing with other tissues, stem, leaf vien, and meristmatic tissue at emergence point with young leaves. 3. Matured leaves at lower position being reducing nitrate nitrogen vigorously observed thick laminae and kept high amount of water in them. 4. Mature leaves of young plant reduced $NO_3-N$ vigorously for supply synthetic N compounds to meristmatic tissues at growing point by the reason of narrow and few leaves at young stage, but in advancing growth period NRA of mature leaves along upper position reached to lower value. This appearence attributed to distribution of organic-N compound demanding for growth to increasing numbers of wide leaves.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.210-216
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• 2017

Recovery of low level nitric acid and sulfuric acid ions, which were contained in wastewater of a wet scrubber for de-NOx and de-SOx from ship engines, was attempted as fertilizing materials. This study utilized a selective extraction method using four organic solvents to precipitate the solid salts of ammonium nitrate and ammonium sulfate. The IR analysis showed almost same composition of the extracted ammonium salts with a commercial product, and recovery rate of nitrogen and sulfuric ions was 89% and 80% respectively. It was found that the selectivity and solubility consequently could be the crucial factors to recover the low level ions from the waste scrubbing water.

• Korean Journal of Environmental Agriculture
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• v.26 no.3
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• pp.223-227
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• 2007

This study was carried out to establish the reasonable level of nitrogen (N) fertilization based on soil nitrate nitrogen $(NO_3-N)$ content for cucumber (Cucumis sativus L.) under plastic film house. Cucumber plants were cultivated with standard and free N fertilization in eight soils which had various amount of $NO_3-N$ ranging from 67 to 343 mg/kg. The yield of cucumber was in the range of 1006 to 2369 g/plant depending on the nitrogen supplying capability of soils. The amount of $NO_3-N$ in the soil was negatively correlated with agronomic efficiency (AE) and N use efficiency (NUE). The critical level of soil $NO_3-N$ content for cucumber in N free fertilization was found to be about 260 mg/kg in Cate-Nelson analysis of variance between soil $NO_3-N$ and AE or NUE. Also the same critical soil $NO_3-N$ content was found in the yield and amount of N uptake of cucumber under N free fertilization. A standard N fertilization was required when soil $NO_3-N$ content was below 70 mg/kg. The optimal application rate of N fertilizer for cucumber in the soils containing $NO_3-N$ between 260-70 mg/kg could be recommended by the equation Y=-1.032X+269.2 (Y: N fertilization rate, kg/ha; X : soil $NO_3-N$ content mg/kg).

• Analytical Science and Technology
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• v.12 no.2
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• pp.130-135
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• 1999

A graphite furnace atomic absorption spectrometry (GFAAS) with matrix modification has been used to determine trace amounts of arsenic, lead and selenium in rice flour samples. A mixed solution of palladium and magnesium nitrate was used as a matrix modifier to convert the analyte elements into a phase of higher thermostability and to increase the volatility of concomitants in graphite furnace. Matrix modification effects by the mixed solution were investigated for several elements (As, Cd, Cu, Pb, Se, Zn). It has been found that the matrix modifier substantially increase the pyrolysis and atomization temperature, and absorbance for As, Pb and Se. The concentration of As, Pb and Se in rice flour samples were determined by standard addition method with Zeeman background correction after microwave acid digestion. In this method the characteristic concentrations of As, Pb and Se are 26 ng/g, 18 ng/g, 24 ng/g on the basis of dry sample respectively.

• Korean Journal of Materials Research
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• v.4 no.4
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• pp.472-476
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• 1994

Phase transformation of PbO-precursor prepared from $Pb(NO_{3})_{2}$ by precipitation technique was observed by TG-DTA, XRD, FT-IR, and Raman spectral analysis. PbO-precursor was derived from an aqueous solution of $Pb(NO_{3})_{2}$ at $45^{\circ}C$ and pH of 9.0. The precipitate showed it to be the mixture of hydrous lead oxynitrate and lead hydroxynitrate. With increasing heat-treatment temperature ranging up to $560^{\circ}C$, the precursor changed to $3Pb(NO_{3})_{2}$ . 7Pb0, $Pb(NO_{3})_{2}$. 5Pb0 and PbO(litharge), in turn. Finally, it transformed to massicot form of PbO above $560^{\circ}C$.

• Journal of the Korean Chemical Society
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• v.29 no.1
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• pp.52-60
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• 1985

Oxides of nitrogen (NO$_x$) in exhaust gases was determined by absorbing the gas in alkaline peroxide solution containing 0.03${\%}$ H2O2 and 0.1N NaOH. About 100 ppm of NO$_x$ was rapidly oxidized to NO$_2$ or N$_2$O$_5$ by H$_2$O$_2$ and required a contact time of 2 minutes with the absorbing solution for complete absorption. With vigorous shaking including air or oxygen gas, high concentration of NO$_x$ (>200 ppm) can be absorbed within 30 minutes. The remaining H$_2$O$_2$ affect the absorbance of color solution strongly. However, the excess H$_2$O$_2$ was completely decomposed by zinc powder 0.5g and the sample solution should be adjusted to the pH range 6.1∼6.6 before the reduction so that conversion of nitrate to nitrite ion is possible. The absorbed NO$_x$ is determined colorimetrically by the diazotization-coupling method with sulfonilamide and NEDA as the coupling agent. The sensitivity of the new method was 4.48 ${\times}$ 10$^4$ as molar absorptivity which was high sensitive compared with that obtained for the usual zinc reduction NEDA method with O$_3$. This method was far more rapid, brief and accurate than previously published O$_3$-NEDA method in Korean industrial standard.