• 원예과학기술지
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• 제31권4호
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• pp.393-399
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• 2013

The effect of solution temperature and nitrogen form on cucumber (Cucumis sativus L.) growth, photosynthesis and nitrogen metabolism was investigated in hydroponic culture. Cucumber plants were grown for 35 days in a greenhouse at three constant solution temperatures ($15^{\circ}C$, $20^{\circ}C$, and $25^{\circ}C$) within a natural aerial temperature ($15-30^{\circ}C$). Four nitrate:ammonium ($NO{_3}^-:NH{_4}^+$) ratios (10:0, 8:2, 5:5, and 2:8 $mmol{\cdot}L^{-1}$) at constant nitrogen (N) concentration of $10mmol{\cdot}L^{-1}$ were applied within each solution temperature treatment. Results showed an increasing solution temperature enhanced plant growth (height, dry weight, and leaf area) in most N treatments. Dry weight accumulation was greatest at the 10:0 $NO{_3}^-:NH{_4}^+$ ratio in the $15^{\circ}C$ solution, the 5:5 ratio in the $20^{\circ}C$ solution and the 8:2 ratio in the $25^{\circ}C$ solution. Photosynthetic rate (Pn) response to solution temperature and $NO{_3}^-:NH{_4}^+$ ratio was similar to that of plant growth. Probably, the photosynthate shortage played a role in the reduced biomass formation. Increasing solution temperature enhanced the nitrate reductase (NR) activity, and further reduced shoots nitrate content. Our results indicate that the optimal ratio of nitrate to ammonium that promotes growth in hydroponic cucumber varies with solution temperature.

• 한국환경농학회지
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• 제22권3호
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• pp.197-202
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• 2003

Phosphorus is one of the major plant growth limiting nutrients, despite being abundant in soils in both inorganic and organic forms. Phosphobioinoculants in the form of microorganisms can help in increasing the availability of accumulated phosphates for plant growth by solubilization. Penicillium oxalicum CBPSTsa, isolated from paddy rhizosphere, was studied for its phosphate solubilization. The influence of various carbon sources like glucose, sucrose, mannitol and sorbitol and nitrogen sources like arginine, sodium nitrate, potassium nitrate, ammonium chloride and ammonium sulphate were evaluated using liquid media with tricalcium phosphate (Ca-P), ferric phosphate (Fe-P) and aluminium phosphate (Al-P). Maximum soluble phosphate of 824 mg/L was found in the amendment of sucrose-sodium nitrate from 5 g/L of Ca-P. Mannitol, sorbitol, and ariginine were poor in phosphate solubilization. While sucrose was better carbon source in solubilization of Ca-P and Al-P, glucose fared better in solubilization of Fe-P. Though all the nitrogen sources enhanced P solubilization, nitrates were better than ammonium In the amendments of ammonium chloride and ammonium sulphate, higher uptake of available phosphates by the fungus was found, and this resulted in depletion of available P in Fe-P amendment Phosphate solubilization was accompanied by acidification of the media, and the highest pH decrease was observed in glucose amendment Among the nitrogen sources, ammonium chloride favored greater pH decrease.

• 한국토양비료학회지
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• 제18권1호
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• pp.63-66
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• 1985

요소(尿素)와 질산(窒酸)암모늄(질안(窒安))이 토양가리(土壤加里)의 이용율(利用率) 및 배추의 수량(收量)에 주는 영향(影響)을 밝히고자 포트시험(試驗)을 한 결과(結果)는 다음과 같다. 1. 질안(窒安)은 요소(尿素)보다 토양(土壤)의 pH를 낮추고 배추에 대(對)한 토양가리(土壤加里)의 이용도(利用度)를 높여서 무가리(無加里) 재배(栽培)에서의 배추의 수량(收量)을 높였다. 2. 배추속(가식부(可食部))을 충실(充實)히 하는데 질안(窒安)은 요소(尿素)보다 더 효과적(效果的)인것 같고 동효과(同效果)는 가리(加里)가 병용(倂用)되므로서 더 현저(顯著)해졌다. 3. 배추의 가식부수량(可食部收量)은 건조(乾燥)배추의 N/K 당량비(當量比)가 낮을수록 많았으며 동비(同比) 약(約) 1.4에서 높은 수량(收量)이 얻어졌다. 이때 건조(乾燥)배추의 K-함량(含量)의 1.2~1.3me/g이었다.

• 생명과학회지
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• 제18권2호
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• pp.162-166
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• 2008

본 연구는 플라스크 배양을 통해 B. indica L3 균주를 가지고 PS-7을 생산할 수 있는 최적 조건을 조사하기 위해서 수행하였다. RSM을 통한 배지의 최적화 실험에서는 whey lactose, glucose, ammonium nitrate 세 가지의 독립변수의 조성에 따라 배양 72시간에 해당하는 DCW, PS-7, 그리고 점도의 변화에 대한 결과를 관찰하였다. 결정 계수(R square)의 값은 PS-7 생산량, DCW, 점성에서 각각 0.72, 0.64, 0.85로 신뢰성 있는 값을 획득하였다. Whey lactose와 glucose의 조합에 따른 PS-7 생산에 미치는 효과를 살펴보면 whey lactose (2%), glucose (1%)에서 최적의 PS-7 생산을 나타내었다. 결론적으로 glucose에 whey lactose를 기반으로 하는 배지 첨가와 C/N 비율이 PS-7의 생산에 큰 영향을 미침을 알 수 있었다.

• Journal of Korean Society for Atmospheric Environment
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• 제21권E1호
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• pp.23-35
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• 2005

Size distribution of particulate water-soluble ion components was measured at Gosan, Korea using a micro-orifice uniform deposit impactor (MOUDI). Sulfate, ammonium, and nitrate showed peaks in three size ranges; Sulfate and ammonium were of dominant species measured in the fine mode ($D_{p} < 1.8 {\mu}m$). One peak was observed in the condensation mode ($0.218\sim0.532{\mu}m$), and the other peak was obtained in the droplet mode ($0.532\sim1.8{\mu}m$). Considering the fact that the equivalent ratios of ammonium to sulfate ranged from 0.5 to 1.0 in these size ranges, it is inferred that they formed sufficiently neutralized compounds such as ($NH_{4})_{2}SO_{4} and (NH_{4})_{3}H(SO_{4})_{2}$ during the long-range transport of anthropogenic pollutants. On the other hand, nitrate was distributed mainly in the coarse mode ($3.1\sim6.2{\mu}m$) combined with soil and sea salt. Two sets of MOUDI samples were collected in each season. One sample was collected when the concentrations of criteria air pollutants were relatively high, but the other represented relatively clean air quality. The concentrations of sulfate and ammonium particles in droplet mode were the highest in winter and the lowest in summer. When the air quality was bad, the increase of nitrate was observed in the condensation mode ($0.218\sim0.282{\mu}m$). It thus suggests that the nitrate particles were produced through gas phase reaction of nitric acid with ammonia. Chloride depletion was remarkably high in summer due to the high temperature and relative humidity.

• Advances in environmental research
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• 제4권4호
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• pp.263-271
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• 2015

In this study, the effect of initial nitrate loading on nitrate removal and byproduct selectivity was evaluated in a continuous system. Nitrate removal decreased from 100% to 25% with the increase in nitrate loading from 10 to $300mg/L\;NO_3-N$. Ammonium selectivity decreased and nitrite selectivity increased, while nitrogen selectivity showed a peak shape in the same range of nitrate loading. The nitrate removal was enhanced at low catalyst to nitrate ratios and 100% nitrate removal was achieved at catalyst to nitrate ratio of ${\geq}33mg\;catalyst/mg\;NO_3-N$. Maximum nitrogen selectivity (47%) was observed at $66mg\;catalyst/mg\;NO_3-N$, showing that continuous Cu-Pd-NZVI system has a maximum removal capacity of 37 mg $NO_3{^-}-N/g_{catalyst}/h$. The results from this study emphasize that nitrate reduction in a bimetallic catalytic system could be sensitive to changes in optimized regimes.

• Environmental Engineering Research
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• 제17권2호
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• pp.111-116
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• 2012

This study investigates the complete removal of nitrate and the recovery of valuable ammonium salt by the combination of nanoscale zero-valent iron (NZVI) and a membrane contactor system. The NZVI used for the experiments was prepared by chemical reduction without a stabilizing agent. The main end-product of nitrate reduction by NZVI was ammonia, and the solution pH was stably maintained around 10.5. Effective removal of ammonia was possible with the polytetrafluoroethylene membrane contactor system in all tested conditions. Among the various operation parameters including influent pH, concentration, temperature, and contact time, contact time and solution pH showed significant effects on the ammonia removal mechanism. Also, the osmotic distillation phenomena that deteriorate the mass transfer efficiency could be minimized by pre-heating the influent wastewater. The ammonia removal rate could be maximized by optimizing operation conditions and changing the membrane configuration. The combination of NZVI and the membrane contactor system could be a solution for nitrate removal and the recovery of valuable products.

• 상하수도학회지
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• 제35권2호
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• pp.135-142
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• 2021

The activity of anaerobic ammonium oxidation (ANAMMOX) immobilized in synthetic media (Poly Ethylene Glycol, PEG) and granular form was evaluated comparatively to investigate the effect of influent nitrogen concentration and exposure of oxygen. In ANAMMOX granule reactor, when concentration of influent total nitrogen increased to 500mg/L, removal efficiency of ammonium, nitrite and nitrate were shown to 90.5±6.5, 96.6±4.9, and 93.2±6.1%, respectively. In the case of the PEG gel, it showed lower nitrogen removal performance, resulting in that the removal efficiency of ammonium, nitrite and nitrate were shown to 83.3±13.0, 96.4±6.1, and 90.3±7.5%, respectively. In second step, when exposed to oxygen, the nitrogen removal performance in the ANAMMOX granule reactor also remained stable, but the activity of PEG gel ANAMMOX was found to be inhibited. Consequently, the PEG gel ANAMMOX was a higher sensitivity than that of granular ANAMMOX with two variables applied in this study.

• 한국대기환경학회지
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• 제26권3호
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• pp.265-275
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• 2010

Mass and ion concentrations of $PM_{10}$ and $PM_{2.5}$ were measured in Yongin, downwind of the Seoul metropolitan area. Twenty-four hour average samples were collected daily for a month or so in spring and fall of both 2007 and 2008. Asian dust occurred twice in each period except in the fall of 2007. During the Asian dust period, nitrate in fine particles decreased since large amount of cations in coarse particles of Asian dust absorbed it. In spring 2008, sulfate as well as ammonium also increased in coarse particles. In spite of occasional Asian dust events, the influence of secondary formation was dominant over the period. Excessive ammonium over sulfate was enough to neutralize nitrate as well. High correlation coefficients between $K^+$ and sulfate, nitrate, and ammonium indicate a close relationship between secondary formation and biomass burning. Biomass burning and open burning are considered to be important sources of chloride.

• 한국추진공학회지
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• 제3권1호
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• pp.48-54
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• 1999

질산암모늄(AN)과 potassium dinitramide(KDN)의 수용액으로부터 염석법에 의해 상안정화 질산암모늄(PSAN)을 제조하는 방법을 나타내었다. 침전제로 사용된 유기 용매는 아세토니트릴이었다. 침전된 결정들의 DSC 분석결과 이들 결정들이 PSAN임을 확인하였고, 침전된 결정중의 KDN 함량이 약 6 무게 % 이상일 때 $0^{\cire}C$에서 $80^{\cire}C$의 온도 범위내에서 AN이 안정화되었다. 제조된 결정들은 고체 로켓 추진제 및 폭약 둥의 제조에서 산화제로 사용될 수 있을 것이다.