• 한국자기공명학회논문지
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• 제6권2호
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• pp.132-141
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• 2002

$^1H$ nuclear magnetic resonance (NMR) relaxations have been investigated in ammonium sulfate $((NH_4)_2SO_4)$ power at temperatures ranging form 102 K to 440 K. There is a bottleneck in the spin-lattice relaxation between the nuclear spin system and the hindered rotation of ammonium ions, which is certified by measuring the relaxation according to the initial condition of the spin system. For temperatures below 318 K the $^1H$ spin-lattice relaxations have double-exponential behaviors with the exponent, n, having a value 2>n>1 initially and n=l after a long time. Above 318 K not only is the relaxation exponential initially with exponent n=1, but it is a single-exponential over the entire time, resulting in one $T_1$ value. The two types of $NH_4^+$ ions have different activation energies for hindered rotation, $E_a^1=0.27{\pm}0.02eV$ and $E_a^11=0.12{\pm}0.0eV$, in the ferroelectric phase.

• 약학회지
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• 제18권3호
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• pp.183-189
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• 1974

Distribution coefficients between nitrobanzene solution and deionized water, show a straight line when the number of alkyl radicals against the logarithm of distribution coefficient of the salts was plotted. After extracting salts of the indicator and the cationic surfactants with organic solvents, and employing the colorimetric method was used. A calculation method of distribution coefficients of the salts in the organic solvent has been suggested and it could be used for the extraction equilibrium of the primary amine, $CH_{3}(CH_2)_{n}NH_3^+$ secondary amine, $CH_{3}(CH_2)_{n}NH_{2}(CH_3)^+$, tertiary amine $CH_{3}(CH_2)_{n}NH(CH_3)_2^+$ and quaternary ammonium, $CH_{3}(CH_2)_{n}N(CH_3)_3^+$MO$^-$salts, (n=3,5,7,11).

• 한국작물학회:학술대회논문집
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• 한국작물학회 2000년도 추계 학술대회지
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• pp.135-136
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• 2000

• 대한화학회지
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• 제16권3호
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• pp.157-165
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• 1972

Ammonium metavanadate의 熱分解過程을 spring balance와 示差熱分析에 의하여 調査하였다. 分解는 $180^{\circ}C{\sim}220^{\circ}C$와 $310^{\circ}C{\sim}330^{\circ}C$이 두 溫度範圍에서 일어나며 最終生成物은 $V_2O_5(orange yellow)$임을 알았다. 第一段階分解는 $NH_3$와 $H_2O$가 2:1의 比로 放出되는 過程임을 $NH_3$의 定量, omegatron mass spectrometer에 의하여 알았으며, 第二段階의 分解는 $NH_3,\;H_2$)外에 N2도 放出된다는 것을 gas chromatography, omegatron mass spectrometer에 의하여 認知하였다. 分解生成物을 X-ray 回折에 의하여 分析한 結果는 空氣中에서의 分解生成物은 $V_2O_5$의 組成을 가진 것이 生成되었음을 確認하였다. 또한 $NH_4VO_3$ 熱分解에 있어서의 活性化에너지는 各各 41.4 kcal/mole 64.4 kcal/mole의 값을 갖었음을 알았다.

• 한국세라믹학회지
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• 제43권4호
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• pp.242-246
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• 2006

[ ${\alpha}-Al_2O_3$ ] nanopowders were fabricated by the thermal decomposition and synthetic of Ammonium Aluminum Carbonate Hydroxide (AACH). Crystallite size of 5 to 8 nm were fabricated when reaction temperature of AACH was low, $8^{\circ}C$, and the highest $[NH_4{^+}][AlO(OH)_n{(SO_4){^-}}_{3-n/2}][HCO_3]$ ionic concentration to pH of the Ammonium Hydrogen Carbonate (AHC) aqueous solution was 10. The phase transformation fem $NH_4Al(SO_4)_2$, rhombohedral $(Al_2(SO_4)_3)$, amorphous-, ${\theta}-,\;{\alpha}-Al_2O_3$ was examined at each temperature according to the AACH. A Time-Temperature-Transformation (TTT) diagram for thermal decomposition in air was determined. Homogeneous, spherical nanopowders with a particle size of 70 nm were obtained by firing the 5 to 8 m crystallites, which had been synthesized from AACH at pH 10 and $8^{\circ}C,\;at\;1150^{\circ}C$ for 3 h in air.

• Environmental Engineering Research
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• 제11권4호
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• pp.173-180
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• 2006

Autotrophic nitrogen removal and its microbial community from a laboratory scale upflow anaerobic sludge bed reactor were characterized with dynamic behavior of nitrogen removal and sequencing result of molecular technique (DNA extraction, PCR and amplification of 16S rDNA), respectively. In the experiment treating inorganic wastewater, the anaerobic granular sludge from a full-scale UASB reactor treating industrial wastewater was inoculated as seed biomass. The operating results revealed that an addition of hydroxylamine would result in lithoautotrophic ammonium oxidation to nitrite/nitrate, and also hydrazine would play an important role for the success of sustainable nitrogen removal process. Total N and ammonium removal of 48% and 92% was observed, corresponding to nitrogen conversion of 0.023 g N/L-d. The reddish brown-colored granular sludge with a diameter of $1{\sim}2\;mm$ was observed at the lower part of sludge bed. The microbial characterization suggests that an anoxic ammonium oxidizer and an anoxic denitrifying autotrophic nitrifier contribute mainly to the nitrogen removal in the reactor. The results revealed the feasibility on development of high performance lithoautotrophic nitrogen removal process with its microbial granulation.

• Environmental Engineering Research
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• 제25권3호
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• pp.274-280
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• 2020

The marine sediment sustains from the anoxic condition due to increased nutrients of external sources. The nutrients are liberated from the sediment, which acts as an internal source. In hypoxic environments, anaerobic respiration results in the formation of several reduced matters, such as N₂ and NH₄⁺, N₂O, Fe²⁺, H₂S, etc. The experimental results have shown that nitrogen and sulfur played an influential, notable role in this biogeochemical cycle with expected chemical reductions and a 'diffusive' release of present nutrient components trapped in pore water inside sediment toward the bulk water. Nitate/ammonium, sulfate/sulfides, and ferrous/ferric irons are found to be the key players in these sediment-waters mutual interactions. Organonitrogen and nitrate in the sediment were likely to be converted to a form of ammonium. Reductive nitrogen is called dissimilatory nitrate reduction to ammonium and denitrification. The steady accumulation in the sediment and surplus increases in the overlying waters of ammonium strongly support this hypothesis as well as a diffusive action of the involved chemical species. Sulfate would serve as an essential electron acceptor so as to form acid volatile sulfides in present of Fe³⁺, which ended up as the Fe²⁺ positively with an aid of the residential microbial community.

• 한국세라믹학회지
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• 제42권3호
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• pp.205-210
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• 2005

Tetraethyl Orthosilicate(TEOS)를 $SiO_2$ 전구체 용액으로 사용하여 Polyacrlamide gel 방법으로 나노 실리카 분말을 합성하였다. 이 gel 공정법은 비교적 간단한 중합법이며, 고분자 망상구조가 $SiO_2$의 응집을 억제하므로 비교적 낮은 하소온도에서 나노입자를 합성할수 있었다. $SiO_2$ 분말입자의 크기는 gel 전구체중의 ammonium persulphate와 N,N'-methylene-bis-acryamide(BIS)의 농도에 영향을 받았다. 실리카 입자의 크기는 ammonium persulphate의 농도가 증가할수록 작아졌으며 그 농도가 0.01M일때 가장 작은 10nm크기의 입자를 얻었다. 또한 그 입자의 크기는 BIS의 농도가 증가할수록 작아졌으며 그 높도가 0.05M일때 입자의 크기는 5nm였다.

• 한국토양비료학회지
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• 제49권3호
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• pp.282-286
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• 2016

This study was carried out to evaluate the effect of application of urea and combination of urea and pig manure compost (PMC) on the occurrence of and the recovery from ammonium ($NH_4{^+}$) toxicity in Chinese cabbage. To identify $NH_4{^+}$ toxicity of the crop four levels of urea at 0, 160, 320, and $480kg\;N\;ha^{-1}$ were applied, in addition, three levels of PMC at 10, 20, and $40M/T\;ha^{-1}$ was also applied with urea $320kg\;ha^{-1}$. For recovery $NH_4{^+}$ toxicity, six levels of sucrose were treated at the amount of 0, 600, 1,200, 1,800, 2,400, and $3,000kg\;C\;ha^{-1}$ at each level of combining treatments of urea and PMC. Our results showed that $NH_4{^+}$ toxicity was occurred at every urea application of $320kg\;N\;ha^{-1}$ regardless of PMC applied to the soils because $NH_4{^+}$ contents in the soils were more than $155mg\;kg^{-1}$ which was found to be the critical level to damage crop growth at 2 days after transplanting (DAT) in this experiment, the more sucrose was applied up to $1,800kg\;C\;ha^{-1}$ for the plants damaged by ammonium toxicity occurred at $320kg\;N\;ha^{-1}$, the greater extents recover the plants from the toxicity. PMC showed the similar effect with sucrose on recovering Chinese cabbage plants from $NH_4{^+}$ toxicity at 30 DAT.

• 분석과학
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• 제8권1호
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• pp.33-40
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• 1995

미량의 hydroxide 이온은 Tetra-n-Butyl Ammonium(TBAC)에 의해 수액상에서 유기상으로 추출될 수 있다. 일차 알코올류, 특히 다이올류의 적은 양을 첨가하면 상전이 촉매계의 거동이 급격히 변하고 과량의 염기를 유기상에서 발견할 수 있다. 정량 측정은 유기상에서 1차, 2차 알콕사이드와 다이올 음이온들의 추출한 양에 대해 행하였다. 한편, 일차 알코올류와 벤질 알코올의 추출에 대한 선택상수들은 수액상과 유기상에서 $Q^+RO^-$($Q^+$ : quaternary 양이온, $RO^-$ : 알콕사이드 이온)와 $Q^+Cl^-$과 같은 이온쌍들의 평형상수와 이 두 상간의 분배계수로 분리되었다. 따라서 $Q^+RO^-$의 선택성에 대한 전제 특성을 본 연구결과에서 언급된 여러 상수들에 대하여 자유에너지에 상응하는 값들을 사용해서 더욱 상세하게 논하였다.