• 농업과학연구
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• 제47권4호
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• pp.1049-1056
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• 2020

Ultrafine dust causes asthma and respiratory and cardiovascular diseases when inhaled. Ammonia (NH3) plays a big role in ultrafine dust formation in the atmosphere by reacting with nitrogen oxides (NOx) and sulfur oxides (SOx) emitted from various sources. The agricultural sector is the single largest contributor of NH3, with the vast majority of emissions ensuing from fertilizers and livestock sector. Interest in using biochar to attenuate these NH3 emissions has grown. This experiment was conducted to study the effects of using rice hull biochar pyrolyzed at three different temperatures of 250℃ (BP 4.6, biochar pH 4.6), 350℃ (BP 6.8), and 450℃ (BP 10.3) on the emission of ammonia from soil fertilized with urea. The emissions of NH3 initially increased as the experiment progressed but decreased after peaking at the 84th hour. The amount of emitted NH3 was lower in soil with biochar amendments than in that without biochar. Emissions amongst biochar-amended soils were lowest for the BP 6.8 treatment, followed in an ascending order by BP 10.3 and BP 4.6. Since BP 6.8 biochar with neutral pH resulted in the lowest amount of NH3 emitted, it can be concluded that biochar's pH has an effect on the emissions of NH3. The results of this study, therefore, indicate that biochar can abate NH3 emissions and that a neutral pH biochar is more effective at reducing gaseous emissions than either alkaline or acidic biochar.

• 한국세라믹학회지
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• 제46권6호
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• pp.583-586
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• 2009

The Tantalum nitride has attracted wide at attention as issues related to the toxicity of Cd-related materials. But in the titration process of Ta$Cl_5$ solution with $NH_4$OH, $NH_4$Cl, as a by product, was remained in the prepared Tantalum precursor. The tantalum precursor with $NH_4$Cl was nitrided by ammonolysis. The red color tone of $Ta_3N_5$ was reduced by the residual $NH_4$Cl reduce. Therefore, amorphous Tantalum precursor was prepared by filtering process with as hydrous ethanol to remove the $NH_4$Cl. In the case of using Tantalum precursor without $NH_4$Cl, we successfully synthesized the Tantalum nitride with good red color. The value of red color tone was improved from $a^*$=36.8 to $a^*$=53.0. The synthesized powder was characterized by XRD, SEM, the Nitrogen / Oxygen Determinator, TG-DTA, and the CIE $L^*a^*b^*$ colorimeter.

• 환경위생공학
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• 제12권3호
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• pp.61-71
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• 1997

This study was conducted to examine the adsorption capacity of $NH_{3}-N$ by natural zeolite for the purpose of investigating the possibility for $NH_{3}-N$ eliminator of korea natural zeolite. The dominant clay minerals of zeolite was clinoptiloite. The amount of $NH_{3}-N$ adsorption by zeplite was not significantly affected by the particle size of zeolite and increased with increasing the ratio of zeolite to the volume of solution. Removal ratio of 100% of NH$_{3}$-N by non, 1st, 2nd regenerated cloumn was continued separately during 4.5, 18, 30hr and this amount was each 0.081, 0.324, 0.540g $NH_{3}-N/zero$.100g. The eluenting amount of K, Ca, Mg was increased on the zeolite cloumn according to that of Na decreased. The amount of 74% of $NH_{3}-N$ was desorved on the zeolite cloumn for regenerating treatment during 8hr. The perfect removal amount was $0.216gNH_{3}-N/zero$.100g on the zeolite cloumn with field sample.

• 대한화학회지
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• 제15권6호
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• pp.312-317
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• 1971

아닐린, o-톨루이딘, o-에틸아닐린, o-클로로아닐린등과 $I_2$사이의 상호작용을 자외선 분광광도법으로 조사한 결과 $CCl_4$ 용액내에서 아닐린 또는 상기 o-치환 아닐린과 $I_2$ 사이에 1:1 착물이 형성됨을알았다. 이들 착물의 실온에서의 형성상수를 구한 결과 다음과 같은값을 얻었다. $C_6H_5NH_2{\cdot}I_2,\;12.8lmole^{-1};\;o-CH_3C_6H_4NH_2{\cdot}I_2,\;9.31l mole^{-1};\;o-C_2H_5C_6H_4NH_2{\cdot}I_2,\;3.15l mole^{-1};\;o-ClC_6H_4NH_2{\cdot}I_2,\;0.576 l mole^{-1}$. 본 실험결과를 전 실험의 결과와 비교하면 $I_2{\cdot}$아민 착물의 안정도가 다음 순으로 감소함을 알 수 있다. $C_6H_5N(C_2H_5)_2 >C_6H_5N(CH_3)_2 >C_6H_5NH_2 >o-CH_3C_6H_4NH_2 >o-C_2H_5C_6H_4NH_2 >o-ClC_6H_4NH_2$ 이들 착물의 상대적 안정도는 치환기의 유발효과와 입체효과에 의하여 설명될 수 있다.

• 생물환경조절학회지
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• 제1권1호
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• pp.21-27
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• 1992

야온과 시용질소의 형태를 달리한 양액이 탑채와 백경채의 생육 및 품질에 미치는 영향을 알아보기 위하여 실시한 실험의 결과는 다음과 같다. 1. 탑채, 백경채 모두 야온 15$^{\circ}C$ 에서 생육이 왕성하여 생체중이 무거웠으나 건물율과 vitamin C의 함량은 온도가 낮아질수록 증가하였다. 2. 양액의 N형태 비율에 따른 백경채의 생육은 NO$_3$$^{-}$ : NH$_4$$^{+}$ 의 비가 0 : 8에서만 극히 생육이 저조하고, 다른 처리구에서는 큰 차이가 없었다. 3. 양액내 NO$_3$$^{-}$-N의 함량이 높을수록 vitamin C의 함량이 많고, NH$_4$$^{+}$-N의 함량이 높을 때는 건물율이 높았다.

• Rapid Communication in Photoscience
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• 제4권4호
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• pp.79-81
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• 2015

The influence of the grain size of the $CH_3NH_3PbI_3$ on the solar cell performance is investigated by controlling the ratio between $CH_3NH_3I$ and $PbI_2$ precursors. As the concentration of the precursors increased from 1.0M to 2.0M, the $CH_3NH_3PbI_3$ grain size increased from ~100nm to ~400nm. The solar cell utilizing the $CH_3NH_3PbI_3$ with large grain size shows improved photocurrent compared to the solar cell utilizing $CH_3NH_3PbI_3$ with small grain size, which is ascribed to the reduced recombination at the boundaries of grains.

• KSBB Journal
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• 제25권1호
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• pp.85-90
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• 2010

An ion selective microelectrode (ISME) was fabricated to measure concentrations of ammonium (${NH_4}^+$-N) and nitrate (${NO_3}^-$-N) according to the depth of nitrifying biofilm. The limits of detectability and validity of results were investigated to evaluate the ISME. The electromotive force (EMF) was directly proportional to the ion concentration, and average detection limits of ${NH_4}^+$ and ${NO_3}^-$ ISME were $10^{-5.14}$ and $10^{-5.18}$ M, respectively. The concentrations of ${NH_4}^+ $-N and ${NO_3}^-$-N in various depths on the nitrifying biofilm were measured by the ISME. When a modified Ludzack-Ettinger (MLE) process was operated at an HRT of 6 h, concentration gradients of ${NH_4}^+$-N in the bulk solution and biofilm at depths of $100\;{\mu}m$ decreased by $70\;{\mu}M$, while ${NO_3}^-$-N increased by $101\;{\mu}M$ and remained constant thereafter. At an HRT of 4 h, concentration gradients of ${NH_4}^+$-N at depths of $500\;{\mu}m$ decreased by $160\;{\mu}M$ and ${NO_3}^-$-N increased by $162;{\mu}M$ and remained constant thereafter. As HRT decreased, the concentration gradients of ${NH_4}^+$-N and ${NO_3}^-$-N between bulk solution and biofilm was higher due to the increase of nitrogen load. Also, the concentration gradients of the ${NH_4}^+$-N and ${NO_3}^-$-N of biofilm in the second aerobic tank were lower than those of the first aerobic tank, suggesting differences of nitrogen load and concentrations of DO between the first and second aerobic tank.

• 한국세라믹학회지
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• 제43권10호
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• pp.595-600
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• 2006

The preparation of $\beta$-SiAlON powder by SHS in the system of $Si-Al-SiO_2-NH_4F(\beta-Si_3N_4)$ was investigated in this study. In the preparation of SiAlON powder, the effect of gas pressure, compositions such as Si, $NH_4F$, \beta-Si_3N_4$ and additive in mixture on the reactivity were investigated. At 50 atm of the initial inert gas pressure in reactor, the optimum composition for the preparation of pure $\beta$-SiAlON was $3Si+Al+2SiO_2+NH_4F$. The $\beta$-SiAlON powder synthesized in this condition was a single phase $\beta$-SiAlON with a rod like morphology.

• 한국자기공명학회논문지
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• 제14권1호
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• pp.18-27
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• 2010

The NMR spectrum and spin-lattice relaxation times, $T_1$, of the $^{1}H$ nuclei in $(NH_{4})_{2}Cd_{2}(SO_{4})_{3}$ single crystals were obtained. The two minima in $T_1$ in the paraelectric phase are attributed to the reorientational motions of the $NH_{4}^{+}$ groups. The $^{1}H\;T_1$ of the $(NH_{4})_{2}Cd_{2}(SO_{4})_{3}$ crystals can be described with Bloembergen- Purcell-Pound (BPP) theory. The experimental value of $T_1$ can be expressed in terms of an isotropic correlation time ${\tau}_H$ for molecular motions by using the BPP theory, and determine the role of protons in these processes.

• 상하수도학회지
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• 제35권6호
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• pp.533-544
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• 2021

전자 및 화학 산업의 초순수 생산 및 원자력 발전소의 부식 제어를 위해 이온교환 수지탑의 성능 파악이 필수적이다. 따라서 본 연구에서는 4종의 H 및 ETAH 형 양이온 교환수지가 채워진 양이온 및 혼상 이온교환수지탑에 미량의 NaCl를 포함하는 에탄올아민(ETA) 및 암모니아(NH₃) 용액을 주입하여 양이온 파과특성을 조사하였다. 조사 결과, 주성분인 ETAH⁺ 및 NH₄⁺와 달리, 미량성분인 Na⁺는 (이론적교환용량의 3배 이상) 시험기간 동안 수지탑 출구에서 파과 및 오버슈팅 현상이 나타나지 않았다. H형 수지탑의 파과현상은 ETAH⁺ 및 NH₄⁺가 순서대로 일어났고, 오버슈팅은 NH₄⁺가 파과할때 ETAH⁺에 대해서 발생했다. 파과영역의 너비로 결정되는 상대적 선택도는 NH₄⁺가 ETAH⁺보다 최대 51.5 % 더 높았다. 유입수 Na⁺ 농도가 높을수록, 선택도는 감소하고 오버슈팅 현상은 증가하였다. 이온교환 수지의 고유 특성을 개선하여 감소시킬 수 있는 Na⁺ 누출은, ETAH형에서 높았고 4종의 양이온수지에 대해 동일하지 않은 것으로 조사되었다.