• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.04a
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• pp.158-159
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• 2013

방염제인 인산암모늄에 질산칼륨을 첨가하여 질산칼륨이 인산암모늄의 방염성능에 미치는 영향을 DSC와 실체현미경으로 분석하였다. 활성화에너지는 키싱거방법을 도입하여 분석하였다. 방염성능 실험으로서 셀룰로스를 연료로 사용하였다. 질산칼륨이 일정량 첨가된 방염제를 사용하는 경우 인산암모늄의 활성화에너지를 높이고 탄화면적을 감소시켜 연소확대를 억제하였다. 방염제인 질산칼륨이 첨가된 인산염을 방염제로 사용하는 경우 질산칼륨의 강한 산화력으로 화염발생 온도를 낮추고 탄화형성을 억제하여 화재진행 속도를 낮추는 것으로 나타났다. 적정량 이하의 질산칼륨이 포함된 방염제의 처리는 연소속도를 높이고 탄화물형성을 감소시킬 수 있음을 제시하였다.

• Journal of the Korean Chemical Society
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• v.26 no.1
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• pp.36-42
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• 1982

Filters were evaluated to use in the collection of ammonia and ammonium salts in the atmosphere. Ammonia from standard gas generator was collected on a glass fiber filter impregnated with a mixture of 3% boric acid and 25% glycerin. The collection efficiency by the impregnated filter was 96.4${\pm}$2.15% in pH control method and 97.4${\pm}$1.06% in the atmosphere for five measurements, respectively. Adsorption and desorption of gaseous ammonia were compared using three commercially available filters; glass fiber, quartz fiber and polycarbonate filters. Both glass and quartz fiber filters indicated some loss of ammonium salts and adsorption of ammonia, respectively. However, polycarbonate filter was found to be satisfactory for the collection of ammonium salts in the atmosphere. The minimum measurable concentration of ammonia was 0.83ppb (ca. 0.63${\mu}g$/$m^3$) by spectrophotometry of the indophenol method for the sample collected by 47mm${\phi}$ filter(20l/min, 60min). The sensitivity of the present method is about 20 folds higher than that of conventional method of bubbler collection followed by spectrophotometry, so that this method makes it possible to measure thevariation of ammoniacal concentrations in the atmosphere for a short time period of about 60 min.

• Journal of the Korean Chemical Society
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• v.20 no.3
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• pp.185-192
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• 1976

Equivalent conductances of ammonium salts such as $NH_4Cl,\;CH_3NH_3Cl,\;(CH_3)_2NH_2Cl,\;(CH_3)_3NHCl\;and\;(CH_3)_4NCl$ have been measured in methanol-water mixtures of various composition (0.0${\sim}$0.6-mole frcation: m. f.) in the concentration range from 0.01 to 0.04 M at $25^{\circ}C$, and limiting equivalent conductances (${\Lambda}_0$) are determined by the analysis of Fuoss Onsager's semiempirical equation.The experimental results are discussed in terms of varing the size of ${\Lambda}_0$ due to the salts species and solvent composition. It has been observed in quite common over all salts that ${\Lambda}_0$ decreases with the increase of m. f. methanol, and the maximum decrement in ${\Lambda}_0$ shows between water and 0.1 m. f., while the plot of ${\Lambda}_0$ vs. m. f. goes through a minimum at 0.4 m. f. and then turns slightly upward. On the other hand, the ${\Lambda}_0$ decrease with the increase of the size of ammonium cation and the larger values ${\Lambda}_0$ are showed in comparison with those of values observed for the corresponding $n-RNH_3Cl$ under the same experimental procedure. All these behaviors are considered to be closely correlated with the structures of solvents and solutes and the significant similarities are compared with the behaviors of partial molar volumes for amine salts in same solvent system.

• Journal of the Korean Chemical Society
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• v.26 no.2
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• pp.88-94
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• 1982

The concentrations of gaseous ammonia and particulate ammonium emitted from a urea plan were measured, and the conversion rate of ammonia to ammonium was estimated. The conversion of ammonia to ammonium has two stages with transport time in the atmosphere. In the initial 15min the conversion rate was 3.2% min$^{-1}$, and thereafter 0.26% min$^{-1}$. The high conversion rate of ammonia to ammonium at the initial period of it's transport might be due to the dissolution of ammonia into water droplets formed by the decrease in temperature of the stack effluent. The concentration of ammonium is further increased by the decomposition of urea in alkaline droplet formed. Half-lives of ammonia gas at initial and latter slag were 16 min and 192 min respectively. No correlation of particulate ammonium concentration to temperature, relative humidity, and concentrations of sulfur dioxide, nitrogen oxides and airborne particulate matter were found in this field measurement.

• YAKHAK HOEJI
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• v.24 no.3_4
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• pp.159-165
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• 1980

Tetrathiocyanatocobaltate[II] forms complexes with tertiary amine salts or quarternary ammonium salts which were extractable from aqueous solution by organic solvent. In order to study composition of the complex, the colored crystalline complexes produced were evaluated with elemental analysis, infrared and mass spectra. And also a novel spectrophotometric method for the determination of tertiary amine salt or quarternary ammonium salt with tetrathiocyanatocobaltate[II] was established by organic solvent extraction within coefficient of variation of 1.06-1.35%.

• Proceedings of the Korean Fiber Society Conference
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• 1993.06a
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• pp.48-48
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• 1993

• Fire Science and Engineering
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• v.30 no.5
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• pp.93-99
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• 2016

This study tested the combustion characteristics of veneer specimens coated with four kinds of ammonium salts. Each veneer specimen was coated three times with 20 wt.% ammonium salt solutions at room temperature. After drying, the combustion characteristics of the specimens coated with chemicals, were investigated using the cone calorimeter (ISO 5660-1, 2). The specimens coated with monoammonium phosphate (MAPP) and, diammonium phosphate (DMPP) showed a 6.7% and, 10.0%, lower mean heat release rate ($HRR_{mean}$), respectively, than that of the uncoated specimen. On the other hand, the specimens coated with MAPP showed a 15.7% higher $CO_{peak}$ production rate and the specimens coated with DAPP showed by 8.2% lower rate than that of the uncoated specimen. The veneer coated with ammonium sulfate (AMSF) and DAPP showed a 9.6% and 33.3% lower the peak smoke production rate ($SPR_{peak}$) than that of the uncoated specimen. In addition, the time to the peak smoke extinction area ($SEA_{peak}$) was delayed by 38.4% in the specimens coated with DAPP than the uncoated specimen. Therefore, DAPP inhibited the combustion properties of the veneer and showed a tendency to reduce smoke production.

• Journal of the Korea Institute of Building Construction
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• v.17 no.2
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• pp.135-140
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• 2017

As an elementary investigation to develop vegetation concrete with a relatively low pH value, magnesia-phosphate composites (MPC) were examined according to the phosphate types including Monoammonium, Monosodium, Monopotassium, Monocalcium, Diammonium, Disodium, Dipotassium, and Diacalcium phosphates. All of the MPC binders, the ratio of magnesia to phosphate was fixed to be 7:3. MPC mortars activated with Disodium, Dipotassium, and Diacalcium phosphates showed no compressive strength gain, even at age of 28 days. Meanwhile, MPC mortars with Monoammonium and Monosodium phosphates developed 28-day compressive strength of more than 34MPa, and showed a relatively low pH value below 9.8. Hence, Monoammonium and Monosodium phosphates have potentials as an activator for producing MPC-based vegetation concrete.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.286-290
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• 2006

New quaternary ammonium chlorides, [alkyldimethyl-[5-(2-phenylthiazol-4-yl]-1,3,4-oxadizol-2-ylmethyl]quaternary ammonium chlorides (ADOQACs): 6] were obtained with high yields by the reaction of compound 5 with N,N-dimethylalkyl amines in isopropyl alcohol. The structures and physical properties of the synthesized compounds were investigated and those surface-active properties were measured. The surface tension ($\gamma_{cmc}$) and the minimal inhibitory concentration (MIC) of compound 6 were found to be influenced by the number of alkyl chain carbon. Especially, compounds 6c and 6d exhibited high anti-bacterial activities and good surface-active properties.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.971-976
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• 2008

Water pollution by ammonium ion and nitrate is a common and growing problem in the ecosystem. Process of biological removal consists of nitrification and denitrification by bacteria. Ammonium is oxidized generally to nitrate by nitrification and nitrate is reduced to dinitrogen gas in the subsequent denitrification process. Although natural zeolite is well known for its ability to preferentially remove ammonium, it is not sufficiently removing ammonium ion and nitrate by adsorption. In order to overcome this problem, a method of biological removal with zeolite is used for simultaneous removal of ammonium and nitrate. As a result, in case of shaking culture with 1% seed and passing through zeolite column, the process revealed that ammonium ion could be removed completely after 14 hours. The removal of nitrate using columns with naturally adsorbed bacteria onto zeolite reached approximately 100% after 4 hours.