• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2445-2448
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• 2007

Self-assembled monolayers (SAMs) were formed by adsorption of thioacetyl-terminated tolanethioacetate (TTA) on Au(111) in a 0.5-mM ethanol solution after one day immersion at room temperature. Molecular-scale STM imaging revealed that the TTA SAMs were composed of two mixed phases; an ordered phase with small domains describing a ( × 2 )R30° structure and a disordered phase. Interestingly, after annealing the precovered TTA SAMs on Au(111) at 90 °C for 1 h, the small ordered domains grew unidirectionally, resulting in the formation of unique rod-like domains, which were assigned a ( × 2 )R7° structure. These results will be very useful in understanding the formation and thermal behavior of TTA SAMs on gold surfaces.

• Journal of the Korean Society of Tobacco Science
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• v.19 no.2
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• pp.124-128
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• 1997

Semivolatile components in mainstream smoke of cigarette attached the different type filter were analysed. Based on the main peak of GC profile, benzene, toluene, acetic acid, limonene, acetamide, pyridine, nicotine, phenol, pyrrole, and furfuryl alcohol were identified. The amount delivered of semivolatile components by each filter was evaluated with the ratio of areas of sample vs area% of ISTD. By comparing dual and triple filter to mono filter, the delivery amounts were 52% benzene, 62% toluene and 74% benzene, 84% toluene, respectively. The delivery amount of limonene which was known of tobacco taste component, were 52%, and 93% by dual and triple filter, respectively. Also, delivery amounts of acetic acid which was one of acidic compounds in smoke, were 86% and 83% by dual and triple filter, respectively. When adding the same amount of active carbon, the amounts delivered of vapour phase such as benzene and toluene by dual filter were lower than that of triple filter. But the delivery amounts of acetic acid and phenol by dual filter were higher than that of triple filter. This results assume that the pH of active carbon in filter affect to the adsorption or absorption of triacetin during filter making process.

• Journal of the Korean Ceramic Society
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• v.31 no.7
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• pp.723-730
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• 1994

Stable aqueous dispersion of magnetite colloid was obtained by allowing a fatty acid, such as nonanoic acid, decanoic acid and undecanoic acid, dissociated with NH4OH solution to adsorb on the monomolecular adsorption of oleate. To obtain a stable dispersion, added amounts of sodium oleate and nonanoic acid for magnetite 20g were more than 2.63$\times$10-2 mol and 0.04 mol respectively. In this colloid, good dispersions of magnetite which is sterically stabilized in aqueous system were achieved about pH 7.7. Water-based magnetic fluids using in this study were able to redisperse to water-based magnetic fluids by adding NH4OH solution to dried water-based magnetic fluid powders. Changing a magnetic fluid carrier such as kerosene was also attemped by adding kerosene to dried water-based magnetic fluid powders. In this study, we can obtain a kerosene-based magnetic fluids using drying process.

• Journal of Hydrogen and New Energy
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• v.14 no.1
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• pp.81-95
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• 2003

본 연구는 압력균등화 공정이 추가된 2 컬럼 6 스뎁의 활성탄 PSA공정을 이용하여 비단열, 비등은 조건에서 메탄(80%)과 수소(20%)의 2성분계로부터 수소분리에 관한 연구이다. 공급가스의 압력, 흡착시간, 공급속도와 P/F 비율이 PSA공정에 미치는 영향에 대하여 평가했고 전산모사를 통해 최적조건을 구했다. 전산모사에 의한 최적 조건은 공급속도 17 LPM, 흡착압력 11 atm, P/F 비율이 0.07~0.1로 나타났으며, 이 조건으로부터 순도 99%, 회수율 85% 이상의 수소가스를 얻을 수 있었다.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1463-1471
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• 2015

The surface modified activated carbons (SMACs) were prepared with various $P_2O_5$ concentrations using two activated carbons (ACs: waste citrus peel-based activated carbon and coconut-based activated carbon). The characteristics and adsorptivity of bisphenol A (one of phenolic endocrine disrupting chemicals) were compared between ACs and SMACs. The contents of C, H and N of SMACs were similar to those of ACs, but the content of $P_2O_5$ for the former increased greatly than for the latter, due to the impregnation of $P_2O_5$ into the pores. The specific surface area, total pore volume, average pore diameter and iodine adsorptivity for the former decreased due to the impregnation of $P_2O_5$ into the pores, compared to those for the latter. The adsorptivity of bisphenol A for the former were higher than that for the latter, although specific surface area, total pore volume, average pore diameter and iodine adsorptivity for the former were lower than those for the latter.

• Korean Journal of Pharmacognosy
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• v.33 no.4 s.131
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• pp.395-398
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• 2002

A chemical investigation of Peucedanum praeruptorum has resulted in the isolation of 3 khellactone derivatives, which have inhibitory effects on melanogenesis in Bl6 mouse melanoma cell lines. The khellactone derivatives were isolated from the crude extract of the roots of Pecedanum praeruptorum by a combination of adsorption chromatography and HPLC. The structlues of isolated compounds were identified as 3',4'- diangeloyl-cis-khellactone, 3'-angeloyl- 4'- senecioyl-cis-khel- lactone and,3', 4'-disenecioyl-cis-khellactone by $^1H\;NMR$, $^{13}C\;NMR$ and mass spectral studies and by comparisons of spectral data with reported literatures.

• Journal of the Korean Chemical Society
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• v.6 no.2
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• pp.158-161
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• 1962

Three kinds of acid clay are chosen as samples; sample-I is the Korean acid clay, Sample-II is prepared by heating the mixure of the Korean acid clay with 20% $H_2SO_4$ for 4 hrs., and the sample-III, the reference sample, is the Japanes acid clay supplied by Katayama Chem. Co.. 15 samples are prepared by heating them at temperatures of $100^{\circ}C$, $300^{\circ}C$, $500^{\circ}C$, $700^{\circ}C$, and $900^{\circ}C$ for 6 hrs. separately.The adsorption experiments are carried out on these samples using bromphenol blue water soln.(conc., 0.001%) as adsorbate. It is found that the degree of decoloration depends upon the temperature of thermal treatment, i.e., the higher the temperature the lower the degree of decoloration is. At any specified temperature of thermal treatment, the degree of decoloration is in following order: sample II>sample I>sample III.The X-ray photographs of the samples show that the intensities of a few specified lines decrease with increasing temperatures of thermal treatment.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.4
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• pp.559-571
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• 2006

The overall objective of this research was to find out the interrelation of coagulant and organic matter during rapid mixing process and to identify the change of organic matter by mixing condition and to evaluate the effect of coagulation pH. During the coagulation, substantial changes in dissolved organics must be occurred by coagulation due to the simultaneous formation of microflocs and NOM precipitates. Increase in the organic removal efficiency should be mainly caused by the removal of microflocs formed during coagulant injection. That is, during the mixing period, substantial amount of dissolved organics were transformed into microflocs due to the simultaneous formation of microflocs and NOM precipitates. The results also showed that 40 to 80% of dissolved organic matter was converted into particulate material after rapid mixing process of coagulation. During the rapid mixing period, for purewater, formation of dissolved Al(III) (monomer and polymer) constant by rapid mixing condition, but for raw water, the species of Al hydrolysis showed different result. During the rapid mixing period, for high coagulant dose, Al-ferron reaction increases rapidly. At A/D(Adsorption and Destabilization) and sweep condition, both $Al(OH)_3(s)$ and dissolved Al(III) (monomer and polymer) exist, concurrent reactions by both mechanism appear to cause simultaneous precipitation.

• The Korean Journal of Ceramics
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• v.4 no.3
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• pp.183-188
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• 1998

Gas sensitizations of tin oxide film were investigated by measuring the change of film resistance in various gas atmospheres such as $N_2,\; O_2,\; H_2O$. The main test sample, polycrystalline $SnO_2$ film containing small Sb as a dopant was prepared by a sputtering technique and showed a long term stability in base resistance and thus, in gas sensitivity. The adsorption of oxygen on the film surface as a type of $(O_{ads})$ at the temperature of around $300^{\circ}C$ played important roles in sensor operating mechanism. The roles were ⅰ) the increase of base resistance in ambient air, which consequently lead to high sensitivity and ⅱ) the promotion of fast recovery. The reaction of hydrogen gas with the already adsorbed $(O_{ads})$ ions was considered as a decisive sensitization mechanism of tin oxide film. However, the dissociation of hydrogen molecules on film surface, by direct donation of electron to film also took a major part in the sensitization. The effect of humidity on gas sensitization was found to be negligible at the sensor operating temperature of around $300^{\circ}C$.

• Journal of Environmental Science International
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• v.12 no.3
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• pp.281-286
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• 2003

This study was conducted to evaluate the feasibility of ammonia removal by zeolite adsorption in drinking water treatment. In generally, drinking water treatment process is conducted coagulation/flocculation, sedimentation, sand filtration and disinfection. We tested feasibility with two method, one is powdered zeolite dosing to coagulation tank and the other is to substitute granular zeolite for sand of sand filter. In powdered zeolite test, raw water is used tap water with putting of 2 mg/l of NH$_4$$\^$+/-N. Filtration of granular zeolite was conducted with 80 cm of effective column high and 120 m/d of flow rate. At above 100 mg/1 of zeolite dosage, ammonia concentration was decreased below 0.5 mg/l of NH$_4$$\^$+/-N in powdered zeolite test. But, turbidity was increased to 30 NTU by powdered zeolite dosage. That turbidity was scarcely decreased in generally coagulant using condition in drinking water treatment. In granular zeolite test, ammonia was not detected in treated water until 8 days. This result suggest that using of granular zeolite in sand filter could be removal ammonia in winter. But we need regeneration at zeolite filtration for ammonia removal. So, it is to make clear that zeolite regeneration ability was compared KCl with NaCl. The result reveal that KCl was more excellent than NaCl. Optimum regeneration concentration of KCl was revealed 100 mM. Regeneration efficient was not increased at pH range 10∼12.5.