• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1265-1272
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• 2007

A solid acid catalyst, NiSO4/CeO2-ZrO2 was prepared simply by promoting ZrO2 with CeO2 and supporting nickel sulfate on CeO2-ZrO2. The support of NiSO4 on ZrO2 shifted the phase transition of ZrO2 from amorphous to tetragonal to higher temperatures because of the interaction between NiSO4 and ZrO2. The surface area of 10-NiSO4/1-CeO2-ZrO2 promoted with CeO2 and calcined at 600 oC was very high (83 m2/g) compared to that of unpromoted 10-NiSO4/ZrO2 (45 m2/g). This high surface area of 10-NiSO4/1-CeO2-ZrO2 was due to the promoting effect of CeO2 which makes zirconia a stable tetragonal phase as confirmed by XRD. The role of CeO2 was to form a thermally stable solid solution with zirconia and consequently to give high surface area and acidity of the sample, and high thermal stability of the surface sulfate species. 10-NiSO4/1- CeO2-ZrO2 containing 1 mol% CeO2 and 10 wt% NiSO4, and calcined at 600 oC exhibited maximum catalytic activities for both reactions, 2-propanol dehydration and cumene dealkylation.

• Journal of Conservation Science
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• v.25 no.2
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• pp.147-154
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• 2009

The change of strength and water vapour diffusion resistant by soluble salts was investigated in the tuff and granite used in many stone monuments of Gyeongju area. With $Na_2SO_4$ and $CaSO_4{\cdot}2H_2O$ were treated the rock samples to understand the difference of solubility. The densities of the tested rocks were increased by the impregnation of $CaSO_4{\cdot}2H_2O$ and $Na_2SO_4$. The flexural strength was increased in the tuff samples but decreased in the granite as the salts increased in the pore. In the tuff, the uniaxial compressive strength was increased by $CaSO_4{\cdot}2H_2O$, but decreased by $Na_2SO_4$. In the granite, it was decreased slightly by $CaSO_4{\cdot}2H_2O$, but increased by $Na_2SO_4$. The water vapour diffusion resistant was increased by the salts in both rocks. As results, it was cleared that the mechanical strength colud be increased in early stage of weathering by the accumulation of salt and water vapour diffusion resistant.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.11a
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• pp.38-41
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• 1995

화석연료의 연소에 의하여 방출되는 SO$_2$ 와 NO 에 의한 대기오염의 심각성은 이미 잘 알려져 있으며 그에 따른 배출규제 또한 강화되고 있다. 최근에는 탈황과 탈질을 동시에 처리하는 동시 탈황탈질 공정의 연구가 진행되고 있다. 동시제거 공정은 주로 흡수제/촉매를 토대로 개발되고 있으며 산화구리가 담지된 알루미나 (CuO/${\gamma}$-A1$_2$O$_3$) 흡수제/촉매는 SOx, NOx 동시제거에 효과적인 물질로 알려져 있다. 담지된 CuO 와 담체 A1$_2$O$_3$는 SO$_2$ 와 $O_2$ 존재하에 반응하여 CuSO$_4$ 와 $Al_2$(SO$_4$)$_3$ 가되며 [1] CuSO$_4$ 와 미반응된 CuO 는 NO 제거를 위한 촉매로서의 역할을 하게 된다 [2].

• Cement
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• s.51
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• pp.20-30
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• 1973

1) electron-microprobe를 응용하여 $CaO-SiO_2-Al_2O_3$ 계에서 생성한 $C_2S$, $C_3S$ 에 존재하는 sulfate의 solid, solution을 정량적으로 구할 수 있었으며 이 결과로 $C_2S$ 에 $Al_2O_3$, $SO_3$ 등이 solid soln 등으로 침적되고 이들이 $C_3S$의 생성을 억제한다는 mechanism이 확인되었다. 2) phase equilibrium(상평형)에 의하면 $Na_2SO_4$, $K_2SO_4$는 mineralizer로서 작용하며 $C_3S$ 의 생성을 돕는다. 그러나 $K_2SO_4$ 와 $Al_2SO_3$ 가 결합상태로 존재할 경우는 1,400 $^{\circ}C$에서 광범위한 liquid를 생성하며 quenching하면 glass질과 $\beta-C_2S$ 만이 얻어지고 $C_3S$ 는 생성되지 않는다. 또 이를 1,250 $^{\circ}C$ 까지 서냉하면 $C_2S$ 와 Ca, K, Al, S, 등을 함유한 새로운 물질이 생성된다. 3) $CaO-SiO_2-Al_2O_3-Fe_2O_3$ 계에서 $C_3S$ 의 생성에 미치는 $Na_2SO_4$, $K_2SO_4$ 의 영향을 실험실적으로 검토한 결과 complex interaction이 확인되었으며 $Na_2SO_4$ 는 어떤 경우에는 mineralizing effect를 상실한다는 재미 있는 사실이 발견되었다.

• Journal of environmental and Sanitary engineering
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• v.14 no.1
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• pp.17-23
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• 1999

This study was performed to survey the $SO_2$ level at several underground spaces connected to 5 subway stations (City Hall, Nam, Seoul stations, Hye Hwa and Ulchiro 1 Ga) in Seoul. The period of survey was from July to November, 1997.The results of the study were as follows; 1. The mean concentration of $SO_2$ was $0.057{\pm}0.015ppm$ in all subway stations. The highest $SO_2$ level among the five stations was $0.067{\pm}0.011 ppm$ at City Hall (P<0.01), and the highest with $0.071{\pm}0.013ppm$ at November (P<0.01).2. In underground shopping centers, the mean concentration of $SO_2$ was $0.112{\pm}0.059ppm$. 3. The mean concentration of $SO_2$ at evening with 0.057 pp and morning with 0.053 ppm were significantly higher than at noon with 0.043 ppm(P<0.05). 4. The $SO_2$ level of floor at Kang Nam station with 0.044 ppm was significantly higher than that of platform with 0.37 ppm(P<0.01). 5. For the City Hall stations, the line #1 and line #2 subway spaces show significantly different level of $SO_2$, 0.042ppm and 0.033 ppm respectively (P<0.05).

• Electrical & Electronic Materials
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• v.10 no.8
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• pp.830-835
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• 1997

In this study an experimental investigation has been conducted to remove NOx and SO$_2$simultaneously from a combustion flue gases were consisted of NO-SO$_2$-$CO_2$-$N_2$-O$_2$([NO]o:200ppm and [SO$_2$]o:800ppm) and the injection gases used as radical source gases were NH$_3$-Ar-air and CH$_4$-Ar-air. NOx and SO$_2$removal efficiency and the other by-products were measured by Fourier Transform Infrared(FTIR) as well as SO$_2$, NOx and NO$_2$gas detectors. and SEM images after sampling. The results showed that a significant Nucleating Particle Counter(CNPC) and SEM images after sampling. The results showed that a significant aerosol particle formation was observed during a simultaneous NOx and SO$_2$removal operation in corona radical shower systems. The diameter of aerosol particles was in the range of 0.18 to 3.6${\mu}{\textrm}{m}$ with a maximum fraction of particles at particles diameter of 1${\mu}{\textrm}{m}$. The NOx removal efficiency significantly increased with increasing applied voltage and NH$_3$molecule ratio. The SO$_2$removal efficiency was not significantly effected by applied voltage and slightly increased with increasing NH$_3$molecule ratio. It could be found that it is possible to use CH$_4$for NOx and SO$_2$removal by corona radical shower systems.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.81-86
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• 2007

Hollow fiber membrane G-L contactors are widely used to remove $SO_2$ emitted from industrial facilities. In this work, the mathematical modeling and computer simulation for hollow membrane G-L contactors is carried out to analyze $SO_2$ absorption behavior in hollow fiber membranes. The model is solved with the finite element method using a commercial software. Investigated is the dependency of $SO_2$ removal efficiency and mass transfer characteristics on gas velocities, membrane mass transfer coefficients and physical properties of contactors. The membrane mass transfer coefficients are estimated by fitting the experimental data with the simulated $SO_2$ removal efficiencies. In addition, a design methodology of membrane contactors is suggested.

• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.67-71
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• 2011

The cathodic active material of $Li/SO_2Cl_2$ battery is $SO_2Cl_2$, which is the solvent of an electrolyte. It is referred to as a catholyte, a compound word of cathode and electrolyte. As the battery discharges, the catholyte burns out. And thus, the characteristics of the $SO_2Cl_2$ in the battery determine the capacity. In addition, the transition minimum voltage (TMV) and the voltage delay deviation of $Li/SO_2Cl_2$ battery are due to the passivation film formed by the reaction between an electrolyte and Li. Impurities in the electrolyte, such as moisture or heavy metal ions, will accelerate the growth of the passivation film. Therefore, a technology must be established to purify an electrolyte and to ensure the effectiveness of the purification method. In this research, $LiAlCl_4/SO_2Cl_2$ was manufactured using $AlCl_3$ and LiCl. Its concentration, the amount of moisture, and the metal amount were evaluated using an ionic conductivity meter, a colorimeter, and FT-IR.

• Journal of Environmental Science International
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• v.16 no.2
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• pp.187-195
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• 2007

Long-term passive diffusive samplers(PDS) have been used to measure $NO_2\;and\;SO_2$ concentrations at 21 sampling sites in Daejeon, Korea during the period of January 2000 - December 2002. The spatial distributions of annual $NO_2\;and\;SO_2$ concentrations were mapped. Average annual $NO_2$ concentration over the sampling period was $28.5{\pm}12.5\;ppb$, ranging from 1.2 to 81.7 ppb. Average annual $SO_2$ concentration over the sampling period was $7.7{\pm}4.8\;ppb$, ranging from 0.6 to 26.8 ppb. On average, $NO_2$ concentration was approximately 5.8%(1.6 ppb) larger in 2002. $SO_2$ concentration was decreased by 13%(1.1 ppb) during the sampling period. The seasonal variation of $NO_2\;and\;SO_2$ concentration was observed with a tendency to be higher in fall and winter. $NO_2\;and\;SO_2$, concentrations measured at different site types(patterns of land use) show significant difference. The observed difference in concentration was associated with difference in emissions of $NO_2$ from motor vehicles and $SO_2$ by non-traffic fuel consumption for heating.

• Journal of Plant Biology
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• v.25 no.3
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• pp.135-151
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• 1982

This investigation was carried out to clarify the changes of pigments and soluble protein, and photosystem II activity in the leaves of barley (${SO}_2$-sensitive) and corn (${SO}_2$-resistant) seedlings induced by the ${SO}_2$ fumigation (10, 50ppm). The pH changes of the leaf extract, the content of sulfite and sulfate, the activities of catalase, peroxidase, and polyphenoloxidase were compared in the leaves of barley and corn seedlings induced by ${SO}_2$ fumigation. The results are summarized as follows: An appreciable effect of pH change of leaf extract by ${SO}_2$ fumigation was observed in barley leaves (pH 6.10 to 5.18), but only a small change occurred in corn leaves (pH 5.66 to 5.50). The same pattern of pH changes was recorded when the solution of 0.2N HCl was added to leaf extract, providing lower buffering capacity of the barley leaves than corn leaves. After 2 hours of exposure to 10 ppm ${SO}_2$, the contents of ${SO}^{2-}_3$ and ${SO}^{2-}_4$ were increased in barley leaves, while only ${SO}^{2-}_4$ increased in corn leaves. After fumigation with 10ppm ${SO}_2$ for 2 hours, barley leaves showed significant decreases in activities of catalase, to 17% peroxidase, to 58%, and polyphenoloxidase, to 88%. Corn leaves showed increases in activities of peroxidase, to 136%, and polyphenoloxidase, to 128%. Absorption spectra of pigments obtained from ${SO}_2$-fumigated leaves were gradually decreased with the fumigation time increases, but the decrease was more significant in barley leaves. Fumigation with 50ppm ${SO}_2$ for 2 hours induced the greatest decomposition in carotenoid, followed by chlorophyll a and then chlorophyll b in barley leaves. The ratio of chlorophyll a/b was decreased from 4.1 to 3.6 in barley leaves, but in corn leaves it was maintained almost a constant level(4.9-4.8). The rate of decomposition of chlorophyll and carotenoid in corn leaves was very slow than those in the barley leaves. Fumigation with 50 ppm ${SO}_2$ for 2 hous, decreased the protein content of barley leaves to 59%, and that of corn leaves to 89%, and the extent of decrease in protein content was greater than that of pigments in barley and corn leaves. The rate of DCIP9dichlorophenol indophenol) photoreduction in ${SO}_2$-fumigated leaves was decreased to 18 and 67% in barley and corn leaves, respectively. However, DCIP photoreduction was considerably recovered about 32 and 92% with the addition of DPC(diphenylcarbazide) as an exogenous electron donor in barley and corn leaves, respectively.