• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.231-231
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• 2010

아직까지 국내에서 사용하는 대부분의 에너지는 화석연료에 의존하고 있다. 지하자원에서 나오는 석탄, 석유와 같은 화석연료는 다른 에너지원에 비해 운송이 간편하고 쉽게 이용할 수 있는 장점이 있지만, 환경오염의 문제성과 오일가상승, 자원의양 및 저장장소가 한정되어 있다는 단점을 가지고 있다. 이에 따라 수소와 같은 대체에너지를 이용하여 환경오염을 예방하고 무한히 사용할 수 있는 에너지원을 개발하기 위한 대체 방안들이 연구되고 있다. 폐기물 가스화시 발생되는 합성가스(CO, $CO_2$, $CH_4$, $H_2$) 내 일차로 생성된 일산화탄소는 수증기와 반응함으로써 이산화탄소로 전환이 가능하다. 잔류 메탄은 이산화탄소를 이용하여 개질함으로써 합성가스내 수소농도를 높일 수 있다. 전환된 잔류가스(CO, $CO_2$, $H_2$)내 일산화탄소는 산소를 이용하여 이산화탄소로 산화시킬 수 있으며, 산화된 이산화탄소는 흡착제를 이용하여 제거가 가능하다. 본 연구에서는 실제 가스화시 발생되는 합성가스를 이용하기 위하여, RPF가스화시 발생되는 합성가스를 직접 포집하여 실험을 진행하였다. 합성가스내 소량의 메탄은 니켈촉매를 이용하여 수소로 전화시켰으며, 잔류하는 일산화탄소는 백금촉매, 이산화탄소는 탄산나트륨 흡착제를 이용하여 연속적으로 제거함으로써 순수한 수소를 제공하였다.

• Journal of the Korean earth science society
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• v.21 no.1
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• pp.81-92
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• 2000

The purpose of this study is to elucidate the characteristic of this study is of attitudinal variation of water quality for nine representative springs in the Halla mountain region. The evolutional processes of the spring water also have been studied. Results of hydrogeochemical analyses show that Gwaneumsa spring is very high in pH. The spring waters from Yungsil, Namguksunwon, Sungpanark Oremok and Gwaneumsa which springs situated lower than 1000m in altitude are relatively high concentrations in chloride, sulphate, nitrate nitrogen and sodium ions, indicating that they are affected by surrounding pollution sources. The concentrations of bicarbonate, sulphate and hydrogen ions in spring waters increase when the precipitation increases, whereas the concentrations of nitrate nitrogen, chloride and calcium ions decrease with increasing amounts of precipitation. The magnesium, sodium and electrical conductivity are nearly independent of the precipitation. The spring waters in the Halla mountain region belong to the groups of sodium or potassium type and bicarbonate type, except the Baegrogdam and Wiseorm spring water.

• Journal of the Korean Chemical Society
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• v.29 no.2
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• pp.121-128
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• 1985

The electrochemical reduction of uranyl ion in aqueous basic media has been examined by d. c. polarography, differential pulsed polarography and cyclic voltammetry. From voltammograms obtained in uranyl solutions containing 0.1M sodium bicarbonate, either with or without the same amounts of sodium tripolyphosphate it is concluded that the first wave corresponds to the reduction of $UO_2^{2+}$ to $UO_2^+$. It is assumed that the uranyl ion undergoes appreciable hydrolysis in these media. The hydrolysis product $UO_2OH^+$ from $UO_2^{2+}$ is not reduced at the first wave, but is reduced at the second wave together with $UO_2^+$. The diffusion current was found proportional to the uranyl concentration in a range between $7.5 {\times} 10^{-4}$ and $3.75 {\times}10^{-3}$M.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.447-448
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• 2009

On this study, the concrete foaming was maximized using Hydrogen peroxide($H_2O_2$) reciprocal decomposition catalyzed by Manganese dioxide($MnO_2$) and Sodium bicarbonate($NaHCO_3$). Also, we study the physical and mechanical properties of lightweight formed concrete through diverse experiment which is to determine the optimal mixing proportion and require strength of the lightweight formed concrete. As a result of an experiment, it is satisefied with overall quality standard on the KS F 4039 and KS F 2459 provision.

• Journal of the Korean GEO-environmental Society
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• v.3 no.4
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• pp.37-49
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• 2002

In this study, it is performed that mix design of grouting materials which high strength, durability and environmentally safe materials for 2 types of suspension, solution grouting. The laboratory model tests such as permeation, solidification tests are performed to find injection effects by the injection pressure, soil condition. And environmental effects of the grouting materials is analyzed through the heavy-metal leaching tests. From the results, micro cement of suspension grouting superior permeation, solidification injection to Portland cement, and phosphoric acid and sodium hydrogen carbonate in solution grouting were similar to micro cement of suspension grouting. When compare to strength of grouted soils, micro cement of suspension grouting showed high compression strength to Portland cement. While, solution grouting showed very low compression strength comparing suspension grouting. Also, in the heavy-metal leaching tests results were satisfied with the environmental regulation standard for raw grouting materials and grouted soil by 7, 14, 28days curing.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.5
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• pp.555-560
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• 2014

This study investigates the effect of sodium bicarbonate ($NaHCO_3$) on growth of S.dimorphus. $NaHCO_3$ concentration was varied from 0 to 2 g-C/L. As a result, the increase in concentration of $NaHCO_3$ up to 1.5 g-C/L increased dry weight of algae. The highest specific growth rate of S. dimorphus was $0.36day^{-1}$ which was obtained at concentration of 0.5 g-C/L $NaHCO_3$. pH showed a large variation range at the concentrations lower than 0.5 g-C/L $NaHCO_3$ whereas inorganic carbon, nitrate and phosphorus removal rates were almost same at the concentrations higher than 0.5 g-C/L $NaHCO_3$ (0.75, 1, 1.25, 1.5, 2 g-C/L $NaHCO_3$). Their average inorganic carbon, nitrate and phosphorus removal rate were 70 mg-C/L/d, 11.3 mg-N/L/d, and 1.6 mg-P/L/d, respectively. Thus, $NaHCO_3$ didn't effect on inorganic carbon, nitrate and phosphorus removal rate of S. dimorphus.

• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.90-100
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• 1986

Along with synthesizing a model oligodeoxyribonuclotide GpApApTpTpCp which had the EcoRI recognition site according to "Phosphotriester Method", reported methods for protecting functions, condensation, deprotection, purifying products, quantification and identification were evaluated and modified. It was realized that oligomers were efficiently synthesized by elongating by dimer unit per step of the condensation and the condensation yields were decreased with increased numbers of the residues. The problems of quantification/identification involved in the oligonucleotide synthesis using small amount of the reactants were solved by employing UV/IR spectrophotometry and hplc/tlc. It was also proved that a nucleotide having the exposed 5'-OH function was well synthesized by condensing a 5'-OH nucleotide and a phosphodiester nucleotide whose molar ratio was intendedly made to be 1 : 1.2 and then detritylating followed by washing with an aqueous solution of sodium bicarbonate. Spectrophotometric and chromatographic data of the nucleotides and their derivatives concerned in this synthetic work were prepared.

• Journal of the Korean Chemical Society
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• v.27 no.6
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• pp.449-456
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• 1983

The facile route of preparing S-2-(${\omega}$-aminoalkylamino) ethyl dihydrogen phosphorothioates, potential chemical radioprotectants, have been studied. Intermediate 3-(2-phthalimidoethyl)-2-oxazolidinone was prepared by a reaction of potassium phthalimide and 3-(2-bromoethyl)-2-oxazolidinone, which was obtained through the alkaline ring closure of a mixture of carbonate and 2,2'-dibromo diethylamine prepared from diethanolamine. This was converted to N-[2-(2-bromoethylamino)ethyl] phthalimide hydrobromide by 30% HBr(gas) in acetic acid and N-(2-bromoethyl)-1,2-ethanediamine dihydrobromide was obtained by reacting the hydrobromide with a solution of HBr-HOAc. N-(2-bromoethyl)-1,3-propanediamine dihydrobromide could be prepared through the Cortese treatment of 2-(3-aminopropylamino) ethanol, which was prepared by a reaction of 1,3-diaminopropane and 2-chloroethanol. These dihydrobromides were treated by sodium thiophosphate in DMF to result S-2-(${\omega}$-aminoalkylamino) ethyl dihydrogen phosphorothioates. The characteristics of each reaction path were discussed in regards to reaction conditions and overall yields and a facile route of preparing each derivative was proposed.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.347-354
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• 2014

Economic evaluation of the manufacturing technology of high-value chemicals through the carbonation reaction of carbon dioxide contained in the flue gas was performed, and analysis of the IRR (Internal Rate of Return) and whole profit along the production plan of the final product was conducted. Through a carbonation reaction with sodium hydroxide that is generated from electrolysis and by using carbon dioxide in the combustion gas that is generated in the power plant, it is possible to get a high value products such as sodium bicarbonate compound and also to reduce the carbon dioxide emission simultaneously. The IRR (Internal Rate of Return) and NPV (Net Present Value) methods were used for the economic evaluation of the process which could handle carbon dioxide of 100 tons per day in the period of the 20 years of plant operation. The results of economic evaluation showed that the IRR of baseline case of technology was 67.2% and the profit that obtained during the whole operation period (20 years) was 346,922 million won based on NPV value. When considering ETS due to the emissions trading enforcement that will be activated in 2015, the NPV was improved to a 6,000 million won. Based on this results, it could be concluded that this $CO_2$ carbonation technology is an cost-effective technology option for the reduction of greenhouse gas.

• Korean Journal of Medicinal Crop Science
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• v.6 no.4
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• pp.305-310
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• 1998

Glucosidic bond at the $C_{20}$ position of the sapogenins was hydrolyzed easily in the lower pH, higher temperature and longer time to give prosapogenins and sugars. The glucosidic bond of saponin at the $C_3\;of\; ginsenoside-Rb_1\;$, which is secondary carbon, was relatively stable due to the low electron density of -0.2. But the bond of saponin at the $C_{20}$ position, which is tertiary carbon with the relatively high electron density of -0.3, was liable to be hydrolyzed even in weak acidic solution by the increase of heating time. On the other hand, fresh and white ginseng contained 4.12 mg/g, 13.05 mg/g of citric acid, 0.68 mg/g, 2.18 mg/g of malonic acid, 1.13 mg/g, 3.68 mg/g of oxalic acid, 2.68 mg/g, 8.62 mg/g of malic acid and 0.13 mg/g, 0.46 mg/g of succinic acid, respectively. Ginseng saponins were very stable in ginseng extract neutralized with sodium carbonate or sodium bicarbonate corresponding to the equivalent amount of the total organic acid in the ginseng.