• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.63-69
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• 1998

The treatment of soils and water contaminated with MTBE using the Fenton oxidation was investigated. The effects of dosage of $H_{2}O_{2}$, and Fe$^{2+}$ concentrations, and solution pH on transformation and mineralization in soil were evaluated. Generation of TBA and acetone following Fenton-oxidation of MTBE in water and generation of acetone following Fenton-oxidation of TBA were observed. Therefore TBA and acetone are degradation intermediates of MTBE. There was a large difference of treatment efficiency in Fenton oxidation of MTBE between soil and water system. This may be caused by the complex nature of soil, soil organic matter which can consumed OH $\cdot$ radicals, and interacting with inorganic-soil constituents. The pH of soil was observed to have a significant effect on the chemical oxidation efficient of MTBE in soil The data demonstrated that optimal pH range were pH 3~4 and around 6. The soil batch studies demonstrated that treatment efficiency of MTBE was enhanced by adding additional ferrous salts but Fenton-oxidation occurred in no additional iron which indicated that iron in soil can catalyze the Fenton-oxidation. The most effective parameter of Fentonoxidation was $H_{2}O_{2}$/Fe$^{2+}$ ratio which theocratical ratio is 0.5. The optimal range of this ratio was found to be 0.6~2.3. In evaluating effect of $H_{2}O_{2}$ dosage on treatment efficiency, the increase of $H_{2}O_{2}$ did not always lead to increase of decompositions of MTBE in soil. Fenton oxidation was effective in destroying MTBE in aqueous extracts of contaminated soil and water. Experimental data provided evidence that the Fenton oxidation can effectively remediate MTBE-contaminated water and soil.

• Journal of Environmental Health Sciences
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• v.44 no.2
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• pp.160-168
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• 2018

Objectives: The purposes of the study were to investigate hazardous pollutant emissions changes among group 1 carcinogens. The emissions characteristics were compared with national cancer registration statistics. Methods: A survey of group 1 carcinogen hazardous pollutant emissions (trichloroethylene, benzene, vinyl chloride, formaldehyde, 1,3-butadiene, ethylene oxide, chromium and its compounds, 3,3'-dichloro-4,4-diaminodiphenylmethane, chloromethyl methyl ether, arsenic and its compounds, cadmium and its compounds, o-toluidine) was conducted through a homepage for 2001-2015. The emission of hazardous chemicals and the cancer trend analysis for 2001-2015 were performed using the Korean statistical information service through its homepage as a reference. Results: Emissions of more than 95% of the substances listed as group 1 carcinogens over the last five years were made up of trichloroethylene, benzene, vinyl chloride, formaldehyde, 1,3-butadiene, and ethylene oxide. As a result of the comparison of emission results and cancer incidence rates, carcinogen pollutant emissions showed a tendency to decrease continuously. In addition, the incidence of cancer tended to increase, but showed a tendency to decrease from 2012. Conclusion: The results indicate hazardous pollutant emissions have continued to increase. However, no association between emissions and health effects was shown and more research is needed.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.6
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• pp.107-116
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• 2012

In this study, the trucks(2.9-liter) have been developed to use DME as fuel, and performance test of the vehicle's DME engine, power, emissions, fuel economy and vehicle aspects was conducted. For experiments, the fuel system(common-rail injectors and high-pressure pump included) and the engine control logic was developed, and ECU mapping was performed. As a result, the rail pressure from 40MPa to approximately 65% increase compared to the base injector has been confirmed that. Also, the pump discharge flow is 15.5 kg/h when the fuel rail pressure is 400rpm(40MPa), and the pump discharge flow is 92.1 kg/h when the fuel rail pressure is 2,000rpm(40MPa). The maximum value of full-load torque capability is 25.5 kgfm(based on 2,000 rpm), and more than 90% compared to the level of the diesel engine were obtained. The DME vehicle was developed in this study, 120 km/h can drive to the stable, and calculated in accordance with the carbon-balance method of fuel consumptions is 5.7 km/L.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.135-143
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• 2013

In this study, we suggested effective countermeasure of biodiesel oxidation problems by investigating the oxidation degradation of biodiesels derived from variable resources and the level of oxidation stability of current distributing biodiesel blended fuels (2%) in Korea, and oxidation stability change according to storage time (for 3 month) and biodiesel blending ratio (2, 5, 7, 10%). By the composition analysis results of biodiesel from various resources which are possible to distribute in Korea, the biodiesel from animal fat has poor oxidation stability and cold performance, while the biodiesel from coconut and palm kernel which are considered as future potential raw material showed good oxidation stability and cold performance. The oxidation stability level of current distributing biodiesel blended fuels in Korea was excellent with showing over 30 hours (average 68 hours) stability, but the oxidation stability of the blended fuel with animal fat biodiesel having poor oxidation property (1.22 hours) was rapidly decreased to below 32 hours by mixing only 2%. Therefore, we have to pay attention to quality control of oxidation property, because the oxidation stability problem can be caused by increasing biodiesel blending ratio and diversifying raw materials those have worse property.

• Tribology and Lubricants
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• v.36 no.3
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• pp.161-167
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• 2020

Petroleum is the most used energy source in Korea with a usage rate of 39.5% among the available 1st energy source. The price of liquid petroleum products in Korea includes a lot of tax such as transportation·environment·energy tax. Thus, illegal production and distribution of liquid petroleum is widespread because of its huge price difference, including its tax-free nature, from that of the normal product. Generally, illegal petroleum product is produced by illegally mixing liquid petroleum with other similar petroleum alternatives. In such case, it is easy to distinguish whether the product is illegal by analyzing its physical properties and typical components. However, if one the components of original petroleum product is added to illegal petroleum, distinguishing between the two petroleum products will be difficult. In this research, we inspect illegally produced gasoline, which is mixed with methyl tertiary butyl ether (MTBE) as an octane booster. This illegal gasoline shows a high octane number and oxygen content. Further, we analyze the different types of green dyes used in illegal gasoline through high performance liquid chromatography (HPLC). We conduct component analyses on the simulated sample obtained from premium gasoline and MTBE. Finally, the illegal gasoline is defined as premium gasoline with 10% MTBE. The findings of this study suggest that illegal petroleum can be identified through an analytic method of components and simulated samples.

• Korean Journal of Materials Research
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• v.20 no.11
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• pp.600-605
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• 2010

In order to meet the requirements of faster speed and higher packing density for devices in the field of semiconductor manufacturing, the development of Cu/Low k device material is explored for use in multi-layer interconnection. SiOC(-H) thin films containing alkylgroup are considered the most promising among all the other low k candidate materials for Cu interconnection, which materials are intended to replace conventional Al wiring. Their promising character is due to their thermal and mechanical properties, which are superior to those of organic materials such as porous $SiO_2$, SiOF, polyimides, and poly (arylene ether). SiOC(-H) thin films containing alkylgroup are generally prepared by PECVD method using trimethoxysilane as precursor. Nano voids in the film originating from the sterichindrance of alkylgroup lower the dielectric constant of the film. In this study, methyltriphenylsilane containing bulky substitute was prepared and characterized by using NMR, single-crystal X-ray, GC-MS, GPC, FT-IR and TGA analyses. Solid-state NMR is utilized to investigate the insoluble samples and the chemical shift of $^{29}Si$. X-ray single crystal results confirm that methyltriphenylsilane is composed of one Si molecule, three phenyl rings and one methyl molecule. When methyltriphenylsilane decomposes, it produces radicals such as phenyl, diphenyl, phenylsilane, diphenylsilane, triphenylsilane, etc. From the analytical data, methyltriphenylsilane was found to be very efficient as a CVD or PECVD precursor.

• New & Renewable Energy
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• v.3 no.4
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• pp.98-103
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• 2007

국제 원유가의 지속적인 상승에 따라 화석연료 고갈을 대비한 대체에너지 및 온실가스배출 감소를 위하여 바이오연료의 시용 및 상용보급은 전세계적인 추세이다. 우리나라의 경우 바이오디젤은 2002년부터 시범보급사업(Demonstration & disseminatio을 거쳐 2000년 7월부터 전국주유소를 통하여 경유 중에 바이오디젤 0.5%를 혼합한 BD0.5를 수송용 연료로 도입하여 아시아 최초로 상용보급화를 시행하고 있다. 또한 휘발유 중 바이오에탄올 혼합 연료유 도입을 위한 실증평가연구를 2006년 8월부터 2008년 7월까지 수행중이다. 자동차용 휘발유의 옥탄가 향상을 위해 함산소 기재로 사용되는 MTBE(Methyl Tertiary Butyl Ether)를 바이오에탄올로 대체한 바이오에탄올 혼합연료유는 수분 혼입에 의한 상 분리(Phase separation)와 금속에 대한 부식성 문제를 야기 시킬 수 있다. 바이오에탄올을 서브옥란가솔린(Sub-octane gasoline)에 혼합하여 상 분리 모사실험, 금속류 부식시험, 고무류 침지실험 등 다양한 품질특성평가를 수행하였으며, 이런 결과들을 바탕으로 국내실정에 알맞은 최적의 혼합량(E3, E5)을 도출하였다. 또한 전국에 4개 시범주유소를 운영하여 바이오에탄올 혼합 연료유의 유통 및 보급을 통해 최적의 유통인프라(Distribution infrastructure) 보완 및 구축 방안을 도출 하고자 한다.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.450-455
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• 1998

Pine has been known as a traditional medicinal plant and as showing a physically beneficial function to a human being. Therefore, this study was performed to investigate the physiological activities of main pine neddles. Ethanol extracts from pinus needles did net exhibit any mutagenicity. On the contrary, inhibitory effects of ethanol extract were observed on mutagenicity induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG), 4-nitroquinoline-1-oxide (4NQO), 3-amino-1,4-dimethyl-5H-pyrido-(4,3-b)indol (Trp-P-1) and benzo(a)pyrene $(B({\alpha})P)$ using Salmonella typhimurium reversion assay. On direct-acting mutagen (MNNG, 4NQO) and indirect-acting mutagen (Trp-P-1, $(B({\alpha})P)$, we observed higher inhibitory effect. Stepwise fractionation of the ethanol extract was done by using ether, chloroform, ethyl acetate, butanol and water to obtain effective fraction. Among them, water fractions $(100\;{\mu}g/plate)$ of Pinus thunbergii, Pinus rigida, Pinus densiflora and Pinus koraiensis showed high inhibition of 91.65%, 94.7%, 84.22% and 79.02%, respectively, on the mutagenicity of MNNG in Salmonella typhimurium TA100.

• Natural Product Sciences
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• v.21 no.1
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• pp.30-33
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• 2015

Anthocyanins are water soluble plant pigments which are responsible for the blue, red, pink, violet colors in several plant organs such as flowers, fruits, leaves and roots. In recent years, anthocyanin-rich foods have been favored as dietary supplements and health care products due to diverse biological activities of anthocyanins including antioxidant, anti-allergic, anti-diabetic, anti-microbial, anti-cancer and preventing cardiovascular disease. High-performance countercurrent chromatography (HPCCC) coupled with reversed-phase medium pressure liquid chromatography (RP MPLC) method was applied for the rapid and efficient isolation of cyanidin 3-glucoside (C3G) and peonidin 3-glucoside (P3G) from black rice (Oryza sativa L., Poaceae). The crude black rice extract (500 mg) was subjected to HPCCC using two-phase solvent system composed of tert-butyl methyl ether/n-butanol/ acetonitrile/0.01% trifluoroacetic acid (TBME/B/A/0.01% TFA, 1 : 3 : 1 : 5, v/v, flow rate - 4.5 mL/min, reversed phase mode) to give enriched anthocyanin extract (37.4 mg), and enriched anthocyanin extract was sequentially chromatographed on RP-MPLC to yield C3G (16.5 mg) and P3G (8.7 mg). The recovery rate and purity of isolated C3G were 76.0% and 98.2%, respectively, and those of P3G were 58.3% and 96.3%, respectively. The present study indicates that HPCCC coupled with RP-MPLC method is more rapid and efficient than multi-step conventional column chromatography for the separation of anthocyanins.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.127-134
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• 1984

As a series of studies to clarify clonorchicidal substances in body surface mucus of some freshwater fishes, the substance in the epidermal mucus of Cyprinus carpio was isolated by silica gel column and thin layer chromatography and analysed for its chemical nature. Wormicidal trial was done in vitro, and the results obtained are summarized as follows: The mucus was extracted by ethyl ether and separated into 4 fractions by column chromatography using benzene as solvent. The second fraction with yellowish red colour among them showed the strongest clonorchicidal effect. The yellowish red fraction obtained by column chromatography was then fractionated into 6 spots by thin layer chromatography with petrol/ etherjchloroform (30/70, v/v), and the Rf. 0.714 spot among the 6 spots showed the strongest effect. The Rf. 0.714 spot was further fractionated into 6 spots by thin layer chromatography with benzene/acetone (90/10, vlv), and the Rf. 0.800 spot among the later 6 spots revealed the strongest effect. The Rf. 0.800 spot was chromatographed on column with benzene and 2 fractions were obtained. The second fraction of light brown colour represented the final purified fraction. By these Purification Procedures, clonorchicidal substance was Purified 15-fold with 0.035 yield from the mucus of C. carpio, and 10mg of the final fraction killed the cercaria in 26 min, the metacercaria in 115 min, and the adult in 443 min. Infra red and nuclear magnetic resonance spectrometric analysis of the purified substance revealed that the substance belongs to an ethyl ester of unsaturated fatty acid with 2 double bonds, 15 methylene groups and 1 methyl group.