• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.1
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• pp.51-55
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• 2016

Organofluorine compounds have become increasingly important as pharmaceuticals, radiopharmaceuticals, agrochemicals, and material science. Recent advances on the efficient introduction of fluorine to organic molecules are mainly results of development of transition metal catalysts and fluorination reagents. Among the various fluorination reagents, we have been interested in developing more efficient sulfur-based deoxyfluorinating reagents. Here we report various electronic properties of five popular sulfur-based deoxyfluorinating reagents using density functional theory calculation. We believe that the theoretical study on the reagents will assist the rational design of new deoxyfluorinating reagents.

• Environmental Analysis Health and Toxicology
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• v.17 no.3
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• pp.207-217
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• 2002

This study was designed to investigate the characteristics of atmospheric concentrations of toxic volatile organic compounds (VOCs) in Korea. Target compounds included 1,3-butadiene, aromatics such as BTEX, and a number of carbonyl compounds. In this paper, as the second part of the study, the seasonal and locational concentrations of atmospheric VOCs were evaluated. Sampling was conducted seasonally at seven sampling sites. each of them representing a large urban area (commercial and residential), a small urban area (commercial and residential), an industrial area (a site within the complex and a residential), and a background place in Korea. In general, higher concentrations were found in the petro-chemical industrial site than other sites, while VOCs measured in commercial (heavy -traffic) sites were higher than residential sites. Seasonality of VOCs concentrations were not so much clear as other combustion related pollutants such as sulfur dioxide, indicating that the VOCs are emitted from a variety of sources, not only vehicle exhaust and point sources but fugitive emissions. Except the industrial site, the concentrations of VOCs measured in this study do not reveal any serious pollution status, since the levels did not exceed any existing ambient standards in the U.K. and/or Japan. However, the increasing number of petrol -powered vehicles and the rapid industrialization in Korea may result in the increased levels of VOCs concentrations in many large urban areas in the near future, if there is no appropriate programme implemented for the control of these compounds.

• Journal of Life Science
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• v.20 no.1
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• pp.60-65
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• 2010

Since organic sulfur compounds respond to GC/ECD sensitively, they interfere with quantitative separation of pesticides during residual pesticide analysis of Allium species. In this study, it was intended to develop a rapid and simple method for pesticide multi-residues analysis through clean-up and interferences by a solid-phase extraction (SPE). An SPE method employing silver nitrate impregnated Florosil cartridge was developed and evaluated for the elimination of sulfur compounds from the test solution of Allium species during pesticide residues analysis. The silver nitrate impregnated Florosil cartridge was prepared by efflux of 3 ml of 20% silver nitrate solution through Florosil cartridge (1 g packing, 6 ml tube). The extracts equivalent to 2, 4 6, and 10 g of each sample were loaded onto the cartridge and allowed to exude, and then the exudations were analyzed by GC/ECD. More than 95% of sulfur compounds were removed from the loaded extracts equivalent, up to 6 g in onion, 4 g in spring onion and 4 g in shallot, respectively. 40 pesticides were spiked in the Allium species and loaded onto the cartridge to determine the recoveries; from this, the recoveries of 34 pesticides were within 70~120%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.543-545
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• 2002

The volatile compounds in kimchi adsorbed with solid phase microextraction (SPM) were analyzed by using a gas chromatograph-atomic emission detector (GC-AED) and a gas chromatograph-mass spectrometer (GC-MSD). The volatile compounds were effectively adsorbed in SPME. Twenty five compounds such as dimethyl-sulfide were identified by GC-MSD and some of these were further confirmed to contain a sulfur and a nitrogen by GC-AED.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.1
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• pp.39-49
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• 2007

In this study, the performance characteristics of solid phase microextraction (SPME) were investigated for three major odorous groups that consist of 10 individual compounds ([1] volatile organic compounds (VOC): benzene, toluene, p-xylene and styrene, [2] reduced sulfur compounds (RSC): hydrogen sulfide, methyl mercaptan, dimethylsulfide (DMS), dimethyldisulfide (DMDS), and carbon disulfide, and [3] amine: trimethylamine (TMA)). For the purpose of a comparative analysis, two types of SPME fiber ([1] polidimethylsiloxane/divinilbenzene (P/D) and [2] $Carboxen^{TM}$/polidimethylsiloxane (C/P)) were test ε d against each other for a series of standards prepared at different concentration levels (100, 200, and 500 ppb). To compare the analytical performance of each fiber, all standards were analyzed for the acquisition of calibration data sets for each compound. The results of P/D fiber generally showed that its calibration slope increased as a function of molecular weight across different VOCs; however, those of C/P fiber showed a fairly reversed trend. Besides, we confirmed that the application of SPME is limited to many sulfur compounds; only two compounds (DMS and DMDS) are sensitive enough to draw calibration results out of SPME. The calibration data for RSC show generally enhanced slop values for C/P relative to P/D fiber. However, in the case of TMA, we were not able to find a notable difference in their performance.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.6
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• pp.15-20
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• 2012

The effects of sulfur dioxide on paper were investigated since these sulfur compounds could cause damages on cellulose and organic materials in papers. For the reason, exposure ageing tests were performed on traditional Korean paper (Hanji) and two different types of modern paper (acid-free and acid paper) to determine the damage with regard to the optical as well as physicochemical properties according to the varying $SO_2$ concentration. As a result, optical properties were not changed while physical and chemical peoperties were remarkably changed with the exposure period. In the case of pH, $SO_2$ had little impact on the pH of the Hanji and acid-free paper while the pH of acid paper was remarkably decreased. The decrease of the folding endurance of the Hanji was relatively smaller than those of the acid-free and acid paper. The results prove Hanji was more resistant to $SO_2$ than the modern paper in terms of optical, physical and chemical properties. In addition, it was also suggested that $SO_2$ concentration should be kept below 0.01 ppm for the preservation of paper objects.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.975-978
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• 2008

Novel sulfur-containing aromatic compounds were developed as stable, high-performance organic semiconductors for OTFT applications. Of them, dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) consisting of six aromatic rings gave high quality thin films by vapor deposition, which acted as a superior FET channel showing FET mobility as high as $3.0\;cm^2V^{-1}s^{-1}$. On the other hand, highly soluble 2,7-dialkyl[1]benzothieno[3,2-b][1]benzothiophenes ($C_n$-BTBTs) gave solution-processible OTFTs with FET mobility higher than $1.0\;cm^2V^{-1}s^{-1}$.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.4
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• pp.118-126
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• 2012

In this study, two types of ozone generating experimental instrument were installed in commercial livestock manure fertilization facility, which can treat hundred tons of pig manure in a day. Gas samples to be treated were collected from the upper part of the liquid fertilization system and composting system of the commercial livestock manure fertilization facility. The gas sample was flowed to oxidation reactor through pipe line by suction blower, therefore, contacted with ozone. Ammonia and sulfur compounds of gas samples collected from the inlet and outlet point of the experimental instrument were analyzed. The oxidation effect by the contact with ozone was higher in sulfur compounds than ammonia. Ammonia content was reduced about 10% by ozone contact. Sulfur compounds, on the other hand, reduced significantly while treated with ozone. In case of gas sample collected from liquid fertilization system, the concentrations of hydrogen sulfide ($H_2S$), methyl mercaptan (MM), dimethyl sulfide (DMS), and dimethyl disulfide (DMDS) of inlet gas were 50.091, 4.9089, 27.8109 and 0.4683 ppvs, respectively. After oxidized by ozone, the concentrations of sulfur compounds were 1.2317, 0.3839, 14.7279 and 0.3145 ppvs, respectively. Another sample collected from aerobic composting system was oxidized in the same conditions. The concentrations of $H_2S$, MM, DMS and DMDS of the sample collected from inlet point of the reactor were 40.6682, 1.3675, 24.2458 and 0.8289 ppvs, respectively. After oxidized, the concentrations of $H_2S$, MM, DMS, and DMDS were reduced to 3.013, ND, 8.8998 and 0.3651 ppvs, respectively. By application of another type of ozone, the concentrations of $H_2S$, MM, DMS and DMDS of inlet gas were reduced from 43.397, 1.4559, 3.6021 and 0.4061 to ND, ND, ND, and 0.21ppvs, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.46-52
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• 2007

As flue gas desulfurization (FGD) wastewater contains high concentrations of nitrate and is very low in organic carbon, the feasibility of nitrate removal by autotrophic denitrification using Thiobacillus denitrificans was studied. This autotrophic bacteria oxidizes elemental sulfur to sulfate while reducing nitrate to elemental nitrogen gas, thereby eliminating the need for addition of organic compounds such as methanol. Owing to the unusually high concentrations of dissolved salts $(Ca^{2+},\;Mg^{2+},\;Na^+,\;K^+,\;B^+,\;SO_4^{2-},\;Cl^-,\;F^-,)$ in the FGD wastewater, extensive laboratory-scale and pilot-scale tests were carried out in sulfur-limestone reactors (1) to determine the effect of salinity on autotrophic denitrification, (2) to evaluate the use of limestone for pH control and as source of inorganic carbon for microbial growth, and, (3) to find the optimum environmental and operational conditions for autotrophic denitrification of FGD wastewater. The experimental results demonstrated that (1) autotrophic denitrification is not inhibited up to 1.8 mol total dissolved salt content; (2) inorganic carbon and inorganic phosphorus must be present in sufficiently high concentrations; (3) limestone can supply effective buffering capacity and inorganic carbon; (4) the high calcium concentration may interfere with pH control, phosphorus solubility and limestone dissolution, hence requiring pretreatment of the FGD wastewater; and, 5) under optimum conditions, complete autotrophic denitrification of FGD wastewater was obtained in a sulfur-limestone packed bed reactor with a sulfur:limestone volume ratio of 2:1 for volumetric loading rates up to 400g $NO_{3^-}N/m^3.d$. The interesting interactions between autotrophic denitrification, pH, alkalinity, and the unusually high calcium and boron content of the FGD wastewater are highlighted. The engineering significance of the results is discussed.

• Bulletin of the Korean Chemical Society
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• v.10 no.1
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• pp.75-80
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• 1989

The approximate rates and stoichiometry of the reaction of excess potassium 9-sec-amyl-9-boratabicylco[3.3.1]nonane (K 9-sec-Am-9-BBNH) with selected organic compounds containing representative functional goups under standardized conditions (tetrahydrofuran, $0^{\circ}C)$ were examined in order to explore the reducing characteristics of the reagent for selective reductions. The reagent readily reduces aldehydes, ketones, acid chlorides and epoxides to the corresponding alcohols. However, carboxylic acid, aliphatic nitriles, t-amides, and some sulfur compounds show very little reactivity or no reactivity to this reagent. The most interesting feature of the reagent is that aromatic nitriles are reduced moderately to the corresponding aldehyde stage, wheras aliphatic nitriles are inert. In addition, the reagent shows a high stereoselectivity toward cyclic ketones at $0^{\circ}C$ and - $25^{\circ}C.$ The selectivity exhibited at $0^{\circ}C$ is comparable to that by lithium trisiamylborohydride at that temperature.