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        검색결과 593

        101.
        2015.06 구독 인증기관 무료, 개인회원 유료
        In order to use as a new functional food material, we analyzed the chemical components including the organic compounds, minerals and Vitamin C of sorbus and acacia honey which were produced in South Korea. The condensed rate of methanol extraction in honey was 77% of sorbus honey and it was 93.06% of acacia honey. In the case of sorbus honey, main organic compounds that extract by organic solvents in GC-MS analysis were trichloromethane, propylcarbinol, cyclopentane, acetoxyethane, tetrasol, aziridine etc. and main aromatic compounds that extract by organic solvents in SPME analysis were Skelly solve, Benzaldehyde, Hyacinthin, Dodecanal, Lauraldehyde etc. Also, in occasion of acacia honey, main organic compounds were trichloromethan, Acetoxyethane, Hexanaphthene, acetidin etc. and main aromatic compounds were Hydrazomethan, Azulene, Cyclotrisiloxane, Hydrazine etc. Proximate composition was crude protein 0.54%, crude fat 0.44%, crude ash 0.25% in sorbus honey and crude protein 0.10%, crude fat 0.29%, crude ash 0.06% in acacia honey. Free sugar that analyze by HPLC was fructose 26.81%, glucose 20.42%, total sugars 47.23% in sorbus honey and fructose 48.52%, glucose 24.29%, total sugars 72.81% in acacia honey. Vitamin C was not detected in two sample honeys. Minerals by ICP analysis were detected total 18 kinds in sorbus honey, K 11.715 ppm>Na 7.857 ppm>Si 4.407 ppm>Ca 3.673 ppm etc. and total 22 kinds in acacia honey, Na 4.527 ppm>Si 3.420 ppm>K 3.091 ppm>Zn 1.482 ppm etc.
        4,000원
        102.
        2015.06 구독 인증기관 무료, 개인회원 유료
        In order to use as a new functional food material, we analyzed the chemical components including the organic compounds, minerals and vitamin C of canola honey which were produced in South Korea. The condensed rate of methanol extraction in honey was 90.5% and main organic compounds that extract by organic solvents in GC-MS analysis were propyl carbinol, cyclopentane, trichloromethane, vinegar naphtha and so on. Also, main aromatic compounds that extract by organic solvents in SPME analysis were diisooctyl adipate, furole, furaldehyde, cyclotetrasiloxane, trisulfide and many more. As proximate composition, crude ash content was lower than acacia honey (0.06%) and manuka honey (0.24%) by 0.01%, and crude protein was higher than acacia honey (0.10%) by 0.23%, but the crude fat of canola and manuka honey was lower content than acacia honey (0.44%) by 0.10%. Free sugar that analyze by HPLC consisted of fructose 44.11%, glucose 22.72%, and total sugars was 66.83%. Minerals by ICP analysis were detected total 15 kinds, Na 7.157 ppm>Ca 5.934 ppm>Si 4.049 ppm>K 1.443 ppm>Mg 1.218 ppm etc. Vitamin C was not detected.
        4,000원
        103.
        2015.05 구독 인증기관·개인회원 무료
        고분자 전해질 막의 성능을 개선하고자 사용된 대표적인 무기물인 solid acid가 첨가된 복합막의 경우 고온에서 높은 열안정성을 나타내며 친수성이 강해지는 장점을 나타내지만 물에 녹는 단점을 가지고 있다. 그러므로 본 연구에서는 phosphotungstic acid(PWA)의 이온전도성을 증가시키며 물에 용해되는 성질을 제거하기 위하여 실리카 입자를 sol-gel법을 이용하여 술폰산기와 아민그룹을 도입시킨 입자를 제조한 후 sulfonated poly(arylene ether sulfone)(SPAES)고분자에 첨가하여 복합막을 제조하였으며 특성평가가 이루어졌다.
        104.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        삼채의 잎과 뿌리로부터 휘발성 화합물과 아미노산을 분석하였다. 휘발성 향기성분은 Headspace GC-MS방법으로 분석하였다. 잎 조직으로부터 18종의 휘발성화합물이 검출되었고, 21종의 화합물은 뿌리조직으로부터 분석되었다. 주요 향기성분은 diallyl disulphide였고, 잎(27.9%)과 뿌리(17.41)에서 가장 많이 함유하고 있었다. 또 다른 주요 황화합물은 methyl 2-propenyl disulfide, dimethyl disulfide, methyl 1-propenyl disulfide과 methyl 2-propenyl trisulfide이 잎과 뿌리에 모두 함유하고 있었다. 전체 46종 화합물 중 가장 많이 함유하고 있는 물질군은 황화합물이었다. 황화합물은 엽조직에 6종, 뿌리조직에는 5종이 함유되어 있었다. 또한 유리아미노산과 polyphenol성 화합물은 잎과 뿌리 조직에서 분석하였다. 잎과 뿌리 조직에서 아미노산은 20종과 19종이 각각 검출되었다. 총아미노산의 함량은 잎에서 0.134 mg/g, 뿌리조직에서 0.105 mg/g 함유하고 있었다. 총 polyphenol성 화합물 함량은 잎에서 0.28 mg/g, 뿌리에서 1.08 mg/g 함유하고 있었다. 이 결과는 삼채의 이용과 효율적인 재배에 기초자료를 제공할 수 있다.
        4,000원
        105.
        2015.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Volatile organic compounds(VOCs) are harmful substances that contribute to stratospheric ozone depletion, tropospheric photochemical ozone formation, and carcinogenic human health effects. Worldwide, there are major concerns over the emission of VOCs. Any plans for pollution reduction and management should be established based on database of VOC emission and characteristics. In this paper, the status of VOCs by year, region, and industry were investigated, and then technologies for VOC emission control were introduced. The estimation of VOC emissions by year was gradually increased, and VOC emission due to the utilization of organic solvents was the most common form. VOCs in the atmosphere were detected at the highest concentration in industrial complexes. In most of the industry, it was confirmed that emissions of toluene were the highest among the VOCs. Finally, available VOCs control technologies were introduced, including thermal and catalytic oxidation, adsorption, absorption, biological treatment, non-thermal plasma, electron beam irradiation, and photocatalyst.
        4,200원
        106.
        2015.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The porous Mg3Sb2 based compounds with 60~70% of relative density were prepared by powder compaction at room temperature and reactive liquid phase sintering at 1023 K for 4hrs. The stoichiometric Mg3Sb2 compounds were synthesized from elemental Sb and Mg powder in the mixing range of 61~63 at% Mg. The increased scattering effect due to the micro-pores reduced the mobility of the charge carrier and the phonon, which caused the electrical conductivity and the thermal conductivity to decrease, respectively. But the scattering effect was greater for the electrical conductivity than for the thermal conductivity. Excess Mg alloyed in the Mg3Sb2 compounds decreased the electrical conductivity, but had no effect on the thermal conductivity. On the other hand, the large increase of the Seebeck coefficient was the result of a decrease in the charge carrier density due to the excess Mg. Dimensionless figure of merit of the porous Mg3Sb2 compound reached a maximum value of 0.28 at 61 at% Mg. The obtained value was similar to that of Mg3Sb2 compounds having little pores.
        4,000원
        107.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Landfills are nettlesome sources of malodorous gases as well as methane that has the second largest radiative forcing of long residence-greenhouse gases, followed carbon dioxide. Because methane and malodorous gases are simultaneously emitted in landfills, investigation of whether or not methane and malodorous gases affect each other’s degradation is important. Amines such as monomethylamine(MMA), dimethylamine(DMA) and trimethylamine(TMA) are representative malodorous gases from landfills. In this study, the effect of amines on the bio-oxidation of methane was evaluated using a methane-oxidizing consortium where the dominant bacteria were Methylocystis spp. Amines inhibited the methane oxidation by the consortium, and the inhibition effect increased in the order of TMA > DMA > MMA. Methane oxidation rates in the consortium decreased with increasing amine/methane ratio(mol/mol). These results can be used to design and optimize the biological processes for simultaneous removal of methane and malodorous gases.
        4,000원
        108.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Volatile organic compounds(VOCs) detected frequently in the indoor air of child-care centers causes neurological disorders, lung, eyes, and bronchial irritation, and acute and chronic toxicity. In this study, the distributions of carcinogenic VOCs detected in child-care centers were characterized and a health risk assessment of the VOCs was performed, which can provide the necessary information for drawing up safety plans with respect to the concerned materials. The sampling of sites in day-care centers was undertaken two times: in the morning (10:00~12:00), and afternoon(16:00~20:00)-at 23 daycare centers located in Seoul, Korea from April, 2012 to July, 2012. The overall average concentrations of individual VOCs were benzene(1.61 μg/m3) > carbon tetrachloride (0.78 μg/m3) > chloroform(0.67 μg/m3) in order. Indoor/outdoor(I/O) ratios of benzene, carbon tetrachloride, chloroform were 1.33, 1.09, 1.72, respectively. Benzene and carbon tetrachloride are thought to be more strongly associated with outdoor sources as compared to chloroform. Spearman correlation of benzene, carbon tetrachloride between indoor and outdoor concentration showed statistically significant levels(p < 0.05). The linear correlations for benzene, styrene, and carbon tetrachloride were tested. A significant correlation was observed only for carbon tetrachloride, accounting for 83 % of the variance. The risk assessment of the carcinogenic VOCs for teachers, infants, and children showed that none of the targeted VOCs posed a serious risk.
        4,000원
        109.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objectives of this study were to characterize the factors affecting exposure to the VOCs and NO2 in the vicinity of Gwangyang industrial complex. The VOCs and NO2 levels were measured for residents of an exposure group (industrial area within 5 km) and a control group (15 km farther), respectively using the VOCs and NO2 filter badge as a passive sampler from August to September 2006. The means of indoor, outdoor, workplace and personal exposure levels of benzene were 1.10 ppb, 0.94 ppb, 1.85 ppb and 2.35 ppb respectively in the exposure group. The means regarding toluene for the exposure group were 9.29 ppb indoor, 8.09 ppb outdoor, 14.5 ppb workplace, 14.2 ppb personal exposure. The means regarding ethylbenzene were 4.96 ppb(indoor), 4.45 ppb(outdoor), 6.84 ppb (workplace), 6.10 ppb(personal exposure), and the means regarding xylene were 0.10 ppb(indoor, outdoor), 0.18 ppb(workplace) 0.17 ppb(personal exposure). The means for the indoor, outdoor, workplace and personal exposure level of NO2 were 18.40 ppb, 18.51 ppb, 18.59 ppb, 18.80 ppb respectively in the exposure group. Correlations between personal exposures and workplace concentrations of individual VOCs and NO2 exposures, and each of the microenvironment was statistically significant.
        4,000원
        110.
        2014.12 구독 인증기관 무료, 개인회원 유료
        In order to use as a new functional food material, we analyzed the chemical components including the organic compounds, minerals and Vitamin C of cherry and acacia honey which were produced in South Korea. The condensed rate of methanol extraction in honey was 87.51% of cherry honey and it was 93.06% of acacia honey. In the case of cherry honey, main organic compounds that extract by organic solvents in GCMS analysis were trichloromethane, propylcarbinol, methacide, cyclopentane, tetrafinol etc. and main aromatic compounds that extract by organic solvents in SPME analysis were formyl trichloride, propanal, furfurylaldehyde, pyrazole, benzenecarbonal etc. Also, in occasion of acacia honey, main organic compounds were trichloromethan, Acetoxyethane, Hexanaphthene, acetidin etc. and main aromatic compounds were Hydrazomethan, Azulene, Cyclotrisiloxane, Hydrazine etc. Proximate composition was crude protein 0.33%, crude fat 0.15%, crude ash 0.47% in cherry honey and crude protein 0.10%, crude fat 0.44%, crude ash 0.06% in acacia honey. Free sugar that analyze by HPLC was fructose 37.05%, glucose 27.29%, total sugars 64.34% in cherry honey and fructose 48.52%, glucose 24.29%, total sugars 72.81% in acacia honey. Vitamin C was not detected in two sample honeys. Minerals by ICP analysis were detected total 25 kinds in cherry honey, K 9.762 ppm¤Si 5.628 ppm ¤Na 5.096 ppm¤Ca 2.224 ppm etc. and total 22 kinds in sacacia honey, Na 4.527 ppm¤Si 3.420 ppm¤K 3.091 ppm¤Zn 1.482 ppm etc.
        4,200원
        115.
        2014.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Due to their unique properties, tungsten borides are good candidates for the industrial applications where certain features such as high hardness, chemical inertness, resistance to high temperatures, thermal shock and corrosion. In this study, conditions were investigated for producing tungsten boride powder from tungsten oxide(WO3) by self-propagating high-temperature synthesis (SHS) followed by HCl leaching techniques. In the first stage of the study, the exothermicity of the WO3-Mg reaction was investigated by computer simulation. Based on the simulation experimental study was conducted and the SHS products consisting of borides and other compounds were obtained starting with different initial molar ratios of WO3, Mg and B2O3. It was found that WO3, Mg and B2O3 reaction system produced high combustion temperature and radical reaction so that diffusion between W and B was not properly occurred. Addition of NaCl and replacement of B2O3 with B successfully solved the diffusion problem. From the optimum condition tungsten boride(W2B and WB) powders which has 0.1~0.9 um particle size were synthesized.
        4,000원
        117.
        2014.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates the chemical compositions of Aster koraiensis Nakai essential oils and the quantitative changes of major terpene compounds according to various harvesting times. The essential oils obtained by hydrodistillation from the aerial parts of Aster koraiensis Nakai are being analyzed by GC and GC-MS. The essential oil compositions of Aster koraiensis Nakai are characterized byhigher contents of sesquiterpene compounds. Ninety-seven volatile flavor compounds are being identified in the essential oils from Aster koraiensis Nakai harvested in 2010, and caryophyllene oxide (8.38%), aristolene (7.08%), epiglobulol (5.57%), and ethyl furanone (4.73%) are the most abundant compounds. Ninety-five compounds are identified in the essential oils from the plants harvested in 2011, and aristolene (11.56%), calarene (9.33%), phytol (8.28%), ethyl furanone (7.63%), and epiglobulol (7.18%) are the most abundant compounds. Ninety-five compounds are being identified in the essential oils from the plants harvested in 2012, and calarene (15.3%), aristolene (14.24%), ethyl furanone (7.21%), phytol (6.98%) are the major compounds. The contents of aristolene, α-caryophyllene, α-muurolene, α-calacorene, aromadendrene oxide, and calarene increase significantly from 2010 to 2012. The contents of α-cubebene, isocaryophyllene, and diepi-α-cedrene epoxide decrease significantly from 2010 to 2012. The quantitative changes of aristolene and calarene according to harvesting time can be served as a quality index of the Aster koraiensis Nakai essential oils.
        4,000원
        119.
        2013.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The children of daycare center are sensitive to indoor environmental pollution. This study was a preliminary investigation for improving the environmental and healthy quality of daycare centers. The sampling of sites in daycare centers was undertaken three times such as day-morning (10:00-12:00), afternoon (16:00-20:00), following dawn (04:00-08:00)-at 21 daycare centers located in Seoul, Korea from April, 2012 to July, 2012. The mean concentrations of TVOC were 255.2, 217.0, and 439.4 μg/m3 at morning, afternoon, and following dawn, respectively. The daycare center indoor/outdoor ratios on the most targeted volatile organic compounds were above 1.0 except that for carbon tetrachloride, which was almost 1.0. Significant correlations (p<0.01) were observed between indoor and outdoor carbon tetrachloride, which implies that indoor carbon tetrachloride could be largely accounted for by outdoor sources. The other targeted indoor volatile organic compounds such as benzene, toluene, ethylbenzene, styrene, xylenes, chloroform showed no significant correlations with that of outdoor.
        4,600원
        120.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was investigated the chemical composition from Syneilesis palmata essential oil and the tendency of variation of the sesquiterpene compounds according to the harvesting time. The essential oils obtained by hydro distillation from the aerial parts of Syneilesis palmata were analyzed by GC and GC-MS. Ninety-eight compounds consisting of 9 aliphatic hydrocarbons, 17 sesquiterpene hydrocarbons, 11 aliphatic aldehydes, 1 terpene aldehyde, 8 aliphatic alcohols, 4 monoterpene alcohols, 16 sesquiterpene alcohols, 3 diterpene alcohols, 6 ketones, 11 esters, 8 oxides and epoxides, 3 acids and 1 miscellaneous one were identified from the oil. Spathulenol (22.33%) was the most abundant compound, followed by β- caryophyllene (6.23%), germacrene D (5.57%), longipinane (4.10%), and epiglobulol (3.65%). The volatile composition of Syneilesis palmata was characterized by higher contents of sesquiterpene compounds, especially sesquiterpene alcohols. The total content of 13 sesquiterpene compounds was decreased significantly from 2010 to 2012. α-Caryophyllene, β-bisabolene, elemol, germacrene D, β-zingiberene, longipinane, and β-caryophyllene alcohol contents decreased, while β-bisabolol content increased during 3 years. The ecological responses to recent climate change may be influenced in the chemical components of natural plant terpenoids.
        4,000원