• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.177-177
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• 2003

• Journal of Astronomy and Space Sciences
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• 제15권1호
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• pp.163-174
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• 1998

To study the origin of organic matter in meteorite, terrestrial rocks which contain or-ganic compounds similar to the ones found in carbonaceous chondrites are studied and compared with Muchison meteorite. Hydrocarbon molecules were extracted by benzene and methanol from bituminous coal and oil shale and the extracts were partitioned into aliphatic, aromatic, and polar fractions by silica gel column chromatography. Carbon isotopic ratios in each fractions were analysed by GC-C-IRMS. Molec-ular compound identifications were carried by GC-MS Engine. Bituminous coal and oil shale show the organic compound composition similar to that of meteorite. Oil shale has a wide range of ${\delta}^{13}C,-20.1%_0~-54.4%_0$ compared to bituminous coal, $-25.2%_0~34.3%_0$. Delta values of several molecular compounds in two terrestrial samples are different. They show several distinct distributions in isotopic ratios compared to those of meteorite; Murchison meteorite has a range of ${\delta}^13C\;from\;-13%_0\;to\;+30%_0$. These results provide interpretation for the source and the formation condition of each rock, in particular alteration and migration processes of organic matter. Especially, they show an important clue whether some hydrocarbon molecules observed in meteorite are indigenous or not.

• 대한화학회지
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• 제11권2호
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• pp.45-50
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• 1967

有機할로겐化合物의 分離方法으로써 試料의 中性子照射에 依한 放射化 Thin Layer Chromatography를 Methanol을 展開溶媒로 하여 硏究한 結果 各種 할라이드, 할로겐酸, 할로겐알데하이드 等에서 銳敏한 展開 peak를 얻었으며 混合物의 展開에서도 定性確認에 充分한 分離 peak를 얻었다. 多 할로겐化合物, 芳香核鹽化物에 있어서는 試料의 中性子線 照射에 依하여 한 個 以上의 放射化할로겐化合物이 生成되어 確認이 困難하였으며 其他 할로겐 化合物에서는 再現性있는 Rf値를 얻을 수 있었다. 그리고 實驗方法을 記述하고 本 方法의 有用性에 關하여 論議하였다.

• 한국환경과학회지
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• 제21권2호
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• pp.165-179
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• 2012

Indirect $CO_2$ effect due to non-methane volatile organic compound (NMVOC) emissions from solvent and product use and fugitive NMVOC emissions from fuels in the Republic of Korea and 13 Annex I countries under United Nations Framework on Climate Change were estimated and the proportions of them to total greenhouse gas (GHG) emissions ranged from 0.092% to 0.45% in 2006. Indirect greenhouse effect ($CO_2$, $CH_4$, and $O_3$) were estimated at 13 photochemical assessment monitoring sites in the Republic of Korea using concentrations of 8 NMVOCs of which indirect global warming potential (GWP) were available. The contribution of toluene to mixing ratio was highest at 11 sites and however, the contribution of toluene to indirect greenhouse effect was highest at nine sites. In contrast to toluene, the contributions of ethane, butane, and ethylene were enhanced. The indirect greenhouse effects of ethane and propane, of which ozone formation potentials are the lowest and the third lowest respectively among targeted 10 NMVOCs, ranked first and fourth highest respectively. Acetaldehyde has relatively higher maximum incremental reactivity and is classified as probable human carcinogen however, its indirect GWP ranked second lowest.

• 센서학회지
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• 제17권1호
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• pp.69-74
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• 2008

VOCs (Volatile Organic Compound) sensors were fabricated using $SnO_2$nanowires-based thin films and its gas sensing behaviors were studied. The $SnO_2$ nanowires synthesized from a thermal evaporation process were dispersed in a solution and the sensor film was prepared by dropping the slurry on the substrate with the electrodes and an embedded heater. The gas response (Ra/Rg, Ra: resistance in air, Rg: resistance in gas) to $30{\sim}40$ ppm Benzene, Ethyl Benzene, o-xylene were in the range of $39{\sim}42$, which were significantly higher than those to 50 ppm of CO, $CH_4$ and $C_3H_8$ ($12{\sim}19$).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.425.2-425.2
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• 2014

$TiO_2$ possesses great photocatalytic properties but absorbs only UV light owing to high band gap energy (Eg = 3.2 eV). By narrowing the band gap through doping a metal ion, the photocatalytic activity can be enhanced in condition of the light of a higher than 365 nm wavelength. Main purpose for this study is to evaluate the activities of metal doped $TiO_2$ for degrading the volatile organic compounds (VOCs); p-xylene is chosen in the VOC removal test. Vanadium is selected in this study because an ionic radius of vanadium is almost the same as titanium ion and vanadium can be easily doped into $TiO_2$. V-doped $TiO_2$ was synthesized by sol-gel methods and compared with pure $TiO_2$. Pure TiO2 powder and V-doped $TiO_2$ powder were coated on glasses by spray coating method. UV-Visible spectrophotometer was used for the measurement of the band gap changes. VOC concentration degradation level was tested with using various UV light sources in an enclosed chamber. Catalytic activities of prepared samples were evaluated based on the experimental results and compared with coated pure $TiO_2$ sample.

• 한국대기환경학회지
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• 제27권6호
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• pp.751-771
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• 2011

Biogenic Volatile Organic Compound (BVOC) emissions are estimated with BEIS3.12 (Biogenic Emissions Inventory System version 3.12) over the Seoul Metropolitan Area (SMA) and then used in CMAQ (Community Multiscale Air Quality) simulations for two high ozone episodes in 2004 and 2007 June. The first- and second-order sensitivity coefficients of ozone to BVOC emissions are estimated with High-order Decoupled Direct Method (HDDM) simulation in order to estimate the influence of BVOC emissions on ozone using the Zero-Out Contribution (ZOC) approach. ZOC analysis shows that relative contribution of BVOC emissions on daily maximum 1-hr ozone is as high as 30% for high ozone days above 100 ppb. However simulated isoprene concentrations were over-estimated by a factor of 2 when compared to the observations at the PAMS (Photochemical Air Monitoring Station) for the 2007 episode. When assumed that actual BVOC emissions are 50% less than estimated, the ZOC of BVOC emissions on daily maximum ozone drops by more than 10 ppb for the episode. The result indicates that uncertainty in BVOC emissions may have significant impact on high ozone prediction in the SMA.

• 한국화재소방학회논문지
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• 제14권3호
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• pp.19-26
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• 2000

화학물질의 기본적인 물리적 특성으로서 인화점은 화학물질에 의한 재난방제에 있어서 중요한 인자 중에 하나이다. 많은 혼합물에 대한 체계적 자료는 매우 빈약하여 이들 물질에 대한 인화점 측정은 어렵다. 따라서 화학적으로 합성과정에 있는 물질 뿐 만 아니라 현재 제품으로 사용하고 있는 물질의 물리화학적 특성을 모두 실험에 의하여 구하는 것은 현실적으로 곤란하다. 본 연구의 관심은 화학적 구조와 인화점 사이에 관계를 이용한 유기개념도를 이용하여 화학적 구조만으로 화차물의 인화점을 대략적으로 예측하는 방법을 시도하고자 하였다.

• International Journal of Industrial Entomology and Biomaterials
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• 제48권2호
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• pp.67-77
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• 2024

This study aims to assess the efficacies of exogenous enzymes, derived from invertebrate gut-associated microbes, as feed additives, in reducing volatile organic compound (VOC) emissions using an in vitro pig intestine continuous fermentation system. An in vitro continuous fermentation model was used to simulate a comparable bionic digestion system by co-reacting feed, enzymatic additives (arazyme, mannanase, and xylanase, derived from the gut bacteria of Nephila clavata, Eisenia fetida, and Moechotypa diphysis, respectively), and gastrointestinal microbes, followed by an analysis of their correlations. A significant correlation was observed between exogenous enzyme supplementation and reduced VOC emissions in the fecal phase of continuous fermentation (p < 0.05). The concentration of VOCs decreased by 3.75 and 2.75 ppm in the treatment group following arazyme and multi-enzyme supplementation, respectively, compared to that in the control group (7.83 ppm). In addition, supplementation with arazyme and multiple enzymes significantly affected the microbial composition of each fermentation phase (p < 0.05). In particular, Lactiplantibacillus pentosus and Pediococcus pentosaceus, which changed in abundance according to arazyme or multi-enzyme supplementation, exhibited a positive relationship with VOC emissions. These results suggest that exogenous enzymes derived from invertebrate gut-associated bacteria can be efficiently applied as feed additives, leading to a reduction in VOC emissions.

• Bulletin of the Korean Chemical Society
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• 제22권6호
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• pp.611-615
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• 2001

A new polynuclear complex of manganese stearate has been prepared by substitution of acetate with stearic acid. The stearate ion with long alkyl chain was used to isolate molecular $Mn_{12}$ cluster from each other. The $Mn_{12}$-stearate compound prepared is soluble in most organic solvents and resistant against water catalyzed reduction. The $Mn_{12}$-stearate compound shows similar electrochemical, magnetic properties to the pristine $Mn_{12}$-acetate.