• 한국환경보건학회지
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• 제29권4호
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• pp.10-16
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• 2003

Atmospheric samples were conducted from September 2001 to July 2002 with GPS-l PUF sampler in rural site to concentration distributions of gas/particle PCBs and to calculate dry deposition flux of PCBs. $\Sigma$PCBs concentrations of gas/particle PCBs were 59.29$\pm$48.83, 6.56$\pm$6.59 pg/㎥, respectively. Gas contribution (%) of total PCBs (gas + particle) was 90% which existed gas phase in the atmosphere. The particle contribution (%) of PCB congeners increased relatively more of the less volatile congeners with the highest chlorine number. The correlation coefficients (r) between total PCBs and temperature ($^{\circ}C$) showed negative correlation in - 0.62 (p<0.0l) for particle phase, positive correlation in 0.63 (p<0.01) for gas phase. In other word, particle phase PCBs is enriched in colder weather which could be due to greater in corporation of condensed gas phase at low temperature. The calculated dry deposition of total PCBs (gas + particle) was 0.008, 0.008 $\mu\textrm{g}$ $m^{-2}$ da $y^{-l}$ which showed maximum dry deposition flux in December, minimum data in July Bs in the atmosphere. The calculated dry deposition fluxes of total PCBs were influenced by particle phase PCBs even though PCBs in the atmosphere were present primarily in the gas phase.e.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1489-1494
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• 2004

A gas chromatography/mass spectrometric assay method was developed for the determination of persistent organochlorine pollutants (POPs) in hair. For the exact extraction study was used hair of rat exposed with POPs. Sonication of the hair matrix with 3 M HCl solution in methylene chloride of the extraction methods studied was the most efficient and rapid sample preparation method. After sonication of rat hair was achieved clean up with a solid phase extraction procedure using silica gel-florisil. Elution was performed with 8 mL of methylene chloride. The eluate was concentrated to approximately 100 ${\mu}L$ and analyzed by gas chromatography-mass spectrometry (GC-MS). Detection limits of POPs were in the concentration range of 0.6-1.2 ng/g in rat hair. Aldrin, dieldrin, p,p-DDT and mirex were dosed rat for 4 weeks at concentration of 0.01 mg/L in drinking water and detected in rat hair at concentration of 2.8, 11.3, 7.9 and 15.6 ng/g, respectively. Aldrin and p,p-DDT were metabolized to dieldrin and p,p-DDE, which were detected in concentration of 9.7 and 2.9 ng/g in rat hair, respectively. The developed method may be valuable to be used to analyze POPs in human hair.

• 약학회지
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• 제16권1호
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• pp.55-64
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• 1972

The determination method of l-ephedrine and dl-methylephedrine by gas chromatography was developed, using reactive alkaline precolumn packed with celite 545 containing KOH. Symmetrical peaks were achieved under the condition, inlet temperature, $180^{\circ}C$-$230^{\circ}C$; column temperature, $180^{\circ}C$- $160^{\circ}C$; carrier gas flow rate, 30ml/minute. The peaks of the salts coincided with those of bases. When this method was applied to preparations, using d-dimethylaminobenzaldehyde as inner standard, good results were obtained. The relative retention times of l-ephedrine and dl-methylephedrine to p-dimethyl aminobenzaldehyde were 0.50 and 0.65 respectively.

• 한국미생물·생명공학회지
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• 제27권1호
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• pp.62-69
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• 1999

Clostridium butyricum NCIB 9576 evolved hydrogen gas and produced various organic acids from glucose, lactose, starch, and glycerol. Total amount of hydrogen gas produced from 1 and 2% glucose were 630 and 950ml $H_2$/l-broth, respectively, for the first 24 hrs of incubation and the maximum hydrogen production rates were 42 and 94ml $H_2$/hr/1-broth, respectively. Teh initial pH 6.8 decreased to 4.2~4.5 during the first 12~16 hrs of fermentation when the pH was not controlled, resulting in ceasing the cell growth and hydrogen evolution and in degradation of 82 and 40% glucose after 24hrs of incubation from 1 and 2% glucose, respectively. When pH was controlled to 5.5, glucose was consumed completely and resulted in increasing hydrogen production approximately 38~50% compared to the experiments without the pH control. C. butyricum NCIB 9576 produced hydrogen gas approximately 644, 1,700 and 3,080 ml $H_2$/l-broth with 0.5, 1 and 2% lactose, respectively and the maximum hydrogen production rates were 41, 141 and 179ml $H_2$/hr/l-broth, respectively. All of the lactose added was degraded completely during fermentation even though pH was not controlled. C. butyricum NCIB 9576 produced 183 and 709ml $H_2$/l-broth with 0.1 and 0.5% starch for 48 hrs, respectively, when pH was not controlled. The maximum rates of hydrogen gas production were 43 and 186ml $H_2$/l-broth, respectively and 80~100% of starch added was fermented. Approximately 107ml $H_2$/l-broth was produced using 1% glycerol by C. butyricum NCIB 9576 and the pH was maintained higher than 6.1 during fermentation without pH control. The degradation of glucose, lactose, starch and glycerol by C. butyricum NCIB 9576 were affected by the pH of fermentation broth and the organic acids released during fermentation. The pH of feremtntation broth dropped to 4.2~4.6 after 12~14 hrs incubation when glucose was used as a substrate while pHs were maintained above pH 5 under the same experimental conditions when lactose, starch and glycerol were used. The organic solvents and acids produced during glucose fermentation were mainly ethanol, butyrate, acetate and a little of propionate, while butyrate was the main organic acids during the lactose, starch, and glycerol fermentation by C. butyricum NCIB 9576.

• 한국미생물·생명공학회지
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• 제9권4호
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• pp.219-223
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• 1981

축산공해를 방지하고 대체에너지를 개발하기 위하여 가축분뇨로부터의 메탄가스 발효실험을 실시하여 다음의 결과를 얻었다. (1) 각 가축의 분뇨에 약 30%의 슬러지를 첨가하여 37$^{\circ}C$에서 20일간 발효시킨 결과 우분, 돈분 및 계분의 유기물 1 kg당 메탄가스 생성량은 각각 181, 248 및 235 $\ell$였으며 발효기간중 pH 변화는 발효 초기에 약간 저하하다가 점차 상승하는 경향을 보였다. (2) 우분(300g)과 물(200g)의 혼합물에 슬러지를 각각 20, 30, 40 (w/w) %씩 첨가하여 발효시킨 결과 가스생성량은 약 6.1, 14. 5, 13.4 $\ell$ 였다. (3) 우분에 톱밥과 왕겨를 각각 등량씩 혼합하여 발효시킨 결과 톱밥 첨가시가 왕겨 첨가시보다 메탄생성량이 많았다. (4) 메탄발효처리물의 N, K, P의 함량에 있어서 N, K의 함량은 계분>돈분>우분의 순서였고 P는 우분>계분>돈분의 순서였다. (5) 수중펌프발효조를 이용하여 우분으로부터 메탄가스 생산발효를 20일간 실시한 결과 유기물 1kg 당 188 $\ell$의 메탄가스가 생성되었고, 이 때 생성된 총 메탄가스의 가격과 소모된 전력요금과는 거의 비슷하였다.

• 한국자동차공학회논문집
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• 제18권4호
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• pp.127-131
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• 2010

Stainless steel sheets are widely used as the structural material for the railroad cars and the commercial vehicles. These kinds of structures used stainless steel sheets are commonly fabricated by using the gas welding. For fatigue design of gas welded joints such as fillet and plug type joint, it is necessary to obtain design information on stress distribution at the weldment as well as fatigue strength of gas welded joints. And also, the influence of the geometrical parameters of gas welded joints on stress distribution and fatigue strength must be evaluated. Thus, in this paper, ${\Delta}P-N_f$ curves were obtained by fatigue tests. Using these results, ${\Delta}P-N_f$ curves were rearranged in the. ${\Delta}{\sigma}-N_f$ relation with the hot spot stresses at the gas welded joints.

• 한국대기환경학회지
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• 제23권4호
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• pp.457-465
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• 2007

This study was performed to estimate the gas-particle partitioning of organochlorine pesticides (OCPs) in atmosphere, the samples were collected by PUF high volume air sampler for two years from June, 2000 to June, 2002. The gas phase fraction of ${\alpha/\gamma}-HCH$, heptachlor epoxide, ${\alpha/\gamma}-chlordane$ and trans-nonachlor was over 90%. But the gas phase fraction of ${\beta}-HCH$, p,p'-DDE, endosulfan sulfate, p,p'-DDD and p,p'-DDT was range of 20% through 80%, which means the gas phase fraction of OCPs components described above is sensitive to temperature. The correlation between the gas phase fraction and molecular weight of each OCPs component was not found in this research. The slope of regression line between gas-particle partitioning coefficient(${\log}K_p$) and subcooled liquid vapor(${\log}{P^o}_L$), gal-particle partitioning coefficient(${\log}K_p$) and octanol-air partitioning coefficient(${\log}K_{oa}$) which show -0.54 and 0.43 was not steep. So the equilibrium state between gas and particle was not reached and in this state the particulate fraction was low.

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.985-987
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• 2008

Parathion is an organophosphate pesticide being legally applied for the purpose of agriculture and is being manufactured in Korea. A gas chromatography/mass spectrometric method was developed for the determination of parathion urinary metabolite, p-nitrophenol. p-Nitrophenol was extracted from weak acidic urine, and then measured by gas chromatography-mass spectrometry (selected ion monitoring). The recovery of pnitrophenol in the overall procedure was 88.2%. The detection limit of the assay was 1.0 $\mu$ g/L based upon assayed urine of 2.0 mL. The method was applied to the determination of p-nitrophenol in urine of workers of a parathion industry. Spot urines of workers of a parathion industry were sampled at the end of shift and pnitrophenol was analyzed using above developed method. p-Nitrophenol could be detected in all of the urine samples at concentrations varying from 3.0 to 681 $\mu$ g/L.

• 한국대기환경학회지
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• 제21권3호
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• pp.285-293
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• 2005

This study was aimed at estimation of gas-particle partitioning of polychlorinated biphenyls (PCBs) in ambient air. The samples were collected at urban site in Japan from March 2002 to January 2003. The concentration of total PCBs (from 4 CB to 10 CB) and TEQ (Toxic equivalent) ranged from 62 to $247\;pg/m^3$ and from 2 to $14\;fgTEQ/m^3 $, respectively. The average contribution $(\%)$ of gas phase to total PCBs concentration was above $80\%$, which suggests that in the atmosphere PCBs predominantly existed in the gas phase. The weak correlations between total PCBs concentration and temperature was found. However this result was due to a typhoon during summer and raining during sampling period. The gas-particle partition coefficient (Kp) was obtained as a function of temperature. The partition ratio of gaseous and particulate phase PCBs can be estimated for an arbitrary temperature. The plot of gas/particle partition coefficient (log Kp) vs. sub-cooled liquid vapor pressure $(log\;P_L)$ had reasonable correlations for individual samples but the slope varied among the samples (coefficients of determination for log Kp versus log $P_L$ plot were> 0.76 $(p<0.0001)$, except for 3 samples). As a result, the variations in the slope among the sampling period may be due to change of temperature, raining during sampling period and wind in this study.

• Journal of Welding and Joining
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• 제28권3호
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• pp.86-91
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• 2010

Stainless steel sheets are widely used as the structural material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. For fatigue design of gas welded joints such as fillet and plug type joint, it is necessary to obtain design information on stress distribution at the weldment as well as fatigue strength of gas welded joints. And also, the influence of the geometrical parameters of gas welded joints on stress distribution and fatigue strength must be evaluated. the ${\Delta}P-N_f$ curves were obtained by fatigue tests. Using these results, ${\Delta}P-N_f$ curves were rearranged in the ${\Delta}{\sigma}-N_f$ relation with the maximum stress at the edge of fillet welded joint.