• 한국에너지공학회:학술대회논문집
• /
• 한국에너지공학회 2010년도 춘계학술 발표회
• /
• pp.132-137
• /
• 2010

• 대한약학회:학술대회논문집
• /
• 대한약학회 2001년도 Proceedings of the Pharmaceutical Society of Korea
• /
• pp.100.1-100.1
• /
• 2001

• Journal of Microbiology and Biotechnology
• /
• 제19권1호
• /
• pp.17-22
• /
• 2009

The mixotrophic growth with methanol plus thiosulfate was examined in nutrient-limited mixotrophic condition for Methylobacterium goesingense CBMB5 and Methylobacterium fujisawaense CBMB37. Thiosulfate oxidation increased the growth and protein yield in mixotrophic medium that contained 150mM methanol and 20mM sodium thiosulfate, at 144 h. Respirometric study revealed that thiosulfate was the most preferable reduced inorganic sulfur source, followed by sulfite and sulfur. M. goesingense CBMB5 and M. fujisawaense CBMB37 oxidized thiosulfate directly to sulfate, and intermediate products of thiosulfate oxidation such as polythionates, sulfite, and sulfur were not detected in spent medium and they did not yield positive amplification for tested soxB primers. Enzymes of thiosulfate oxidation such as rhodanese and sulfite oxidase activities were detected in cell-free extracts of M. goesingense CBMB5, and M. fujisawaense CBMB37, and thiosulfate oxidase (tetrathionate synthase) activity was not observed. It indicated that both the organisms use the "non-S4 intermediate" sulfur oxidation pathway for thiosulfate oxidation. It is concluded from this study that M. goesingense CBMB5, and M. fujisawaense CBMB37 exhibited mixotrophic metabolism in medium containing methanol plus thiosulfate and that thiosulfate oxidation and the presence of a "Paracoccus sulfur oxidation" (PSO) pathway in methylotrophic bacteria are species dependant.

• 한국축산식품학회지
• /
• 제36권6호
• /
• pp.760-768
• /
• 2016

The present study was performed to determine the effect of dietary supplementation with processed sulfur on the quality and stability of vacuum packaged pork during aging time. All groups were designated into two groups; NP, a group fed basal diet and SP, a group fed basal diet and processed sulfur, 3 g/kg feed. Following vacuum packaging, Longissimus dorsi muscles were vacuum-packaged and stored under refrigerated condition ($1-2^{\circ}C$) for 21 d. Weight loss of the SP group was lower (p<0.05) than that of the NP group. Interaction effect of shear force and cooking loss was observed (p<0.05). Redness values of the SP group at 14 and 21 d after storage were higher than those of the NP group (p<0.05). Lipid oxidation and volatile basic nitrogen (VBN) levels in the SP group were retarded (p<0.05) compared to that of the NP group during storage. Aspartic and glutamic acid in SP were higher than in NP (p<0.1). There was no significant (p>0.05) difference in TPC between the both groups during storage. Therefore, vacuum packaged pork from pigs fed processed sulfur had better aging yield and storage stability than pork from pigs fed basal diet.

• Tribology and Lubricants
• /
• 제28권6호
• /
• pp.321-327
• /
• 2012

Paraffin bio-based hydrotreated biodiesel(HBD) is originated from vegetable oil(the process can also be applied to animal fat) with the the chemical structure $C_nH_{2n+2}$. In the number of process of the oil or fat, the hydrogenation is significantly important to create a bio-based diesel fuel. This study is focused on lubricity characteristics of BTL diesel blends to use alternative diesel fuel in Korea. The BTL diesel are blended the different volume ratios (HBD 5(5 vol.% HBD - 95 vol.% diesel), HBD 10, HBD 20, HBD 30, HBD 40 and HBD 50. HBD with paraffin compounds showed a very high centane number, low sulfur content and free aromatic compound. Especially, the wear scar of HBD showed poor lubricity compared to automotive diesel due to the fuel composition, low sulfur content and free aromatic compound. Also, the lubricity specification of automotive diesel with different six HBD blends is within the limit by the Korean standards. Finally, HBD as an alternative diesel fuel is challengeable in transportation sector of Korea.

• 대한화학회지
• /
• 제34권3호
• /
• pp.260-266
• /
• 1990

N-methyl-2-amino-l-cyclopentene-l-dithiocarboxylic acid $(N-CH_3 acdc)$ 와 2-amino-l-cyclopentene-l-dithiomethyl ester $(S-CH_3 acdc)$의 전기화학적 거동을 직류폴라로그래피, 순환전압전류법 및 조절전위 전기량법을 사용하여 dimethylformamide(DMF) 용매 중에서 조사하였다. $N-CH_3$ acdc의 이합체는 + 0.98 V에서 2전자 산화반응을 거쳐 s가 한 원자 유리된 다섯 원자 고리를 형성하는 전극반응이 일어남을 알았다. 그러나, $S-CH_3 acdc의 경우에 있어서는 N-CH_3 acdc화합물과는 달리 다섯원자 고리를 형성하지 않았으므로 N-CH_3$ acdc와는 다른 전극반응을 일으킴을 확인하였다.

• Elastomers and Composites
• /
• 제56권4호
• /
• pp.223-233
• /
• 2021

In this study, epoxidized liquid isoprene rubber (E-LqIR) was used as a processing aid in a silica-filled natural rubber compound to improve the fuel efficiency, abrasion resistance, and oil migration problems of truck and bus radial tire tread. The wear resistance, fuel efficiency, and extraction resistance of the compound were evaluated according to the molecular weight of E-LqIR. Results of the evaluation showed that the E-LqIR compound had a lower chemical crosslink density than that of a treated distillate aromatic extract (TDAE) oil compound because of the sulfur consumption of E-LqIR. However, the filler-rubber interaction improved because of the reaction of E-LqIR with silica and crosslink with the base rubber by sulfur. As the molecular weight of E-LqIR increased, crosslink with sulfur was facilitated, and the filler-rubber interaction improved, resulting in improved abrasion resistance. The fuel efficiency performance of the E-LqIR compound was poorer than that of the TDAE oil compound because of the low chemical crosslink density and hysteresis loss at the free chain end of E-LqIR. However, the fuel efficiency performance improved as the molecular weight of E-LqIR increased.

• 한국식품과학회지
• /
• 제32권3호
• /
• pp.544-549
• /
• 2000

본 연구에서는 분석대상식품인 곡류, 과일류, 채소류, 어류둥 20종 180품목의 식품별에 따른 천연 이산화황의 함유량에 대해 모니어월리암스변법, 개량랭킹법 및 산증류/이온배제크로마토크래피법을 각각 적용하여 분석한 후 다음과 같은 결과를 얻었다. 본 연구에서 사웅한 각 실험방법별 회수율은 모니어월리암스변법은 $74{\sim}91%$, 개량랭킹법법은 $67{\sim}87%$, 산증류/이온배제크로마토그래피법은 $68{\sim}88%$의 회수율을 얻을 수 있었으며 모니어월리암스 변법에 의한 조사대상식품의 이산화황 분석결과는 $1.02{\sim}43.87\; ppm$의 범위를 보였고 마늘, 도라지, 파, 양배추 및 양파가 각각 43.87, 15.37, 11.50, 11.21 및 10.60 ppm의 높은 농도로 검출되었으며, 그 나머지 식품은 모두 10.00 ppm 미만으로 낮은 농도를 보였다. 개량랭킹법에 의한 조사대상식품의 이산화황 분석결과는 파와 마늘이 2.87 ppm과 6.41 ppm으로 높게 나타났고 나머지는 대부분 2.00 ppm미만의 낮은 농도를 보였다. 산증류/이온배제크로마토그래피법에 의한 조사대상식품의 이산화황 분석결과는 마늘, 양배추, 파, 양파, 감자 및 사과가 각각 15.43, 9.82, 5.74, 5.37, 2.14 및 0.49 ppm이 검출되었고, 그 나머지는 불검출이었다. 결론적으로, 20종 180품목을 3가지 분석방법을 적용하여 천연으로 존재하는 이산화황의 함유량을 조사한 결과, 여러 식품중 천연으로 존재하는 이산화황의 함유량을 모니터링하는데는 현행 식품공전의 공정시험법인 모니어월리암스변법이 타당한 방법이라고 생각되나, 건조된 파, 양파, 양배추등의 황화합물을 함유하는 식품의 경우에는 모니어월리암스법(AOAC공정법 990.28)에 규정되어 있는 것과 같이 이산화황이외의 황화합물에서 기인되는 휘발성물질이 이산화황으로 같이 검출되므로 건조된 파, 양파, 양배추등의 황화합물을 함유하는 식품의 경우에는 황화합물에서 기인되는 휘발성물질이 이온크로마토그래프에서 배제되고 이산화황만 검출되는 산중류/이온배제크로마토그래피법을 적용하여 분석하는 것이 타당하다고 사료된다.

• Bulletin of the Korean Chemical Society
• /
• 제21권6호
• /
• pp.628-634
• /
• 2000

Crosslink is the most important chemistry in a rubber vulcanizate. Degree and type of crosslinks of the vulcanizate determine its physical properties. Change of crosslink density and deformation of a rubber vulcanizate by thermal aging were studied using natural rubber (NR) vulcanizates with various cure systems (conventional, semi-EV, and EV) and different cure times (under-, optimum-, and overture). All the NR vulcanizates were deformed by the thermal aging at 60-100 $^{\circ}C.$ The higher the aging temperature is, the more degree of the deformation is. The undercured NR vulcanizates after the thermal aging were deformed more than the optimumand overcured ones. The NR vulcanizates with the EV cure system were less deformed than those with the conventional and semi-EV cure systems. The deformation of the NR vulcanizates was found to be due to change of the crosslink density of the vulcanizates. The crosslink densities of all the vulcanizates after the extraction of organic materials were also changed by the thermal ging. The sources to change the crosslink densities of the vulcanizates by the thermal aging were found to be dissociation of the existing sulfur crosslink and the formation of new crosslinks by free sulfur, reaction products of curing agents, and pendent sulfide groups.

• Asian Journal of Atmospheric Environment
• /
• 제6권1호
• /
• pp.41-52
• /
• 2012

Particulate sulfate in $PM_{2.5}$, sulfur dioxide ($SO_2$) and size-segregated aerosol particle number concentrations were measured at a site ($32^{\circ}19'N$, $129^{\circ}59'E$) on the southwestern Japan coast from 5 March to 10 April, 2010. Results show frequent episodic increases of sulfate and $SO_2$. Compared to the average concentration of sulfate $4.4{\pm}2.7\;{\mu}g\;m^{-3}$ in the whole observation period, episodic sulfate reached $10.5-20.1\;{\mu}g\;m^{-3}$. The variation of sulfate always synchronized with aerosol particles in the size range of $0.1-0.5 {\mu}m$, indicating the episodic sulfate was a consequence of the increase of the sub-micron particles. $SO_2$ did not have remarkable increase in any episodes of sulfate increase. During the passage of low pressure systems which loaded Asian dust in postfrontal air, concentrated sulfate appeared right behind the front but before dust arrival, suggesting the dominance of dust-free particulate sulfate. Weather and backward trajectory analyses revealed that air parcels with high sulfate passed eastern and northeastern China or Korean peninsula before arriving at the site. In contrast, those with high $SO_2$ passed an active volcano, Mt. Sakurajima, about 100 km in the south, suggesting the $SO_2$ was more likely from the volcanic emission. The ratio of sulfate to total sulfur compounds $({SO_4}^{2-})/({SO_4}^{2-}+SO_2)$ was 0.31-0.89 in continentally originated air while was 0.25-0.43 in the air having passed the volcano, showing more efficient conversions of $SO_2$ to sulfate in the air from the continent. The close dependence of the conversion on humidity in the continentally originated air was confirmed.