• KSBB Journal
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• v.20 no.6
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• pp.431-437
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• 2005

Molecular methods were employed to investigate microorganisms in a thermophilic continuous stirred tank reactor(CSTR) used for continuous $H_2$ production. The reactor was inoculated with heat-treated anaerobic sludge and fed with a glucose-based medium. Denaturing gradient gel electrophoresis showed dynamic changes of bacterial populations in the reactor during 43 days of operation. Gas composition was constant from approximately 14 days but population shift still occurred. Populations affiliated with Fervidobactrium gondwanens and Thermoanaerobacterium thermosaccharolyticum were dominant on 21 and 41 days, respectively. Keeping pH of the medium at 5.0 could suppress methanogenic activity that was detected during initial operation period. $CH_4$ and mcrA detected in the samples obtained from the reactor or inoculum suggested the heat treatment condition employed in this study is not enough to remove methanogens in the inoculum. PCR using primer sets specific to 4 main orders of methanogens suggested that major $H_2$-consuming methanogens in the CSTR belong to the order Methanobacteriales.

• Korean Journal of Organic Agriculture
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• v.26 no.4
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• pp.775-787
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• 2018

This study was conducted to investigate for the natural methane emission inhibitor as a feed additive no adversely effect on rumen fermentation. Five different Control (Wheat barn (0.05 g), MRA(Methane Reduction Additive)-1 (Allium fistulosum L. (0.05 g)), MRA-2 (Sodium Lauryl Sulfate (0.025 g) + Wheat barn (0.025 g) mixed), MRA-3 (Sodium Dodecyl Sulfate (0.025 g) + Wheat barn (0.025 g) mixed), and MRA-4 (Allium fistulosum L. (0.02 g) + Tannic acid (0.02 g) + Wheat barn (0.01 g) mixed) contents were used to perform 3, 6, 9, 12, 24 and 48 h incubation for in vitro fermentation. Ruminal pH values were ranged within normal ruminal microbial fermentation. Dry matter digestibility was not significantly different across the treatments during the whole fermentation time. Also, the result of microbial growth had no adversely effect on during the whole fermentation time. At 24 h, methane emission was significantly lower (P<0.05) than all treatments except to MRA-1. Especially, MRA-4 carbon dioxide emission was significantly lower (P<0.05) than control at 9, 24 and 48 h incubation. In addition MRA-4 propionate concentration was significantly higher (P<0.05) than control at 24 h incubation. The result of RT-PCR Ciliate-associated methanogens were significantly lower (P<0.05) at MRA-1, MRA-3 and MRA-4 than control at 24 h incubation. Based on the present results, MRA-4 could be suggestible methane emission inhibitor as a natural feed additive.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.8
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• pp.542-548
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• 2014

Effects of bromide ($Br^-$) and iodide ($I^-$) concentrations, chlorine ($Cl_2$) doses, pH, temperature, ammonia nitrogen concentrations, reaction times and water characteristics on formation of iodinated trihalomethanes (I-THMs) during oxidation of iodide containing water with chlorine were investigated in this study. Results showed that the yields of I-THMs increased with the high bromide and iodide level during chlorination. The elevated pH significantly increased the yields of I-THMs during chlorination. The formation of I-THMs was higher at $20^{\circ}C$ than $4^{\circ}C$, $10^{\circ}C$ and $30^{\circ}C$. In chloramination study, addition of ammonium chloride ($NH_4Cl$) markedly increased the formation of I-THMs. Among the water samples collected from seven water sources including wastewater treatment plant (WWTP) effluent water (EfOM water), prepared humic containing water (HA water) and algal organic matter (AOM) containing water (AOM water), EfOM water generated the highest yields of I-THMs ($12.31{\mu}g/mg$ DOC), followed by HA water ($4.96{\mu}g/mg$ DOC), while AOM water produced the lowest yields of I-THMs ($0.99{\mu}g/mg$ DOC). $SUVA_{254}$ values of EfOM water, HA water and AOM water were $1.38L/mg{\cdot}m$, $4.96L/mg{\cdot}m$ and $0.97L/mg{\cdot}m$, respectively. The I-THMs yields had a low correlation with $SUVA_{254}$ values ($r^2$ = 0.002).

• Applied Chemistry for Engineering
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• v.18 no.6
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• pp.618-624
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• 2007

thermochemical methane reforming consisting of two steps on Cu/Fe/Zr mixed oxide media was carried out using a fixed bed infrared reactor. In the first step, the metal oxide was reduced with methane to produce CO, $H_2$ and the reduced metal oxide in the temperature of 1173 K. In the second step, the reduced metal oxide was re-oxidized with steam to produce $H_2$ and the metal oxide in the temperature of 973 K. The reaction characteristics on the added amounts of Cu in Cu/Fe/Zr mixed oxide media and the cyclic tests were evaluated. With the increase of the added amount of Cu in Cu/Fe/Zr mixed oxide media, the conversion of $CH_4$, the selectivity of $CO_2$ and the $H_2/CO$ molar ratio were increased, while the selectivity of CO was decreased in the first step. On the other hand, the evolved amount of $H_2$ was decreased with increasing the added amount of Cu in the second step. The $Cu_xFe_{3-x}O_4/ZrO_2$ medium added with Cu of x = 0.7 showed good regeneration properties in the 10th cyclic tests indicating that the medium had high durability. In addition, the gasification of the deposited carbon in the water splitting step was promoted with the addition of Cu in the media.

• Journal of Life Science
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• v.17 no.11
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• pp.1555-1561
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• 2007

In order to know the effects of scoria, germanium, charcoal, ginger, stevia, and CLA(Conjugated Linoleic Acid) as biologically active materials on pathogenic microbes and rumen anaerobic microbes, the growth rate of pathogens (including Escherichia coli O157, Salmonella paratyphi, Listeria monocytogenes and Staphylococcus aureus) and in vitro lumen microbial growth, gas production, ammonia concentration, carboxymethyl-cellulase (CMCase) activity, and microbial populations were investigated. The growth of pathogenic microbes was inhibited by the supplement of 0.10% ginger. Ginger had powerful antimicrobial properties on all the pathogens used in this experiments. Additionally in the antibacterial assay by paper disc method, we could observe the clear zone of similar area with the positive control(antibiotics) for E. coli as applied with the 10% stevia or the 10% CLA only. The supplements of ginger, stevia and CLA in vitro rumen fermentation inhibited populations of rumen bacteria and protozoa. Particularly supplement of ginger resulted in remarkable reduction of the protozoa population, which means it might serve as a source inhibiting material of methane creation in the rumen.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.768-773
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• 2014

In this study, experimental and numerical studies for the synthesis of carbon nanotube(CNT) in methane counterflow diffusion flame have been performed. Methane mixed with acetylene($C_2H_2$) was used as a fuel gas and ferrocene was used as a catalyst for synthesis of CNT. The major parameters was $C_2H_2$ mixing rate and mixing rates were 2 %, 6 %, and 10 %. Characteristics of CNT formation on grid were analyzed from SEM images. the chemical reaction mechanism adopted is GRI-MECH 3.0. Numerical results showed that flame temperature and CO mole fraction were increased with increasing acetylene mixing rate. Experimental results showed that the CNT synthesis in 2% acetylene mixture flame better than that of 6% and 10% acetylene mixture flames. It can be considered that 6% and 10% acetylene mixture flames generated the excessive carbon source and then it interrupted the supplement of the carbon source into ferrocene catalyst. It can be found that the supply of appropriate quantity of carbon source can make effect to synthesis of high purity of CNT.

• Journal of Animal Science and Technology
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• v.53 no.2
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• pp.147-154
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• 2011

This study was conducted to evaluate the effects of saponin contained plant extracts on in vitro rumen fermentation characteristics and methane production. Ruminal fluid was collected from rumen cannulated Hanwoo steers fed rice straw and concentrate (5:5). Collected rumen fluids, corn starch and buffer including saponin contained plant extracts (ginseng, Ogapi, soapwort, tea plant and yucca; 0.5%/15 ml) were incubated at $39^{\circ}C$ for 24 h. All incubations were repeated five times. Rumen pH in all treatments was lower (p<0.05) compared with that of the control (no addition) during incubation time. The concentration of total VFA in all treatments was higher (p<0.05) than that of the control after 12h incubation. Compared with the control, the concentration of acetate and propionate in all treatments was lower and higher after 6h incubation, respectively. The concentration of $NH_3$-N in all treatments was lower (p<0.05) than that of the control except for Ogapi or yucca extracts supplementation. The number of protozoa in all treatments was significantly (p<0.05) lower than that of the control except for soapwort extract supplementation. The total gas production and methane production in all treatments was higher (p<0.05) and lower (p<0.05) compared with the control, except for ogapi or soapwort extracts supplementation after 12h incubation, respectively. Therefore, reduction in methane production by saponins may could be results from decreased protozoal population without any negative in vitro fermentation.

• Korean Journal of Plant Resources
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• v.31 no.4
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• pp.303-311
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• 2018

In this study, a preliminary evaluation of the antioxidant and anti-inflammatory activity of the Ficus erecta var. sieboldii (Miq.) King (FES) leaf extract has been performed to assess its potential as a natural resource for food and medicinal materials. FES was extracted using 70% EtOH and then fractionated sequentially using n-hexane, $CH_2Cl_2$, EtOAc, and n-BuOH. To screen for antioxidant and anti-inflammatory agents effectively, the inhibitory effect of the FES extracts on the production of oxidant stresses (DPPH, xanthine oxidase, and superoxide) and pro-inflammatory factors (NO, iNOS, COX-2, $PGE_2$, IL-6, and $IL-1{\beta}$) in the murine macrophage cell line RAW 264.7 activated with lipopolysaccharide (LPS) was examined. Among the sequential solvent fractions of FES, the $CH_2Cl_2$ and EtOAc fractions showed decreased production of oxidant stresses (DPPH, xanthine oxidase and superoxide), and the hexane and $CH_2Cl_2$ fractions of FES inhibited the production of pro-inflammatory factors (NO, iNOS, COX-2, and $PGE_2$). The $CH_2Cl_2$ fraction also inhibited the production of pro-inflammatory cytokines ($TNF-{\alpha}$, IL-6, and $IL-1{\beta}$). These results suggest that FES has a significant effects on the production of oxidant stresses and pro-inflammatory factors and may be used a natural resource for antioxidant and anti-inflammatory agents.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1996.10b
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• pp.91-97
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• 1996

Bench Scale급 가스화기를 이용하여 중국 대동탄에 대하여 O2/coal 비, 가스화기 운전 압력에 따른 가스화 특성을 조사하였다. 가스화기를 가압하는 방법으로 메탄과 산소의 버너를 이용하여 운전 압력까지 단시간 내에 가압하는 방법을 정립하였다. 가스화기 압력은 상압으로부터 10기압까지 실험을 실시하였으며, 10기압, 반응온도 1350-140$0^{\circ}C$, O2/coal 비(as-fed 기준) 0.9의 운전조건에서 탄소전환률 90%이상, 냉가스효율 60%, 그리고 heating value 1800 Kcal/N㎥ 정도의 생성가스 특성을 얻을 수 있었다.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.10a
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• pp.54-55
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• 1993

유기염소계 화합물들은 저렴한 가격과 우수한 세정력으로 기계, 금속, 섬유산업에서 뿐만아니라 일반적인 용제로도 널리 사용되고 있다. 그러나, 현재 산업현장에서사용 후 처리에 있어 유기염소계 화합물들을 완전히 제거하지 못하고 방출하는 실정이다. 또한, 음용수제조시 행해지는 염소소득으로 미량의 트리할로메탄(THM)인 클로로포름이 생성된다. 이러한 유기염소계 화합물들은 음용수 중에 포함되어 체내로 흡수되면 암을 유발시킨다. 따라서 물중에 용해된 미량의 유기염소계 화합물들을 제거하는 것이 필수불가결한 실정이다.