• International Journal of Advanced Culture Technology
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• v.3 no.1
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• pp.31-38
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• 2015

Coking accumulations via dry methane reforming (DMR) over 10NAM monolithic catalyst and pelletized catalyst was investigated. 10NAM catalyst was synthesized and coated on a wall of monolithic reactor. Pelletized catalyst of 10NAM was also prepared for the comparison. Consequently, catalyst was characterized by BET, $H_2-TPR$ and $H_2-TPD$. The catalytic reaction was undergone at $600^{\circ}C$ under atmospheric pressure and $CH_4$ to $CO_2$ reactant ratio of 1:2. The coking formation over spent catalyst was then carried out in the hydrogen flow using temperature programmed technique (TPH). According to the results, DMR over 10NAM monolithic catalyst exhibits a minimized coking formation comparing to the use of pelletized catalyst. This could be attributed to a prominent heat transfer efficiency of the monolithic catalyst.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.11
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• pp.1562-1570
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• 2014

The effects of Lactobacillus mucosae (L. mucosae), a potential direct fed microbial previously isolated from the rumen of Korean native goat, on the rumen fermentation profile of brewers grain were evaluated. Fermentation was conducted in serum bottles each containing 1% dry matter (DM) of the test substrate and either no L. mucosae (control), 1% 24 h broth culture of L. mucosae (T1), or 1% inoculation with the cell-free culture supernatant (T2). Each serum bottle was filled anaerobically with 100 mL of buffered rumen fluid and sealed prior to incubation for 0, 6, 12, 24, and 48 h from which fermentation parameters were monitored and the microbial diversity was evaluated. The results revealed that T1 had higher total gas production (65.00 mL) than the control (61.33 mL) and T2 (62.00 mL) (p<0.05) at 48 h. Consequently, T1 had significantly lower pH values (p<0.05) than the other groups at 48 h. Ammonia nitrogen ($NH_3$-N), individual and total volatile fatty acids (VFA) concentration and acetate:propionate ratio were higher in T1 and T2 than the control, but T1 and T2 were comparable for these parameters. Total methane ($CH_4$) production and carbon dioxide ($CO_2$) were highest in T1. The percent DM and organic matter digestibilities were comparable between all groups at all times of incubation. The total bacterial population was significantly higher in T1 (p<0.05) at 24 h, but then decreased to levels comparable to the control and T2 at 48 h. The denaturing gradient gel electrophoresis profile of the total bacterial 16s rRNA showed higher similarity between T1 and T2 at 24 h and between the control and T1 at 48 h. Overall, these results suggest that addition of L. mucosae and cell-free supernatant during the in vitro fermentation of dried brewers grain increases the VFA production, but has no effect on digestibility. The addition of L. mucosae can also increase the total bacterial population, but has no significant effect on the total microbial diversity. However, inoculation of the bacterium may increase $CH_4$ and $CO_2$ in vitro.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.874-882
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• 2019

In this study, the gasification characteristics of four types of unused woody biomass and one waste wood in a lab-scale bubbling fluidized bed gasifier (Diameter: 0.11 m, Height: 0.42 m) were investigated. Effect of equivalence ratio (ER) of 0.15-0.3 and gas velocity of $2.5-5U_0/U_{mf}$ are determined at the constant temperature of $800^{\circ}C$ and fuel feeding rate of 1 kg/h. The silica sand particle having an average particle size of $287{\mu}m$ and olivine with an average particle size of $500{\mu}m$ were used as the bed material, respectively. The average product gas composition of samples is as follows; $H_2$ 3-4 vol.%, CO 15-16 vol.%, $CH_4$ 4 vol.% and $CO_2$ 18-19 vol.% with a lower heating value (LHV) of $1193-1301kcal/Nm^3$ and higher heating value (HHV) of $1262-1377kcal/Nm^3$. In addition, it was found that olivine reduced most of C2 components and increased $H_2$ content compared to silica sand, resulting in cracking reaction of tar. The non-condensable tar decreases by 72% ($1.24{\rightarrow}0.35g/Nm^3$) and the condensable tar decreases by 27% ($4.4{\rightarrow}3.2g/Nm^3$).

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.8-16
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• 2019

One of the methods for low-pollution combustion, flue gas recirculation(FGR) is effective to reduce nitrogen oxides and it was applied in CH₄/air premixed counterflow flames to identify the change of flame characteristics and NOx mechanisms. Considering that the mole fraction of the products varied depending on the strain rates, the major products: CO₂, H₂O, O₂ and N₂ were recirculated as a diluent to reflect the actual combustion system. With the application of the FGR technique, a turning point of maximum flame temperature under certain strain rate condition was found. Furthermore as the recirculation ratio increased, the tendency of NO was changed before and after the turning point and the analysis on thermal NO and Fenimore NO production was conducted.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.51-51
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• 2008

Carbon nanotubes (CNTs) have long been reported as an ideal material due to their excellent electrical conductivity and chemical and mechanical stability as well as their high aspect ratios for field emission devices. CNT emitters made by screen printing the organic binder-based CNT paste may act as a source to release gases inside a vacuum panel. These residual gases may cause a catastrophic damage by electrical arcing or ion bombardment to the vacuum microelectronic devices and may change their physical or electrical properties by adsorbing on the CNT emitter surface. In this study, we analyzed the composition of residual gases inside the vacuum-sealed panel by residual gas analyzer (RGA), investigating the effects of individual gases of different kinds at several pressures on the field emission characteristics of CNT emitters. The residual gases included $H_2$, CO, $CO_2$, $N_2$, $CH_4$, $H_2O$, $C_2H_6$, and Ar. Effect of residual gases on the field emission was studied by observing the variation of the pulse voltages with the duty ratio of3.3% to keep the constant emission current of $28{\mu}A$. Each gas species was introduced to a vacuum chamber up to three different pressures ($5\times10^{-7}$, $5\times10^{-6}$, and $5\times10^{-5}$ torr) each for 1 h while electron emission was continued. The three different pressure regions were separated by keeping a high vacuum of $\sim10^{-8}$ torr for a 1 h. The emission was terminated 6 h after the third gas exposure was completed. Field emission characteristics under residual gases will be discussed in terms of their adsorption and desorption on the surface of CNTs and the resultant change of work function.

• Journal of Korean Society of Forest Science
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• v.77 no.1
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• pp.92-99
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• 1988

The dark respiration, photosynthesis($CO_2$ refixation), $CO_2$ balance and chlorophyll content of 1st-year conelets and 2nd-year cones of Korean pine(Pinus koraiensis S.et.Z.) were investigated after pollination up to the end of maturation. The results obtained are as follows : 1. The growth of 1st-year conelet was 3.6cm in length. 2.4cm in diameter and 3.058 in dry weighs during the first year. The growth of 2nd-year mature cone was 13.5cm in length, 9.3cm in diameter and 141.0g in dry weight in the late of 2nd-year. 2. The refixation of carbon dioxide released from a cone by the dark respiration was less than 50 percent at light saturation through the growing period. The refixation of carbon dioxide released by dark respiration for one year was 7.3 percent in 1st-year conelets and 8.7 percent in 2nd-year cones. 3. The dark respiration rate of cones by increasing temperature was rapidly increased with increasing temperature up to $25^{\circ}C$. The dark respiration rate of cones was much higher in non-growing season than that in growing season at the same temperature. 4. The rates of dark respiration and $CO_2$ refixation, based on the dry weight, were much higher in 1st-year conelet than that in 2nd-year cone. 5. The $CO_2$ balance for a cone was negative from pollination to the end of maturation. The net dark respiration loss for a cone was 7.23g $CO_2$/year in 1st-year conelet and 164.8g $CO_2$/year in 2nd-year cone. 6. The respiratory loss efficiency for a cone(=$CH_2O$ weight calculated by net dark respiration/dry weight of cone) for one year was 1.61 in 1st-year conelet and 0.81 in 2nd-year cone for one year. 7. The total chlorophyll content of surface scale of the cone was lower than 2mg/g dw through the growing period, and chl. a/b ratio was 2 to 3.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.269-275
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• 2021

In this study, ordered mesoporous silica-supported Ni catalysts were prepared for catalytic partial oxidation of methane (CPOM) by using electroless nickel plating method. Unlike conventionally impregnated catalysts, the electrolessly-plated nickel catalyst showed that nickel was highly dispersed and formed stably on silica-supported surface. It was verified by TEM-EDS analysis. During the activity tests, the electrolessly-plated nickel was barely sintered and the amount of carbon deposition was very small. Consequently, the catalyst was far less deactivated, while the sintering was significantly observed in the cases of the catalysts prepared by the conventional impregnation method. Regarding the palladium-promoted catalysts, the reducibility of nickel was increased, and the reaction performances were enhanced in terms of CH4 conversion and H2/CO ratio of produced syngas.

• The Korean Journal of Mycology
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• v.29 no.1
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• pp.1-8
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• 2001

To examine the structural properties of the proteoglycan (GMPG, Ganoderma lucidum mycelial proteoglycan) obtained from mycelia in Ganoderma lucidum IY009, we obtained the low and high molecular proteoglycan by ultrafiltration and sepharose CL-4B column chromatography. The physicochemical properties of these fractions were as follows. When the proteoglycan separated by ultrafiltration and sepharose CL-4B column chromatography, its was not fractionated completely. The molecular weight of high molecular proteoglycan by the gel column chromatography (CH) was 250 kD and 2,000 kD, and low molecular proteoglycan was 12kD. The total carbohydrate was consisted of 75.7% (UH) and 96.7% (CH), and the low fraction was 72.7% (UL) and 87.1% (CL), respectively. The sugar of high and low molecular proteoglycan composed of glucose, mannose, fructose, galactose, xylose, ribose and arabinose. Glucose contents of all fraction were ranged from $46.9%{\sim}82.4%$ of the total sugar and the ratio of ${\alpha}$\;and\;{\beta}-glucose$ was $0.84{\sim}1.14$, and its indicated the proteoglycan to be ${\beta}-glucan$. Amino acids pattern showed that the fractions contained a large amount of aspartie acid, glutamic acid, alanine and leucine. These fractions showed the characteristics of IR absorption for ${\beta}-glucan$ at $890\;cm^{-1}\;and\;^{13}C-NMR$ spectroscopy showed the presence of the ${\beta}-1,3-glucan$ and a ${\beta}-1,6-glucan$.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.229-234
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• 2008

Korea Electric Power Corporation (KEPCO) has started the nation's first biogas-microturbine project in the city of Gongju as an effort to encourage the utilization of wasted biogas containing useful energy source in the form of $CH_4$. The goal of the project is to set up the biogas microturbine co-generation system for utilizing biogas as an energy source and improving the economics of the wastewater treatment plant. Wastewater treatment processes were investigated in depth to find improvement possibility. Changes in internal recirculation ratio and pre-treatment degree are needed to optimize plant operation and biogas production. Biogas pre-treatment system satisfies Capstone's fuel condition requirement with the test result of 99.9% and 90.2% of hydrogen sulphide and ammonia is removal performance. Installation of microturbine and manufacture of heat exchanger to warm anaerobic digester has been done successfully. Expected economic profit produced by the system is coming from energy saving including electricity 115,871kWh/year and heat contained in exhaust gas 579GJ/year.

• YAKHAK HOEJI
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• v.33 no.5
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• pp.267-272
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• 1989

The durg-macromolecule conjugates i.e. 5-fluorouracil-1-acetyl-human serum albumin(FU-AA-HSA, 8) and 5-fluorouracil-1-acetyl-poly-L-lysine(FU-AA-polylys, 9) have been synthesized and purified by sephadex G-25 gel filtration with 0.05M phosphate buffer(pH 7.5). The analyses of conjugates gave the molar ratio of FU-AA : HSA of 70-100:1 and FU-AA: poly-L-lysine of 109:1. The weight percent of FU-AA(as $FU-CH_2CO-$) in FU-AA-HSA conjugate was 16-22% and the one in FU-AA-polylys was 22.4%.