• Microbiology and Biotechnology Letters
• /
• v.38 no.4
• /
• pp.399-404
• /
• 2010

A hydrogen-producing bacterium (strain ES392) was isolated from pond water located in the Dong-Eui University, Busan, Korea. The cell was long-rod type ($1.4\;{\mu}m$) of about ($0.6\;{\mu}m$) in diameter, and not formed flagellum and spore. Phylogenetic analysis based on the 16S rRNA sequence and biochemical studies indicated that ES392 belonged to the genus Enterobacter sp. The optimum pH and temperature for hydrogen production was 7.5 and $35^{\circ}C$, respectively. The optimization of medium compositions which maximize hydrogen production from Enterobacter sp. ES392 was determined. As a result, the maximum hydrogen production was obtained under the conditions of 4% (w/v) sucrose, 0.5% (w/v) yeast extract and 50 mM potassium phosphate buffer (pH 7.5). Under batch culture conditions, the maximal hydrogen production and yield were obtained as 3481 mL/L and 1.33 mol/mol sucrose, respectively.

• Journal of Hydrogen and New Energy
• /
• v.22 no.6
• /
• pp.800-809
• /
• 2011

The reaction characteristics of an integrated reactor with steam reformer and catalytic combustor using anode offgas for high temperature fuel cells such as MCFC and SOFC have been experimentally investigated in the present study. The coupled reactor had a coaxial cylindrical shape, and the inner and the outer tube was packed with combustion catalysts and reforming catalysts, respectively. Thus, the endothermic steam reforming could proceed by absorbing heat from catalytic combustion of anode offgas. Results show that increasing inlet temperature and decreasing excess air ratio increased the reformer temperature, which led to the increase in $H_2$ yield. The reforming performance for SOFC conditions was better than that for MCFC conditions since the composition of flammable components became smaller for MCFC cases. Measured reformate composition under various test conditions correlated well with thermal equilibrium composition.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.6
• /
• pp.117-124
• /
• 2017

In this study, we investigated the optimization of process conditions by using the Six Sigma process, design of experiment (DOE) method and response surface method (RSM) to resolve dimensional deviation and appearance problems arising from the shortened process time of the mobile phone rear cover. The analysis of the trivial many was performed by 2-sample T-test and cooling time, and mold temperature and packing pressure were selected as the vital fews affecting the overall width of the product. The optimal conditions of the process were then studied using the DOE and the RSM. We analyzed the improvement effects by applying the selected optimal conditions to the production process and the results showed that the difference between the mean value and target value of the overall width stood at 0.01 mm, an improvement of 88.89% compared to current process that fell within the range of standard dimension. The short-term process capability stood at $4.77{\sigma}$, which implied an excellent technology level despite a decrease by $0.22{\sigma}$ compared to the current process. The difference in process capability decreased by $2.44{\sigma}$ to $0.41{\sigma}$, showing a significant improvement in management capability. Ultimately, the process time of the product was shortened from 18.3 seconds in the current process to 13.65 seconds, resulting in a 34.07% improvement in production yield.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.29 no.2
• /
• pp.207-213
• /
• 2014

The structural proteins of classical swine fever virus (CSFV) consist of nucleocapsid protein C and envelope glycoprotein $E^{rns}$ (E0), E1 and E2. Among them, E2, the most immunogenic of the CSFV glycoproteins, induces a protective immune response in swine. In this study, to determine the optimal expression conditions of glycoprotein E2 using baculovirus system, we investigated the influence of insect cells and media to the expression of recombinant E2. Recombinant virus containing glycoprotein E2 coding gene was constructed with bApGOZA DNA. Expression of the glycoprotein E2 was analyzed by SDS-PAGE and Western blot analysis using anti-CSFV E2 monoclonal antibodies. Expression of glycoprotein E2 in Sf21 cells was first observed after 3 days and reached a maximum on the 5th day after infection. Furthermore, the highest levels of glycoprotein E2 expression were observed at multiplicity of infection (MOI) of 5. When three different insect cell lines (Sf21, High-Five and Se301) were tested, High-Five cells showed the highest production. In addition, four different serum-free and serum-supplemented media, respectively, were tested for the expression of glycoprotein E2 and the budded virus (BV) titers. As a result, serum-supplemented medium provided the best conditions for protein production and the BV yield.

• YAKHAK HOEJI
• /
• v.39 no.1
• /
• pp.68-77
• /
• 1995

Aluminum magnesium silicate was synthesized by reacting the mixed solutions of sodium aluminate and magnesium chloride with sodium silicate solution in this study. The optimal synthesis conditions based on the yield of the product has been attained according to Box-Wilson experimental design. It was found that the optimal synthetic conditions of aluminum magnesium silicate were as follows: Reaction temperature=$69~81^{\circ}C$; concentration of two reactants, sodium aluminate and magnesium chloride= 13.95~14.44 w/w%; molar concentration ratio of the two reactants, [NaAlO$_{2}$]/MgCl$_{2}$]=3.63~4.00; reaction time= 12~15 min; drying temp. of the product=$70~76^{\circ}C$. Aluminum magnesium silicate synthesized under the optimal synthesis condition was dispersed in 0.75, 1.0 and 1.5w/w% aqueous solution or suspension of six dispersing agents, and the Theological properties of the dispersed systems prepared have been investigated at $15^{\circ}C$ and $25^{\circ}C$ using Brookfield LVT Type Viscometer. The acid-consuming capacity of the most excellent product was 272~278 ml of 0.1N-HCl per gram of the antacid. The flow types of 5.0 w/w% aluminum magnesium silicate suspension were dependent upon the kind and concentration of dispersing agents added. The apparent viscosity of the suspension was generally increased with concentration of dispersing agents and was not significantly changed or decreased as the temperature was raised. A dispersing agent, hydroxypropyl cellulose suspension, exhibited an unique flow behavior of antithixotropy. The flow behavior of the suspension dispersed in a given dispersing agent not always coincided with that of the dispersing agent solution or suspension itself.

• Korean Journal of Food Science and Technology
• /
• v.13 no.4
• /
• pp.334-339
• /
• 1981

Surface color, water extract color and soluble solids of the roasted barley resulted from the various roasting conditions were determined to establish the optimum roasting conditions. The correlation coefficients between the surface color of the roasted barley and its ground was in the range from 0.957 to 0.994, and which showed the internal color being well represented that of surface of the roasted grain. The degree of roasting was determined maim by the roasting temperature, rather than by the total heat energy input during roasting. The maximum yield of the water soluble solids was 68% and obtained from the barley roasted at $232^{\circ}C$ for 25 minutes. The readings of Y-value of the roasted whole barley was a good index to judge and control the degree of roasting.

• Mycobiology
• /
• v.45 no.4
• /
• pp.392-400
• /
• 2017

Peanut yield and quality are seriously affected by pod rot pathogens worldwide, especially in China in recent years. The goals of this study are to analyze the structure of fungal communities of peanut pod rot in soil in three peanut cultivars and the correlation of pod rot with environmental variables using 454 pyrosequencing. A total of 46,723 internal transcribed spacer high-quality sequences were obtained and grouped into 1,706 operational taxonomic units at the 97% similarity cut-off level. The coverage, rank abundance, and the Chao 1 and Shannon diversity indices of the operational taxonomic units were analyzed. Members of the phylum Ascomycota were dominant, such as Fusarium, Chaetomium, Alternaria, and Sordariomycetes, followed by Basidiomycota. The results of the heatmap and redundancy analysis revealed significant variation in the composition of the fungal community among the three cultivar samples. The environmental conditions in different peanut cultivars may also influence on the structure of the fungal community. The results of this study suggest that the causal agent of peanut pod rot may be more complex, and cultivars and environmental conditions are both important contributors to the community structure of peanut pod rot fungi.

• Korean Journal of Medicinal Crop Science
• /
• v.28 no.4
• /
• pp.254-259
• /
• 2020

Background: Centella asiatica is a well-known medicinal plant having a wound healing effect. In this study, the growth, asiaticoside content, and antioxidant components and activity were investigated in C. asiatica resources under different cultivation and irrigation conditions. Methods and Results: The cultivation and irrigation methods were divided as greenhouse and open field, and sprinkler and sub irrigation. respectively. Growth characteristics were measured in aerial parts of C. asiatica. Asiaticoside content was analyzed using high performance liquid chromatography. Total polyphenol, total flavonoid and 2,2-diphenyl-1picryl hydrazyl (DPPH) radical scavenging activity were analyzed for antioxidant activities. Growth was higher under greenhouse and sub irrigation than open field and sprinkler conditions. In the leaves, asiaticoside content was 53.45 mg/g (open field) and 34.38 mg/g (sub irrigation), total polyphenol was 41.14 mg/g (open field) and 25.73 mg/g (sub-irrigation), and total flavonoid was 27.26 mg/g (open field) and 23.72 mg/g (sub-irrigation). DPPH radical scavenging activity in the leaves was 85.97 mg·ascorbic acid equivalent (AAE)/g (open field) and 54.83 mg·AAE/g (sub irrigation). Conclusions: Asiaticoside and antioxidant components and activity were not accompanied with high yield, although high growth was observed under greenhouse conditions. Therefore, cultural requirements of C. asiatica should be sufficiently considered to suit each purpose.

• Journal of Bio-Environment Control
• /
• v.12 no.1
• /
• pp.38-44
• /
• 2003

This work was conducted to estimate amounts of irrigating water during the growing periods of pepper after estimating water consumption in the plastic film house in 1997 and 1998. Evapo-transpiration (ET) under conditions of a black and white PE mulch and sandy or clay loam soil which enhanced the growth and yield of red peppers was greater than that at the bare and sand soil. Average ET of pepper grown in pots accounted for 56.5%∼79.7% of total supplying water in 1997 and 1998. Most of ET was proportioned to the transpiration amount (91∼94%), but there was some difference between amounts of ET and transpiration plus evaporation. Although 57 depended on conditions of the soil texture and plant growth, transpiration for pepper growing periods was amounted to 337.7∼774.3 m in the clay soil,910.6 m in the sandy loam soil, and 253.1 mm in the sandy soil.

• Journal of Powder Materials
• /
• v.28 no.3
• /
• pp.221-226
• /
• 2021

We fabricate the non-equiatomic high-entropy alloy (NE-HEA) Fe_49.5Mn₃₀Co₁₀Cr₁₀C_0.5 (at.%) using spark plasma sintering under various sintering conditions. Each elemental pure powder is milled by high-energy ball milling to prepare NE-HEA powder. The microstructure and mechanical properties of the sintered samples are investigated using various methods. We use the X-ray diffraction (XRD) method to investigate the microstructural characteristics. Quantitative phase analysis is performed by direct comparison of the XRD results. A tensile test is used to compare the mechanical properties of small samples. Next, electron backscatter diffraction analysis is performed to analyze the phase fraction, and the results are compared to those of XRD analysis. By combining different sintering durations and temperature conditions, we attempt to identify suitable spark plasma sintering conditions that yield mechanical properties comparable with previously reported values. The samples sintered at 900 and 1000℃ with no holding time have a tensile strength of over 1000 MPa.