• Journal of the Korean Society for Heat Treatment
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• v.9 no.3
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• pp.212-218
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• 1996

To clarify the influence of precipitation microstructure and inclusion on the monotonic tensile fracture behaviors in 2090 alloy aged at $180^{\circ}C$, the detailed measurement of hardness, tensile strength, elongation and the observation of scanning electron micrography, transmision electron micrography have been carried out. The transgranular shear ductile fracture has been observed in specimen quenched after solution treatment at $500^{\circ}C$ for 45min. While the under-aged specimen was fractured in both transgranular shear ductile and intergranular fracture mode, the fracture mode of peak-aged and over-aged alloy was predominantly intergranular fracture. The fracture behavior of each ageing condition was influenced by the change of precipitation microstructural features. In the case of peak-aged and over-aged alloys, the coarse and heterogeneous slip band caused by both shearable nature of the ${\delta}^{\prime}(Al_3Li)$ precipitates and PFZ along the high angle grain boundary aid the localization of deformation, resulting in low energy intergranular fracture. It was also estimated that the fractured T-type intermetallic phases (inclusion) and the equilibrium ${\delta}$(AlLi) phases which were formed at grain boundaries palyed an important role in promoting intergranular fracture mode.

• Food Science and Preservation
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• v.16 no.6
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• pp.875-883
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• 2009

We investigated the effects of manufacturing method on the quality of beef jerky using electron micrography. Six types of beef jerky were prepared by the addition of sugar (A), licorice (B), one of three kinds of spice extract (clove: C, fennel fruit: D, and Chungyang green pepper extract: E), or a mixture of all spice extracts (F). Microstructural changes in beef jerky during preparation by drying, with respect to drying method and the nature of the added spice extract, were observed by scanning electron micrography (SEM) and transmission electron micrography (TEM). The latter technique showed that the microstructure of fresh meat showed actin and myosin in myofibril lines, and also mitochondria and inner membranes. Beef muscle structure was broken at many myofibril lines and decomposition of inner membrane material was evident after seasoning. SEM of air-blast dried beef jerky with added medicinal herb extracts showed both large spaces and regular myofibrils, whereas hot air-dried beef jerky had no spaces and the muscle myofibrils were still evident. After review of all available micrographs from SEM and TEM, we concluded that use of medicinal herb extracts could be helpful in preserving the muscle myofibril structure during drying, and the air-blast drying method is recommended to optimize the textural quality characteristics of beef jerky.

• Korean Journal of Weed Science
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• v.14 no.2
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• pp.144-155
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• 1994

Scanning electron micrography and Transmission electron micrography studies were performed on the surfaces of stem(coleoptiles) of rice and barnyardgrass under various cropping patterns at 5 days after seeding or transplanting. Stem surfaces of rice under dry condition possessed rodlet-like epicuticular waxes, trichomes, stomata and cork cell layer in both broadcast and drilled rice while barnyardgrass had only thread-like epicuticular waxes, but trichomes, stomata and cork cell layers were not found. However, rice under water condition has no rodlet-like waxes, stomata and cork cells, and barnyardgrass was similar to that under dry condition. On the other hand, those on stems of 8-day and 25-day transplanted rice were well arranged and developed compared with those of direct seeded rice. Electron micrography showed significant difference in thickness of outer epidermal cell walls of rice and barnyardgrass under dry, water and transplanting condition. Thickness of outer epidermal cell was greater in transplanted rice, dry direct seeded rice, water-direct seeded rice and barnyardgrass in descending order.

• Korean Journal of Veterinary Research
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• v.14 no.1
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• pp.77-90
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• 1974

Hemolytic reaction of normal fresh chicken serum on sheep erythrocytes was studied and the following experimental results were obtained and summarized. 1. Chicken sera, 258 (78%) out of 344 samples showed hemolytic activity on sheep erythrocytes. 2. Distribution of a different hemolytic titer of chicken sera was not dependent to sex and age difference of test chicken. 3. Hemolytic activity of serum component obtained from normal fresh chicken was heat inactivated at $56^{\circ}C$. 30 minutes heating. 4. The most enhanced hemolytic activity of chicken serum on sheep erythrocytes was observed at the incubation temperature of $46^{\circ}C$. 5. The most effective pH for the hemolytic reaction of chicken serum on sheep erythrocytes was observed at 7.0, and pH 6.0 or 8.5 resulted less or no hemolysis. 6. Hemolytic reaction of chicken serum and sheep erythrocytes required Mg⧻ and Ca⧻ ions as, co-factor, and the former was required more compared to the latter. 7. Hemolytic activity of chicken serum was observed in ChC 2, 4 fraction but not in ChC 1, 3, ChC 3, 4, ChC 1, 2, 4 and ChC 1, 2, 3 fractions. 8. In electron micrography, morphological changes of sheep erythrocyte membrane by normal chicken serum was similar to that of immune hemolysis: that was, the hemolytic hole was circular and it was surrounded with a white ring. 9. Electron micrography of morphological changes on sheep erythrocyte membrane indicated that the size of hemolytic hole and white ring were functional to the chicken serum concentration used and reaction time.

• Journal of the Korean Society of Combustion
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• v.15 no.2
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• pp.19-26
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• 2010

Combustion behavior of pulverized coal particles in a post-combustion gas reactor was investigated. Radiation emission from coal particles were analyzed by direct photograph and $CH^*$ radical chemiluminescence intensity. Coal particles were sampled during the combustion and were observed by scanning electron microscopy (SEM) and cross section micrograpy technique. Two coal types(one bituminous and one subbituminous coals typically used in the Korean power plants) were tested at typical combustion environment. Gas flow conditions were controlled to represent temperature and oxygen concentration. Experimental data were discussed along with conceptual descriptions of pulverized coal combustion, where particle heat-up, release and combustion of volatiles, and char combustion were sequentially progressed.

• Journal of Environmental Science International
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• v.2 no.3
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• pp.201-206
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• 1993

The concentration of Total Suspended Particulates(T.S.P), size distribution of suspended particulates, and soluble anions of T.S.P in atmosphere of industrial region in Busan were investigated. T.S.P was measured by High-Volume Air Sampler and particle size distribution was measured by Anderson Air Sampler. We analyzed the chemical component of the T.S.P by ion Chromatography and measure4 the shape and size of T.S.P by Scanning Electron Micrography The small size of T.S.P mainly exist in industrial region, but the large size of T.S.P mainly exist in residentail area.

• Journal of the Korean Society for Heat Treatment
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• v.20 no.6
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• pp.293-298
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• 2007

Influences of aluminum carbide ($Al_4C_3$) addition on microstructure and damping capacity of Mg-3%Al casting alloy have been investigated based on experimental results of optical micrography, scanning electron microscopy with energy-dispersive spectrometry analysis and damping capacity measurement at RT. The addition of $Al_4C_3$ particles results in an efficient grain refinement. The damping capacity shows an increasing tendency with an increase in $Al_4C_3$ content. The damping value associated with $Al_4C_3$ particles is linearly dependent on the volume fraction of $Al_4C_3$ particles to the 2/3 power, $f_{2/3}$, which corresponds to the total surface area of the particles.

• Proceedings of the Microbiological Society of Korea Conference
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• 2001.11a
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• pp.26-36
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• 2001

A novel approach of microbiologically-enhanced crack remediation (MECR) has been initiated and evaluated in this report. Under the laboratory conditions, Bacillus pasteurii was used to induce $CaCO_3$ precipitation as the microbial urease hydrolyzes urea to produce ammonia and carbon dioxide. The ammonia released in surroundings subsequently increases pH, leading to accumulation of insoluble $CaCO_3$. Scanning electron micrography (SEM) and x-ray diffraction (XRD) analyses evidenced the direct involvement of microorganisms in $CaCO_3$ precipitation. In biochemical studies, the primary roles of microorganisms and microbial urease were defined. Furthermore, the role of urease in $CaCO_3$ precipitation was characterized utilizing recombinant Escherichia coli that encoded B. pasteurii urease genes in a plasmid. Microorganisms immobilized in polyurethane (PU) polymer were applied to remediate concrete cracks. Although microbiologically- induced calcite precipitation enhanced neither the tensile strength nor the modulus of elasticity of the PU polymer, cement mortar whose crack was remediated with the cemaden polymer showed a significant increase in compressive strength. Through detailed investigation, MECR showed an excellent potential in cementing cracks in granite, concrete, and beyond.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1571-1576
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• 2010

Two bacterial strains designated as CT2 and CT5 were isolated from highly alkaline cement samples using the enrichment culture technique. On the basis of various physiological tests and 16S rRNA sequence analysis, the bacteria were identified as Bacillus species. The urease production was 575.87 U/ml and 670.71 U/ml for CT2 and CT5, respectively. Calcite constituted 27.6% and 31% of the total weight of sand samples plugged by CT2 and CT5, respectively. Scanning electron micrography analysis revealed the direct involvement of these isolates in calcite precipitation. This is the first report of the isolation and identification of Bacillus species from cement. Based on the ability of these bacteria to tolerate the extreme environment of cement, they have potential to be used in remediating the cracks and fissures in various building or concrete structures.

• Transactions of Materials Processing
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• v.8 no.3
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• pp.289-289
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• 1999

This paper describes the investment casting of TiAl alloys. The effects of mold material and mold preheating temperature for the investment casting of TiAl on metal-mold interfacial reaction were investigated by means of optical micrography, hardness profiles and an electron probe microanalyzer. The mold materials examined were colloidal silica bonded ZrO₂, ZrSiO₄, A1₂O₃and CaO stabilized ZrO₂. When compared with conventional titanium a1loy, the high aluminum concentration of TiAl alloys helps to lower their reactivity in the molten state. The A1₂O₃mold is a promising mold material for the investment casting of TiAl in terms of the thermal stability, formability and cost. Special attention need to be paid to thermal stability and mold preheating when developing the investment calling of TiAl alloys.