• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.114-115
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• 2006

[ $FerroTitanit^{(R)}$ ] is an extremely high alloyed PM material containing about 20 to 35 wt.% titanium based carbides. Such materials are designed to achieve a high wear resistance, but the high volume fraction of hard phases causes a comparable low ductility in case of tensile loading. In the present study the mechanical properties of different Ferro-Titanit grades (variations in chemical composition and in heat treatment) were investigated by means of tensile tests. The mechanical properties and the fracture behaviour will be related to the chemical composition, the heat treatment and the microstructure.

• Journal of Microbiology and Biotechnology
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• v.31 no.3
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• pp.429-438
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• 2021

Bacterial cellulose (BC) is widely used in the food industry for products such as nata de coco. The mechanical properties of BC hydrogels, including stiffness and viscoelasticity, are determined by the hydrated fibril network. Generally, Komagataeibacter bacteria produce gluconic acids in a glucose medium, which may affect the pH, structure and mechanical properties of BC. In this work, the effect of pH buffer on the yields of Komagataeibacter hansenii strain ATCC 53582 was studied. The bacterium in a phosphate and phthalate buffer with low ionic strength produced a good BC yield (5.16 and 4.63 g/l respectively), but there was a substantial reduction in pH due to the accumulation of gluconic acid. However, the addition of gluconic acid enhanced the polymer density and mechanical properties of BC hydrogels. The effect was similar to that of the bacteria using glycerol in another carbon metabolism circuit, which provided good pH stability and a higher conversion rate of carbon. This study may broaden the understanding of how carbon sources affect BC biosynthesis.

• Journal of the Korean Applied Science and Technology
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• v.25 no.1
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• pp.15-22
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• 2008

The effects of fillers on the mechanical and thermal properties of glass/novolac composites have been studied. The matrix polymer and reinforcement were novolac type phenolic resin and milled glass fiber, respectively. Three different fillers, such as calcium carbonate, aluminum oxide, and wood powder were used for glass fiber reinforced plastic(GFRP) manufacture. Gravity, moisture content, tensile and flexural strength were measured to analyze the mechanical properties of GFRP and the final composites was burned in the electronic furnace at $1000^{\circ}C$ to confirm thermal properties GFRP containing aluminium oxide shows the highest thermal stability with 32% of weight loss at $1000^{\circ}C$ for one hour. GFRP containing calcium carbonate shows the maximum flexural strength (146 MPa), but that containing wood powder dose the highest tensile strength (65 MPa). Conclusively, we found that the characteristics of final composites strongly depend on several factors, such as types of materials, contents and chemical affinity of fillers. Therefore, it is very important to set up the combination of fillers for GFRP manufacturing to improve both mechanical and thermal properties at the same time.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.6
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• pp.485-497
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• 2001

For a period of 5 days, the quality of breads with Paecilomyces japonica powder were investigated using chemical, sensory, and mechanical evaluations at $25^{\circ}C$. The result of analysis of chemical properties revealed that the pH value of dough was increased as the amount of Paecilomyces japonica powder increased, but volume of dough and baking loss rate were decreased. Breads with 1% and 2% Paecilomyces japonica powder showed a good overall preference in sensory evaluation. As storing time passed. moisture content, lightness, and redness were decreased in all breads, but yellowness increased. Hardness and gumminess of texture analysis were increased as storing time passed, but springiness decreased. Springiness of the mechanical properties was negatively correlated with pH value of dough and volume of bread, while was positively correlated with volume of dough and baking loss rate. In the analysis of correlation between sensory and mechanical properties showed that hardness of mechanical properties had negative correlation with softness, moistness, and springiness. Cohesiveness of mechanical properties had positive correlation with acceptability.

• Journal of the Korea Furniture Society
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• v.11 no.1
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• pp.75-84
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• 2000

Ginkgo trees have long been planted in Korea as roadside trees and ornamental trees, but the wood was seldom used except some utilization for small artifacts. Soaring prices of imported wood and future uncertainty about long-term supply of foreign woods have stimulated research on value-added utilization of less-utilized domestic wood resources such as Ginkgo wood. The properties of Ginkgo wood were investigated to determine its utilization potential in this study, and the results of anatomical, physical, and mechanical studies were presented with chemical compositions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.571-576
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• 2007

In this paper, we have investigated chemical, mechanical and structural properties by changing the content of carbon nanotube, Which is a component part of semiconductive shield in underground power transmission cable. The multi luminescence spectrometer MLA-GOLDS was used to investigate chemical properties of specimens. Also, the density meter EW-200SG was used to investigate the mechanical properties of specimens, and the FE-SEM S-4300 in Hitachi was used for dispersion of CNT(Carbon nanotube). As a result, the cl intensity, which show the effect of oxidation, was decreased by CNT of 1 [wt%], and the density of semiconductive shield materials with CNT and EEA(Ethylene Ethyl Acrylate) is lower than that for commercial semiconductive shield materials. Also, the properties of dispersion showed an increase according to an increase in the ratio of CNT, and the properties were the best at 5 wt%. Therefore, excellent chemical, mechanical and structural properties can be improved with the small amount of CNT.

• Journal of the Korean Ceramic Society
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• v.45 no.9
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• pp.518-523
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• 2008

The mechanical properties of silicon carbide deposited by chemical vapor deposition process onto a graphite substrate are studied using nanoindentation techniques. The silicon carbide coating was fabricated in a chemical vapor deposition process with different microstructures and thicknesses. A nanoindentation technique is preferred because it provides a reliable means to measure the mechanical properties with continuous load-displacement recording. Thus, a detailed nanoindentation study of silicon carbide coatings on graphite structures was conducted using a specialized specimen preparation technique. The mechanical properties of the modulus, hardness and toughness were characterized. Silicon carbide deposited at $1300^{\circ}C$ has the following values: E=316 GPa, H=29 GPa, and $K_c$=9.8 MPa $m^{1/2}$; additionally, silicon carbide deposited at $1350^{\circ}C$ shows E=283 GPa, H=23 GPa, and $K_c$=6.1 MPa $m^{1/2}$. The mechanical properties of two grades of SiC coating with different microstructures and thicknesses are discussed.

• Elastomers and Composites
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• v.45 no.1
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• pp.44-50
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• 2010

The butadiene rubber(BR) blends with chloroprene rubber(CR) were prepared by mechanical mixing method. Cure characteristics, mechanical properties, ozone resistance properties and dynamic mechanical properties were subsequently examined. The properties of ozone resistance of pure BR was significantly improved through blending with 50 wt% CR. Dynamic characteristics determined from a Rheovibron generally showed two glass transition($T_g$) for the entire blends, $tan{\delta}$ peak monotonically shifted toward the higher temperature with the increasing content of CR. Optimum cure time of compound was significantly lengthened with loading of CR.

• Journal of the Korean Wood Science and Technology
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• v.45 no.6
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• pp.703-719
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• 2017

Miscanthus had a higher lignin content (19.5 wt%) and carbohydrate (67.6 wt%) than other herbaceous crops, resulting in higher pellet strength and positive effect on combustion. However, miscanthus also contains a high amount of hydrophobic waxes on its outer surface, cuticula, which limits the pellet quality. The glass transition of lignin and cuticula were related to forming inter-particle bonding, which determined mechanical properties of pellet. To determine the effects of surface waxes, both on the pelletizing process and the pellet strength were compared with raw and extracted samples through solvent extraction. In addition, to clarify the relationship between pellet process parameters and bonding mechanisms, the particle size and temperature are varied while maintaining the moisture content of the materials and the die pressure at constant values. Furthermore, kraft lignin was employed to determine the effect of kraft lignin as an additive in the pellets. As results, the removal of cuticula through ethanol extractions improved the mechanical properties of the pellet by the formation of strong inter-particle interactions. Interestingly, the presence of lignin in miscanthus improves its mechanical properties and decreases friction against the inner die at temperatures above the glass transition temperature ($T_g$) of lignin. Consequently, it could found that the use of kraft lignin as an additive in pellet reduced friction in the inner die upon reaching its glass transition temperature.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.561-562
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• 2006

The effect of chemical composition of the sintering atmosphere on density, microstructure and mechanical properties of Fe-3%Mn-(Cr)-(Mo)-0.3%C steels is described. Pre-alloyed Astaloy CrM and CrL, ferromanganese and graphite were used as the starting powders. Following pressing in a rigid die, compacts were sintered at 1120 and $1250^{\circ}C$ in atmospheres having different $H_2/N_2$ ratio and furnace cooled to room temperature. It has been found that the atmosphere composition has negligible effect on the as-sintered properties of the investigated materials.