• Korean Journal of Plant Resources
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• v.33 no.1
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• pp.50-61
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• 2020

Pigeon pea (Cajanus cajan) is an important legume species that produces seeds that are rich in phenolic compounds and dietary nutrients. The aim of the present study was to evaluate the agricultural characters, phenolic and nutritional contents, and antioxidant capacities of seeds from 82 pigeon pea germplasms cultivated in the Republic of Korea. The accessions exhibited compact (24.39%), semi-spreading (74.39%), or spreading (1.22%) growth habits and determinate (89.02%), indeterminate (8.54%), or semi-determinate (2.44%) flowering patterns. Days to 75% maturity ranged from 30 to 72 d, and yield per plant ranged from 6.00 to 148.60 g. Meanwhile, total phenolic, crude protein, crude fiber, and dietary fiber contents ranged from 16.42 ± 0.62 to 29.67 ± 0.43 mg gallic acid equivalent per g of dried extract, from 16.76 ± 6.74% to 22.61 ± 0.05%, from 4.70 ± 0.24 to 8.63 ± 0.02%, and from 12.98 ± 0.71 to 33.19 ± 1.50%, respectively. In addition, DPPH radical-scavenging capacity ranged from 1.61 ± 0.10 to 16.04 ± 2.30 mg ascorbic acid equivalent per g of dried extract, and Trolox equivalent antioxidant capacity ranged from 3.03 ± 0.86 to 42.24 ± 0.72 mg Trolox equivalent per g of dried extract. Phenolic content was correlated with both DPPH radical-scavenging capacity (r = 0.63) and Trolox equivalent antioxidant capacity (r = 0.29). Nine accessions (IT170290, IT170291, IT170270, IT170276, IT170379, IT170386, IT170388, IT170418, and IT170340) exhibited early maturity, compact and erect growth habits, and above average antioxidant activities and phenolic and protein contents. In addition, accessions IT170290 and IT170291 were especially promising pigeon pea germplasms to grow, owing to various favorable characteristics (e.g., high yield and dietary fiber content). Hence, these accessions could be useful cultivars to the Republic of Korea if considered in future agricultural systems.

• Preventive Nutrition and Food Science
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• v.15 no.3
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• pp.221-228
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• 2010

The objective of this research was to investigate the changes in the contents of physicochemical properties including $\gamma$-aminobutyric acid (GABA), total dietary fiber (TDF), amylose, protein, and fat content in brown rice through germination for 2 different years. Total phenolic contents and antioxidant activities of DPPH and ABTS radical scavenging capacities were also determined in different solvent extracts. For the physicochemical properties, GABA, TDF, protein, and fat content increased, whereas amylose levels decreased. Specially, GABA and TDF levels showed the greatest variations among cultivars and harvest years. Total phenolic content and antioxidant activity significantly increased. The average total phenolic content at a concentration of 0.5 mg/mL in different extract solvents occurred in this order: methanol>ethylacetate>chloroform>hexane extracts. Additionally, 'Keunnun' exhibited the highest GABA levels, highest total phenolic content, and highest antioxidant activity after germination, with increases of approximately 3.7, 2.0, and 1.9 times, respectively, compared to levels before germination. These results suggest that, because of its high physicochemical contents and strong radical scavenging activities, germinated brown rice can be used as beneficial supplement.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.92-100
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• 1999

Friction characteristics of automotive friction materials according to the types of phenolic resin were investigated by using a pad-on-disk type friction tester. Four different simplified friction materials bound with Bakelite$^{TM}$ and Xylok$^{TM}$ phenolic resin were studied in this work. Two different modes of drag test(constant initial temperature test and constant interval test) were employed to analyze the effects of the binders on friction characteristics. Friction materials containing modified Xylok$^{TM}$ resin showed good heat resistance and friction stability. The results also showed that aramid fiber played important roles in improving friction stability and weard wear

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.55-58
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• 2004

Phenolin resin, prepared form phenol and formaldehyde, is one of the oldest thermosetting resins available. Phenolic resins are cured via condensation polymerization with evolution of water, which in molding process is a big problem. The use of phenolic resins in glass fiber composites is growing, primarily due to their low flame spread, low smoke generation and low smoke toxicity properties. SMC of phenolics has been rearched since the 1986. The technology challenge was to match resin viscosity, handling and cure with those for the polyester SMC to avoid any special processing for fabricators and end users. Phenolic SMC was chosen because of the ease of molding to the required shape with light- weight, thin wall structure and with excellent fire protection.

• Korean Journal of Plant Resources
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• v.34 no.6
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• pp.527-535
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• 2021

Legumes have been important components of the human diet. They contain not only protein, starch, and dietary fiber, but also various phenolic compounds such as flavonoids and phenolic acids. The importance of phenolic compounds to human health is well known due to their antioxidant activities. In this study, three legumes (adzuki beans, common beans, and black soybeans) frequently cultivated in Korea were evaluated for their total phenolic content (TPC) and antioxidant activities using DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azinobis (3-ethylbenzothiazoline 6-sulfonate)), and FRAP (ferric reducing antioxidant potential) assays. In addition, correlations between agricultural traits and antioxidant activities of these three legumes were analyzed. Antioxidant activities assessed by DPPH, ABTS, and FRAP assays and TPC showed wide variations among legumes types and accessions. Among the three legumes, adzuki beans showed higher TPC and antioxidant activity than the other two legumes. In correlation analysis, seed size showed negative correlations with antioxidant activities and TPC. In principal component analysis and hierarchical clustering analysis, each of the three legumes was clearly separate. Results of this study can be used as basic information for developing functional materials for each legume. They can also help us understand the overall antioxidant activity of the three legumes.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.18-25
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• 2003

In this paper, thermal conductivities of carbon-phenolic 8-harness satin weave composite, ACP302, were measured and predicted. In the analysis, the satin weave unit cell was identified and modeled discretely by 3-dimensional finite elements, considering the interlaced fiber tow architecture microscopically. At the unit cell boundary, the corresponding periodic boundary conditions were applied. The results were analyzed to investigate the effect of microstructural parameters such as stacking phase shifts, waviness ratio, and fiber volume fraction. The conductivities were also obtained by experiments and compared with the numerical results.

• Korean Journal of Materials Research
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• v.4 no.3
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• pp.339-348
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• 1994

The study has been conducted to know ablation microstructures and characteristics in carbon /phenolic composites. Ablation properties depend on mole fraction of $H_2O$ and $C0_2$ gas which were produced by reaction between propellant and oxidizer. However, the results of this study shown that the ablation also depended on weaving structure, density of fabric, and tow size of carbon fiber. 3K 8HS fabric showed superior ablation resistance to others, 3K twill and 12K 8HS fabric structures.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.31-35
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• 2006

Degradation characteristics of filament-winded composites due to accelerated environmental aging have been evaluated under high temperature, water immersion and thermal impact conditions. Two kinds of laminated composites coated by an urethane resin have been used: carbon-fiber reinforced epoxy(T700/Epon-826, CFRP) and glass-fiber reinforced phenolic (E-glass/phenolic, GFRP). For tensile strength of $0^{\circ}$ composites, CFRP did high reduction by 25% under the influence of high temperature and water while CFRP showed little degradation. However for water-immersed $90^{\circ}$ composites both CFRP and GFRP showed high reduction in tensile strength. Bending strength and modulus of $90^{\circ}$ composites were largely reduced in water-immersion as well as high temperature environment. Urethane coating on the composite surface improved the bending properties by 20%, however hardly showed such improvement for water-immersed $90^{\circ}$ composites.

• Carbon letters
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• v.1 no.3_4
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• pp.133-137
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• 2001

Mesoporous activated carbon fiber (ACF) was prepared from phenolic resin containing a small amount (0.1 wt %) of organic nickel complex through carbonization and steam activation. Microporous ACF as reference sample was also prepared from phenolic resin without agent. In both cases of the mesoporous ACFs and the microporous ACFs, the electric double layer capacitance of the nonaqueous electrolyte (0.5 M $TEABF_4$/PC or 1.0 M $LiClO_4$/PC) was not proportional to the BET specific surface area. This is owing to the low permeability of nonaqueous electrolyte or the low mobility of ion in narrow micropores. However, the mesoporous ACF showed higher double layer capacitance than the microporous (normal) ACF. This result suggests that the presence of many mesopores promotes the formation of effective double layer or the transfer of ion in the micropore.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.391-396
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• 2005

Salt water spray test and salt water immersion test were experimentally conducted in order to investigate the durability of fiber reinforced composites under salt water environment. The specimens were made of glass fabric reinforcement and phenolic resin. Mechanical test was performed to obtain mechanical properties such as tensile properties, flexural properties, and shear properties by varying with exposure times. Also dynamic mechanical test and FTIR were conducted to investigate a change in chemical structure as well as thermal analysis properties such as storage shear modulus, loss shear moduls, and tan ${\delta}$. According to the results, salt water environment has effected on mechanical properties and thermal analysis properties and especially the durability of glass fabric/phenolic composites were severely affected on salt water immersion environment rather than salt water spray environment.