• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.6
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• pp.269-273
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• 2001

The effect of $TiO_2$addition on the hydration reaction of MgO ceramics were studied after being heated at $1450^{\circ}C$. The pure MgO ceramics showed significant weight change after exposure to water due to the hydration reaction through the formation of $Mg(OH)_2$while $TiO_2$-added MgO ceramics did not. The $Mg_2TiO_4$phase were observed in the $TiO_2$-added MgO ceramics sintered at 145$0^{\circ}C$. Bulk density increased as the amount of $TiO_2$increased and the apparent porosity and water absorption decreased by $TiO_2$addition. The hydration resistance of MgO ceramics was found to be improved by $TiO_2$addition.

• Analytical Science and Technology
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• v.20 no.2
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• pp.176-182
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• 2007

The present study relates to a matrix-typed, sustained-releasing agent comprising agrochemical effective ingredients being capable of recognizing a content of moisture, and a preparation method thereof. The curdlan solution added to acid was formed matrix which has unique network structure. The matrix treated by heat lost water solubility. The network structure of matrix was opened in the aquatic condition but closed again in dry condition. Therefore, in the sustained-releasing formulation system, an agrochemical effective ingredient was released from the formulation only in the aquatic condition. Use of the composition according to the product can control a manifesting time of effects of agrochemicals and can provide agrochemicals with reduced harmful damages.

• Korean Journal of Food Science and Technology
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• v.45 no.1
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• pp.34-39
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• 2013

This study was performed to investigate the antioxidant activity of mung beans with heat treatment at $130^{\circ}C$ for 2 h after acid hydrolysis. The browning index of heating after hydrolysis was 2.31 whereas heating before hydrolysis was 0.17. 5-hydromethyl-2-furaldehyde (5'-HMF) content was the highest value of 81.61 mg/g in heating after hydrolysis. The highest total polyphenol content (55.95 mg/g) occurred in heating after hydrolysis and this value was 6.4-fold higher than that of heating before hydrolysis (8.79 mg/g). 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity was the highest value of 22.19 mg AA eq/g sample in heating after hydrolysis whereas heating before hydrolysis was 1.75 mg AA eq/g sample.1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity was the highest value of 3.64 mg Trolox eq/g sample in heating after hydrolysis whereas heating before hydrolysis was not shown. These results suggest that heat treatment of mung beans for increasing the antioxidant activity could be effective after hydrolysis.

• Food Science and Preservation
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• v.12 no.2
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• pp.161-165
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• 2005

The content of general components such as moisture, crude ash, protein and crude fat were not different among the samples, but the content of crude protein in the fresh garlic was higher (in fresh garlic) than that of heat-treated garlic. Eighteen amino acids were analysed from the fresh garlic. The content of arginine was the highest in the fresh garlic. The amount of free amino acids was less than that of total amino acids, but their compositions were similar. Among minerals, the content of K was much higher than those of Mg, Ca and Na. The volatile compounds from the garlic extracts were identified by GC/MS. The composition of diallyl disulfides was very high among the volatile compounds, which were decreased in heat-treated ones.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.330-339
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• 2009

The material properties of Cedar (Cryptomeria japonica) were evaluated according to heat treatment conditions. The special focus was made on the color control of cedar wood by heat treatment. The difference of color between sapwood and heartwood could be reduced by heat treatment at a temperature above $170^{\circ}C$. Long heating time was more effective in reducing the difference. The Equilibrium Moisture Content (EMC) of heat-treated wood was as low as 50 percent. The result obviously indicates that heat-treated wood is more dimensionally stable in the change of moisture condition than the control. The heat-treated wood was also effective in increasing the durability against wood rotting fungi. However, more study is required to develop heat treatment as an environmentally-friendly technology for wood preservation without chemical. The mechanical properties of heat-treated wood showed relatively higher performance than the control in general. Meanwhile the dramatic decrease in impact bending stress due to the loss of ductility may limit uses of heat-treated wood in certain cases. There were no significant changes in microscopic structure which may cause changes in mechanical properties. Further study on the chemical analysis of heat-treated wood is needed to scrutinize the causes of changes of material properties.

• Journal of the Korean Wood Science and Technology
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• v.38 no.1
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• pp.17-26
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• 2010

Recently, yellow poplar (Liriodendron tulipifera L.) is getting attention in Korea due to the fast growing and high yield and quality of lumber. But, it is thought that the color difference between heartwood and sapwood may restrict the practical use of it. This study was aimed to enhance the value of yellow poplar lumber by the color control using high temperature heat-treatment, which had been tried for domestic cedar (Kim et al., 2009). The material properties including surface color of yellow poplar lumber were evaluated according to heat treatment conditions. The difference of color between sapwood and heartwood could be reduced by heat treatment at a temperature about $200^{\circ}C$. Long heating time was more effective in reducing the difference. The Equilibrium Moisture Content (EMC) of heat-treated wood was as low as 50 percent of the control. The result obviously indicates that heat-treated wood is more dimensionally stable in the change of moisture condition. The durability against wood rotting fungi also increased by the heat-treated, but it was not so effective as the case of cedar. The changes of mechanical properties of heat-treated yellow poplar were very similar to that of heat-treated cedar. In order to develop new use of heat-treated yellow poplar, the changes of mechanical properties should be considered. There were no significant changes in microscopic structure which may cause changes in mechanical properties. Further study of heat-treated wood is needed to scrutinize the causes of changes of material properties.

• Korean Journal of Materials Research
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• v.8 no.4
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• pp.317-322
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• 1998

The stabilization of low dielectric constant SiOF films prepared by conventional PECVD using TEOS and $C_2F_6$ was evaluated by the $N_2O$-plasma post-deposition annealing. Properties of SiOF film became unstable when it was air-exposed or heat-treated. Water absorption of SiOF films was increased as F content was increased due to the for¬mation of F -Si- F bonds. Also F content of SiOF films decreased after heat treatment. $N_2O$-plasma post-deposition annealing was proved to be effective on stabilizing SiOF films. which was mainly due to the formation of thin SiON layer near the top surface of films. However. the value of dielectric constant was greatly increased again when $N_2O$-plasma post-deposition annealing was done for a long time. To stabilize the SiOF films without an increase of dielec¬tric constant by $N_2O$- plasma post-deposition annealing. the annealing time should be kept the minimum value. to which stabilizing effects against air environment and heat treatment were preserved.

• Korean journal of applied entomology
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• v.48 no.1
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• pp.109-115
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• 2009

The thermal stability and mechanical properties of Nephila clavata and Bassaniana decorata spider silks were measured and compared with those of aramid and polyester fibers. The thermal stability of the spider silk was lower than those of the commercial aramid and polyester fibers. However, the mechanical properties of the spider silk were far superior to that of the polyester fiber. The effect of the water content of the spider silk on its thermal stability and mechanical property was examined by conducting the silk to heat treatment at $100^{\circ}C$ under vacuum for various times. The results indicated that spider silk subjected to heat treatment for 1.5 hr had excellent thermal stability and mechanical property.

• Journal of the Korean Society for Heat Treatment
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• v.23 no.5
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• pp.249-256
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• 2010

Water jet impingement cooling has been widely used in a various engineering applications; especially in cooling of hot steel plate of steelmaking processes and heat treatment in hot metals as an effective method of removing high heat flux. The effects of cooling water temperature on water jet impingement cooling are primarily investigated for hot steel plate cooling applications in this study. The local heat flux measurements are introduced by a novel experimental technique that has a function of high-temperature heat flux gauge in which test block assemblies are used to measure the heat flux distribution during water jet impingement cooling. The experiments are performed at fixed flow rate and fixed nozzle-to-target spacing. The results show that effects of cooling water temperature on the characteristics of jet impingement heat transfer are presented for five different water temperatures ranged from 5 to $45^{\circ}C$. The local heat flux curves and heat transfer coefficients are also provided with respect to different boiling regimes.

• Food Science and Preservation
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• v.21 no.6
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• pp.784-789
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• 2014

This work aimed to investigate the changes in the nutrient contents and antioxidant activity of Peucedanum japonicum Thunb. by ripening stage, growing condition, and blanching. The crude protein content of the young leaves (3.6~4.3%) was higher than that of the mature leaves (3.1~3.9%). Higher calcium contents were observed in the greenhouse-cultivated samples (225.9~259.2 mg/100 g) compared to the field-cultivated samples (178.5~199.5 mg/100 g). The vitamin C and folate contents (18.1~83.8 and 175.8~220.2 mg/100 g, respectively) of the field-cultivated samples were significantly (p<0.05) higher than those of the greenhouse-cultivated samples (13.1~57.7 and 133.0~148.8 mg/100 g, respectively). The growing condition and blanching were significant factors affecting the changes in the vitamin and polyphenol contents. The ${\beta}$ carotene contents of the blanched samples increased 2.6-fold compared to those of the raw samples. The total polyphenol contents (10.2~17.1 mg/g extract) and DPPH radical scavenging activity ($IC_{50}=2.0{\sim}3.0mg/ml$) of the blanched samples were significantly (p<0.05) higher than those of the raw samples (1.8~4.3 and $IC_{50}=16.2{\sim}21.1mg/ml$, respectively).