• Journal of the Korean Ceramic Society
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• v.38 no.11
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• pp.1008-1014
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• 2001

Nanosize YIG powders added by Cerium which is exellent element in magneto-optical effect were synthesized by Sol-Gel method using Ethylene Glycol solvent. In 120 to 150 minute reaction time, stable sol solution which showed no change in viscosity, pH, and aging time was obtained. Monolithic YIG was synthesized at 80$0^{\circ}C$ with DTA and XRD measurement and its lattice parameter had a tendency to increase from 12.3921 $\AA$. Increasing annealing temperature from 80$0^{\circ}C$ to 105$0^{\circ}C$, average particle size was in the range of 40 nm to 330 nm. Saturation magnetization (M$_{s}$) value was increased from 18.37 to 21.25 emu/g due to enhancement of YIG crystallity and decreasing of orthoferrite phase. On the other hand, coercivity (H$_{c}$) value increased up to 90$0^{\circ}C$ and then decreased above 90$0^{\circ}C$. With increasing Ce addition, coercivity was almost not changed but saturation magnetization value was maximum at Ce 0.1 mol% and then decreased because of increasing a orthoferrite amount. Also, curie temperature (T$_{c}$) of YIG were not changed with Ce addition.ion.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.1
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• pp.97-102
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• 2012

A hermetically sealed oil transformer is designed by applying expanding function of the tank due to the volume changes of the insulation oil according to the temperature rises. When the insulation oil expands, an increase in the volume of the corrugated fin prevents a pressure rise of the transformer. For a wind turbine transformer, a vegetable-oil-immersed transformer has the advantages of excellent biodegradation and fire-resistant properties like an exceptionally high fire point. When vegetable oil is substituted for mineral oil, however, the maximum winding temperature rises because of the decrease in the internal circulation flow rate resulting from the variations of the oil's physical characteristics, such as density and viscosity. The purpose of this study is to develop a hermetically sealed vegetable oil transformer that can be applied in a wind turbine and to analyze the thermal stability of the active part of the transformer to deal with pressure variations due to the temperature changes. In addition, thermal tests for the vegetable oil transformer have been performed, and the measured values are compared with the analysis results.

• Food Science and Preservation
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• v.19 no.3
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• pp.344-353
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• 2012

This study was carried out to investigate the rheological properties of dough and the quality characteristics of breads with Saesalbori (non-waxy barley) and Saechalbori (waxy barley) flours added at concentrations of 10, 20, and 30% to wheat flour. The maximum viscosity increased in the Saesalbori flour mixtures and decreased in the Saechalbori flour mixtures. The dough stability of the 10% barley flour mixtures was equal to that of the control while that of the 30% barley flour mixtures decreased more. The extensibility of the dough decreased with the increasing level of barley flour in all the blends, but the resistance of the dough increased. As the ratio of barley flour increased, the loaf volume of the breads significantly decreased, but the bread weight increased. The 10% Saesalbori flour mixtures increased the hardness of the breads but did not cause any significant change in the other TPA parameters while the 10% Saechalbori flour mixtures did not cause any change in all the TPA parameters. The sensory evaluation results showed that the 10% barley flour mixtures had no significantly different overall acceptance from the control, and that the 20% substitution still resulted in acceptable sensory qualities. The results of the study also showed that the bread-making properties of Saesalbori were improved by germination, but those of Saechalbori declined.

• Journal of the Korean Magnetics Society
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• v.27 no.3
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• pp.92-97
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• 2017

It is widely known that pulsed magnetic field (PMF) is very useful tool to manipulate chemical and physiological processes in human body. The purpose of our study is to observe dynamics of rouleaux patterns of red blood cells (RBC) under PMF. The aggregation of RBCs or rouleaux formation is caused by fibrinogen in blood plasma. The maximum magnetic field intensity is 0.27 T and pulse time of 0.102 msec and pulse repetition rate was 1 Hz. PMF stimulus was applied to the palm of left hand for 5, 10, 15 and 20 min. Live blood analysis was used in vitro in order to quantitatively estimate the velocity of RBC exposed to PMF stimulus. The velocity of stacked-RBC of 10 minute PMF stimulus was increased up to $8{\times}10^{-4}m/sec$, but it decreased rapidly as the time passed. The results of present study have adduced that PMF stimulus on hand provide the improvement of RBC rouleaux formation, increase of RBC's moving velocity as well as low blood viscosity.

• Elastomers and Composites
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• v.47 no.4
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• pp.355-363
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• 2012

A series of poly(hydroxyamide)s (PHAs) having trifluoromethyl group were prepared by direct polycondensation of aromatic diimide-dicarboxylic acids with 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane by thionyl chloride and triethyl amine in N-methyl-2-pyrrolidinone (NMP). The PHAs exhibited inherent viscosity in the range of 0.54-0.96 dL/g at $35^{\circ}C$ in DMAc solution. All PHAs were readily soluble in a variety of organic solvents, whereas the polybenzoxazoles (PBOs) were quite insoluble except partially soluble in sulfuric acid. PHAs were converted to PBOs by thermal cycling reaction with heat of endotherm. The maximum weight loss temperature of the PHAs occurred in the range of $559-567^{\circ}C$. The PBOs showed relatively high char yields in the range of 47-59%. Pyrolysis Combustion Flow Calorimeter (PCFC) results of the PBOs showed 12-19 W/g heat release rate (HRR), and 2.7-3.6 kJ/g total heat release (total HR). The HRR of PBO 1 showed the lowest value of 12 W/g, which was 37% lower than that of PBO 3 (19 W/g).

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.246-254
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• 2004

Physicochemical properties of bread dough added with silkpeptide were investigated. Protein content of silkpeptide was 90.83%. In amino acid analysis, glycine content was highest at 18,760.04 mg%. Alanine, serine, and tyrosine contents were much higher in silkpeptide flour than wheat flour. Mixed silkpeptide showed low lightness and redness values and high yellowness. Farinograph water absorption decreased as silkpeptide content increased. Both arrival and development times of silkpeptide-added dough were longer than those of wheat flour, As silkpeptide content increased, degree of weakness increased, Maximum viscosity of amylograph decreased gradually with addition of silkpeptide, while gelatinization temperature was not affected. Extensograph showed extensibility and resistance to extension of dough increased, while ratio of resistence to extensibility highly increased with increasing amount of silkpeptide. Silkpeptide added to bread dough showed oxidation effect, indication that it could be used as natural additive for improving bread dough quality.

• Journal of the Korean Ceramic Society
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• v.39 no.9
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• pp.871-877
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• 2002

Alumina slurriers, having various amount of alumina and ratio of organic additives, were prepared for tape casting. The relative viscosities were compared to investigate influence of composition on stability of the slurry and plotted as a function of powder fraction. They raised with increasing powder fraction of slurries, revealing a exponential function curve, which means that stability of slurry was not affected by amount and composition of organic additives. Cast green tapes were tested under tensile condition at room temperature. The increase in alumina ratio and binder ratio was found to decrease strain to failure of green tapes from 363% to 45% and from 68% to 25%, respectively. Tensile strength of green tapes increased abruptly with increasing alumina ratio, which showed its maximum at 1 MPa. On other hand, Tensile strength increased continuously from 0.5 MPa to 4 MPa with increasing binder ratio. Mechanical properties of them were affected seriously and lost their properties by elevating temperature from 20$^{\circ}C$ to 80$^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.42 no.6
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• pp.705-713
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• 2010

This study was carried out to investigate the physicochemical properties of bread dough with added mulberry leaf powder. The crude protein, fiber and ash contents of the mulberry leaf powder were 21.25%, 7.70% and 9.27% respectively. The mulberry leaf-mixed powder showed low lightness and redness values and high yellowness. Farinograph water absorption increased as the mulberry leaf powder content increased. Both arrival and development times of the mulberry leaf powder-added dough were longer than those of wheat flour dough. As the mulberry leaf powder content increased, the degree of weakness increased. Maximum viscosity by amylograph analysis increased gradually with the addition of mulberry leaf powder, while gelatinization temperature was not affected. Degree of extension decreased as shown in extensograph analysis with increasing content of mulberry leaf powder.

• Applied Biological Chemistry
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• v.28 no.4
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• pp.219-225
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• 1985

The viscometric properties of six kinds of waxy starches of Olchal and Hankang(waxy rice), Chalborie (waxy barley), Yullmoo (waxy Job's tears), Chajoe (waxy foxtail millet), Chalsusu (waxy great millet) and Chalocsusu (waxy corn) were investigated. The increase in optical transmittance of 0.1% starch suspensions occurred at $55^{\circ}C$ for Hankang, $60^{\circ}C$ for Olchal, Chalborie, Chajoe and Yullmoo and $65^{\circ}C$ for Chalsusu and Chalocsusu, and further inrreased $70^{\circ}C$ for Hankang and Olchal, $75^{\circ}C$ for Chajoe, Chalsusu, Chalocsusu and Yullmoo and above $85^{\circ}C$ for chalborie. Amylogram on 5%, starch suspensions showed that gelatinization temperature and maximum peak height were 850 B.U. at $62^{\circ}C$ for Hankang, $65^{\circ}C$ and 980 B.U. for Olchae, $64^{\circ}C$ and 1,080 B.U. for Chalborie, and 1,410 B.U. at $69^{\circ}C$ for Yullmoo, and 1,280 B.U. at $71^{\circ}C$ for Chajoe, and 1,260 B.U. at $71^{\circ}C$for Chalsusu and 1,420 B.U. at $70^{\circ}C$ for Chalocsusu. Swelling power of starches was $38{\sim}55$, and Hankang, Olchal, Chajoe, Chalocsusu and Yullmoo starches had higher swelling power than Chalsusu and Chalborie starches. Intrinsic viscosity of them was $1.43{\sim}1.75$ and hardness of them highly relevant to the gelatinization properties.

• Journal of the Korean Wood Science and Technology
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• v.37 no.6
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• pp.537-545
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• 2009

The objective of this study was to investigate potential usage of environmentally friendly building materials, liquid mortar and dry cement mortar mixed with charcoal, based on the test of their physical and chemical properties. From the test results of physical and chemical properties of the liquid mortar mixed with charcoal, liquid mortar containing over 20% of charcoal, the consistency viscosity and the non-volatile content met a standard requirement. Drying time was delayed with increase in charcoal contents in the liquid mortar, however they were fully cured within 60 minutes in all treated levels. Other properties were acceptable at standard requirement. From the results, it was found that the proper charcoal addition level to the liquid mortar was 25%. In the results on dry cement, it was found that samples containing 5% of charcoal showed the maximum compressive strength, whereas samples containing over 20% of charcoal did not reach the minimum requirement of KS standard. Water retention ability constantly increased as the charcoal ratio increased. The conventional dry cement mortar adsorbed 59.5% of it, in the test of adsorption rate on ammonia gas, whereas cement mortar containing 10% of charcoal showed 71.6% of ammonia gas adsorption.