• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.1055-1061
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• 2014

Innovative freezing technology is currently applied to preserve foodstuffs for long-term storage. Generally, the quality of frozen food is closely related to the types of freezing and thawing processes. In this study, we characterized the physicochemical properties of onions depending on freezing rate. When onions were frozen at $-40^{\circ}C$, freezing rates were 0.1, 0.5, and $0.7^{\circ}C/min$ depending on air-blast quick freezer mode. Onions were thawed by microwave irradiation at 400 W. Hardness of onion dramatically decreased after freezing and thawing compared with blanched onion. However, the fastest freezing rate did not affect hardness. Thawing loss of onion decreased with a faster freezing rate. For morphological observation, onion frozen at a faster rate showed a smaller ice-crystal size. Vitamin C content decreased upon blanching or freezing, but there was no significant difference according to freezing rate. Although free sugar content also decreased upon blanching and freezing, its highest content was at $0.7^{\circ}C/min$ freezing. Among organic acids, malic acid content was highest at $0.7^{\circ}C/min$ freezing. Based on this study, it could be suggested that a faster freezing rate is effective to improve frozen food quality in accordance with preventing tissue damage or minimizing destruction of nutrients.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.199-209
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• 2010

Coal gasification technology in the sector of domestic clean coal technologies is being into the limelight since recent dramatic rise of international oil price. In this study, we used a low rank coal from Inner Mongolia, China as a starting material for gasification. Various properties including optical, mineralogical, X-ray spectroscopic, X-ray diffraction, and drying property were measured and tested in order to estimate the suitability of the coal to gasification. The coal was identified as a brown coal of lignite group from the measurement of vitrinite reflectance. The coal has very low slagging and fouling potentials, and the ignition temperature is about $250^{\circ}C$. The major impurities consist of quartz, siderite, and clay minerals. Additionally, the coal had moisture content above 28%. Tests for finding effective drying method showed that the microwave drying is more effective than thermal drying.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.3
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• pp.449-454
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• 2010

Extraction characteristics of pumpkin (Cucurbita moschata Duch.) and the functional properties of the corresponding extracts were monitored by the response surface methodology (RSM). The maximum electron donating ability was found as 24.57% at the conditions of 33.13 watt microwave power, 53.67% ethanol concentration and 3.76 min extraction time. The maximum tyrosinase inhibition was 96.59% at 56.21 watt, 68.02% and 7.97 min. The SOD-like activity was 45.57% at 36.00 watt, 71.51% and 5.28 min. The total polyphenol content was 85.02% at 127.39 watt, 76.18% and 2.68 min. Based on superimposition of four dimensional RSM with respect to electron donating ability, tyrosinase inhibition, SOD-like activity and total polyphenol contents obtained under the various extraction conditions, the optimum ranges of extraction conditions were found to be microwave power of 72~144 watt, ethanol concentration of 0~38% and extraction time of 6~9 min.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.3
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• pp.435-442
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• 2010

This study was to investigate the quality characteristics of instant rice cake (Baekseolgi) with different concentrations of ginseng powder by molecular press dehydration (MPD) method. Baekseolgi was cooked using microwave oven, which is a useful cooking method because of reduced cooking time, even though it quickly takes moisture from food surface and lowers food quality. The result indicated that moisture content of Baekseolgi without ginseng powder was decreased; however, there was no significant difference in the Baekseolgi with ginseng powder with increased storage time for 24 hrs. The L value was decreased and a color value was increased with increasing concentrations of ginseng powder (p<0.05). There was no significant difference in the color values within the storage time. The hardness, gumminess, and chewiness of Baekseolgi without ginseng powder significantly changed as the storage time increased; in contrast, those of Baekseolgi with ginseng powder did not show such a significant change. The result of sensory evaluation showed that Baekseolgi with ginseng powder has higher scores in terms of color, flavor, taste, and overall acceptability than Baekseolgi without ginseng powder. Results of this study indicate the addition of ginseng powder to Baekseolgi improves moisture content, color value, and texture properties as well as sensory characteristics.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.476-481
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• 2013

Ethylbenzene (EB) which has a similar physical properties with p-xylene (pX) was separated from EB/pX mixture by using MFI-type zeolite (TS-1, ZSM-5, and Silicalite-1) coated membranes. The zeolites were synthesized by microwave method to reduce the synthesis time and uniformly formed zeolite particles were coated on the ${\alpha}$-almina tubular support with a thickness of $3-4{\mu}m$. Separation factor and permeation flux of the synthesized zeolite coated membranes were measured to survey the best performance of ethylbenzene separation from different composition of EB/pX mixtures. When the EB/pX mixture of 5:5 molar ratio applied for the separation experiment, it represented the highest separation factor. We also have studied about the effect of the atomic composition of zeolites on the separation performance within the temperature range from 160 to $220^{\circ}C$. TS-1 showed the highest permeation flux of $1,666mol/m^{2*}s^*Pa$ and Silicate-1 showed the highest separation factor of 1.73 at $200^{\circ}C$ respectively.

• Food Science and Preservation
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• v.20 no.6
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• pp.810-817
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• 2013

This study investigated the properties of rice snack puffed in a microwave oven after drying its dough according to Baekjinju soaking time and additional soybean milk. The optimum conditions for the non-fried rice snack using Baekjinju wetted flour were determined through the design of an experiment using response surface methodology. The independent variables were the Baekjinju soaking time and the additional soybean milk, and the dependent variables were the weight, volume, density, expansibility, Hunter's color value, hardness, and sensory properties. The quadratic model was chosen for the weight, density, expansibility, b value, and hardness. The two-factor interaction model was chosen for the volume, flavor, appearance, and overall preference. The linear model was chosen for the L value, taste, and texture. The weight was increased to longer than 11.26 days with the increase in the rice soaking. The volume, expansibility, L value, and b value increased with the increase in the rice soaking time and in the additional soybean milk ratio. However, the density was decreased was in reverse. The hardness increased most, with the rice soaking time rising from 5.28 to 8.53 days and the soybean milk additional ratio increasing from 5.34 to 20.26%. The sensory properties improved as rice soaking time decreased, and the soybean milk additional ratio was revered. As for the desirability, the optimal formulation of the dough of non-fried rice snack was achieved by mixing 200 g of Baekjinju flour with a 0.69 days rice soaking time and a 26.67% soybean milk of rice ratio according to weight.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.771-777
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• 2017

This study investigated the rheological properties of Calrose rice flour dispersions as well as the effects of different thawing methods (steamer, smart oven, and microwave oven) on quality characteristics of frozen turmeric rice. Apparent viscosity, consistency index, and yield stress significantly increased at higher rice flour concentrations. Magnitudes of storage modulus and loss modulus significantly increased with elevation of rice flour concentration. Frozen turmeric rice thawed using a steamer had the highest moisture content and largest size (length, width, and thickness) among all thawing methods. The L values of turmeric rice after thawing using a steamer was significantly higher than those of other thawing methods. The a value of turmeric rice after thawing using a steamer was significantly lower than those of other thawing methods. Textural properties (hardness, adhesiveness, springiness, cohesiveness, brittleness, and chewiness) of frozen turmeric rice after thawing using a steamer were significantly lower than those of other thawing methods. Therefore, it can be concluded that frozen turmeric rice after thawing using a steamer might be desirable for improvement of texture.

• Journal of the Korean Ceramic Society
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• v.42 no.2 s.273
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• pp.132-139
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• 2005

Sintering behavior of $BaO-Nd_{2}O_3-TiO_2$ with a Pb-based glassceramics frit were investigated in order to understand an effect of glassceramics as a low temperature sintering agent on dielectric ceramics. A green sheet form was fabricated through tape casting method with the glassceramic fut added $BaO-Nd_{2}O_3-TiO_2$. The dispersion properties, rheological properties and final density of dielectric composit slurry as a function of amount and composition of organic additives was examined. The dispersants' addition was effective in controlling dispersion of the ceramics in solution. The addition of excessive dispersant showed adverse effect on dispersion. The prepared slurries, containing ceramic : powders, glass-ceramics and various kinds of organic viechles, exhibited typical shear thinning behavior. The best properties of tape casting appeared powder to solvent ratio 65 : 35 and amount of the binder 6 wt$\%$ and plasticizer 3 wt$\%$. The viscosity of the slurry was 677 cps and green/sintered density in the tape was $3.3 g/cm^3,\;5.56 g/cm^3$ respectively.

• Korean Journal of Materials Research
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• v.18 no.4
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• pp.169-174
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• 2008

The structural and electrical properties of amorphous $BaSm_2Ti_4O_{12}$ (BSmT) films on a $TiN/SiO_2/Si$ substrate deposited using a RF magnetron sputtering method were investigated. The deposition of BSmT films was carried out at $300^{\circ}C$ in a mixed oxygen and argon ($O_2$ : Ar = 1 : 4) atmosphere with a total pressure of 8.0 mTorr. In particular, a 45 nm-thick amorphous BSmT film exhibited a high capacitance density and low dissipation factor of $7.60\;fF/{\mu}m2$ and 1.3%, respectively, with a dielectric constant of 38 at 100 kHz. Its capacitance showed very little change, even in GHz ranges from 1.0 GHz to 6.0 GHz. The quality factor of the BSmT film was as high as 67 at 6 GHz. The leakage current density of the BSmT film was also very low, at approximately $5.11\;nA/cm^2$ at 2 V; its conduction mechanism was explained by the the Poole-Frenkel emission. The quadratic voltage coefficient of capacitance of the BSmT film was approximately $698\;ppm/V^2$, which is higher than the required value (<$100\;ppm/V^2$) for RF application. This could be reduced by improving the process condition. The temperature coefficient of capacitance of the film was low at nearly $296\;ppm/^{\circ}C$ at 100 kHz. Therefore, amorphous BSmT grown on a TiN substrate is a viable candidate material for a metal-insulator-metal capacitor.

• Journal of the Korean Vacuum Society
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• v.9 no.3
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• pp.227-232
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• 2000

$MgTiO_3$thin films have been grown on various substrates by pulsed laser deposition (PLD) to investigate the application for microwave dielectrics and optical devices. Epitaxial $MgTiO_3$thin films were obtained on sapphire (c-plane$A1_2O_3$$MgTiO_3$thin films deposited on $SiO_2/Si$ and platinized silicon ($Pt/Ti/SiO_2/Si$) substrates were highly oriented. $MgTiO_3$thin films grown on sapphire were transparent in the visible and had a sharp absorption edge about 290 nm. These $MgTiO_3$thin films had extremely fine feature of surface morphology, i.e., rms roughness of 0.87 nm, which was examined by AFM. We have investigated the dielectric properties of the $MgTiO_3$thin films in $MIM(Pt/MgTiO_3/Pt)$ capacitors. Dielectric constant and loss of $MgTiO_3$thin films deposited by PLD were about 24 and 1.5% at 1 MHz, respectively. These $MgTiO_3$thin films also exhibited little dielectric dispersion.