• Journal of the Korean Ceramic Society
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• v.41 no.8
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• pp.633-636
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• 2004

The sintering behavior, microstructure and microwave dielectric properties of Ca $Ti_{0.5}$F $e_{0.25}$N $b_{0.25}$ $O_3$ with CuO have been investigated. Among the range of additions, 3 wt％ CuO was observed to perform most satisfactory for acting as a sintering aid. The dielectric properties were found to strongly depend on the sintered densities. The dielectric constant increased with sintering temperatures, while the Q${\times}$ $f_{0}$ value affected by second phase. For Ca $Ti_{0.5}$F $e_{0.25}$N $b_{0.25}$ $O_3$ with 3 wt％ CuO sintered at 100$0^{\circ}C$ for 2 h, the dielectric properties with an $\varepsilon$$_{r}$ value of 56, a Q${\times}$ $f_{0}$ value of 3,500 GHz and a $\tau$$_{f}$ value of 10 ppm/$^{\circ}C$ were obtained and suggested for practical applications.cations.ons.ons.ons.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.122-127
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• 1999

Quality changes of Korean ginseng on microwave drying were determined in terms of water activity, crude protein, crude lipid, crude ash, dielectric properties, content of sugar, ginsenoside composion, microstructure. Korean fresh ginseng were subjected to four different processing : 3 min microwave drying and 2 min holding-24 hrs drying (MWI), 5 min microwave drying and 2.5 min holding-24 hrs drying (MW2), 3 min microwave drying and 2 min holding-12 hrs after hot air drying for 12 hrs drying at $45^{\circ}C$ (MWH1), 5 min microwave drying and 2.5 min holding-12 hrs drying after hot air drying for 12 hrs at $45^{\circ}C$ (MWH2), Water content was decreased 14.33% without shrinkage and water activity was 0.57 after microwave drying. Permittivity was increased as water content increased. As temperature increased, permittivity was increased until $40^{\circ}C$ and fast decreased over $40^{\circ}C$. Content of ginsenoside for MW1 and MW2 was higher than that of MWH1 and MWH2. Data of free sugar showed that there was no significant difference in each treatment. The MW2 dried ginseng showed a more compact structure than the MWH2 ginseng.

• Journal of the Korean Society of Safety
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• v.27 no.1
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• pp.63-69
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• 2012

Ready-mixed concrete(RMC) has been a major construction materials for infrastructures. However, RMC with poor quality is reported to be social issue since it directly user's safety and convenience. Because the properties of concrete as a construction material are greatly influenced by the variation of water content, to control water accurately is the most efficient method for the quality control in RMC industry. In this study, the automatic measurement technology of fine aggregate was developed by using the microwave moisture measurement. For the various conditions of fine aggregate such as moisture, temperature and pressure, the calibration curve of moisture measurement was obtained by using oven-dry method. From the infield and outfield test, it can be obtained that the accuracy of microwave moisture measurement is very high and the automatic system of microwave moisture measurement is very convenient and useful for quality control in RMC Industry.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.173-178
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• 2000

A prototype for a highly sensitive, automated measurement system for the microwave surface resistance of high-T$_c$ superconductor films was set up, and tested by measuring the microwave surface resistances of high-T$_c$ YBa$_2$Cu$_3$O$_{7-{\delta}}$(YBCO) films at the frequency of about 19.6 GHz and the temperature of 30 K ${\sim}$ 90 K. An open-ended TE$_{011}$ mode sapphire-loaded cylindrical cavity resonator was used as the measurement probe, where YBCO films were used as the endplates of the cylindrical cavity. The characteristics of the measurement system include functions to display the unloaded ${\varrho}$ and the resonant frequency of the TE$_{011}$ mode resonator as well as the microwave surface resistance of the YBCO films, all simultaneously as a function of temperature. Applicability of the measurement system for investigating the homogeneity in the microwave properties of large high-T$_c$ superconductor films is discussed.

• Progress in Superconductivity
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• v.2 no.1
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• pp.27-32
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• 2000

A prototype for a highly sensitive, automated measurement system for the microwave surface resistance of high-$T_c$ superconductor films was set up, and tested by measuring the microwave surface resistances of high-$T_c$ $YBa_2Cu_3O_{7-\delta}$ (YBCO) films at the frequency of about 19.6 GHz and the temperature of 30 K $\sim$ 90 K. An open-ended $TE_{011}$ mode sapphire-loaded cylindrical cavity resonator was used as the measurement probe, where YBCO films were used as the endplates of the cylindrical cavity. The characteristics of the measurement system include functions to display the unloaded Q and the resonant frequency of the $TE_{011}$ mode resonator as well as the microwave surface resistance of the YBCO films, all simultaneously as a function of temperature. Applicability of the measurement system for investigating the homogeneity in the microwave properties of large high-$T_c$ superconductor films is discussed.

• Korean journal of food and cookery science
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• v.14 no.4
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• pp.416-420
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• 1998

The Properties of cooked rice prepared by microwave oven was compared with those by pressure cooker There was no significant difference in sensory evaluation between microwave-cooked and pressure-cooked rices, however, the rice cooked by electric cooker was less preferred to others. The hardness of pressure-cooked rice was greater than others. As the storage time for cooked rice increased, the extent of gelatinization decreased, however, there were no significant differences among three samples.

• Journal of the Korean Ceramic Society
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• v.53 no.6
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• pp.707-711
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• 2016

A small diameter of SiC fiber mat can produce much higher heat under microwave irradiation than the other types of SiC materials. Fabrication of high strength SiC fiber consists of iodine vapor curing on polycarbosilane precursor and heat treatment process. The curing stage of polycarbosilane fiber was maintained at $150-200^{\circ}C$ in a vacuum condition under the iodine vapor to fabricate a high thermal radiation SiC fiber. The structure and morphology of the fibers were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TG) and scanning electron microscopy (SEM). In this study, the thermal properties of SiC fiber mats under microwave have been analyzed with an IR thermal camera and its image analyzer. The prepared SiC fiber mats radiated high temperature with extremely high heating rate up to $1100^{\circ}C$ in 30 seconds. The fabricated SiC fiber mats were not oxidized after the heat radiation process under the microwave irradiation.

• Korean Journal of Materials Research
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• v.19 no.12
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• pp.680-685
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• 2009

Using a polyurethane foam replica method, porous hydroxyapatite scaffolds (PHS) were fabricated using conventional and microwave sintering techniques. The microstructure and material properties of the PHS, such as pore size, grain size, relative density and compressive strength, were investigated at different sintering temperatures and holding times to determine the optimal sintering conditions. There were interconnected pores whose sizes ranged between about 300 ${\mu}m$ and 700 ${\mu}m$. At a conventional sintering temperature of 1100$^{\circ}C$, the scaffold had a porous microstructure, which became denser and saw the occurrence of grain growth when the temperature was increased up to 1300$^{\circ}C$. In the case of microwave sintering, even at low sintering temperature and short holding time the microstructure was much denser and had smaller grains. As the holding time of the microwave sintering was increased, higher densification was observed and also the relative density and compressive strength increased. The compressive strength values of PHS were 2.3MPa and 1.8MPa when conventional and microwave sintering was applied at 1300$^{\circ}C$, respectively.

• Proceedings of the Korean Magnestics Society Conference
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• 1991.05a
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• pp.25-26
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• 1991

• Proceedings of the Korean Magnestics Society Conference
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• 1993.11a
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• pp.64-65
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• 1993