• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.792-797
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• 2010

Microwave oven and household cooker are devices of high voltage producer and high voltage storage batteries respectively for formation of necessary high frequencies at drive. These devices emit much heat energy because they are run at high voltages. Therefore, emitted heat energy becomes a factor that raises temperature of microwave ovens' main frame. In this research, the analysis shows the temperature distribution in microwave oven with the cooling fan drive conditions and the heat energy occurrence conditions. According to the analysis, as the speed of air outpoured in cooling fan increases, and the internal temperature decreases quantitatively. Also the inside temperature distribution was investigated by controlling heat energy emission.

• Biomedical Science Letters
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• v.13 no.4
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• pp.361-368
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• 2007

Biological samples can be fixed either by chemical method by using chemical solution or physical methods by using heat treatment. The problem in traditional heat fixation is unsatisfactory quality due to uneven heat conduction in specimen and loss of inner cell contents. Chemical fixation method also bears several intrinsic problems like the limit in specimen size, time consumption in fixative impregnation, and loss of low molecular weight cell components. These factors deteriorate the quality of fixed specimen, thus limit the magnification and contrast of tissue pictures. Microwave heat has been reported to be a good alternative to current chemical methods to overcome these problem. In this study, we tried to introduce the microwave energy method to routine fixation work in hospital. We replaced chemical fixative with saline to provide moderate reaction condition, and used frozen section to reduce time for sample preparation. Temperature was measured at each experiment. The fixation of rat kidney tissue with 2.45 GHz electromagnetic wave and saline showed similar result to the control group fixed with traditional chemical method. Human tumor tissue fixed with 2.45 GHz electromagnetic in frozen section was improved in terms of histochemistry of PAS and immunohistochemistry of tumor marker like cytokeratin. Total turnaround time was reduced from $24\sim38$ h to to $2\sim4$ h. In conclusion, the quality of samples prepared by microwave heating method was at least as good as that of traditional method. If the condition for the fixation of different specimens is standardized, this new method could be applied to routine work in hospital, and could save working time as well.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.3
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• pp.133-138
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• 2020

As HMR (home meal replacement) food market grows rapidly, a new packaging with more HMR specialized functions is highly required to promote consumers' convenience. A susceptor is defined as a material generating heat by absorbing electromagnetic energy such typically as radiofrequency or microwave radiation. In microwave cooking, susceptors are made of conductive metal thin film deposited on paper or plastic sheet and have generally been used to help crispen or brown foods by converting microwave energy into heat. This mini review article deals with current status of microwave susceptor packaging including commercial products, technical theory, types of susceptor and a test method for heating performance.

• Journal of the Korean Ceramic Society
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• v.56 no.6
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• pp.583-588
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• 2019

Silicon carbide (SiC) fiber mats generate large amounts of heat through microwave interactions and are used as heating elements in rapid heat treatment furnaces. However, SiC fibers cool immediately when the microwave power is turned off. Therefore, ceramic layers are inserted between the SiC fiber layers to improve the heat conservation performance of SiC fiber mats. In this study, we fabricated SiC fiber mat composites (SMCs) with ceramic layers under various pressures. The SMC fabricated under 0.007 kPa showed the lowest heat-generating temperature and deviation because less necking was observed between the materials. On the other hand, the SMC fabricated under 0.375 kPa showed the highest heat-generating temperature of 1532.33℃. The SMCs prepared in this study using ceramic powder not only showed heat-generating temperatures comparable to those of conventional SiC fiber mats but also exhibited excellent heat-preserving ability.

• Journal of the Korean Ceramic Society
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• v.50 no.1
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• pp.70-74
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• 2013

Dependence of microwave dielectric properties on the crystallization behaviors of $CaMgSi_2O_6$ (diopside) glass-ceramics was investigated with different heat treatment methods (one and/or two-step). The crystallization behaviors of the specimens, crystallite size and degree of crystallization, were evaluated by differential thermal analysis (DTA), scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis by combined Rietveld and reference intensity ratio (RIR) methods. With an increase in heattreatment temperature, the dielectric constant (K) and the quality factor (Qf) increased due to the increase of the crystallite size and degree of crystallization. The specimens heat-treated by the two-step method had a higher degree of crystallization than the specimens heat-treated by the one-step method, which induced improvement in the quality factor (Qf) of the specimens.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.44-47
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• 1998

A reduction/oxidation reaction between A1 metal powder and SiO2 powder was performed by Self-propagating High-temperature Synthesis (SHS) reaction induced by microwave energy to produce a composite of Al2O3 and Si powders by using a 2.45 GHz kitchen model microwave oven. A Microwave Hybrid Heating(MHH) method was applied by using SiC powders as a suscepting material to raise the temperature of the disk samples and the heat increase rate of over 100℃/min were obtained before the reaction. The reaction started around 850℃ and the heat increase rate jumped to over 200℃/min after the reaction took place.

• 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.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.114-117
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• 2003

Conventional heating the heat source cause the molecules to react from the surface toward the center so that successive layers of molecules heat in turn. The product surfaces may be in danger of over heating by the time heat penetrates the material. Microwave, however, produce a volume heating effect. All molecules are set in action at the same time. It also evens temperature gradients and offers other important benefits such as selective heating. (omitted)

• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.144-149
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• 2004

Changes in functional constituents of grape (Vitis vinifera) seeds prepared by three different heat pretreatments were determined and compared with those of non-treated grape seed. The recovery of grape seed oils was generally increased by roasting, steaming and microwave processes, although the recovery of specific constituents varied among three heat pretreatments. The recovery of MeOH extracts of the seeds increased following the roasting process, whereas that of MeOH extracts decreased gradually with steaming and microwave treatments. Levels of four catechins in grape seeds: (+)-catechin, procyanidin B$_2$, (-)-epicatechin, and (-)-epicatechin gallate, were decreased with increased roasting and steaming time, but were unaffected by microwave treatment. During the three different heat pretreatments, levels and compositions of fatty acid did not change, whereas those of phytosterol compositions decreased greatly. These results suggest that a mild heat pretreatment, controlled for temperature and time, is needed to prevent a considerable loss in the level of valuable functional components in grape seed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.3
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• pp.258-263
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• 2000

Effect of microwave heat-treatment processing on the electrical conductivity and crystallization behavior for the $Li_2O-2SiO_2$-xCuO glasses with various CuO contents was compared with that of conventional heat-treatment processing. The electrical conductivities of samples heat-treated at $500^{\circ}C$ by different heat-treatment processing were increased with increasing CuO content and higher electrical conductivities were obtained from microwave heat-treated samples. From the result of XRD analyses, microwave heat-treatment processing enhanced the degree of crystallization in the formation of $Li_2Si_2O_5, Li_2Cu_5$($Si_2O_7)_2$, and $Li_2Cu_2O_3$ crystalline phases. The electrical conductivities of $Li_2O-2SiO_2$-1.3CuO (30 mol% CuO) glass heat-treated at $500^{\circ}C$ for 30 min under conventional and microwave heat-treatment processing were $0.11{\times}10^{-4}(\Omega \textrm {cm})^{-1}$ and $0.68{\times}10^{-4}(\Omega \textrm {cm})^{-1}$ at room temperature, respectively. It was speculated that microwave energy enhanced the degree of crystallization and increased electrical conductivity in the samples.