• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.2210-2212
• /
• 2000

전자레인지는 전자파를 발생시키는 마그네트론과 도파관 캐비티로 이루어진다. 캐비티는 전자파의 측면으로 볼 때 일종의 공진기로 작용한다. 그러므로 전자파가 강한 곳과 약한곳이 나타나게 된다. 이런 배경에서 전자레인지의 주요 설계 기술 중의 하나는 캐비티내와 전자파의 분포를 균일하게 만드는 기술이다. 그러나 전자레인지는 제품의 특성상 여러 가지 다양한 부하가 캐비티의 내부에 분포하게 되기 때문에 부하에 따른 캐비티 내부의 전자파 분포를 균일하게 하는 것은 매우 중요한 기술로 된다. 따라서 본 논문에서는 이러한 여러 가지 조건에서 캐비티내의 전자파의 분포를 분석 할 수 있는 측정 방법과 설계 인자를 추출할 수 있는 방법을 제안하였다. 또한 전자파의 분포를 측정한 결과의 정확성을 고찰하기 위하여 캐비티내의 mode 해석을 이용한 modeling을 제안하였으며 측정과 비교 검토를 수행하였다. 그 결과 캐비티내의 전자파의 분포를 전송선 이론을 이용한 분석에 의해 설계 가능하고 또한 보정 가능함을 보였다.

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

• Food Science and Preservation
• /
• v.14 no.3
• /
• pp.227-232
• /
• 2007

The development of an effective long-term storage protocol for harvested fresh pepper is urgently required to increase the market for pepper products. The protocol must minimize quality loss, so that the product may be used either as a spice or as a raw material for processed pepper products, both in the home and in food processing plants. We investigated the optimum size of pepper fruits, freezing temperatures, storage periods, and thawing methods, to establish an optimum storage protocol. This study was conducted not only to develop freezing and thawing methods for long term storage of harvested red pepper, but also to develop processed pepper products utilizing the stored pepper. We aimed to expand the pepper products market and to increase the incomes of pepper growers. Whole red pepper, sliced red pepper, and crushed red pepper were frozen and stored at $-5^{\circ}C,\;-20^{\circ}C,\;or\;-40^{\circ}C$. The soluble solid content and the vitamin C level showed maximal stability at $-40^{\circ}C$, although total free sugars decreased on storage at all temperatures tested. Such Changes were more marked at $-5^{\circ}C$ than at the other(lower) temperature tested. The vitamin C content of whole red pepper was higher than that of sliced red pepper or crushed red pepper. Room-temperature thawing resulted in twice the drip loss seen on low temperature($5^{\circ}C$) thawing or microwave oven thawing. Brown discoloration was a serious problem with room temperature thawing. Total free sugars were higher in samples thawed at low temperature or in the microwave oven, compared to the level seen after room-temperature thawing. pepper samples thawed at low temperature scored higher in sensory tests than samples thawed at room temperature.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.5
• /
• pp.674-680
• /
• 2005

The purposes of this study were to compare the effect of several reheating treatments (heating in the frying pan, convection oven and microwave oven) on sensory characteristics and to evaluate the safety during storage period of cook/chill Pajeon. The sensory evaluations were made on 5 sensory attributes by a 9-member panel using quantitative descriptive analysis (QDA). The fresh cooked Pajeon and the Pajeon reheated in the frying pan obtained a significantly (p<0.01) higher score in taste than the ones reheated in a convection oven and microwave oven. The reheated cook/chill Pajeon had a significantly (p<0.01) lower score in flavor than the freshed cooked one. Regardless of the reheating methods, sensory scores in texture of the Pajeon reheated at $v$ for 1 day were not different from that of fresh cooked one. However, the scores of the reheated ones in a convection oven and in a microwave oven decreased with storage time up to 5 days at $3^{\circ}C$. On the other hand, the Pajeon reheated in the frying pan, even after 3 days' storage at $3^{\circ}C$, was not found to be inferior to the freshed cook one in every quality attributes except flavor. Therefore, the reheating treatment in frying pan may be superior to those in a convection oven and a microwave oven. The safety of Pajeon was also evaluated by measuring total count, coliform count, psychrotrophic count, acid value and peroxide value during 5 days of storage periods at $4^{\circ}C$. Total counts of Pajeon was ranged from not detectable to $5.2\times10^2$ CFU/g. The coliform and psychrotroph were not detected at all experiments. The acid values were ranged from 1.90 to 4.03 mg of KOH/g of fat until 5 days at $4^{\circ}C$. And the peroxide values were ranged from 3.63 to 12.50 meq of peroxide/kg of fat until 5 days of storage period. Therefore, these results demonstrated that Pajeon is microbiologically and chemically safe during 5 days of storage period at refligeration temperature.

• Applied Chemistry for Engineering
• /
• v.18 no.4
• /
• pp.344-349
• /
• 2007

NaY zeolites synthesized by microwave heating were compared with those obtained by conventional heating. When the same temperature increasing rates were adopted in both heating methods, the microwave heating shortened the induction period and enhanced the rate of crystallization of NaY zeolites compared with the conventional heating. Irrespective of microwave radiation, the fast temperature increasing rate also shortened the induction time and enhanced the crystallization of NaY zeolites. The crystal sizes of NaY zeolites were large under the fast temperature raise of the reaction mixture and became larger by microwave radiation. At the same time, the fast temperature increasing rate has reduced the energy consumption due to the fast completion of reaction during the synthesis of NaY zeolite. The energy consumption in the conventional ethylene glycol bath was lower than that in the microwave oven with the same temperature increasing rate in this study, which means that the energy efficiency is not always high in microwave heating. If the temperature increasing rate is carefully controlled, however, NaY zeolite can be produced with high energy efficiency in the microwave oven.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.11
• /
• pp.1721-1727
• /
• 1989

Carbon-ferrite microwave absorbers were designed experimentally and fabricated trialy, as a result of which the relative frequency bandwith of 7.3 to 8.2% were obtained under the tolerance limits of the reflection coefficients lower than -20 dB, and the matching thickness becomes 1.4 to 1.6mm, which is significantly thinner than that of the conventional ones. Furthermore, attenuation has been founded by measuring the material constants of the microwave absorbers for microwave oven and the results are compared and discussed.

• Korean journal of food and cookery science
• /
• v.28 no.5
• /
• pp.623-628
• /
• 2012

The study was about to produce red ginsengs easily, using a household microwave oven to promote the consumption of fresh ginsengs in the home. Producing red ginsengs with a household microwave oven 'defrost function' takes 13 minutes (A), 'cook function' 6 minutes (B), and finally, 'defrost function' 44 minutes (C). For characteristics of microwave-produced red ginsengs, total saponin loss, color of powder, polyphenol content and saponin composition were compared with common red ginsengs. The color test for red ginseng powder showed that the color of household microwave-produced 6-minute cooked red ginseng (B) or 44-minute defrosted red ginseng (C) was closer to that of the common red ginsengs (E). The total saponin content in water eluted during red ginseng production showed that the saponin loss in microwave red ginseng was negligible compared to the common red ginsengs. Microwave red ginsengs showed no difference in phenol content that of the and higher total ginsenoside content than common red ginsengs. The ginsenoside $Rg_1$, Re, Rf, $Rg_2+Rh_1$, $Rb_1$, Rc, $Rb_2$, $Rb_3$, Rd and $Rg_3$ contents of microwave red ginsengs (A, B) were higher compared to that of the common red ginsengs; the ginsenoside Re, Rc, $Rb_2$, $Rb_3$, Rd and $Rg_3$ contents of 44-minute defrosted red ginseng (C) were higher compared to the common red ginsengs. It is considered that red ginseng production, using microwave oven at home, can be a fast and convenient way to produce highly functional red ginsengs with high ginsenoside content.

• Journal of the Korea Institute of Building Construction
• /
• v.23 no.2
• /
• pp.143-152
• /
• 2023

In this research, the microwave oven drying method was investigated as a potential accurate testing approach for determining the water content of fresh concrete. To do so, water content estimation formulas employed in three prominent oven drying test methods were selected, and the calculation principles for each equation, along with potential error factors arising during the actual testing process, were considered. Moreover, a concrete test was conducted to validate the possible error factors. Consequently, it was confirmed that estimation errors in the water content of fresh concrete can occur due to sample deviations arising during the wet screening process for creating mortar specimens or deviations in the coarse aggregate sampling quantity during the sample collection process.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.40 no.1
• /
• pp.51-58
• /
• 2020

As interest in lunar exploration increases, studies on lunar surface environment simulation including a lunar soil simulant are being conducted. One of the problems when creating a vacuum environment with lunar soil is that it takes long time to reach high vacuum due to outgas from the soil. Most of the outgas is water, and the time to reach high vacuum can be significantly reduced by a pretreatment process that removes moisture adhering to the surface of the lunar soil before putting soil into a vacuum chamber. The existing soil drying methods were examined to determine how these methods were effective to remove moisture from the lunar simulant soil. Drying experiments of lunar soil samples were carried out using a dry oven, a microwave oven, direct heating method and a vacuum oven, and the results of the drying experiment were presented. Drying soil at 110℃ using a dry oven and drying soil by a microwave oven were not enough to remove moisture, and vacuum oven drying method and direct heating drying method at more than 200℃ were effective in water removal.

• Proceedings of the KIEE Conference
• /
• 1984.07a
• /
• pp.41-43
• /
• 1984