• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.2174-2176
• /
• 2000

FDTD(Finite Difference Time Domain) 방법을 적용하여 마이크로웨이브 오븐 내부의 전자기장을 해석하였고, 적외선사진을 통하여 실험과 비교 검증하였다. 부하의 종류와 형태에 따른 전자기장의 패턴 변화를 고찰하였고, 여러 가지 포밍형태와 오프닝 형태에 따른 전자기장의 패턴을 적외선 사진과 비교하였다. 표면 보정 기법을 적용하여 부하표면에서의 전자파 패턴을 보다 정확히 예측할 수 있었으며, 또한 마그네트론의 공진 주파수에 따른 전자파 파워 패턴의 변화를 살펴 보았다. 이와 같이 개발된 마이크로 웨이브 오븐 내부의 전자파 해석 프로그램을 이용하면, 균일 가열 성능 향상을 위한 마이크로웨이브 오븐의 캐비티 설계 기간을 크게 단축할 수 있을 것으로 생각된다.

• Journal of the Korean earth science society
• /
• v.38 no.2
• /
• pp.150-160
• /
• 2017

In order to determine the porosity of rock, the 'standard test method for porosity and density of rock' proposed by the Korean Society for Rock Mechanics is commonly used. However, the standard test method, which uses a drying oven, takes 8 to 24 hours to complete the test in taking samples out of the oven every four hours and measuring the weight of the specimen. To complement these disadvantages, we devised a method for measuring rock porosity by using a microwave oven. The devised method reduced the cause of errors and the inconvenience occurred in the process of weighing samples by constructing a weight monitoring system, which monitors the drying process. A suitable heating/pause time was set up to maintain the temperature of sample below $105{\pm}3^{\circ}C$ in drying process, and an alarm system was implemented in order to stop drying process when the weight change of the rock sample is within 0.1% of the initial weight. The porosity was determined from the dry weight of the sample, which was obtained by the curve fitting of weight monitoring data. Then, the porosities obtained by using the microwave oven were compared with those obtained by the standard test method. Test results using sandstone samples showed that the porosities obtained by a microwave oven was similar to those obtained by the standard method and the porosity difference between two methods was as large as 0.4%. In addition, repeated porosity measurement using the same specimen showed that the standard deviation of the porosity, which reflects the precision of the measurement was as good as 0.23%. Therefore, a microwave oven porosity measurement system can give the porosity of rock samples with high reliability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.10a
• /
• pp.214-217
• /
• 2001

Microwave continuous drier system mostly uses the ISM frequency band(915MHz or 2450MHz). It dry the material off from it's inside by the electromagnetic wave. The structure whose openings is needed for dry system to continuously feeds a materials into the system. So it is too difficult to shield the leakage of electromagnetic energy through the apertures. In this paper, we designed microwave continuous drier structure which operates at 2450MHz and analyzed the field distributions at the internal and external region of the structure.

• Proceedings of the KIEE Conference
• /
• 1999.07e
• /
• pp.2459-2461
• /
• 1999

FDTD(Finite-Difference Time-Domain) 방법을 이용하여 마이크로웨이브 오븐 내부 전자파를 해석하였고, 열전달방정식을 이용하여 부하의 열 분포를 해석하였다. 다양한 형태의 오프닝구조를 갖는 캐비티에 관하여 수치계산을 수행하였고, 서로 다른 종류의 부하가 존재할 때 부하의 온도 분포가 어떻게 변화하는지 알아보았다. 또한 마그네트론의 안테나와 캡이 존재하는 실제 웨이브가이드를 모델링하여 수치 계산한 후, 적외선사진에 의한 부하의 온도분포와 비교하였다.

• 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.

• Journal of the Korean Wood Science and Technology
• /
• v.29 no.4
• /
• pp.16-24
• /
• 2001

Conventional hot-air oven-drying method takes at least four hours to determine the moisture content of wood sample and this method is not always acceptable to wood industry. In this study samples of six different specifications from Paulownia coreana, Pinus densiflora and Quercus acutissima were dried in domestic microwave oven to their oven dry weights to investigate the possibility of rapid moisture content determination technique using microwave-oven drying method. Continuous heating time, cooling time and intermittent heating time were determined by each species and sample specifications. Temperatures of surface and center of samples were also measured during drying. Oven-drying times were reduced to 1/7~1/10 of conventional hot-air oven-drying method. Therefore microwave heating and drying techniques appear attractive for wood industry as a rapid moisture content determination method.

• Environmental engineer
• /
• s.65
• /
• pp.18-24
• /
• 1992

우리나라와 같이 전기제품의 수출이 전체수출의 많은 부분을 차지하는 상태에서는 전자파장해의 정확한 측정기술의 개발, 전자파대책 부품과 기술개발 등의 연구가 요구되고 있다. 특히 레이저, 마이크로 웨이브 오븐, 고광도 광원 등과 같은 방사선을 이용하거나 발산하는 전자 창작품의 생산이 급격한 성장을 보이고 있는 가운데 비전리 방사선에 의한 공중건강에 관심이 높아지고 있다.

• Journal of the Korean Chemical Society
• /
• v.47 no.6
• /
• pp.591-596
• /
• 2003

Aminothienopyridazines 1a, b and aminothienocoumarin 2 condensed with DMFDMA to yield amidines 3a, b and 4. These compounds reacted with N-phenylmaleimide to yield 9 and 10. On the other hand reacting 3a, b, 4, 18, 19 and 20 with maleic anhydride afforded only the formylated derivatives 5a, b, 6, 21, 22 and 23 respectively. The reaction of 3a, b with diethyl fumarate afforded 11, formed most likely via hydrolysis of the amidine 14 during working up the reaction mixture. Irradiation of N-phenylmaleimide in microwave oven afforded [2+2] and [2+2+2] cycloaddition product.

• Journal of Applied Tourism Food and Beverage Management and Research
• /
• v.15 no.1
• /
• pp.113-125
• /
• 2004

Effect of microwave radiation on physico-chemical properties of cor'n starches was studied. Waxy com, com and high amylose com starches of varying moisture content(20～35%) were subjected to microwave processing(2450MHz) at $120^{\circ}$ and the experimental starch samples were examined by a X-ray diffractometry, rapid viscosity analyzer(RVA) and. with the samples in temperature was observed and the peaks of high amylose com starches at $2^{\circ}$=5.0, 15.0 and $23.0^{\circ}$, were disappeared indicating the melting of crystallines while those of com and waxy com had not changed. A change in gelatinization pattern was observed in the case of corn starches from type A with nearly no peak-viscosity and breakdown to type C. Except a decreased viscosity, no change was observed in those of waxy com starches.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.22 no.4
• /
• pp.100-106
• /
• 2008

Typical household load have nonlinear loads including a personal computer, video, refrigerator, microwave oven, TV, and audio set. These nonlinear loads generate harmonic currents and create distortions on the sinusoidal voltage of the power system. Harmonic field measurements have shown that the harmonic contents of a waveform varies with time. A cumulative probablistic approach is the most commonly used method to solve time varying harmonics. This paper provides in depth analysis on harmonics field measurement of the typical household loads and harmonics simulation using EDSA program for the case study.