• Title/Summary/Keyword: Microwave oven

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Rapid Moisture Content Determination Technique Using Microwave Oven (마이크로웨이브 오븐을 이용한 금속 함수율 측정법에 관한 연구)

  • Lee, Hyoung-Woo;Kim, Kyung-Yong
    • Journal of the Korean Wood Science and Technology
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    • v.29 no.4
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    • pp.16-24
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    • 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.

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A Design of Driving Circuit for Microwave oven using Phase-shifted FB-ZVS PWM Switching (Phase-shifted FB-ZVS PWM 스위칭을 이용한 Micorwave oven 구동회로 설계)

  • 이완윤;정교범;신판석
    • The Transactions of the Korean Institute of Power Electronics
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    • v.6 no.3
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    • pp.265-272
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    • 2001
  • The traditional 60[Hz] power supply for during magnetron in microwave oven has disadvantages of heavy weight and low efficiency due to 60[Hz] High Voltage Transformer(HVT), capacitor and th phase control of thyristors. To alleviate these disadvantages, this paper proposes a 20[kHz] phase-shifted Full-Bridge(FB) Zero-Voltage-Switched(ZVS) PWM converter for driving a 600[W] magnetron in an 1[kW] microwave oven. The proposed converter has advantages of light weight and high power density.

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A Study on the Measurement of Water Content in Hydrogel Contact Lens by Gravimetric Method (중량측정법에 의한 하이드로젤 콘택트렌즈의 함수율 측정에 관한 연구)

  • Kim, Tae-Hun;Ye, Ki-Hun;Sung, A-Young
    • Journal of Korean Ophthalmic Optics Society
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    • v.13 no.4
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    • pp.59-63
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    • 2008
  • Purpose: The purpose of this study is to understand a relation of water content measurement with two different method, water removal method and dry method. Methods: 72 hydrogel contact lens containing various water content (ranged from 47% to 58%) were measured by the gravimetric method at 20$^{\circ}C$and 21% of the humidity. We weighed the dried test specimen at room temperature for 30 min after cooling. Results: In dry blotting method, the water content was measured to 47.43${\pm}$8.48%. The water contents was measured to 48.15${\pm}$8.36% with wet blotting condition. It was found that wet blotting method showed the higher water content of about 7% than dry blotting method. In water content with two dry methods, each of results was measured by 47.89${\pm}$8.06% and 49.56${\pm}$7.06%. In case of microwave method, the water content was measured significantly higher water content of about 1.67% than vacuum oven method. However, no statistical difference was found (p>0.05). Conclusions: In water removal method (Dry blotting method and Wet blotting method) to weigh hydrated test specimen, wet blotting method showed significantly higher water content than dry blotting method. Also in case of dry methods (vacuum oven and microwave) to weigh dry test specimen, water content of microwave method showed higher water content than vacuum oven method, but it should be noted that microwave oven method must be used carefully to measure accurateness on the specimen position and wave power.

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Rapid Preparation of Soybean Curd Using of Ultra Fine Soy Powder by Microwave Oven (전자렌지를 이용한 초미세 대두분말두부의 신속제조)

  • 김순동;김미경;김미향;이명숙
    • Journal of the East Asian Society of Dietary Life
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    • v.4 no.2
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    • pp.45-49
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    • 1994
  • The rapid preparaton method of soybean curd with ultra fine soy powder at home was investigated. The microwave oven of this study used common microwave attached sensor for the volume and temperature control, The temperature of the microwave oven was maintained at 98, not boiling over. It took 9 minutes to make 300g of soybean curd, 10 minutes to make 600g, 14 minutes to make 900g, and 17 minutes to make 1200g. Beany flavor and trypsin inhibitor could be removed by this conditon. It took only 5 min to make coaguation of the curd by glucono-$\delta$-lactone.

Effects of Ceramic Coating for Microwave Blanching on Vegetables (전자레인지의 Ceramic Coating이 채소류의 마이크로파 데치기에 미치는 영향)

  • Kum, Jun-Seok;Han, Ouk
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.25 no.6
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    • pp.951-957
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    • 1996
  • Changes in quality of blanched vegetables(carrot, green onion, spinach) by microwave heating were evaluated. Ceramic coating treatment(CCT) within microwave oven caused the reduction of blanching time and Hunter's L, a, b values of vegetables. Also, CCT showed the higher cutting force compared to NCCT after microwave heating. Photomicrographs of cross-section of blanched vegetables after heating in ceramic coated microwave oven showed better appearance than those in nonceramic coated microwave oven. CCT process improved retention of vitamin C.

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Interference Effect of Microwave Oven Noise to Wireless LAN Using a GTEM Cell (GTEM Cell을 이용한 전자레인지 잡음이 무선 랜에 미치는 간섭 영향 분석)

  • Chung, Yeon-Choon;Jeon, Sang-Bong;Kwun, Suk-Tai;Yun, Jae-Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.3
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    • pp.240-247
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    • 2009
  • In this paper, we proposed the method of the interference evaluation between the microwave oven noise and the wireless LAN(Local Area Network) by using the GTEM cell. We used microwave oven noise in time to assess the interference unintentional noise effects on wireless LAN and realized by combining an AM(Amplitude Modulation) modulator and a FM(frequency Modulation) modulator. Also the GTEM cell can be used to guarantee the reliability by the evaluations of the frequency and time responses. As measurement results for the APD(Amplitude Probability Distribution) of the interfering noise we analyzed the effect of microwave oven noise to the throughput of wireless LAN.

Series Resonant Full Bridge Inverter for Battery-fed Microwave Oven (배터리 구동 전자레인지를 위한 직렬 공진형 풀브릿지 인버터)

  • 鄭 龍 采;韓 盛 軫
    • The Transactions of the Korean Institute of Power Electronics
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    • v.7 no.2
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    • pp.165-170
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    • 2002
  • In order to solve the problem of system efficiency reduced on account of two stage power conversion, we propose a series resonant full bridge Inverter circuit for battery-fed microwave oven. This circuit has both a compact size and a light weight comparing with the conventional HVT(High Voltage Transformer) method. Also, it may be adjusted power levels of the microwave oven by a frequency control. In this paper, operational principles are explained in detail in order to understand the circuit operation. Also, a proto-type Inverter circuit with 1[kW] Power consumption is built and tested for verifying the operation.

The Universal Design of Microwave Oven considering Old Persons (노인 사용자를 고려한 전자렌지의 유니버셜 디자인)

  • Song, Bok-Hui;Yun, Han-Gyeong;Jeong, Gwang-Tae
    • Journal of the Ergonomics Society of Korea
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    • v.19 no.1
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    • pp.37-48
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    • 2000
  • Universal design is an approach to create environments and products that recognizes the diversity of users, regardless of their ability or age. Recently, old person and disabled person rapidly go on increasing in number. So, universal design concept becomes more and more important in product and environment, etc. In this study, we dealt with the universal design problem of microwave oven considering old persons. New design model for microwave oven was developed and evaluated using human factors approach. The principles of universal design was developed through literature survey and questionnaire survey for old persons, and then design alternatives were developed according to these principles. Two experiments were performed in this study. The purpose of the first experiment was to select final design alternative and the experiment was performed using rapid prototypes. The second one was a usability testing for the real model of final alternative. In this experiment, the real model was compared with the existing real product. As the result, the new design model was a little more excellent than the existing model in usability.

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A Study on the Dropping Shock of Household Electric Appliances during Materials Handling (가전제품의 하역 중 낙하충격에 관한 연구)

  • Lee, Soo-Keun
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.6 no.1
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    • pp.37-40
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    • 2000
  • This study was carried out to investigate dropping shock of household electric appliances during materials handling. Microwave oven($18{\ell}$), TV(16") and washing machine(6.2kg) were singled out as the study items. From the results of dropping test by KS A 1026(General Rules of Performance Testing for Packaged Freights), relative equations were gained as follow : y=0.0863x+10.032 for microwave oven, y=0.136x+7.85 for TV and y=0.214x+5.8 for washing machine (where y is G-factor and x is Dropping height). The maximum values of dropping shock during materials handling were measured to be $11{\sim}14G$ for microwave oven, $12{\sim}15G$ for TV and $10{\sim}12G$ for washing machine. The maximum shocks of microwave oven, TV and washing machine during materials handling were corresponding to dropping shocks of dropping height 45.98cm, 52.57cm and 28.97cm by KS A 1026.

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Shape Optimal Design of the Door Frame of a Microwave Oven to Minimize Its Twisting Deformation (비틀림 변형 최소화를 위한 전자레인지 도어 프레임의 형상 최적설계)

  • Lee Boo-Youn;Koo Jin-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.8 s.251
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    • pp.1016-1023
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    • 2006
  • When one opens the door of a microwave oven during its operation, twisting deformation of the door occurs, which may cause leakage of microwave through the gap between the door and the front plate. A numerical optimization is implemented to minimize the gap by maximizing twisting stiffness of the door of the oven. Design variables are deformed, which describe the shape of the bead in the horizontal and vertical flanges of the door frame. To minimize the twisting deformation, Two optimal design problems to find shapes of the bead in the flange are established. The problems are solved by a numerical optimization technique, their results being evaluated.