• Current Research on Agriculture and Life Sciences
• /
• 제32권1호
• /
• pp.1-9
• /
• 2014

본 연구에서 사용한 QRD(Quadratic Residue Diffusor) 마이크로파는 일반적인 마이크로파와 달리 파장의 위상차를 변화시켜 균일한 살균을 유도할 수 있어 저전력으로 효과를 높일수 있는 새로운 기술로 알려져 있다. 따라서 친환경적이고 에너지 소비가 적은 QRD 마이크로파를 이용하여 목재를 소독 할 가능성에 대한 기초적인 연구를 수행하였으며 얻은 결과는 아래와 같다. 본 연구에 사용된 QRD microwave의 효율성은 E=5.75e0.32S ($R^2$=0.908)로 나타났으며 초기 수분 함수율은 일정하지 않았고 평균 수분함수율은 30.3%이었다. 자연건조 1주일 후의 수분 함수율은 22.6%로써 평균 약 8% 수분함량이 줄어들었다. 또한 마그네트론의 용량이 3 kW에서 9 kW까지 증가할수록 지수함수적인 관계로 온도 상승시간이 줄어드는 것을 알 수 있었다. 목재 강도 시험 결과에서는 QRD microwave 처리 전후로 휨강도, 압축강도, 할렬의 차이는 없었다. 따라서 QRD microwave 용량을 3, 5, 7, 9 kW로 제작하여 실험한 결과 9 kW가 가장 효율성이 높은 것을 알 수 있었다. 따라서 목재 내부의 선충이나 흰개미 등의 퇴치를 위해서 QRD microwave 용량을 일정부분까지 높여 공급할수록 에너지 효율성에서 유리한 것으로 나타났다.

• Elastomers and Composites
• /
• 제32권5호
• /
• pp.318-324
• /
• 1997

Since the rigid and continuous networks of high-purity silica(white carbon) were relatively transparent to microwaves, high purity silica coupled with microwaves using a zirconia susceptor at room temperature and it was then heated to its melting temperature. The low-purity silica, contained small amount of impurities, yielded greater microwave absorption owing to easy motion of the interstitial alkali ions and it was then heated to its melting temperature. X-ray diffraction patterns of the low-purity silica were broader than those of the high-purity silica due to higher concentration of non-bridging bond and more deformed random network structure. In the vulcanization process of whitened or coloured rubber compound which is employing low-purity silica(white carbon) as a reinforcing filler, vulcanizate could be obtained effectively by microwave heating energy.

• 대한화학회지
• /
• 제54권1호
• /
• pp.55-58
• /
• 2010

포화 그리고 방향족 니트로화합물은 monomode reactor로 CeY zeolite와 formic acid를 사용하여 반응시키면 아민 치환체를 좋은 수율로 선택적으로 환원된다. 이 반응은 몇개의 민감한 작용기를 가진 화합물에 적합하다. 회수한 촉매를 20회 이상 사용 후에도 촉매의 활성을 계속 유지하였다.

• 한국식품조리과학회지
• /
• 제10권4호
• /
• pp.351-356
• /
• 1994

Comparisions were made for cooking times, internal temperatures, thiamin contents and textural properties of various portion weights of egg mixture cooked in a microwave oven at high and/or low power levels and in a conventional double boiler. The mean internal temperatures of conventionally cooked egg mixtures were 76.4~80.7$^{\circ}C$. When cooking was made by steaming, the mean internal temperature were comparable among samples. With the microwave cooking, the range of mean temperature was 83.8~96.4$^{\circ}C$, and they were significantly higher than the conventionally cooked egg mixtures. The hardness determination was conducted using universal testing machine and a taste panel. Samples cooked with steam or with larger portion weight had softer texture than samples cooked by microwaves or smaller amount, respectively. Mean internal temperature was significantly(r=0.99, p<0.05) correlated with mechanical hardness determination. Statistical analyses indicated no significant difference in the thiamin content among various treatments.

• 한국정보통신학회논문지
• /
• 제4권2호
• /
• pp.479-485
• /
• 2000

In this study, the chamber size was designed and manufactured so as to make a resonance with microwaves in sterilizing moisture-contained food by making good use of microwaves. When the green-pea jelly which was made and sterilized for experimental usage with no addition of an antiseptic was left in the room temperature for 1 minute, 2 minutes or 3 minutes respectively, resulted in delaying more greatly the procession of change in quality of food for almost 7 to 15 days than in unsterilized food. As a result of experiment conducted above, it is considered to produce good results of decreasing the resource waste and environmental pollution, by lengthening the period of preservation and circulation of food.

• 한국식품영양학회지
• /
• 제8권2호
• /
• pp.79-87
• /
• 1995

It is generally known that the protein of talk has allergenicity and the allerenicity Induces allergic diseases. Finding methods to reduce the allergenicity of the food and develop methods to make low allergic food is the purpose of this study. For this study, 1 tried various experimental methods : heat treatment, irradation with ultraviolet and microwaves treatment with polyphosphate, enzyme hydrolysis and PCA inhibition test using guinea pigs and degrees of hydrolysis. The results obtained are as follows. Heat treatment reduced allergenicity of milk protein. The higher the heat, the better the effect. Irradiating with ultraviolet and microwave increased both the degree of protein hydrolysis and PCA inhibition reduced the allergenicity. Ultraviolet was more effective than microwaves on milk protein. Enzyme treatment increased the degree of hydrolysis and PCA inhibition, and reduced allergenicity considerably. Neutrase was more effective than alcalase on milk protein. Adding Polyphosphate did not induced protein hydrolysis, but increased PCA inhibition and reduced allergenicity.

• Carbon letters
• /
• 제15권1호
• /
• pp.15-24
• /
• 2014

As a part of the electromagnetic spectrum, microwaves heat materials fast and efficiently via direct energy transfer, while conventional heating methods rely on conduction and convection. To date, the use of microwave heating in the research of carbon-based materials has been mainly limited to liquid solutions. However, more rapid and efficient heating is possible in electron-rich solid materials, because the target materials absorb the energy of microwaves effectively and exclusively. Carbon-based solid materials are suitable for microwave-heating due to the delocalized pi electrons from sp2-hybridized carbon networks. In this perspective review, research on the microwave heating of carbon-based solid materials is extensively investigated. This review includes basic theories of microwave heating, and applications in carbon nanotubes, graphite and other carbon-based materials. Finally, priority issues are discussed for the advanced use of microwave heating, which have been poorly understood so far: heating mechanism, temperature control, and penetration depth.

• Advances in environmental research
• /
• 제1권3호
• /
• pp.191-199
• /
• 2012

A kinetic study of the transesterification of soybean oil was conducted using microwaves under various temperatures, power densities, and reaction times. Results show that power density affects the kinetics and yield. The biodiesel yield increased with increasing microwave power density. The non-thermal effects of microwave irradiation on transesterification reactions were evaluated at a constant reaction temperature ($65^{\circ}C$) and power density (0.204 $Wg^{-1}$). Microwave irradiation was found to increase the reaction rates by 3.52-7.06 fold.

• Computers and Concrete
• /
• 제8권4호
• /
• pp.425-443
• /
• 2011

Most previous studies have generally overlooked the contribution of thermal stresses generated within the concrete mass when subjected to microwave heating and reported on pore-pressure as being the dominant cause of surface spalling. Also, the variation in electromagnetic properties of concrete and its effects on the microwave heating process have not been studied in detail. In this paper, finite element modeling is used to examine the simultaneous development of compressive thermal stresses and pore-pressure arising from the microwave heating of concrete. A modified Lambert's Law formulation is proposed to estimate the microwave power dissipation in the concrete mass. Moreover, the effects of frequency and concrete water content on the concrete heating rate and pattern are investigated. Results show high compressive stresses being generated especially in concrete with a high water content when heated by microwaves of higher frequencies. The results also reveal that the water content of concrete plays a crucial role in the microwave heating process.

• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 2003년도 High Temperature Superconductivity Vol.XIII
• /
• pp.29-29
• /
• 2003