• Korean journal of food and cookery science
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• v.26 no.2
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• pp.165-170
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• 2010

Although the demand of ready-to-eat (RTE) foods such as Kimbab is growing, large quantities and wide distribution of these foods is difficult due to their short shelf-life, exposed packaging with hygienic risk, and decreased quality at refrigerator temperatures. This study was undertaken to develop preservation and storage methods to extend the shelf-life of RTE rice products using microwave and packaging methods such as vacuum and modified atmosphere packages. RTE rice ball samples inoculated with Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus or Bacillus cereus were microwave treated for 0, 30, 60, 90 and 120 seconds. Populations of pathogens on the rice balls were significantly reduced with an increase in treatment time. There were more than 5 log reductions of all pathogens when the samples were microwave treated for 60 seconds. RTE rice balls inoculated with two pathogens (S. aureus and B. cereus) were packaged via air, vacuum, $N_2$ gas, and $CO_2$ gas following microwave treatment for 90 seconds. The initial S. aureus and B. cereus concentration before treatment was 7.60 and 6.59 log CFU/g, and these levels were reduced by 3.37 and 2.18 log CFU/g after microwave treatment. The levels of pathogens were significantly increased during storage time at room temperature. $CO_2$ packaging was the most effective at inhibiting microbial growth among the tested packaging methods. The levels of total mesophilic count, S. aureus and B. cereus after 5 days of storage were 7.7, 8.8 and 9.3 log CFU/g in air packaged samples and 2.4, 3.2 and 8.3 log CFU/g in $CO_2$ gas packaged samples, respectively. However, after 3 days of storage higher levels of B. cereus were observed in all samples, indicating that the samples were not safe to be consumed. Base on these results, microwave treatment and MAP packaging methods using $CO_2$ gas could be used as a potential method for extending the shelf-life of RTE foods.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.347.1-347.1
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• 2014

최근, 박막 트랜지스터는 빠른 동작 속도, 낮은 공정비용 그리고 저온공정 등의 특성을 필요로 하고 있다. 그 중 indium-zinc oxide (InZnO)는 높은 전기적 특성, 높은 광 투과도 그리고 우수한 안정성 때문에 기존의 반도체를 대체할 수 있을 것으로 기대된다. InZnO의 경우 indium과 zinc의 조성비에 따라 특성 변화의 차이가 크기 때문에 다양한 조성비에 대한 연구가 보고되고 있는데, 기존의 InZnO 박막을 증착하는 방법의 경우에 조성비의 변화 과정에 많은 공정상의 어려움이 있다. 이 같은 문제점 때문에 조성비의 변화를 용이하게 할 수 있는 용액공정을 이용한 연구가 진행되고 있다. 또한 용액공정은 높은 균일성, 공정 시간 및 비용 감소 그리고 대면적화가 가능한 장점을 가지고 있다. 한편, 용액공정을 기반으로 한 InZnO의 경우에 용액 상태에서 고체 상태의 순수한 금속 산화물 상태로 바꾸기 위해 post-treatment 가 필요하다. 일반적으로 furnace 열처리 방법을 사용하는데, 이 경우 낮은 열효율 및 고비용 등의 문제점을 가지고 있다. 특히 glass 또는 flexible 기판의 경우 열처리 온도에 대한 제약이 있다. 이러한 문제를 해결하기 위한 방법으로 최근에 microwave irradiation를 이용한 저온 post-treatment 방법이 보고되고 있다. Microwave irradiation는 짧은 공정시간 및 열 균일성 등의 장점이 있다. 따라서 본 연구에서는 다양한 indium과 zinc의 조성비를 갖는 용액을 제작한 후 spin coating을 이용하여 증착한 InZnO 기반의 박막 트랜지스터를 제작하였다. Furnace와 microwave 방식으로 post-treatment 하여 비교 평가한 결과 microwave irradiation 한 경우 furnace 열처리 한 경우 보다 더 안정된 동작 전압을 가지는 것으로 나타났다. 따라서 저온공정이 가능한 microwave irradiation 방법으로 post-treatment 한다면 차세대 산화물 반도체로서의 적용이 가능할 것으로 기대된다.

• Food Science of Animal Resources
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• v.28 no.4
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• pp.499-504
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• 2008

Even though pork have frequently induecd allergic reactions in Korea, few papers have been published on pork allergy. This study was carried out to investigate the changes in allergenicity of porcine serum albumin (PSA) by microwave, sonication, and high hydrostatic pressure (HHP). The binding ability of p-IgG to PSA treated with microwave (1,5, or 10 min) directly decreased with increasing treatment time. Particularly, the binding ability of PSA treated 10 min was about 30%. Immunoblotting assay with p-IgG showed that band of PSA treated microwave directly disappeared at 5 and 10 min. However, the binding ability of PSA was not changed by the microwave treatment without heat. Also the reduction of allergenicity by sonication or HHP treatment was not found. In conclusion. allergenicity of PSA treated with microwave directly decreased with increasing time, therefore these results may be used for development of hypoallergenic pork.

• Journal of the Korean Society of Tobacco Science
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• v.28 no.1
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• pp.51-57
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• 2006

This study was carried out to improve and evaluate the analytical method for determination of potassium in tobacco leaf by various pre-treatment techniques. The time requirment of various pre-treatments was about 10 hour for dry ashing and 6 hour for microwave digestion and 3 hour for sonication. The results of recover in both pre-treatment techniques, microwave digestion and sonication, is greater than 85 % stably with reproducibility(RSD %) on replicates of less than 3 %. However the mean values for microwave digestion were lower than certified standard value of NlST SRM. Compared to the other pre-treatment techniques, analytical results for sonication technique strictly improved the accuracy and precision. In conclusion, the use of the simple sonication technique seems to be efficient for the determination of potassium in tobacco leaf in consideration for both the accuracy and reproducibility.

• The Journal of Engineering Research
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• v.4 no.1
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• pp.93-107
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• 2002

The active carbon waste which was used in water purification plant was investigated for the improvement of capillary after microwave treatment. The variation of surface area was measured with the various kinds and amounts of active carbon. The water vapor as the activator was verified to improve the capillary but it reacted with the water contained in waste active carbon. In contrast to the water vapor, the $CO_2$ gas improved the surface area about 10-20 % compared to as received one. The best results was observed at the intensity of 2.75 kw microwave. The more effective recovery of active carbon waste was observed at the microwave treatment compared to the rotary kiln treatment. However, the mass production is so difficult in the microwave process.

• Journal of Soil and Groundwater Environment
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• v.20 no.5
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• pp.11-15
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• 2015

The three processes of 1) high- & low-temperature microwave heatings, 2) the soil washing, and 3) the thermal desorption processes in soil remediation are analysed on the treatment cost data for 2003-2012 years. The cost of microwave heating method with at temperature 500-700℃, for 30 minutes, and at 4-6 kW is approximately 10 $/ton (13,000 ₩) due to the deep through heating of micro-wave, the soil washing with chemicals is about 80 $/ton (85,000 ₩) due to the chemicals & duration, and the thermal desorption process is around 40 $/ton (41,000 ₩) from the less efficiency. Furthermore the sustainability has been assessed, and suggestions are made. 1) Green; the minimal environmental footprint, 2) Growth; the least cost, 3) Shared; the social & environmental justice, 4) Smart; the microwave characteristics of deep through irradiation & heating, and 5) Mutuality; the flexibility of the technology. More additives including water, the government support, and public relation are suggested realizing the microwave in this condition is not harmful to human beings.

• Environmental Engineering Research
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• v.15 no.4
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• pp.225-230
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• 2010

In order to treat soil contaminated with high percentages of water and petroleum, the combined microwave and thermal desorption process was studied, which was composed of the consecutive connection of two pre-treatment processes. For the thickness of the contaminated soil layer on the transfer conveyor belt, the optimal total petroleum hydrocarbon (TPH) removal rate was studied with respect to the duration of microwave exposure in the consecutive process combined with thermal desorption. The TPH removal rate when the contaminated soil layer thickness was 1 cm at 6 kW of microwave power was 80%. The removals rates for 2 and 3 cm soil layer thicknesses were both 70%. Under identical experimental conditions, the TPH removal rate for the microwave pre-treatment, when considering the soil particle size, was over 70%. The lowest TPH removal rate was achieved with a particle diameter of 2.35 mm. For contaminated soil with 30% water content, 6 kW and a thermal desorption temperature of $600^{\circ}C$ were the optimal operational conditions for the removal of THP. However, considering the fuel consumption cost, 4 kW and a thermal desorption temperature of $300^{\circ}C$ would be the most economic conditions.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.612-621
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• 2013

Microwave-assisted extraction (MAE), which is known as less time and less solvent than current extraction methods, was applied to hydrocarbons extraction from irradiated soybean. Among the transported agricultural products, soybean was selected as representative samples for possible application of irradiated treatment and identification of radiation-induced markers. Using 4 kGy-irradiated soybean, different microwave extraction conditions (extraction time and microwave power) were applied and the changes in hydrocarbon concentrations were monitored. The predicted optimum extracted condition for hydrocarbon analysis of soybean was found to be microwave extraction with a microwave power of 97 W and extraction time of 2.2 min. This extraction time was significantly lower compared to the common extraction time of 12-24hr.

• Carbon letters
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• v.17 no.1
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• pp.1-10
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• 2016

Lignocellulosic biomass conversion to biofuels such as ethanol and other value-added bio-products including activated carbons has attracted much attention. The development of an efficient, cost-effective, and eco-friendly pretreatment process is a major challenge in lignocellulosic biomass to biofuel conversion. Although several modern pretreatment technologies have been introduced, few promising technologies have been reported. Microwave irradiation or microwave-assisted methods (physical and chemical) for pretreatment (disintegration) of biomass have been gaining popularity over the last few years owing to their high heating efficiency, lower energy requirements, and easy operation. Acid and alkali pretreatments assisted by microwave heating meanwhile have been widely used for different types of lignocellulosic biomass conversion. Additional advantages of microwave-based pretreatments include faster treatment time, selective processing, instantaneous control, and acceleration of the reaction rate. The present review provides insights into the current research and advantages of using microwave-assisted pretreatment technologies for the conversion of lignocellulosic biomass to fermentable sugars in the process of cellulosic ethanol production.

• Journal of environmental and Sanitary engineering
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• v.11 no.2
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• pp.65-73
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• 1996

The objective of this study is to investigate the removal efficiency of volitile organic compounds in soil, and the mechanism of desorption by bench scale microwave heating, Silt soil used for experiment and was impregnated with toluene, tetrachloroethylene, o-xylene and p-dichlorobenzene and the microwave treatment was conducted in a modified domestic microwave oven : 2450MHz, 700W. According to the results of the research the removal efficiency was improved with increasing water contents and the soil temperature appeared to plateau period extending to 2-3minutes corresponds to the temperature a which steam distillation was expected. The value of removal rate constant (k) were calculated on dry and moisty silt soil, respectively, which showed linear with increasing microwave heating time. Therefore, addition of a certain amount of water to the contaminated soil can efficiently enhance the ability of the soil to absorb microwave energy and promote the evaporation of the volitile contaminants.