• New & Renewable Energy
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• v.20 no.1
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• pp.126-134
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• 2024

Biogas, composed mainly of methane (CH₄) and carbon dioxide (CO₂), is a renewable gas that can serve as an alternative energy source. In this study, we developed a new microwave reformer and analyzed its reforming characteristics. We observed that higher temperatures of the microwave receptor led to increased reforming efficiency. By supplying appropriate amounts of methane and steam, we could prevent carbon generated from the thermal decomposition reaction of carbon dioxide from depositing on the catalytic active layer, thus avoiding the inhibition of catalytic activity. Hydrogen generation was enhanced when maintaining the biogas ratio and steam supply at adequate levels. Increasing the SiC ratio in the receptor improved the uniformity of temperature distribution and growth rate, resulting in higher conversion rates of the reforming process.

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

• Journal of Korean Society of Environmental Engineers
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• v.39 no.1
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• pp.34-39
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• 2017

The recent gradual increase in the energy demand is mostly met by fossil fuel, but the research on and development of new alternative energy sources is drawing much attention due to the limited fossil fuel supply and the greenhouse gas problem. This paper assesses the feasibility of producing fuel energy from a dewatered sewage sludge by microwave-induced pyrolysis with sludge char and graphite receptor. Both receptors produced gas, char, and tar in order from product amount. The gas produced for the sludge char receptor contained mainly hydrogen and methane with a small amount of light hydrocarbons. The graphite receptor generated higher gravimetric tar and generated higher light tar. Through the results, the product gas from the microwave processes of wet sewage sludge might be possible as a fuel energy. But the product gas has to be removed the condensable PAH tars.

• Resources Recycling
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• v.19 no.1
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• pp.21-26
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• 2010

In order to understand the microwave carbothermic reduction of steelmaking slag to recover Fe, the effects of gas atmosphere and carbon addition on the carbothermic reduction behavior of CaO-$SiO_2$-FeO slag were investigated. It was found that the maximum temperature and the reduction rate were higher in air than in nitrogen atmosphere. In addition, under air atmosphere, the maximum temperature and the reduction rate were increased by increasing the amount of additive carbon. When the carbon equivalent is 5, the maximum temperature reached as high as 1800K and the reduction rate was approximately 90%. As the Carbon equivalent increased further, the maximum temperature and the reduction rate did not change.

• Journal of the Korean Chemical Society
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• v.56 no.4
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• pp.468-472
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• 2012

Efficient one-pot microwave-assisted synthesis of various benzo-[1,4]-oxazinones via Smiles rearrangement is described. Treatment of 2-chloroacetamide, substituted 2-chlorophenols and cesium carbonate in MeO-PEG-OMe (2,000) as solvent afforded the corresponding benzo-[1,4]-oxazinones and 1H-pyrido[2,3-b][1,4]-oxazin-2-(3H)-one as moderate yield.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.1
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• pp.51-58
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• 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 Applied Tourism Food and Beverage Management and Research
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• v.15 no.1
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• pp.113-125
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• 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.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.05a
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• pp.29-33
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• 2003

최근 이동 정보통신 분야의 발전에 따라 단말기 및 관련 부품들을 소형 경량화 하는 것이 매우 중요한 기술요소로 부각되고 있다. 이를 위해서는 기판의 배선밀도를 높이는 것과 개별 부품 또는 모듈의 크기와 무게를 줄이는 것이 절실히 필요하며, 이러한 요구에 부응하기 위해 기존의 다층 PCB 기술이나 MCM 기술에 비해 우수한 배선밀도와 양호한 전기적 특성을 갖는 저온 동시소성 세라믹(Low Temperature Co-fired Ceramic) 기술이 개발, 적용되고 있다. 본 논문에서는 이러한 LTCC 기판의 소결에 있어 기존의 소결 공정인 전기로 소결 공정과 microwave를 이용한 소결 공정을 이용하여 소결 하였을 때, LTCC 기판의 수축율과 무게감소, 그에 따른 밀도변화, SEM 을 이용한 표면형상 분석을 통해 급속가열을 통한 공정시간의 단축, 낮은 에너지 소비로 인한 제조단가의 절감, 균일한 가열로 인한 소결온도의 저하 등의 장점을 갖는 microwave sintering 을 적용할 수 있는 가능성을 제시하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.1
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• pp.35-42
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• 2019

Recently, the gradual increase in energy acceptance is mostly satisfied by fossil fuels, but research and development of renewable energy sources are attracting attention due to fossil fuel supply and greenhouse gas problem. The disadvantage is that renewable energy can not be produced continuously. This being so, energy storage is an important technology in renewable energy. In this study, microwave was used to convert carbon receptor-carbon dioxide to gas fuel.

• Journal of the Korean GEO-environmental Society
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• v.13 no.10
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• pp.43-53
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• 2012

This study deals with the conventional consolidation methods like preloading and vertical drains. For it, Two different mechanism, i.e., increasing of permeability and evaporating of pore water were studied. The marine clays excavated in Incheon were heated at low temperature($90^{\circ}C$) to increase the permeability. Also, Microwave oven and high-temperature electric heater were used for pore water evaporation. Several points raised from the experiments. To fix them, the electric heating system was revised to upgrade the field application and drain efficiency of pore water, and the marine clays were heated by revised electric heater at high temperature($250^{\circ}C$). From Experimental result showed that results, high-temperature heater induced the pore water evaporation and displayed the excellent consolidation behavior. In addition, the cone index of heated clays were increased about 19 times, which suggested that electric heating system could be applied for ensuring the trafficability of heavy equipments.