• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2035-2037
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• 1999

This paper describes an ASM(All Solid-state Modulator) pulsed power generator for non-thermal plasma applications. The proposed generator can produce 20kV, 500A, 100ns pulses at repetition rates up to 10kHz, and it is composed of 30 series connections of power circuit card assembly which contains paralleled MOSFETs, MOSFET drivers, energy storage capacitors and specially designed 1:1 pulse transformer. Higher pulse voltages and currents can easily be obtained by increasing the numbers of series and parallel connections of power circuit card and MOSFETs, respectively. Component layouts are optimized to minimize the leakage inductance and the voltage spikes across switching devices. Especially it put emphasis on the over-current protection (including short circuit) for the reliable operation in real situations. Experimental results show that the proposed pulser is very efficient in air pollution control application and could be useful for other applications such as synthesis of nanosize powders and non-thermal food processing.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.5
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• pp.2156-2170
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• 2020

This paper presents a fire detection algorithm with a minimal false detection rate, intended for a thermal imaging surveillance environment, whose properties vary depending on temporal conditions of day or night and environmental changes. This algorithm was designed to minimize the false detection alarm rate while ensuring a high detection rate, as required in fire detection applications. It was necessary to reduce false fire detections due to non-flame elements occurring when existing fixed threshold-based fire detection methods were applied. To this end, adaptive flame thresholds that varied depending on the characteristics of input images, as well as the center of gravity of the heat-source and hot-source regions, were analyzed in an attempt to minimize such non-flame elements in the phase of selecting flame candidate blocks. Also, to remove any false detection elements caused by camera shaking, one of the most frequently raised issues at outdoor sites, preliminary decision thresholds were adaptively set to the motion pixel ratio of input images to maximize the accuracy of the preliminary decision. Finally, in addition to the preliminary decision results, the texture correlation and intensity of the flame candidate blocks were averaged for a specific period of time and tested for their conformity with the fire decision conditions before making the final decision. To verify the fire detection performance of the proposed algorithm, a total of ten test videos were subjected to computer simulation. As a result, the fire detection accuracy of the proposed algorithm was determined to be 94.24%, with minimum false detection, demonstrating its improved performance and practicality compared to previous fixed threshold-based algorithms.

• Food Science and Industry
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• v.43 no.1
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• pp.2-20
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• 2010

• Journal of the Korean Chemical Society
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• v.57 no.1
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• pp.109-114
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• 2013

The effects of aluminum nanoparticles (AlNs) on the thermal decomposition of ammonia perchlorate (AP) were investigated by DSC, TG-DSC and DSC-TG-MS-FTIR. Addition of AlNs resulted in an increase in the temperature of the first exothermic peak of AP and a decrease in the second. The processing of non-isothermal data at various heating rates with and without AlNs was performed using Netzsch Thermokinetics. The dependence of the activation energy calculated by Friedman's isoconversional method on the conversion degree indicated the decomposition process can be divided into three steps. They were C1/D1/D1 for neat AP, determined by Multivariate Non-linear Regression, and changed to C1/D1/F2 after addition of AlNs into AP. The isothermal curves showed that the thermal stability of AP in the low temperature stage was improved in the presence of AlNs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.169-172
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• 2004

The effect of the process parameters on the stable lifetime in rapid thermal firing(RTF) was investigated in order to optimize the process for the Cz-silicon. The process temperature was varied between $700^{\circ}C\;and\;950^{\circ}C$ while the process time was chosen 1 s and 10 s. At below $850^{\circ}C$ the stable lifetime for 10 s is higher than that for 1 s and increases with increasing by the process temperature. However, at over $850^{\circ}C$ the improved stable lifetime is not dependent on the process time and temperature. On the other hand, two high temperature processes in solar cell fabrics are combined with the optimized process and the non-optimized process. The last process determines the stable lifetime. Also, the degraded stable lifetime could be increased by processing in optimized process. The decreased lifetime can increase using the optimized oxidation process, which is a final process in solar cells. Finally, the optimized and non-optimized processes are applied solar cells.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.934-938
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• 1995

Water soluble fractions (WSF) of wheat bran treated with thermal processes such as autoclaving, microwaving and extrusion were characterized to investigate the structural response of plant cell wall to thermal and mechanical energy. From the chemical analysis and gel filtration chromatography of WSF, gelatinization of starch was found to be the primary solubilizing mechanism of wheat bran, followed by the structural disintegration of fibrous non-starch cell wall materials. It was also found that extrusion process resulted in degrading relatively higher molecular weight non-starch polysaccharides from the cell wall. GC analysis of water soluble non-starch polysaccharides indicates that the arabinoxylan residues of cell wall are the most susceptible site to thermal treatments studied. In particular, the degrading degree of cell wall of wheat bran is the most significant for extrusion accompanying both high temperature and high shear.

• Journal of Dairy Science and Biotechnology
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• v.32 no.1
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• pp.31-36
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• 2014

Thermal pasteurization has been effectively used for decades as a method to extend the shelf life of milk and to inactivate any pathogenic bacteria that it may contain; however, it can negatively affect the nutritional properties of milk. In recent years, the food industry has sought new, less aggressive technologies that affect food freshness and its nutritive and health benefits less significantly. Various means have been used to extend the shelf life of dairy foods, such as high-pressure processing, irradiation, ohmic heating, and pulsed electric field (PEF) technologies. Of these, PEF technologies are potential alternatives to traditional thermal milk pasteurization, owing to their advantages in minimizing sensory and nutritional damage. In this review, we have primarily focused on the feasibility of applying PEF technologies to the sterilization of dairy products and briefly discussed whether they should be adopted for use in the dairy beverage industry in the future.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.69-70
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• 2003

최근 실내공기 질(IAQ : Indoor Air Quality)에 관한 인식이 높아지고 있으며 환경개선에 상응하는 기술 개발의 중요성이 크게 부각되고 있다. 실제 산업체에서는 여러 가스정화기술들이 오염물질제거에 이용되어 왔고, 그 한 분야인 N.T.P(Non-thermal plasma Process) 공정도 다양한 각도에서 연구가 수행되어 왔다. 그러나, 이 기술의 실용화를 위한 설계변수 개념의 연구는 부족한 실정으로, 이에 본 연구는N.T.P 공정에 의한 가스정화의 반 경험식 도출과 이를 이용한 성능 평가 고찰이 주목적이다. 또한, 반응기 통과 후 나오는 부산물을 동정하여, 차후 후단에 사용할 촉매를 결정 하고자 한다. (중략)

• Journal of the Korean Society of Combustion
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• v.16 no.3
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• pp.21-26
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• 2011

Thermal analyses are conducted to measure chemical kinetic parameters of an unknown liquid fuel with various components. Thermal Analyses are divided into two different methods such as TGA(Thermo-Gravimetric Analysis) and DSC(Differential Scanning Calorimety). Non-isothermal experimental results are analyzed by adopting TGA and they are filtered by Freeman-Carroll method. As a results of the analysis, chemical parameters of the activation temperature and the reaction order are measured to be 6128.2 K and 1.4, respectively. Furthermore, the chemical kinetic parameters are obtained by a variety of mathematical processing methods. It has been found that they show a little difference depending on the processing method.

• Journal of the Korean Ceramic Society
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• v.54 no.2
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• pp.75-85
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• 2017

Thermoelectric is a key technology for energy harvesting and solid-state cooling by direct thermal-to-electric energy conversion (or vice versa); however, the relatively low efficiency has limited thermoelectric systems to niche applications such as space power generation and small-scale or high-density cooling. To expand into larger scale power generation and cooling applications such as ATEG (automotive thermoelectric generators) and HVAC (heating, ventilation, and air conditioning), high-performance bulk thermoelectric materials and their low-cost processing are essential prerequisites. Recently, the performance of commercial thermoelectric materials including $Bi_2Te_3$-, PbTe-, skutterudite-, and half-Heusler-based compounds has been significantly improved through non-equilibrium processing technologies for defect engineering. This review summarizes material design approaches for the formation of multi-dimensional and multi-scale defect structures that can be used to manipulate both the electronic and thermal transport properties, and our recent progress in the synthesis of conventional thermoelectric materials with defect structures is described.