• 조명전기설비학회논문지
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• 제26권3호
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• pp.24-30
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• 2012

A proposed the electrical fan heater using induction heating is innovative system which applied IH(Induction Heating) magnetic induction heating generated from induction-heated metallic package and high-frequency power circuit technique for thermal converse technique. In this occurs not burning, so that the working environment and deterioration of products can be improved. The existing heater that low efficiency by heated resistance or using fossil fuel of coal, diesel, kerosene has problems about burden for high cost price. In this paper are compared efficiency the existing heaters and designed electrical fan heaters using 3[kW]-Class full-bridge resonant inverter. In addition, action analysis and application of system are discussed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.157-160
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• 2004

If concrete structure is exposed to high temperature such as long-term fire, damages affecting partial or whole structure system may occur. Therefore accurate diagnosis of deterioration is needed based on mechanism of fire deterioration in general concrete structures. Fundamental information and data on the properties of concrete exposed to high temperature are necessary. Especially, the amount of fire damage done to concrete depends on the materials, the standard design compressive strength of concrete, and heated temperature. So, the object of this study is to present data for supposed heated Temperature of deteriorated concrete by fire.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.239-240
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• 2021

In this study, we conducted a study to evaluate the more accurate mechanical properties of concrete damaged by fire. In relation to this, in this study, the results of compressive strength and biaxial flexural strength were compared for concrete that received high temperature heat. As a result, both the compressive strength and the biaxial bending strength decreased as the heating temperature increased. As a result of examining the correlation between the compressive strength and the biaxial flexural strength, the biaxial flexural strength was smaller than the compressive strength.

• 조명전기설비학회논문지
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• 제24권1호
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• pp.117-123
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• 2010

제안한 유도가열 시스템은 증류탑 장치에 사용되는 특수적층 규칙충진체에 의한 열 교환기술과 IH(Induction-Heating)전자유도가열용의 특수한 고주파 전력회로 기술을 응용한 차세대 가열방식이다. 본 전자유도 유체가열기술은 IGBT대응의 고주파 인버터를 사용하여 상용교류로부터 수[kHz]의 고주파 교류를 발생시킬 수 있다. 공진형 고주파 인버터를 사용함으로 고성능, 고효율의 시스템화가 가능하다. 본 논문에서는 주파수 범위가 20[kHz]에서 44[kHz]인 고주파 공진형 인버터을 이용하여 증기를 발생시키는 유도가열시스템에 대해 제안한 온도제어에 대하여 기술하고자 한다.

• Journal of Power Electronics
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• 제4권3호
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• pp.138-151
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• 2004

In this paper, a constant frequency phase shifting PWM-controlled voltage source full bridge-type series load resonant high-frequency inverter using the $4^{th}$ generation IGBT power modules is presented for innovative consumer electromagnetic induction heating applications, such as a hot water producer, steamer and super heated steamer. The bridge arm side link passive capacitive snubbers in parallel with each power semiconductor device and AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is evaluated and discussed on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency inverter topology, what is called, DE class type, including the variable-power variable-frequency regulation function can expand zero voltage soft switching commutation area even under low output power setting ranges, which is more suitable and acceptable for newly developed induction heated dual pack fluid heaters. Furthermore, even the lower output power regulation mode of this high-frequency load resonant tank inverter circuit is verified so that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.

• 동아시아식생활학회지
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• 제17권1호
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• pp.72-80
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• 2007

The pine mushroom is recognized as a valuable functional food and is considered the first kind of mushroom. One of the product development plans for the pine mushroom is a Teriyaki pickle. The physical properties and sensory evaluation of this product were measured, as well as sensory evaluations and microbe tests after a storage period. 9 types of high pressure-cooking conditions with Teriyaki seasoning were tested. The Teriyaki seasoning was heated from $110^{\circ}C$ for 2 hours, 1 hour or by the traditional method. Based on our testing and evaluations, the pine mushroom Teriyaki pickle heated from $110^{\circ}C$ for 2 hours or 1 hour had the highest preference and color ; Odor and overall preference increased with longer storage periods. Also, from the 21st day, the microbe levels in the traditional method Teriyaki seasoning measured less than those in 30 others. But, until storage 28th day, no microbes were detected in Teriyaki seasoning liquid from the high pressure-cooking condition. As a result, the high pressure-cooking condition was a simpler manufacturing process than the traditional method. The salinity of Teriyaki seasoning liquid from the high pressure-cooking condition was relatively lower than that from the traditional method. Therefore, the pine mushroom pickle prepared with Teriyaki seasoning under high pressure-cooking conditions will be considered for commercialization. The pine mushroom Teriyaki pickle heated from $110^{\circ}C$ for 2 hours was preferred the most, so this method is suitable for the Teriyaki seasoning.

• Journal of Ginseng Research
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• 제32권2호
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• pp.120-126
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• 2008

This study was carried out to investigate the some physicochemical properties of Korean red ginseng (Panax ginseng C.A. Meyer) water extract (RGWE) after heated with high temperatures above $100^{\circ}C$ for 2 hours. RGWEs were heated at 100, 110 and $120^{\circ}C$ for 2 hours by using autoclave. After RGWEs were heated at high temperature for 2 hours without not adjustment of pH, the changes of saponin, free sugars, mineral and color in the RGWEs were investigated. Total ginsenoside content in control was 1.99%, while those of RGWE were 1.65, 1.49 and 1.29% when treated at 100, 110 and $120^{\circ}C$, respectively. The contents of total ginsenoside showed decreased tendency as heating temperatures were increased. The ginsenoside-$Rh_{2}$ and $-Rg_{3}$, which have been reported as very stable red ginseng ginsenosides, showed relatively strong spots on TLC when RGWEs were heated at 110 and $120^{\circ}C$. In case of free sugars in RGWEs, fructose, glucose and maltose showed high contents when compared with control, while Fe, Ca and Mg ions showed very low contents. Value of L in RGWE treated with high temperature was almost the same with control, while values of a and b were increased. Values of a were increased from -0.86 of control to +0.04, +0.05 and +1.14 when treated with 100, 110 and $120^{\circ}C$, respectively. Values of b also were increased from 27.68 of control to 33.61, 33.61 and 37.42 when treated with 100, 110 and $120^{\circ}C$, respectively. Values of total color in RGWEs treated with high temperatures, E, were finally increased by values of a and b.

• Journal of Biosystems Engineering
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• 제29권1호
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• pp.37-44
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• 2004

This study was conducted to develop a new drying method far reducing the drying cost and time and to investigate the drying characteristics of oak mushroom. A far infrared dryer of down draft air flow type used for this experiment can control the drying parameters, such as far infrared heater temperature and aeration velocity. The far infrared drying tests were performed at aeration velocities of 0.3 and 0.6m/s under the temperature of 90 and 100$^{\circ}C$ in for infrared heater, respectively. The results were compared and analyzed with those of an heated air drying method used as a control in terms of properties representing the drying characteristics. such as shrinkage rate, color, energy consumption amino acid components, drying rate and moisture ratio. The results obtained from this research can be summarized as follows. 1. The drying rate of far infrared drying was faster than that of heated air drying. With high temperature of far infrared heater and slow aeration velocity, the far infrared drying of down draft air flow type was superior to the heated air drying. 2. Most of far infrared drying conditions required less energy consumption than heated air drying. 3. The shrinkage rates of heated air drying and far infrared drying were decreased by 17.0% and 18.2∼19.8%, respectively. 4. The difference of color on oak mushroom surface before and after drying can be represented as $\Delta$E. $\Delta$E values of far infrared drying and heated air drying were 2.39∼4.55 and 6.77, respectively. 5. The amounts of free amino acids were higher in the far infrared than in the heated air drying. In addition the amounts of Gln and Glu generally were increased and those of Ala, Leu, and Val were decreased in order.

• 전기학회논문지P
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• 제67권2호
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• pp.82-89
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• 2018

This paper presents a novel prototype of dual mode control based phase shift ZVS PWM high frequency load resonant inverter with lossless snubber capacitors in addition to a single active auxiliary resonant snubber for electromagnetic induction heating(IH) foam metal based consumer fluid dual packs(DPA) heater. The operating principle in steady state and unique features of this voltage source soft switching high frequency inverter circuit topology are described in this paper. The lossless snubber and auxiliary active resonant snubber assisted constant frequency phase shift ZVS PWM high frequency load resonant inverter employing IGBT power modules actually is capable of achieving zero voltage soft commutation over a widely specified power regulation range from full power to low power. The steady state operating performances of this dual mode phase shift PWM series load resonant high frequency inverter are evaluated and discussed on the basis of simulation and experimental results for induction heated foam metal heater which is designed for compact and high efficient moving fluid heating appliance in the consumer pipeline systems.

• Advances in concrete construction
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• 제4권1호
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• pp.1-14
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• 2016

In this study, high performance concrete beams and prisms with high content of PFA were heated to various temperatures up to $450^{\circ}C$ at heating rates of $1^{\circ}C/min$, $3^{\circ}C/min$ and $10^{\circ}C/min$. The thermal gradient was found to increase first with the heating time until a peak value was reached and then decrease until the thermal equilibrium was reached, measured as $115^{\circ}C$, $240^{\circ}C$ and $268^{\circ}C$ for the three heating rates. Spalling occurred on some specimens when the heating temperature was over $400^{\circ}C$ for heating rates of $3^{\circ}C/min$ and $10^{\circ}C/min$. The hygric gradient was found to reach its maximum when the thermal gradient reached its peak. This study indicates that spalling of HPC could happen when the heating temperature was high enough, and both thermal and hygric gradients reached their maxima.