• 전기학회논문지
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• 제66권1호
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• pp.61-65
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• 2017

In this paper a prototype of high frequency heating power supply system based on the high frequency heating principle is designed to take the place of acupuncture, moxibustion, warm dressing treatment and some other traditional physical therapy methods. Which possess the advantages of low cost, convenient, easy operation and good effect. The high frequency heating power supply can generate a pulse voltage of more than 1KV with 300KHz switching frequency to heat the patient's skin. The skin temperature can reach to $41{\sim}42^{\circ}C$. The peak current control method is used to maintain the skin temperature in the designed range. The design of the main circuit is based on the flyback converter topology. An easier and practical design method is proposed in this paper. The power supply system prototype is verified to be stable and reliable by both the simulation and experimental results.

• 대한기계학회논문집A
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• 제28권4호
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• pp.435-442
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• 2004

This paper presents a hermetic MEMS on-chip package bonded by a closed-loop AuSn solder-line. We design three different package specimens, including a substrate heated specimen without interconnection-line (SHX), a substrate heated specimen with interconnection-line (SHI) and a locally heated specimen with interconnection-line (LHI). Pressurized helium leak test has been carried out for hermetic seal evaluation in addition to the critical pressure test for bonding strength measurement. Substrate heating method (SHX, SHI) requires the bonding time of 40min. at 400min, while local heating method (LHI) requires 4 min. at the heating power of 6.76W. In the hermetic seal test. SHX, SHI and LHI show the leak rates of 5.4$\pm$6.7${\times}$$^{-10}$ mbar-l/s, 13.5$\pm$9.8${\times}$$^{-10}$ mbar-l/s and 18.5$\pm$9.9${\times}$$^{-10}$ mbar-l/s, respectively, for an identical package chamber volume of 6.89$\pm$0.2${\times}$$^{-10}$. In the critical pressure test, no fracture is found in the bonded specimens up to the applied pressure of 1$\pm$0.1MPa, resulting in the minimum bonding strength of 3.53$\pm$0.07MPa. We find that the present on-chip packaging using a closed AuSn solder-line shows strong potential for hermetic MEMS packaging with interconnection-line due to the hermetic seal performance and the shorter bonding time for mass production.

• 환경위생공학
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• 제18권3호통권49호
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• pp.1-10
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• 2003

This study was aimed to investigate the influence on the vicinity by air pollutant generated from facility of the district heating located in local small town. We selected the seven areas arround the surroundings of facility of the district heating, compared the air quality evaluated before and after operations of the facility, and estimated the diffusion of air pollutant exhausted from the facility using a ISC model. The result was that the concentration of TSP before and after operations of the facility was 89${\sim}$94${\mu}$g/m$^3$,and 72${\sim}$81${\mu}$g/m$^3$, respectively and the latter showed a decline in concentration. Also, there was no relationship between straight distance from the facility of the district heating and the concentration of TSP. This result was applicable to cases of PM-10 and SO$_2$. We also investigated the influence on the air around the neighbored area by air pollutant produced from facility of the district heating using ISCLT3 model. The adding-concentrations of TSP, SO$_2$,NO$_2$, and CO were 0.0019${\sim}$0.00183${\mu}$g/m$^3$, 0.0029${\sim}$0.5648ppb, 0.2924${\sim}$l.9837ppb,and 0.0087${\sim}$0.0590ppb, respectively. It is predicted that each concentration is added to pollutant exhausted from facility of the district heating and is about 1/100${\sim}$1/180,000 of present air quality. This has a tiny influence on general air quality. According to this analysis, the concentration of air pollutant is less effected to pollutants expected by the facility of the district heating than other pollutants emitted from mobil source or industrial complex, and etc.

• Bulletin of the Korean Chemical Society
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• 제16권2호
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• pp.96-101
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• 1995

The optical properties of individual 3-to 14-micron diameter CdS crystalline spheres embedded in poly(methyl methacrylate) were studied using elastic scattering. The presence of well defined sharp peaks in the 550 to 600 nm elastic scattering spectra confirmed that each microcrystal acts as an optical cavity with cavity quality factors exceeding 104. Such natural resonator microcrystals should lead to greatly enhanced local field effects near the surface of CdS, quantum electrodynamic modification of optical transition rates of nearby species and altered photochemistry. Absorptive heating following high intensity laser irradiation was found to induce a transient washout of the high Q modes.

• The Korean Journal of Ceramics
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• 제2권1호
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• pp.48-53
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• 1996

Ion beam assisted crystallization behavior of sol-gel derived $PbTiO_3$ thin films, deposited on bare silicon(100) substrates by spin-casting method, has been investigated. Ar ion bombardment was directly conducted on the spincoated film surface with or without heating the film from room temperature to $300^{\circ}C$. Ion dose was changed from $5{\times}10^{15}$ to $7.5{\times}10^{16}$ $Ar^-/cm^2$. Formation of (110) oriented perovskite phase was obseerved with ion dose above $5{\times}10^{16}\; Ar^+/cm^2$. Crystallization of $PbTiO_3$ thin film could be enhanced with increasing the Air ion dose, or heating the substrate during ion bombardment. Crystallization of the $PbTiO_3$ films by ion bombardment was related to the local heating effect during ion bombardment.

• 설비공학논문집
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• 제24권6호
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• pp.509-514
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• 2012

In this research, a heat pump system with a heat source network is suggested which utilizes solar heat and ground heat as heat source for cooling and heating. This paper describes the summary of the suggested system and the results of the annual energy simulation. The heating and cooling loads, the electric consumption and the COP were calculated by TRNSYS 16 and evaluated in the cases of different local conditions and different system compositions. In the results, the superiority of the suggested system has been quantitatively evaluated comparing with the conventional heat pump system using one heat source. Furthermore, it was more significant in cold climate, in which the heating COP was 146% increased compared the air source heat pump system, than it in subtropical climate, 119% increased.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.588-592
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• 2006

PV Thermal combined system produces the electricity and thermal energy which are needed for buildings. The system removes heat from PV module through air or liquid, so that its efficiency will be improved. The heat as the forms of hot air or hot water can be utilized for building use, like space heating and hot water. This paper describes the concept of PV Thermal combined system and its research and development trend at local and international levels. This materials can be used as a fundamental study source about PV Thermal combined system to apply fur building space heating.

• 한국기계가공학회지
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• 제19권1호
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• pp.1-10
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• 2020

This study deals with the fabrication and thermal characterization of planar heating elements attached to the backside of the reflector used in the electrodeless lamp of a freezer. We tried to solve the problem of the local heat generation of the linear heating element that occurs about 50℃. The homogeneous dispersion and manufacturing excellence of the planar heating element produced were confirmed through SEM and EDS. In addition, the test specimens was prepared according to the change in the ratio of carbon fiber to the basis weight of the planar heating element, and a sample having a basis weight of 50g/㎡ having a content ratio of carbon fiber of 70% was selected. That sample showed low surface resistance of 4.3Ω/sq and high temperature of about 81℃ at 6V. Durability was confirmed by performing repeated bending evaluation of 3000 cycles for the sample. Large area test specimens were prepared to be applied to the actual reflector, insulated by EVA film and analyzed for their thermal characteristics. From 13V application, the temperature of the linear heating element was higher than 50℃ and the average temperature of 68℃ was maximum at 18V.

• 한국의류학회지
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• 제41권4호
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• pp.687-697
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• 2017

To figure out an appropriate pressure level for a body warming base layer, human responses were observed when the pattern reduction of base layers varied. Under the condition of $2^{\circ}C$, 60% RH, 0.1m/s, ten male subjects participated in the experiment with four sizes of experimental vests where heating pads were attached. The subjective evaluations of the heating vests with different sizes were reported using 7 or 9 point scales. We simultaneously observed chest, abdomen and scapula skin temperatures and microclimate humidity. It was found that the tight pattern as in the case of A or B provided a warmer subjective sensation and skin temperature than C or D; however, there were no differences in skin temperature at the chest. Eventually, the chest temperature decreased after about 30 mins of heating; however, temperature of abdomen increased and indicated that heating with two commercial pads used was inadequate for whole body warming. The pressure sensation of 'tight' was improved after warming the abdomen in a cold environment. Overall, the gaps beyond the original circumference of the abdomen, as in C or D, were not desirable for the local heating of abdomen under the conditions of this experiment where walking was included in the protocol. The experiment garment B with nude waist circumference was the best, and D with the largest ease, was the worst for a comfortable warming vest.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.119-125
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• 2004

Radiant tube heaters are widely used for indirect heating in heat treatment processes such as continuous annealing line(CAL) or continuous galvanizing line(CGL). Main issues for radiant tube are temperature uniformity, lifetime, thermal efficiency. To achieve higher heat release, the radiant tubes are fired at a higher fuel rate and therefore local overheating occur. A numerical simulation based on a commercial code FLUENT has been performed to investigate local overheating of radiant tube heaters. To minimize local overheating, the effects of radiating fins, flue gas recirculation(FGR), two-stage combustion were investigated. More uniform temperature distribution was achieved in the longitudinal direction within the tube with radiating fins and this contributed to increase the life of radiant tubes. Furthermore, the radiant tube with radiating fins was proven to be more efficient than the one without fins. The effects of flue gas recirculation and two stage combustion on the efficiency of the radiant tube were also considered and the results were presented.