• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권5호
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• pp.278-285
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• 2006

A micro hotplate for micro gas sensor was fabricated by MEMS technology. In order to heat up the gas sensing material to a target temperature, a micro hotplate was built on the gas sensor. The sensing material was deposited on the heater and electrodes, and did not contact with the silicon base to minimize the heat loss to the silicon base. The electric power to heat up the gas sensor was measured. The temperature distribution of micro gas sensor was analyzed by a CFD program. The predicted electric power to heat up th sensing material showed a good agreement with the measured data. The design of micro gas sensor could be modified to increase the temperature uniformity and to decrease the electric power consumption by optimizing the layout of micro hotplate and electrodes.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권4호
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• pp.356-363
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• 2016

Purpose: The purpose of this study is to propose efficiency of equipment testing the luminance degradation of OLED. Methods: The degradation model of Exponential model and Stretched exponential model is analyzed by goodness of fit test using calculated R-square. The degradation model having the higher R-square is finally selected. Scale parameter and Shape parameter using the selected degradation model is estimated. The activation energy and current density n using peck model among the accelerated model is estimated. the estimated parameters are analyzed by t-test. Results: The results of t-test show that the estimated parameters on chamber and hotplate are equal statistically. we can know the similarity of the luminance degradation rate and degradation pattern on chamber and hotplate. Conclusion: The result of the degradation test on chamber and hotplate is similar. when the accelerated degradation test on the panel of the OLED TV is performed, hotplate is requiring less samples, time and cost than chamber. so the accelerated degradation test on the panel of the OLED TV using the hoplate is efficient of time and cost.

• 한국산학기술학회논문지
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• 제5권2호
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• pp.132-136
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• 2004

대기중의 NO₂ 가스 농도를 측정하기 위한 마이크로 가스센서를 MEMS 공정을 이용하여 제작하였다. WO₃와 같은 가스 감응물질을 목표 온도까지 가열하기 위해서 마이크로 핫플레이트를 가스센서에 장착하였다. 마이크로 가스센서의 열전달 현상을 상용 열유동 해석 전용 프로그램인 FLUENT를 이용하여 해석하였다. 해석 결과 실리콘 웨이퍼 기판의 온도가 거의 상온에 가까워 핫플레이트에서 발생한 열이 가스 감응물질을 효과적으로 가열하여서 가스감응물질의 열적 고립상태를 유지하고 있는 것을 알 수 있었다. 마이크로 핫플레이트의 형상을 변경함으로써 가스 감지물질의 온도 균일도를 높일 수 있다.

• 마이크로전자및패키징학회지
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• 제27권4호
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• pp.113-117
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• 2020

논문에서는 고분자 나노구조 필름의 기계적 물성을 향상하기 위하여 광열효과를 이용한 열처리 공정을 응용하여 나노임프린트로 제작된 고분자 나노구조 필름의 기계적 물성에 미치는 영향을 규명하였다. Hybrid resin과 UV 나노임프린트을 이용하여 저반사 나노구조를 성형하고 IPL (intense pulsed light)를 이용하여 열처리를 수행한 뒤, 제작된 나노구조 필름의 투과율과 내스크래치성을 평가하여 나노구조의 성형성과 기계적 물성의 변화를 관찰하였다. 나노패턴의 특성에 의해서 나노구조의 투과율은 550 nm 파장에서 97.6%로 고투과율의 기능을 확인하였으며, IPL을 이용한 열처리를 진행한 경우 Hotplate를 이용한 열처리보다 경도는 0.51 GPa로, 0.27 GPa로 열처리한 시편에 비해 1.8배 향상하였으며, 동일 실험 조건에서 탄성율은 Hotplate 이용 시 4 GPa에서 IPL 이용 시 5.9 GPa로 1.4배 증가하였다.

• ETRI Journal
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• 제30권4호
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• pp.516-525
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• 2008

This paper proposes a compact, energy-efficient, and smart gas sensor platform technology for ubiquitous sensor network (USN) applications. The compact design of the platform is realized by employing silicon-on-insulator (SOI) technology. The sensing element is fully integrated with SOI CMOS circuits for signal processing and communication. Also, the micro-hotplate operates at high temperatures with extremely low power consumption, which is important for USN applications. ZnO nanowires are synthesized onto the micro-hotplate by a simple hydrothermal process and are patterned by a lift-off to form the gas sensor. The sensor was operated at $200^{\circ}C$ and showed a good response to 100 ppb $NO_2$ gas.

• Transactions on Electrical and Electronic Materials
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• 제17권4호
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• pp.189-195
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• 2016

Micro Hotplate (MHP) is the key component in micro-sensors, particularly gas sensors. Indeed, in metal oxide gas sensors MOX, micro-heater is used as a hotplate in order to control the temperature of the sensing layer which should be in the requisite temperature range over the heater area, so as to detect the resistive changes as a function of varying concentration of different gases. Hence, their design is a very important aspect. In this paper, we have presented the design and simulation results of a meander micro heater based on three different materials - platinum, titanium and tungsten. The dielectric membrane size is 1.4 mm × 1.6 mm with a thickness of 1.4 μm. Above the membrane, a meander heating film was deposed with a thickness of 100 nm. In order to optimize the geometry, a comparative study by simulating two different heater thicknesses, then two inter track widths has also been presented. Power consumption and temperature distribution were determined in the micro heater´s structure over a supply voltage of 5, 6, and 7 V.

• Safety and Health at Work
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• 제14권1호
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• pp.107-117
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• 2023

Background: Thermophysiological comfort in a cold environment is mainly ensured by clothing. However, the thermal performance and protective abilities of textile fabrics may be sensitive to extreme environmental conditions. This article evaluated the thermal insulation properties of three technical textile assemblies and determined the influence of environmental parameters (temperature, humidity, and wind speed) on their insulation capacity. Methods: Thermal insulation capacity and air permeability of the assemblies were determined experimentally. A sweating-guarded hotplate apparatus, commonly called the "skin model," based on International Organization for Standardization (ISO) 11092 standard and simulating the heat transfer from the body surface to the environment through clothing material, was adopted for the thermal resistance measurements. Results: It was found that the assemblies lost about 85% of their thermal insulation with increasing wind speed from 0 to 16 km/h. Under certain conditions, values approaching 1 clo have been measured. On the other hand, the results showed that temperature variation in the range (-40℃, 30℃), as well as humidity ratio changes (5 g/kg, 20 g/kg), had a limited influence on the thermal insulation of the studied assemblies. Conclusion: The present study showed that the most important variable impacting the thermal performance and protective abilities of textile fabrics is the wind speed, a parameter not taken into account by ISO 11092.

• 대한한의학회지
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• 제25권4호
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• pp.8-14
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• 2004

Objective : Achyranthes japonica Nakai (AJ) has been classified as a herb that activates blood flow and clears the stagnated blood. In this study, we evaluated its anti-nociceptive and anti-inflammatory activity in animals to clarify the effect of AJ on pain or inflammation. Methods : ICR mice and Sprague-Dawley rats were pretreated with an ethanolic extract of AJ with two dosages of 200 mg/kg (p.o.) and 400 mg/kg (p.o.). Nociceptive responses of acute pain were determined by hotplate and tail-flick tests. The effects of AJ on inflammation were evaluated by flexion/extention test and mechanical hyperalgesia test in models induced by both carrageenan and Complete Freund's Adjuvant (CFA). Results : AJ showed significant analgesic effects in both hotplate and tail-flick tests at the dose of 400 mg/kg. It also produced a significant inhibition of carrageenan-induced paw edema and CFA induced arthritis in rats at the dose of 400 mg/kg. Conclusion : We have demonstrated the analgesic and anti-inflammatory properties of an 80% ethanolic extract of AJ in animals. This suggests the application of AJ in relief of pain or inflammatory disease.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.43.2-43.2
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• 2011

Single-walled carbon nanotubes (SWCNT) are transparent in the visible and show conductivity comparable to copper, and are environmentally stable. SWCNT films have high flexibility, conductivity and transparency approaching that indium tin oxide (ITO), and can be prepared inexpensively without vacuum equipment. Transparent conducting Films (TCF) of SWCNTs has the potential to replace conventional transparent conducting oxides (TCO, e.g. ITO) in a wide variety of optoelectronic devices, energy conversion and photovoltaic industry. However, the sheet resistance of SWCNT films is still higher than ITO films. A decreased in the resistivity of SWCNT-TCFs would be beneficial for such an application. We fabricated SWCNT sheet with $KAuBr_4$ on PET substrate. Arc-discharge SWCNTs were dispersed in deionized water by adding sodum dodecyl sulfate (SDS) as surfactant and sonicated, followed by the centrifugation. The dispersed SWCNT was spray-coated on PET substrate and dried on a hotplate at $100^{\circ}C$. When the spray process was terminated, the TCF was immersed into deionized water to remove the surfactant and then it was dried on hotplate. The TCF film was then treated with AuBr4-, rinsed with deionized water and dried. The surface morphology of TCF was characterized by field emission scanning electron microscopy. The sheet resistance and optical transmission properties of the TCF were measured with a four-point probe method and a UV-visible spectrometry, respectively. $HNO_3$ treated SWCNT films with Au nano-particles have the lowest 61 ${\Omega}$/< sheet resistance in the 80% transmittance. Sheet resistance was decreased due to the increase of the hole concentration at the washed SWCNT surface by p-type doping of $AuBr_4{^-}$.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.65-65
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• 2011

Single-well carbon nanotubes (SWNT) have been proposed as a promising candidate for various applications owing to their excellent properties. In particular, their fascinating electrical and mechanical properties could provide a new area for the development of advanced engineering materials. A transparent conductive thin film (TCF) has increased for applications such as liquid crystal displays, touch panels, and flexible displays. Indium tin oxide (ITO) thin films, which have been traditionally used as the TCFs, have a serious obstacle in TCFs applications. SWNTs are the most appropriate materials for conductive films for displays due to their excellent high mechanical strength and electrical conductivity. But, a bundle of CNTs has different electrical properties than their individual counterparts. In this work, the fabrication by the spraying process of transparent SWNT films and reduction of its sheet resistance on PET substrates is researched. Arc-discharge SWNTs were dispersed in deionized water by adding sodum dodecyl sulfate (SDS) as surfactant and sonicated, followed by the centrifugation. The dispersed SWNT was spray-coated on PET substrate and dried on a hotplate at $100^{\circ}C$. When the spray process was terminated, the TCF was immersed into deionized water to remove the surfactant and then it was dried on hotplate. The TCF film was then treated with ionic doping treatment, rinsed with deionized water and dried. The surface morphology of TCF was characterized by field emission scanning electron microscopy. The sheet resistance and optical transmission properties of the TCF were measured with a four-point probe method and a UV-visible spectrometry, respectively. Results, we show that 97 ${\Omega}$/> sheet resistance can be achieved with 81% transmittance at the wavelength of 550 nm. The changes in electrical and optical conductivity of SWNT film before and after ionic doping treatments were discussed.