• 제목/요약/키워드: Room-temperature operation

검색결과 241건 처리시간 0.027초

Design of Semiconducting Gas Sensors for Room-Temperature Operation

  • Song, Young Geun;Kim, Gwang Su;Ju, Byeong-Kwon;Kang, Chong-Yun
    • 센서학회지
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    • 제29권1호
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    • pp.1-6
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    • 2020
  • Gas sensors that operate at room temperature have been extensively studied because of sensor stability, lift time, and power consumption. To design effective room-temperature gas sensors, various nanostructures, such as nanoparticles, nanotubes, nanodomes, or nanofibers, are utilized because of their large-surface-to-volume ratio and unique surface properties. In addition, two-dimensional materials, including MoS2, SnS2, WS2, and MoSe, and ultraviolet-activated methods have been studied to develop ideal room-temperature gas sensors. Herein, a brief overview of state-of-the-art research on room-temperature gas sensors and their sensing properties, including nanostructured materials, two-dimensional materials, the ultraviolet-activated method, and ionic-activated gas sensors, is provided.

단열재 개선을 통한 PKG-A Water Jet Room 온도저감 연구 (A Study on the Internal Temperature Reduction of PKG-A Water-jet-room by Substituting Heat Insulation Materials)

  • 정영인;최상민
    • 품질경영학회지
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    • 제47권3호
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    • pp.425-435
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    • 2019
  • Purpose: The purpose of this study was to resolve the Naval ship's Local Operation Panel(LOP) malfunction problems which caused by overheating in summer season and dispatching to equatorial regions. Methods: Instead of using dual type heat insulation materials(consist with ceramic wool and glass wool), aerogel heat insulation materials were used for decreasing heat emissions from gas-turbine heat waste steam pipes passing water-jet- room. Experiment and Computational analysis of heat flow were conducted to analyze the internal room temperature changes. Results: The results of this study are as follows; The aerogel heat insulation materials suppress heat emission more efficiently than dual type insulation materials. The cold surface temperature of insulation was far more decreased and internal room, LOP surface temperature also showed significant results too. Conclusion: The substituted heat insulation materials appeared remarkable performance in decreasing room temperature that it could be used for suppressing the LOP overheatings and malfunctions.

공동주택에서 바닥복사냉방의 적정 운영방안에 관한 연구 (A Study on the Operation Strategy of Radiant Floor Cooling in Apartment Buildings)

  • 조영흠;석호태;여명석;김광우
    • 설비공학논문집
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    • 제16권6호
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    • pp.574-583
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    • 2004
  • In this study, the operation strategy of the radiant floor cooling is evaluated in terms of indoor environmental conditions and energy consumption through simulations using the TRNSYS comparing the existing cooling operation. The operation strategy during continuously operated for cooling is proposed that a representative room had additional equipments and other rooms were operated with only a radiant floor cooling system and that system and control method for cooling are varied with period while intermittently operated for cooling. Specifically, when there are no people in the room, rooms were operated by only radiant floor cooling system using cooling storage and when people are occupied, rooms were operated by dehumidification and supplementary cooling device with radiant floor cooling system. The results of this study show that proposed operation strategy can stably maintain the set room air temperature and can reduce the energy consumption compared to the existing cooling method during continuously operated for cooling. While intermittently operated for cooling, the difference of set room air temperature by proposed operation strategy does not happen, satisfying comfort standards and the radiant floor cooling can expect to supply stable electric power because of decreasing demand for peak electric power of energy consumption.

실온동작 세라믹 가스센서의 제작 및 특성 (Fabrication of Ceramic Gas Sensors at Room Temperature and Characteristics)

  • 정재업;윤여경;이성필
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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    • pp.814-817
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    • 2003
  • As additive Pt of a little to $SnO_2$ that gas sensing property is superior oxide-semiconductor material to fabricate gas sensor that operation is possible at room temperature and fabricated ceramic gas sensing devices. And, the change amount and sintering temperature of addition material investigated gas sensitivity by change of operation temperature, humidity relativity, Long-term stability and hysteresis. And achieved SEM and XRD analysis for characteristics searching examination of devices.

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태양열을 이용한 흡수식 냉방기의 동특성 시뮬레이션 (Dynamic simulation of a solar absorption cooling system)

  • 정시영;조광운
    • 설비공학논문집
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    • 제10권6호
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    • pp.784-794
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    • 1998
  • The present study has been directed at developing thermal models to investigate the dynamic behavior of a solar cooling system including an absorption chiller, solar collectors, a hot water storage tank, a fan coil unit, and the air-conditioned space. The operation of the system was simulated for 8 hours in two different operation modes. In the mode 1, the system operated without any capacity control.0 the mode 2, an auxiliary boiler supplied heat to the generator if hot water temperature became lower than a certain value. Moreover, the mass flow rate of hot water to the generator was controlled by comparing the instantaneous room air temperature with the design value. The variation of temperature and concentration in the system components and that of heat transfer rates in the system were obtained for both modes of operation. It was found that the room temperature was maintained near the desired value in the mode 2 by supplying auxiliary heat or controlling the mass flow rate of hot water, while the deviation of room temperature was quite great in the mode 2.

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Room-temperature Magnetotransport in Degenerately Doped GaAs:(Mn,Be) by Virtue of the Embedded Ferromagnetic Clusters

  • Yu, Fu-Cheng;Kim, Do-Jin;Kim, Hyo-Jin;Ihm, Young-Eon
    • Journal of Magnetics
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    • 제10권3호
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    • pp.103-107
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    • 2005
  • Magnetotransport is a prerequisite to realization of electronic operation of spintronic devices and it would be more useful if realized at room temperature. The effects of Be codoping on GaMnAs on magnetotransport were investigated. Mn flux was varied for growth of precipitated GaMnAs layers under a Be flux for degenerate doping via low-temperature molecular beam epitaxy. Magnetotransport as well as ferromagnetism at room temperature were realized in the precipitated GaAs:(Mn,Be) layers. Codoping of Be was shown to promote formation of MnGa clusters, and annealing process further stabilized the cluster phases. The room-temperature magnetic properties of the layers originate from the ferromagnetic clusters of MnGa and MnAs embedded in GaAs. The degenerately doped metallic GaAs matrix allowed the visualization of the magnetotransport through anomalous Hall effect.

GaAs MESFET의 최대 트랜스컨덕턴스를 위한 고온특성 (High Temperature Characteristics of GaAs MESFETs for Maximum Transconductance)

  • 원창섭;김영태;한득영;안형근
    • 한국전기전자재료학회논문지
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    • 제14권4호
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    • pp.274-280
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    • 2001
  • This paper presents transconductance (g$\_$m/( characteristics of GaAs MESFET's at high temperatures ranging from room temperature to 350$\^{C}$. GaAs MESFET of 0.3x750[㎛] gate dimension has been used to obtain the experimental data. Gate to source voltage(V$\_$GS/) has been controlled to obtain the temperature dependent characteristics for maximum transconductance g$\_$mmax/ of the device. Furthermore g$\_$mmax/ and expected g$\_$m/ have been traced with temperatures ranging from room temperature to 350$\^{C}$ also by compensating for C$\_$GS/ to maintain the optimum operation of the device. From the results, V$\_$GS/decreases as the operating temperature increases for optimum operation of the transconductance. Finally V$\_$GS/ has been optimized to trace g$\_$mmax/ and enhances the decreased g$\_$m/ with different temperatures.

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궤도차량용 보조동력장치 엔진룸 내부 열유동 특성에 관한 연구 (A Study on Thermal and Fluid Characteristics inside Engine Room of Auxiliary Power Unit for Tracked Vehicle)

  • 이태의;서정세;정상환;박영식
    • 한국정밀공학회지
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    • 제26권12호
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    • pp.85-93
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    • 2009
  • This research is intended to grasp the characteristics of heat flow inside auxiliary power device engine room to obtain the design basic data through numerical analysis and experiment. For experiment cost reduction, numerical analysis was done to obtain quantitative data by observing the change in temperature distribution of major parts according to changes in normal condition, incompressible condition, engine surface heat emission rate and absorption temperature with the use of commercial STAR-CD. The experiment was done by grasping the temperature distribution of major interested parts inside engine room in loaded and unloaded conditions during engine operation. The temperature distribution data here will serve as useful design data during APU engine room designing.

화상환자의 수술 중 저체온 발생 빈도와 체온변화에 영향을 미치는 요인 (Incidence of Hypothermia and Factors Associated with Body Temperature Changes during Surgery in Burned Patients)

  • 배혜영;김현정
    • Journal of Korean Biological Nursing Science
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    • 제18권4호
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    • pp.231-238
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    • 2016
  • Purpose: The study aimed to evaluate the changes of body temperature and to identify the factors related to changes during surgery in burned patients. Methods: A retrospective study was conducted by reviewing the medical records of 439 adult burned patients who had a surgery under general anesthesia at the Burn Center of a university hospital. Results: After surgery, body temperature of the burned patients declined from $36.6^{\circ}C$ to $35.2^{\circ}C$; 52.2% were hypothermia. There were significant differences in the changes of body temperature according to the participants' characteristics including American society of anesthesiologists physical status, type of burn injury, total burn surface area, range of exposure, operation time, anesthesia time, amount of fluid, blood transfusion, use of tourniquet, and the method of warming therapy. Factors that influence the temperature changes were total burn surface area (${\beta}=0.26$), operation time (${\beta}=0.25$), amount of fluid (0.20), and warming therapy including 'Room temperature setting + Heated circuit + Hot line'(${\beta}=0.09$) and 'Room temperature setting+one of others'(${\beta}=0.08$). Conclusion: Burned patients experienced a decrease of their body temperature during surgery despite of warming therapy. A nursing protocol is needed to provide an appropriate warming therapy based on their characteristics in burned patients.

간헐공조 전시관내 유물 진열장의 온·습도 환경 분석 (Analysis for Temperature and Relative Humidity of Showcase in Exhibition Hall Operated Intermittent Air Conditioning)

  • 이선명;임보아;김서진
    • 보존과학회지
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    • 제29권4호
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    • pp.311-320
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    • 2013
  • 조사 대상인 유물 진열장은 온도 변화에 대응한 조온기능이 미약한 반면 조습 능력이 비교적 높았다. 유물 진열장 내부의 연평균 온 습도는 $18.8^{\circ}C$, 60.3% 로 전시실에 비해 온도는 낮고 습도는 높은 분포를 나타냈다. 또한 온도는 계절변화에 따라 변동률이 높은 반면 습도는 계절별 평균값이 59~61%로 일정하게 유지되었다. 여름철에는 전시실과 마찬가지로 고온고습 분포를 나타냈고 공조기 가동에 따른 온도의 하강은 습도를 상승시켰으며. 겨울철에는 공조기 가동에 따라 전시실과 유물 진열장 간 온 습도의 차이가 커져 수분 문제가 제기되었다. 유물 진열장 내부 온 습도에 대한 PI는 18.0%로 전시물 보존을 위한 적정 온 습도 조성률이 매우 저조하였다. 특히 여름철과 겨울철은 PI가 1% 미만으로 진열장 내 철저한 온습도 관리가 필요할 것으로 판단된다.