• 대한기계학회논문집
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• 제10권5호
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• pp.779-786
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• 1986

본 연구에서는 난해한 수식을 구사한 새로운 제어회로에 관한 해석이나 설계 이론에 관한 것이 아니라 지금먼저 비금속 윅을 단독으로만 실험하여 해석해와의 일치 까지의 여러 연구자의 의론에 의하여 확립된 열선유속계의 기본계측이론을 충실하게 실현하는 단순화회로로 구조가 간단하고 취급이 간편하며 저렴한 가력으로 제작 할 수 있으며 성능면에서도 고가의 기성 상품에 비하여 그다지 손색이 없는 실용적인 정온도 형 열선유속계를 개발하는 것이다.

• 한국자동차공학회논문집
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• 제5권6호
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• pp.1-12
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• 1997

In an SI engine, the characteristics of the air flow is important not only for the design of the intake system geometry but also for the accurate measurement of the induction air mass. In this study, an air flow rate measurement using the ultrasonic flow meter and hot wire flow meter was conducted at the upstream of the intake port and the throttle. At the upstream of the intake port, the pulsating flow into the cylinder affected by the pressure wave was detected directly with the flow meters instead of pressure sensors. At the upstream of the throttle, the reverse flow phenomena were showed by comparing the flow pattern measured by the hot wire air flow meter and the ultrasonic air flow meter. The results of this study can be used for the analysis of the tuning effect in the intake manifold and estimation of the error in real time measurement for the air flow rate.

• 한국유체기계학회 논문집
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• 제12권2호
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• pp.17-23
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• 2009

The program using $C/C^{++}$ which could calculate 3-D velocities from data of the flowfield obtained by a slant hot-wire has been developed. The characteristic of the exit flowfield of a circular nozzle with a curved surface was investigated. From the result, the inward-flow was verified at adjacent layers near the boundary of the exit flowfield of a circular nozzle in Id and outward-flow was sensed gradually from down-flow of Id. Similarity of the nondimensional velocity profile properlly could be obtained except near Id and the virtual origin reasonably could be obtained.

• 대한기계학회논문집B
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• 제20권1호
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• pp.295-303
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• 1996

A new temperature compensation technique for hot-wire anemometer is proposed in this article. In contrast to the available compensation techniques, a photoconductive cell is introduced here as a variable resistor in the bridge. The major advantage of adopting an active component such as photoconductive cell is that temperature compensation can be achieved by using any kind of temperature sensors, once the output of temperature sensor is given as a voltage. Thereby, the temperature compensation can be made automatically and intelligently by a computer software or a hardware device. Validation experiments using a photoconductive cell with a thermocouple-thermometer are conducted in the temperature range from 3$0^{\circ}C$ to 5$0^{\circ}C$ and the velocity ranges from 8 m/s to 18 m/s.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.273-276
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• 2006

To generate electricity from wind energy, wind turbine generally has a rotor blade. Since this rotor blade is a kind of the rotating machinery, the wake from the rotor is very Important role in the side of the aerodynamic performances. Thus the study about wake is essential to analyze wind turbine aerodynamics. In this study wake characteristics are analyzed by hot-wire probe in the K.A.F.A(Korea Air Force Academy) wind tunnel. It is possible to analyze the wake characteristics by hot-wire probe from acquiring the velocity fluctuations at given positions in the flow. This velocity data are arranged by trigger signal at same azimuth of the blade in periodic manner of the rotor blade. From this various wake characteristics are found : radial and axial position of the tip vortex, vortex core characteristics in the flow etc.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.172-175
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• 2009

n-type crystalline silicon wafers were passivated with intrinsic a-Si:H thin films on both sides using HWCVD. Minority carrier lifetime measurement was used to verify interface passivation properties between a-Si:H thin film and crystalline Si wafer. Thin film interface characteristics were investigated depending on $H_2/SiH_4$ ratio and hot wire deposition temperature. Vacuum annealing were processed after deposition a-Si:H thin films on both sides to investigate thermal effects from post process steps. We noticed the effect of interface passivation properties according to $H_2/SiH_4$ ratio and hot wire deposition temperature, and we had maximum point of minority carrier lifetime at H2/SiH4 10 ratio and $1600^{\circ}C$ wire temperature.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1427-1429
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• 2001

Polycrystalline silicon(poly-Si) films are deposited on low temperature glass substrate by Hot-Wire CVD(HWCVD). The structural properties of the poly-Si films are strongly dependent on the wire temperature($T_w$). The films deposited at high $T_w$ of 2000$^{\circ}C$ have superior crystalline properties; average lateral grain sizes are larger than $1{\mu}m$ and there at·e no vertical grain boundaries. The surface of the high $T_w$ samples are naturally textured like pyramid shape. These large grain size and textured surface are believed to give high current density when applied to solar cells. However, the poly-si films are structurally porous and contains high defect density, by which high concentration of C and O resulted within the films by air-penetration after removed from chamber.

• 대한기계학회논문집
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• 제14권3호
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• pp.734-746
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• 1990

본 연구에서는 문등이 제안한 방법에 의하여 직사각형 단면의 180˚곡관유동 에서 속도분포와 난류성분을 측정하여 단면의 종횡비 변화에 따른 유동특성과 난류특 성의 변화를 고찰하였다.

• 설비공학논문집
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• 제4권2호
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• pp.137-145
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• 1992

coefficient precisely, experiments were carried out in three categories which contain the regime of (1) constant wire temperature (2) constant fluid temperature (3) constant temperature difference between wire and fluid. Measurements were made with electrically heated circular tungsten wire placed normal to air stream at the exit of jet. Heat transfer coefficient was increased with wire temperature increasing and decreased by fluid temperaure increasing and was not changed with varying both temperature if their difference were kept constant.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.632-635
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• 2001

Microcrystalline Si films have been deposited by using five W-wire filaments of 0.5 mm diameter for hot-wire chemical vapor deposition (HWCVD). We compared the HWCVD grown films with the film exposed to transformer couple plasma system for the modification of seed layer. W-wire filament temperature was maintained below 1600$^{\circ}C$ to avoid metal contamination by thermal evaporation at the filament. Deposition conditions were varied with H$_2$dilution ratio, with and without plasma treatment. From the Raman spectra analysis, we observed that the film crystallization was strongly influenced by the H$_2$dilution ratio and weakly depended on the distance between the wire and a substrate. We were able to achieve the crystalline volume fraction of about 70% with an SiH$_4$/H$_2$ratio of 1.3%, a wire temperature of 1514$^{\circ}C$, a substrate separation distance of 4cm, and a chamber pressure of 38 mTorr. We investigated the influence of ${\mu}$c-Si film properties by using a plasma treatment. This article also deals with the influence of the H$_2$dilution ratio in crystallization modification.