• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.05b
• /
• pp.17-20
• /
• 2000

This paper describes on the fabrication and characteristics of hot-film type micro-flowsensors integrated with Pt-RTD's and micro-heaters on the Si substrate, in which MgO thin-films were used as medium layer in order to improve adhesion of Pt thin-films to $SiO_2$ layer, The MgO layer improved adhesion of Pt thin-films to $SiO_2$ layer without any chemical reactions to Pt thin-films under high annealing temperatures. In investigating output characteristics of the fabricated micro-flowsensors, the output voltages increased as gas flow rate and its conductivity increased due to increase of heat-loss from sensor to external. Output voltage was 82 mV at $N_2$ flow rate of 2000 seem/min, heating power of 1.2W.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.291-292
• /
• 2010

In this study, high-strength concrete mixtures were made with blast-furnace slag of 50% and 70% replacement level to evaluate material properties including compressive strength development, adiabatic temperature rise, autogenous shrinkage and chloride-ion migration coefficient. Test results showed that the use of high percentage blast-furnace slag in high-strength concrete can reduce heat of hydration and chloride-ion migration coefficient, result in control thermal cracking and improve durability performance especially under high corrosive environment.

• Journal of the Microelectronics and Packaging Society
• /
• v.13 no.1 s.38
• /
• pp.31-35
• /
• 2006

This paper is studied on a protective control system for electrical fire used electrical characteristics of SCR and multilayer-type PTC thermistor. The PTC thermistor has characteristic or positive resistivity temperature coefficient according to the temperature variation, which is construction of a regular square and cube demarcation with $BaTiO_{3_}$Ceramics of positive temperature coefficient. Also PTC shows the phenomenon which is rapidly increased in the resistivity if the temperature is increased over Curie temperature point. This paper is proposed on a protective control system used multilayer-type PTC which is protected from electrical fire due to electric short circuit faults or overload faults. Some experimental results of the proposed apparatus is confirmed to the validity of the analytical results.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.4 no.1
• /
• pp.3-12
• /
• 1967

This study has been endeavored to deposit resistance films of tin oxide on the cylindrical Pyrex glass rods. In this report, at first an outline of the film formation is described and later some electrical properities of the resistance films manufactured through new method is discussed in detail. Because the new method which is called, "Chemical Vapour Reaction Process", is not only easy to get stable resistance films, but also doesn't need vacuum systtem, it seems to be a promising fundamental process to go into flow system mass production. Electrical properties of resistance films made by the new mathod are similar to or surpassing those by provious method (for example splay method). The top data thus obtained shows that surface resistivity is 25ohm/sq. with 12 ppm in temperature coefficient of resistor. resistor.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2022.11a
• /
• pp.188-190
• /
• 2022

본 연구에서는 정전류(Constant Current) 방식에 전압강하법을 이용하여 접촉저항 측정 시스템을 구현하고 측정값을 블루투스 통신을 통해 안드로이드 운영체제에서 확인할 수 있도록 앱을 개발한다. 측정가능한 범위로 0 Ω에서 10.24 Ω 사이의 접촉 저항을 MCP3424 18 bit 분해능 ADC를 사용하여 측정할 수 있도록 설계하였다. 기존에는 반고정 저항과 별도의 전류계를 이용하여 정전류를 설정하였으나, 본 연구에서는 측정의 정밀도 및 편리성 개선을 위해 0.1% 고정밀 고정저항을 병렬로 4개 연결하여 구현하였으며, 또한 1:1 Unity Gain Buffer를 구성하고 Ultra High Precision Z-Foil 방식으로 오차 0.01%, 온도 계수 0.05 ppm/℃ 저항을 사용하여 실제로 측정한 샘플 저항 값의 결과를 확인하였다.

• Journal of Bio-Environment Control
• /
• v.6 no.3
• /
• pp.205-215
• /
• 1997

An accurate transpiration model for greenhouse tomato crop, which is liable to transpiration depression and yield loss because of low solar radiation and high humidity, could be an efficient tool for the optimum control of greenhouse climate and for the optimization of Irrigation scheduling. The purpose of this study was to develop transpiration model of greenhouse tomato and to carry out the experimental verification. The formulas to calculate the canopy transpiration and temperature simultaneously were derived from the energy balance of canopy. Transpiration and microclimate variables such as net radiation, solar radiation, humidity, canopy and air temperature, etc. were simultaneously measured to estimate parameters of model equations and to verify the suggested model. Leaf boundary layer resistance was calculated as a function of Nusselt number and stomatal diffusive resistance was parameterized by solar radiation and leaf-air vapor pressure deficit. The equation for stomatal diffusive resistance could explain more than 80％ of its variation and the calculated stomatal diffusive resistance showed good agreements with the measured values in situations independent of which the constants of the equation were estimated. The canopy net radiation calculated by Stanghellini's model with slight modification agreed well with the measured values. The present transpiration model, into which afore-mentioned component equations were assembled, was found to predict the canopy temperature, instantaneous and daily transpiration with considerable accuracy in greenhouse climates.

• Journal of Sensor Science and Technology
• /
• v.3 no.1
• /
• pp.68-77
• /
• 1994

Grid type 70Ni-30Co thin films on slide glass at $250^{\circ}C$ has been fabricated to develope. From fabricated sensors using above process, we investigated the relation of temperature, resistivity, line width to magnetoresistance and we obtained the following results after observation of coercive force, saturated magnetization, maxium usable sensitivity, delay time, slew rate, white noise, resolution of the sensors. We confirmed that the $600{\AA}$ thin film at $250^{\circ}C$ formed crystalized magnetic anisotropy spontaneously and the sensor using the thin film had capability of detecting magnetic field with sensitivity of 230 nT. In these devices, the magnetoresistance change was increased linearly in ${\pm}10$ Oe range, and the magnetoresistance effect was increased when the ratio between line width and length was increased. When the devices was soldered using indium, the temperature-resistivity coefficient showed $8{\times}10^{-3}/deg$ and increased during the specific properties as magnetic field sensor were weakened. In this studies, the coercive forces of the films were about 5.1 A/cm and saturated magnetizations were 0.64 T, and the delay time in these devises was $5{\mu}s$ and slew rate showed 0.39 $Oe/{\mu}s$ and white noise was -120 dB.

• Journal of Energy Engineering
• /
• v.10 no.2
• /
• pp.120-131
• /
• 2001

최근 세라믹 필터에 대한 연구는 열악한 환경 및 산성가스에 대한 저항성으로 인해 고온 가스 여과에서 가장 전망 있는 기술로 부각되는 시점에 있다. 본 연구의 목적은 탄화규소(SiC) 세라믹 캔들 필터를 사용하여 IGCC와 PFBC의 새로운 전력생산 공정에서 배출되는 먼지를 제거하기 위한 필터성능을 조사하기 위함이다. 필터의 성능 평가는 고온.고압.고온.상압 조건에서 이루어졌으며 필터의 압력강하, 먼지 제거효율, 저항 계수, 그리고 열적.기계적 저항성 등을 파악하였다. 길이 30cm, 60cm 필터에 2종류의 먼지(코크스와 물유리 공정)를 이용하여 나타난 먼지 제거효율은 99.9% 이상을 보였으며 필터의 평균 기공 크기가 감소함에 따라 압력강하가 증가함을 확인하였다. 또한 탄화규소 세라믹 필터의 성능은 내부압력이 증가할수록 압력강하가 감소하고 유량이 증가할수록 압력강하가 증가함과 특히 유체에 대한 압력강하 변화는 온도의 영향보다는 상대적으로 내부압력에 더 많은 영향을 받음을 확인하였다.

• Proceedings of the KAIS Fall Conference
• /
• 2010.05a
• /
• pp.153-155
• /
• 2010

실리콘 태양전지의 pn 접합 계면특성을 조사하기 위해서 p형 실리콘 기판 위에 전기로를 이용한 $POCl_3$ 공정을 통하여 n형의 불순물을 주입하여 pn접합을 만들었다. n형 불순물의 확산되어 들어가는 공정시간이 길고 공정온도가 높을수록 면저항은 줄어들었다. n형 불순물의 주입이 많아질수록 pn 접합 계면에서의 전자친화도가 줄어들면서 면저항은 감소되었다고 할 수 있다. n형 반도체의 페르미레벨이 높아지면서 공핍층도 생기지만 n형 불순물이 많아지면서 공핍층의 폭은 점점 좁아지고 쇼키 장벽의 높이도 낮아지면서 자유전자와 홀 쌍의 이동이 쉽게 이루어지게 되었다. n형의 불순물 확산공정시간이 긴 태양전지 셀에서 F.F. 계수가 높게 나타났으며, 효율도 높게 나타났다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.4
• /
• pp.352-356
• /
• 2007

The Ni/Cr/Al/Cu (51/41/4/4 wt%) thin films were deposited by using DC magnetron sputtering method for the application of the resistors having low TCR (temperature coefficients of resistance) and high resistivity from the former printed-results[3]. The TCR values measured on the as-deposited thin film resistors were less than ${\pm}10\;ppm/^{\circ}C$ and $-6{\sim}+1\;ppm/^{\circ}C$ after annealing and packaging process. The TCR values were $-3{\sim}1\;ppm/^{\circ}C$ (ratio of variation : about 0.02 %) and $-30{\sim}20\;ppm/^{\circ}C$ (ratio of variation : about $0.5{\sim}1\;%$) for the thermal cycling and PCT (pressure cooker test), respectively. It was confirmed that the reliability properties of the thin film resistor were good for electronic components.