• Journal of Electrochemical Science and Technology
• /
• 제10권3호
• /
• pp.294-301
• /
• 2019

The quasi-solid-state hybrid electrolytes were synthesized by chemical cross-linking reaction of methacrylate-functionalized $SiO_2$ ($MA-SiO_2$) and tetra (ethylene glycol) diacrylate in aqueous electrolyte. A quasi-solid-state electrolyte synthesized by 6 wt.% $MA-SiO_2$ exhibited a high ionic conductivity of $177mS\;cm^{-1}$ at room temperature. The electrochemical $H_2$ sensor assembled with quasi-solid-state electrolyte showed relatively fast response and high sensitivity for hydrogen gas at ambient temperature, and exhibited better durability and stability than the liquid electrolyte-based sensor. The simple construction of the sensor and its sensing characteristics make the quasi-solid-state hydrogen sensor promising for practical application.

• 한국재료학회지
• /
• 제11권2호
• /
• pp.126-131
• /
• 2001

4 차 암모늄염을 형성할 수 있는 공중합체들 poly[(vinylbenzyl chloride)-co-(n-butyl acrylate)-co-(2-hydroxyethyl methacrylate)]와 poly[(4-vinylpyridine)-co-(n-butyl acrylate)-co-(2-hydroxyethyl methacrylate)]를 고분자막 습도센서의 감습재료로 사용하기 위하여 합성하였다. 습도센서는 30%RH, 60%RH 그리고 90%RH에서 평균 저항 값은 각각 8.6 M $\Omega$, 310 k$\Omega$ 그리고 12 k$\Omega$을 보여 주었다. 또한 히스테리시스는 $\pm$3%RH 안에서 나타났으며, 온도의존성 계수는 -0.37~-0.407RH/$^{\circ}C$이었다. 감습막의 조성에서 공중합체 중 n-BA와 HEMA의 도입은 저항을 증가시키는 요인이 되나 기판과의 접착성은 크게 향상되었다. 33%RH에서 85%RH로 또는 역으로 변화할 때의 응답속도는 54초이며 수중에 2시간 침적 후 저항의 변화는 +0.2%RH 이내에서 존재하였다.

• 센서학회지
• /
• 제28권5호
• /
• pp.271-276
• /
• 2019

Pure and 0.5, 1, 2, 5, and 10 at% of Mo-doped $Co_3O_4$ yolk-shell spheres were synthesized by ultrasonic spray pyrolysis of droplets containing Co nitrate, ammonium molybdate, and sucrose and their gas sensing characteristics to 5 ppm trimethylamine (TMA), ethanol, p-xylene, toluene, ammonia, carbon monoxide, and benzene were measured at $225-325^{\circ}C$. The sensor using pure $Co_3O_4$ yolk-shell spheres showed the highest response to p-xylene and very low response to TMA at $250^{\circ}C$, while the doping of Mo into $Co_3O_4$ tended to increase the overall responses of gas sensors. In particular, the sensor using 5 at% Mo-doped $Co_3O_4$ yolk-shell spheres exhibited the high response to TMA with low cross-responses to other interfering gases. The high response and selectivity of Mo-doped $Co_3O_4$ yolk-shell spheres to TMA are attributed to the electronic sensitization by higher valent Mo doping and acid-base interaction between TMA and Mo components.

• 한국전기전자재료학회논문지
• /
• 제14권2호
• /
• pp.163-168
• /
• 2001

This dissertation describes the development of a sensor for measuring microscopic displacement where we use CoFeSiB amorphous alloy magnetic ribbon having near zero magnetostrictive properties. For the development of the sensor, we first fabricate amorphous alloy magnetic ribbon, and then investigate its physical and magnetic properties. Finally, its possibility of practical application as a displacement sensor is discussed. The experimental samples were made of near zero magnetostrictive (Co$\_$0.94/Fe$\_$0.06/)$\_$9/Si$_2$B$\_$19/ alloy which were fabricated by a rapid liquid quenching method. As a results, we got amorphous alloy magnetic ribbons of 12㎛ in thickness, 10 mm in length, and 2.5 m in width. It was found that the crystallization temperature and the Curie temperature are around 451$\^{C}$ and around 441$\^{C}$ respectively. We couldn't observe any noticeable change of the impedance frequency of 10MHz, but observed the impedance change of 3.76 %/Oe at 100 MHz. The inductance was nearly stable over the frequency range of 1∼10 MHz, In addition, it was observed that the variation of the inductance and the impedance were linear within the displacement ranges of 20∼60㎛. As the results of the experiments, it is suggested that the displacement sensor which is fabricated by using amorphous alloy magnetic ribbon of (Co$\_$0.04/Fe$\_$0.06/)$\_$79/Si$_2$B$\_$19/ compound, can be used as a sensor to detect microscopic displacement.

• 대한임베디드공학회논문지
• /
• 제7권6호
• /
• pp.301-309
• /
• 2012

In this paper, a real-time monitoring system based on WSN is designed and implemented to monitor livestock growth environment information which includes the temperature, humidity and harmful gases such as $CO_{2},\;CO,\;NH_{3},\;H_{2}S$ and so on. The proposed system consists of the wireless sensor nodes, the monitoring management device, the management server and the user interface program based on PC/Smart phone. To verify the performance of the implemented system, gas measurement experiments are performed in laboratory environment by using the designed wireless sensor nodes. And it is able to estimate the concentration of gases. The implemented system is able to monitor the proposed environmental element information through the developed GUI.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
• /
• pp.369-370
• /
• 2005

LTCC (Low Temperature Cofired Ceramic) technology is one of technologies which can realize SIP (System-In-a-Package). In this paper realization of gas sensor using LTCC technology was described. In the conventional gas sensor structure, wire bonding method is generally used as an interconnection method whereas in the LTCC sensor structure, via was used for the interconnection. As sensing materials, $SnO_2$ was adopted. The effect of frit glass portion on the adhesion of the sensing material to the LTCC substrate and the electrical conductivity of the sensing material were analyzed. AgPd, PdO, Pt was added to the sensing material as an additive for improving the gas sensitivity and electrical conductivity and the effect of the amount of additives in the sensing material on the electrical conductivity was investigated. The effect of the amount of frit glass in the termination on the sensor performance, especially mechanical integrity, was considered and the crack initiation and propagation in the boundary between the sensing material and the termination was studied.

• 한국전기전자재료학회논문지
• /
• 제28권2호
• /
• pp.92-98
• /
• 2015

The magnetoelectric characteristics on layered Ni-PZT-Ni, Co, Fe composites by epoxy bonding for magnetic field sensor were investigated in the low-frequency range. The ME coefficient of Ni-PZT-Ni, Ni-PZT-Co and Ni-PZT-Fe composites reaches a maximum of $200mV/cm{\cdot}Oe$ at $H_{dc}=110$ Oe, $106mV/cm{\cdot}Oe$ at $H_{dc}=90$ Oe and $87mV/cm{\cdot}Oe$ at $H_{dc}=160$ Oe, respectively. A trend of ME charateristics on Ni-PZT-Co, Ni-PZT-Fe composites was similar to that of Ni-PZT-Ni composites. The ME output voltage shows linearly proportional to ac field $H_{ac}$ and is about 0~150 mV at $H_{ac}$=0~7 Oe and f=110 Hz in the typical Ni-PZT-Ni sample. The frequency shift effect due to the load resistance $R_L$ shows that the frequency range for magnetic field sensor application can be modulated with appropriate load resistance $R_L$. This sample will allow for a low-magnetic ac field sensor in the low-frequency (near f=110 Hz).

• 한국가스학회지
• /
• 제5권1호
• /
• pp.7-14
• /
• 2001

가정집 가스보일러 배기가스 조성에 대하여 열역학적 관점에서 해석하였고 일산화탄소 센서의 특성에 대하여 고찰하였다. 배기가스의 조성 측정으로부터 보일러 연소조건을 예측할 수 있음을 본 연구에서 제시하였다. 즉 배기가스중의 산소농도로부터 과잉 공기량을 예측할 수 있고, 배기가스중의 일산화탄소와 수소의 비율로부터 보일러 연소실 온도를 알 수 있다. 가정집에 설치되어 있는 보일러의 배기가스 조성 해석으로부터 과잉 공기량이 약 $55\~110\%$임을 알 수 있었다. 따라서 가정집 가스보일러에서 발생하는 일산화탄소는 연소가스의 유속구배에 의한 난류에 의한 국부냉각 또는 벽에 의한 국부냉각으로 등에 의하여 발생하는 것으로 사료된다. CO센서의 출력전압은 수소와 일산화탄소의 농도에 선형적으로 비례하며, 보일러에서 일산화탄소 발생을 CO센서와 연동제어로 감소시킬 수 있다.

• 한국전기전자재료학회논문지
• /
• 제18권7호
• /
• pp.628-634
• /
• 2005

We have simulated and proposed novel optical cavity, which has two elliptical mirrors, for NDIR gas sensor module and have tested it from 0 ppm to 2,000 ppm $CO_2$ concentration. The proposed sensor module shows the maximum peak voltage at 500 ms pulse modulation time, however, it shows a maximum voltage changes at 200 ms pulse duration with 18,000 times amplification gain. From 0 ppm to 2,000 ppm, the voltage difference of sensor module $({\Delta}V)$ shows 360 mV at 200 ms pulse duration and 3 sec turn-off time. The response time of designed sensor module is about 30 seconds.

• 한국자동차공학회논문집
• /
• 제21권5호
• /
• pp.151-156
• /
• 2013

The experiment was done on cars travelling at the speeds of 20km/h, 60km/h and 100km/h using the performance testing mode for chassis dynamometer. In this experiment, the relativity between the secondary waveform coming from ignition coil and exhaust emissions were measured in case of cars with failures, in oxygen sensor, spark plugs. The following results obtained by analysis of the relativity between the secondary waveform and exhaust emissions. 1) When the oxygen sensor is failure, the average value of CO emission measured was 6.8 times higher than the standard CO emission value and the average value of HC emission measured was 2.3 times higher than the standard emission level. 2) When engine parts are in failure, more fuel enters the cylinder due to longer opening duration of injector, and it tended to make CO and HC emission values increase. 3) Combustion duration, the shape of flame propagation during spark line, and the size of the discharge-induced energy were the three main elements that directly cause variations in CO and HC emission values.