• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.113-118
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• 2008

We have developed an integrated giant magneto resistance using not only circuit but also integrating technique with semiconductor for automobile application. It has four elements used for giant magneto resistance sensor. Ni-Fe/Cu multi layers were prepared on a glass substrate by magnetron sputtering. The dependence of magneto resistance on the thickness of the Ni-Fe and Cu layers was investigated. The MR ratio showed a saturated a peak at Cu layer $10{\AA}$, Ni-Fe layer $50{\AA}$, where the MR ratio is about 8.7% at room temperature. By means of Ni-Fe multi film and specific integrating technique, these new giant magneto resistance sensor showed excellent resistance characteristics.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.72-77
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• 2007

A pressure sensor is a sensing device to perceive inputing pressure and convert pressure with an electric signal. Currently, a domestic pressure sensor mostly uses mechanical methods. So, it uses many parts and its cost is high. Therefore, It is necessary to improve the weak points of an existing pressure sensor and develop the accurate and reliable pressure sensor using piezo resistance strain gages.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.69-71
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• 2003

The magnetic field sensor was fabricated with superconducting ceramics of YBaCuO system. The sensor at liquid nitrogen temperature showed the increase of electrical resistance by applying magnetic field. Actually the voltage drop across the sensor was changed from zero to a value more than 100 $mutextrm{V}$ by the applied magnetic field. The change in electrical resistance depended on magnetic field. The sensitivity of this sensor was 2.9 $\Omega$/T. The sensing limit was about $1.5\times$10$^{-5}$. The increase of electrical resistance by the magnetic field was ascribed to a modification of the Josephson junctions due to the penetrating magnetic flux into the superconducting material. Considering the observed properties of the superconductor with trapped magnetic flux, a magnetic sensor was fabricated to detect simultaneously both the intensity and the direction of the magnetic field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.61-65
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• 2003

A magnetic field sensor is fabricated with superconducting ceramics system The prepared material shows the superconductivity at about 95K. The sensor at liquid nitrogen temperature shows the increase in electrical resistance by applying magnetic field. Actually, the voltage drop across the sensor is changed from zero to a value more than $100{\mu}V$ by the applied magnetic field. The change in electrical resistance depends on magnetic field. The sensitivity of this sensor is 2.9 ohm/T. The increase in electrical resistance by the magnetic field is ascribed to a modification of the Josephson junctions due to the penetrating magnetic flux into the superconducting material.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.8
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• pp.351-356
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• 2014

Typical trouble patterns in solar thermal systems include working fluid leakage and freezing other than breakdown of pump. A fluid sensor for measuring electric resistance of fluid was developed and installed at the top of the collector piping in order to check the fault of solar system. Working fluid level in the pipe was determined by measuring electric resistance from a fluid sensor. On the base of this, it was confirmed that the fluid sensor diagnoses leakage of fluid. Electric resistance of propylene glycol aqueous solution was measured in the range of $0{\sim}70^{\circ}C$ and 0~40% of concentration. The response surface analysis was performed by using a central composite design, and the regression equation was derived from the relationship between electric resistance, temperature, and concentration. Through the experiment in a real solar system, we can estimate a concentration of working fluid when a pump is not operating and predict a possibility of freezing. Finally, an effective algorithm for trouble shooting was proposed to operate and maintain the solar system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.10
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• pp.668-672
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• 2014

Carbon nanotubes(CNT) has chemical stability and great sensitivity characteristics. In particular, the gas sensor required characteristics such as rapid, selectivity and sensitivity sensor. Therefore, CNT are ideal materials to gas sensor. So, we fabricated the NOx gas sensors of MOS-FET type using the MWCNT (multi-walled carbon nanotube). The fabricated sensor was used to detect the NOx gas for the variation of $V_{gs}$(gate-source voltage) and electrode changed electrode spacing=30, 60, 90[${\mu}m$]. The gas sensor absorbed with the NOx gas molecules showed the decrease of resistance, and the sensitivity of sensor was increased by magnification of electrode spacing. Furthermore, when the voltage($V_{gs}$) was applied to the gas sensor, the decrease in resistance was increased. On the other hand, the sensor sensitivity for the injection of NOx gas was the highest value at the electrode spacing $90[{\mu}m]$. We also obtained the adsorption energy($U_a$) using the Arrhenius plots by the reduction of resistance due to the voltage variations. As a result, we obtained that the adsorption energy was increased with the increment of the applied voltages.

• Korean Journal of Materials Research
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• v.13 no.11
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• pp.732-736
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• 2003

A CP-GFRP(Carbon Powder-Glass Fiber Reinforced Plastic) sensor was fabricated for fracture detection. The electric resistance of the sensor was measured on condition of various composition of carbon powders and thickness of bundle of glass fibers. The resistance of the sensor was decreased as the increase of the content of carbon powders and the TEX of the glass fibers. In the case of loading on CP-GFRP, because inner crack was propagated, the part of percolation structures was disconnected. These observations show the following results. The conduction of CP-GFRP sensor is due to percolation structure of carbon powders and increase of resistance is due to expansion of cracks.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.186-189
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• 2004

Sensor used by semiconductor process produced an MAP sensor and applied to several industry. Among those sensors divided as transducer which convert physical quantity into electrical value, piezoresistive type sensor has been studied for the properties and sensitivity of piezoresistor. In this paper, the variation of seismic mass which have been functioned as actuator moving the cantilever beam analyzed the effect on distribution of resistance change ratio and supposed the optimal shape and position of piezoresistor. The resulting are following; According to the increment of seismic mass size, the value of resistance change ratio decreased caused by improve the stiffness. Y directional piezoresistor is formed in spot of 100 m apart from cantilever edge and length of that is 800$\mu$m. To increase the sensitivity, piezoresistor is made as n-type and x-direction.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.109-111
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• 2000

A magnetic field sensor is fabricated with superconducting ceramics of Y-Ba-Cu-O system. The prepared material shows the superconductivity at about 95K. The sensor at liquid nitrogen temperature shows the increase in electrical resistance by applying magnetic field. Actually, the voltage drop across the sensor is changed from zero to a value more than 100$\mu$V by the applied magnetic field. The change in electrical resistance depends on magnetic field. The sensitivity of this sensor is 2.9 ohm/T. The sensing limit is about $1.5\times$$10^{-5}$ (=1.5$\times$$10^{-1}$ G). The increase in electrical resistance by the magnetic field is ascribed to a modification of the Josephson junctions due to the penetrating magnetic flux into the superconducting material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.115-118
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• 2003

The sensor at liquid nitrogen temperature showed the increase of electrical resistance by applying magnetic field. Actually, the voltage drop across the sensor was changed from zero to a value more than $100\;{\mu}V$ by the applied magnetic field. The change of electrical resistance depended on magnetic field. The sensitivity of this sensor was $2.9\;{\Omega}/T$. The sensing limit was about $1.5{\times}10^{-5}\;T$. The increase of electrical resistance by the magnetic field was ascribed to a modification of the Josephson junctions due to the penetrating magnetic flux into the superconducting material. Considering the observed properties of the superconductor with trapped magnetic flux, a magnetic sensor was fabricated to detect simultaneously both the intensity and the direction of the magnetic field.