• 센서학회지
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• 제24권3호
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• pp.194-201
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• 2015

The current sensor is used in industrial devices and power utilities. Core materials of these current sensors are divided into mainly two groups as silicon steel and fermalloy. Silicon steel has a wide saturation bandwidth but low sensitivity during low-current, whereas permalloy has a short saturation bandwidth but high sensitivity during low-current. In this paper, laminated silicon steel and permalloy by equal ratio is proposed to improve the linearity and saturation of current sensor. It is proved that the proposed core material has larger bandwidth than fermalloy as well as higher sensitivity than silicon steel. When comparing simulation results by FLUX 3D, the proposed method has also better performance than the previous core materials.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권9호
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• pp.676-680
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• 1999

To do breath alcohol measurement, a sensor is necessary that it can detect low alcohol gas concentration of 0.01% at least. In this work, a capacitance-type alcohol gas sensor using porous silicon layer is developed to measure low alcohol gas concentration. The sensor using porous silicon layer has some sensitivity at room temperature by very large effective surface area, but there is still much room for improvement. In this experiment, we measured the capacitance of the sensor under 254 nm UV light on the porous silicon layer, in which alcohol solution was kept in a flask at 25, 35, and $45^{\circ}C$ by a heater. As the result, the improvement of sensitivity by illuminating UV light was observed. The increasing rate of the capacitance was shown to be double more than those measured under UV-off state. It is supposed that UV light activates response of the oriental and interfacial polarizations which have slow relaxation time for AC field.

• 센서학회지
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• 제20권4호
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• pp.279-285
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• 2011

This study was carried out to apply chemical gas sensors for the identification of bad breath which is one of the important sensitive problem for the humans' daily life. Seven sensors, including five semiconductor sensors and two electrochemical sensors, were tested for the three panels three times in several conditions. The results showed that the reproducibility of sensors were generally good, and electrochemical sensors showed better reproducibility while semiconductor sensors showed better sensitivity. No rinsing before measurement showed relatively better results in terms of both sensitivity and reproducibility. Semiconductor gas sensors for hydrogen sulfide shows the highest sensitivity, and it was recommended to use the odor-free bag for the measurement of bad breath.

• 한국수소및신에너지학회논문집
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• 제8권4호
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• pp.145-154
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• 1997

Pd, Pd-Rh 게이트 MOS센서의 $H_2$, $H_2S$ 검지특성과 Pd박막의 중착조건이 감지특성에 미치는 영향에 대해서 조사하였다. rf power의 증가와 증착온도의 증가는 모두 센서의 감도와 초기반응속도를 감소시켰으며 rf power의 변화보다는 증착온도의 변화에 의한 효과가 현저하였다. Pd-Rh 센서의 경우 순수한 Pd 센서에 비해 감도가 낮았으며 Rh의 양이 증가할수록 감도는 감소하였다. Pd-Rh 센서에서 $H_2$가 $H_2S$보다 더 뛰어난 감도를 보여주었다. rf power, 증착온도, 기판의 변화가 MOS센서의 감도나 초기반응속도 등의 센서특성에 영향을 미친다는 사실을 확인할 수 있었다.

• Composites Research
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• 제17권4호
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• pp.61-67
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• 2004

Micromechanical 시험법과 음향방출을 이용하여 단일 basalt 섬유 강화 에폭시 복합재료의 비파괴 손상감지능을 평가하였다. 음향방출 센서로는 PZT 및 고분자 PVDF와 P(VDF-TrFE)를 사용하였고 단섬유 강화 시험법에서 각 센서 종류에 따른 손상감지능을 상호 비교하였다. 고분자 센서는 시편 표면에 부착시키거나 내부에 함침시켜 사용하였지만 PZT 센서는 표면에 부착하여 사용하였다. 고분자 센서를 시편 표면에 부착시킨 경우와 함침시킨 경우 감지능은 비슷하였지만 부착의 경우 debonding 신호가 많아 함침 시키는 방법이 손상감지에 더 효과적이었다. 손상 감지능은 PZT센서가 가장 높았고, 함침 및 부착 모두에서 PVDF와 P(VDF-TrFE) 센서의 손상감지능은 거의 비슷하였다.

• 환경생물
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• 제22권3호
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• pp.394-399
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• 2004

S. marcescens LSY4가 충전된 BOD센서를 제작하여 표준오염물질을 포함한 수용액의 BOD를 측정하였다. 배양시간이 9∼16시간일 때에는 배양시간에 따른 BOD센서의 감응도에 큰 차이를 나타내지 않았으며, 균체량도 0.22~0.75mg $cm^{-2}$의 범위에서는 거의 동일한 센서의 감응도를 나타내었다. 수용액의 pH가 4~9사이로 변화할 경우 센서의 감응도가 가역적으로 변화하였으나 수용액이 더 산성이거나 더 염기성이 되면 센서의 감응도가 비가역적으로 저하되었다. 수용액에 중금속이온이 첨가되면 센서의 감응도가 감소하였으며, $Zn^{2+}$나 $Cd^{2+}$보다 $Cu^{2+}$혹은 $Ag^+$가 첨가되었을 때 센서의 감응도가 더 급격히 감소하였다. 중금속에 대한 내성이 유도된 균체를 충전하였을 때 중금속이온의 첨가에 따른 센서의 감응도 감소가 크게 완화되었으며, 이런 효과는 $Cd^{2+}$내성주보다 $Cu^{2+}$내성주에서 더 현저하였다.

• 한국항행학회논문지
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• 제23권1호
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• pp.69-76
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• 2019

본 논문에서는 평면 유전체 기판의 유전율 측정을 위해 마이크로스트립 결함 접지구조를 기반으로 한 고감도 마이크로파 센서의 설계 방법에 대하여 연구하였다. 제안된 센서는 H-모양 개구의 리지 구조를 커패시터 기호 모양으로 변형하여 설계하였다. 제안된 센서의 감도를 기존의 이중 링 상보형 분할 링 공진기를 기반으로 한 센서의 감도와 비교하였다. 두 센서는 피 시험 기판이 없는 상태에서 전송 계수가 1.5 GHz에서 공진하도록 0.76 mm 두께의 RF-35 기판 상에 설계하고 제작하였다. 피 시험 기판으로 비유 전율이 2.17에서 10.2 범위에 있는 타코닉 기판 5종을 선택하였다. 실험 결과, 전송계수 공진주파수의 이동으로 측정된 제안된 센서의 감도는 기존 이중 링 상보형 분할 링 공진기를 기반으로 한 센서와 비교할 때 1.31배에서 1.62배 증가하는 것을 확인하였다.

• 조명전기설비학회논문지
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• 제29권7호
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• pp.1-7
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• 2015

In this paper, we demonstrated a polarimetric fiber pressure sensor using a polarization-diversity-loop-based Sagnac interferometer(PDLSI) composed of polarization-maintaining fiber(PMF) and a fiber Bragg grating(FBG). In order to compare the pressure sensitivity for various kinds of PMF, three kinds of bow-tie PMF were employed as sensor heads. The maximum pressure sensitivity was measured as approximately -15.07nm/MPa, and an R2 value to represent sensor linearity was measured as ~0.992 at the sensor system using corresponding PMF over a pressure range of 0-0.3MPa. An FBG was utilized and located adjacent to the PMF segment for compensating temperature-induced errors in the measurement of pressure. The pressure sensitivity of the proposed sensor was improved by approximately four times compared with the previously reported pressure sensor based on polarization-maintaining photonic crystal fiber.

• 반도체디스플레이기술학회지
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• 제14권2호
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• pp.1-7
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• 2015

In this paper, a new capacitive pressure sensor has been proposed for a displacement measurement. The new sensor is mainly composed of a gap of $5{\mu}m$ and a notch of $1{\mu}m$. And the sensor has the performance as the high sensitivity and capacitance compared with a commercial capacitive sensor. Therefore, the advantages of the new capacitive pressure sensor are good sensitivity in normal range, mechanically robust and large overload protection. The analytical model is induced for confirming the performance of the proposed sensor. In addition, FEM (finite elements method) simulation has been performed to verify the analytical model. Firstly, the displacement characteristics of diaphragm membrane were simulated by the analytical model and FEM in the case of different structure and materials. At last, through this analysis, these simulation results can be predicted the change of the performance when the device parameters are varied. And it is used as a design tool to achieve at a set of performance we desired.

• 한국소음진동공학회논문집
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• 제22권7호
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• pp.626-633
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• 2012

In this paper, sound pressure sensitivity of the fiber optic acoustic sensor according to sensor direction and mandrel material were investigated experimentally. Three different directions were selected as stand, lay, and hole. Hollow cylinder type mandrel dimension is 30 mm in outer diameter, 45 mm in length, and 2 mm in thickness, and about 50 m optical fibers were wounded on the surface of the mandrel. Non-directional sound speaker was used as a sound source. Sagnac interferometer and single mode fiber, a laser with 1,550 nm in wavelength, $2{\times}2$ coupler were used. Based on the experimental results, lay direction's sensitivity is the highest in the frequency range of 2 kHz~4 kHz. 'PTFE+carbon' material is more sensitive than PTFE in the frequency range of 5 kHz~20 kHz. Sound pressure detection sensitivity depends on the mandrel direction and material under certain frequency.