• Nano
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• 제13권10호
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• pp.1850122.1-1850122.6
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• 2018

Vertically aligned $WO_3$-CuO core-shell nanorod arrays for $NH_3$ sensing are prepared. The sensor is fabricated by preparing $WO_3$-CuO nanorod arrays directly on silicon wafer with interdigital Pt electrodes. The $WO_3$-CuO nanorod arrays are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The sensor based on the vertically aligned $WO_3$-CuO nanorod arrays exhibits ultrasensitive $NH_3$ detection, indicating p-type behavior. The optimum sensing temperature is found to be about $150^{\circ}C$. Both response and recovery time to $NH_3$ ranging from 50 ppm to 500 ppm are around 10-15 s. A possible $NH_3$ sensing mechanism of the vertically aligned hybrid nanorod arrays is proposed.

• 한국음향학회지
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• 제35권5호
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• pp.403-409
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• 2016

전방향 센서를 이용하는 선배열 센서의 경우, 음원의 방향이 원추각의 형태로 결정되어지므로 좌 우 구분모호성이 발생한다. 이러한 문제를 해결하기 위해 운용적인 방법과 센서 배열의 구조적인 방법에 대한 연구가 진행되었다. 최근에는 음향 벡터 센서 기반의 연구가 이루어지고 있으며, 본 논문에서는 음향 벡터 센서 기반의 빔형성 기법에서 발생하는 센서 배열의 뒤틀림에 따른 좌 우 구분 성능에 대하여 분석하였다. 음향 벡터 센서는 하나의 전방향 센서와 세 개의 지향성 센서로 구성되며, 세 개의 지향성 센서는 서로 수직 방향의 속도성분을 측정한다. 이때 센서 배열의 뒤틀림에 따른 지향성 센서 축의 정보가 정확하지 않으면 잘못된 방향의 신호를 인가하여 빔형성 기법의 성능저하가 나타난다. 따라서 센서 배열의 뒤틀림에 따른 좌 우 구분 성능저하를 분석하고 보상을 통한 빔형성 기법의 성능향상을 확인하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권12호
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• pp.571-576
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• 2002

This paper is to develop jumping ring system with three sensor arrays and to control levitated ring using dynamic neural mode. Placing an aluminum ring on the core and switching on an AC source causes the ring to jump in the air due to induced currents. The educational system is composed of 40th optical sensor array, encode circuit, 89C51 microprocessor and control board. The control board consists of power IC, and phase controller. Real time process is present to obtain a height of levitated ring for three different sensor arrays. Based on the educational system and the proposed dynamic neural mode, the height of levitation of the ring is controlled by reference signals. This paper focuses on real system controls using the dynamic neural mode with on line learning algorithm.

• International Journal of Precision Engineering and Manufacturing
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• 제9권4호
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• pp.32-38
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• 2008

This paper describes a fast tool control (FTC)-based diamond turning process for fabricating large-area high-quality micro-lens arrays. The developed FTC unit has a stroke of $48{\mu}m$ and a resonance frequency of 4.9 kHz. Micro-lens arrays were fabricated using a micro-cutting tool with a nose radius of $50{\mu}m$. The FTC unit was integrated with a force sensor so that the initial position of the micro-cutting tool with respect to the workpiece surface could be detected through monitoring the contacting force. The length and depth of the designed parabolic micro-lens profile were $190{\mu}m$ and $20{\mu}m$, respectively. A micro-lens array was fabricated on a cylinder surface over an area of ${\phi}55 mm{\times}40 mm$.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3735-3737
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• 2011

We report a simple method for fabricating ZnO gas sensors via a sonochemical route and their $H_2$ gas sensing properties. Vertically aligned ZnO nanorod arrays as a sensing material were synthesized on a Pt-electrode patterned alumina substrate under ambient conditions. The advantage of the proposed method is a high speed of processing. The gas sensor based on ZnO nanorod arrays with large specific surface area showed a high response to $H_2$ and a detection limit of 70 ppm at $250^{\circ}C$. Also, their response and recovery time were relatively short and a complete regeneration was observed. A mechanism for sensing $H_2$ gas on the surface of ZnO nanorods is proposed.

• 센서학회지
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• 제9권4호
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• pp.307-315
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• 2000

FBG (Fiber Bragg Grating) hydrophone sensor의 arrays system을 구축하고, 수중에서 넓은 영역에 대한 다중점 신호 검출을 구현하기 위하여, WDM(Wavelength Division Multiplexing) 방법과 passive band-pass filter system을 이용하여, 설계 및 제작된 2개의 FBG transducers의 수중 음향파 신호 검출을 실행하였다. 실험 결과 수중에서 주파수 1.3 KHz대까지 다중점에 대하여, 주파수 신호가 각각 다른신호의 검출이 가능하였다. 따라서, 제작된 FBG transducers을 이용한 hydrophone sensor arrays의 시스템 설계가 가능함을 확인하였다.

• Journal of information and communication convergence engineering
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• 제10권2호
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• pp.108-116
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• 2012

A novel approach to general linearly constrained adaptive arrays is presented to improve the nulling performance in coherent and noncoherent environments. The narrowband and broadband linearly constrained adaptive arrays are implemented to examine the array performance. It is shown that the proposed approach performs better than the conventional adaptive arrays and the nulling performance depends on the gain factor for the desired response.

• 한국정밀공학회지
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• 제30권1호
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• pp.128-133
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• 2013

Si Nanowire (Si-NW) arrays were fabricated by top-down method. A relatively simple method is suggested to fabricate suspended silicon nanowire arrays. This method allows for the production of suspended silicon nanowire arrays using anisotropic wet etching and conventional MEMS method of SOI (Silicon-On-Insulator) wafer. The dimensions of the fabricated nanowire arrays with the proposed method were evaluated and their effects on the Field Effect Transistor (FET) characteristics were discussed. Current-voltage (I-V) characteristics of the device with nanowire arrays were measured using a probe station and a semiconductor analyzer. The electrical properties of the device were characterized through leakage current, dielectric property, and threshold voltage. The results implied that the electrical characteristics of the fabricated device show the potential of being ion-selective field effect transistors (ISFETs) sensors.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
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• pp.439-442
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• 2002

We present in this Paper a microwave Power sensor fabricated by a standard CMOS process and a bulk micromachining process. The sensor consists of a CPW transmission line, a resistor as a healer, and thermocouple arrays. An input microwave heater, the resistor so that the temperature rises proportionally to the microwave power and tile thermocouple arrays convert it to an electrical signal. The sensor uses air bridged 8round of CPW realized by wire bonding to reduce tile device size and cost and to improve the thermal impedance. Al/poly-Si junctions are used for the thermocouples. Poly-Si is used for tile resister and Aluminium is for transmission line. The resistor and hot junctions of the thermocouples are placed on a low stress silicon nitride diaphragm to minimize a thermal loss. The fabricated device operates properly from 1㎼ to 100㎽\ulcorner of input power. The sensitivity was measured to be ,3.2～4.7 V/W.

• 센서학회지
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• 제25권1호
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• pp.13-19
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• 2016

Nowadays, most major automobile manufacturers are very interested, and actively involved, in developing driver alcohol detection system for safety (DADSS) that serves to prevent driving under the influence. DADSS measures the blood alcohol concentration (BAC) from the driver's breath and limits the ignition of the engine of the vehicle if the BAC exceeds the reference value. In this study, to optimize the sensor array of the DADSS, we selected sensors by using three different methods, configured the sensor arrays, and then compared their performance. The Wilks' lambda, stepwise elimination and filter method (using a principal component) were used as the sensor selection methods [2,3]. We compared the performance of the arrays, by using the selectivity and sensitivity as criteria, and Sammon mapping for the analysis of the cluster type of each gas. The sensor array configured by using the stepwise elimination method exhibited the highest sensitivity and selectivity and yielded the best visual result after Sammon mapping.