• 센서학회지
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• 제21권3호
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• pp.229-234
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• 2012

The existing permeability measurements based on pressure differential between the polymer membrane that is permeable to measure the amount of oxygen used, but these methods must be kept in a vacuum, and the measurement of the membrane with low permeability in the membrane is too time consuming. In recent years by using electrochemical method polymer membrane currents caused by the amount of oxygen is a measure of how much is used. In this study, apparatus consisting of one anode and six cathodes for multi-oxygen permeability tester used the same number of membranes produced by electrochemical oxygen permeation characteristics. In this study, one silver/silver chloride anode electrochemical method with a hexagonal sensor to put various kinds of polymer membranes with the six oxygen permeability for simultaneous measurement in real-time systems. Six cathodes (Pt), and one of the coil-shaped anode (Ag/AgCl) to form a hexagonal one of the polarographic oxygen sensor in a single measurement system by six sensors. Each sensor for making hexagonal specificity of the sensor to compensate for the conditions obtained in a pure nitrogen gas and pure oxygen gas conditions. With this study, self-developed hexagonal sensor capable of measuring sensors and oxygen permeability tester, for a multi-six different oxygen permeability characteristics of the membrane measured at the same time.

• 전기학회논문지
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• 제63권10호
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• pp.1434-1440
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• 2014

This paper describes a demosaicking method for hexagonally-structured color filter array. Demosaicking is essential to acquire color images using color filter array (CFA) in single sensor imaging. Thus, CFA patterns have been discussed in order to improve image quality in single sensor imaging after the Bayer pattern are introduced. Advancements in imaging sensor technology recently introduce a hexagonal CFA pattern. The hexagonal CFA can be considered to be a 45-degree rotational version of the Bayer pattern, thus demosaicking can be implemented by an existing method with backward and forward 45-degree rotations. However, this approach requires heavy computing power and memory in image sensing devices because of the image rotations. To overcome this problem, we proposes a demosaicking method for a hexagonal Bayer CFA without rotations. In addition, we introduce a weighting parameter in our demosaicking method to improve image quality and to unifying exiting method with our method. Experimental results indicate that the proposed method is superior to conventional methods in terms of PSNR. In addition, some optimized values for the weighting parameter are provided experimentally.

• 센서학회지
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• 제26권6호
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• pp.379-385
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• 2017

In this study, an amperometric non-enzymatic glucose sensor was developed on the surface of a glassy carbon electrode by simply drop-casting the synthesized homogeneous suspension of hexagonal boron nitride (h-BN) nanosheets with a copper metal-organic framework (Cu-MOF) composite. Comprehensive analytical methods, including field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry, were used to investigate the surface and electrochemical characteristics of the h-BN-Cu-MOF composite. The FE-SEM, FT-IR, and XRD results showed that the h-BN-Cu-MOF composite was formed successfully and exhibited a good porous structure. The electrochemical results showed a sensor sensitivity of $18.1{\mu}A{\mu}M^{-1}cm^{-2}$ with a dynamic linearity range of $10-900{\mu}M$ glucose and a detection limit of $5.5{\mu}M$ glucose with a rapid turnaround time (less than 2 min). Additionally, the developed sensor exhibited satisfactory anti-interference ability against dopamine, ascorbic acid, uric acid, urea, and nitrate, and thus, can be applied to the design and development of non-enzymatic glucose sensors.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.532-535
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• 2000

We have fabricated a sensor system for on-line monitoring the oxygen permeability and diffusivity of six different polymer films using the miniaturized 6 cathode(Ag)-single anode(Ag/AgCl) type hexagonal oxygen electrode. This system consists of multiple input front-end electronics, signal conditioning circuit using the embedded microcontroller 80C196KC, PC interface circuit and PC with the OS for microcontroller and the operating program for this system. The digital low-[ass filter was programmed and the simulated filter characteristics were enough to eliminate the noise from sensor signal. According to the experimental results, the linearity coefficients of the output voltage to oxygen partial pressure for each sensor electrode of six cathode type oxygen sensor are 0.998, 0.997, 0.998, 0.997, 0.997, 0.997 respectively, and the response times are all within 4 minutes.

• 한국분말재료학회지
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• 제26권1호
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• pp.28-33
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• 2019

The gas sensor is essential to monitoring dangerous gases in our environment. Metal oxide (MO) gas sensors are primarily utilized for flammable, toxic and organic gases and $O_3$ because of their high sensitivity, high response and high stability. Tungsten oxides ($WO_3$) have versatile applications, particularly for gas sensor applications because of the wide bandgap and stability of $WO_3$. Nanosize $WO_3$ are synthesized using the hydrothermal method. As-prepared $WO_3$ nanopowders are in the form of nanorods and nanorulers. The crystal structure is hexagonal tungsten bronze ($MxWO_3$, x =< 0.33), characterized as a tunnel structure that accommodates alkali ions and the phase stabilizer. A gas detection test reveals that $WO_3$ can detect acetone, butanol, ethanol, and gasoline. This is the first study to report this capability of $WO_3$.

• 로봇학회논문지
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• 제17권3호
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• pp.282-287
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• 2022

High shear adhesion on wet and rough surfaces and tactile feedback of gripping forces are highly important for realizing robotic gripper systems. Here, we propose a bioinspired robotic gripper with highly shear adhesion and sensitive pressure sensor for tactile feedback systems. To achieve them, we fabricated multi-walled carbon nanotube sensing layer on a thin polymeric adhesive layer of polydimethylsiloxane. With densely hexagonal-packed microstructures, the pressure sensor achieved 9 times the sensing property of a sensor without microstructures. We then assembled hexagonal microstructures inspired by the toe pads of a tree frog, giving strong shear adhesion under both dry and wet surfaces such as silicon (42 kPa for dry and ~30 kPa for underwater conditions) without chemical-residues after detachment. Our robotic gripper can prevent damage to weak or smooth surfaces that can be damaged at low pressure through pressure signal feedback suggesting a variety of robotic applications.

• 한국광학회지
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• 제30권2호
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• pp.67-73
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• 2019

본 논문에서는 다양한 배열을 가지는 기판에서의 특이 광 투과 센서 시스템의 센싱 성능을 조사하였다. 보조파장 홀 어레이 구조는 어레이의 주기와 격자 배열을 달리하여 제작하였고, 특이 광 투과 센서 시스템으로 제작한 기판에서의 투과 스펙트럼을 측정하였다. 굴절률이 다른 유전물질을 이용하여 투과 스펙트럼을 관찰한 결과 어레이의 주기가 증가할수록 센서의 민감도가 높아짐을 보았다. 또한 육각형 어레이에서 측정한 결과와 비교하였을 때 정사각형 어레이에서 센서의 성능이 향상됨을 입증하였다.

• 한국재료학회지
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• 제18권12호
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• pp.669-672
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• 2008

Well-aligned Zinc oxide (ZnO) nanowires were synthesized on silicon substrates by a carbothermal evaporation method using a mixture of ZnO and graphite powder with Au thin film was used as a catalyst. The XRD results showed that as-prepared product is the hexagonal wurzite ZnO nanostructure and SEM images demonstrated that ZnO nanowires had been grown along the [0001] direction with hexagonal cross section. As-grown ZnO nanowires were coated with glucose oxidase (GOx) for glucose sensing. Glucose converted into gluconic acid by reaction with GOx and two electrons are generated. They transfer into ZnO nanowires due to the electric force between electrons and the positively charged ZnO nanostructures in PBS. Photoluminescence (PL) spectroscopy was employed for investigating the movements of electrons, and the peak PL intensity increased with the glucose concentration and became saturated when the glucose concentration is above 10 mM. These results demonstrate that ZnO nanostructures have potential applications in biosensors.

• 센서학회지
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• 제19권5호
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• pp.337-341
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• 2010

In this work, the nanocrystalline ZnO/polycrystalline(poly) aluminum nitride(AlN)/ Si-layered structure was fabricated for humidity sensor applications based on surface acoustic wave(SAW). The ZnO film was used as a sensitive material layer. The ZnO and AlN(0002) were deposited by a sol-gel process and a pulse reactive magnetron sputtering, respectively. The ZnO sensitive films coated on AlN have a hexagonal wurtzite structure after the thin films annealed at $400^{\circ}C$, $500^{\circ}C$ and $600^{\circ}C$. The surface of the film exhibits sponginess and a nanometer particle size(below 50 nm). The largest shift in the frequency response was at approximately 200 kHz(the relative humidity: 10 %~90 %) for the structure annealed at $400^{\circ}C$. The effect of the change in the environmental temperature on the frequency response of the SAW humidity sensor was also investigated.

• 센서학회지
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• 제27권4호
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• pp.249-253
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• 2018

Infrared transparent ZnS ceramics were synthesized through hydrothermal synthesis ($180^{\circ}C$, 70 h) and sintered using a hot press process at $750^{\circ}C-1000^{\circ}C$. We carried out x-ray diffraction, scanning electron microscopy, and Fourier transform-infrared spectroscopy to confirm the optical properties of the ZnS ceramics after sintering at various temperatures. The phase of ZnS nanopowders was a single phase (cubic) without the hexagonal phase. However, as sintering temperature increased, the formation and increment of hexagonal structures was confirmed. The ZnS ceramic sintered at a temperature of $750^{\circ}C$ showed poor transmittance because it was not completely sintered and because of the pore effect. The ZnS ceramic with the highest transmittance (approximately 69%) was sintered at $800^{\circ}C$. As sintering temperature increased, transmittance gradually decreased owing to the increase in the formation of the hexagonal phase.