• 한국정밀공학회지
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• 제20권12호
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• pp.64-72
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• 2003

This paper presents a small loading and positioning device using VCM (voice coil motor). The developed device consists of a VCM-based linear actuating system, a capacitance displacement sensor and a cantilever deflection sensing system. The trust force of the VCM proportional to applied current moves the column supported on two pairs of parallel leaf springs. The infinitesimal displacement of moved column is detected by capacitance displacement sensor with a resolution of 0.1nm and a repeatability of 1nm. Also, a micro cantilever with known stiffness (200N/m), which is mounted on the end of the column, is used as a force sensor to detect the load applied to a specimen. After the cantilever contacts with the specimen, the deflection of cantilever and the load applied to the specimen are measured by using an optical lever system which consists of a diode laser, a mirror and a PSD (position sensitive detector). In this paper, an experimental system was constructed and its actuator and sensing parts were tested and calibrated. Also, the constructed system was applied to the indentation experiment and the load-displacement curve of aluminum was obtained. Experimental results showed that the developed device can be applied for performing nano indentation.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.794-797
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• 2009

We manufactured a novel gas permeation thin film passivation by using inorganic Mg-Zn-F target which has better optical characteristics and high electronegativity. We fabricated targets in various composition ratio and formed about 200nm which is limited thickness of the flexible display. Applied to PLED device, the target which composed of $MgF_2$ and Zn at the ratio of 4:6, WVTR was reached the measurement limit of the equipment, $10^{-3}g/m^2{\cdot}day$ and the life time was increased 25 times better than PLED device which is non-passivation.

• 센서학회지
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• 제19권4호
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• pp.259-270
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• 2010

MEMS(micro electro mechanical systems) is a technology for the manufacture hyperfine structure, as a micro-sensor and a driving device, by a variety of materials such as silicon and polymer. Many study for utilizing the MEMS applications have been performed in variety of fields, such as light devices, high frequency equipments, bio-technology, energy applications and other applications. Especially, the field of Bio-MEMS related with bio-technology is very attractive, because it have the potential technology for the miniaturization of the medical diagnosis system. Bio-MEMS, the compound word formed from the words 'Bio-technology' and 'MEMS', is hyperfine devices to analyze biological signals in vitro or in vivo. It is extending the range of its application area, by combination with nano-technology(NT), Information Technology(IT). The LOC(lab-on-a-chip) in Bio-MEMS, the comprehensive measurement system combined with Micro fluidic systems, bio-sensors and bio-materials, is the representative technology for the miniaturization of the medical diagnosis system. Therefore, many researchers around the world are performing research on this area. In this paper, the application, development and market trends of Bio-MEMS are investigated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.347-348
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• 2007

On-chip micro humidity sensor, using $CN_x$ films for the sensing material, was designed, simulated, and fabricated with Op amp based readout circuit and diode temperature sensors. To compensate the temperature and other gases, two methods were applied. One is wheatstone-bridge with reference FET that eliminates other undesirable chemical species, and the other is a diode temperature sensor to compensate the temperature effect. $CN_x$ film can be a new humidity sensing material, and has a strong potential to adapt to smart sensors or multi-sensors using MEMS or nano-technology. A particular design technology for integration of sensors and systems together was proposed that whole fabrication process could be achieved by a standard CMOS process.

• BioChip Journal
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• 제12권4호
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• pp.340-347
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• 2018

$F{\ddot{o}}rster$ resonance energy transfer (FRET) is extremely sensitive to the separation distance between the donor and the acceptor which is ideal for probing such biological phenomena. Also, FRET-based probes have been developing for detecting an unamplified, low-abundance of target DNA. Here we describe the development of FRET based DNA sensor based on an accumulated QD system for detecting KRAS G12D mutation which is the most common mutation in cancer. The accumulated QD system consists of the polystyrene beads which surface is modified with carboxyl modified QDs. The QDs are sandwich-hybridized with DNA of a capture probe, a reporter probe with Texas-red, and a target DNA by EDC-NHS coupling. Because the carboxyl modified QDs are located closely to each other in the accumulated QDs, these neighboring QDs are enough to transfer the energy to the acceptor dyes. Therefore the FRET factor in the bead system is enhancing by the additional increase of 29.2% as compared to that in a single QD system. These results suggest that the accumulated nanobead probe with conjugated QDs can be used as ultrasensitive DNA nanosensors detecting the mutation in the various cancers.

• Smart Structures and Systems
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• 제31권6호
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• pp.545-559
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• 2023

Nanoparticle strips (NPS) are widely used as external reinforcers for two-way reinforced concrete slabs. However, the Structural Health Monitoring (SHM) of these slabs is a very important issue and was evaluated in this study. This study has been done analytically and numerically to optimize the placement of sensors. The properties of slabs and carbon nanotubes as composite sheets were considered isotopic and orthotropic, respectively. The nonlinear Finite Element Method (FEM) approach and suitable optimal placement of sensor approach were developed as a new MATLAB toolbox called DECOMAC by the authors of this paper. The Suitable multi-objective function was considered in optimized processes based on distributed ECOMAC method. Some common concrete slabs in construction with different aspect ratios were considered as case studies. The dimension and distance of nano strips in retrofitting process were selected according to building codes. The results of Optimal Sensor Placement (OSP) by DECOMAC algorithm on un-retrofitted and retrofitted slabs were compared. The statistical analysis according to the Mann-Whitney criteria shows that there is a significant difference between them (mean P-value = 0.61).

• 센서학회지
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• 제15권5호
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• pp.309-316
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• 2006

The $SnO_{2}$ thin film sensors were fabricated by a thermal oxidation method. $SnO_{2}$ thin film sensors were treated in $N_{2}$ atmosphere. The sensors with $O_{2}$ treatment after $N_{2}$ treatment showed 70 % sensitivity for 1 ppm $H_{2}S$ gas, which is higher than the sensors with only $O_{2}$ treatment. The Ni metal was evaporated on Sn thin film on the $Al_{2}O_{3}$ substrate. And the sensor was heated to grow the Sn nanowire in the tube furnace with $N_{2}$ atmosphere. Sn nanowire was thermally oxidized in $O_{2}$ environments. The sensitivity of $SnO_{2}$ nanowire sensor was measured at 500 ppb $H_{2}S$ gas. The selectivity of $SnO_{2}$ nanowire sensor compared with thin film and thick film $SnO_{2}$ was measured for $H_{2}S$, CO, and $NH_{3}$ in this study.

• 한국진공학회지
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• 제20권2호
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• pp.146-154
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• 2011

접착테이프 형태의 액체누설 감지 필름 센서와 이를 이용하고 경보 장치를 포함한 감지 시스템을 개발하였다. 액체누설 감지 필름형 테이프 센서는 베이스 필름층, 전도성 라인층, 보호 필름층으로 구성되며, 테이프의 두께 $300{\sim}500{\mu}m$, 폭 3.55 cm, 그리고 단위 테이프의 길이는 200 m이다. 전도성 라인층의 필름에는 3개의 전도선과 1개의 저항선이 있다. 이들은 도전성 은나노 잉크를 전자인쇄방식으로 설치한다. 이들 저항선과 전도선 사이에 액체가 누설되어 전기적으로 상호 통전되면, 두 선사이의 저항변화를 전압의 변화로 계측하여 누설 위치를 감지한다. 물을 포함한 전도성 액체에 대한 누설 위치 감지에서 길이 200 m에서 오차 범위는 ${\pm}1m$ 이내이다.

• 센서학회지
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• 제17권5호
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• pp.369-374
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• 2008

A novel fiber optic surface plasmon resonance (SPR) sensor using cyclic olefin copolymer (COC) prism with the spectral modulation is presented. The SPR sensor chip is fabricated using the SU-8 photolithography, Ni-electroplating and COC injection molding process. The sidewall of the COC prism is partially deposited with Au/Cr (45/2.nm thickness) by e-beam evaporator, and the thermal bonding process is conducted for micro fluidic channels and optical fibers alignment. The SPR spectrum for a phosphate buffered saline (0.1.M PBS, pH.7.2) solution shows a distinctive dip at 1300.nm wavelength, which shifts toward longer wavelength with respect to the bovine serum albumin (BSA)concentrations. The sensitivity of the wavelength shift is $1.16\;nm{\cdot}{\mu}g^{-1}{\cdot}{\mu}l^{-1}$. From the wavelength of SPR dips, the refractive indices (RI) of the BSA solutions can be theoretically calculated using Kretchmann configuration, and the change rate of the RI was found to be $2.3{\times}10^{-5}RI{\cdot}{\mu}g^{-1}{\cdot}l^{-1}$. The realized fiber optic SPR sensor with a COC prism has clearly shown the feasibility of a new disposable, low cost and miniaturized SPR biosensor for biochemical molecular analyses.

• 센서학회지
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• 제29권6호
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• pp.388-393
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• 2020

In this study, a PbS quantum dots (QDs)-based H₂ gas sensor with a Pd electrode was proposed. QDs have a size of several nanometers, and they can exhibit a high surface area when forming a thin film. In particular, the NH₂ present in the ligand of PbS QDs and H₂ gas are combined to form NH₃⁺, subsequently the electrical characteristics of the QDs change. In addition to the resistance change owing to the reaction between Pd and H₂ gas, the resistance change owing to the reaction between the NH₂ of PbS QDs and H₂ gas increases the current signal at the sensor output, which can produce a high output signal for the same concentration of H₂ gas. Using the XRD and absorbance properties, the synthesis and particle size of the synthesized PbS QDs were analyzed. Using PbS QDs, the sensitivity was significantly improved by 44%. In addition, the proposed H₂ gas sensor has high selectivity because it has low reactivity with heterogeneous gases such as C₂H₂, CO₂, and CH₄.