• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3592-3596
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• 2011

A novel poly(vinylchloride)-based membrane sensor using $N^1$,$N^3$,$N^5$-tris(2-(2,3-dihydroxybenzylamino)-ethyl)cyclohexane-1,3,5-tricarboxamide (CYCOENCAT, L) as ionophore has been prepared and explored as $Fe^{3+}$ selective electrode. The membrane electrode composed of ionophore, poly(vinylchloride) and o-nitropheyloctyl ether in the optimum ratio 4:33:63 gave excellent potentiometric response characteristics, and displayed a linear log[$Fe^{3+}$] versus EMF response over a wide concentration range of $1.0{\times}10^{-5}-1.0{\times}10^{-1}$ M with super nernstian slope of 28.0 mV/decade and the detection limit of $8.0{\times}10^{-6}$ M. The proposed ion selective electrode showed fast response time (< 15 s), wide pH range (3.0-7.0), high non-aqueous tolerance (up to 20%) and adequate long life time (120 days). It also exhibited very good selectivity for $Fe^{3+}$ relative to a wide variety of alkali, alkaline earth, transition and heavy metal ions. Further, the analytical applicability of the sensor was tested as an indicator electrode in the potentiometric titration of $Fe^{3+}$ with EDTA.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1601-1608
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• 2010

A scandium(III) porphyrin-based fluoride-selective potentiometric sensor and its application in the analysis of hydrofluoric acid is described. Scandium(III) octaethylporphyrin, an ionophore recently developed for the optical fluoride sensor, was employed as a host molecule for the selective binding with fluoride in the plasticized PVC membrane. Nernstian response for $F^-$ between $10^{-4.6}$ to $10^{-1}$ M was observed at a glycine-phosphate buffer (pH 3.0). The selectivity pattern was observed as $F^-$, salicylate $\gg$ $SCN^-$ > $Cl^-$, $Br^-$, $NO_3{^-}$, $ClO_4{^-}$, which is consistent with the binding constant data measured in the plasticized PVC membrane based on a sandwich membrane method. This highly selective and reversible fluoride-sensitive electrode was employed for the analysis of hydrofluoric acid (HF). A disposable differential-type HF sensor was fabricated on the screen-printed electrode and demonstrated its ability to detect the neutral HF in the acidic solution.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.138-142
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• 2000

In LNG Tank, it is very important to measure the strain in Membrane by theoretical and experimental stress analysis. In this paper, perform the test about strain gage, thermal sensor and lead wire to make clear the properies. The test results conclude that stress measurement by strain gage must consider the effect of many factors to measure strain acculately. The corrections should be made on apparent strain, lead wire length and Membrane shape. It is also important to measure the temperatures accurately at the strain gage location

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1422-1424
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• 1994

This paper deals with piezoresistive humidity sensor using polycrystalline silicon (Poly-Si ) with membrane in sensors of semiconductor. Poly-Si piezoresistors which have no temperature dependancy are deposited on silicon wafer, membrane is formed with micromachining technology, then polyimide is formed as a hygroscopic layer. Whereas the principle of conventional humidify sensors are based on the change in electrical properties of the material, the humidity induced volume change of a polyimide layer leads to a deformation of a silicon membrane in this case. This deformation is transformed into an output voltage by Poly-Si piezoresistive. Wheatstone bridge. Fabricated piezoresistive humidity sensors showed good linearity, response time, and long term stability.

• KSBB Journal
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• v.17 no.1
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• pp.59-62
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• 2002

The enzyme sensor for ATPase activity consisted of an immobilized membrane of two enzymes, purine nucloside phosphorylase (NP) and xanthine oxidase (XOD), and oxygen electrode. The $H^ +-ATPase $ rate of the plasma membranes increased by low root temperature. A cucumber and a pumpkin plasma membrane $H^ +-ATPase $$ activities measured by the proposed sensor system were in good agreement with the results obtained by a conventional UV spetrometer assay. One cycle of assay could be completed within 3 minutes.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2482-2487
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• 2007

Numerical simulations are conducted for the analysis of a thermal mass air flow sensor with periodic heating pulses on silicon-nitride ($Si_3N_4$) thin membrane structure. This study aims to find the locations of temperature sensors on the thin membrane and the heating pulse conditions, that the higher sensitivity can be achieved, for the development of a MEMS fabricated mass air flow sensor which is driven in periodic heating pulse. The simulations, thus, focus on the membrane temperature profile according to variation of the flow velocity, heating duration time and imposed power. The flow velocity of the simulations is ranging from 3 m/s to 35 m/s, heating duration time from 1 ms to 3 ms and imposed power from 50 mW to 90 mW. The corresponding Reynolds numbers vary from 1000 to 10000.

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.172-176
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• 2004

A highly selective membrane electrode based on1,3,5-triphenylpyrylium perchlorate (TPPP) is presented. The proposed electrode shows very good selectivity for sulfate ions over a wide variety of common inorganic and organic anions. The sensor displays a nice Nernstian slope of -29.7 mV per decade. The working concentration ranges of the electrode is 1.0{\times}10^{-1}-6.3{\times}10^{-6} $M with a detection limit of $4.0{\times}10^{-6}$ M (480 ng per mL). The response time of the sensor in whole concentration ranges is very short (< 6 s). The response of the sensor is independent on the pH range of 2.5-9.5. The best performance was obtained with a membrane composition of 32% PVC, 59% benzyl acetate, 5% TPPP and 4% hexadecyltrimethylammonium bromide. It was successfully used as an indicator electrode for titration of sulfate ions with barium ions. The electrode was also applied for determination of salbutamol sulfate and paramomycine sulfate.

• Journal of Sensor Science and Technology
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• v.21 no.4
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• pp.283-286
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• 2012

This paper presents the optical hydrogen sensor based on transparent 3C-SiC membrane and photovoltaic effect. Gasochromic materials of Pd and Pd/$WO_3$ were deposited by sputter on 3C-SiC membrane for gas sensing area. Gasochromic materials change to transparency by exposure to hydrogen. The variations of light intensity by hydrogen generate the photovoltaic of P-N junction between N-type 3C-SiC and P-type Si. Single layer of Pd shows higher photovoltaic compared with Pd/$WO_3$. However, phase transition from ${\alpha}$ to ${\beta}$ is shown at 6 %. Pd/$WO_3$ structure show the more linear response to hydrogen range of 2 % ~10 %. Also, almost 2 times fast response and recovery characteristics are shown at Pd/$WO_3$. These fast performances are come from the fact that Pd promoted the chemical reaction between hydrogen and $WO_3$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.1
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• pp.33-36
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• 2012

In this study, the thickness effects of $Al_2O_3$ layer on the sensing properties of $SiO_2/Al_2O_3$ (OA) stacked membrane were investigated using electrolyte-insulator-semiconductor (EIS) structure for high quality pH sensor. The $Al_2O_3$ layers with a respective thickness of 5 nm, 15 nm, 23 nm, 50 nm, and 100 nm were deposited on the 5-nm-thick $SiO_2$ layers. The electrical characteristics and sensing properties of each OA membranes were investigated using metal-insulator-semiconductor (MIS) and EIS devices, respectively. As a result, the OA stacked membrane with 23-nm-thick $Al_2O_3$ layer shows the excellent characteristics as a sensing membrane of EIS sensor, which can enhance the signal to noise ratio.

• Journal of Sensor Science and Technology
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• v.18 no.5
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• pp.349-352
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• 2009

This paper describes the fabrication and characteristics of micro heaters built on AlN($0.1{\mu}m$)/3C-SiC($1{\mu}m$) suspended membranes by surface micromachining technology. In this work, 3C-SiC and AlN films are used for high temperature environments. Pt thin film was used as micro heaters and temperature sensor materials. The resistance of temperature sensor and the power consumption of micro heaters were measured and calculated. The heater is designed for operating temperature up to about $800^{\circ}C$ and can be operated at about $500^{\circ}C$ with a power of 312 mW. The thermal coefficient of the resistance(TCR) of fabricated Pt resistance of temperature detector(RTD)'s is 3174.64 ppm/$^{\circ}C$. A thermal distribution measured by IR thermovision is uniform on the membrane surface.