• Journal of Sensor Science and Technology
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• v.6 no.2
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• pp.131-136
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• 1997

The ISFET(ion sensitive field effect transistor), a semiconductor ion sensor, has many advantages over conventional ion sensors. Various single-sensor type ISFET pH-meters have been developed. However, they could not be applied in fields because their performances are directly affected by the sensor condition. With only one sensor, the system could be easily damaged from environmental factors, and reliability of it is decreased. Therefore, a 4-channel PH-meter system is proposed to improve the reliability of ISFET pH-meter. It has 4 ISFETS as ion sensor, and a software which contains a new calibration and measurement algorithm appropriate to the system. The reliability of the system was proved by measuring hydrogen ion concentration in the pH standard solutions and buffer solutions.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.143-152
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• 2014

In this study, the sensor response and sensitivity is experimented and analyzed quantitatively by the line numbers of chlorine ion reaction type corrosion sensor that is developed. The sensor response of the developed corrosion sensor is verified with properties of chlorine ion. The multilineal sensor is shown a large resistance change more than the single line sensor by damage of the sensor. And, the resistance change of sensor is as large as high concentration of NaCl aqueous solution, the sensitivity of multilineal sensor is higher than single line sensor's, and the depth of sensor's location is as large as the increasing of resistance change time (cycle). These results suggest that, the developed corrosion sensor could sense corrosion reaction, sensor sensitivity and change of resistance for chloride ion. Especially, It was judged that 7 line sensor was the most superior for monitoring chloride ion immigration into concrete.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.348-353
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• 2007

A solid state ion sensor module has been developed and evaluated for hydroponic nutrients analysis. The sensor module consisted of five ion-selective electrodes (ISE) fabricated by screen-printing technology. The electrochemical responses of ion sensors for nitrate, ammonium, potassium, calcium, and pH were measured with specially designed 7-channel low voltage signal transducers. The analytical characteristics of the sensors were comparable with those of conventional ISE sensors. The solid state ion sensors exhibit linear relationships over five concentration decades. Detection limit of the sensors were $5.6{\times}10^{-5}{\sim}1.6{\times}10^{-7}M$ depends on ions. Performance test results showed that relative errors of measured ion concentrations were less than 5% for $NO_3{^-},\;K^+,\;Ca^{2+}$ ion, and pH. The concentration of $NO_3{^-},\;NH_4{^+},\;K^+,\;Ca^{2+}$, and pH ion in standard solution and nutrient solutions could be determined by direct potentiometric measurements without any conditioning before measurements.

• Rapid Communication in Photoscience
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• v.1 no.2
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• pp.31-33
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• 2012

The Fluorescent 7-aminodipyrido[3,2-a:2',3'-c]phenazine (7-amino-dppz, 1) is functionalized as an europium ion ($Eu^{3+}$) sensor, which showed the effective emission quenching when europium cation is chelated to the bpy site of 1 compound. The complexation ratio indicated that the 1 compound forms a 1 : 1 complex with $Eu^{3+}$.

• Bulletin of the Korean Chemical Society
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• v.24 no.1
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• pp.23-26
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• 2003

Titanium acetylacetonate was used in the construction of a PVC-based membrane electrode. This sensor shows very good selectivity for iodide ion over a wide variety of common inorganic and organic anions. It exhibits Nernstian behavior with a slope of 59.1 mV per decade. The working concentration ranges of the sensor are with a detection limit of $3.0\;{\times}\;10^{-6}\;M$. The response time of the sensor is very fast (<8 s), and can be used for at least twelve weeks in the pH range of 4.0-9.2. The best performance was obtained with a membrane composition of 30% PVC, 65% dibutylphthalate, 3% titanium acetylacetonate and 2% hexadecyltrimethylammonium bromide. The proposed sensor was successfully applied as an indicator electrode for titration of iodide with silver ion.

• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.421-427
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• 2010

Alizarin Red S modified screen printed carbon electrodes were developed for the electrochemical detection of aluminum ion. The electrodes developed use screen-printed carbon electrodes(SPCEs) coupled with chemical modification with an organic chelator, Alizarin Red S(ARS), for aluminum ion detection in aqueous solution. For sensor fabrication ARS was directly immobilized on the surface of SPCEs using PVA-SbQ(The poly(vinyl alcohol) bearing stryrylpyridinium groups). Aluminum concentrations were indirectly estimated by amperometric determination of the non-complexed ARS immobilized on the electrodes, after its complexation with aluminum. The sensitivity of the sensor developed was $3.8\;nA{\mu}M^{-1}cm^{-2}$ and the detection limit for aluminum was $25\;{\mu}M$.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1562-1564
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• 2014

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.8
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• pp.1085-1091
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• 2014

A model based SOC estimation scheme using parameter identification is described and applied to a Lithium-ion battery module that can be installed in electric vehicles. Simulation studies are performed to verify the effect of sensor faults on the SOC estimation results for terminal voltage sensor and load current sensor. The sensor faults should be detected and isolated as soon as possible because the SOC estimation error due to any sensor fault seriously affects the overall performance of the BMS. A new fault detection and isolation(FDI) scheme by which the fault of terminal voltage sensor and load current sensor can be detected and isolated is proposed to improve the reliability of the BMS. The proposed FDI scheme utilizes the parameter estimation of an input-output model and two fuzzy predictors for residual generation; one for terminal voltage and the other for load current. Recently developed dual polarization(DP) model is taken to develope and evaluate the performance of the proposed FDI scheme. Simulation results show the practical feasibility of the proposed FDI scheme.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.4
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• pp.49-54
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• 2000

A new functional organic thin film optical waveguide ion sensor is designed, which can select a specific ion, i.e., $Ca^{2+}$ -ion. The sensing membrane was composed of PVC-PVAC-PVA copolymer matrix based on anionic cation-selective chromoionophor(ETH5294), neutral ionophore(K23El), anionic site and plasticizer and it was coated on the etched glass substrate as embeded type optical waveguide itself. The sensor sensitivity dependence on waveguide length and thickness, contence of chromoionophore, and each mode was investigated. And this sensor could detect $Ca^{2+}$ ion in concentrations ranging from 1$\times$10­6~1M(with 0.05M tris-HCI buffer solution of pH7.4) by measuring the absorbance change at 514nm of light. Utilizing thin film membrane, the fast response time and high sensitivity are obtained. Also, it is expected that this sensor can be applied to various biochemical important ions.ons.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1465-1470
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• 2004

A short and efficient synthesis, solvent extraction and potentiometric measurements of new thiazole-containing naphtho-crown ethers are reported. The naphthalene moiety enhances the ammonium ion selectivity over potassium ion. The selectivity of ${NH_4}^+/K^+$ follows the trend $3\;{\approx}\;2\;>\;1$, indicating that the differences in conformational changes of 2 and 3 in forming ammonium complexes affect little on the resulting ammonium/potassium extraction selectivity ratio. The ammonium ion-selective electrodes were prepared with noctylphenyl ether plasticized poly(vinyl chloride) membranes containing 1-4 the effect of one naphthalene unit introduced on either right (2) or left (3) side of thiazolo-crown ether on their potentiometric properties (e.g., ammonium ion selectivity over other cations, response slopes, and detection limits) were not apparent. However, the ammonium ion selectivity of 1, 2 and 3 over other alkali metal and alkaline earth metal cations is 10-100 times higher than that of nonactin.