• Journal of Sensor Science and Technology
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• v.3 no.2
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• pp.40-49
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• 1994

Potentiometric cell oxygen sensors using $CaF_{2}$ were fabricated for monitering the oxygen partial pressure in the low temperature range ($300^{\circ}C{\sim}$500^{\circ}C). The disk type oxygen sensors consist of a reference electrode: Air($O_{2}:21%$)|Pt, a solid electrolyte $CaF_{2}$, and a sensing metel Pt electrode. And the change in open circuit emf of the disk type cell was about 45mV for the oxygen concentration range, $0.1%{\sim}10%$, at the cell temperature of $400^{\circ}C$. Also, the reference electrode incorporated type sensor showed the change of 40mV for 0.1% to 10% oxygen partial pressure range.

• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.47-54
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• 1996

Highly sensitive $WO_{3}$ doped with $SnO_{2}$ and Pt thick-film sensors for NOx gas were fabricated. The sensors had a maximum sensitivity at operating temperature of $250^{\circ}C$, but the optimum operation temperature, considering recovery desorption time, was at $330^{\circ}C$. These sensors improved sensitivity, response and recovery time, selectivity and stability, as compared to $WO_{3}$ sensors. The good linearity of sensitivity as a function of the gas concentration exhibited the possibility to be used for concentration meter.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2544-2546
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• 1998

The electrical and physical charateristics of Pt-Co alloy thin films on $Al_2O_3$ substrate, deposited by r.f cosputtering respectively, were analyzed with thickness of thin films ($1700{\sim}10000{\AA}$) and increasing annealing temperature ($800{\sim}1000^{\circ}C$). At input power of Pt : 4.4 W/$cm^2$, Co : 6.91 W/$cm^2$, working vacuum of 10 mTorr and annealing conditions of $1000^{\circ}C$) and 60 min, the resistivity and sheet resistivity of Pt-Co thin films with thickness of $3000{\AA}$ was $15{\mu}{\Omega}{\cdot}cm$ and 0.5 ${\Omega}/{\square}$, respectively. The TCR value of Pt-Co alloy thin films was measured with various thickness of thin films and annealing conditions. The optimum TCR value of 3850 ppm/$^{\circ}C$ in temperature range($200{\sim}400^{\circ}C$) is gained under conditions $3000{\AA}$ of thin films thickness and $1000^{\circ}C$ of annealing temperature. The thermal charateristics of Pt-Co micro heaters were analysed with Pt-Co RTD integrated on the same substrate. In the analysis of characteristics of Pt-Co micro heaters, the Pt-Co micro heaters with thickness of $3000{\AA}$ and annealing temperature of $1000^{\circ}C$ had a good linearity and temperature is up to $468.2^{\circ}C$ with 2.1 watts of the heating power.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.3
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• pp.101-107
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• 1990

In this work, one-dimensional simulation is carried out for PT-GaAs Schottky barrier diodes with finite difference method. Shockley's semiconductor governing equations: Poisson equation and current continuity equation are discertized, and linearized by Newton-Raphson method. The linear system of equation is solved by Gaussian elimination method until convergence is achieved. The boundary condition for this equation is taken from thermionic emission-diffusion theory. Simulation is done for PT-GaAs epitaxial-layer Schottky barrier diodes. The claculated results of electron and potential distribution are shown. Simulation results show exellent agreement with experiments.

• Information and Communications Magazine
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• v.23 no.11
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• pp.26-39
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• 2006

• Journal of Sensor Science and Technology
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• v.6 no.3
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• pp.221-227
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• 1997

The Pd/NiCr gate MISFET-type sensors were fabricated for detecting hydrogen dissolved in high-capacivity transformer oil. To improve stability and high concentration sensitivity of the sensor, Pd/NiCr double catalysis metal gate was used. To reduce the serious gate voltage drift of the sensor induced by hydrogen, the gate insulators of 2 FETs were constructed with double layer of silicon dioxide and silicon nitride. The hydrogen sensitivity of the Pd/NiCr gate MISFET is about a half of Pd/Pt gate MISFET's sensitivity but the Pd/NiCr gate MISFET has good stability and high concentration detectivity up to 1000 ppm.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.83-89
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• 2001

This study was conducted to test the Cd accumulation and Cd-tolerance of Pisotithus tinctorius(Pt). Pt was isolated from Pinus thunbergii forest in Muan, Chonnam Province in 1997. Pt was cultured on MMN medium supplemented with $CdSO_4{\cdot}5H_2O$ at the final concentration of 0, 0.2, 0.5, 2, and $10{\mu}g/m{\ell}$ for 40 days. Growth rate and tolerance index of the fungus were measured every week, while Cd concentration, superoxide dismutase(SOD), and glutathione reductase(GR) of the fungus were analyzed at the end of the culturing, Pt showed growth reduction in vitro at $2{\mu}g/m{\ell}$ Cd in the medium and almost stopped growth at $10{\mu}g/m{\ell}$ Cd. Tolerance index of Pt decreased with increasing Cd concentration. Cd concentration of Pt was the highest at $10{\mu}g/m{\ell}$ Cd. Activities of SOD did not show significant difference between Cd concentrations, but GR of Pt increased at $0.5{\mu}g/m{\ell}$ Cd, and decreased at $2{\mu}g/m{\ell}$ Cd. Consequently Pt could be called Cd accumulator with a tolerance mechanism to Cd. Their tolerance to Cd were expressed through the higher production of antioxidants such as GR. Pt may be used for revegetation and decontamination of soil polluted by heavy metals.

• Journal of Sensor Science and Technology
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• v.8 no.4
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• pp.327-332
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• 1999

Catalytic combustion type gas sensors were fabricated by using noble metal(Pt and Pd) added ${\gamma}-Al_2O_3$ powder with specific surface area of $200\;m^2/g$. The fabricated sensor showed power consumption of 500 mW at the operating voltage of 1.75 V and high sensitivity of about 120 mV for butane, methane, or propane 100%LEL, respectively. The sensor properties also showed good linearity to hydrocarbon gas concentration variation, reproductivity and stability for relative humidity variation. And it showed high stability in butane ambient for 100 days.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1720-1722
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• 1999

In this paper, we studied the properties of small-size disk-type ultrasonic motor using travelling wave for the application to the precise control robotic joint motor and fabricated it. The diameter of the ultrasonic motor fabricated was 13mm. Also, the piezoelectric vibrator was constructed by piezoelectric ceramic and elastic material. The piezoelectric ceramic was composed to PZ-PT-PMN which was shown the high electromechanical stability under high vibration level and stainless steel was used as the elastic material in which configuration was disk-type. To conform the capability of application to robotic motor, we measured the change of rotational speed according to applied voltage and applied frequency. As the results, the small-size disk-type ultrasonic motor was able to fabricate, and the revolution speed was 350 [rpm] when input voltage was 55 [Vrms] and applied frequency 160.4 [kHz] under pre-load.

• Journal of Korean Society of Forest Science
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• v.83 no.4
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• pp.531-539
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• 1994

We examined the in vitro rooting and survival of tissue cultured plantlets of Quercus acutissima Carr. and Pinus densiflora Sieb. et Zucc. after addition of Pisolithus tinctorius(Pt) ectomycorrhizal fungus inoculum to the medium and effects of three levels of sucrose and phosphorus in culture media. Shoots of Quercus acutissima were obtained from winter buds of a 30-year old tree and cuttings of Pinus densiflora from germinated seed, and they were inoculated with Pt in vitro. In both species, Pt enhanced shoot length, survival, number of adventitious roots, root length, and rooting percentage. Survival in Quercus acutissima was increased from 75% in control to 100% in Pt inoculation. Pt inoculation increased the percentage of rooting from 20% to 70% in Quercus acutissima cuttings and from 63% to 100% in Pinus densiflora cuttings. It is concluded that mycorrhizal inoculation to tissue cultured Quercus acutissima Carr. and to in vitro cutting of Pinus densiflora Sieb. et Zucc. has practical application to improvement of poor root development and initial period of reduced shoot growth in vitro.