• 센서학회지
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• 제15권3호
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• pp.205-210
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• 2006

Hydrophobic polymer [ex. Poly(vinylidenfluoride)] layer was coated on polyaniline (PANi) sensor to reduce the contamination humidity. The differences in sensitivity to methanol gas detection in various humidity condition between pure-PANi sensor and sensor coated with poly(vinylidenfluoride) polymer (PVDF) (coated-PANi sensor) were investigated. Considering the relation between the density of pore, which was coated on the layer of the PANi sensor, and sensitivity was investigated. To fabricate the porous PVDF layer on PANi sensor, poly(vinylalcohol) (PVA), which is water-soluble polymer, was used. Coated-PANi sensor was less affected by humidity compared with pure-PANi sensor. And higher density of pore on PVDF layer led to higher sensitivity.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.428-430
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• 2008

Dye-sensitized solar cell has many internal resistant components such as Pt counter electrode, $TiO_2$/dye/electrolyte, charge diffusion, sheet resistance of TCO. Among these, the resistance about the counter electrode can be reduced by increasing the roughness factor of Pt counter electrode. This causes the increase of fill factor and improvement of efficiency. And the amount of light reflection on the counter electrode also increases as the roughness factor goes up. In our experiment, we suggest a new deposition structure of Pt thin film that is a stepped-type structure. The more step lines are in the counter electrode, the more roughness factor is. As a result, we get the improvement of fill factor and efficiency by controlling the roughness factor of counter electrode.

• 한국정밀공학회지
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• 제20권1호
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• pp.187-195
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• 2003

The performance of shock absorber is directly related to the car behaviour and performance, both for handling and ride comfort. The displacement sensitive shock absorber has two modes of damping force (i.e. soft and hard) according to the position of piston. In this study, a mathematical nonlinear dynamic model is introduced to predict the performance of displacement sensitive shock absorber. Especially in this paper, the transient zone is considered and the simulation result is well fit with experimental data. And the vehicle dynamic characteristic of displacement sensitive shock absorber is presented using quarter car simulation model. The simulation results of frequency response are compared with passive shock absorber.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1455-1458
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• 1997

In order to promote CO gas sensitivity, $SnO_2$ added ZnO prepared. The electrical conductivities and dielectric constants decreased by increasing $SnO_2$ content in air. The electrical conductivities in 1000ppm CO atmosphere were larger than in dry air. The measured CO sensitivities were $1{\sim}15.2$ at $100^{\circ}C{\sim}480^{\circ}C$. The maximum CO sensitivity of 15mol% $SnO_2$ added ZnO was 15.2 at $305^{\circ}C$.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.167-176
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• 2003

This study is focused on the development of a new muffler. A control valve installed in the exhaust system is operated by torsion springs, and its open angle is controlled automatically corresponding to the engine operating conditions. A control valve and a control muffler sensing exhaust-gas pressure are made f3r developing a new muffler. The experiments were done using an exhaust system simulator having the same pulsation wave frequency and similar pulsation propagation characteristics of a real exhaust system. The purpose of this study is to develope a new muffler system which has improved noise reduction quality and less power loss than conventional mufflers and electronic-control mufflers. Finally the characteristic of noise compared with conventional muffler and muffler sensing exhuast-gas pressure.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.103-106
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• 1997

The electrical properties and the sensing properties of ZnO-TiO$_2$ composites were investigated by using the complex impedance measurement and voltage-current source and measurement unit. In air, the electrical conductivity of TiO$_2$ added ZnO increase with increasing the content of TiO$_2$ and the relative dielectric constants for 3, 5 and 7mol% TiO$_2$ added ZnO are 7, 13 and 120, respectively. In 3000ppm CO gas, the relative dielectric constants for 3, 5mol% TiO$_2$ added ZnO are 25, 28, respectively.

• 한국전기전자재료학회논문지
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• 제11권6호
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• pp.453-457
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• 1998

In order to improve CO gas sensitivity, $TiO_2$added $SnO_2$ composite ceramics were prepared. Using XRD and SEM, the phases and micro structures of these ceramics were investigated. The resistances as a function of gas atmosphere were measured by High Voltage Measure/Source Unit. The maximum 100 ppm CO gas sensitivities of $SnO_2-TiO_2$composites were 2.5 times larger than that of pure $SnO_2$ composite and showed the obvious temperature dependence of sensitivities in 500, 100 ppm CO gas atmospheres.

• E2M - 전기 전자와 첨단 소재
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• 제9권8호
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• pp.819-824
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• 1996

We have investigated the temperature dependence of CO gas sensitivity for ZnO and ZnO-CuO thick films at 200 ppm CO gas, where those films were prepared by thermal transformation. The ZnO thick film shows the maximum sensitivity of -4 at >$300^{\circ}C$ On the other hand, ZnO-CuO(more than 1mol%) thick film shows that the maximum sensitivity reduced to less than 1.5. The decrease in sensitivity of CO gas with increasing the CuO contents is due to the decrease of the oxygen absorption in thick films.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.85-90
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• 1997

In the stroke sensitive shock absorber, the oil path is formed along the internal cylinder surface to make the eli flow during piston's upper-lower reciprocation movement. With constraint to the conventional shock absorbers which show one dynamic characteristic curve, stroke sensitive shock absorber shows two kins of dynamic characteristic according to the stroke, In the study, analysis on the damping force generation process and dynamic behaviour characteristics of stroke sensitive shock absorber is performed, the valve characteristics being considered more precise information about design and damping performance analysis.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2000년도 추계학술발표회 논문집
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• pp.124-129
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• 2000