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Improvement in Sensitivity and Recovery of Single-Walled Carbon Nanotube-Based Gas Sensors

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稀有金属材料与工程 2006年第A03期35卷 188-189页

作者： Hong-Quang Nguyen Geon-Young Cha Joon-Boo Yu jeung-soo huh Department of Materials Science and Metallurgy Kyungpook National UniversitySangyuk-DongBukgu 1370Daegu 702-701Korea

In this paper,an improvement in sensitivity and recovery of the single-walled carbon nanotube (SWNT)-based gas sensors was *** sensors were fabricated from SWNT powder by a screen-printing method,followed by annealing for 2 h in open-air at various *** Raman spectra of the SWNT bundles and the response to ammonia (NH_3) exposure of the sensors indicated that the annealing at a relevant temperature improved the sensor *** sensor annealed at 200℃exhibited a high sensitivity in NH_3 *** 20 min of exposure to NH_3 at room temperature,the resistance of the sensor increased up to 12% in comparison with its initial *** evacuating combined with maintaining the flux of carrier gas at 300 sccm,the sensor recovery was significantly *** sensor resistance retrieved to its initial value after only 25 min degassing. These results would be considered in the development of the SWNT-based gas sensors.

关键词： carbon nanotubes gas adsorption recovery sensitivity sensor

Recoverable SnO_2-Based Sensors Promoted with MoO_3 and Sb_2O_3 for the Detection of DMMP

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稀有金属材料与工程 2006年第A03期35卷 155-156页

作者： Woo Suk Lee Ho Yun Choi soo Chool Lee soo Jae Lee Duk Dong Lee jeung soo huh Jae Chang Kim Department of Chemical Engineering Kyungpook National UniversityDaegu 702-701Korea School of Electrical Engineering and Computer Science Kyungpook National UniversityDaegu 702-701Korea Department of Materials Science and Metallurgy Kyungpook National UniversityDaegu 702-701Korea

The sensitivity and the recovery behavior of SnO_2-based gas sensor prepared from a commercial SnO_2 powder were tested under the low concentration of DMMP(0.5μg/g) in the flow system at 350℃.In order to improve the sensitivity of the sensor,promoters such as NiO,Nb_2O_5,MoO_3,and Sb_2O_3 were added into SnO_2 *** sensitivities were increased up to 80% from 50% but they were not *** the SnO2-based gas sensor promoted with MoO_3 and Sb_2O_3 was recovered after detection of DMMP,although the recovery rate was *** particular,the SnO_2-based sensor promoted with 5wt% of MoO_3 and 1wt% of Sb_2O_3 simultaneously showed an complete recovery ability,though its sensitivity was 40% which was lower than that of SnO_2 gas sensor without *** ability was discussed in terms of catalytic roles of promoters.

关键词： SnO2 MoO3 Sb2O3 sensor,recovery DMMP

The Sensing Behavior to Volatile Organic Compounds Gas on Polypyrrole Sensor under Humidity Condition

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稀有金属材料与工程 2006年第A03期35卷 65-66页

作者： Jae-Hyun Cho Joon-Boo Yu Sung-Ok Sohn Duk-Dong Lee jeung-soo huh Department of Material Science Metallurgy Kyungpook National UniversitySangyuk-Dong 1370DaeguKorea School of Electronic Engineering Kyungpook National UniversitySangyuk-Dong 1370DaeguKorea

Polypyrrole (PPy) powder was synthesized by chemical polymerization at 0℃under atmospheric condition and its layer was prepared by dip coating method on the alumina substrate with interdigitated *** influence of relative humidity (RH 0～70%) to PPy sensor was *** measuring temperature was fixed at 25℃.Methanol and benzene were used as target *** analytic techniques were examined to observe changes in the properties of PPy *** sensitivity of PPy sensor to water vapor was linearly increased with the increasing *** the relative humidity increase from 0% to 70%,the sensitivities to methanol and benzene vapor were reduced,and reduction ratio of sensitivity was 94%, 92.5% at RH 70%,respectively.

关键词： VOCs polypyrrole humidity effect gas sensor

Synthesis and Gas Sensing of TiO_2 Ultrafine Powders by Precipitating

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稀有金属材料与工程 2006年第A03期35卷 163-164页

作者： Min-Hyun Seo Bong-Ho Lee Jong-Won Kim Gi-Hong Rue Duk-Dong Lee jeung-soo huh Department of Sensor and Display Engineering Kyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea Department of Materials Science and Metallurgy Kyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea Department of Nano-science and Technology Kyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea School of Electronic Engineering Kyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea Department of Sensor and Display Engineering Kyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea.Department of Nano-science and TechnologyKyungpook National UniversitySangyuk-DongBukguDaegu 1370Korea

We investigated the gas sensing characteristics of rutile and anatase TiO_2 nano-particle sensors for chemical warfare ***_2 nano-powders with rutile and anatase structure were fabricated by controlling pH value without heat treatment *** mean particle size of TiO_2 powders were below 10 ***-prepared TiO_2 powders have several advantages of nano particle size and high surface area and could be a prominent candidate for ***_2 sensors were examined with DMMP for chemical warfare agents detection.

关键词： TiO2 chemical warfare agents sensor nano-sensor pH

H_2S Sensing Characteristics of Thin Film SnO_2 Sensor with N_2 Treatment

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稀有金属材料与工程 2006年第A03期35卷 385-388页

作者： Jong-Won Kim Kwang-Hyun Yun Geon-Young Cha Gi-Hong Rue Duk-Dong Lee jeung-soo huh Department of Nano-Science and Technology Sangyuk-Dong 1370Bukgu DaeguKorea Department of Materials Science and Metallurgy Sangyuk-Dong 1370Bukgu DaeguKorea School of Electronic Engineering Kyungpook National UniversitySangyuk-Dong 1370Bukgu DaeguKorea Department of Nano-Science and Technology Department of Materials Science and MetallurgySangyuk-Dong 1370Bukgu DaeguKorea

SnO_2 thin film sensors were fabricated by a thermal evaporation *** sensors were heated for thermal *** high porosity,SnO_2 thin film sensors were treated in a N_2 *** sensors that were treated with O_2 after being treated with N_2 showed 70 % sensitivity for 1×10~ -6) of H_2S,which is higher than the sensors that were only treated with O_*** Ni metal,as a catalyst,was evaporated on the thin film Sn on the Al_2O_3 *** sensor was heated to grow the Sn nanowire in a tube furnace with N_2 *** nanowire was heated for *** sensitivity of SnO_2 nanowire sensor was measured for 500×10~ -9) of H_*** selectivity of the SnO_2 nanowire sensor was compared with the thin film and the thick film SnO_*** sensor was measured for H_2S,CO,and NH_3 in this study.

关键词： SnO2 gas sensor N2 nanowire H2S

Sensing Characteristics of Polyaniline Sensor Coated with Porous Poly(vinylidenfluoride) Layer to Methanol Gas

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稀有金属材料与工程 2006年第A03期35卷 459-462页

作者： Cheol-Beom Lim Joon-Boo Yu Do-Yeon Kim Sung-Ok Sohn Duk-Dong Lee jeung-soo huh Department of Sensor and Display Engineering Kyungpook National UniversitySangyuk-Dong 1370BukguDeaguKorea Department of Materials Science & Metallurgy Kyungpook National UniversitySangyuk-Dong 1370BukguDeaguKorea Department of Electronic Engineering Kyungpook National UniversitySangyuk-Dong 1370BukguDeaguKorea Department of Sensor and Display Engineering Kyungpook National UniversitySangyuk-Dong 1370BukguDeaguKorea.Department of Materials Science & MetallurgyKyungpook National UniversitySangyuk-Dong 1370BukguDeaguKorea

Hydrophobic polymer [***(vinylidenfluoride)] layer was coated on polyaniline (PANi) sensor to reduce the problems of *** differences in sensitivity to methanol gas detection in various humidity condition between pure-PANi sensor and coated with poly(vinylidenfluoride) polymer (PVDF) (coated-PANi sensor) were *** the relation between the density of pore,which was coated on the layer of the PANi sensor,and sensitivity was *** 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 *** higher density of pore on PVDF layer led to higher sensitivity.

关键词： polyaniline PVDF PVA methanol gas humidity

Improvements of model-test method for cavitation-induced pressure fluctuation in marine propeller

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Journal of Hydrodynamics 2013年第4期25卷 599-605页

作者： LEE jeung-Hoon HAN Jae-Moon PARK Hyung-Gil SEO Jong-soo Samsung Ship Model Basin (SSMB) Marine Research Institute Samsung Heavy Industries Science Town

Although the prediction of propeller cavitation-induced pressure fluctuation strongly depends on the model-scalemeasure- ment in a cavitation tunnel, there is still a lack of correlation with full-scale data. This paper deals with the enhancement of such a correlation deficiency by improving the conventional model-test technique, two majors of which are in the following. One is to take into account the boundary layer effect of wooden fairing plate at the ceiling of water cavitation tunnel. The other is to avoid the reso- nance frequency range of model-ship via adjusting the revolution speed of model propeller. Through a case study, for which both model and full-scale test data are available, the improved method in this study shows its validness, and furthermore a close correla- tion with full scale measurement.

关键词： cavitation boundary layer resonance

Application of signal processing techniques to the detection of tip vortex cavitation noise in marine propeller

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Journal of Hydrodynamics 2013年第3期25卷 440-449页

作者： LEE jeung-Hoon HAN Jae-Moon PARK Hyung-Gil SEO Jong-soo Samsung Ship Model Basin (SSMB) Marine Research Institute Samsung Heavy Industries Science TownDaejeon 305-380 Korea

The tip vortex cavitation and its relevant noise has been the subject of extensive researches up to now. In most cases of experimental approaches, the accurate and objective decision of cavitation inception is primary, which is the main topic of this paper. Although the conventional power spectrum is normally adopted as a signal processing tool for the analysis of cavitation noise, a faithful exploration cannot be made especially for the cavitation inception. Alternatively, the periodic occurrence of bursting noise induced from tip vortex cavitation gives a diagnostic proof that the repeating frequency of the bursting contents can be exploited as an indication of the inception. This study, hence, employed the Short-Time Fourier Transform （STFT） analysis and the Detection of Envelope Modulation On Noise （DEMON） specmma analysis, both which are appropriate for finding such a repeating frequency. Through the acoustical measurement in a water tunnel, the two signal processing techniques show a satisfactory result in detecting the inception of tip vortex cavitation.

关键词： tip vortex cavitation inception Short-Time Fourier Transform (STFT) Detection of Envelope Modulation On Noise(DEMON)

Characteristics of machined surface controlled by cutting tools and conditions in machining of brittle material

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中国有色金属学会会刊：英文版 2009年第B09期19卷 194-201页

作者： Yong-Woo KIM soo-Chang CHOI jeung-Woo PARK Deug-Woo LEE Department of Nano Fusion Technology Pusan National University Department of Mechanical Design Engineering Chosun University Department of Nanosystem and Nanoprocess Engineering Pusan National University

One of the ultra-precision machining methods was adapted for brittle material as well as soft material by using multi-arrayed diamond tips and high speed spindle. Conventional machining method is too hard to control surface roughness and surface texture against brittle material because the particles of grinding tools are irregular size and material can be fragile. Therefore, we were able to design tool paths and machine controlled pattern on surface by multi-arrayed diamond tips with uniform size made in MEMS fabrication and high speed spindle, and the maximum speed was about 3×105 r/min. We defined several parameters that can affect the machining surface. Those were multi-array of diamond tips (n×n), speed of air spindle and feeding rate. The surface roughness and surface texture can be controlled by those parameters for micro machining.

关键词：加工表面脆性材料条件控制刀具路径表面粗糙度特征高速主轴加工方法