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Characteristics of suspended planar-type gas sensor based on MEMS process

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Journal of Southeast University(English Edition) 2012年第3期28卷 315-320页

作者：张子立殷晨波陶春旻朱斌南京工业大学机械与动力工程学院南京210009

In order to simplify the fabrication process,distribute the temperature uniformly and reduce the power consumption of the micro-hotplate（MHP） gas sensor,a planar-type gas sensor based on SnO2 thin film with suspended structure is designed through a MEMS ***-state thermal analysis of the gas sensor and the closed membrane type sensor where the membrane overlaps the Si substrate is carried out with the finite element model,and it is shown that the suspended planar-type gas sensor has a more homogeneous temperature distribution and a lower power *** the maximum temperature on the sensor reaches 383℃,the power consumption is only 7 mW,and the temperature gradient across the thin film is less than 14℃.To overcome the fragility of the suspended beams,a novel fabrication process in which the deposition of the gas sensing film occurs prior to the formation of suspended beams is *** back side of the Si substrate is etched through deep reactive ion etching（DRIE） to avoid chemical pollution of the front *** fabrication steps in which only four masks are used for the photolithography are described in *** Fe doped SnO2 thin film synthesized by sol-gel spin-coating is used as the gas sensing *** device is tested on hydrogen and exhibits satisfactory sensing *** sensitivity increases with the rise of the concentration from 50×10-6 to 2000×10-6,and reaches about 30 at 2000×10-6.

关键词： gas sensor suspended planar-type micro fabrication gas sensing characteristic

Amperometric Nitrous Oxide gas sensor： Preparation ol Cu/PANI/Cu Electrodes and Sensing Behavior

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Journal of Environmental Science and Engineering(B) 2012年第12期1卷 1297-1302页

作者： Luisa Quifiones-Montenegro Eduardo Herrera-Peraza Carmen Navarro B. Trujillo-Navarrete Yadira Gochi Laura Ortega Department of Environment and Energy Research Center for Advanced MaterialsMdxico Chihuahua 31000 Graduate Department Technological Institute of OaxacaMdxico Oaxaca 68000 Department of Basic Science Technological Institute of Chihuahua II. Chihuahua MexicoChihuahua 31000

The authors studied the changes in the electrical properties of PANI （polyaniline） when exposed to the presence of N20 （nitrous oxide）. The techniques used to determine the adsorption of gas in the polymer were the electrochemical impedance, steps voltammetry and transmission electron microscopy. The objective of this work was to determine the ability of adsorption and desorption of PANI to be used as sensor in an open environment. Measurements were performed in a controlled atmosphere, temperature and flux. The gas was passed through a glass capsule in which an electrochemical cell was designed with copper electrodes and PANI as electrolyte. The change in electrical properties of the material is analyzed using a potentiostat/galvanostat in situ. Subsequently, the material was analyzed by TEM （Transmission Electron Microscopy） elemental analysis. The measurements were performed with difl^rent concentrations of N20 with a purity of 99%. As a result of measurements, it was found that the change in electrical resistance of PANI is caused by the physical interaction that occurs when in contact with NzO and even a change in the morphology of polymer, however, the binding is weak and sufficient to increase the temperature at which 25% PANI film regains its original properties.

关键词： Polymer electrochemical gas sensor nitrous oxide impedance.

Improved gas sensor with air-core photonic bandgap fiber

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Frontiers of Optoelectronics 2015年第3期8卷 314-318页

作者： Saeed OLYAEE Hassan ARMAN Nano-Photonic and Optoelectronic Research Laboratory (NORLab) Faculty of Electrical and Computer Engineering Shahid Rajaee Teacher Training University Tehran 16788-15811 Iran

The propagation loss of a fiber can be increased by coupling core mode and surface mode which will deteriorate the performance of photonic bandgap fiber （PBGF）. In this paper, we presented an aircore PBGF for gas sensing applications. By designing A = 2.63 μm, d = 0.95 A, and Reore= 1.13 A, where A is the distance between the adjacent air holes, the fiber was single-mode, no surface mode was supported with fiber, and more than 90% of the optical power was confined in the core. Furthermore, with optimizing the fiber structural parameters, at wavelength of 2 = 1.55 μm that is in acetylene gas absorption line, significant relative sensitivity of 92.5%, and acceptable confinement loss of 0.09 dB/m, were simultaneously achieved.

关键词： gas sensor photonic bandgap fiber (PBGF) sensitivity surface modes air core radius confinement loss

Novel Optical Fiber gas sensor for On-line Measurement of Methane

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Semiconductor Photonics and Technology 2004年第2期10卷 141-144页

作者： WANGShu-tao CHERen-sheng LIUJin WANGYu-tian Dept.ofPrecis.Instrum.andMechan. HarbinInstituteofTechnologyHarbin150001CHN CollegeofElectr.Eng. YanshanUniversityQinhuangdao066004CHN

Based on analysis of near infrared spectral absorption of methane,absorption type optical fiber methane gas sensor with high sensitivity using DFB LD as a source is demonstrated. Light source modulation harmonic measurement is presented in this paper. In order to eliminate the noise, the ratio of the fundamental and second-harmonic signals is used. The mathematical model of gas concentration harmonic measurement is built *** detection result of methane concentration is also shown. Experiments have proved a sensitivity of 28×10-6.

关键词： gas sensor Methane Modulation Harmonic measurement

One-step solvothermal synthesis of indium oxide as liquefied petroleum gas sensor

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Journal of Shanghai University(English Edition) 2007年第4期11卷 407-410页

作者：徐甲强王晓华沈嘉年 College of Materials and Chemical Engineering Zhengzhou University of Light Industry Zhengzhou 450002 P. R. China Department of Chemistry College of SciencesShanghai University Shanghai 200444 P. R. China Institute of Materials Shanghai University Shanghai 200072 P. R. China

A liquefied petroleum gas （LPG） sensor with high selectivity, sensitivity and low power consumption has been developed based on indium oxide with very low resistance. Nanocrystalline In203 gas sensing materials were directly synthesized through a one-step controllable solvothermal process at 210 ℃ for 24 h, using InCI3.4H2O as the starting material, cetyltrimethyl ammonium bromide （CTAB） as additive and ethanol as the solvent. The obtained samples were characterized by X-ray diffraction （XRD）, and transmission electron microscopy （TEM）. The results showed that indium oxide takes on uniform cubic shape with range size of 10~30 nm and fine dispersivity. gas sensitivity was measured in a mixing static gas. The results indicated that 3.0 V is the best working voltage of the sensor to LPG. Sensitivity is 12.6. The response-time and recovery-time are 3 s and 10 s respectively. Power consumption is only around 200 mW.

关键词： solvothermal process In203 gas sensor low power consumption liquefied petroleum gas (LPG).

Novel gas sensor Based on Nano-zeolite Films for the Nerve agent simulant Dimethylmethylphosphonate detection

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Novel Gas Sensor Based on Nano-zeolite Films for the Nerve a...

2004 7th International Conference on Solid-State and Integrated Circuits Technology（ICSICT 2004）

作者： Haifen Xie~(a,b) Xiao Xiang Sun~a Qiudong Yang~a Jianye Wang~a Yiping Huang~(a*) aASIC and System State Key Lab,Department of Microelectronics,220 Handan Road,Shanghai,China,200433 bPhysics department of East China University of Science and Technolegy,Jinshan campuse 1000 Xuefu Road,Shanghai, China,201512

A novel gas sensor based on nanosized zeolite for the detection of nerve agent simulant gas Dimethylmethylphosphonate(DMMP)is developed in this *** ZSM-5 zeolite films and Ag modified ZSM-5 zeolites films as a novel sensing membrane materials are immobilized on the piezoelectric sensor device QCM(Quartz Crystal Microbalance).A frequency shift with different concentrations of DMMP is *** gas sensor based on nanosized zeolite in resonating mode,whose resonant frequency shifts due to mass loading,has shown high sensitivity for detecting *** minimum detection concentration of DMMP is 1ppm in the N at *** frequency shift is about 60H for lppm *** order to improve the selectivity of the sensor to the DMMP from other organic gases,different pore size zeolite films such as ZSM-5 zeolites and Ag modified ZSM-5 zeolites are studied. The frequency shifts to another two organic gases such as acetone and ethanol at lppm concentration are observed for the sensor selectivity *** relationship between frequency shift and temperature for lppm DMMP has been *** best adsorption temperature is 303K and the desorption temperature is at the DMMP boiling point,*** principle component analysis(PCA);we can easily qualify and quantify the DMMP gas.

关键词： Zeolite QCM DMMP gas sensor PCA

Preparation and Property of Lanthanum Ferrite Formaldehyde gas sensor Modified by Carbon Nano Tubes and Silver

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Preparation and Property of Lanthanum Ferrite Formaldehyde G...

2012 China Functional Materials Technology and Industry Forum

作者： Yu-min Zhang Yu-tao Lin Jin Zhang Zhong-qi Zhu Qiang Liu Qing-ju Liu Yunnan Key Laboratory of Nanomaterials & Nanotechnology Yunnan University

Our previous study revealed that the gas sensitive property of Silver-modified Lanthanum Ferrite(Ag-LaFeO) is well,but the operating temperature is still high and the sensitivity also needs to be *** work based on our previous ***-LaFeO was further modified by the Carbon Nano Tubes(CNTs).The Ag-LaFeO powder modified with CNTs(CNTs-Ag-LaFeO) was prepared by a sol-gel method combined with microwave chemical *** structure and gas-sensing properties were *** results show that the structure of CNTs-Ag-LaFeO is of orthogonal *** sensitivity of 0.75%CNTs -Ag-LaFeO powder for 1 ppm formaldehyde is 13 at 86℃.The response and recovery time are 100s and 60s,***,the sensor also has an obvious response for 1ppm formaldehyde at 58℃.

关键词： gas sensor LaFeO3 Carbon Nano Tubes

Optimization of Coal Mine gas sensor based on Simulation and underground Electromagnetic Measure

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Optimization of Coal Mine Gas Sensor based on Simulation and...

第24届中国控制与决策会议

作者： Ma Fengying College of Electrical Engineering and Automation, Shandong Polytechnic University, Jinan 250100, China

In order to prevent from giving false alarms of gas sensors, caused by Electromagnetic Interference （EMI）, a original method was presented in which the simulation and radiated emission measure were adopted to accomplish the analysis of immunity about gas sensor. The data was obtained with the R＆S spectrum analyzer FSP7 and the Agilent portable oscillograph. With analyzing the influence of alarm and apertures on enclosure shielding properties through simulation and measure, the optimization of explosion-proof enclosure was finished according to the distribution of radiated interference characteristics. After optimizing, the false alarms significantly reduced. However, there were still occasionally false alarms when nearby electrical equipments were turned on and off. Therefore the complex EMI filter was put forward at power ports and the EMI was controlled within the allowable range. The results proved that the problem of false alarms had been resolved successfully. It is concluded that the improved shielding and filtering are highly significant in enhancing the Electromagnetic Compatibility （EMC） of the gas sensor.

关键词： gas sensor false alarm electromagnetic measure simulation EMC

Thin-film-bulk-acoustic-resonator gas sensor for the detection of organophosphate vapor detection

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Thin-film-bulk-acoustic-resonator gas sensor for the detecti...

2011年全国压电和声波理论及器件应用研讨会

作者： Jing-jing WANG~1 Da CHEN~(2,*) 1 Jinan campus,Shandong University of Science and Technology,Jinan 250010 P R China 2 Qingdao Key Laboratory of Terahertz Technology.College of Science,Shandong University of Science and Technology,Qingdao 266510 P R China

＜正＞A novel design of an organophosphate vapor sensor based on a thin film bulk acoustic resonator（TFBAR） is *** TFBAR device is consisted of an AlN piezoelectric stack and a Bragg reflector of Mo/*** order to det... 详细信息

关键词： Thin film bulk acoustic resonator gas sensor Organophosphate vapor Poly(vinylidene fluoride)