The polyaniline/PdO composite was synthesized by chemical oxidative polymerization of aniline with PdO nanoparticles. A methane gas sensor was made by deposition polyaniline/PdO thin films on a mass-type quartz crystal microbalance (QCM) device through layer-by-layer (LbL) self-assembly method. Scanning electron microscopy inspection shows that the polyaniline/PdO multilayers are formed with a dense network of nanofibers. The frequency responses of the polyaniline/PdO based QCM sensor to methane gas were measured at room temperature and 50℃. It exhibited that the polyaniline/PdO based QCM gas sensor has a better response at room temperature than that at 50℃. Meanwhile, the humidity effect is also discussed.

Tungsten trioxide (WO3) thin films were prepared by vacuum thermal deposition and subsequently annealed in the temperature range of 300–600 ◦C. X-ray diffractometry (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to analyze the structure and the morphology of the fabricated thin films. The results showed that the average grain size changed considerably with the variation of annealing temperature. Using a pair of interdigitated Au electrodes and glass ceramics as a substrate, the humidity and NO2 sensing properties of the WO3 thin films, manifested in relative conductivity changes, were measured. The results showed that the humidity sensitivity of the WO3 thin films was strongly dependent on the annealing temperature, and annealing and working temperature played an important role in the NO2 sensing characteristics. 2006 Elsevier B. V. All rights reserved.

Based on conventional metal-oxide-semiconductor field-effect transistor (MOSFET), a novel kind of chemical field-effect transistor (ChemFET) gas sensor array has been designed and fabricated. The obtained sensor consists of self-assembly polyaniline (PAhD composite film containing poly (acrylic acid) (PAA) which was used as gate material of MOSFET instead of conventional metallic gate. The UV-Vis absorption spectra of PAN/PAA films were characterized. The N02 gas sensitive property of the ChemFET sensor array was also Based on conventional metal-oxide semiconductor field-effect transistor (MOSFET), a novel kind of chemical field-effect transistor (ChemFET) gas sensor array has been designed and fabricated. The obtained sensor consists of self-assembly polyaniline (PAhD composite film containing poly (acrylic acid) (PAA) which was used as gate material of MOSFET instead of conventional metallic gate. The UV-Vis absorption spectra of PAN/PAA films were characterized. The N02 gas sensitive property of the ChemFET sensor array was also investigated. Results show that the drain current of devices increases with increasing of back-side voltage, and decreases with the increase of N02 concentration when the N02 concentration is below 20mg/g. The temperature dependence of ChemFET sensor array shows that the drain current of ChemFET sensor decreases with increasing of temperature.

A readout circuit for uncooled infrared focal plane arrays is successfully designed. The principle of the signal processing is studied and proper circuit is successfully designed and made to realize the signal processing. The feature of the signal processing circuit for the uncooled infrared focal plane array depends on the readout circuit Readout circuit discussed here is a RC oscillatory circuit. The resistor of the oscillatory circuit is VOx thin film, which is very sensitive to temperature. The relationship of the temperature and the period of the oscillatory circuit is discussed. The signal processing circuit employs the relationship to extract the temperature from the period of the output signal. The imaging processing part uses the extracted temperature information to get the infrared image.

Multilayer PVDF-BaTiO3/PDDA ultrathin composite film was prepared in the presence of BaTiO3 nanoparticles by electrostatic self-assembly method, and quartz crystal microbalance was in situ used to monitor the whole film fabrication process. The results showed that the film with 1: 1 weight ratio of PVDF to BaTiO3 is more uniform than that of 2: 1 ratio. The monolayer film thickness ranges from 19 to 25nm calculated by Sauerbery equation. Coupling agent enhanced the dispersion capability of BaTiO3 nanoparticles, and the ferroelectric property of PVDF/PDDA composite ultrathin film was improved with the assistance of inorganic nanoparticles.