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Drift compensation is an important issue for electronic nose systems. Traditional methods are costly and laborious because they need to frequently recalibrate referred gases or continually provide data labeling. In this paper, a new drift compensation method is proposed. The inspiration of our method is originated from semi-supervised domain adaption that can effectively tackle the mismatches between source domain and target domain. In our approach, a weighted geodesic flow kernel is initially constructed, then the combination of such kind of kernels is proposed considering that there are intermediate unlabeled data between the source and target domains. We will discuss how unlabeled data is selected from the target domain. The selected unlabeled data is used to provide incremental knowledge in order to dynamically adapt classifier to the target domain. Based on the kernel combination and selected unlabeled data, manifold regularization is used to train the classifier. To the best of our knowledge, we are the first to apply domain adaption to deal with the sensor drift problem. The advantages of our method include degrading recalibration rate, requiring few labeled data, and the robustness in handling the drift. Our experiments show that the proposed method significantly outperforms the baseline methods. [ABSTRACT FROM PUBLISHER]

Poly-(bistriethylphosphine)-platinum-diethynylbenzene (Pt-DEB) was synthesized by dehydrohalogenation reaction. X-ray photoelectron spectroscopy (XPS), FTIR, and 1H-NMR spectra were used to identify the formation of Pt-DEB target material. Sensitive properties of Pt-DEB-based quartz crystal microbalance (QCM) sensor to various organic vapors such as trichloromethane, tetrahydrofuran, acetone, isopropyl alcohol, ethanol, and methanol have been studied. The results show that Pt-DEB has good reversibility, reproducibility, and linear sensitivity to organic vapors at room temperature. The sensitivity of Pt-DEB (dissolved in CHCl3) toward CHCl3 is clearly higher than that toward other analytes, and a larger molecular weight of alcohol has a higher sensitivity response. The Pt-DEB-based QCM gas sensor shows low detection limits ranging from 1.0 to 3.56 ppm for the organic vapors and stable performance during a period of 30 days. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [ABSTRACT FROM AUTHOR]

A new material-poly{methyl [3-(2-hydroxyl, 4,6-bistrifluoromethyl)phenyl]propylsiloxane} (PMTFMPS), which was sensitive to toxic organophosphate vapor, was synthesized via O-alkylation, claisen rearrange reaction and hydrosilylation reaction. The polymer was coated on quartz crystal microbalance (QCM) to investigate its gas sensitive properties to nerve agents’ simulant dimethyl methylphosphonate (DMMP) vapor, as well as other interfering vapors. It was found that QCM sensor responded linearly to DMMP vapor with a slope of 27 Hz/ppm in the 10–50 ppm range. The material was much more sensitive to DMMP than to other interfering vapors, thus high selectivity to DMMP was demonstrated. The influence of humidity on the sensor response was also examined. The results showed that the frequency shifts were about 60% when tested in 77% RH wet air than in dry N2. When compared with our previously studied unfluorinated phenol-modified siloxane PMPS, PMTFMPS exhibited sensitivity enhancement of 2.3 times and an increased resistance to humidity variations. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF) was deposited onto a quartz crystal microbalance (QCM), using a standard Langmuir–Blodgett (LB) thin film deposition procedure. QCM technique was used to monitor the reproducibility of the LB film monolayer, and the fabricated QCM sensor was employed to detect the dimethyl methyl phosphonate (DMMP) vapor, a simulant of nerve agents. The results show that PVDF was successfully deposited from the water surface onto the quartz crystal substrate. The PVDF LB film is found to be highly sensitive to DMMP vapor, and frequency shifts are linear to the concentrations. The response of the sensor against DMMP is fast, large, and reversible. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [ABSTRACT FROM AUTHOR]

We have developed a free-standing-mode based triboelectric nanogenerator (F-TENG) that consists of indium tin oxide (ITO) foils and a polytetrafluoroethylene (PTFE) thin film. By utilizing the wind-induced resonance vibration of a PTFE film between two ITO electrodes, the F-TENG delivers an open-circuit voltage up to 37 V and a short-circuit current of 6.2 μA, which can be used as a sustainable power source to simultaneously and continuously light up tens of light emitting diodes (LEDs) and charge capacitors. Moreover, uniform division of the electrode into several parallel units efficiently suppresses the inner counteracting effect of undulating film and leads to an enhancement of output current by 95%. The F-TENG holds prominent durability and an excellent linear relationship between output current and flow rate, revealing its feasibility as a self-powered sensor for detecting wind speed. This work demonstrates potential applications of the triboelectric generator in gas flow harvesters, self-powered air navigation, self-powered gas sensors and wind vector sensors. [ABSTRACT FROM AUTHOR]