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The detection of H2 concentrations in concentrations undetectable by the conventional detection method of surface acoustic wave (SAW) sensors based on frequency shift, by…
The detection of H2 concentrations in concentrations undetectable by the conventional detection method of surface acoustic wave (SAW) sensors based on frequency shift, by correlating analyte presence with Fourier spectra components.
Fast Fourier Transform (FFT) and autocorrelation analysis of phase noise in a SnO2-coated SAW sensor was performed. Fourier spectra were obtained by FFT from the SAW sensor resonance frequency instability, in the absence of analyte, and for H2 concentrations between 0.08 and 0.4 per cent.
All analyte concentrations are below the sensor limit of detection, which is 0.8 per cent for H2. Although these analyte concentrations caused no significant change in the resonance frequency of the SAW resonator, the FFT spectra presented several modifications, namely, the appearance of a new peak and the decrease of randomness. The authors consider that the effect is because of the chaotic behavior of the temporal dependence of the SAW resonance frequency. This explanation is substantiated by the decrease observed in the SAW oscillator autocorrelation function, which is an indication for a chaotic behavior.
As chaotic systems are extremely sensitive to perturbation, measurement methods based on chaos diagnosis could potentially greatly improve the SAW detection.
Fourier spectra components were correlated with analyte presence in concentrations undetectable by the conventional SAW detection method based on frequency shift.
This study examines whether a unique set of emotions may be generated by advertisements for apparel products and brands for a young female target audience. Also studied…
This study examines whether a unique set of emotions may be generated by advertisements for apparel products and brands for a young female target audience. Also studied were the effects of emotions on evaluative perceptions of apparel brand advertisements (ad attitude). Test advertisements consisted of 90 advertisements representing 56 different brands. Using an aggregate‐level communication model, all analysis in the study was performed across advertisements, not across people, as sampling units of interest. Findings show a unique set of three emotional dimensions generated by the apparel brand advertisements. Two emotional dimensions, pleasure/activation (eg activation, bored, desired, social affection) and hypoactivation (drowsy, restful, soothed), had a positive influence on ad attitude. The third dimension, domination (anger, fear, irritation, tension), did not have a significant effect on ad attitude, having neither good nor bad effect on evaluations of advertisements.