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This work reports the impedance analysis and carbon monoxide gas sensing response of tungsten oxide (WO3) nanofibers with silver (Ag) nanoparticle doping. The Ag-doped WO3 nanofibers were prepared by an electrospinning technique. The impedance spectroscopic measurements of undoped and Ag-doped WO3 nanofibers were performed to study the contribution of electrical parameters involved in the electron transport. The impedance modeling obtained from the fitted Nyquist plot shows that the RC components attributed to Ag-WO3 interface are introduced to the system upon Ag addition. Carbon monoxide (CO) gas detection was carried out by resistance measurement using a DC method. The sensitivity of Ag-doped WO3 nanofibers is found to be greater than that of the undoped sample. The improved sensitivity is derived from the high interface resistance between Ag and WO3 grains. The contribution of Ag dopants is conceived to induce electronic structure alteration of the sensor material.

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A means of improving edge-placement accuracy and waveform quality in high-speed high-performance integrated circuit test and verification systems is being developed. Its aim is to minimize timing skew, maintain signal integrity at the device under test (DUT), and actively reduce waveform errors caused by uncertain DUT loading and transmission path imperfections. The path between the pin electronic card (PEC) and the DUT is modeled using a signal flow graph (SFG) technique. The model contains both lumped and distributed circuit elements, each of which is represented by scattering parameters. Frequency-domain reflectometry (FDR) is used to measure voltage reflection coefficients of both the load (DUT) and PEC receiver ends of the transmission path. Load models are obtained through a direct search optimization algorithm. Examples of time domain compensation are presented for matched and mismatched transmission paths.