Synthesis, Characterization, and Gas Sensing Applications of WO3 Nanobricks

Abstract

WO 3 nanobricks are fabricated by a simple hydrothermal method. Morphology and structure of the WO 3 nanobricks are characterized by scanning electron microscopy and x-ray diffraction. Gas sensing properties of the as-prepared WO 3 sensor are systematically investigated by a static gas sensing system. The results show that the WO 3 nanobricks with defect corners demonstrate good crystallinity, and the mean edge length and wall thickness are 1-1.5 and 400 nm, respectively. The WO 3 sensor achieves its maximum sensitivity to 100 ppm ethanol at the optimal operating temperature of 300°C. Ultra-fast response time (2-3 s) and fast recovery time (4-11 s) of the WO 3 sensor toward 100 ppm ethanol are also observed at this optimal operating temperature. Moreover, the WO 3 sensor exhibits high selectivity to other gases such as methanol, benzene, hexane, and dichloromethane, indicating its excellent potential application as a gas sensor for ethanol detection.

Device-Free Indoor Localization Based on Data Mining Classification Algorithms

“…Xiao and Song proposed a DFL method using outlier link rejection. (3) Owing to the uncertainty of a wireless channel, certain links may be seriously polluted, resulting in error detection. The authors first identified the outlier link and then rejected this link to reduce the error induced by it.…”

“…Researchers have proposed DFL systems using different technologies such as RF, (1)(2)(3) camera, (4) infrared, (5) and ultrasonic. (6) Radio frequency (RF)-based schemes have advantages of long range, low cost, and the ability to work through nonconducting walls and obstacles.…”