In order to optimize laser ablation performance of a micro-thruster with 1U dimensions, which employs a micro semiconductor laser, the impacts of pulse width and glycidyl azide polymer (GAP) thickness on thrust performance was researched. The results showed that with a GAP thickness of 200 μm, the single-pulse impulse (I) increased gradually with the increase in the laser pulse width from 50 to 800 μs, while the specific impulse (Isp), impulse coupling coefficient (Cm), and ablation efficiency (η) all reached optimal values with a 200 μs pulse width. It’s worth noting that the optimal pulse width is exactly the ignition delay time. Both Cm and η peaked with the pulse width of 200 μs, reaching 242.22 μN/W and 35.4%, respectively. With the increase in the GAP thickness, the I and the Cm increased gradually. The GAP of different thickness corresponded to different optimal laser pulse width. Under a certain laser pulse width, the optimal GAP thickness should be the most vertical thickness of the ablation pit, and the various propulsion performance parameters at this time were also optimal. With the current laser parameters, the optimal GAP thickness was approximately 150 μm, the Isp was approximately 322.22 s, and the η was approximately 34.94%.
Ultrafine one-dimensional WO3 nanorods (NRs) with diameters of 10–200 nm have been fabricated using a hydrothermal synthesis method. The optical performance of the WO3 NRs strongly depends on their various defects as well as their crystal quality. Upon exposure to trace quantities of ethanol gas, the photoluminescence (PL) spectra of these nanorod samples under ultraviolet illumination showed a large variation in intensity. WO3-NR-based ethanol gas sensing via PL spectra variation demonstrated a 100 ppm sensitivity detection limit and a wide linear detection range of 200–2000 ppm at 100°C. This outstanding optical ethanol sensing performance can be ascribed to the very large surface area to volume ratio of this material, which increases the density of active sites for ethanol adsorption and reaction with adsorbed oxygen species.
In the field of laser ablation micro-propulsion, the property of double-layer tape has significant impact on the propulsion performance. In this paper, low temperature plasma was used to treat the surface of polyethylene terephthalate (PET) to improve its adhesion with energetic polymer. The PET surface pre- and post-plasma treatment was characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), and the enhancement mechanism of the interface adhesion was discussed. In addition, the ablation performance of the double-layer tape after the plasma treatment was studied. The results showed that the plasma etching effect increased the root mean square roughness of the PET surface from 1.74 nm to 19.10 nm. In addition, after the plasma treatment, the number of C–OH/COOH bonds and O=C–O bonds increased, which also greatly improved the adhesion between the PET and energetic polymers. In the optimization of the ablation performance, the optimal laser pulse width was about 200 μs. The optimal values of the specific impulse (Isp), impulse coupling coefficient (Cm), and ablation efficiency (η) were 390.65 s, 250.82 μN/W, and 48.01%, respectively. The optimization of the adhesion of the double-layer tape and the ablation performance lay the foundation for the engineering application of laser ablation micro-thrusters.
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