A novel integration of three-dimensional (3D) architectures of near-field electrospun polyvinylidene fluoride (PVDF) nano-micro fibers (NMFs) is applied to an intelligent self-powered sound-sensing element (ISSE). Using 3D architecture with greatly enhanced piezoelectric output, the sound wave energy can be harvested under a sound pressure of 120+ dB SPL of electrical signal about 0.25 V. Furthermore, the simple throat vibrations such as hum, cough and swallow with different intensity or frequency can be distinguishably detected. Finally, the developed ultrathin ISSE of near-field electrospun piezoelectric fibers has the advantage of direct—write fabrication on highly flexible substrates and low cost. The proposed technique demonstrates the advancement of existing electrospinning technologies in new practical applications of sensing purposes such as voice control, wearable electronics, implantable human wireless technology.

We demonstrate that the thickness increase of the porous layer on p-type (1-10 ohm-cm) silicon can be inhibited from hundreds to several nm/min in regular anodizing by exposure to He-Ne laser irradiation. During 2.0 mW laser irradiation, the growth in thickness was reduced to 5-6 nm/minute by anodizing with a current density of 10 mA/cm 2 . The inhibition effect on the thickness increase of porous silicon depends significantly on the laser power during a fixed anodizing time.

This paper reports on a rapid, lossless process for the bonding of poly(methyl methacrylate) (PMMA) substrates for use in microfluidic devices for blood tests, utilizing H2O plasma, and H2O linked rapid thermal annealing (RTA) treatments. The bonding of PMMA produced with H2O plasma linked with RTA was analyzed, and its effect on the bonding of free radicals was investigated. The PMMA surface treatment was performed at constant RF power and H2O vapor flow but changing plasma treatment times in both processes. The surface modification of the PMMA subjected to the H2O plasma treatment was studied by optical emission spectroscopy, which confirmed that the relative intensity of hydroxyl radicals and oxygen emission peaks. The surface of the PMMA after being subjected to the plasma linked with RTA treatment was also characterized. The free energy increased with the plasma treatment time. The tensile test results revealed that the strength of OH bonds on the PMMA surface increased with a high plasma treatment time of 120 s. After bonding, UV–visible transmission spectrum measurements revealed that the transparency of the microfluidic device increased. We demonstrated the bonding of a microfluidic device with plasma treatment without deformation. This method provides an ideal bonding technique for the manufacture of microfluidic devices with PMMA. This technique has more advantages than other bonding techniques.

Numerous Si nanocrystals on the bulk surface can be efficiently sharpened by a HF-based electrochemical etching with the irradiation of near-infrared (NIR) laser simultaneously. Under the NIR laser-irradiation, the electrons excited from the B-Si complex inhibited the growth of the anodized layer and promoted the formation of nanocrystals by controlling the number of holes that participate in anodization. The effect of NIR laser-irradiation enhanced the photoluminescence by 7-10 times as compared to that obtained when anodization was performed in the dark for growing a normal porous silicon. The transmission electron microscopy images showed clearly that that nanocrystals (<3 nm) were embedded at the interface of the bulk surface and the anodized layer.

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