Strong cladding mode excitation in ultrathin fiber inscribed Bragg grating with ultraviolet photosensitivity.

Strong UV-written Bragg gratings written in 50 µm-diameter cladding single mode fibers compatible with conventional fiber couple core guided light to dozens of cladding modes distributed across 140 nm in the 1400-1600 nm region, without the need for complex symmetry breaking mechanisms such as tilted, laterally offset, or localized gratings. The extent of the coupling to high order modes and the smaller cladding diameter both contribute to increasing the sensitivity to surrounding refractive index changes by more than one order of magnitude, and to an increased spacing between mode resonances to facilitate unambiguous measurements of larger index changes between 1.3 and 1.44. These improvements are confirmed by theoretical and experimental studies that also cover the temperature and strain differential sensitivities of the cladding mode resonances for complete multiparameter sensing capability.

The state-of-the-art research of the application of ultrasound to winemaking: A critical review.

As a promising non-thermal physical technology, ultrasound has attracted extensive attention in recent years, and has been applied to many food processing operation units, such as involving filtration, freezing, thawing, sterilization, cutting, extraction, aging, etc. It is also widely used in the processing of meat products, fruits and vegetables, and dairy products. With regard to its application in winemaking, most of the studies available in the literature are focused on the impact of ultrasound on a certain characteristic of wine, lacking of systematic sorting of these literatures. This review systematically summarizes and explores the current achievements and problems of the application of ultrasound to the different stages of winemaking, including extraction, fermentation, aging and sterilization. Summarizing the advantages and disadvantages of ultrasound application in winemaking and its development in future development.

Roles of free radical on the formation of acetaldehyde in model wine solutions under different ultrasound parameters: A key bridge-link compound for red wine coloration during ageing.

In order to explore the effects of ultrasound on the formation of acetaldehyde and its mechanism in model wine solutions, ultrasound conditions and free radicals were investigated by response surface methodology and electron paramagnetic resonance spectroscopy (EPR), respectively. The results indicate that ultrasound does induce the production of acetaldehyde with the maximum amount under the conditions of ultrasound power density 0.2 W/cm2, 48 min and 32 °C. The hydroxyl radicals and the 1-hydroxyethyl free radicals are the main initiator and precursor for acetaldehyde, respectively. Furthermore, the stronger the 1-hydroxyethyl free radicals captured by EPR, the lower the formation of acetaldehyde. In addition, the content of Fe2+and ethanol also exerted a certain influence on the acetaldehyde formation. In conclusion, ultrasound does promote the production of acetaldehyde in the model wine solutions, which is beneficial for well understanding the mechanism of ultrasound in modifying the wine color and accelerating ageing.