Flexible omnidirectional reflective film for CO_(2)laser protection

In this Letter,we presented a flexible omnidirectional reflective film made of polymer substrates and multiple alternating layers of two chalcogenide glasses for full-angle CO_(2) laser protection.The structure parameters of the device were simulated for theoretical prediction of best device structure.The reflector was fabricated by alternate thermal evaporation of two chalcogenide glasses with large refractive index contrast.The reflectivity was greater than 78%at 10.6μm.The flexible reflective film can provide an effective solution for full-angle CO_(2) laser protection of the moving targets,such as laser operators and mobile optical components,with potential applications for wearable laser protective clothing.

Effect of Bag Removing with Reflective Film Mulching Before Harvest on Fruit Coloration and Expression of Anthocyanin Related Genes in Peach

Appearance quality is the main element forming the fruit quality. Both bagging and reflective film application can improve appearance comprehensive quality. In order to determine the effects of bagging and reflective film on peach fruit coloration, this study explored the effects of applying reflective film before harvest on fruit appearance quality of peach(Prunus persica), and discussed the influencing mechanism on fruit coloration. Yellow outside and black inside double-layer bags were removed from fruit twelve days d before harvest. Peel color, pigment content, enzyme activity as well as the gene expression related to fruit coloration of a well-colored and late-ripening peach cultivar ‘Xiahui 8' with different treatments(non-bagging with non-reflective film mulching, debagging with non-reflective film mulching, debagging with reflective film mulching) were researched. The results showed that both debagging with non-reflective film mulching and debagging with reflective film mulching could significantly improve red and green color difference value(a*), a*/b*(b* is yellow and blue color difference value), chroma(C), anthocyanin(Ant) content and reduce hue angle(h), while debagging with reflective film mulching had higher Ant content than debagging with non-reflective film mulching(P < 0.05). The two treatments up-regulated the transcript level of anthocyanin biosynthetic related genes(UFGT, CHS) at the beginning of the experiment, however, the expression of DFR, LDOX and F3 H were enhanced along with the testing process. A downward trend on peel phenylalanine ammonia lyase(PAL) activity of non-bagging with non-reflective film mulching was observed during the experiment, however, the peel PAL activity of the other two treatments first increased and then decreased. What's more, peel PAL activity of debagging with reflective film mulching was higher than debagging with non-reflective film mulching. These results suggested that Ant synthesis in the peel was the result of cooperation among several genes, and debagging with reflective film mulching had better effect on promoting Ant accumulation than debagging with non-reflective film mulching.

Dedicated SiPM array for GRD of GECAM

Purpose The discovery of gravitational waves and gamma-ray bursts heralds the era of multi-messenger astronomy.With the adoption of two small satellites to achieve the all-sky monitoring of gamma-ray bursts,the gravitational wave highenergy electromagnetic counterpart all-sky monitor(GECAM)possesses a quasi-real-time early warning ability and plays an important role in positioning the sources of gravitational waves and in subsequent observations.Each satellite of GECAM was fitted with 253-inch-diameter gamma-ray detectors(GRD),covering an energy range of 8–2 MeV.GRDs have adopted silicon photomultiplier tubes(SiPM)in lieu of photomultiplier tubes(PMT)to adapt to the dimensional limitations of micro-satellites.Methods A unique 3-inch circular SiPM array was designed.In this design,646×6 mm chips were arranged evenly in a circular manner with the seams filled with reflecting films,thus achieving satisfactory uniformity of light collection.The integrated pre-amplifier circuit on the back of the SiPM array adopted two-level grouping and summing;further,it achieved a satisfactory signal-to-noise ratio.Two high-gain and low-gain channels were adopted to achieve a large dynamic range,and two independent power supply units were used,where each unit can be closed separately,thus improving reliability.Results Performance studies show that this SiPM array meets the requirements of GECAM.Conclusion A 3-inch SiPM array have been developed that uses grouped summation,reflective films,a circular arrangement,two groups of independent power supplies,high-and low-gain signals,differential signal output technologies,etc.This solution can be used not only for GECAM,but also as a general solution for SiPM-based scintillation detectors.