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In this study, we experimentally explored the impact outcomes of droplets under a wide range of Weber numbers (0.2 ≤ We ≤ 200) and contact angles (91° ≤ θ ≤ 162°). Five impact outcomes were identified: deposition, rebound, partial rebound, receding breakup, and prompt splash. Compared to the literature, we gathered more comprehensive data on the impact outcomes at various contact angles, which were then organized into a complete phase diagram. Furthermore, we corroborated the accuracy of these outcomes through comparisons with other studies. We conducted a comprehensive analysis of the associated phenomena and underlying mechanisms of these outcomes. By introducing the concept of surface hysteresis energy, we also proposed identification criteria for partial rebound. This innovative approach provides an important reference for further understanding of droplet impact behavior and provides guidance for future research in this field. [ABSTRACT FROM AUTHOR]

The cell performance of a proton exchange membrane fuel cell (PEMFC)-driven unmanned aerial vehicles (UAV) is affected by environmental changes during high-altitude flights. Therefore, the distribution of water and heat in a PEMFC was investigated. The result showed that the uniformity of temperature distribution on the membrane could be improved by increasing the air stoichiometry ratio, but the temperature difference on the membrane was still large and the minimum temperature difference was 14.6°C. When the temperature distribution is uniform, the temperature on the membrane is too low. Consequently, increasing the inlet temperature to 60°C, 70°C and 80°C resulted in inlet and outlet temperature differences of 3.5°C, 0.5°C and 2.7°C for the membrane respectively. By analyzing the distribution of the water content and temperature on the membranes, 70°C and 20 were considered to be the optimal inlet temperature and air stoichiometry, respectively. Under this condition, as the altitude increases, the temperature and water content on the membrane gradually decrease. [ABSTRACT FROM AUTHOR]

According to the principle that the oxidation chemical reaction between metal calcium film and water vapor makes calcium film transparent, this experiment measures the corrosion area of calcium film to characterize the quality of water vapor passing through high barrier plastic film, so as to measure the water vapor transmission rate of high barrier plastic film. The effects of corrosion time, thickness of calcium film and barrier property of samples on the determination of water vapor permeability were analyzed with vacuum evaporation calcium film as pretreatment method and regular monitoring of calcium corrosion area as detection method. The results show that at 40 °C and 90% RH, the high barrier and ultra-high barrier plastic films with a thickness of 200 nm and a nominal water vapor permeability of 10-6~10-3 g/(m2·24 h) at the initial stage of calcium corrosion show a good linear relationship between the calcium corrosion area and the water vapor permeability. The water vapor permeability is 1.2x10-3 g/(m2·24 h) and 9.3x10-7 g/(m2·24 h), respectively, with RSD of 11.6% and 16.5%. The results of water vapor transmission of high barrier and ultra-high barrier plastic films by calcium etching method are good, and this method has a high application prospect in the measurement of water vapor transmission of high barrier and ultra-high barrier packaging materials in electronic components, solar cells and organic light emitting diodes. [ABSTRACT FROM AUTHOR]

Mutations in the X-linked MECP2 gene cause Rett syndrome (RTT), an autism spectrum disorder characterized by impaired social interactions, motor abnormalities, cognitive defects and a high risk of epilepsy. Here, we showed that conditional deletion of Mecp2 in cholinergic neurons caused part of RTT-like phenotypes, which could be rescued by re-expressing Mecp2 in the basal forebrain (BF) cholinergic neurons rather than in the caudate putamen of conditional knockout (Chat-Mecp2(-/y)) mice. We found that choline acetyltransferase expression was decreased in the BF and that α7 nicotine acetylcholine receptor signaling was strongly impaired in the hippocampus of Chat-Mecp2(-/y) mice, which is sufficient to produce neuronal hyperexcitation and increase seizure susceptibility. Application of PNU282987 or nicotine in the hippocampus rescued these phenotypes in Chat-Mecp2(-/y) mice. Taken together, our findings suggest that MeCP2 is critical for normal function of cholinergic neurons and dysfunction of cholinergic neurons can contribute to numerous neuropsychiatric phenotypes.

Polymethacrylimide foams were prepared by free radical bulk polymerization with butyl methacrylate (BMA), acrylamide (AM) as the reactive monomer, acrylic acid (AA) as the third monomer and crosslinker at different heat treatment time. The structure and properties were characterized by FTIR, SEM, TGA and DSC. The results show that with the increase of heat treatment time of BMA/AM/AA copolymer, the rearrangement reaction between molecular chains produces a six-membered imide ring. After cross-linking and solidification, PMI foam is obtained. The characteristic absorption peaks are in good agreement with the literature values. After heat treatment for 5 h, a dense closed cell foam with a pore diameter of 100-200 μm is obtained, which has good mechanical properties, compressive strength of 8.160 MPa and tensile strength of 12.95 MPa. The glass transition temperature (Tg) of the foam is 255℃, the thermal decomposition temperature Td10 is as high as 280℃ when the thermal mass loss is 10%, and the foam still retains more than 80% at 345℃, and the thermal conductivity is 0.05424 W/(m·K). It is indicated that the foam with excellent high temperature resistance and thermal insulation properties is obtained after heat treatment of the copolymer for 5 h.