Directional transport of liquid droplets is crucial for various applications including water harvesting, anti-icing, and condensation heat transfer. Here, bouncing of water droplets with patterned superhydrophobic surfaces composed of circular equidistant grooves was studied. The directional transport of droplets toward the pole of the grooves was observed. The impact of the Weber number, initial polar distance r, and geometrical parameters of the surface on the directional droplet bouncing was experimentally explored. The nature of bouncing was switched when the Weber numbers exceeded We ≅ 20−25. The rebouncing height was slightly dependent on the initial polar coordinate of the impact point for a fixed We, whereas it grew for We > 20. The weak dependence of the droplet spreading time on the Weber number was close to the dependence predicted by the Hertz bouncing, thus evidencing the negligible influence of viscosity in the process. Change in the scaling exponent describing the dependence of the normalized spreading time on the Weber number was registered for We ≅ 25. The universal dependence of the offset distance ΔL of the droplets on the Weber number ΔL/D 0 ∼ We 1.5 was established. The normalized offset distance decreased with the normalized initial polar distance as ΔL/D 0 ∼ (r/S) −1 , where D 0 and S are the droplet diameter and groove width, respectively. This research may yield more insights into droplet bouncing on patterned surfaces and offer more options in directed droplet transportation.

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The train-mounted ethylene propylene rubber (EPR) cables of electric locomotive are partly restricted by the body structure and spatial layout and are in a combined environment of strong mechanical bending and thermal ageing. The degradation characteristics of the insulation layer have not yet received sufficient attention. In order to study the ageing characteristics of EPR cables of electric locomotive under the combined action of machine and thermal, this paper designs a bending-thermal combined ageing test platform for cables with a temperature of 135°C, bending diameter of 393.52 mm, 590.28 mm and unbending cables, and tests after ageing. The product has been tested by infrared spectroscopy, scanning electron microscopy, elongation at break and broadband dielectric spectroscopy. The research results show that the bending outer part of the train-mounted EPR cable is a pain point. Under the combined action of bending and thermal, whether it is microstructure or macro performance, the degradation rate and degree of the bending of outer insulation layer are greater than the value under a single thermal ageing condition. Mechanical bending has an accelerating effect on the ageing of the EPR insulation layer. The research results can provide a reference for the ageing characteristics of the train-mounted EPR cable under the bending-thermal synergy and the evaluation of operating state of the train-mounted EPR cable under bending-thermal operating conditions.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

E-commerce companies have been already using their website to increase company popularity, advertise products, do online marketing and receive orders online. However, how a company web pages serves its function as a communication window with their customers always concerns trading companies. This paper, based on the experts consultation and customer opinions, combined with the literature review, establishes an evaluation indicator system of e-commerce web page quality. Also, an evaluation model is created to analyze the factors that will influence web page quality of trading company on the basis of BP neural network. Test results show that the BP neural network model is precise, stable and practical.

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