AIM: To investigate the behaviors of smartphone usage and parental knowledge of vision health among primary students in the rural areas of China. METHODS: In this school-based, cross-sectional study, a total of 52 606 parents of students from 30 primary schools in the Xingguo County were investigated through an online questionnaire from July 2020 to August 2020. The self-designed questionnaire contained three parts: the demographic factors of both children and parents, parental knowledge and attitude toward myopia, and the preventive treatment of myopia. RESULTS: A total of 52 485 appropriately answered questionnaires were received, showing an effective response rate of 95.1%. The average age of the primary students was 10.1±0.98y and the prevalence of myopia among the primary students was 40.3%. The age of myopia occurrence in elementary students was significantly correlated with the parents' educational level (95%CI: 0.82-0.98, P=0.013), children's gender (95%CI: 1.08-1.20, P<0.001), school location (county or countryside) (95%CI: 0.59-0.66, P<0.001), children's smartphone ownership (95%CI: 1.09-1.26, P<0.001), and the average time spent on smartphone per day (95%CI: 0.78-0.88, P<0.001). School location in the county town, high family income, and high parents' educational level significantly affected both parents' myopia awareness and children's vision-threatening behaviors (P<0.01). Left-behind children showed a higher incidence of vision-threatening habits than those who lived with their parents (P<0.01). CONCLUSION: The results reveal the current situation of myopia development among rural primary school students and their parents. This survey will serve as a guidance for designing myopic prevention policies in the rural areas of China.

Carbon fabric is proposed as the electrode support instead of Cu foil as the current collector in the fabrication of Si-anode, in order to prevent electrode pulverization during cell charge/discharge. Polyvinylpyrrolidone is used as a suitable dispersant to improve the anode slurry’s compatibility with the carbon fabric and final uniform distribution of the anode materials. The anode with added dispersant exhibits a lower resistance, and the constructed cell presents a higher capacity than that without dispersant in the anode (3561 vs 2755 mAh g−1) in the first charge/discharge cycle under a current of 420 mA g−1. After charge/discharge for 150 cycles, the stress from repeated formation/deformation of the solid-electrolyte interface layer only breaks a part of the fibers in the carbon fabric, while acceptable structural integrity is maintained in the anode. Interestingly, the added dispersant enhances both the uniform distribution of nano-Si electrode materials and the anode’s conductivity, while diminishing the fabric damage during charge/discharge cycles. This is attributed to the smaller, well-deagglomerated nano-Si particles that are better at sustaining the stress caused by cell charge/discharge, and also the binding force from the dispersant to reinforce the carbon fabric.

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