The spontaneous combustion of coal in goaf is the main cause of mine fire at present. Lignite has become a major hidden danger in mine production safety because of its easy oxidation. In this paper, an innovative strategy was proposed to inhibit the spontaneous combustion of lignite by using the principle of microbial-induced calcium deposition. Based on the optimized culture method, a novel composite inhibitor of Bacillus pasteurelli was prepared. SEM, pore size analysis and FT-IR experiments were carried out simultaneously, and the oxidation properties of lignite before and after inhibition were quantitatively characterized from the perspective of microstructure, and the flame retardant properties of microbial and chemical retardants on coal samples were compared. The results show that a large number of deposited calcium carbonate particles are obviously attached to the surface of lignite after microbial inhibition treatment, which plays a physical oxygen insulation role. At the same time, the total pore volume and specific surface area of the coal sample decreased by 68.49% and 74.01%, respectively, indicating that microbial inhibitors can effectively plug the primary pores of lignite. Based on the peak measurement of 400-4000cm-1 infrared spectrum of coal samples, it is found that the contents of active groups including hydroxyl, carboxyl and methyl/methylene in lignite molecules after microbial inhibition are lower than those in raw coal, especially the methyl/methylene content involved in the initial oxidation reaction decreased by 96.5% compared with the baseline content in raw coal. The results show that the oxidation and self-heating capacity of lignite after microbial inhibition is effectively restrained in the initial spontaneous combustion. The research results of this paper can provide effective solutions for the prevention and control of coal spontaneous combustion risk in mined-out area.

Social media addiction has attracted the attention of researchers especially during the COVID era because negative emotions generated from the pandemic may have increased social media addiction. The present study aimed to investigate the role of negative emotions and social media addiction on health problems during and after the COVID lockdown. A survey was conducted with 2926 participants aged between 25 and 45 years. The data collection period was between 2nd September and 13th October 2020. Partial Least Square Structural Equation Modeling was conducted for data analysis by controlling the respondents' working time, leisure time, gender, education, and age. Our study showed that social media addiction and time spent on social media impact health. Interestingly, while anxiety about COVID increased social media addiction, fear about COIVD reduced social media addiction. Also, long working hours contributed most to people’s health issues, and its impact on social media addiction and hours was much higher than negative emotions, where males faced more health challenges than females. The impacts of negative emotions generated by the COVID on social media addiction and health issues should be reconsidered. Government and employers' control of people's working time stress should prioritize solving social media addiction-related issues.