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Environmental regulation could affect many aspects of production and operation of companies. Company performance is an important index to measure its operation. We use a quasi-natural experiment to explore how government environmental auditing influence company performance in China from 2003 to 2017. The results illustrate that environmental auditing could improve company performance. This effect is more significant in state-owned company and private company than in foreign and other company. It also influence more significantly on companies with low technical level than high technical level. The difference of internal control level of a company does not have significant influence on the impact of environmental auditing on company performance. We further examine the moderate impact of innovation. The result shows that under the supervision of government auditing, the performance of companies with high innovation ability would be better.

The mental health problem of middle and old people cannot be ignored, while depression is a common but serious mental illness that affects the health of the elderly. In order to find the optimal social activity which seniors would like to do to decrease their depression, this research employed 5 different models onto elderly longitudinal study from 4 different countries. Based on database analysis and detailed interpretation, the research found suitable approaches to prevent senior depression in different countries and communities.

The bi-directional DC / DC converter in DC microgrid is a typical nonlinear system which has large voltage disturbance during lead accumulator charging and discharging. In order to solve the problem of voltage disturbance, the linearization of the converter is realized by exact feedback linearization, and the sliding mode controller is designed by using exponential approximation law. The simulation results show that the method has fast response speed, strong anti-interference ability and good steady-state characteristics.