Lithium⁃sulfur batteries are expected to become the next generation of specific energy storage batteries to replace lithium⁃ion batteries due to their significant advantages such as high specific capacity, high energy density, low cost, and environmental friendliness. However, the practical application of lithium⁃sulfur batteries is severely limited by a series of problems existing in electrode materials, such as lower ion/electron conductivity, shuttle effect of polysulfides, large volume changes during charge and discharge, and the stability of lithium anodes and so on. Combining sulfur with various carrier materials to improve the utilization of active materials and battery cycle stability has become a current research hotspot. Among the reported carrier materials, metal organic frameworks with rich pores and open active sites and their derivative materials have attracted wide attention because of their excellent structural characteristics. This review summarized the recent research progress of metal organic frameworks and their derivatives in improving the cycle stability of sulfur cathodes, and prospected its development trends in lithium⁃sulfur batteries.

Based on the 22 listed companies in general aviation indicator data, DEAMalmquist index method for static and dynamic efficiency analysis was used. The results showed that in 2012 77% of the sample making general aviation listed companies was less than 1.000 in comprehensive efficiency, and the pure technical efficiency and the scale efficiency had not reached the optimal state, resulting in low efficiency of its comprehensive sample did not become a benchmark for enterprises. The period of 20082012 only five companies TFP index greater than 1.000, all the sample enterprises emerged in the phenomenon of regression techniques. Therefore, the technology regression in general aviation companies was the major obstacle. Consequently, the technology progress would be a realistic choice in improving our operating performance level And finally the corresponding recommendations were given.