Min Shang

Waste electrical and electronic equipment (WEEE), also called electronic waste or e-waste, the core of “urban mining”, is attracting more and more attention to its pollution control and circular recycling. Hence, we defined WEEE, preliminarily discussed its history in China and pointed out that China has made great achievements in WEEE circular reutilization and pollution control. Meanwhile, we analyzed the four levels of circular WEEE recycling: repair, reuse and remanufacture, waste-to-materials, waste-to-products and waste-to-energy, and also put forward questions during this process. Moving forward, WEEE management will turn to intelligent management targeted on hazardous waste and other pollution, not merely the guidelines. Meanwhile, WEEE technology will transfer to value-added and automated reutilization, not just simple dismantling.

The increasing rate of sandy desertification lands in Zoige County has been regarded as an imminent threat recently. There is an urgent need to monitor the status, trend of desertification. This study used a land cover classification process of integrating Support Vector Machine classifier (SVM) with threshold method to extract the sandy lands based on Landsat data collected from 1990 to 2017. Furthermore, we quantitatively analyzed the evolution trend of the grassland desertification and verified the effect of desertification control using the unmanned aerial vehicle (UAV) image acquired in 2019. Three conclusions are drawn from the study. First, the sandy land is mainly distributed along the directions of prevailing wind at the edges of mountains in the southwest. Second, the area of sandy lands increased from 29.75 km2 in 1990 to 46.87 km2 in 2005 and then decreased to 22.58 km2 in 2013. While during 2014-2017, the area increased to 33.61 km2. Third, the increasing of sandy lands is closely related to the terrain and water resources distribution. Ecological restoration policies, especially the ecological recovery projects implemented are the main driving factor of desertification reversion. The results of this study can provide effective data and decision support for combating desertification.