Using a Coupled Human-Natural System to Assess the Vulnerability of the Karst Landform Region in China

Guizhou Plateau is a region in China that typically shows the contradictory human-earth system. A vulnerability assessment indicator system was constructed to explore the coupled human-natural system characteristic of the karst landform based on the grey correlation analysis mathematic model. The quantitative assessment results show that Qiandongnan and Tongren Districts belong to the slight degree of the sensitivity evaluation index. Bijie district belongs to the middle degree and the other districts of Guizhou Plateau belong to the light degree. In terms of the exposure and resilience evaluation index, only Guiyang City belongs to the slight degree and other districts are in the middle degree. Thus, Guizhou Plateau could be divided into three level zones based on the comprehensive vulnerability degree of the coupled human-natural system. The strong degree vulnerability zone includes Liupanshui City, Bijie City, Anshun City, and Qiannan District. The middle degree vulnerability zone includes the districts of Qiandongnan, Qianxinan, and Tongren and the city of Zunyi. The slight degree vulnerability zone only includes Guiyang City. The research results suggest that the coupled human-natural system in Guizhou Plateau has a high vulnerability

Tunable plasmon resonances of Ag nanoparticles obtained by photoelectric modification under room temperature

Stretched Ag nanoparticles (AgNPs) have been obtained by photoelectric modification with room temperature. Significant elongation occurs on partial AgNPs with diameters ranging from 50 to 120 nm. For AgNPs with diameters larger than 120 nm, protuberances with sizes about 10 nm have been observed after photoelectric modification. Simulations based on finite difference time domain method have been used to reveal the process of the photoelectric modification. Such morphology changes of AgNPs can be attributed to the plasmonic phase transition and electric induced migration of Ag atoms at AgNPs surfaces. Due to the stretching of AgNPs, tunable plasmon resonances in visible spectrum have been obtained. This work could provide a new technology for the metallic nanostructure modification under low temperature

ZnO/Carbon Shell/Carbon Cloth as a Stable Host for High Li-Content Anodes

Among all energy storage systems, lithium metal batteries (LMBs) show great advantages in terms of energy density. Nevertheless, the challenges of lithium metal anodes, namely, dendrite formation and low Coulombic efficiency, hinder the practical application of LMBs. In this work, we used the ZnO/carbon shell/carbon cloth as a host for the lithium metal anode. The introduction of ZnO sites reduces the nucleation barrier of lithium deposition, and the existence of a 3D current collector alleviates the volume change during lithium plating/stripping. In addition, the combination of ZnO/C and 3D carbon cloth decreases the local current density and contributes to uniform lithium plating/stripping. The half cells assembled with modified carbon cloth electrodes cycle for more than 125 cycles with a high Coulombic efficiency of 99.34%, even under a high areal capacity of 6 mA h cm–2. By and large, our work provides a simple and effective strategy to modify the current collector for high Li-content anodes