The development of flexible, wearable electronic devices is one of the future directions of technology development. Flexible conductive materials are important supporting materials for wearable electronic devices. Polymer has excellent flexibility; it is an important way to prepare flexible conductors from polymer-based conductive composites. In this paper, the research progress of polymer-based flexible conductive composites is summarized in terms of preparation and characterization methods. The key factors to realize flexible conductors are put forward, namely, the maintenance of excellent polymer elasticity and the realization of stability. The design and preparation of the extensible conductor with high-elasticity matrix and nanofiller are introduced in detail, and the problems in the current research are summarized.

Benzoxazine resin, a new type of phenolic resin, has many advantages, such as a strong molecular design, no small molecular release in the curing process, excellent thermal stability and mechanical properties, and a high residual carbon ratio. Thus, it is important for electronic communication industry matrix material. To meet the needs of high-frequency and high-speed communication technology for low-dielectric polymer resin, the low-dielectric modification of benzoxazine resin is of great significance to the high frequency and high-speed propagation of the signal, which attracts a wide range of materials researchers’ attention. In this paper, we review a series of studies on the low dielectric modification of benzoxazine resin in recent years, including the synthesis of new monomers, inorganic - organic hybridization, copolymerization with other resins, and low molecular weight benzoxazine resin research trends.

Salicylaldehyde imine transition metal catalyst is a kind of olefin polymerization catalyst that is widely used in the coordination of salicylaldehyde imine ligand and pre-transition metal. Salicylaldehyde imine ligands have the characteristic of easily inserting different substituents via organic synthesis. Therefore, the regulation of the polymerization activity, polymerization product, and product distribution can be achieved by changing the steric hindrance effect, the electronic effect, and the number of metal active sites near the catalytic active center. The development status of the transition metal catalyst of salicylaldehyde imide was summarized in this paper. The influence of the ligand structure of the salicylaldehyde imide transition metal catalyst on the catalytic performance, which involved the high selectivity of ethylene trimerization, ethylene/α-olefin, polar monomer copolymerization, ethylene polymerization production, ultra-high molecular weight polyethylene, and many other areas of olefin polymerization, was elaborated, providing references for further study and industrial applications of this catalyst.

Influenced by global financial crisis in 2008, many countries around the world have realized the significance of sustainable development. And green development, as the most important pathway to sustainability, has been implemented by various countries. In this context, green development has drawn great attention from academic researchers both at home and abroad in recent years and has become an interdisciplinary-oriented research direction. As an applied basic research field for exploring the structural change of resources and environment as well as regional sustainable development, geography plays an essential role in the research of green development. Based on an intensive literature review, this article firstly summarized the connotation and analytical framework of green development. Secondly, it systematically outlined the progress of green development research from the perspective of geography and thus extracted seven themes, that is, the influencing factors of green development, assessment methods, spatial and temporal characteristics of green development, green development and industrial transformation, green transformation of resource-based cities, the effect of green development, and green development institutions and recommendations. Comments were made on the existing studies including their shortcomings. Finally, future research emphases were discussed, aiming to provide references for further study on green development from the perspective of geography in China.

Forests have ecological functions in water conservation, climate regulation, environmental purification, soil and water conservation, biodiversity protection and so on. Carrying out forest ecological quality assessment is of great significance to understand the global carbon cycle, energy cycle and climate change. Based on the introduction of the concept and research methods of forest ecological quality, this paper analyzes and summarizes the evaluation of forest ecological quality from three comprehensive indicators: forest biomass, forest productivity and forest structure. This paper focuses on the construction of evaluation index system, the acquisition of evaluation data and the estimation of key ecological parameters, discusses the main problems existing in the current forest ecological quality evaluation, and looks forward to its development prospects, including the unified standardization of evaluation indexes, high-quality data, the impact of forest living environment, the acquisition of forest level from multi-source remote sensing data, the application of vertical structural parameters and the interaction between forest ecological quality and ecological function.

The sea level rise under global climate change and coastal floods caused by extreme sea levels due to the high tide levels and storm surges have huge impacts on coastal society, economy, and natural environment. It has drawn great attention from global scientific researchers. This study examines the definitions and elements of coastal flooding in the general and narrow senses, and mainly focuses on the components of coastal flooding in the narrow sense. Based on the natural disaster system theory, the review systematically summarizes the progress of coastal flood research in China, and then discusses existing problems in present studies and provide future research directions with regard to this issue. It is proposed that future studies need to strengthen research on adapting to climate change in coastal areas, including studies on the risk of multi- hazards and uncertainties of hazard impacts under climate change, risk assessment of key exposure (critical infrastructure) in coastal hotspots, and cost-benefit analysis of adaptation and mitigation measures in coastal areas. Efforts to improve the resilience of coastal areas under climate change should be given more attention. The research community also should establish the mechanism of data sharing among disciplines to meet the needs of future risk assessments, so that coastal issues can be more comprehensively, systematically, and dynamically studied.