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Abstract Irrigated agriculture has important implications for achieving the United Nations Sustainable Development Goals. However, there is a lack of systematic and quantitative analyses of its impacts on food–energy–water–CO 2 nexus. Here we studied impacts of irrigated agriculture on food–energy–water–CO 2 nexus across food sending systems (the North China Plain (NCP)), food receiving systems (the rest of China) and spillover systems (Hubei Province, affected by interactions between sending and receiving systems), using life cycle assessment, model scenarios, and the framework of metacoupling (socioeconomic-environmental interactions within and across borders). Results indicated that food supply from the NCP promoted food sustainability in the rest of China, but the NCP consumed over four times more water than its total annual renewable water, with large variations in food–energy–water–CO 2 nexus across counties. Although Hubei Province was seldom directly involved in the food trade, it experienced substantial losses in water and land due to the construction of the South-to-North Water Transfer Project which aims to alleviate water shortages in the NCP. This study suggests the need to understand impacts of agriculture on food–energy–water–CO 2 nexus in other parts of the world to achieve global sustainability. 

Abstract A series of polymer nanocomposites containing single‐walled carbon nanotubes (SWNTs) are prepared from polymerizable quaternary ammonium surfactants using photo‐polymerization and investigated by means of polarized optical microscopy, small‐angle X‐ray scattering, and rheological measurements. The surfactant monomers with various alkyl chains of nonpolar tails form lyotropic liquid crystalline (LLC) mesophases in aqueous medium with hexagonal packing of cylindrical micelles. The physical adsorption of nonpolar tails of surfactants on the surface of SWNTs results in de‐bundled nanotubes. The LLC phase diagram is investigated as functions of alkyl chain length, concentration, temperature, and SWNTs. As such, addition of SWNTs does not change the hexagonal mesophases but enhances the order–disorder transition temperatures and alters the rheological behaviors. After photo‐polymerization, the microstructures of hexagonal packing are changed while addition of SWNTs does not disrupt the resulting microstructures. The polymerized composites are consistent with both lamellar and gyroid nanostructures and a possible model is proposed to interpret the observed phenomenon. Under the shear flow, the defect‐free monodomain structures are obtained in the LLC phase and subsequently locked in the solid film after polymerization.