Limited and uneven distributed water resources have become one of the main obstacles to China's sustainable development, and the "virtual water hypothesis" (VWH) is expected to help mitigate water... Show moreLimited and uneven distributed water resources have become one of the main obstacles to China's sustainable development, and the "virtual water hypothesis" (VWH) is expected to help mitigate water stress. This study discusses the virtual water transfer pattern and water resources stress in China from the VWH perspective. Economic sectors in China are divided into land-dependent sectors and non-land-dependent sectors according to their dependence on specific local land types. Furthermore, the water resources withdrawal and utilization corresponding to these sectors are divided into land-dependent water resources (LDW) and non-land-dependent water resources (NLDW). Results show that the virtual LDW flows from economically poor to relatively developed regions, while the virtual NLDW flows in the opposite direction. LDW dominates Chinese water stress (78.2%) and virtual water flow (74.5%). Furthermore, the virtual water dominated by LDW ameliorates national water stress (the population under unsustainable water stress declined by 0.21 billion) but aggravates the imbalance of water resources between North and South. The transfer of virtual NLDW alleviates this imbalance slightly. Suitable land conditions play a decisive role in LDW withdrawal, which then cannot be replenished by virtual water. However, the withdrawal and transfer of NLDW are flexible, which should be a focus. The results point out that the possibility of water-rich regions as virtual water exporters is the key to alleviating the North-South water resource imbalance in China with VWH theory. Improvement of land productivity and water efficiency can be helpful to alleviate water stress. These findings may provide new insight into China's virtual water transfer pattern from the VWH perspective. Show less
Lu, H.; Rossi, M.; Nag, A.; Osada, M.; Li, D.F.; Lee, K.; ... ; Lee, W.S. 2021
The discovery of superconductivity in infinite-layer nickelates brings us tantalizingly close to a material class that mirrors the cuprate superconductors. We measured the magnetic excitations in... Show moreThe discovery of superconductivity in infinite-layer nickelates brings us tantalizingly close to a material class that mirrors the cuprate superconductors. We measured the magnetic excitations in these nickelates using resonant inelastic x-ray scattering at the Ni L-3-edge. Undoped NdNiO2 possesses a branch of dispersive excitations with a bandwidth of approximately 200 milli-electron volts, which is reminiscent of the spin wave of strongly coupled, antiferromagnetically aligned spins on a square lattice. The substantial damping of these modes indicates the importance of coupling to rare-earth itinerant electrons. Upon doping, the spectral weight and energy decrease slightly, whereas the modes become overdamped. Our results highlight the role of Mottness in infinite-layer nickelates. Show less
Lee, W.S., Zhou, K.; Hepting, M.; Li, J.; Nag, A.; Walters, A.C.; Garcia-Fernandez, M.; ... ; Devereaux, T.P. 2021
