Equity is one of the essential objectives of the social health insurance. This article evaluates the benefit distribution of the China's Urban Residents' Basic Medical Insurance (URBMI), covering 300 million urban populations. Using the URBMI Household Survey data fielded between 2007 and 2011, we estimate the benefit distribution by the two-part model, and find that the URBMI beneficiaries from lower income groups benefited less than that of higher income groups. In other words, government subsidy that was supposed to promote the universal coverage of health care flew more to the rich. Our study provides new evidence on China's health insurance system reform, and it bears meaningful policy implication for other developing countries facing similar challenges on the way to universal coverage of health insurance.

No abstract

Sodium-ion batteries (SIBs) have attracted significant research interest for large-scale electric energy storage. However, anodes with good rate capability and long cycle life are still lacking. Here, a three-dimensional (3D) porous Sn on Cu foil (Sn/Cu) is prepared by tuning the redox potential of Cu /Cu with a ligand of thiourea to trigger the replacement reaction between Cu and Sn . The as-synthesized Sn/Cu is used as an integrated porous electrode and can be directly applied as an advanced freestanding electrode for SIBs. Such a unique structure can efficiently relieve the strain caused by sodiation/desodiation and benefit penetration of the electrolyte and diffusion of Na . This is a merit of its large reversible capacity of about 700 mAh g at 2500 mA g for 400 cycles. A full battery of Sn/Cu//Na (VO ) (PO ) F is constructed, which presents a high energy density of 311.7 Wh kg and long lifespan of 200 cycles. This facile synthesis strategy and good electrochemical performance will encourage more investigations into structure design of functional materials.

AbstractMolecular dynamics (MD) analysis of methane hydrate is important for the application of methane hydrate technology. This study investigated the microstructure changes of sI methane hydrate and the laws of stress–strain evolution under the condition of compression and tension by using MD simulation. This study further explored the mechanical property and stability of sI methane hydrate under different stress states. Results showed that tensile and compressive failures produced an obvious size effect under a certain condition. At low temperature and high pressure, most of the clathrate hydrate maintained a stable structure in the tensile fracture process, during which only a small amount of unstable methane broke the structure, thereby, presenting a free-motion state. The methane hydrate cracked when the system reached the maximum stress in the loading process, in which the maximum compressive stress is larger than the tensile stress under the same experimental condition. This study provides a basis for understanding the microscopic stress characteristics of methane hydrate.