ABSTRACT
Double emulsions are of great importance for both science and engineering. However, the production of multicore double-emulsion droplets is challenging and normally requires sophisticated microfluidic devices, which limits their availability to broader communities. Here, we propose a simple, precise, and scalable batch method for producing double emulsions with monodispersed multicores at milliliter per minute rates, using the most common means in laboratory, temperature. By rapidly cooling liquid crystal emulsions, the introduced temperature gradient around the emulsion droplets leads to the injection of monodispersed guest droplets to form double-emulsion droplets. The number of injected water droplets can be precisely controlled by adjusting the thermally induced mechanical force through the temperature difference and the cooling rate. In contrast to conventional microfluidic fabrication, this method processes all emulsion droplets simultaneously in a noncontact and in situ manner. Therefore, it has great flexibility, allows multiple processing of double emulsions of arbitrary shape, has good capacity for mass production, and offers excellent compatibility with technologies such as microfluidics. Finally, we demonstrate that temperature changes can also be used to release the inner droplets from the double emulsion. The proposed method offers a reversible tool for processing double emulsions with minimal cost and expertise and is applicable to droplet-based microsystems in materials science, photonics, sensors, pharmaceuticals, and biotechnology.
ABSTRACT
Ecological compensation in the Yellow River Basin aims to improve its ecological and environmental management capacity. Based on data on land-use changes in the Yellow River Basin from 2010 to 2020, this study used the equivalent factor method to assess the value of ecosystem services in the basin. This was measured at three spatial scales in the upper, middle, and lower reaches, encompassing; nine provinces and 72 cities. The priority and amount of ecological compensation were determined for the Yellow River Basin regions. Results show that (1) The total value of ecosystem services in the Yellow River Basin increased from 1798.317 billion yuan in 2010 to 1838.259 billion yuan in 2020. Grasslands had the highest total ecosystem service value in 2020, accounting for 46.11%. (2) The value of ecosystem services in the Yellow River Basin region is upstream > midstream > downstream. Qinghai Province has the highest value of ecosystem services among the nine provinces, and the level of economic development in each region is inversely correlated with the value of ecosystem services. (3) The ecosystem service value and the economic development level of the cities in the Yellow River Basin are positively and negatively correlated with the priority of ecological compensation, respectively. Among them, the cities in the upper reaches are the most urgent targets for national ecological compensation. (4) The total ecological compensation in the Yellow River Basin in 2020 was approximately 122.63 billion yuan. Further, the amount of vertical ecological compensation to be paid by the state was approximately 114.673 billion yuan, and the horizontal compensation to be borne between provinces was approximately 7.957 billion yuan. The findings of this study provide novel insights into improving ecological compensation in the Yellow River Basin regions.
