Utility of stream mesocosms for climate change research

The utility of stream mesocosms was examined in a study of replicability of water physicochemstry and benthic macroinvertebrate assemblages in an array of artificial flumes near the River Itchen in southern U.K. High quality groundwater supply and similar exposure to the environment lead water physicochemistry to be highly replicate across all channels. The within- and between-flume replicate design reduced macroinvertebrate assemblages’ variability temporally, but the structure of macroinvertebrate assemblages in mesocosms shift seasonally. The highly temporal replicability of mesocosms allowed a long-term (i.e. 1- year) study of drought in these stream mesocosms. Seven water depth treatments were applied in a series (n=21) of artificial flumes to construct a linear varying drought gradient so that each treatment was replicated three times. The drought experiment lasted a course from August, 2013 to August, 2014. Algal growth and the abundance of three grazer taxa were negatively correlated with both drought intensity and drought duration. Additionally, the drought intensity impact on algal growth shifted with drought duration. Conversely, drought intensity had a fixed negative impact on decomposition process. Shredder community structure was altered by drought impact reducing shredder abundance and shredding efficiency. However, the shredding efficiency in freshwater ecosystem was more related to shredding efficiency of specialist shredder rather than shredder abundance. The mesocosms could mimic freshwater ecosystem physiochemistry environment and macroinvertebrate assemblage effectively and comprehensively, which provided an access to study the impact of natural disturbance on freshwater ecosystem. This study developed the understanding of the drought effect on the entire freshwater ecosystem

1D NiHPO4 nanotubes prepared using dissolution equilibrium as bifunctional electrocatalyst for high-efficiency water splitting

In this work, one-dimensional NiHPO4 nanotubes are successfully fabricated on nickel foam by hydrothermal reaction, in which a dissolution equilibrium between phosphates is controlled by tuning the proportion of the mixed solvent and amounts of KOH. As the dissolution equilibrium is broken, the morphology of NiHPO4 transfers from solid nanowires to hollow nanotubes. The resulting 1D NiHPO4 nanotubes exhibit good electrocatalytic activity and stability in oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Notably, a water-splitting voltage of 1.62 V at a current density of 10 mA cm 2 is obtained in an electrolyzer setup assembled using 1D NiHPO4 nanotubes as cathode and anode, demonstrating NiHPO4 nanotubes are promising catalysts for overall water splitting. Moreover, the revealed mechanism of forming tube morphology can be extended to fabricate other metal phosphates with hollow structures

The second fusion of laser and aerospace—an inspiration for high energy lasers

Since the first laser was invented, the pursuit of high-energy lasers (HELs) has always been enthusiastic. The first revolution of HELs was pushed by the fusion of laser and aerospace in the 1960s, with the chemical rocket engines giving fresh impetus to the birth of gas flow and chemical lasers, which finally turned megawatt lasers from dream into reality. Nowadays, the development of HELs has entered the age of electricity as well as the rocket engines. The properties of current electric rocket engines are highly consistent with HELs’ goals, including electrical driving, effective heat dissipation, little medium consumption and extremely light weight and size, which inspired a second fusion of laser and aerospace and motivated the exploration for potential HELs. As an exploratory attempt, a new configuration of diode pumped metastable rare gas laser was demonstrated, with the gain generator resembling an electric rocket-engine for improved power scaling ability