11 research outputs found

    Evaluation of the Temporal and Spatial Changes of Ecological Quality in the Hami Oasis Based on RSEI

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    Given the restrictions on special geographic locations in development processes, the measurement and analysis of the ecological quality of the Hami Oasis are of great significance for the protection of this fragile oasis. In this study, the ecological quality of the Hami Oasis was monitored by constructing a remote sensing ecological index (RSEI) for arid areas. Using the standard deviation ellipse and moving window method, the ecological status and space–time changes were explored for both their external and internal factors in the Hami Oasis. Finally, a geo-detector was employed to determine the driving factors of the ecological quality of the Hami Oasis. The results revealed that: (1) In the remote sensing ecological index constructed in the Hami Oasis, the main influencing factors were dryness and wetness. The average value of the ecological quality of the oasis was less than 0.5, and the ecological quality level was relatively poor. Among the five grades of ecological quality in the Hami Oasis, the poor grade and the good grade showed the largest changes, decreasing by 200 and increasing by 300, respectively, which were mainly concentrated in the periphery of the oasis. (2) The improved ecological quality of the Hami Oasis was mainly manifested in the expansion of the artificial oasis, while the deteriorated area was manifested as an increase in the built-up area. Moreover, the ecological quality of the Hami Oasis presented a ringlike nesting distribution pattern from the internal built-up area to the artificial oasis periphery. (3) The external expansion direction of the ecological quality of the Hami Oasis featured southeast–northwest expansion, which was consistent with the direction of the rivers and traffic roads. The transformation between different ecological qualities in the oasis and the expansion of the built-up area were the reasons for the fragmentation of the Hami Oasis’ landscape. (4) Compared to a single factor, the dual-factor for the ecological quality of the Hami Oasis had stronger explanatory power. Moreover, changes in land use types caused changes in the ecological quality of the Hami Oasis. During the study period, we found that human activities had a more significant impact than natural factors on the development of the Hami Oasis. (5) The Moran’s I Index increased from 0.835268 in 2000 to 0.923976 in 2018, and the p values in the study area all reached a 0.05 significant level. At the same time, the areas with p values above the 0.01 and 0.001 significant levels have also increased significantly in the past 18 years

    Halide precursor reduction strategy to modulate bismuthene with high selectivity and wide potential window for electrochemical CO2 reduction

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    Developing high-performance electrocatalysts for CO2 reduction reaction (CO2RR) is vital in achieving a carbon-neutral society by converting CO2 into valuable chemicals. CO2RR electrocatalyst with lower overpotential, higher selectivity and wider working potential range is urgently desired, but it is still challenging to realize these factors simultaneously. Here, high-performance bismuthene-based electrocatalysts were synthesized by reducing bismuth precursors like BiCl3, BiBr3, and BiI3 in liquid phases. Especially, bismuthene-I derived from BiI3 showed a nanosheet morphology (around four-layer) with significantly enhanced (110) surfaces. It enabled an ultrawide potential window (0.7 V) for high formate selectivity (>90%) in a H-type cell and achieved an ultralow potential (−0.46 V vs. reversible hydrogen electrode) to attain a current density of 200 mA cm−2 in a gas-diffusion flow cell. The prominent long-term operational capability of bismuthene-I was demonstrated in both H-type and gas-diffusion cells. Density functional theory calculations revealed that bismuthene-I possessed abundant topological Bi(110) surfaces states that can reduce the CO2RR overpotential, suppress the competitive hydrogen evolution reaction, and facilitate electron donation during CO2 electrocatalysis. The bismuthene-I realized low overpotential, high selectivity and wide working potential range simultaneously for electrochemical CO2RR. This work unfolds the broader plausibility of facilely reducing precursors for the scalable fabrication of high-performing CO2RR electrocatalysts

    Intraoperative hypothermia and its clinical outcomes in patients undergoing general anesthesia: National study in China.

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    Inadvertent intraoperative hypothermia (core temperature 2 h) (OR = 2.60, 95% CI 2.09-3.24).The incidence of intraoperative hypothermia in China is high, and the rate of active warming of patients during operation is low. Hypothermia is associated with more postoperative shivering, increased ICU admissions, and longer postoperative hospital days
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