Suchergebnisse

Communities are the first line of defense in responding to major public health events. Taking the community-based prevention and control cases of COVID-19 in China as samples, this paper constructs an analytical framework for the generation of community-based prevention and control capacity of public health events from the perspective of governance elements optimization based on the methods of text analysis and limits-to-growth archetype analysis. According to the research, the community-based prevention and control of public health events realizes the integration of governance elements of key actors through the bureaucratic coordination mode and maximizes the prevention and control efficiency with the primary goal of epidemic prevention and control in a short period of time, which presents a "reinforcing feedback" loop in the "limits-to-growth" model system. However, with the development of the epidemic showing a strong trend of being latent and wide spread, the "reinforcing feedback" from the bureaucratic coordination model on the effect of epidemic prevention and control encounters the "regulatory feedback" that inhibits the growth at the data-driven level. On the basis of discussing the practice of the public health prevention and control mode in the grassroots communities under the established political framework, this paper attempts to construct an institutional reform system from technological governance to technological empowerment, so as to effectively realize the mode transformation of community-based prevention and control of public health events.

Thin-film solar cells based on hybrid lead halide perovskites have achieved certified power conversion efficiencies exceeding 24%, approaching those of crystalline silicon. This motivates deeper studies of the mechanisms that determine their performance. Twin defect sites have been proposed as a source of traps in perovskites, yet their origin and influence on photovoltaic performance remain unclear. It is found that twin defects-observed herein via both transmission electron microscopy and X-ray diffraction-are correlated with the amount of antisolvent added to the perovskite and that twin defects in the highest-performing perovskite photovoltaics are suppressed. Heterogeneous supersaturation nucleation is discussed as a contributor to efficient perovskite-based optoelectronic devices. ; The authors thank the Ministry of Science and Technology of Taiwan for support of this research (MOST 106‐2917‐I‐564‐007 and MOST 107‐2221‐E‐007‐055‐MY3). This publication is based in part on work supported by the US Department of the Navy, Office of Naval Research (Grant Award No. N00014‐17‐1‐2524), the Ontario Research Fund – Research Excellence Program, and the Natural Sciences and Engineering Research Council (NSERC) of Canada. M.I.S. acknowledges the support of the Banting Postdoctoral Fellowship Program, administered by the Government of Canada.