An Illumination-Assisted Flexible Self-Powered Energy System Based on a Li-O2 Battery.

The flexible Li-O2 battery is suitable to satisfy the requirements of a self-powered energy system, thanks to environmental friendliness, low cost, and high theoretical energy density. Herein, a flexible porous bifunctional electrode with both electrocatalytic and photocatalytic activity was synthesized and introduced as a cathode to assemble a high-performance Li-O2 battery that achieved an overpotential of 0.19 V by charging with the aid of solar energy. As a proof-of-concept application, a flexible Li-O2 battery was constructed and integrated with a solar cell via a scalable encapsulate method to fabricate a flexible self-powered energy system with excellent flexibility and mechanical stability. Moreover, by exploring the evolution of the electrode morphology and discharge products (Li2 O2 ), the charging process of the Li-O2 battery powered by solar energy and solar cell was demonstrated.

[Spatial dispersion laws of fugitive dust from construction sites].

Dust fall was selected as a monitored index of fugitive dust from construction sites. The vertical dispersion law of fugitive dust was studied nearby construction site's boundary by monitoring the concentration variation of dust fall at different heights from 1.5 meters to 4.1 meters. The horizontal dispersion law of fugitive dust was studied along different distance between monitoring points and construction site from 0 meters to 210 meters. We gained the vertical and horizontal dispersion models of fugitive dust by regressing measurement date. The results showed that the concentration of relative dust fall from construction site was proportional to second power of monitoring height, and relative dust fall at uniform height and direction was also proportional to second power of level distance between monitoring points and construction site. The vertical and horizontal dispersion constants are mainly affected by construction activity and natural condition.

[Correlation between dust fall and TSP from construction sites].

This paper studied the correlation between dust fall and TSP from construction sites in Beijing by statistically analyzing a large number of field measurement data. The results show that there are better linear correlations between dust fall and TSP from construction fugitive dust, and the correlation between dust fall and TSP at construction sites' boundary can be expressed by the function: c(TSP) = 11.6 x c(DF). The distance between monitoring site and fugitive dust source performs a considerable influence on the correlation coefficients that is proportional to the distance. However, construction phases' influence is lesser.

[Characteristics of fugitive dust pollution in different construction phases].

More than forty construction sites were selected as experimental fields in urban districts and near suburbs of Beijing. Fugitive dust from construction sites was monitored by dust fall. The characteristics of fugitive dust pollution in different construction phases were studied. The frequency distribution of relative dust fall date in different construction phases were statistically analyzed, and the results show that fugitive dust pollution in earthwork phase is more serious than those in structure and decoration phases. There are higher probabilities of high strength fugitive dust pollution in earthwork and decoration phases comparing with structure phase, and the probabilities of relative dust fall which is more than 50 t/(km2 x 30 d) are 16%, 16% and 3% respectively. Different construction phases all comply with the laws that fugitive dust pollution strength in spring is bigger than summer,autumn and winter obviously, and winter is bigger than summer and autumn appreciably. There are obvious relation of fugitive dust pollution strength in different construction phases, and the ratio of pollution strength in earthwork, structure and decoration phases equals to 100:67:87.