Spatial variations in the N2O emissions and denitrification potential of riparian buffer strips (RBS) in a polluted river were examined. The river received large pollutant inputs from urban runoff and wastewater discharge, resulting in impaired water quality in the river and downstream reservoir. The potential for nitrogen removal by RBS was evaluated by measuring in situ N2O emission fluxes in static closed chambers and sediment denitrification potentials with acetylene inhibition techniques. The results showed that N2O emission fluxes decreased from the upstream (16.39 μg/(m2·h)) to downstream (0.30 μg/(m2·h)) sites and from the water body to upland sites. The trend in decreasing N2O emission fluxes in the downstream direction was mainly associated with sediment/soil textures (clay loam→sandy soil) and sediment/soil water contents and was also related to the vegetation along the RBS and nutrients in the sediments/soils. The correlation coefficient was highest (r=0.769) between the N2O emission flux and sediment/soil water content. Sediment/soil denitrification potentials under N-amended and ambient conditions were higher (highest 32.86 mg/(kg·h)) for the upstream sites, which were consistent with in situ N2O flux rates. © 2013 Copyright Taylor and Francis Group, LLC.

TiO2, well known for its photocatalytic properties, has also been studied as a safer anode material for lithium ion batteries compared to graphite. However, improvements are needed to address the limited lithium ion diffusion within the host and the structural distortion during lithium insertion/extraction. Here, we demonstrate that a thin layer of hydrogenated surface disorder on the crystalline TiO2 electrode induces better electrochemical energy storage performance, better charge/discharge rate performance, larger capacity and longer stability. The reasons for these improvements are explored in terms of the facilitation of lithium ion transport within the disordered layer and the alleviation of structural distortion during the lithium insertion/extraction process, and the faster ion exchange rates in the hydrogenated disordered layer. © 2013 Elsevier Ltd.

Magnetoelectric coupling in ferromagnetic/multiferroic systems is often manifested in the exchange bias effect, which may have combined contributions from multiple sources, such as domain walls, chemical defects, or strain. In this study we magnetically "fingerprint" the coupling behavior of CoFe grown on epitaxial BiFeO3 (BFO) thin films by magnetometry and the first-order-reversal-curves (FORC). The contribution to exchange bias from 71°, 109° and charged ferroelectric domain walls (DWs) was elucidated by the FORC distribution. CoFe samples grown on BFO with 71° DWs only exhibit an enhancement of the coercivity, but little exchange bias. Samples grown on BFO with 109° DWs and mosaic DWs exhibit a much larger exchange bias, with the main enhancement attributed to 109° and charged DWs. Based on the Malozemoff random field model, a varying-anisotropy model is proposed to account for the exchange bias enhancement. This work sheds light on the relationship between the exchange bias effect of the CoFe/BFO heterointerface and the ferroelectric DWs, and provides a path for multiferroic device analysis and design.