Fe3O4@SiO2 magnetic nanoparticles modified by grafting poly(1-vinylimidazole) oligomer (FSPV) was fabricated as a novel adsorbent to remove Hg(II) from water. Fourier transform infra-red spectroscopy confirmed the successful grafting of oligomer, and thermogravimetric analysis showed FSPV had a high grafting yield with organic content of 22.8%. Transmission electron microscopy image displayed that FSPV particles were polymer-coated spheres with size of 10–20 nm. With saturation magnetization of 44.7 emu/g, FSPV particles could be easily separated from water with a simple magnetic process in 5 min. The Hg(II) adsorption capacity of FSPV was found to be 346 mg/g at pH 7 and 25 °C in 10 mM NaCl. Moreover, the removal of Hg(II) by FSPV was not obviously affected by solution pH (from 4 to 10) or humic acid (up to 8 mg/L as TOC). The presence of seven common ions including Na+, K+, Ca2+, Mg2+, Cl−, NO3−, and SO42− (up to 100 mM ionic strength) slightly increased the adsorption of Hg(II) by FSPV. X-ray photoelectron spectroscopy analysis revealed that the N atom of the imidazole ring was responsible for the bonding with Hg(II), whereas the bonding of Hg with N did not result in cleavage of Hg–Cl bond in HgCl2 and HgClOH. The regeneration of Hg(II)-loaded FSPV could be achieved with 0.5 M HCl rapidly in 10 min, and the removal of Hg(II) maintained above 94% in five consecutive adsorption–desorption cycles. Therefore, FSPV could serve as a promising adsorbent for Hg(II) removal from water.
Ye et al. have determined a maximum nitrous acid (HONO) yield of 3% for the reaction HO2 center dot H2O + NO2, which is much lower than the yield used in our work. This finding, however, does not affect our main result that HONO in the investigated Po Valley region is mainly from a gas-phase source that consumes nitrogen oxides.
[6,6]-Phenyl-C61-butyric acid-4'-hydroxyl-azobenzene ester (PCBAb) was synthesized and used as the acceptor in the fabrication of reversible UV-VIS response bi-state polymer solar cells (PSCs) based on the photoinduced cis-trans isomerization of PCBAb. The device can be switched between ``active'' and ``sleep'' by the irradiation of UV and visible light, respectively. The active device has a PCE of 2.0%. With UV irradiation, the device goes to ``sleep'' with a lowered PCE (0.4%), and simultaneously decreased J(sc), V-oc and FF, while after visible light treatment, the device is made ``active'' again. The mechanism of the bi-state process involves the different electron mobilities of the isomers. (C) 2015 Elsevier B.V. All rights reserved.
Eutrophication has become a top environmental issue for most lake ecosystems in the world and enhanced phosphorus (P) input is usually considered the primary stressor. Focused on the role of phosphorus in eutrophic lakes, a bibliometric approach was applied to quantitatively evaluate the main interests of research and trends in this area. Using data from the Science Citation Index Expanded database between 1900 and 2013, a total of 3,875 publications was returned by searching topic keywords. Spatial, temporal, and interactive characteristics of the articles, countries, and keywords are presented using time series, frequency, and co-occurrence analysis. Result shows that the annual publications on P in eutrophic lakes keep an exponential growth (R (2) = 0.93; p < 0.0001) over the last two decades, reflecting an increasing attraction in this area. However, publications of phosphorus research make up only 40 % of total records in eutrophic lakes, indicating that there are other significant topics in eutrophication problems of lakes. The USA is the largest output country in this area, contributing 23 % of the total articles, followed by China with a proportion of 15 %. However. China has replaced the USA as the largest output country in the world since 2011, but its citation per paper is significantly lower than the USA, indicating its' favor on quantity over quality. Based on international cooperation analysis, five regional groups were found, and the USA, the UK, P.R. China, Sweden, and German are the centers of their groups. The top 20 title keywords, author keywords and keywords plus were identified according to their frequency to assist our understanding of interests of research and modes. Surprisingly, nitrogen is a high co-occurrence keyword in this study, and its share of publications with P research in eutrophic lakes is increasing rapidly. Furthermore, the high correlation between P and N research in spatial distribution also indicates the increasing significance of N research in eutrophic lakes.
Ma S, Huang T, Gao W. The second generation IEEE 1857 video coding standard, in IEEE China Summit and International Conference on Signal and Information Processing, ChinaSIP 2015, Chengdu, China, July 12-15, 2015.; 2015:171–175. 访问链接
China has recently launched a radical reform to transform over 600 regional universities into application and technology oriented institutions. The reform is a response to diverse labour market demands, regional economic development and the suboptimal structure of the higher education system, and uses international experiences as a reference. While China is still struggling to identify proper international models to follow, this article offers a potential candidate - Finland, with respect to Finnish experiences recommendations for the Chinese reform are discussed and elicited. The analysis flows from discussions in a series of seminars and workshops held in Finland and China in 2014. This article argues that the Finnish experience is of relevance to Chinese regional university transformation, notwithstanding the huge difference in scale.