This article was accepted for publication in the journal Carbon [© Elsevier]. The definitive version is available at: http://dx.doi.org/10.1016/j.carbon.2013.08.032.The three different sized chemical functionalized graphene (GO) sheets, namely GO-1 (D50 = 10.79 μm), GO-2 (D50 = 1.72 μm) and GO-3 (D50 = 0.70 μm), were used to fabricate a series of epoxy/GO nanocomposites. Fracture toughness of these materials was assessed. The results indicate that GO sheets were dramatically effective for improving the fracture toughness of the epoxy at a very significant low loading. The enhancement of the epoxy toughness was strongly dependent on the size of GO sheets incorporated. GO-3 with smaller sheet size gave the maximum reinforcement effect compared with GO-1 and GO-2. The incorporation of only 0.1 wt% GO-3 was observed to increase the fracture toughness of pristine epoxy by ∼75%. The toughening mechanism was well understood by fractography analysis of the tested samples. Massive cracks in the fracture surfaces of the epoxy/GO nanocomposites were observed. The GO sheets effectively disturbed and deflected the crack propagation due to its two dimensional structure. GO-3 sheets with smaller size were highly effective in resisting crack propagation, and a large area of whitening zone was observed. The incorporation of GO also enhanced the stiffness and thermal stability of the epoxy

With the wide application of nuclear energy, the problem of radioactive pollution has attracted worldwide attention, and the research on the treatment of radioactive wastewater is imminent. How to treat radioactive wastewater deeply and efficiently has become the most critical issue in the development of nuclear energy technology. The radioactive wastewater produced after using nuclear technology has the characteristics of many kinds, high concentration, and large quantity. Therefore, it is of great significance to study the treatment technology of radioactive wastewater in reprocessing plants. The process flow and waste liquid types of the post-treatment plant are reviewed. The commonly used evaporation concentration, adsorption, precipitation, ion exchange, biotechnology, membrane separation, and photocatalysis are summarized. The basic principles and technological characteristics of them are introduced. The advantages and disadvantages of different single and combined processes are compared, and the development trend of future processing technology is prospected.

Two-dimensional materials have gained great attention as a promising thermoelectric (TE) material due to their unique density of state with confined electrons and holes. Here, we synthesized 1T phase tungsten disulfide (WS ₂ ) nanosheets with high TE performance via the hydrothermal method. Flexible WS ₂ nanosheets restacked thin films were fabricated by employing the vacuum filtration technique. The measured electrical conductivity was 45 S cm ⁻¹ with a Seebeck coefficient of +30 μ V K ^–1 at room temperature, indicating a p-type characteristic. Furthermore, the TE performance could be further improved by thermal annealing treatment. It was found the electrical conductivity could be enhanced 2.7 times without sacrificing the Seebeck coefficient, resulting in the power factor of 9.40 μ W m ⁻¹ K ⁻² . Moreover, such 1T phase WS ₂ nanosheets possess high phase stability since the TE properties maintained constant at least half one year in the air atmosphere. Notably, other kinds of 1T phase transitional metal dichalcogenides (TMDCs) with excellent TE performance also could be imitated by using the procedure in this work. Finally, we believe a variety of materials based on 1T phase TMDCs nanosheets have great potential as candidate for future TE applications.