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Sun Q.,Chongqing UniversityChongqing | Zhang X.,Chongqing UniversityChongqing | Shu Y.,Chongqing UniversityChongqing | Tan L.,Chongqing UniversityChongqing | Liu Q.,Chongqing UniversityChongqing
Materials Letters | Year: 2016

Deformation twinning is one of the most important strain accommodation mechanisms for deformed hexagonal materials. The stacking faults inside the twin may act as obstacles to hinder the subsequent motion of the dislocations and accordingly influence the mechanical properties of materials. In the present work, two types of basal stacking faults within the {101¯2} deformation twin in a deformed magnesium alloy have been studied by high-resolution transmission electron microscopy. It has found that one ends of the basal stacking faults are usually bounded by the incoherent twinning boundaries. According to this experimental feature, the possible formation mechanisms of such basal stacking faults will be discussed. © 2016 Elsevier B.V.

Wang L.X.,Chongqing UniversityChongqing | Chen X.P.,Chongqing UniversityChongqing | Chen D.,Chongqing UniversityChongqing | Sun H.F.,Chongqing UniversityChongqing | Liu Q.,Chongqing UniversityChongqing
Materials Science and Engineering A | Year: 2016

The influence of preferential orientation (namely cube texture) on annealing twins in a cold rolled (95% thickness reduction) pure nickel has been investigated during isothermal annealing at low temperature. The results reveal that the cube oriented grains in cube related twinning (CT) regions have larger average boundary migration rate in comparison with grains in non-cube related twinning (NCT) regions. However, the twin density is always lower in CT regions than that in NCT regions. This is contrary to the growth accident model that suggests that twin density was proportional to the grain boundary velocity and grain boundary distance. It can be interpreted by the fact of the selective nucleation and growth mechanism for cube oriented grains which are less dependent on annealing twinning during recrystallization. Furthermore, during grain growth the average length of annealing twin boundary segments has a significant increment, which is probably attributed to lengthening of low energy twin boundaries along with the migration of other neighboring boundaries. © 2016 Elsevier B.V.

Sun Q.,Chongqing UniversityChongqing | Zhang X.Y.,Chongqing UniversityChongqing | Yin R.S.,Chongqing UniversityChongqing | Ren Y.,Chongqing UniversityChongqing | Tan L.,Chongqing UniversityChongqing
Scripta Materialia | Year: 2015

Using high-resolution transmission electron microscopy, we characterized the interfacial structure of {101¯3} twinning boundaries (TBs) in deformed cobalt, and found that TBs consist of {101¯3} TBs, {101¯1¯} TBs, basal-pyramidal (BPy) and pyramidal-basal (PyB) interfaces. The existence of {101¯1¯} TBs, BPy and PyB interfaces is responsible for the deviation of the actual {101¯3} TB from the theoretical twinning plane. Correspondingly, the migration of TBs attributed to the glide of twinning disconnections is discussed. © 2015 Acta Materialia Inc.

Yang Q.,Chongqing UniversityChongqing | Yang Q.,Guizhou University | Chen H.,Guizhou Normal University | Li B.,Chongqing UniversityChongqing
Archives of Environmental Contamination and Toxicology | Year: 2015

An investigation was performed to identify the sources of arsenic (As) and heavy metals in house dust and to assess the associated human health risks in the vicinity of phosphorus (P) mining in Guizhou, China. The concentrations and spatial distributions of mercury (Hg), As, cadmium (Cd), lead (Pb), iron (Fe), copper (Cu), manganese (Mn), and P in 23 house dust samples from the study area were determined. Greater concentrations of As and Pb were found compared with values in other investigations in various countries. Pollution sources were identified using multivariate statistical analysis. As, Pb, Mn, and Hg pollution was mainly attributed to mining activities, and Mn and Cd levels were largely associated with automobile emissions. The dominant wind direction and the distance of the residence from the mining region were found to play an important role in element distributions. A health risk assessment showed that As and Pb should be paid more attention, although the noncancer risks of the studied elements were within the safe range and the cancer risks of As and Cd are within the acceptable range under present conditions. © 2014 Springer Science+Business Media New York.

Zhou C.,Chongqing UniversityChongqing | Li M.,Chongqing UniversityChongqing | Hu Z.,Chongqing UniversityChongqing | Yin H.,Chongqing UniversityChongqing | And 2 more authors.
Journal of Crystal Growth | Year: 2016

In this study, a novel motion mode for crystals during growth, i.e., 2D translation, is proposed. Numerical simulations of flow and mass transfer are conducted for the growth of large-scale potassium dihydrogen phosphate (KDP) crystals subjected to the new motion mode. Surface supersaturation and shear stress are obtained as functions of the translational velocity, distance, size, orientation of crystals. The dependence of these two parameters on the flow fields around the crystals is also discussed. The thicknesses of the solute boundary layer varied with translational velocity are described. The characteristics of solution flow and surface supersaturation distribution are summarized, where it suggests that the morphological stability of a crystal surface can be enhanced if the proposed 2D translation is applied to crystal growth. © 2016 Elsevier B.V.

Zu Z.,Chongqing UniversityChongqing | Hu W.,Chongqing UniversityChongqing | Tang X.,Chongqing UniversityChongqing | Wang Yang P.H.,Chengdu University of Information Technology | And 4 more authors.
Materials Letters | Year: 2016

AgInZnS/RGO nanocomposites was prepared by a facile hot-injection method and the corresponding photoelectric detection device was further designed for studying the photoresponse property. The as-prepared AgInZnS/RGO nanocomposites was composed of AgInZnS nanoparticles of 7–8 nm and reduced graphene oxide (RGO) nanosheet. Moreover, the AgInZnS/RGO nanocomposites demonstrated slight red-shifted absorption and photoluminescence quenching, which could be attributed to the effective separation of photon-generated carrier of AgInZnS nanoparticles and fast electrical transportation of RGO sheet. Furthermore, the as-prepared AgInZnS/RGO nanocomposites showed relatively strong photoresponse, comparable short rise-time (0.62 s) and decay-time (0.29 s), which makes it as promising applications in photoelectric detection. © 2016 Elsevier B.V.

Wang T.,National University of Singapore | Yu Z.,Chongqing UniversityChongqing | Hoon D.L.,National University of Singapore | Huang K.-W.,King Abdullah University of Science and Technology | And 2 more authors.
Chemical Science | Year: 2015

Phosphine-catalyzed highly enantioselective γ-additions of 5H-thiazol-4-ones and 5H-oxazol-4-ones to allenoates have been developed for the first time. With the employment of amino-acid derived bifunctional phosphines, a wide range of substituted 5H-thiazol-4-one and 5H-oxazol-4-one derivatives bearing heteroatom (S or O)-containing tertiary chiral centers were constructed in high yields and excellent enantioselectivities. The reported method provides facile access to enantioenriched tertiary thioethers/alcohols. The mechanism of the γ-addition reaction was investigated by performing DFT calculations, and the hydrogen bonding interactions between the Brønsted acid moiety of the phosphine catalysts and the "C=O" unit of the donor molecules were shown to be crucial in asymmetric induction. This journal is © The Royal Society of Chemistry.

Ren J.,Nanjing University of Information Science and Technology | Ren J.,University of Southern Denmark | Ren J.,Chongqing UniversityChongqing | Dong L.,Japan National Institute of Environmental Studies | And 7 more authors.
Renewable and Sustainable Energy Reviews | Year: 2015

This study investigates Chinas biofuel industry-the third largest in the world-by combining a strength, weakness, opportunity and threats (SWOT) analysis with a method known as fuzzy analytic hierarchy process (FAHP). More specifically, the study employs SWOT analysis to identify the influential factors affecting the development of the biofuel industry in China. It then prioritizes their importance using the FAHP method. The study finds that high production costs, competition with other renewable energy resources, inconsistent policy and legislation support, and poor technical standards are impeding the growth of the biofuel industry of China. The study concludes by proposing strategic recommendations for how the industry can be made both leaner, more efficient and effective, and greener, more socially and environmentally sustainable. Some of these options focuses on improving technical perform, adhering to a "supply push" mentality. Others focus on improving affordability and consumer awareness, adhering to a "demand pull" mentality. © 2015 Elsevier Ltd. All rights reserved.

Cao K.,Zhejiang University | Kuang M.,Chongqing UniversityChongqing | Zhang Y.,Chongqing UniversityChongqing | Liu J.,Zhejiang University | And 2 more authors.
Materials Research Bulletin | Year: 2016

Nanostructure is believed to produce great benefits for anode materials in lithium ion batteries (LIBs) by enhancing lithium ion transfer, accommodating large volume change and increasing surface area. Whether the nanostructure (especially the porous nanostructure) could be well held during charging/discharging process is one of the most commonly concerned issues in LIBs research. The dynamic evolution of birnessite manganese dioxides nanosheets during lithiation process is investigated by in-situ transmission electron microscopy (TEM) for the first time. The TiO2@MnO2 core-shell nanowires are used as the anode and Li metal as the counter electrode inside the TEM. Interestingly, the lithiation process is confirmed as MnO2 and Li converting to Li2O and Mn. The original porous structure of the nanosheets is hard to preserve during lithiation process due to lithiation-induced contact flattening. © 2016 Elsevier Ltd. All rights reserved.

Li T.,Chongqing UniversityChongqing | Zeng W.,Chongqing UniversityChongqing | Zhang Y.,Chongqing UniversityChongqing | Hussain S.,Chongqing UniversityChongqing
Materials Letters | Year: 2015

Abstract We report the synthesis of novel nest-like MoO3 hierarchical structures with nanobelts as building blocks via a facile hydrothermal process. A comparison study reveals that an enhanced gas sensing performance for the sensor made of nanobelt-assembled nest-like MoO3 towards ethanol occurs over that of the monodispersed MoO3 nanobelts. The improved gas sensing properties are mainly attributed to the well-aligned nanoporous structures with a less stacking configuration, which provides sufficient nano or micro reaction rooms for chemical reaction as well as effective diffusion channels for gases. © 2015 Elsevier B.V.

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