Hierarchical nanostructures with SnO(2) backbones and ZnO branches are successfully prepared in a large scale by combining the vapor transport and deposition process (for SnO(2) nanowires) and a hydrothermal growth (for ZnO). The ZnO nanorods grow epitaxially on the SnO(2) nanowire side faces mainly with a four-fold symmetry. The number density and morphology of the secondary ZnO can be tailored by changing the precursor concentration, reaction time, and by adding surfactants. Photoluminescence (PL) properties are studied as a function of temperature and pumping power. Such hybrid SnO(2)-ZnO nanostructures show an enhanced near-band gap emission compared with the primary SnO(2) nanowires. Under the optical excitation, a UV random lasing is observed which originates from the hierarchically assembled ZnO branches. These three-dimensional nanostructures may have application potentials as chemical sensors, battery electrodes, and optoelectronic devices.
Graphene has attracted much attention since its first discovery in 2004. Various approaches have been proposed to control its physical and electronic properties. Here, it is reported that graphene‐based intercalation is an efficient method to modify the electronic properties of few‐layer graphene (FLG). FeCl3 intercalated FLGs are successfully prepared by the two‐zone vapor transport method. This is the first report on full intercalation for graphene samples. The features of the Raman G peak of such FLG intercalation compounds (FLGIC) are in good agreement with their full intercalation structures. The FLGICs present single Lorentzian 2D peaks, similar to that of single‐layer graphene, indicating the loss of electronic coupling between adjacent graphene layers. First principle calculations further reveal that the band structure of FLGIC is similar to single‐layer graphene but with a strong doping effect due to the charge transfer from graphene to FeCl3. The successful fabrication of FLGIC opens a new way to modify properties of FLG for fundamental studies and future applications.
Since the 1960s, more than 20,000 compounds were discovered from marine organisms. In this paper we performed a quantitative analysis for the novel marine natural products reported between 1985 and 2008. The data was extracted mainly from the reviews of Faulkner and Blunt [1–26]. The organisms producing these marine natural products are divided into three major biological classes: marine microorganisms (including phytoplankton), marine algae and marine invertebrate. The marine natural products are divided into seven classes based on their chemical structure: terpenoids, steroids (including steroidal saponins), alkaloids, ethers (including ketals), phenols (including quinones), strigolactones, and peptides. The distribution and the temporal trend of these classes (biological classes and chemical structure classes) were investigated. We hope this article provides a comprehensive perspective on the research of marine natural products.
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