Porous Nanofibers Formed by Heterogeneous Growth of ZnO/Ag Particles and the Enhanced Photocatalysis.

Porous ZnO/Ag nanofibers with unique multi-interface contact structures have been synthesized by an electrospinning method. The composite nanofibers with the length of several hundred micrometers are composed of uniformly distributed ZnO and Ag nanoparticles in the size range 10~30 nm. Notably, a heterogeneous growth in the interface of ZnO and Ag particles occurs. The MO degradation rate of ZnO/Ag nanofibers with Ag content of 18 wt.% is 100% in 10 min under UV-vis irradiation and that of ZnO/Ag nanofibers with Ag content of 15 wt.% is 92% in 40 min under simulated day light, which is two times that of the pure ZnO. It is attributed to a special structure that improves the generation and separation efficiency of the photo-generated charges by the expansion of the absorption edges, the utilization efficiency of the surface plasmon resonance (SPR) oscillations of Ag, and the effective transferring of electrons from ZnO through the heterogeneous-growth interface. No obvious loss of the photocatalytic activity is observed after five cycles, indicating the excellent photostability of ZnO/Ag nanofibers. The work sheds light on the structure design of highperformance composite photocatalysts.

Graphitic Carbon Nitride (g-C3N4) Nanosheets/Graphene Composites: In Situ Synthesis and Enhanced Photocatalytic Performance.

A facile In Situ growth method was presented here for the preparation of graphitic carbon nitride (g-C3N4)/graphene composites, in which the direct growth and deposition of g-C3N4 nanosheets from organic N and C sources on the graphene surfaces was achieved to form the 3D contacted structure. The resulting 3D architecture possessed multilevel porous structure and efficient g-C3N4/graphene interfaces, which facilitated the fast electron transfer at the interfaces. Photoluminescence spectra showed that the recombination of photogenerated electrons and holes in the g-C3N4/graphene composites was greatly inhibited by the introduction of graphene, indicating the more efficient separation of electrons and hole in the g-C3N4/graphene composites than in pure g-C3N4. The catalytic activity of g-C3N4/graphene composite photocatalyst was enhanced by over two fold compared to pure g-C3N4 for removal of Rhodamine B under simulated sun light irradiation. This work indicates that the metal-free g-C3N4/graphene composite photocatalyst is a promising nanomaterial for further applications in water treatment.

Observation of stimulated emission from a single Fe-doped AlN triangular fiber at room temperature.

Aluminum nitride (AlN) is a well known wide-band gap semiconductor that has been widely used in fabricating various ultraviolet photo-electronic devices. Herein, we demonstrate that a fiber laser can be achieved in Fe-doped AlN fiber where Fe is the active ion and AlN fiber is used as the gain medium. Fe-doped single crystal AlN fibers with a diameter of 20-50 µm and a length of 0.5-1 mm were preparated successfully. Stimulated emission (peak at about 607 nm and FWHM ~0.2 nm) and a long luminescence lifetime (2.5 ms) were observed in the fibers by a 532 nm laser excitation at room temperature. The high quality long AlN fibers are also found to be good optical waveguides. This kind of fiber lasers may possess potential advantages over traditional fiber lasers in enhancing power output and extending laser wavelengths from infrared to visible regime.

Useful information for hypertension management reform in community health care: prevalence, awareness, treatment and control among Guangzhou adults.

BACKGROUND: Objective data on hypertension prevalence and management in local areas are scarce. We assessed the prevalence of hypertension and its management in Guangzhou adult population. METHODS: A stratified multistage cluster sampling with probability proportional to size method was used in this survey. Information on a total of 23 939 respondents, aged 15 years old or above, having a gender ratio of 0.997 (male versus female) with completed questionnaire and blood pressure measurement, was obtained. Hypertension was defined as having a mean SBP of at least 140 mm Hg, a DBP of at least 90 mm Hg, and/or the prescription of antihypertensive drugs. Information related to the history of hypertension and treatment of hypertension was collected through a questionnaire. RESULTS: The prevalence of hypertension was 11.8%. Among patients with hypertension, 54.4% were aware of their elevated BP, 49.3% had treatment, and 23.3% achieved targeted BP control. Among those who were aware of their hypertension, 90.4% underwent treatment, and among those who were treated, 43.6% were well controlled. Although the prevalence, awareness and treatment of hypertension varied significantly among adults with several social economics status, the control of hypertension did not show significant differences. Among treated patients, the control of hypertension showed significant differences among adults with education, occupation, insurance and income. CONCLUSIONS: It is the first time for Guangzhou to describe epidemic and management of hypertension. A baseline was established, which could provide useful information not only to policymakers but also to developing countries with a close urbanization and aging rate similar to Guangzhou.

Effects of Co and Mn doping in K0.8Fe2-ySe2 revisited.

Accumulated evidence indicates that phase separation occurs in potassium intercalated iron selenides, a superconducting phase coexisting with the antiferromagnetic phase K2Fe4Se5, the so-called '245 phase'. Here, we report a comparative study of substitution effects by Co and Mn for Fe sites in K0.8Fe2-ySe2 within the phase separation scenario. Our results demonstrate that Co and Mn dopants have distinct differences in occupancy and hence in the suppression mechanism of superconductivity upon doping of Fe sites. In K0.8Fe2-xCoxSe2, Co prefers to occupy the lattice of the superconducting phase and suppresses superconductivity very quickly, obeying the magnetic pair-breaking mechanism or the collapse of the Fermi surface nesting mechanism. In contrast, in K0.8Fe1.7-xMnxSe2, Mn shows no preferential occupancy in the superconducting phase or the 245 phase. The suppression of superconductivity can be attributed to restraining of the superconducting phase and meanwhile inducing another non-superconducting phase by Mn doping.

Synthesis and characterization of NiO nanowire/In2O3 nanoparticle heterostructures.

A facile method is presented for synthesis of novel pearl-string-like NiO nanowire/In2O3 nanoparticle heterostructures. The synthesis was carried out by using a chemical vapor deposition method with Indium granules and Nickel (II) Chloride Hexahydrate as precusors. The structures were investigated by X-ray diffraction and transmission electron microscopy. Room and low temperature photoluminescence of the heterostructures was studied. Our work provides a new strategy for fabrication of novel nano-heterostructures and is promising for future device applications.

Heterogeneous ZnS hollow urchin-like hierarchical nanostructures and their structure-enhanced photocatalytic properties.

Hexagonal wurtzite ZnS nanowires radially arrayed on cubic zinc-blende ZnS hollow spheres have been successfully achieved for the first time, and such novel heterogeneous ZnS hollow urchin-like hierarchical nanostructures show greatly enhanced photocatalytic properties due to their two-phase enhanced light-harvesting and high surface-to-volume ratio.