A mild template-free aqueous route was successfully established to synthesize well-aligned ZnO nanorod arrays, which were proved to exhibit high optical property by PL spectra.

Single-walled carbon nanotube (SWCNTs) is a promising material candidate for fabricating highperformance electrodes in electrochemical capacitors. An intriguing question is what are the key material characteristics of SWCNTs that influence the performance of SWCNT-based capacitors? We grafted SWCNTs with different amounts of carboxylic groups by a surfactant free method. Their density was quantified using a fluorescence labeling method, ranging from 7.3 to 353.2 nmol m À2 . SWCNTs were also characterized by scanning electron microscope, N 2 physisorption, ultraviolet-visible-near-infrared absorption, Fourier transform infrared, Raman, and X-ray photoelectron spectroscopy. Functionalized SWCNTs show a minor increase in their microspores and mesopores volume, and the total surface area stays $322.8 m 2 g À1 . We correlated SWCNT physiochemical properties with the performance of assembled twoelectrode SWCNT capacitors. The specific capacitance, power density and energy density increase with increasing carboxylic group density, reaching the maximum at 146.1 F g À1 , 308.8 kW kg À1 and 13.0 Wh kg À1 at the density of $250-350 nmol m À2 . Potentiostatic electrochemical impedance spectroscopy analysis reveals that introducing an appropriate concentration of carboxylic groups plays two key roles: (1) it decreases the surface resistivity of SWCNT films, thus significantly reducing the equivalent series resistances of capacitors and (2) it enhances the surface wettability of SWCNTs, which not only offers more accessible sites for the physisorption of free electrolyte ions on SWCNT surfaces, but also increases ionic conductivity at electrode-electrolyte interfaces. These results and analysis provide a fundamental understanding of the effect of functionalization on the performance of SWCNT-based electrochemical capacitors, and shed light on a pathway by which electrochemical capacitors can be further improved for practical applications.

Bi 2 S 3 nanowire/CdS nanoparticle heterostructure has been designed and constructed through an easy wetchemistry approach at 140 °C for 8 h. The product is mainly composed of Bi 2 S 3 nanowires, several hundred nanometers long and 10 nm wide, and epitaxially grown triangle-like CdS nanoparticles with size of 20 nm at their surfaces. A possible sequential deposition growth mechanism is proposed on the basis of experimental results to reveal the formation of the nanoscale heterostructure. Under the irradiation of UV light, the as-prepared nanoscale Bi 2 S 3 /CdS heterostructure exhibits enhanced photochemical efficiency that can be mainly attributed to the microstructure of the product. In the nanoscale heterostructure, the CdS nanoparticle not only determines the overall band gap energy, but also controls the charge carrier transition, recombination, and separation, while the Bi 2 S 3 nanowire serves as support for the CdS nanoparticle, defines the specific surface area of the product and thus influences the photocatalytic activity. The effects of reaction parameters on the structure and photocatalytic activity of the final product are also discussed.

A novel nanocomposite with a core-shell structure containing polystyrene (PS), polyaniline (PANI), and Au nanoparticles (NPs) was synthesized. The nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). Cyclic voltammetric experiments indicated that the nanocomposite had excellent redox ability in a wide range of pH values. The existence of Au NPs resulted in a higher electrical conductivity of the nanocomposite. As a model, glucose oxidase (GOD) was entrapped onto the nanocomposite-modified glassy carbon electrode (GCE) and applied to construct a sensor. The immobilized GOD showed a pair of well-defined redox peaks and high catalytic activity for the oxidation of glucose.

A large number of one‐dimensional bundles of ZnSe nanowires with diameters ranging from 15–20 nm and lengths of up to tens of micrometers have been prepared via the thermal treatment of a ribbon‐like precursor (ZnSe·3ethylenediamine), which has been synthesized by a mixed solvothermal route, in an argon atmosphere. The as‐obtained precursor has been characterized by powder X‐ray diffraction (XRD), transmission electron microscopy (TEM), IR spectroscopy, thermogravimetric analysis, and elemental analysis. XRD and high‐resolution TEM characterization reveal that the as‐synthesized ZnSe nanowires have the single‐crystal hexagonal wurtzite structure with the [001] growth direction. The surface chemical composition of ZnSe nanowires has been studied by X‐ray photoelectron spectroscopy. The cooperative action of the mixed solvents may be responsible for the formation of the morphology of the resulting products. Room‐temperature photoluminescence measurements indicate the as‐grown ZnSe nanostructures have a strong emission peak centered at 587 nm and two weak emission peaks centered at 435 and 462 nm. The strong emission from the ZnSe nanostructures reveals their potential as building blocks for optoelectronic devices.

Focused metabolic profiling is a powerful tool for the determination of biomarkers. Here, a more global proton nuclear magnetic resonance ((1)H NMR)-based metabolomic approach coupled with a relative simple ultra high performance liquid chromatography (UHPLC)-based focused metabolomic approach was developed and compared to characterize the systemic metabolic disturbances underlying esophageal cancer (EC) and identify possible early biomarkers for clinical prognosis. Serum metabolic profiling of patients with EC (n=25) and healthy controls (n=25) was performed by using both (1)H NMR and UHPLC, and metabolite identification was achieved by multivariate statistical analysis. Using orthogonal projection to least squares discriminant analysis (OPLS-DA), we could distinguish EC patients from healthy controls. The predictive power of the model derived from the UHPLC-based focused metabolomics performed better in both sensitivity and specificity than the results from the NMR-based metabolomics, suggesting that the focused metabolomic technique may be of advantage in the future for the determination of biomarkers. Moreover, focused metabolic profiling is highly simple, accurate and specific, and should prove equally valuable in metabolomic research applications. A total of nineteen significantly altered metabolites were identified as the potential disease associated biomarkers. Significant changes in lipid metabolism, amino acid metabolism, glycolysis, ketogenesis, tricarboxylic acid (TCA) cycle and energy metabolism were observed in EC patients compared with the healthy controls. These results demonstrated that metabolic profiling of serum could be useful as a screening tool for early EC diagnosis and prognosis, and might enhance our understanding of the mechanisms involved in the tumor progression.

The discovery of efficient sources of terahertz radiation has been exploited in imaging applications, and developing a nanoscale terahertz source could lead to additional applications. High-frequency mechanical vibrations of charged nanostructures can lead to radiative emission, and vibrations at frequencies of hundreds of kilohertz have been observed from a ZnO nanobelt under the influence of an alternating electric field. Here, we observe mechanical resonance and radiative emission at ∼ 0.36 THz from core-shell ZnO mesocrystal microspheres excited by a continuous green-wavelength laser. We find that ∼ 0.016% of the incident power is converted into terahertz radiation, which corresponds to a quantum efficiency of ∼ 33%, making the ZnO microspheres competitive with existing terahertz-emitting materials. The mechanical resonance and radiation stem from the coherent photo-induced vibration of the hexagonal ZnO nanoplates that make up the microsphere shells. The ZnO microspheres are formed by means of a nonclassical, self-organized crystallization process, and represent a straightforward route to terahertz radiation at the nanoscale.

Monoclinic Y 2 (WO 4 ) 3 :Eu with three-dimensional hierarchical architectures were successfully synthesized by a hydrothermal method in ligand-free and chelating ligand-mediated processes, respectively. Microflowers assembled from two-dimensional nanoflakes were obtained in a surfactant-and template-free process, whereas microspheres with dandelion-like appearance assembled from one-dimensional nanoplates were observed upon the introduction of the appropriate amount of ethylenediamine tetraacetic acid (EDTA) to the precursor. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), energy-dispersive spectra (EDS), and photoluminescence (PL) spectroscopy were employed to characterize the as-obtained products. It was found that the amount of ligand agent, reaction temperature and time, and type of organic additive have crucial influences on the morphology of the resulting microstructures. The possible formation mechanisms for different microstructures were put forward. The addition of EDTA significantly changed the reaction pathway due to the excellent chelating and capping ability of EDTA. A detailed investigation on the photoluminescence of Y 2 (WO 4 ) 3 :Eu samples with flower-like, dandelion-like, and spindle microstructures indicates that the optical properties of these phosphors are strongly dependent on the morphology and size. The dandelion-like structure exhibits the strongest red emission with high color purity.