Hydrothermal synthesis of core-shell structured PS@GdPO<Subscript>4</Subscript>:Tb<Superscript>3+</Superscript>/Ce<Superscript>3+</Superscript> spherical particles and their luminescence properties

Non-aggregated spherical polystyrene (PS) particles were coated with GdPO₄:Tb³⁺/Ce³⁺ phosphor layers by a conventional hydrothermal synthesis using poly(vinylpyrrolidone) (PVP) as an additive without further annealing treatment. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL), as well as luminescence decay experiments were used to characterise the resulting core-shell structured PS@GdPO₄:Tb³⁺/Ce³⁺ samples. The results of XRD indicated that the PS particles were successfully coated with the GdPO₄:Tb³⁺/Ce³⁺ phosphor layers, which could be further verified by the images of FESEM. Under ultraviolet excitation, the PS@GdPO₄:Tb³⁺/Ce³⁺ phosphors show Tb³⁺ characteristic emission, i.e. ⁵D₄-⁷F_J (J = {6, 5, 4, 3}) emission lines with green emission ⁵D₄-⁷F₅ (543 nm) as the most prominent group. The core-shell phosphors so obtained have potential applications in field emission display (FED) and plasma display panels (PDP).     

Controllable photoluminescence properties of an anion-dye-intercalated layered double hydroxide by adjusting the confined environment

This article reports a novel method to tune the photoluminance properties of ammonium 1-anilinonaphthalene-8-sulfonate (ANS) in a 2D matrix of layered double hydroxide (LDH) by changing the interlayer microenvironment. ANS and a series of surfactants with different alkyl chain lengths (pentanesulphonate (PES), hexanesulphonate (HES), heptanesulphonate (HPS), decanesulphonate (DES), and dodecylsulphonate (DDS)) were respectively cointercalated into the galleries of ZnAl-LDH by the anion exchange method. Thin films of ANS/surfactant-LDHs obtained by the solvent evaporation method possess good c orientation as revealed by XRD and SEM. It was found that the ANS/HPS-LDH film showed the maximum fluorescence efficiency and the longest intensity-average lifetime among these ANS/surfactant-LDH composites owing to the "size-matching" rule between the organic dye and surfactant. Moreover, the fluorescence properties can be tuned by changing the relative molar ratio of ANS/HPS, and the film containing 20% ANS (molar percentage, expressed as ANS(20%)/HPS-LDH) exhibits the maximum fluorescence efficiency, the longest average lifetime, and significantly enhanced photo and thermal stability. In addition, the composite films show fluorescence anisotropy, attributed to the preferential orientation of ANS in the LDH gallery. Therefore, this work demonstrates a feasible approach to tuning the photoluminescence properties of a dye confined in an inorganic 2D matrix via changing the interlayer microenvironment, which may be considered to be a good candidate for solid photoluminescence materials, nonlinear optics, and polarized luminescence materials.     

Improvement of antifungal activity of carboxin by inclusion complexation with cucurbit[8]uril

Interaction between cucurbit[8]uril (Q[8]) with a fungicide, carboxin in aqueous solution, was investigated by ¹H-NMR, electronic absorption spectroscopy, and fluorescence spectroscopy. Spectroscopy analysis established a basic interaction model which formed an inclusion complex with a host:guest ratio of 1:1. ¹H-NMR showed that Q[8] encapsulated the phenyl ring into its cavity and the rest of the guest molecule stayed outside the host. Comparative in vitro evaluations of the growth inhibitory effects of the inclusion complex solution toward Rhizoctonia solani demonstrated appreciable improvements in the antifungal activity of carboxin through the addition of Q[8]. In comparison with the positive control, improvement was evaluated in terms of area covered by the mycelia of R. solani and their growth inhibition rate. Inclusion complexation of carboxin with Q[8] suggests a potential means for production of an environmentally friendly carboxin-based fungicide to counteract R. solani.     

Determination of explosives based on novel type of sensor using porphyrin functionalized carbon nanotubes

The hydroxide of meso-tetraphenylporphyrin derivatives functionalized carbon nanotubes (CNTs) was fabricated in our research to explore the interaction between porphyrin and explosive. It was turned out that in the formation of grid porphyrin film, carbon nanotubes as a cruciul base materials promoted the electron transfer rate. Most of important, the results also showed that the electrochemical response was enhanced through increasing the number of -OH substitution in porphyrin. Such information provides the platform for a practical strategy for rational design of the sensor of explosives.     

One‐step electrodeposition of amorphous carbon films containing WO3 with high conductivity and good wettability

Tungsten trioxide‐incorporated hydrogenated amorphous carbon (WO₃/a‐C:H) films have been fabricated on a single‐crystal silicon wafer by liquid phase electrodeposition using methanol as carbon source and tungsten carbonyl as incorporated reagent. The morphology, composition and structure of the films have been investigated by SEM, XPS, Raman scattering spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscope (TEM), respectively. The effects of WO₃ incorporation on the electrical and wetting properties were studied in detail. The characterization results showed that tungsten trioxide nanocrystalline particles with diameters in the range of 10–20 nm were homogenously embedded in the amorphous carbon films. Also, the electrical conductivity and wetting ability of the films were strongly improved due to the contribution of the tungsten trioxide. Copyright © 2010 John Wiley & Sons, Ltd.     

One-dimensional GdVO4:Ln (Ln=Eu, Dy, Sm) nanofibers: Electrospinning preparation and luminescence properties

One-dimensional GdVO₄:Ln³⁺ (Ln=Eu, Dy, Sm) nanofibers have been prepared by a combination method of sol-gel process and electrospinning technology. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL), quantum efficiency (QE), and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples. The XRD, FT-IR, and TG-DTA results show that GdVO₄:Ln³⁺ nanofibers samples crystallize at 700 °C. SEM images indicate that the as prepared precursor fibers are smooth. After being calcined at 700 °C for 4 h, the fibers still maintain their fiberlike morphology with rough surface. TEM image further manifests that the GdVO₄:Ln³⁺ nanofibers consist of nanoparticles. Under ultraviolet excitation and low-voltage electron beam excitation, GdVO₄:Ln³⁺ phosphors showed their strong characteristic emission due to an efficient energy transfer from vanadate groups to dopants. The optimum doping concentration of Ln³⁺ in the GdVO₄ nanofibers also has been investigated.     

Novel chemiluminescent assay for staphylococcal enterotoxin B

An enzyme-linked immunosorbent assay, a horseradish peroxidase-catalyzed fluorogenic reaction, and chemiluminescence (CL) analysis have been combined to develop a sandwich ELISA for Staphylococcal enterotoxin B (SEB) using monoclonal antibodies for different epitopes of SEB. The enzyme catalyzed reaction of 3-(4-hydroxyphenyl propionate) with the urea complex of hydrogen peroxide produced a fluorescent dimer which was detected by chemiluminescence analysis. The CL response to SEB is linear in the range from 6.0 to 564?pg?mL^?1 (r?=?0.9993), and the detection limit is 3.3?pg?mL^?1 (S/N?=?3). Intra- and interassay coefficients of variation are <7.0% at three concentrations (24, 96 and 384?pg?mL^?1). The method was applied to the analysis of SEB in serum, lake water and milk samples. The results compared well with those obtained by conventional ELISAs.

(±)-Glovanon和(±)-5-O-Methylglovanon的首次全合成及其抑菌活性研究

以廉价的异香草醛和2,4,6-三羟基苯乙酮为起始原料,经过C-异戊烯基化、选择性甲基化、甲氧甲基化、羟醛缩合、去保护基、催化环化以及脱除甲基等步骤,分别以13.3%和23%的总收率首次完成了天然异戊烯基黄烷酮Glovanon(1)和5-O-methylglovanon(2)的全合成.合成的关键步骤是2,4,6-三羟基苯乙酮的单C-异戊烯基化.所有新化合物的结构都经过1H NMR,IR,MS确认.抑菌活性研究表明,两种新合成的化合物对藤黄微球菌(M.luteus)和大肠杆菌(E.coli)均有良好的抑制作用.     

单斜BiVO4可见光催化降解甲基橙的形貌效应

以硝酸铋和偏钒酸铵为无机源,NaOH为pH值调节剂,三嵌段共聚物P123为表面活性剂,采用醇-水热法制备了多种形貌的单斜BiVO4.利用X射线衍射、N2吸脱附、扫描电子显微镜、X射线光电子能谱和紫外可见光漫反射等技术表征了其物化性质,并考察了这些BiVO4样品在可见光照射下降解甲基橙的催化活性.结果表明,表面活性剂和溶...