[Photoluminescence of Silicon Nitride-Based ZnO Thin Film Developed with RF Magnetron Sputtering].

Owing to its merits of high corrosion resistance, high temperature stability as well as good mechanical strength etc., silicon nitride membrane (SiN) has been widely used as the experimental carrier of transmission electron microscope (TEM), scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-Ray spectroscopy (EDX) and other characterization. In particular, SiN can be used as a low disturbing background for SEM observation. However, the poor luminescent property of SiN thin film has restricted its wide application in fluorescent devices. In order to enhance the fluorescence efficiency of silicon nitride membrane, a series of ZnO films were prepared on a SiNx film substrate with radio frequency magnetron sputtering (RF magnetron sputtering) technology during the experiment. Samples were then non-situ and in-situ annealed in nitrogen atmosphere, respectively. Then, atomic force microscope (AFM), scanning electron microscopy (SEM) and Raman spectroscopy (Raman) were applied to study the microstructure and photoluminescence (PL) properties of the prepared films. This paper also systemically studies the luminescence of the prepared thin films. The results show that, luminescent intensity increases after sputtering, while annealing further promoted the grain growth, a substantial increase in crystallization behavior and a decrease in grain boundary. The microstructure and luminescence properties of ZnO/SiN thin films prepared by RF magnetron sputtering were significantly influenced by annealing method. Compared with the SiNx film, near the band edge of the intrinsic emission intensity (about 380 nm) of untempered ZnO/SiNx films and N(2) atmosphere ex-situ annealed ZnO/SiNx films were increased by more than 7.7 times and 34.0 times. Compared with non-situ annealed films, in-situ annealed films contained more oxygen vacancy defects, thus showing a stronger visible light PL intensity. In-situ annealed films exhibited a higher photoluminescence capacity during the wavelength from 425 to 600 nm of visible light. These results can help to optimize the preparation parameters of silicon nitride based ZnO fluorescent films.

[Study on Photocatalytic Performance of LaPO4 Nanorods with Different Crystal Phases].

Rare earth phosphate has a wide application in optical materials, laser materials and many fields with great development prospects. In this paper, LaPO4 nanorods with different crystalline phases are prepared with hydrothermal method, its photocatalytic performance are discussed, as well as the structure and UV diffuse reflectance spectroscopy. The research indicates that the hydrothermal temperature plays a key role in the crystal phase, while it is hexagonal at 120 ℃, monoclinic at 180 ℃ and the mixed phase at 160 ℃. The UV absorption has no obvious change of each crystalline phase, and they all show nanorods. The photocatalytic activity of LaPO4 for the degradation of MB is studied; it is found that the monoclinic LaPO4 has the best photocatalytic activity. Furthermore, monoclinic LaPO4 could decrease the fluorescence quantum efficiency and increase the separation efficiency of electrons and holes, which improve the photocatalytic activity. Besides, the main active species are confirmed to be hydroxyl radicals with capture experiments during the photocatalytic process.

[Standard sample preparation method for quick determination of trace elements in plastic].

Reference sample was prepared by masterbatch method, containing heavy metals with known concentration of electronic information products (plastic), the repeatability and precision were determined, and reference sample preparation procedures were established. X-Ray fluorescence spectroscopy (XRF) analysis method was used to determine the repeatability and uncertainty in the analysis of the sample of heavy metals and bromine element. The working curve and the metrical methods for the reference sample were carried out. The results showed that the use of the method in the 200-2000 mg x kg(-1) concentration range for Hg, Pb, Cr and Br elements, and in the 20-200 mg x kg(-1) range for Cd elements, exhibited a very good linear relationship, and the repeatability of analysis methods for six times is good. In testing the circuit board ICB288G and ICB288 from the Mitsubishi Heavy Industry Company, results agreed with the recommended values.

[The research on IR and TEM of polybutylcyanoacrylate nanoparticles].

Through latex polymerization with stabilizer (Dextran, low fraction), we prepared polybutylcyanoacrylate nanoparticles with a size of approximately 200 nm. The nanoparticle diameter decreases with decreasing stabilizer concentration. Using TEM and IR we studied the combination state and the mechanism between polybutylcyanoacrylate and Dextran. It was shown that each Dextran molecule could therefore contain several cyanoacrylate polymer moieties covalently linked via any of the available Dextran hydroxyl groups. Anchoring of the cyanoacrylate groups within the nanoparticle matrix would therefore result in an irreversible attachment between the Dextran and the nanoparticle. In this way, Dextran could be incorporated throughout the particle matrix as well as on the surface, producing the biodegradable particle. The results have been interpreted by reference to the accepted theories of steric stabilization and dispersion polymerization, and a model is proposed for the nanoparticle formation in the presence of Dextran.

[Raman spectrum research on structure and performance of nanometer TiO2 film photocatalyst supported on stainless steel netweb].

Crystal structure, particle size and thickness of film titania as photocatalyst on stainless steel netweb synthesized by sol-gel was studied by Raman spectroscopy. It was showed that diffusion of Fe in the base was banned when certain thickness of the film was obtained; when the film was calcined at 400 degrees C, it was anatase, and when the calcining temperature exceeded 400 degrees C, rutile came up in the film. The characteristic Raman peak of anatase shifted, which showed that the particle size of the film was changing, and from calculating, the size was about 10.7 nm. TEM result was consistent with it.

Chemiluminescence determination of chlorinated volatile organic compounds by conversion on nanometer TiO2.

A novel method based on conversion of chlorinated volatile organic compounds (CVOCs) to chlorine using a new type of column packed with nanometer TiO2 coupled with chemiluminescence (CL) has been developed for determination of them in workplace air. CVOCs are converted to chlorine by nanometer TiO2 at 220 degrees C. The Cl2 that is produced is selectively enriched on the column and subsequently released from the column at 600 degrees C. The Cl2 that is released is determined using a postcolumn CL detector. The CL intensity was linear with CCl4 in the range of 0.1-380 ppm, and the detection limit was 40 ppb (S/N = 3). Higher sensitivity could be acquired by using a larger volume of enrichment A similar procedure could be used for the determination of other CVOCs. CL intensities of CH2Cl2, CHCl3, and CCl4 at the same concentration increased in the order CH2Cl2 < CHCl3 < CCl4. The method has been successfully applied to the determination of CCl4 in workplace air, where 0.15-150 ppm CCl4 would be detected. The possible mechanism for the long lifetime of the column packed with nanometer TiO2 was tested using Raman spectrometer, X-ray powder diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The results showed that the column packed with nanometer TiO2 could be operated in the reversible mode for determination of CVOCs under the present conditions. The method would be potentially applied to the analysis of other chlorinated compounds in environment, such as persistent organic pollutants.