Photocatalytically active gamma-WO3 films from the atmospheric pressure CVD of WOCl4 with ethyl acetate or ethanol

Communication: Coatings Of Yellow gamma-WO3 are deposited on glass by APCVD of WOCl4 and either ethanol or ethylacetate at 350-450degreesC. The yellow films show significant photoactivity for the destruction of stearic acid, and photoinduced superhydrophilicity. Preparation of blue reduced WO2.92 films from the same reaction at higher substrate temperatures of 500-600degreesC (Figure) is also found to be possible. These films show no photoactivity, but can be converted into the fully stoichiometric photoactive form simply by heating in air.

Novel TiO2 CVD films for semiconductor photocatalysis

A novel CVD film of titanium(IV) oxide has been prepared on glass, via the reaction of titanium(IV) chloride and ethyl acetate, using a CVD technique. The film is clear, very robust mechanically and comprised of a thin (24 nm) layer of nanocrystalline anatase titania that absorbs light of lambda

The VLT-FLAMES survey of massive stars: wind properties and evolution of hot massive stars in the Large Magellanic Cloud

We have studied the optical spectra of a sample of 28 O- and early B-type stars in the Large Magellanic Cloud, 22 of which are associated with the young star forming region N11. Our observations sample the central associations of LH9 and LH10, and the surrounding regions. Stellar parameters are determined using an automated fitting method ( Mokiem et al. 2005), which combines the stellar atmosphere code fastwind ( Puls et al. 2005) with the genetic algorithm based optimisation routine PIKAIA ( Charbonneau 1995). We derive an age of 7.0 +/- 1.0 and 3.0 +/- 1.0 Myr for LH9 and LH10, respectively. The age difference and relative distance of the associations are consistent with a sequential star formation scenario in which stellar activity in LH9 triggered the formation of LH10. Our sample contains four stars of spectral type O2. From helium and hydrogen line fitting we find the hottest three of these stars to be similar to 49- 54 kK ( compared to similar to 45- 46 kK for O3 stars). Detailed determination of the helium mass fraction reveals that the masses of helium enriched dwarfs and giants derived in our spectroscopic analysis are systematically lower than those implied by non-rotating evolutionary tracks. We interpret this as evidence for efficient rotationally enhanced mixing leading to the surfacing of primary helium and to an increase of the stellar luminosity. This result is consistent with findings for SMC stars by Mokiem et al. ( 2006). For bright giants and supergiants no such mass discrepancy is found; these stars therefore appear to follow tracks of modestly or non-rotating objects. The set of programme stars was sufficiently large to establish the mass loss rates of OB stars in this Z similar to 1/2 Z(circle dot) environment sufficiently accurate to allow for a quantitative comparison with similar objects in the Galaxy and the SMC. The mass loss properties are found to be intermediate to massive stars in the Galaxy and SMC. Comparing the derived modified wind momenta D-mom as a function of luminosity with predictions for LMC metallicities by Vink et al. ( 2001) yields good agreement in the entire luminosity range that was investigated, i.e. 5.0