room temperature. The products were examined using an X-ray diffractometer (RINT 2200HF) and a scanning electron microscope (JSM -6700F). The products were dispersed onto copper grids with an amorphous carbon film and further characterized structurally and chemically by using a high-resolution transmission electron microscope (JEM-3000F) fitted with an X-ray energy dispersive spectrometer. The photoluminescence spectra were recorded at room temperature using a He±Cd laser as an excitation source at a wavelength of 325 nm.

Magnetic luminescent nanocomposites were prepared via a layer-by-layer (LbL) assembly approach. The Fe3O4 magnetic nanoparticles of 8.5 nm were used as a template for the deposition of the CdTe quantum dots (QDs)/polyelectrolyte (PE) multilayers. The number of polyelectrolyte multilayers separating the nanoparticle layers and the number of QDs/polyelectrolyte deposition cycles were varied to obtain two kinds of magnetic luminescent nanocomposites, Fe3O4/PE n /CdTe and Fe3O4/(PE3/CdTe) n , respectively. The assembly processes were monitored through microelectrophoresis and UV−vis spectra. The topography and the size of the nanocomposites were studied by transmission electron microscopy. The LbL technique for fabricating magnetic luminescent nanocomposites has some advantages to tune their properties. It was found that the selection of a certain number of the inserted polyelectrolyte interlayers and the CdTe QDs loading on the nanocomposites could optimize the photoluminescence properties of the nanocomposites. Furthermore, the nanocomposites could be easily separated and collected in an external magnetic field. It provides a novel technological innovation for luminescent tagging applications in biomedicine and biotechnology, such as rapid, convenient separation in vitro or site-specific transport in vivo due to the excellent magnetic properties of the nanocomposites.

DAST nanocrystal dispersion having fixed anisotropy may be enhanced by orientational factors. ExperimentalDAST, lauryl acrylate, and tricyclo[5.2.1.0 2,6 ]decane-4,8-dimethanol diacrylate (TD) were purchased from Aldrich Co. Inc. n-Dodecyltrimethylammonium chloride (DTMAC) and benzoin isopropyl ether (BIPE) were purchased from Tokyo Kasei Co., Ltd. DAST and BIPE were recrystallized twice from methanol and toluene, respectively. The other reagents were used without further purification. An ethanol solution (50 lL) containing DAST (5 mM) and DTMAC (5 mM) was injected into lauryl acrylate (5 mL) containing BIPE (0.1 M) and TD (1 wt.-%) according to the reprecipitation method [2]. The average nanocrystal size was obtained using a DLS-7000 dynamic light scattering analyzer (Otsuka Electronics); the viscosity and refractive index of the dispersion were 4.0 mPa s at 25 C and 1.444 at 20 C, respectively. A sample was positioned between the two poles of an electromagnet (Fluxdial precision electromagnet control system, Applied Magnetics Laboratory Inc.), which can operate at magnetic flux densities of up to 2.5 T, and the absorption spectra of the DAST nanocrystals dispersed in lauryl acrylate solution were measured in both the Faraday and Voigt configurations using a personal computer, the electromagnet, the detectable light from a Xe lamp light source (passed through a polarizer), a JASCO CT-25C monochromator, and a 2023 photodiode detector (New Forcus Inc.). After nitrogen gas had been bubbled through the DAST nanocrystal acrylate dispersion for 20 min, photocuring was performed in the magnetic field by irradiating the sample with UV light from a 500 W high-pressure mercury lamp (UI-501C, USHIO). To fix the anisotropic orientation of the DAST nanocrystal dispersion, we used a superconducting magnet (S15/17/40RT/13 horizontal magnet system, Oxford) having an output of up to 17 T. The optical rotatory dispersion spectra were measured using a JASCO J-820 spectropolarimeter.

The synthesis of water-soluble Mn doped ZnS nanocrystals with MPA (3-mercaptopropionic acid) as stabilizer is described. The coordination of Zn ion with MPA helps efficient doping of Mn and thus makes the process reproducible as compared to the common co-precipitation method. To obtain a high luminescent intensity, post-preparative treatments are performed. It is found that the surface states of the nanocrystals, such as the adsorption of oxygen and the coordination of MPA, play important roles in the enhancement of the luminescent intensity.

Plasma-enhanced chemical vapor deposition (PECVD) was used in the preparation of a series of bicomponent TiO2/SnO2 particulate films. The photocatalytic activities of the films are evaluated by photodegradation of phenol in solution. When both the TiO2 and SnO2 components of the bicomponent TiO2/SnO2 catalysts are accessible to reactants at the catalyst surface, photocatalytic degradation efficiencies are improved as compared to those obtained with TiO2 films. When this condition prevails, the two components are believed to act in a cooperative manner by increasing the degree of charge carrier separation sufficient to reduce recombination, while simultaneously allowing sufficient time for photoelectrons and photoholes on the catalyst surface to form reaction intermediates (for example, the superoxide radical ion, O2 ·-, formed by reaction of O2 with photoelectrons, and the phenol radical, formed by reaction of phenol with photoholes or OH· radicals) which cooperatively participate in later stages of the degradation process.

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tional energy at the T site is 145 meV in the present calculation and 152 meV in the zeroth-order approximation. The energy at the 0 site is 43 meV in the present calculation and 86 meV in the zeroth-order approximation. By the inelastic neutron scattering measurements the vibrational energy of hydrogen in the bulk a-zirconium at 873 K was obtained to be 144 meV, and the energy spread (fwhm of the peak) is 47 meVn2' It has been found that the calculated vibrational energy at the T site is in good agreement with the experiment. Garrett measured the vibrational energy of hydrogen on Ti(0001) surface by using high-resolution electron energy loss spectroscopy (HREELS).2S The vibrational energy of H and D is reported to be 120 and 85 meV, respectively. This value is greater than that calculated for hydrogen on zirconium surface. We cannot differentiate that this is due to the difference between Ti and Zr or the uncertainty of this calculation. (25) Garrett, S. J.; Egdell, R. G.; Riviere, J. C. J . Electron Spectrosc.Stable nanoparticulate a-Fe203stearate (Fe203-St) monolayers can be obtained by using nanoparticulate a-Fe203 (diameter 70 A) as the subphase. The area extrapolated to r = 0 is 27 A2 per hydrocarbon chain of the monolayer. The "collapse" pressure is about 28 dynlcm. The transfer ratio is 1.0 f 0.1 (this is a constant within the limit of experiment). The long spacing of the multilayer determined by X-ray diffraction is 160 A. The tilt angle of the hydrocarbon chains revealed by IR is 31° f 5 O . The long CH2 sequence of the hydrocarbon chains of the multilayer is in a trans planar structure. The surface coverage by Fez03 nanoparticles is very large (more than 90%). Stearic acid is converted to stearate ion almost completely and chemical bonds were formed between Fez03 and stearate ions. The particles in the polar plane of the multilayer are close packed in a hexagonal close packed (hcp) bilayer structure. The total thickness of the multilayer can be several thousand angstroms or more. The absorption and transmission properties of isolated nanoparticulate Fe203 hydrosol were maintained. Thus the multilayer can be regarded as a three-dimensional superlattice of quantum size particles.