Materials Literature
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The Stark effect on the electronic absorption spectrum of CdSe nanocrystals has been studied for nanocrystals ranging in size from 80 to 20 Å in diameter. For all but the smallest clusters, a second derivative line shape is observed, indicative of a dipole moment in the excited state. This result is independent of the…
The densification behavior, microstructure, and electrical properties of ZnO-V2O5 ceramics were studied with V2O5 as the only additive ranging from 0.01 to 1.0 mol %. The addition of V2O5 to zinc oxide shows a tendency to enhance the densification rate and promote grain growth. However, a microstructure that consisted…
Abnormal (100) grain growth has been characterized in predominantly (111)-textured Cu thin films as a function of deposition temperature, annealing temperature and the presence of a Ta or W underlayer. For films deposited at room temperature, bimodal grain size distributions are observed at annealing temperatures at o…
A nonsaturable component to the 980 nm excited state absorption (ESA) is found in Er3+-doped silica glass fibers. This anomalous behavior of the ESA provides a way of quantitatively characterizing the degree of clustering in these glasses. It is found that the degree of clustering is greater for higher Er3+ concentrat…
Foam in porous media is a fascinating fluid both because of its unique microstructure and because of its dramatic influence on the flow of gas and liquid. A wealth of information is now compiled in the literature that describes. The literature contains conflicting views of the mechanisms of foam generation, destructio…
We have observed enormous shifts of the optical-absorption peak during the reduction of gold-sulfide particles (${\mathrm{Au}}_{2}$S) to gold particles. A two-step colloidal method is used for the nanoparticle synthesis. We can explain our findings by assuming the colloidal particles have a gold coating on the surface…
We demonstrate the feasibility of ab initio studies of piezoelectricity within an all-electron scheme. The focus of our analysis is on wurtzite ZnO; for comparison, some results are also presented for the related materials BeO and ZnS. The comparative study is performed in order to understand the microscopic origin of…
As most technologically important metals will form oxides readily, any complete study of adhesion at real metal surfaces must include the metal-oxide interface. The role of this ubiquitous oxide layer cannot be overlooked, as the adhesive properties of the oxide or oxide-metal system can be expected to differ profound…
We have investigated the light switching properties of polymer dispersed liquid crystal (PDLC) films, which can be characterized by the spectral change in transmittance and reflectance due to switching by application of a suitable electrical voltage. The PDLC samples were prepared using the standard liquid crystal mix…
An experimental study of positive corona discharge in air for wire-to-plane geometry is presented for small gaps (from 8 to 16 mm). The measurements carried out show that wire-to-plane positive corona behaviour deviates from the Townsend relation in the low-current limit near the onset. This deviation is attributed to…
The trillionfold concentration of sound energy by a trapped gas bubble, so as to emit picosecond flashes of ultraviolet light, is found to be extremely sensitive to doping with a noble gas. Increasing the noble gas content of a nitrogen bubble to about 1% dramatically stabilizes the bubble motion and increases the lig…
M 5 (PO 4 ) 3 X apatites are well known for their technological importance as phosphors, laser hosts and biocompatible materials. Divalent-europium-activated alkaline earth chloroapatites are of special importance for their application as the blue component in high-efficiency trichromatic fluorescent lamps. In these a…
A sol-gel method for the preparation of transparent copper nano particle-containing SiO<SUB>2</SUB> coatings on glass has been developed. The sol is synthesized from alkoxysilanes and tetra ethyl orthosilicate with copper ammine complexes, prepared from Cu<SUP>2+</SUP> salts and amino alkoxy silanes. Glass substrates…
The adhesion of sol-gel antireflective porous silica coatings on vitreous optical substrates has been dramatically improved by exposure to ammonia vapors or a dip in basic solutions. The approximately 70 to 270-nm thick coatings consisted of monolayers of spherical, 20-nm diameter amorphous silica particles deposited…
By using site-directed fluorescence spectroscopy, we have carried out structure/function studies on lactose permease purified from Escherichia coli in dodecyl beta, D-maltoside. Initially, permease containing a single native Cys at position 148 (helix V) was studied, since this residue is protected against alkylation…
Features of the Mass Spectrometric Investigation of Vaporization of Oxide Systems Vapours of Oxyacid Salts Oxide Film Deposition Vaporization of Refractory Components Vaporization of Oxide Materials in High Temperature Processing Vaporization of Oxide Glasses and Glass Forming Melts Ion/Molecule Reactions Vaporization…
Hydrolysis of GTP by a variety of guanine nucleotide-binding proteins is a crucial step for regulation of these biological switches. Mutations that impair the GTPase activity of certain heterotrimeric signal-transducing G proteins or of p21ras cause tumors in man. A conserved glutamic residue in the alpha subunit of G…
We extend the technique of fluorescence resonance energy transfer (FRET) by introducing a luminescent terbium chelate as a donor and an organic dye, tetramethylrhodamine, as an acceptor. The results are consistent with a Förster theory of energy transfer, provided the appropriate parameters are used. The use of lantha…
Interplanar interactions were analysed for metal bridged phthalocyanine dimers, [NBu4] [M(III)Pc2] (M = Y, Yb and Lu), by using zero field splitting (ZFS) parameters in the T1 states. The observed ZFS D and a triplet lifetime decreased remarkably due to dimerization. From a comparison of D between the monomer and the…
Abstract This work describes the effect of solvent precipitation on the crystallization behavior and morphology of nylon 6,6. We found that solvent precipitation of nylon 6,6 induces elevated crystallization temperatures upon cooling from the melt ( T mc ) and highly nucleated morphologies that rival those induced by…