Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
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…
The formation and evolution of the gap states formed with increasing Cs concentration in thin sexiphenyl (6P) films is followed with ultraviolet photoemission spectroscopy (UPS). Two distinct doping regimes are apparent, experimental considerations suggest that in the lower-doping bipolaron-like (dianionic 6P 2- ) sta…
Quasielastic neutron scattering experiments have been carried out to study the thermally activated rotational process of the NH4+ ion in the perovskite family NH4MF3 (M=Mg, Zn, Mn and Cd). The activation energies of this process in the high- and low-temperature structural phases have been obtained, and range from 44.8…
The optical absorption spectrum of NiO is measured at low temperatures and energies between 7000 and 30000 cm -1 . An assignment to cubic crystal field components of the 3d 8 configuration of Ni 2+ is proposed. The fine structure of the A band, showing two sharp lines at the lowest energies, 7811 and 7852 cm -1 , is e…
Upconversion luminescence of Er3+ in the chloride glass system has been investigated in ZnCl2-BaCl2-KCl-ErCl3 and CdCl2-BaCl2-KCl-ErCl3 glasses. Under 800 nm excitation, the glasses gave upconversion luminescence with barely detectable red (around 660 nm), very intense green (around 525–560 nm), and considerably inten…
Freely-suspended films of smectic liquid crystals can be regarded as membranes consisting of a stack of an integral number of molecular (smectic) layers with the layer planes being parallel to the two free surfaces. Because of their variable thickness (between thousands and only two layers) and the large variety of ph…
Magnesium grain boundary diffusion rates in forsterite aggregates have been experimentally determined from 1000° to 1300°C and 0.1 MPa to 10 GPa. The samples are fine‐grained (mean linear intercept of 4.3 μm) hot‐pressed aggregates. The technique employs a 26 Mg‐enriched surface layer and depth profiling using an ion…