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。
The optical properties of the heavy‐metal oxide glasses 70PbO . 30TiO 2 ,70PbO . 30CdO, and 70PbO . 30TeO 2 doped with Pr 3+ ,Nd 3+ ,and Eu 3+ ions have been investigated. The transition energies of the absorption spectra of Pr 3+ and Nd 3+ ions are analyzed for the Racah parameters, configuration interaction terms, a…
The kinetics of curing for a modified bismaleimide (BMI) has been investigated to ascertain a suitable cure model for the material. The experimental data for characterizing the curing kinetics for a modified bismaleimide resin were determined using a DSC isothermal scan method and indicated a curing mechanism involvin…
Mineralogical, chemical, and isotopic characteristics of clays from Ocean Drilling Program (ODP) sites 1035, 856, 1036, and 858, drilled in Middle Valley at the northern end of the Juan de Fuca Ridge during Legs 139 and 169, were studied using X-ray powder diffraction, differential thermal analysis, infrared spectrosc…
Medium-chain-length (mcl) poly(3-hydroxyalkanoates) (PHAs) are storage polymers that are produced from various substrates and accumulate in Pseudomonas strains belonging to rRNA homology group I. In experiments aimed at increasing PHA production in Pseudomonas strains, we generated an mcl PHA-overproducing mutant of P…
D-Glucose and 19 glucose derivatives were investigated by positive and negative ion matrix assisted laser desorption/ionization time-of-flight mass spectrometry using 2,5-dihydroxybenzoic acid (DHB) as the matrix. The set of substrates includes oligomers of amylose and cellulose, native alpha-, beta-, and gamma-cyclod…
A systematic study of the structural, magnetic and electrical properties of the manganites Pr1-x Sr x MnO3(0≤ x ≤ 0.5) has been carried out. X-ray diffraction investigation shows a structural change with composition, from orthorhombic (0 ≤ x ≤ 0.2) to rhombohedral (0.25 ≤ x ≤ 0.5). The magnetic properties of Pr1-x Sr…
We have performed a theoretical study of the atomic and electronic structure of the four compounds Sr2TiO4, Sr3Ti2O7, Sr4Ti3O10 and SrTiO3, by a total energy semiempirical Hartree-Fock method. We show that the intercalation of SrO3 layers in the perovskite structure of SrTiO3 induces lattice distortions modifications…
Porous microspheres of polyester–polyether block copolymer based on polycaprolactone/polylactide/poly(ethylene oxide) (PCEL) were prepared by an emulsification–solvent evaporation technique. The effect of hydrophilicity/hydrophobicity of the polymer on the morphology of the PCEL microspheres was studied and compared w…
The electro-optic and dielectric properties of organic–inorganic 2-amino-5-nitropyridium dihydrogen phosphate crystals were measured near room temperature at a wavelength of 632.8 nm and as a function of an electric-field frequency that varied from 1 kHz to 40 MHz. The frequency dispersion of the electro-optic coeffic…
We consider a general Fibonacci quasicrystal (FQC) in which both the masses and the elastic constants are aperiodically arranged. Making use of a suitable decimation scheme, inspired by real-space renormalization-group concepts, we obtain closed analytical expressions for the global transfer matrix and transmission co…
We report dc magnetization, M\"ossbauer spectroscopy, and x-ray-diffraction measurements on ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{V}}_{x}$ alloys, quenched or heat treated, with single phase bcc structure in the whole concetration range. It is well known that the saturation magnetization of these alloys decreases…
The atomic structure of iron phosphate glasses containing uranium has been studied by complementary neutron and x-ray scattering techniques. By combining x-ray and neutron structure factors, detailed information about different pair interactions has been obtained. Most of the basic structural features such as coordina…
Titanium porphyrin hydrazido complexes (TTP)Ti = NNR2 (TTP = meso-tetra-p-tolylporphyrinato dianion; R = Me (1), Ph (2)) were synthesized by treatment of (TTP)TiCl2 with 1,1-disubstituted hydrazines H2NNR2 (R = Me, Ph) in the presence of piperdine. The nucleophilic character of the hydrazido moiety was demonstrated in…
Thin films of poly(vinylcinnamate) and poly(7-methacryloyloxycoumarin) have been exposed to linearly polarized UV light. The resulting anisotropic films have been characterized by using UV, conventional and polarization modulation FTIR spectroscopies. In particular, several internal vibrational modes have been used as…
Reaction of trialkylaluminum Al2R6 (R = Me, Et) with 2,2′-methylenebis(6-tert-butyl-4-methylphenol) (mbmpH2) gives the dimeric mono(alkyl) complex [Al(mbmp)R]2 with bridging oxygen atoms. Reaction of [Al(mbmp)R]2 with one equiv. of 2-propanol results in the formation of the dimeric isopropoxide [Al(mbmp)(μ-OiPr)]2. Si…
Aqueous solutions of the calcium and sodium salts of dipicolinic acid (DPA) were shown to have weak fluorescence when excited at wavelengths near 300 nm, but no fluorescence was observed from DPA alone. Upon UV irradiation at 254 nm the fluorescence of all three forms increases dramatically. The emission spectrum of c…
The core structure of a screw dislocation in the diamond lattice has been calculated with the Stillinger-Weber potential for the interatomic interaction. The non-dissociated screw dislocation positioned at the centre of a unit hexagon normal to the dislocation line is a stable configuration A. A perfect screw centred…
A Landau expansion of the elastic energy in the strains is used to study two-dimensional structures in tetragonal-orthorhombic ferroelastics with constraints. Local energy minima are found with respect to the components of the displacement and so the strains satisfy the compatibility relation; this interdependence of…
The photoelectric characteristics (independent of ferroelectric polarization) of metal-ferroelectric-metal thin film structures upon exposure to radiation in different ranges of mercury arc lamp spectrum are studied for the Pb(Zr 0.5 2Ti 0.48 )O 3 ( PZT ) ferroelectrics. The PZT films on platinized silicon substrates…
Hydrogen permeation and corrosion inhibition characteristics of isomers of phenylenediamine, toluidine, and nitroaniline were studied on mild steel in 1M HCl. The Tafel extrapolation method was used to determine the inhibition efficiency, while the Devanathan–Stachurski technique was used to determine the hydrogen per…