Materials Literature
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Chemical imidization of polyamic acid based on 1,5-diaminonaphthalene and a dianhydride was studied by UV−visible and FT-IR ATR techniques under various reaction conditions, such as polyamic acid concentration, solvent condition (dry vs humidity-exposed NMP), catalysts of tertiary amines with different degrees of ster…
Raman spectroscopy was used to study strain-induced molecular stress in cold-drawn polyethylenes, which were being used as a model system for fibrils present in the crazes formed during environmental stress crack resistance (ESCR) tests. The molecular stress was measured at 240 K in order to minimize relaxation phenom…
The possibility that the structure of the novel semiconducting perovskite-related material strontium niobium oxide, Sr 5 Nb 5 O 17 , refined by Schmalle et al. [ Acta Cryst. (1995), C 51 , 1243–1246] in space group Pnn 2, might instead belong to space group Pnnm has been investigated following an analysis of the atomi…
The Unified Interaction Model (UNIM), developed to describe thermoluminescence dose response, is based on both radiation absorption stage and recombination stage mechanisms. The UNIM incorporates both the Track Interaction Model (TIM) for heavy charged particles (localised and highly nonuniform ionisation density dist…
This paper reports the near-infrared (NIR) surface-enhanced Raman scattering (SERS) detection of immune reaction on gold colloid particles without bound/free (B/F) antigen separation. A SERS spectrum was measured for anti-mouse IgG at 2.2×10-8 M adsorbed on gold colloid particles. The spectrum showed a number of Raman…
The various irreversible and reversible photoinduced phenomena in chalcogenide glasses, among them isotropic and anisotropic effects, were considered until now to have different origins. Upon reexamination, we find that the elemental photostructural steps are the same for all these phenomena. These are nonradiative re…
Abstract Novel guest-host liquid crystal systems containing 3,3-disubstituted azobenzenes as guests were prepared on the basis of molecular design by molecular calculations to achieve the improvement of compatibility of the chromophore with nematic phases. No phase change of nematic liquid crystals was induced by the…
71 Ga and 69 Ga single-crystal NMR spectra of a β-Ga 2 O 3 twin have been analyzed in terms of the 71 Ga/ 69 Ga quadrupole coupling and chemical shielding anisotropy (CSA) interactions. Analyses of the magnitudes and orientations of the interaction tensors for the two distinct crystallographic gallium sites in the two…
Type VIII collagen is a short chain collagen. Two chains have been described, alpha1(VIII) and alpha2(VIII), but the chain composition of type VIII collagen is far from resolved. To address this question, we have expressed full-length alpha1(VIII) and alpha2(VIII) chains in an in vitro translation system supplemented…
We have performed electron energy-loss spectroscopy analysis of polystyrene in the analytical transmission electron microscope in order to evaluate the possibility of obtaining both chemical and dielectric information on the polymer at the submicrometre scale. Irradiation has also been studied, particularly the influe…
The electrical conductivity of silicone rubber vulcanizates containing carbon blacks [e.g., acetylene black, lamp black, and ISAF (N-234) black] were investigated. The change in electrical conductivity with varying amounts of carbon blacks and the temperature dependence was measured. The mechanical properties like ten…
Electronic, vibrational and rotational contributions to the dipole moment μ, polarizability α, and first and second hyperpolarizabilities, β and γ, are presented for the boron hydride molecule; static and dynamic rovibrational properties are reported for the first time. The electronic contributions are computed ab ini…
Alternate feeding of glucose and propionic acid to phosphate-depleted batch cultures of Ralstonia eutropha (reclassified from Alcaligenes eutrophus ) produced poly(3-hydroxybutryate- co -3-hydroxyvalerate) [P(3HB- co -3HV)] with thermal properties markedly different from random copolymers of similar monomer content. T…
Discontinuous molecular dynamics simulations are used to study the structure and relaxation of large, off-lattice, near-perfect, tri- and tetrafunctional polymer networks at a packing fraction of 0.43. The networks are constructed by end-linking freely jointed, tangent hard-sphere chains ranging in length from N = 20…
A new route for the synthesis of conducting polypyrrole–silica composites is described. Silica gel particles were modified by aminopropyltriethoxysilane (APS) and acted as porous inorganic substrates for the in situ synthesis of polypyrrole (PPy). The resulting polypyrrole–silica–APS hybrid materials were characterize…
The state of Bi at the grain boundaries of ZnO varistors was analyzed using FE‐TEM with EDS point and mapping analysis with a spatial resolution of less than 1 nm. The continuous existence of Bi of less than 1/2 atomic layer has been confirmed at ZnO‐ZnO junctions without any secondary phase. The coexistence of a crys…
Changes in the structure and stoichiometry of the p-CdTe surface as a result of etching have been studied by high-resolution x-ray photoelectron spectroscopy and the Rutherford backscattering method. Etching with bromine-methanol and bromine-butanol solutions is shown to enrich the surface with elementary tellurium .…
Biochemical controls that regulate the biosynthesis of poly-3-hydroxybutyrate (PHB) were investigated in Rhizobium (Cicer) sp. strain CC 1192. This species is of interest for studying PHB synthesis because the polymer accumulates to a large extent in free-living cells but not in bacteroids during nitrogen-fixing symbi…
The time-dependent quasi-one-dimensional transport of electrons or holes along the molecular columns in columnar liquid crystals has been studied. Recent mobility measurements on the tryphenylene-based HAT-n materials have revealed Gaussian transits in the liquid crystalline phases but dispersion in the crystalline ph…
The chemical reactions occurring in the thermal treatment of bisphenol-A polycarbonate (PC) and poly(methyl methacrylate) (PMMA) blends have been investigated by nuclear magnetic resonance (NMR), mass spectrometry (MS), size exclusion chromatography (SEC), and thermogravimetry (TG). Our results suggest that in the mel…