Materials Literature
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ABSTRACT Biodegradable films were prepared from rice bran, and their water vapor and oxygen permeabilities, mechanical properties and solubilities were studied. No differences in apparent water vapor permeability (WVP app ) were observed between rice bran films cast at pH 9.5 (RBfilm 9.5) and those cast at pH 3.0 (RBf…
A series of mesoporous titanosilicate TiMCM-41 molecular sieves with variable amounts of framework titanium have been hydrothermally synthesized using H 2 O 2 as a phase stabilizer. Some structurally analogous materials containing framework zirconium (ZrMCM-41), aluminum (AlMCM-41), or only silicon (MCM-41) have also…
Donor−acceptor systems where the rate of radiationless electronic energy transfer is influenced by the electronic structure of the intervening medium are studied. In this paper we report the observation of mediated energy transfer in a series of geometrically well-defined porphyrin dimers. The dimers consist of a free…
Lead zirconate titanate based composites containing silver particles were fabricated from commercially available PZT and Ag 2 O powder mixtures. Densification behavior and mechanical and dielectric properties were evaluated as a function of the volume fraction of silver. No unwanted reaction phases between the PZT mat…
A novel family of photo‐and electroactive amorphous molecular materials containing an oligothiophene moiety linked to two triphenylamine moieties has been designed and synthesized (see Figure). Their glass‐forming properties, morphological changes, and molecualr and solid‐state properties are described. They are repor…
Conformations of neutral and charged brushes on spheres have been explored for diblock and triblock copolymers adsorbed on colloidal particles and associated in micelles. The variation of layer thickness L with adsorbed amount for a wide range of core radii R (0.04 < L / R < 20) agrees well with the blob model of Daou…
A conceptually simple real-space convolution method has been developed which can be used to detect or enhance structural features in experimental macromolecular electron-density maps. The method has been implemented in a computer program (ESSENS). One application of the method is in selectively visualizing secondary-s…
In this article neutron-scattering experiments using the backscattering instrument IN13 on the glass-forming polymer polybutadiene are reported. As compared to other neutron spectrometers IN13 has a large range of wave vectors Q accessible. Therefore, a better statement can be made about the spatial extent of the obse…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSynthesis of Model 3-Miktoarm Star Terpolymers of Styrene, Isoprene, and Methyl MethacrylateStella Sioula, Yiannis Tselikas, and Nikos HadjichristidisView Author Information Department of Chemistry, University of Athens, Panepistimi…
The Dawson-type P(2)W(15)Nb(3)O(62)(9)(-) polyoxoanion-supported Re(CO)(3)(+) complex, [Re(CO)(3).P(2)W(15)Nb(3)O(62)](8)(-) (1), has been synthesized and characterized in two different counter-cation compositions. The [(n-C(4)H(9))(4)N](8)(8+) complex provides a highly soluble compound which exists as a single isomer…
The preparation and purification of the heterocyclic diradical benzo-1,2:4,5-bis(1,3,2-dithiazolyl) (BBDTA) is described. Crystals of BBDTA, grown by fractional sublimation at 120−180 °C/10 -3 Torr, are monoclinic, space group P 2 1 / c, with a = 4.144(2), b = 9.0344(13), and c = 10.7424(16) Å, β = 91.11(3)°, and Z =…
The magnetic couplings in insulating ${\mathrm{LaMnO}}_{3}$, ${\mathrm{CaMnO}}_{3}$, and the planar analogs ${\mathrm{La}}_{\mathrm{n}+1}$${\mathrm{Mn}}_{\mathrm{n}}$${\mathrm{O}}_{3\mathrm{n}+1}$ are estimated using standard superexchange arguments. The orbital ordering observed in ${\mathrm{LaMnO}}_{3}$ is found to…
As in the case of uracil, a complete set of vibrational spectra of thymine and its N-deuterated species, obtained from several spectroscopic techniques, i.e., neutron inelastic scattering (NIS), Raman scattering, and infrared absorption (IR), has been used in order to assign the vibrational modes on the basis of an ab…
With age, the proximal sections of turkey leg tendons become calcified, and this phenomenon has led to their use as a model for collagen mineralization. Mineralizing turkey leg tendon was used in this study to characterize further the composition and cross-linking of collagen in calcified tissues. The cross-link profi…
Conformational analysis of highly substituted porphyrins has potential implications for modeling the behavior of macrocycles in tetrapyrrole-containing protein complexes and during catalytic reactions. In order to study the influence of different substituent patterns on the conformation of the porphyrin macrocycle, a…
The analysis of multilayered interference coatings by coupled-mode theory is considered to be an approximation useful for small index, gain, and/or loss modulations. In this paper, we show that an exact analysis of a multilayer coating with coupled-mode theory is possible by redefining the coupling and detuning coeffi…
We studied the glass transition dynamics of polystyrene micronetwork colloids with an average cross-link density of 1:50 (inverse number of monomer units between cross-links) and a hydrodynamic radius of about 100 nm by dynamic light scattering. Special emphasis was put on extracting correct intermediate scattering fu…
The flow properties of aqueous suspensions of silica particles with diameters ranging from 117 to 780 nm were measured as a function of volume fraction, ionic strength, and continuous phase composition. Dense, aqueous suspensions of all sizes displayed similar behavior with a yield stress in the limit of low shear rat…
We have calculated the electronic structures of five different manganese-oxo dimer complexes using density functional methods combined with the broken symmetry and spin projection concepts. The number of carboxylate, oxo, and peroxo bridging ligands was varied, and the terminal ligands were triazacyclononane (TACN). T…
Globular proteins can be crystallized by the addition of electrolyte or nonadsorbing polymer. Too much additive, however, gives rise to amorphous precipitates. By comparing existing data on various proteins with previous work on a model colloid-polymer mixture, we suggest an explanation for noncrystallization in terms…