Materials Literature
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Abstract Fourier transform infrared (FTIR) spectroscopy investigations in the near infrared (N1R) region of synthetic and natural kaolinites with various octahedral substitutions have been carried out in order to elucidate the relationships between the substituted cations and specific features of the NIR spectra. The…
Carbon‐supported platinum (Pt/C) with an adsorbed layer of underpotential deposited (upd) Sn is a much better catalyst for the methanol oxidation reaction (MOR) than a carbon‐supported platinum‐tin (PtSn/C) alloy. In situ X‐ray absorption (XAS) was used to determine the differences in the effects that the two methods…
Extruded bioplastic was prepared from cornstarch or poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate) (PHBV) or blends of cornstarch and PHBV. The blended formulations contained 30 or 50% starch in the presence or absence of polyethylene oxide (PEO), which enhances adherence of starch granules to PHBV. Degradation of…
Osteogenesis imperfecta (OI), a heritable disease caused by molecular defects in type I collagen, is characterized by skeletal deformities and brittle bones. The heterozygous and homozygous oim mice (oim/+ and oim/oim) exhibit mild and severe OI phenotypes, respectively, serving as controlled animal models of this dis…
Abstract This study examines the influence of minerals and amorphous phases associated with kaolin and kaolinitic rocks on kaolinite crystallinity indices (KCI) derived from X-ray diffraction (XRD) data in order to select the best index for systematic studies of commercial kaolins or geological sequences. For this pur…
We present ab initio calculations using density functional theory (DFT) within the local density approximation (LDA) on PbO in the α-phase and the idealized CsCl structure. The electron densities clearly show that CsCl-structured PbO has a symmetric lead site while α-PbO shows asymmetry, forming what could be describe…
A method of modelling the three-dimensional microstructure of random isotropic two-phase materials is proposed. The information required to implement the technique can be obtained from two-dimensional images of the microstructure. The reconstructed models share two-point correlation and chord-distribution functions wi…
On the basis of the pseudopotential plane-wave method and the local-density-functional theory, this paper studies energetics, stress-strain relation, stability, and ideal strength of $\ensuremath{\beta}$-SiC under various loading modes, where uniform uniaxial extension and tension and biaxial proportional extension ar…
We consider three mechanisms of hysteresis phenomena in alternating magnetic field: the domain-wall motion in a random medium, the nucleation, and the retardation of magnetization due to slow (critical) fluctuations. We construct a quantitative theory for all these processes. The hysteresis is characterized by two dyn…
High‐temperature oxidation of monolithic boron nitride (BN) is examined at 900–1200°C. Hot‐pressed BN and both low‐ and high‐density chemically vapor‐deposited BN are studied. The oxidation product is B 2 O 3 ( l ) and the oxidation kinetics are sensitive to crystallographic orientation, porosity, and impurity levels.…
A polymer (TPD-PPV), incorporating both efficient light-emitting and hole transporting moieties has been synthesized. This polymer also possesses excellent film-forming property, good thermal stability, and high electrochemical reversibility and stability. The HOMO-LUMO energy levels were determined by cyclic voltamme…
The frequency and temperature dependence of the optical conductivity of ferromagnetic manganites is explained within the framework of the bipolaron theory. As these materials are cooled below the Curie temperature, the colossal magnetoressitance (CMR) is accompanied by a massive transfer of the spectral weight of the…
The role that Al 3 Fe intermetallic inclusions play during initiation of pitting corrosion on aluminum alloys was investigated in 0.6 M NaCl. In aerated solutions microscopic observations showed the growth of cavities in the host metal adjacent to inclusions. The rest potential of synthetic Al 3 Fe was measured in aer…
A series of high-generation (G) ethylenediamine-core polyamidoamine (PAMAM) dendrimers corresponding to G = 5, 7, 9, and 10 were conjugated with the bifunctional chelate 2-(4-isothiocyanatobenzyl)- 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetate (p-SCN-Bz-DOTA). Gadolinium (III) ion was added to the macromolec…
Heparin is a potent anticoagulant which can be immobilized on biomaterial surfaces to increase their hemocompatability. In the present work, we have electrochemically synthesized composites comprising heparin and the electrically conducting polymer polypyrrole. The incorporation and exposure of heparin were controlled…
Low-energy metal-to-ligand charge-transfer (MLCT) excitations are associated with the very large molecular nonlinear optical (NLO) coefficients, β, of the complexes [RuII(NH3)5(N-R-4,4′-bipyridinium)]3+ (R=methyl, phenyl, or 4-acetylphenyl). Chemical oxidation to the RuIII forms causes bleaching of the MLCT absorption…
We show that polymeric materials characterized by two length scales are obtained if diblock copolymers are mixed with amphiphilic selective solvents, leading to self-organization which combines the “block copolymer length scale” with a much shorter “nanoscale”. In this work, the amphiphilic compound is 3- n -pentadecy…
Tracheary element differentiation requires strict coordination of secondary cell wall synthesis and programmed cell death (PCD) to produce a functional cell corpse. The execution of cell death involves an influx of Ca2+ into the cell and is manifested by rapid collapse of the large hydrolytic vacuole and cessation of…
Dc magnetization, ac susceptibility, and zero-field-cooled relaxation measurements are carried out for a cluster glass compound of ${\mathrm{La}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{CoO}}_{3}.$ The temperature dependence of the magnetic properties could be distinguished into two regimes: a high-temperature regime with th…
The Raman and infrared phonons of isostructural rhombohedral ${\mathrm{LaMnO}}_{3}$ and ${\mathrm{LaAlO}}_{3}$ are studied at room temperature. The experimental spectra are compared with the prediction of lattice-dynamical calculations and the lines observed are assigned to definite atomic vibrations. It is shown that…