Materials Literature
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Absorption, excitation, emission spectra and lifetime measurements of cerium doped calcium metaphosphate glass in the concentration range 3.83x10 18 -6.34x10 20 ions cm -3 are investigated. The ultraviolet absorption spectra reflects the 4f→5d transitions where the 5d state is split into five levels due to the cubic c…
Consolidation and fracture dynamics in nanophase amorphous Si3N4 are investigated using 106‐atom molecular‐dynamics simulations. At a pressure of 15 GPa and 2000 K, the nanophase system is almost fully consolidated within a fraction of a nanosecond. The consolidation process is well‐described by the classical theory o…
The structure of silicon boride, ${\mathrm{SiB}}_{3},$ is based on 12-atom, boron-rich icosahedra in which silicon atoms substitute for some boron atoms. Raman bands associated with vibrations of icosahedral atoms in ${\mathrm{SiB}}_{3}$ are quite broad, reflecting this substitutional disorder. Comparing the Raman spe…
Coccolithophorids are marine unicellular algae characterized by their ability to carry out controlled, subcellular calcification. The biochemical and kinetic features of membrane‐bound Ca 2+ ‐stimulated ATPases have been examined. Membranes and organelles from axenic cultures of Pleurochrysis sp. (CCMP299) were isolat…
Human parathyroid hormone (hPTH) is involved in the regulation of the calcium level in blood. This hormone function is located in the NH2-terminal 34 amino acids of the 84-amino acid peptide hormone and is transduced via the adenylate cyclase and the phosphatidylinositol signaling pathways. It is well known that trunc…
Several plano-convex aluminum thin films, ~30 nm thick in the center and ~2 mm in diameter, were deposited on microscope cover slides to function as inverse-Gaussian transmittive filters. By placing one of these filters in front of the Gaussian He-Ne laser, we can modify the beam intensity profile in the downstream di…
Ferroelectric phase transition developing in a random field of static defects is studied by the computer simulation method. The chosen free energy provides the stability of the ferroelectric phase in the absence of defects. The simulation model takes into account the transformation-induced strain and the dipole—dipole…
A reaction‐plane model is used to examine the behavior of copper in aerated acid sulfate solution at or near the open‐circuit potential. The model predicts that when dissolved oxygen is present, the metal will corrode at a mixed potential determined by the and couples. The mixed potential in an aerated solution is neg…
The nematic orientation close to a solid substrate is investigated by means of a Landau--de Gennes phenomenological model. We show that a spatial variation of the scalar order parameter induces a subsurface variation of the average molecular orientation and an intrinsic contribution to the anchoring when the splay and…
Abstract Mono-15-crown-5-substituted bis(phthalocyaninato)lutetium was synthesized. By addition of potassium cation in solution, the phthalocyanine dimer radical formed a supramolecular structure which preserves two unpaired electrons and shows a ESR signal of a triplet state. From observed zero field splitting consta…
The external field induced paranematic–nematic phase separation of hard spherocylinder systems is studied using the Onsager and Parsons free-energy functionals. A bifurcation analysis is carried out in the context of the Onsager theory at an infinitesimal external field. The bifurcation concentration is found to decre…
Raman scattering was used to study two model relaxor ferroelectrics, namely PbMg1/3 Nb2/3O3(PMN) with the 1:2 stoichiometric composition of Mg2+ and Nb5+ ions in the oxygen octahedrons and PbSc1/2Ta1/2O3 (PST) with the 1:1 stoichiometric composition of Sc3+ and Ta5- ions. In spite of a different stoichiometric ratio t…
The properties of supercooled liquids are particularly interesting because they cannot be understood simply as an extension of liquid properties at temperatures above the melting point, and in this sense they are anomalous. These anomalies include apparent divergences and thermodynamic contradictions. We give a genera…
We report a comprehensive investigation of nanophase palladium by x-ray-absorption spectroscopy with the aim of clarifying the issue of the structure of the grain boundaries in nanophase materials. In fact, since the proposal that the grain boundaries in these materials are highly disordered, various techniques have o…
C. glutamicum meso-diaminopimelate dehydrogenase is an enzyme of the L-lysine biosynthetic pathway in bacteria. The binding of NADPH and diaminopimelate to the recombinant, overexpressed enzyme has been analyzed using hydrogen/deuterium exchange and electrospray ionization/mass spectrometry. NADPH binding reduces the…
Poly-beta-hydroxybutyrate was determined in lactic acid bacteria belonging to the genera Lactobacillus, Lactococcus, Pediococcus and Streptococcus. Lactobacilli were grown in MRS broth, the others were grown in Elliker broth medium. Cell biomass was obtained by centrifugation. The cell walls were lysed with sodium hyp…
Traditional electrochemical tests and the contact electrical resistance technique (CER) were used to investigate the effect on corrosion of pure copper (99.999 wt%) of adding benzotriazole (BTA) and 1-hydroxybenzotriazole (1-OH-BTA) to acidic solutions (sulfuric acid [H2SO4], pH = 1.7, and sodium sulfate [Na2SO4] unti…
Carbon nanotubes synthesized by decomposition of acetylene over silica-supported cobalt catalysts were fluorinated in different conditions : at room or high temperature, ca. 500°C. The electrochemical behaviour of these carbon nanotube fluorides as electrode materials in a lithium cell was investigated using a liquid…
Influence of oxygen on the thermal stability of amorphous hydrogenated carbon (a-C:H) films is investigated by annealing the films at 520, 610, and 670 K in vacuum and in O2 flow, respectively. The a-C:H films used for this study were deposited using microwave plasma from a mixture of 10 sccm pure methane and 100 sccm…
Orientation Imaging Microscopy (OIM) in the scanning electron microscope (SEM) has proven itself to be a powerful tool for investigating local orientation relationships in polycrystalline microstructures. Because of the inherent limitations of electron backscatter diffraction in the SEM, the OIM technique is limited t…