Materials Literature
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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…
The connections between microscopic dynamical processes and macroscopic viscous transport are not well known in multi-component oxide liquids, despite their importance in the glass industry and in the earth sciences. Here, rates of exchange among both silicate and borate network species in an alkali borosilicate liqui…
Effects of corrosion of alloys are evaluated in nickel‐metal‐hydride (Ni‐MH) cells. Particularly, it is shown how Al released by the corroded alloys pollutes the positive electrode, which endures a loss of charging efficiency, due to the formation of an hydrotalcite‐like phase stabilized with Al. Furthermore, since Al…
Polymorphic phase transitions between alumina structures based on fcc packing of oxygen have been studied by electron diffraction and highresolution electron microscopy. A new metastable alumina polymorph with monoclinic symmetry was identified in alumina obtained by both plasma spraying and thermal oxidation of alumi…
Demand for improved battery systems for electric vehicles and power sources in general suggests the need for more accurate descriptions of the solid‐state and electrochemical reactions which may affect active‐material usage. Tetrabasic lead sulfate ( 4 PbO ⋅ PbSO 4 ) is an intermediate phase commonly formed during pro…
A theory of radiative resonant x-ray Raman scattering by polymers and solids is presented. A detailed analysis demonstrates the crucial role of the momentum exchange between valence electrons and photons and between valence electrons and the core hole. It is shown that resonant inelastic x-ray scattering (RIXS) cross…
Lipase-catalyzed ring-opening polymerization of α-methyl-substituted medium-size lactones, α-methyl-δ-valerolactone and α-methyl-ε-caprolactone, were carried in bulk. Immobilized lipase derived from Candida antarctica is active in the polymerization of both monomers. The polymerization proceeds under mild reaction con…
A criterion has been formulated for transcrystalline and intercrystalline fracture caused by the evolution of voids located both in a grain and on grain boundaries. The criterion is based on the idea of plastic collapse for a unit cell that is a regular structural mezovolume of polycrystalline material. The criterion…
AB and ABA block copolymers are synthesized by direct living anionic polymerization where the A-block is a liquid crystalline side chain polymer (LC-block) and the B-block is an isotropic polymer (I-block). Similar to amphiphilic block copolymers with a “hydrophilic” water soluble segment and a “hydrophobic” water ins…
The cholesteric pitch P of semiflexible helical polymer solutions was formulated using a threaded equivalent freely jointed chain model. The theory was favorably compared with experimental results of P for cholesteric solutions of the three helical polymers schizophyllan (a triple-helical polysaccharide), poly(γ-benzy…
Diamond microelectrodes are fabricated using microwave plasma CVD for the growth of electrically conducting single microcrystallite diamonds as well as diamond films on etched tungsten wires which are subsequently sealed in glass. The electroactive diamond is exposed by either mechanical polishing or by chemical etchi…