Materials Literature
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Zirconia-based systems have been extensively studied for some 25 years, and a wealth of exciting results has been amassed. This book tracks the progress made in the field; from very early phase stability work, to modern approaches which involve quite sophisticated models for the transformation toughening that is assoc…
In the absence of suitable single crystals, the problem of determining the connectivity pattern of the title compound (and of its phenyl analogue), i.e. that of discriminating between two markedly different stereoisomers, has been solved by the powder diffraction technique. The structure was solved by ab initio XRPD m…
To improve adhesion between polypyrrole and glass, new pyrrole-substituted organotrialkoxysilanes coupling agents are synthesized and studied. Solubility, hydrolysis, and self-condensation features in aqueous solutions are investigated by IR, 1 H, and 29 Si NMR spectroscopies. Varying the experimental conditions of py…
We present first-principles total-energy calculations of (001) surfaces of SrTiO3. Both SrO-terminated and TiO2-terminated surfaces are considered, and the results are compared with previous calculations for BaTiO3 surfaces. The major differences are in the details of the relaxed surface structures. Our calculations a…
Monte Carlo simulations with an effective Hamiltonian parametrized from first principles are performed to study the dielectric response of BaTiO3 as a function of temperature, with particular emphasis on the behavior of the dielectric constant near the transition from the ferroelectric tetragonal phase to the paraelec…
The elastic theory of quasicrystals considers, in addition to the normal displacement field, three phason degrees of freedom. We present an approximative solution for the elastic Green's function of icosahedral quasicrystals, assuming that the coupling between the phonons and phasons is small.
First-principles calculations are performed to investigate alloying and ferroelectric effects in lead zirconate titanate (PZT) with high Ti composition. We find that the main effect of alloying in the paraelectric phase of PZT is the existence of two sets of B-O bonds, i.e., shorter Ti-O bonds vs. longer Zr-O bonds. O…
The electronic ground state of a periodic crystalline solid is usually described in terms of extended Bloch orbitals; localized Wannier functions can alternatively be used. These two representations are connected by families of unitary transformations, carrying a large degree of arbitrariness. We have developed a loca…
Starch ethers having side chains of various lengths, controlled and uniform degrees of substitution, and various amylose/amylopectin ratios were obtained by a one-step chemical modification of starch. Factors influencing the phase behavior of these starch ethers were carefully examined, and the ones having short side…
The improvements in mechanical properties obtained by orienting starch−ether films were further examined, specifically with regard to their dependence on degree of substitution of the starch and on its amylose/amylopectin ratio. It was found that the degree of substitution had little or no influence on the mechanical…
In the presence of dioxygen, four cobalt complexes of linear tetrapyrroles, Co(OEB) (OEB is the trianion of octaethylbiliverdin), [Co II (OEBOx)]I 3 (OEBOx is the monoanion of the oxidized form of octaethylbiliverdin), Co II (OEFB) (OEFB is the octaethylformylbiliverdin dianion), and Co II (OEBOMe) (OEBOMe is the dian…
Abstract Although the traditional fluid loss control systems used in high permeability completions have received considerable discussion in literature, most of the documentation reviews the application of individual systems only; little is provided on how to evaluate which method is best suited for a given situation.…
Methylpheophorbide- a (a chlorophyll a analog) was converted into methyl 13 1 -deoxypyropheophorbide- a 2 in excellent yield. The Ni(II) complex of 2 on hydrogenation and subsequent Vilsmeier reaction with phosphorus oxychloride and 3-( N, N -dimethylamino)acrolein produced Ni(II) methyl 20-(2-formylvinyl)-13 1 -deoxy…
Time-resolved (TR) small-angle X-ray (SAXS) experiments were conducted to monitor the development of microstructure and crystallinity in neat PEO and a representative composition from four, melt-miscible PEO blends. Although crystal thickening was not observed directly during the time scale of the experiments, compari…
Intermaterial dividing surfaces (IMDS) in strongly segregated block copolymer systems are typically of constant mean curvature (CMC). This observation largely derives from the interplay of the thermodynamics of chain deformation and interfacial tension. Recently, a compositionally symmetric, linear poly(2-vinylpyridin…
Small-angle neutron scattering has been applied for structural investigations of amine-terminated poly(propylene imine) dendrimer (Astramol) solutions in D 2 O as a function of concentration and acidity. The forward scattering, dΣ/dΩ( Q = 0), decreases progressively by increasing dendrimer concentration due to interde…
Significant effects on catalytic activity in the epoxidation of cyclohexene with alkyl hydroperoxides are observed when the surface of mesoporous silica (MCM-41) is modified with either Ge(IV) or Sn(IV) prior to the grafting of tetracoordinated Ti(IV). Titanium centers attached via oxygen to two silicons and one germa…
The three-dimensional structures of Corynebacterium glutamicum diaminopimelate dehydrogenase as a binary complex with the substrate meso-diaminopimelate (meso-DAP) and a ternary complex with NADP+ and an isoxazoline inhibitor [Abbot, S.D., Lane-Bell, P., Kanwar, P.S.S., and Vederas, J. C. (1994) J. Am. Chem. Soc. 116,…
The electrochemistry of nine different manganese(III) dodecaphenylporphyrins containing halogen or CF 3 groups on the phenyl rings of the porphyrin macrocycle is reported. Six of the compounds were previously synthesized while three of the derivatives, (DPPF 8 )MnCl, (DPPCl 12 )MnCl and (DPPF 28 )MnCl, are reported fo…
A new reactive copolymer system with high, but still variable glass-transition temperatures was synthesized. This was accomplished by copolymerizing various N-substituted maleimides with methylvinyl or vinyl isocyanate, so that a polymer with a 1:1 composition of the two monomers is obtained. Further functionalization…