Materials Literature
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We show how methods based on an encounter model for diffusion can be used to simulate the grain-boundary diffusion coefficients in ceramics. Boundaries in NiO and ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ are used as examples of the method. The anisotropy of diffusion in boundaries (expected from the picture of a grain boun…
Ferroelectric ordering in a nematic liquid crystal system is described using a generalized mean-field potential including effective potentials for both axial and polar interactions. From a self-consistent numerical analysis, a complete phase diagram is obtained as a function of the axial and polar interaction potentia…
The thermodynamic forces between hydroxypropylcellulose (HPC) molecules at close separation have been measured using the osmotic stress method coupled with X-ray scattering. Two force regimes are apparent: a very short ranged, temperature insensitive force that dominates interactions within the last 2.5 Å separation a…
A series of cyclopalladated carbosilane dendrimers functionalized with monoanionic [C 6 H 4 (CH 2 NMe 2 )-4] - (= CN) C,N-chelating ligands via a multiple and selective C−H bond activation process have been prepared. The structure of the support, i . e ., the branching degree as well as the nature of the alkanediyl li…
Equation (9) is corrected to Figure 19(b) is also corrected. Figure 1. Geometry. The angles θ, ϕ, and ξ are defined, specifying the transformed magnetizations. The angles are functions of position, y .
Fresnoite ${\mathrm{Ba}}_{2}{\mathrm{Si}}_{2}{\mathrm{TiO}}_{8}$ is a ferroelectric with promising piezoelectric uses that exhibits unusual pyroelectric, elastic, and other property anomalies close to 433 K. X-ray diffraction analyses at 297 and 573 K by Markgraf et al. determined the space group to be $P4\mathrm{bm}$…
Poly-(R)-3-hydroxybutyrate/polyphosphate (PHB/polyP) complexes, whether isolated from the plasma membranes of bacteria or prepared from the synthetic polymers, form ion channels in planar lipid bilayers that are highly selective for Ca(2+) over Na(+) at physiological pH. This preference for divalent over monovalent ca…
Single-crystalline Bi nanowire arrays have been assembled into the nanochannels of anodic alumina membranes by electrodeposition. X-ray diffraction and transmission electron microscopy investigations revealed that the nanowires with diameter of either 50 nm or 20 nm are essentially single crystalline and highly orient…
Magnetic and structural properties of RCo12-xTix with R = Y and Sm and YFe12-xTix compounds have been investigated by using x-ray diffraction and magnetic measurements. It was found that all compounds investigated are almost single phase with the ThMn12-type structure. X-ray diffraction patterns of magnetically aligne…
We present QSPR models for normal boiling points employing a neural network approach and descriptors calculated using semiempirical MO theory (AM1 and PM3). These models are based on a data set of 6000 compounds with widely varying functionality and should therefore be applicable to a diverse range of systems. We incl…
Different types of ordered solid films of oxotitanium(IV) phthalocyanine (OTiPc) were grown in 50−500 nm thickness by vacuum deposition onto such conventional substrates as metal- and ITO-coated glass and neat glass at a rate of ∼0.05 nm s - 1 . Under 10 - 3 −10 - 4 Pa isotropic films with short-range molecular organi…
We investigated the problem of adsorption of a single semiflexible polymer chain on to a planar, homogeneous surface using off-lattice Monte Carlo simulations. Adsorption characteristics were studied at different temperatures for chains of various stiffnesses. We have found that the stiffer chains adsorb more onto the…
Ab initio molecular orbital and density functional calculations on isodesmic disproportionation reactions of nitrated cubanes indicate that the repulsion between nitro groups on adjacent carbons in octanitrocubane (ONC) is surprisingly small and that the energy required for successive substitutions of nitro groups on…
An intimate relation between structure and mechanical properties of regenerated cellulose (Rayon, Benberg, etc.) has been investigated by measuring the humidity and temperature dependencies of infrared spectra, X-ray diffraction, and dynamic viscoelastic properties. At first the dynamic viscoelastic property and the i…
How fast a droplet will spread on a solid surface depends on the surface tension gradient and the wettability. The temperature dependence of the surface tension is exploited in a so-called Marangoni flow, but capillary forces can counteract this type of flow. Wasan et al. highlight the report by Danielet al., who have…
Typically single-particle SEM/EDX analysis of aerosols is done on polycarbonate filters or solid carbon substrates. This has led to a widespread conclusion that EDX provides poor information on carbon, oxygen, and nitrogen content of a particle and usually could not go below 0.5-microm particles. We show that use of g…
The acid and surface properties of WO x −ZrO 2 solid acid catalysts were examined as a function of WO x surface density. Surface density strongly influences the size and electronic properties of WO x domains and the rate of acid-catalyzed reactions on these materials. The adsorption and isotopic exchange of acid and r…
A cluster Monte Carlo method for systems of classical spins with purely dipolar couplings is presented. It is tested and applied for finite arrays of perpendicular Ising dipoles on the triangular lattice. This model is a modification with long-range interactions of the geometrically frustrated Ising antiferromagnet. F…
The relativistic generalization of the theory of superconductivity is reviewed with respect to its conceptual basis and first applications. The construction of relativistically covariant order parameters for superconductors is outlined and the generalization of the Dirac equation for the superconducting state is prese…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTMesoporous Polystyrene MonolithsAndrew S. Zalusky, Roberto Olayo-Valles, Charles J. Taylor, and Marc A. HillmyerView Author Information Department of Chemistry, University of Minnesota Minneapolis, Minnesota 55455 Cite this: J. Am. Chem. Soc. 2001, 123, 7, 1519–1520Pub…