Materials Literature
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Crystal-engineering strategies have been systematically developed for the rational design by self-assembly of diverse metalloporphyrin molecular-sieve materials. Cooperative coordination and hydrogen bonding algorithms of molecular recognition proved particularly useful for this aim. The supramolecular concepts used i…
A new formalism to calculate the transmission coefficient t of electrons from a material L into the same material L through a barrier B is presented. The barrier B is arbitrary and can be metallic, semiconducting or insulating. The important feature of this formalism is that it starts from the electronic structure of…
We introduce an electrostatic model including charge transfer, which is shown to account for the observed B-site ordering in Pb-based perovskite alloys. The model allows charge transfer between A-sites and is a generalization of Bellaiche and Vanderbilt's purely electrostatic model. The large covalency of Pb^{2+} comp…
Based on spin-density functional theory we calculate the electronic structure of a tunnel junction consisting of two magnetic Fe layers separated by an insulating vacuum barrier selfconsistently. For the conductance the Landauer formula is evaluated in the ballistic limit as function of the magnetic configuration. Bas…
We formulate and prove a variational principle (in the sense of thermodynamics) for random domino tilings, or equivalently for the dimer model on a square grid. This principle states that a typical tiling of an arbitrary finite region can be described by a function that maximizes an entropy integral. We associate an e…
Determination of the tendencies of amino acids to form alpha-helical and beta-sheet structures has been important in clarifying stabilizing interactions, protein design, and the protein folding problem. In this study, we have determined for the first time a complete scale of amino acid propensities for another importa…
Titania- and zirconia-supported gold particles of 1−5 nm size, prepared by various routes of synthesis, were employed in the partial hydrogenation of acrolein. In-depth characterization of their structural and electronic properties by electron microscopy, electron paramagnetic resonance, and optical absorption spectro…
At least in principle, a very large number of rubber-plastic blends are possible (Corish and Powell, 1974; Dunn, 1976). However, in this chapter we will be concerned with those compositions, which are soft or flexible and which have rubber-like elasticity, in that they retract forcibly from large deformations. Such co…
Optical properties of thin films and bulk materials at short wavelengths, including 157 nm and shorter, are needed for development of new lithographic processes, new fundamental science, and new metrology in the semiconductor, optical and data storage industries. Variable angle spectroscopic ellipsometry offers non-de…
Performance of Ni/C, Ni/B<SUB>4</SUB>C, Mo/B<SUB>4</SUB>C and W/B<SUB>4</SUB>C multilayers in the energy range E > 8 keV is considered by simulation of x-ray reflectivity and resolution of 1st order Bragg reflection at three different photon energies. The results indicate, that Ni/C and Ni/B<SUB>4</SUB>C multilayer…
A novel trimeric porphyrin array in which the macrocycles are directly fused through their β-pyrrolic carbons has been prepared and investigated. These molecules feature a 7,8,17,18-tetraethylporphyrin moiety flanked on opposite sides by two tetraphenylporphyrin (TPP) moieties. The 2,3 and 12,13 β-carbon positions of…
EPDM is the designation agreed upon by ASTM and IISRP for ethylene-propylene rubber, \nwhere "E" and "P" stand for ethylene and propylene, respectively. "D" designates the nonconjugated diene that provides a site of unsaturation for sulfur vulcanization, and "M" refers to \nthe polymethylene saturated backbone of the…
Guayule rubber Hevea natural rubber modified natural rubber chemical modification of synthetic elastomers liquid rubber powdered rubber rubber-rubber blends - part 1 rubber-rubber blends - part 2, new developments short fibre-filled rubber composites thermoplastic styrenic block copolymers polyester thermoplastic elas…
Microporosity and connectivity of ordered mesopores of SBA-15 silica were studied using nitrogen adsorption and novel methods based on selective pore blocking via organosilane modification, and on the imaging of inverse platinum replica of ordered mesoporous structure. It was found that SBA-15 exhibits a relation betw…
For years, HCs with zero ODP and low GWP have been used as alternative B.A. (blowing agents) in the appliance industries. The improvement of insulation performance and lowering costs are significant factors in the development of R-PU (rigid polyurethane) foams especially blown with HCs. The development of R-PU foam wi…
Based on material parameters of diamond and typical experimental data of inverse temperature dependence of electrical conductivity, the temperature coefficient of the resistance of a semiconducting diamond, has been calculated and combined with classic NTC, and platinum thermistors. The results indicate that a boron-d…
Proton nuclear magnetic resonance absorption spectra and spin-lattice relaxation rates in yttrium dihydride have been measured in the temperature range from 4.2 to 310K at 36.0MHz. The second moment of the resonance line corresponds to the rigid-lattice regime for YH1.99 and its value agrees with the anticipated CaF2…
The spectral and luminescent properties of solutions of perylenetetracarboxylic acid (PTCA), its ionic forms, and its aggregates and complexes with rare-earth ions are studied. The mechanisms of the fluorescence quenching of PTCA upon complex formation are discussed. It is concluded that the complex formation in such…
Methods of local porous layer formation by stain etching in HF : HNO3 : H2O solution have been proposed to form a dielectric isolation of devices. The production cycle includes direct ion implantation into local areas by focused ion beam or standard ion implantation through a resist mask followed by stain etching and…
The surface of polycrystalline diamond films during reactive ion etching in electron cyclotron resonance SF6 and O2 plasmas has been examined by scanning electron microscopy, Raman spectroscopy, and x-ray photoelectron spectroscopy. A SF6 plasma required a high voltage in negative substrate biasing in order to achieve…