Materials Literature
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A new order-N method for calculating the electronic structure of general (non-tight-binding) potentials is presented. The method uses a combination of the ``purification''-based approaches used by Li, Nunes and Vanderbilt, and Daw, and a representation of the density matrix based on ``travelling basis orbitals''. The…
We show that there are qualitative differences between the temperature dependence of the spin and charge correlations in the normal state of the 2D attractive Hubbard model using quantum Monte Carlo simulations. The one-particle density of states shows a pseudogap above $\tc$ with a depleted $N(0)$ with decreasing $T$…
{}From a series of total energy calculations by the full-potential linear muffin-tin orbital method, the total energy hypersurface as function of atomic displacements from equilibrium positions has been fitted for different Gamma phonon modes in orthorhombic KNbO3. Frequencies and eigenvectors of all TO Gamma phonons…
A glass network of N atoms with n(1) of the atoms with a coordination number of 1, and m(2) of the atoms with a coordination number of 2 about which the bond-angle constraint is broken, will in general display a stiffness threshold (rigidity percolation threshold) when the average coordination increases to a critical…
Mechanical support in animals is performed by connective tissues. The soft tissues consist of collagen fibres embedded in a highly hydrated proteoglycan gel. By considering them as fibrous composite materials, a unifying theme can be found to explain their mechanical behaviour in terms of their structure and compositi…
We performed high-dimensional quantum dynamical calculations of the dissociative adsorption and associative desorption of hydrogen on Cu(111). The potential energy surface (PES) is obtained from density functional theory calculations. Two regimes of dynamics are found, at low energies sticking is determined by the min…
The elastic strain state in a 25 nm (In,Ga)As epitaxic film deposited on a (001) GaAs substrate includes a Poisson expansion perpendicular to the interface. This creates a tetragonally distorted lattice in the film which shifts high-order Laue-zone (HOLZ) lines in electron channeling patterns (ECP) from the film compa…
An orientation-dependent etching behavior has been observed during diffusional thinning of single crystal diamond by molten cerium. The etching rate at 920 °C was in the order of {111}≳{100}≳{110} with a relative ratio of about 5:2:1. This diamond etching anisotropy is tentatively attributed to the orientation-depende…
A new class of exact solutions is reported for an evolving bubble in a two-dimensional slow viscous flow. It is observed that for an expanding bubble the interface grows smoother with time, whereas the contracting-bubble solutions display a tendency to form sharp corners ("near cusps") for small values of surface tens…
Abstract In order to improve upon certain properties of gelatin graft copolymerization of acrylonitrile (AN) and methacrylonitrile (MAN) onto gelatin has been studied in aqueous medium using γ rays as a source of initiation. Optimum conditions for affording maximum percentage of grafting have been evaluated as a funct…
Abstract Binary blends of poly(caprolactone) (PCL) with cellulosic esters [cellulose diacetate (CDA), cellulose acetate–butyrate (CAB), and cellulose triacetate (CTA)] were studied by using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and wide‐angle X‐ray scattering (WAXS) techniques, an…
The PbO loss during rapid thermal annealing of PbTiO3 thin films prepared by the sol-gel method has been investigated using electron probe microanalysis. The results have been correlated with the x-ray diffraction analyses and the dielectric properties of the films. The films start to loose PbO significantly during an…
Porphyrinisomere im Aufwind. Bis zur Entdeckung des Porphycens waren Porphyrinisomere völlig unbeachtete Tetrapyrrol‐Makrocyclen. Jetzt konnte ein als Corrphycen bezeichnetes neues Isomer als Tetraethyltetramethylderivat 1 in einer reduktiven Carbonylkupplung synthetisiert werden. 1 weist ein planares Ringgerüst auf u…
Abstract Thermal and flow properties of perlite‐filled high‐density polyethylenes (HDPE), studied in the first part of the paper, are discussed. Maximum peak temperatures of endotherms ( T mp ) and the corresponding relative peak heights were examined by differential scanning calorimetry (DSC). The data obtained from…
The thermoluminescence of ultraviolet- (250 nm) and X-ray-irradiated KCl:Eu 2+ is investigated. The peaks are located in the same positions independent of the radiation used to excite the sample, with differences only in the peak intensity ratios. Thermal and optical bleaching methods allow us to relate the thermolumi…
Abstract The effect of polymer structure on blend miscibility with polyvinylphenol (PVPh) has been studied for at least one polymer from a variety of polymer classes with potential hydrogen‐bond accepting groups: polyesters (aliphatic and aromatic), polycarbonates, polyimides, polyamides, polysulfones, polyurethanes,…
We reexamine the density functional theory of laser-induced freezing, i.e., the freezing of a colloidal liquid into crystalline order in the presence of an external periodic modulating potential ${V}_{e}$ with its wave vectors tuned to the ordering wave vector in the liquid phase. We show definitively that the initial…
Variation of the preparation conditions of porous silicon carbide is shown to have a strong effect on the structural and electrical properties of the material obtained. A correlation has been observed between the fiber size and resistivity of porous SiC, a decrease of fiber size results in a semi-insulating material d…
Abstract Four different types of high‐density polyethylenes (HDPE) were blended with perlite at different concentrations. Silane coupling agent γ‐aminopropyltriethoxv silane (γ‐APS, A‐1100) was used to enhance the adhesion between perlite and HDPEs. Ultimate tensile strength and elastic modulus increased as the perlit…
The very high pressures (>1 GPa) that occur during the final stages of collapse of a cavitation bubble force the liquid near the bubble wall briefly (\ensuremath{\sim}1 ns) into a metastable state of subcooling, relative to the equilibrium phase diagram. Estimates for water show that solidification in the form of h…