Materials Literature
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We present a simple and direct proof that the exchange-correlation hole, and therefore the exchange-correlation energy, in a polarized insulator is not determined by the bulk density alone. It is uniquely characterized by the density and the macroscopic electric polarization of the dielectric medium.
A matching algorithm for the identification of backbones in percolation problems is introduced. Using this procedure, percolation backbones are studied in two- to five-dimensional systems containing 1.7x10^7 sites, two orders of magnitude larger than was previously possible using burning algorithms.
Using a combination of first-principles total energies, a cluster expansion technique, and Monte Carlo simulations, we have studied the Li/Co ordering in LiCoO_2 and Li-vacancy/Co ordering in CoO_2. We find: (i) A ground state search of the space of substitutional cation configurations yields the (layered) CuPt struct…
We report the observation of single nanotube fragmentation, under tensile stresses, using nanotube-containing thin polymeric films. Similar fragmentation tests with single fibers instead of nanotubes are routinely performed to study the fiber-matrix stress transfer ability in fiber composite materials, and thus the ef…
The explanation is presented for the temperature dependence of the fourfold intensity peak splitting found recently in diffuse scattering from the disordered Cu3Au alloy. The wavevector and temperature dependence of the self-energy is identified as the origin of the observed behaviour. Two approaches for the calculati…
The relationship between the type of activator and the morphology of polycaproamide (PCA) powders was investigated. The powders were prepared by anionic polymerization of caprolactam in ethylbenzene using sodium caprolactamate as initiator and CO2, diisopropylcarbodiimide, and dicyclohexylcarbodiimide as activators. T…
Meltblown is one of the fastest growing processes for nonwoven production. The design of the coat-hanger geometry of a die is very important for meltblown technology. In this article, melt rheological properties were studied based on capillary rheometry, followed by analysis and simulation of the melt flow in the die…
Effects of catalyst acidity and the restricted reaction volume afforded by HZSM-5 on the catalytic cracking of polypropylene are described. Polypropylene cracking by silica—alumina and HZSM-5 catalysts yields olefins as primary volatile products. In addition, HZSM-5 channels restrict carbenium ion rearrangements and f…
(1,2-Naphthalocyaninato)lutetium(III), bis(1,2-naphthalocyaninato)lutetium(III), and tris(1,2-naphthalocyaninato)dilutetium(III) have been synthesized in good yields. These complexes were characterized by UV-visible, (1)H NMR, and mass spectroscopies and by electrochemical techniques. Bis(1,2-naphthalocyaninato)luteti…
The structures and electrical properties of four NASICON compositions, Na 1.4 M 1.6 In 0.4 (PO 4 ) 3 (M = Ti, Sn, Hf, Zr), have been determined and compared. Rietveld refinement of powder X-ray diffraction data confirmed the basic rhombohedral NASICON structure with random occupancy of the octahedral In/M sites, full…
The success of the "Cluster Variation Method" (CVM) in reproducing quite accurately the free energies of Monte Carlo (MC) calculations on Ising models is explained in terms of identifying a cancellation of errors: We show that the CVM produces correlation functions that are too close to zero, which leads to an overest…
As part of a series of studies on energy transfer processes between optical centers in condensed matter, an analysis is made of the problem of a crystalline system made up by a majority of regular optical centers and small amounts of defective optical centers. Within the conceptual framework of the crystal model, anal…
Depopulation of the S2 excited electronic state of the Zn-tetraphenylporphyrin (ZnTPP) was monitored by measuring the decay of S2→S0 and the rise of S1→S0 fluorescence using the up-conversion fluorescence technique with a time-resolution of 120 fs. The lifetime of the S2 electronic state, measured for ZnTPP in ethanol…
Monodisperse melts of ABC linear triblock copolymer are examined using self-consistent field theory (SCFT). Our study is restricted to symmetric triblocks, where the A and C blocks are equal in size and the A/B and B/C interactions are identical. Furthermore, we focus on the regime where B forms the majority domain. T…
Tight-binding electronic band structures of cesium trihalometalates CsGeX(3) (X = Cl, Br) were calculated to examine the pressure-dependence of their crystal structures and band gaps as well as their primitive cubic to rhombohedral structural phase transitions. In agreement with experiment, our calculations show that…
We introduce a model for fractures in quenched disordered media. This model has a deterministic extremal dynamics, driven by the energy function of a network of springs (Born Hamiltonian). The breakdown is the result of the cooperation between the external field and the quenched disorder. This model can be considered…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHeterogeneous CatalysisNoritaka Mizuno and Makoto MisonoView Author Information Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan Cite this: Chem. Rev. 1998, 98, 1, 199–218Publication Date (Web):Janua…
In recent years much attention has been paid to the study of radiation-induced defects in laser and luminescent materials, since they affect the optical and stimulated emission properties. Defects in : powder prepared by solid state diffusion have been studied by thermoluminescence (TL) and fluorescence measurements.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMultifunctional and Chiral Porphyrins: Model Receptors for Chiral RecognitionHisanobu Ogoshi and Tadashi MizutaniView Author Information Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-01, Japa…
The paper reviews solid-catalyzed oxidation and reduction processes for the treatment of wastewater that contains small concentrations of toxic compounds and for which separation is not economical while biological treatment is not feasible. Specifically, the objectives are (1) to understand the interactions between ca…