Materials Literature
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Abstract This article deals with the preparation and characterization of silk fibroin ( Bombyx mori )/cellulose blend films. Following dissolution with a metal complex solution, the average molecular weight of silk fibroin slightly decreased. While cellulose was almost unaffected. After coagulation and washing, transp…
We present a real-space adaptive-coordinate method, which combines the advantages of the finite-difference approach with the accuracy and flexibility of the adaptive coordinate method. The discretized Kohn-Sham equations are written in generalized curvilinear coordinates and solved self-consistently by means of an ite…
In order to study the dynamics of the polymerization in liquid sulphur we have measured the transient absorption spectra after illuminating with a pulsed laser below and above the polymerization temperature, T p . We have found that photoinduced polymerization occurs below T p and there exist two kinds of relaxation p…
A combination of 25 Mg and 27 Al NMR has been shown to be an effective structural probe for the intermetallic phase Mg 17 Al 12 , able to detect precipitation of this phase in dilute alloys of aluminium in magnesium during age hardening, with well-resolved signals from the precipitate and the alloy. Knight shift and s…
The electronic structures for the metallic states of the organic solids ( ${R}_{1}$, ${R}_{2}\ensuremath{-}\mathrm{DCNQI}{)}_{2}M$ with $M\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\mathrm{Cu}$ and Ag are studied in the local density functional theory with the plane-wave pseudopotential method. The calculation…
Electron paramagnetic resonance (EPR) has been used to identify the primary electron and hole traps responsible for ‘‘gray tracks’’ in flux-grown KTiOPO4(KTP). Ionizing radiation (x rays) was used to produce the gray-track effect. During an irradiation at 0 °C, a broad absorption band peaking near 500 nm is introduced…
Although the frequency dependent conductivity of ion-containing glasses often displays scale invariant power law dispersion at high temperatures, the exponent increases to unity at lower temperatures. We report measurements of the conductivity of a series of alkali metaphosphate glasses including a mixed alkali compos…
Amorphous carbon (a-C) films grown by vacuum-arc deposition techniques contain substantial amounts of compressive, residual, growth stress (over 10 GPa). The magnitude of the stress can be controlled by changing the incoming energy of the ions. It is observed that stress shifts the Raman scattering feature in these fi…
We present a method for electronic structure calculations that retains all of the advantages of real space and addresses the inherent inefficiency of a regular grid, which has equal precision everywhere. The computations are carried out on a {\em regular} mesh in {\em curvilinear space}, which allows natural and effic…
The perovskite-type manganese oxide, ${\mathrm{Pr}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ $(x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.5)$, shows a first-order phase transition from a ferromagnetic (FM) metal to antiferromagnetic (AFM) nonmetal at 140 K, which accompanies the transition to…
The ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ system with $0.2\ensuremath{\lesssim}x\ensuremath{\lesssim}0.4$ has traditionally been modeled with a ``double-exchange'' Hamiltonian in which it is assumed that the only relevant physics is the tendency of carrier hopping to line up neighboring…
For the investigation of the contribution of dislocation slip on {123} glide planes during rolling deformation of b.c.c. transition metals a Taylor type model is used. The simulations are compared to experimental observations. Since the movement of dislocations on the activated glide systems gives rise to characterist…
An unusual dodecagallium cage is isolated from the oxidation and hydrolysis of [ t Bu 2 Ga(Spy)]. The structure of 1 consists of a [ t BuGa(μ‐X)Ga t Bu]‐capped oxocube (X = O, OH). In addition 2 has been isolated. Both structures show crystallographic disorder of oxo and hydroxo ligands. H‐Spy = 2‐mercaptopyridine. eq…
The effect of nitrogen and carbon on the electronic and magnetic properties of the iron-base Fe56Cr18Ni16Mn10 3d-alloy with f.c.c. lattice (austenite) is studied by means of the magnetic resonance. It is shown that the electron state density on the Fermi surface in the nitrogen austenite is one order of magnitude high…
Abstract The investigation of thermodynamic properties and reactivity yields interesting insights into the chemistry of newly synthesized substances. With thermal analysis extensive information can be gained from small samples (often only a few milligrams). In addition, the data obtained by thermal analysis can be use…
The optical rotation of poly(propylene imine) dendrimers with 64 identical enantiomerically pure amino acid end groups tends to zero. This remarkable behavior results from the packing of the end groups in the highly dense, multiply hydrogenbonded surface, which gives rise to different frozen‐in conformations, leading…
Below 4 K the [Au(CN)2] salt of the radical cation of 1 shows superconductivity. The X-ray structure analysis reveals that this salt has a two-dimensional array of donors. The relatively large interactions between the stacks result in a closed Fermi surface.
The thermal stability of the electric field induced poled order in a new class of second-order optically nonlinear polymers, "donor-imbedded" side-chain polyimides containing no flexible connectors or tethers to the nonlinear optical (NLO) chromophore, is investigated. In these polymers, the electron-donor part of the…
We present a method for reliably determining the lowest energy structure of an atomic cluster in an arbitrary model potential. The method is based on a genetic algorithm, which operates on a population of candidate structures to produce new candidates with lower energies. Our method dramatically outperforms simulated…
A class of amphiphilic macromolecules has been synthesized by combining well-defined polystyrene (PS) with poly(propylene imine) dendrimers. Five different generations, from PS-dendr-NH(2) up to PS-dendr-(NH(2))(32), were prepared in yields of 70 to 90 percent. Dynamic light scattering, conductivity measurements, and…