Materials Literature
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The surface segregation of diblock copolymers and polymer blend thin films has been studied using a molecular theory. It was found that chains composed of short flexible segments always segregate to the surfaces. For flexible-stiff diblocks the flexible block segregates to the surface in most cases, while in polymer b…
The structures of B3N2, B2N3, and BN4 have been investigated using complete active space SCF (CASSCF) and augmented coupled cluster (CCSD(T)) methods. B3N2 has a symmetry-broken linear ground state structure BNBNB(2Σ+) and is very stable. B2N3 has a linear ground state structure BNBNN(2Π) and is nearly isoenergetic wi…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
PVOF has a very simple chemical formula, -CH:z-CF:z-, intermediate between polyethylene (PE) -CH:z-CH:z-and polytetrafiuoroethylene (PI&s;FE) -CF:z-CF:z-. This simplicity of chemical structure gives both high flexibility (as much as PE) and some sterochemical constraint (as seen in PTFE) to the main-chain structure of…
The intensity of surface Raman scattering from molecules adsorbed to a silver island film placed on top of a silver mirror, with an interlying quartz spacer layer of variable height, is found to vary considerably with spacer thickness. For quartz thicknesses up to 150 nm, the modulation of the Raman intensity is disti…
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…