Materials Literature
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Fluid metals are typical examples of materials whose electronic structures depend strongly on the thermodynamic state of the system. The most striking manifestation of this state dependence is the metal–non–metal transition which occurs when the dense liquid evaporates to the dilute vapour or when the fluid is expande…
The use of polymer-dispersed liquid crystal films to fabricate gratings was demonstrated. The written gratings are permanent, but are electrically switchable. In this article, we report the results obtained from the dynamical studies of gratings formed in polymer-dispersed liquid crystal films having various liquid cr…
The affect of annealing polycrystalline chemical vapor deposition (CVD) diamond in vacuo up to 1900 K has been studied using electron paramagnetic resonance (EPR) and infrared absorption. The concentration of the EPR centers at $g=2.0028$ and the infrared absorption in the CH region are insensitive to annealing below…
The effects of isotopic substitution on the $\ensuremath{\Gamma}$-point phonon in isotopically enriched ${(}^{70}\mathrm{Ge}$, ${}^{73}\mathrm{Ge}$, ${}^{74}\mathrm{Ge}$, and ${}^{76}\mathrm{Ge}$) and disordered (natural Ge and ${}^{70/76}\mathrm{Ge}$) germanium samples have been measured with Raman spectroscopy. We b…
The first-order Raman frequency shifts of the A g (2) + B g (2) mode in a CaWO 4 crystal were measured in the temperature range of 77∼771 K. The frequency shift for this mode changes very slowly with increasing temperature. The temperature dependence of the frequency shift of the A g (2) + B g (2) mode was analyzed us…
The title compound, lanthanum aluminium borate, has been found to be isostructural with hexagonal NdAl2.07(B4O10)O0.6. Each La ion is coordinated by six O-atoms to form a trigonal prism, while each Al is coordinated by five O-atoms to form a pyramid.
Polymer solutions do not wet the substrate, even when the solvent is wetting. It is suggested here that it becomes difficult to squeeze polymer molecules into thin films found near the contact line due to adverse changes in the polymer entropy. Models are used to show that as the film thins a potential barrier is enco…
One-pot oxidation polymerization of dithiols, obtained from bifunctional five-membered cyclic dithiocarbonates (4a and 4b) with two equivalents of amines, was studied. The monomers 4a and 4b were synthesized by the reactions of bisphenol A diglycidyl ether and neopentyl glycol diglycidyl ether with carbon disulfide, r…
The electronic structures have been calculated using the INDO/S-CI method, and following combination with the sum-over-sates method the dynamic second-order polarizabilities have been computed for the ${\mathrm{Ba}}_{3}{(\mathrm{B}}_{3}{\mathrm{O}}_{6}{)}_{2}$ microspecies of $\ensuremath{\beta}\ensuremath{-}{\mathrm{…
The nanocrystalline hard magnetic Nd2Fe14B phase plays a crucial role in the development of exchange spring magnets. We report the hardening mechanism of nanocrystalline Nd2Fe14B, as well as the effect of small amounts of magnetic additions on the hardening behavior. It is shown that the hardening mechanism is of the…
By allowing interactions between electrons, a Harper's equation is derived to examine the effects of electron correlations on the Hofstadter energy spectra. It is shown that the structure of the Hofstadter butterfly for the system of correlated electrons is modified only in the band gaps and bandwidths, but not in the…
We apply ab initio quantum-chemical methods to calculate correlation effects on cohesive properties of GdN, thereby extending the recently proposed incremental method to rare-earth compounds. Our calculated values are in reasonable agreement with the experimental cohesive energy (86.0%) and the experimental lattice co…
The oxidation of an Al(111) single-crystal surface induced by 100 eV electron bombardment in water vapor at room temperature has been studied using x-ray photoemission spectroscopy and electron-energy-loss spectroscopy. Electron bombardment significantly increases the growth rate and changes the observed growth-rate l…
In a measurement of pulsed laser deposition of ${\mathrm{SrTiO}}_{3}$ on ${\mathrm{SrTiO}}_{3}(001),$ we demonstrate that the difference in relative reflectivity change $\ensuremath{\Delta}R/R$ between $s$- and $p$-polarized light can be used in a real-time monitor of thin film growth at the level of a single atomic l…
We present a procedure that locally determines the composition (from a given set of available materials) of a segmented or graded thermoelectric generator leg in order to maximize its output power to a matched load. The method is based on a new interpretation of the electrical output relation, which is organized to re…
Using deuteron NMR techniques two-, effective three-, and various four-time correlation functions were recorded for supercooled ortho-terphenyl at 10–15 K above the calorimetric glass transition in order to characterize the heterogeneous nature of its primary response. The experimental results could successfully be de…
The block copolymers of poly(butylene succinate) (PBS) and poly(butylene terephthalate) (PBT) were synthesized by melt processing for different times. The sequence distribution, thermal properties, and crystallization behavior were investigated over a wide range of compositions. For PBS/PBT block copolymers it was con…
Several junctions between different nanotubes have been constructed which preserve the C ${\mathrm{sp}}^{2}$ honeycomb lattice with the sole insertion of a pentagon and a heptagon. This construction bends the structure at an angle that depends on the distance between the pentagon and heptagon. The atomic structure of…
We present a theoretical result on the ordering of cylindrical morphology in diblock and triblock copolymers. The equilibrium morphology of A–B diblock and A–B–A triblock copolymer films is shown to have the cylinders oriented parallel or vertical to the surface, depending on the film thickness and surface tensions. A…
We present a model that describes grain-boundary-limited conduction in polycrystalline semiconductors, for thermally assisted ballistic as well as diffusive transport, both for degenerate and nondegenerate doping. In addition to bulk parameters (the carrier effective mass and mean free path) the model contains grain b…