Materials Literature
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We describe the properties and construction of a polarization-independent Fresnel lens array using nematic liquid crystals in which the diffraction efficiency of lenses can be electrically controlled. A novel structure is used such that the principal axis of the liquid crystals in two adjacent zones of each Fresnel le…
Abstract Die neuartigen Verbindungen Na 6 [V 18 O 42 H 9 (VO 4 )] s· 21 H 2 O, (NH 4 ) 8 [V 18 O 42 (SO 4 )] · 25 H 2 O, K 6 [V 15 As 6 O 42 (H 2 O)] · 8 H 2 O, (NH 4 ) 6 [V 14 As 8 O 42 (SO 3 )],(NH 4 ) 6 [V 14 As 8 O 42 (SO 3 )], (NH 4 ) 6 [V 14 As 8 O 42 (SO 4 )] und [N(CH 3 ) 4 ] 4 [V 14 As 8 O 42 (H 2 O)] wurden…
The extent to which the librations of rigid molecules can model the crystallographic temperature factor profiles of proteins has been examined. For all proteins considered, including influenza virus hemagglutinin, glutathione reductase, myohemerythrin, myoglobin, and streptavidin, a simple 10-parameter model [V. Schom…
The values of the R-Co exchange field ${\mathit{H}}_{\mathrm{ex}}$ and the crystalline-electric-field parameters ${\mathit{A}}_{\mathit{n}}^{\mathit{m}}$ at the rare-earth (R) site in R${\mathrm{Co}}_{5}$ (R=Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er) and ${\mathrm{Y}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Nd}}_{\mat…
Titanite can incorporate minor amounts of radioactive impurity components (particularly U and Th) that affect the crystal structure by ɑ- and β-decay events; in particular, \nɑ-decay gives rise to significant knock-on structural damage by causing atomic displacements. We have examined a series of chemically and st…
Using the self-consistent-field molecular-orbital theory and the density-functional approximation, we show that vanadium could become magnetic if its size and dimension were constrained. This is illustrated for vanadium forming clusters with body-centered-cubic (bcc) geometry as well as for linear chains. The magnetic…
An alternative mathematical description of thermally stimulated luminescence (TL) and thermally stimulated conductivity (TSC) is presented without the restrictions of the quasiequilibrium (QE) and kinetic-order (KO) approximations. The development is carried out within the framework of a model consisting of a single a…
The solubility of cyclosporin A was determined in water and in Sorensen buffers at pH 1.2 and 6.6 at temperatures ranging from 5 to 37 degrees C. No differences in solubility behaviour were observed among the three aqueous media. Solubility was found to be inversely proportional to the temperature in each medium, indi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCoil-globule type transitions in polymers. 2. Theory of coil-globule transition in linear macromoleculesT. M. Birshtein and V. A. PryamitsynCite this: Macromolecules 1991, 24, 7, 1554–1560Publication Date (Print):April 1, 1991Publication History Published online1 May 2002Pub…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDawson type heteropolyanions. 1. Multinuclear (phosphorus-31, vanadium-51, tungsten-183) NMR structural investigations of octadeca(molybdotungstovanado)diphosphates .alpha.-1,2,3-[P2MM'2W15O62]n- (M, M' = Mo, V, W): syntheses of new related compoundsMostefa Abbessi, Roland C…
The most highly oxidized polyaniline, in the form of pernigraniline base, can be synthesized as an analytically and oxidatively pure solid (powder or large free-standing films) by the controlled oxidation of emeraldine base by m-chloroperbenzoic acid or directly from aniline by oxidative polymerization with (NH4)2S2O8…
Electrochemical techniques such as: corrosion and critical pitting potential measurements, direct current potentiostatic and potentiodynamic polarization, linear polarization resistance, split-cell current measurements, electrochemical impedance, electrochemical noise, and electrical resistance probes are evaluated fo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCp*MoO2Cl-catalyzed epoxidation of olefins by alkyl hydroperoxidesMary K. Trost and Robert G. BergmanCite this: Organometallics 1991, 10, 4, 1172–1178Publication Date (Print):April 1, 1991Publication History Published online1 May 2002Published inissue 1 April 1991https://pub…
A transformer model which consists of a nonlinear core with hysteresis and multiple windings is described as implemented in DSPICE. In contrast to previous implementations, the nonlinear behavior of the new model is described by continuous piecewise-hyperbolic functions characterized by three parameters. These paramet…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLight-scattering study of starlike polymeric micellesLena J. M. Vagberg, Kathleen A. Cogan, and Alice P. GastCite this: Macromolecules 1991, 24, 7, 1670–1677Publication Date (Print):April 1, 1991Publication History Published online1 May 2002Published inissue 1 April 1991http…
The quasi-one-dimensional (1D) conductor ${\mathrm{K}}_{0.3}$${\mathrm{MoO}}_{3}$ undergoes a Peierls transition at ${\mathit{T}}_{\mathit{c}}$=183 K. Using cold-neutron scattering, we have succeeded in resolving in frequency and for wave vectors parallel to the chain direction the pretransitional dynamics and the col…
The glass transition length scale determined from formulae of a fluctuation approach (2ξ a = 2 ... 5 nm) is confirmed by two independent experimental methods. Firstly the glass transition parameters in self-organized amorphous layers of variable thickness in semicrystalline poly(ethylene terephtalate) show significant…
Abstract Weathered perthite and mixed muscovite-kaolinite from a kaolinitic granite at Trial Hill in east Queensland and kaolinized sericitic alteration from a granite from the Ardlethan Tin Mine of New South Wales were examined by optical, scanning electron (SEM), and transmission electron microscopy (TEM) to determi…
Nanocrystalline solids are polycrystals, the crystal size of which is a few (typically 1 to 10) nanometres so that 50% or more of the solid consists of incoherent interfaces between crystals of different orientations. Solids consisting primarily of internal interfaces represent a separate class of atomic structures be…
A minimum exists in the electrical conductivity of the perovskite-type ceramic ${\mathrm{LaCr}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$${\mathrm{O}}_{3}$ as a function of Mn content near x=0.05. This minimum has been explained in terms of a crossover from multiple trapping to percolation amon…