Materials Literature
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The overwhelming majority of tilted smectic liquid crystals exhibit synclinic (Sm-C) ordering (a uniform tilt direction in all smectic layers) rather than anticlinic (Sm-C(A)) ordering (a tilt direction that alternates from layer to layer). We propose that polar molecular-scale fluctuations of the interface between sm…
Based on the technology of polymer-dispersed liquid crystals (PDLC), this work deals with the preparation of bifunctional films sensitive to electric fields (changing transparency) and to light (changing color). Contrary to our recently proposed films working in the opaque → transparent way on applying an electric fie…
The spontaneous decay process of an excited atom placed inside or outside a carbon nanotube is analyzed. Calculations have been performed for various achiral nanotubes. The effect of the nanotube surface is shown to increase the atomic spontaneous decay rate by up to 6 orders of magnitude compared with that of the sam…
CMTI-I, a small-protein trypsin inhibitor, has been crystallized as a 4:1 protein-zinc complex. The metal is coordinated in a symmetric tetrahedral fashion by glutamate/glutamic acid side chains. The structure was solved by direct methods in the absence of prior knowledge of the special position metal centre and refin…
Abstract The Bragg regime shifts when conventional materials in a multilayer distributed Bragg reflector (DBR) are replaced by artificial materials with the so‐called negative index of refraction. This provides an avenue for characterizing the latter class of materials. © 2002 Wiley Periodicals, Inc. Microwave Opt Tec…
RNA polymerase holoenzyme from Thermus thermophilus, consisting of six protein subunits (alpha(2), beta, beta', omega and sigma(70)) and having a total molecular mass of about 450 kDa, was purified and crystallized by the hanging-drop vapour-diffusion technique under mild near-physiological conditions. The crystals di…
Chlorination of microbial polyesters poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxyoctanoate) (PHO) was carried out by passing chlorine gas through their solutions. The chlorine contents in chlorinated PHB (PHB-Cl) and chlorinated PHO (PHO-Cl) were between 5.45 and 23.81 wt % and 28.09 and 39.09 wt %, respectively.…
The water phase diagram is extraordinarily complex. In addition to numerous solid phases of ice, studies have pointed to the existence of distinct amorphous phases. It has even been proposed that there may be a liquid-liquid critical point, where two different liquid phases coexist. In his Perspective, Soper highlight…
We report molecular dynamics simulations of the production of radiation cascades in two pyrochlore compounds that have been proposed as possible materials for high level radioactive waste storage. There are clear differences between the two systems that support the results of recent high energy ion bombardment experim…
Reaction of carbaporphyrins 1 with silver(I) acetate in methanol-CH(2)Cl(2) gave excellent yields of the related silver(III) complexes 6. These nonpolar organometallic compounds retain fully aromatic properties as judged by UV-vis and NMR spectroscopy and were further characterized by X-ray crystallography and cyclic…
The one-electron oxidation of ZnT(t-Bu)PP (T(t-Bu)PP2- = 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrin dianion) by one equivalent of Ru(bpy)33+ (bpy = 2,2'-bipyridine) results in quantitative formation of ZnT(t-Bu)PP*+ which is detected by ESR. In the presence of excess ZnT(t-Bu)PP, the ESR line width becomes…
Triblock copolymers in a solvent selective for their middle blocks provide the basis for the formation of novel physical networks in which cross-links are formed by self-assembled domains of the end blocks. Triblock copolymers of poly(styrene)−poly(ethylene butylene)−poly(styrene) (SEBS) dissolved in oil constitute su…
The pair annihilation of straight line defects with strength +/-1/2 in bulk nematic systems is studied numerically, considering a full coupling of orientational degrees of freedom and hydrodynamics. This work is based on the generalization of the Ericksen-Leslie theory to the tensor order parameter as proposed by Qian…
In this study, the feasibility of building a database of theoretical atomic deformation density parameters applicable to the construction of the densities of biomacromolecules and to the interpretation of their X-ray diffraction data is discussed. The procedure described involves generation of valence-only structure f…
The title anion was synthesized by oxidation of nido-Ge94- with Ph3P or Ph3As in ethylenediamine solution. It was structurally characterized in the compound (Rb-2,2,2-crypt)6[Ge9=Ge9=Ge9].3en (2,2,2-crypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) crystallized from the solution. The anion is a linea…
$(\mathrm{TMTTF}{)}_{2}{\mathrm{AsF}}_{6}$ undergoes two phase transitions upon cooling from 300 K. At ${T}_{\mathrm{CO}}=103 \mathrm{K}$ a charge ordering (CO) occurs, and at ${T}_{\mathrm{SP}}(B=9 \mathrm{T})=11 \mathrm{K}$ the material undergoes a spin-Peierls transition. Within the intermediate, CO phase, the char…
The room-temperature syntheses and single-crystal structures of C(4)N(2)H(12).NH(4)Cl(3).H(2)O and C(6)N(2)H(14).NH(4)Cl(3) are reported. These novel molecular perovskites contain vertex-sharing octahedral (NH(4))Cl(6) arrays which replicate the octahedral packing in the cubic (SrTiO(3)) and 2-H hexagonal (BaNiO(3)) p…
Difference in density of states for the spin's majority and minority bands in a ferromagnet changes the electrostatic potential along the domains, introducing the discontinuities of the potential at domain boundaries. The value of discontinuity oscillates with number of domains. Discontinuity depends on the positions…
The decomposition and the reformation of the (Bi,Pb)2Sr2Ca2Cu3O10+d (?Bi,Pb(2223)?) phase have been investigated in-situ by means of High-Temperature Neutron Diffraction, both in sintered bulk samples and in Ag-sheathed monofilamentary tapes. Several decomposition experiments were performed at various temperatures and…
We analyze fulleride superconductivity at experimental doping levels, treating the electron-electron and electron-phonon interactions on an equal footing, and establish the existence of novel physics which helps explain the unusually high superconducting transition temperatures in these systems. The Jahn-Teller phonon…