Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and properties of new poly(dimethylsiloxane) nanocompositesShelly D. Burnside and Emmanuel P. GiannelisCite this: Chem. Mater. 1995, 7, 9, 1597–1600Publication Date (Print):September 1, 1995Publication History Published online1 May 2002Published inissue 1 September…
We carry out a completely first-principles study of the ferroelectric phase transitions in ${\mathrm{BaTiO}}_{3}$. Our approach takes advantage of two features of these transitions: the structural changes are small, and only low-energy distortions are important. Based on these observations, we make systematically impr…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew Sensitizer-Modified Calix[4]arenes Enabling Near-UV Excitation of Complexed Luminescent Lanthanide IonsFrank J. Steemers, Willem Verboom, David N. Reinhoudt, Erik B. van der Tol, and Jan W. VerhoevenCite this: J. Am. Chem. Soc. 1995, 117, 37, 9408–9414Publication Date (P…
A method for solving small-strain plasticity problems with plastic flow represented by the collective motion of a large number of discrete dislocations is presented. The dislocations are modelled as line defects in a linear elastic medium. At each instant, superposition is used to represent the solution in terms of th…
Mesoporous silica molecular sieves have been prepared by the hydrolysis of tetraethylorthosilicate in the presence of low-cost, nontoxic, and biodegradable polyethylene oxide (PEO) surfactants, which act as the structure-directing (templating) agents. This nonionic, surfactant-neutral, inorganic-precursor templating p…
The review deals with the characteristic features of the formation of certain complex perovskite-like oxides. In the crystal structures of these compounds, it is possible to differentiate fragments with different structures, which alternate along the three-fold or four-fold axis of the perovskite sublattice. This appr…
In recent times, optical diffraction and reflection from periodically twisted liquid crystalline media have attracted a lot of attention. The important developments in this area have been considered here.
Thin submicron and micron films of liquid crystals placed between two isotropic media represent a particular example of confined systems. Such films can be prepared on the surface of glycerin or other liquids, In comparison with Langmuir monolayers, these films are macroscopically thick to involve the liquid crystalli…
Abstract New segmented polyurethanes (FPU) with perfluoropolyether (PFPE) blocks have been synthesized by a two‐step process. In the first step, a fluorinated isocyanate end‐capped prepolymer has been obtained by reaction of a fluorinated macrodiol with alicyclic diisocyanates in the presence of solvent. The following…
Synthetic genes encoding recombinant spider silk proteins have been constructed, cloned, and expressed. Protein sequences were derived from Nephila clavipes dragline silk proteins and reverse-translated to the corresponding DNA sequences. Codon selection was chosen to maximize expression levels in Escherichia coli. DN…
We have studied nucleation and growth characteristics of diamond on nickel with AlN buffer layers. The diamond deposits on partially filled 3-d shell transition metals such as Ni, Fe, and Co usually result in the formation of interposing graphite layers which cause poor adhesion of diamond overlayers. To minimize and…
A semiconductor-metal transition occurring just below the Curie temperature T C was observed in single crystals of perovskite La 1-x Sr x MnO 3 for x>or=0.175. For x<or=0.15 the crystals exhibit only semiconducting behaviour. These transport properties are closely connected with the electron transfer mediated by the d…
In combination with scanning electron microscopy and x-ray pole-figure analysis high resolution electron microscope (HREM) observation of the diamond-silicon cross section in a 〈001〉 epitaxially oriented diamond film was carried out to investigate the atomic interfacial microstructure. The films were prepared by micro…
Lithium oxide has been suggested as a suitable breeder blanket material for fusion reactors. Tritium ions and lithium vacancies are created by neutron irradiation, forming bulk defect complexes whose exact character is experimentally unclear. We have used ab initio total energy pseudopotential methods to study the str…
Laser ablation of a BiSrCaCuO target is performed both in vacuum and in an oxygen pressure of 0.1 mbar. Two substrates are located in the chamber in order to study the role of re-emission processes from the growing film and/or the scattering of the ablated species by an oxygen atmosphere. The results indicate that re-…
Electron paramagnetic resonance (EPR), optical absorption, and photoluminescence (PL) spectroscopy have been combined to characterize Pb-doped ZnO ceramic powders. We observe a decrease in the 2.26 eV emission peak and a concomitant smearing of the band edges, narrowing the effective gap of the grains to ≊2 eV with in…
This letter reports, diamond field emitters, Cs treated, air stable, that emit electrons at the lowest reported field, &lt;0.2 V μm−1. Field emission from B-, Li-, P-, and N-doped diamonds and carbonized polymer was characterized as a function of surface treatment. A treated with an O2 plasma, coated with Cs, heat…
The anharmonic lifetimes of zone-center optical phonons in C, Si, and Ge are calculated along with their temperature and pressure dependences, using third-order density-functional perturbation theory. Our basic ingredients are by-products of a standard linear-response calculation of phonon dispersions in the harmonic…
The stability of the flow in a half-zone configuration is analysed with the aid of direct numerical simulation. The work is concentrated on the small Prandtl numbers relevant for typical semiconductor melts. The axisymmetric thermocapillary flow is found to be unstable to a steady non-axisymmetric state with azimuthal…
Self-condensing vinyl polymerization was used to produce dendritic polymers with both highly branched structures and numerous reactive groups. A vinyl monomer will undergo self-polymerization if it contains a pendant group that can be transformed into an initiating moiety by the action of an external stimulus. The sel…