Materials Literature
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The α-Keggin ions [TNb12O40]16− (T=Si, Ge) have been synthesized hydrothermally as water-soluble sodium salts. These clusters are very highly charged, and are bound to their charge-balancing sodium atoms in the solid state (see picture). NMR spectroscopy experiments show that the sodium atoms remain strongly associate…
The synthesis of well-defined luminescent organoboron polymers via a novel three-step procedure starting from silylated polystyrene is reported. Highly selective borylation of poly(4-trimethylsilylstyrene) (PS-Si), followed by replacement of the bromine substituents in poly(4-dibromoborylstyrene) (PS-BBr) with substit…
We have first succeefully synthesized the sodium cobalt oxyhydrate superconductors using KMnO4 as a de-intercalating and oxidizing agent. It is a novel route to form the superconductive phase of NaxCoO2.yH2O without resorting to the commonly used Br2/CH3CN solution. The role of the KMnO4 is to de-intercalate the Na+ f…
In strong-coupling superconductors with a short electron mean free path the self-energy effects in the superconducting order parameter play a major role in the phonon manifestation of the point-contact spectra at above-gap energies. We compare the expressions for the nonlinear conductivity of tunnel, ballistic, and di…
An expression is derived for the strain energy of a polymer chain under an arbitrary three-dimensional deformation with finite strains. For a Gaussian chain, this expression is reduced to the conventional Moony--Rivlin constitutive law, while for non-Gaussian chains it implies novel constitutive relations. Based on th…
Single receptor-ligand bonds have finite lifetimes, so that biological systems can dynamically react to changes in their environment. In cell adhesion, adhesion bonds usually act cooperatively in adhesion clusters. Outside the cellular context, adhesion clusters can be probed quantitatively by attaching receptors and…
Slow relaxation of the magnetization reveals the single-molecule magnetic behavior of [Mn2(saltmen)2(ReO4)2] (saltmen2−=N,N′-(1,1,2,2-tetramethylethylene)bis(salicylideneiminate), a simple, out-of-plane MnIII dimeric complex containing a [MnIII(μ-O)2MnIII] core (see structure shown, Mn brown, O red, N blue, Re pink).…
The optical absorption spectrum of the carbon (4,2) nanotube is computed using an ab initio many-body approach which takes into account excitonic effects. We develop a new method involving a local basis set which is symmetric with respect to the screw-symmetry of the tube. Such a method has the advantages of scaling f…
A new synthetic route to poly-3,4-ethylenedioxythiophene (PEDT) with a conductivity exceeding 1000 S/cm is described. The method is based on base-inhibited vapor-phase polymerization, where a surface covered with ferric p -toluenesulfonate as oxidant mixed with a volatile base (pyridine) is exposed to 3,4-ethylenediox…
The computer program JECP/SP, written in Java, for generating stereographic projections, possesses additional functionality applicable to specimen orientation adjustment using the specimen holder in transmission electron microscopy (TEM). The extension can be used to minimize the difficulties encountered when tilting…
The traditional way of measuring intensities in surface X-ray diffraction experiments is by performing rocking scans. Owing to experimental time limitations, this rather slow procedure leads to incomplete data sets for large surface unit cells. This lack of information not only may affect adversely the accuracy of the…
The influence of molecular weight between cross-links, M c, on the segmental α-relaxation of polybutadiene (PBd) networks was probed using dynamic mechanical spectroscopy. Linear polybutadiene ( M w = 154 kg/mol; M w / M n = 1.10; 60% vinyl) was thermally cross-linked to yield a series of networks encompassing the ext…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTFormation and Characterization of Water-Soluble Platinum Nanoparticles Using a Unique Approach Based on the Hydrosilylation ReactionJunchao Huang, Chaobin He, Xueming Liu, Yang Xiao, Khine Yi Mya, and Jianwei ChaiView Author Information Institute of Materials Research and Engin…
This paper presents a comprehensive methodology for the fitting of site charge models to molecular electrostatic fields computed using quantum mechanical calculations. Charges may be placed both at atomic positions and at “satellite” positions associated with selected atoms. The positions of these satellites is also o…
Abstract The effects of physical aging on the solubility, diffusivity, and permeability of propane and n ‐butane in a hydrocarbon‐based disubstituted polyacetylene, poly(4‐methyl‐2‐pentyne) (PMP), were studied. As the relative pressure of propane and n ‐butane increased, the solubility of both hydrocarbons increased.…
We have investigated how the spin state of an acceptor influences the photophysical processes in a donor-bridge-acceptor (D-B-A) system. The system of choice has zinc porphyrin as the electron donor and high- or low-spin iron(III) porphyrin as the acceptor. The spin state of the acceptor porphyrin is switched simply b…
The Protein Data Bank (PDB) is the single most important repository of structural data for proteins and other biologically relevant molecules. Therefore, it is critically important to keep the PDB data, as much as possible, error-free. In this study, we have analyzed PDB crystal structures possessing oligonucleotide/o…
ESR, IR, optical absorption and photoluminescence spectra of Ho3+ doped tungsten phosphate glasses modified with three different modifier oxides viz., PbO, ZnO and CaO have been studied. The ESR spectral studies indicate tungsten ions are present in W5+ state in all the three glasses with the highest concentration in…
A durable water repellent, stain resistant or flame retardant character can be conferred to polyacrylonitrile (PAN) textiles by using the plasma induced graft polymerization technique. The monomers used are perfluoroalkylacrylate, (meth)acrylate phosphates, and phosphonates which are well known to be effective for the…
Polarization rotation of field-induced phase transformations was observed by means of a polarizing microscope on a (001)-cut single crystal $\mathrm{Pb}({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}{)}_{0.76}{\mathrm{Ti}}_{0.24}{\mathrm{O}}_{3}$ (PMNT24%) at room temperature with an electric field applied along the [001] dir…