Materials Literature
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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…
The mixed perovskite Sr 2 FeNbO 6 has been shown to have a tetragonal structure with space group I 4/ m (87), a = 5.6078(1) Å, c = 7.9658(1) Å, V = 250.51(1) Å 3 according to electron and X-ray diffraction. The material is redox stable and maintains its structure in a reducing atmosphere. After reducing in 5% H 2 at 9…
Abstract In order to understand the formation of different crystal structures and improve the mechanical properties of isotactic polypropylene (iPP), melt vibration technology, which generally includes shear vibration and hydrostatic pressure vibration, was used to induce the change of crystal structure of iPP. iPP fo…
In single- or multi-wavelength anomalous dispersion (SAD/MAD) phasing, one of the essential steps is to find the absolute configuration (hand) of the anomalous scatterers. A computer program, ABS , based on an algorithm proposed by Woolfson & Yao [ Acta Cryst . (1994), D 50 , 7–10] has been written to determine th…
Abstract A numerical simulation model that incorporates three phases, polymer matrix, interlayer, and clay platelet, was developed to predict the tensile modulus of nanoclay‐filled polymer composites. The interlayer was introduced to account for the fact that the mechanical properties of the polymer near the clay surf…
The role of polymer charge density in the kinetics of the adsorption and desorption, on silica, of the polyelectrolyte poly(ethyleneimine) (PEI) was investigated by stagnation-point flow reflectometry. In the first series of experiments, PEI solutions were introduced at the same ionic strength and pH as the background…
This study provides conclusive proof that the thermally excited open-shell state with biradical character is contributing to the ground state of a closed-shell molecule, tF-BDPI-2Y, where four hydrogen atoms at the central phenylene ring are substituted with four fluorine atoms of 1,4-bis-(4,5-diphenylimidazol-2-ylide…
Improved methods for indexing diffraction patterns from macromolecular crystals are presented. The novel procedures include a more robust way to verify the position of the incident X-ray beam on the detector, an algorithm to verify that the deduced lattice basis is consistent with the observations, and an alternative…