Materials Literature
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The photochromism of spiro[cyclohexadiene-indolines], the reversible bond cleavage at the spiro-carbon resulting in a colored merocyanine, is affected by solvent polarity. Photoexcited intramolecular charge transfer within the preserved spiro form of the molecule is favored in polar solvents, explaining the drop in me…
In this paper, a Stoner-Wohlfarth approach to magnetic hysteresis is used as a model for a ferromagnetic composite rod consisting of single domain `grains' with random orientations embedded in a non-magnetic matrix. The rod is considered to be under torsional stress, which means that the rod at each point on its outer…
Fourier transform-infrared studies have been carried out on the non-stoichiometric Ni-Zr substituted barium hexaferrite synthesized through the citrate precursor method. We observed approximately 30 bands, almost twice as many as reported for stoichiometric samples. These are attributed to the shifting of the vibratio…
The composite structure of glow peak 5 in LiF:Mg,Ti (TLD-100), has been investigated using optical bleaching by 310 nm (4 eV) light. The decay of composite peak 5 and the growth of peak 4 are described by two exponential components of the same mean lives for both peaks. Using computerized glow curve deconvolution and…
To date most of the microelectromechanical system (MEMS) devices have been based on silicon. This is due to the technological know-how accumulated on the manipulation, machining and manufacturing of silicon. However, only very few devices involve moving parts. This is because of the rapid wear arising from high fricti…
Micro-organisms such as bacteria and yeasts form CdS to detoxify toxic cadmium ions. Frequently, CdS particles formed in yeasts and bacteria were found to be associated with specific biomolecules. It was later determined that these biomolecules were present at the surface of CdS. This coating caused a restriction in t…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA General Mechanism for CO Oxidation on Close-Packed Transition Metal SurfacesChangjun Zhang, Peijun Hu, and Ali AlaviView Author Information School of Chemistry The Queen's University of Belfast Belfast BT9 5AG, U.K. School of Mathematics and Physics The Queen's Unive…
The fabrication of micropatterned TiO2 films on deep UV patterned self-assembled monolayers (SAMs) of phenylsiloxane is described. The patterned SAM was immersed in an acidic, aqueous TiF62- solution to directly deposit crystalline TiO2 (anatase) onto both hydrophobic (masked) and hydrophilic (irradiated) surface regi…
Crystal structures of ethylene−vinyl alcohol copolymers (EVOH) with various vinyl alcohol (VA) compositions have been determined on the basis of the X-ray diffraction data measured for the uniaxially and doubly oriented sample specimens. The unit cells of EVOH with a VA content higher than 27 mol % are monoclinic of t…
A monolayer ultrathin film of nitro-containing diazoresin (NDR) was fabricated on mica via a self-assembly technique. The adsorption of NDR on mica at different deposition times was monitored by determining the absorbance of the NDR. It was confirmed that the deposition is rapid and reaches saturation within 2 min. Th…
Polystyrene- block -poly(2-vinylpyridine) with different block lengths, viz., 190−190 and 800−860 monomer units, have been employed in order to obtain monodisperse Au nanoparticles, dispersed in a polypyrrole (PPY) matrix. In consonance with optical absorption spectra, the formation of a nanodispersion of Au has been…
The unsymmetrical dithienylethene photochrome 1a exhibits proton-gated photochromic properties as well as novel chemical reactivity. The dimethoxylated derivative 9a represents a light-triggered proton switch whose dissociation constant is increased by a factor of 16 upon photochemical cyclization to 9b. Such compound…
The synthesis of semiconducting nanocrystals of manganese oxide of controlled sizes and their manipulation to form ordered arrays is described. Nanocrystalline mixed-valent manganese oxides have been prepared as colloidal solutions via reduction of tetraalkylammonium (methyl, ethyl, propyl, and butyl) permanganate sal…
Carbon nanotubes (CNTs) have been proposed as excellent materials for the construction of new, precisely tailored ultrafiltration membranes and as promising fibres for the construction of new, stronger composite materials. In this paper classical molecular dynamics simulations are used to investigate the potential use…
Carbon nanotubes are manipulated in three dimensions inside a scanning electron microscope (SEM). A custom piezoelectric vacuum manipulator achieves positional resolutions comparable to scanning probe microscopes, with the ability to manipulate objects along one rotational and three linear degrees of freedom. This pro…
The alignment of cellulose microcrystals in a 6.9% (w/w) colloidal aqueous suspension under shear was characterized using small angle synchrotron radiation scattering. Prior to shearing, the microcrystals appeared randomly oriented and went through a two-step alignment process with increasing shear rate. At shear rate…
We have reproduced band structure calculations from the literature and have used them to analyze in detail the energy landscape around the Fermi level. We found three Van Hove singularities, two below (-230, -54 meV) and one above the Fermi level (+27 meV). We have studied the composition of each one of them and found…
We examined the steady state and time resolved luminescence spectral properties of two types of CdS nanoparticles. CdS nanoparticles formed in the presence of an amine-terminated dendrimer showed blue emission. The emission wavelength of these nanoparticles depended on the excitation wavelength. The CdS/dendrimer nano…
We demonstrate the tailoring of highly oriented pyrolytic graphite (HOPG) to obtain uniformly sized islands of up to several microns in size. There has already been some research on manipulating individual sheets on HOPG surfaces with scanning probe microscope tips; such sheets were obtained either accidentally or wit…
Here, we report the use of amine-terminated poly(amidoamine) (PAMAM) dendrimers as adhesion promoters between vapor-deposited Au films and Si-based substrates. This method is relatively simple, requiring only substrate cleaning, dipping, and rinsing. Proof of concept is illustrated by coating glass slides and single-c…