Materials Literature
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The chemical structure, including changes in charge distribution upon doping, for vapor-deposited polythiophene films has been investigated using x-ray photoelectron spectroscopy (XPS). Two different methods of doping, coevaporation with FeCl3 and exposure to iodine vapor, are contrasted in this study and several chem…
When a soil is flooded, iron (Fe) reduction and methane (CH4) production occurred in sequence as predicted by thermodynamics. The dissolution and precipitation of Fe reflected both soil pH and soil redox potential (Eh). The objective of our experiment was to determine both CH4 production and Fe reduction as measured b…
Cellulose is abundant in nature, with the advantages of low-cost, biodegradable and biocompatible, low density and high strength. However, the development and application of cellulose has been lagging behind its potential due to its unique properties. Cellulose has a large quantity of hydroxyl groups which can easily…
The surface free energy (γ s ) of modified carbon fibers was determined by tensiometry and effects of CF4-O2 plasma treatment were evaluated. The treatment with the gas mixture in which oxygen was above 40% accelerated preferentially the oxidation of fiber surfaces and the nondispersive component of the surface free e…
Dielectric and electrooptic studies of 4′-[(S,S)-2,3-epoxyhexyloxy] phenyl 4-(decyloxy) benzoate (in short EHPDB) have been done and Goldstone mode (GM) and domain mode (DM) relaxation have been observed. The dielectric measurements have been done in the temperature range between 57˚C and 80˚C covering the N*, SmA*, S…
Silicon field emitter arrays have been fabricated and investigated. Four different field emission enhancement layers were studied: (1) porous silicon layers, (2) carbon films, (3) hydrogen implanted layers, (4) Cs-enriched layers. Scanning electron microscopy was used to study the morphology of the tips. Comparison of…
Field emission has been observed from chemical vapor deposited diamond grown on Mo and Si substrates. Emission was observed at fields as low as 20 kV/cm. The samples were tested in the as-grown form, and after coating with thin films of Au, CsI, and Ni. The emission current was typically maximum at the onset of the ap…
The influence of silica content of four styrene-butadiene rubbers on their adhesion to polyurethane adhesives was studied. Untreated rubber shows no adhesion due to a weak boundary layer of zinc stearate. Roughening removed zinc stearate from the rubber surface, increased the surface energy and produced surface roughn…
The oxidation of reduced chlorides (MCl 2 ) or chloride-hydrides (MClH x ) of the lanthanides with sulfur (700-850 °C, 7 d, sealed tantalum capsules or evacuated silica vessels) usually results in the formation of the sesquisulfides M 2 S 3 as the main products. In the presence of appropriate fluxes (e.g., alkali hali…
The measurement of the stress - strain properties of materials at high strain rates is principally carried out using the split Hopkinson pressure bar (SHPB) technique, in which high compressive strain rates, typically in the range , are achievable with small solid discs as the test materials. Torsional SHPB systems ha…
We performed dielectric- and electrooptical measurements of a ferroelectric liquid crystal film as a function of temperature, frequency and bias field. Starting with the homeotropic texture, obtained with a silane coating, we measured the dielectric properties in the direction of the helical axis. After realigning to…
The two databases ICSD and TYPIX are described. ICSD is a comprehensive compilation of crystal structure data of inorganic compounds (about 39 000 entries). TYPIX contains 3600 critically evaluated data sets representative of structure types formed by inorganic compounds.
Abstract A norbornadiene tetracarboxylic acid was synthesized the p K s of which can be changed by irradiation forming the quadricyclane derivative or by catalytical reisomerization to the norbornadiene. The p K s difference of both isomers in the second and fourth dissociation step is 0.59 and 0.68 units. Photochemic…
Abstract The characteristics of hydrated mineral fillers are discussed with reference to their use as fire retardant additives for polymers. Particular consideration is given to their mode of action and criteria which influence their performance, both in reducing polymer flammability and in suppressing smoke evolution…
It is expected that the use of electrical equipment at high temperatures will increase in the future, and the demand for heat-resistant insulation that can be used at temperatures above 300/spl deg/C will increase. In addition, this high temperature electrical equipment will need to be higher in voltage and have a lar…
The effect of chain modification on the transport properties of two types of polyethylene-based polymers is reviewed in this work. Attention is focused on a polyketone terpolymer (0.93 : 0.07 : 1 ethylene/propylene/carbon monoxide) and on an ethylene—acrylic acid ionomer in order to determine their gas and water vapor…
Dealloying of a binary noble alloy produces a porous layer rich in the more noble element. Application of a tensile load initiates a brittle intergranular (IG) crack in the dealloyed layer that advances into the unattacked material. This study showed that the crack penetration depth (Cd) is proportional to the thickne…
Hydride precipitation and dissolution in a zirconium matrix have been simulated numerically using a finite element technique. The evolution of the accommodation energy associated with such phase transformations has been evaluated for isotropic and anisotropic misfitting hydrides in an infinite stress-free body. It was…
The morphology of the carbon nitride (C1−xNx) thin films deposited by the reactive ion beam sputter deposition technique has been studied. A pure graphite target has been sputtered using nitrogen ions. Some of the deposited films have been irradiated with the primary nitrogen ion beam during the deposition. The films…
The surface-induced enhancement of UV–visible absorption and Raman spectra of cyanine dye D266 molecules adsorbed on ZnO colloids is reported. The Raman enhancement factor is estimated to be more than 50. The enhancement mechanisms are discussed. The surface-induced absorption enhancement is the main cause of the Rama…