Materials Literature
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New cyclophosphazene derivatives incorporating five different mesogenic moieties have been synthesized and their liquid crystalline behaviour has been studied by DSC and polarizing optical microscopy. Smectic A and unclassified smectic 1 phases have been found for the first time in these cyclotriphosphazene derivative…
Gas separation membranes can be physically or chemically modified to improve their separation characteristics. The ability of bromine to form charge-transfer complexes with unpaired electrons along a polymer backbone was utilized to tailor the gas separation properties of a polysulfone membrane. It was hypothesized th…
Recrystallisation in commercial purity aluminium following different strain paths has been investigated. The deformation was carried out using torsion, compression, fully reversed torsion, and torsion followed by compression along the torsion axis, the latter combination giving an orthogonal change in straining state.…
Nylon 6 film quenched from the molten state into liquid nitrogen exhibits an electric displacement vs electric field hysteresis loop at room temperature with the remanent polarization of 26 mC/m 2 , as well as an exothermic anomaly around 340 K in the specific heat due to the heating process, which is attributed to th…
Radiation-induced precipitates on dislocation loops in low and high purity Fe-9, -18 and -50 % Cr alloys were examined under electron irradiation in a high voltage electron microscope operated at 1 MV. Two types of dislocation loops on {100} planes with a <100> Burgers vectors and on {111} planes with a /2<111> are fo…
Abstract This paper examines the use of selected solvents in degreasing, cold cleaning and spot cleaning applications in the aerospace industry, with emphasis on Federal facility operations. Research referenced in this paper is drawn from aerospace industry participants and from research conducted under the Strategic…
The objective of the work reported here was to characterize the tarnish products formed on copper during the early stages of exposure to moist air with trace levels of pollutant gas, in particular hydrogen sulfide and sulfur dioxide/hydrogen sulfide. As determined by x‐ray photoelectron spectroscopy and coulometric re…
A modified split Hopkinson torsional bar (SHTB) is introduced to eliminate the effect of the loading reverberation of the standard SHTB on the study of evolution of shear localization. The effect, the cause and the method by which to eliminate loading wave reverberation are carefully analysed and discussed. By means o…
Ferroelectric PZT thin films were fabricated by metal-organic decomposition (MOD) onto Pt/Ti/SiO2/Si substrates. Different metals (i.e., noble metals: Pt, Ag, and non-noble metals: Al, Cr, In) were selected for top electrodes on PZT thin films. Capacitors with noble metals as top electrodes exhibited symmetric P-E hys…
The low-temperature phase transitions of ${\mathrm{LiK}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Rb}}_{\mathit{x}}$${\mathrm{SO}}_{4}$ mixed crystals have been studied by Raman spectroscopy (x=0.10 and 0.50) and birefringence measurements (x=0.10, 0.20, and 0.50). The mixed compounds with low Rb concentration u…
A recently developed spectroscopic technique was used to determine oxygen diffusion coefficients as a function of temperature for polystyrene and polycarbonate films. Data were recorded at total pressures <300 Torr over the temperature range 5–45 °C under conditions in which argon, helium, and nitrogen, respectivel…
Mandarins were coated with SemperfreshTM and JonfreshTM edible coatings. the weight gain of mandarins after application of Jonfresh and Semperfresh coatings was 0.8% and 0.6% respectively. Weight loss, respiration rate, ascorbic acid, soluble solids (brix) and acidity changes of coated mandarins were compared with unc…
Abstract Callicladol, a novel brominated metabolite has been isolated from Laurencia calliclada Masuda sp. ined., a Vietnamese species of the red algal genus Laurencia. Its structure was deduced from spectral and chemical evidence.
A method is proposed for the solution of the phase problem at very low resolution for macromolecules. It generates randomly a very large number of models, each consisting of a few (two to ten) pseudo-atoms. The corresponding amplitudes are used for selecting a subset of 'best' models by choosing those with the highest…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFree Structure Confinement of Diblock Copolymer MultilayersP. Mansky and T. P. RussellCite this: Macromolecules 1995, 28, 24, 8092–8095Publication Date (Print):November 1, 1995Publication History Published online1 May 2002Published inissue 1 November 1995https://pubs.acs.org…
Abstract Microbial layers on interfaces, called “biofilms” are characterized by a polymeric, highly hydrated gel matrix of microbial origin in which the organisms are embedded and immobilized. Biofilms exhibit degradation behaviour different from that free cells and accumulate water, metabolites, and sorbe substances…
Electronic structure calculations have been employed to study the associative desorption of preadsorbed atomic oxygen from a calcium oxide (100) surface. Two reaction mechanisms were considered, corresponding to symmetric and asymmetric reaction paths. The energy barrier of the latter was found to be the lower of the…
Abstract. The ductility of ultra-high purity copper at elevated temperatures was investigated: purity 99.9999% (6N) and 99.999999 % (8N). Tensile tests were conducted at temperatures ranging from 293K to 1073K at strain rates of 4.2~10- ~ s-l in a high vacuum. The results are discussed in comparison with those for 99.…
An analysis of the dynamic behavior of polymeric liquid crystals is given in terms of a second-rank order parameter tensor describing the orientational state of the local microstructure. The continuum equations governing the dynamics of the material are analyzed under both steady-state and transient conditions for iso…
Polarization-selective gratings are designed by use of rigorous electromagnetic diffraction theory. The polarizing effects are attained by special surface-relief structures. We present a scheme for coding two different optical functions in one diffractive element. It is based on a combination of the scalar diffraction…