Materials Literature
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The optical properties of Er3+ ions doped in aluminate glasses were investigated.(1) Among three intensity parameters obtained from absorption spectra by Judd-Ofelt theory, Ω2 and Ω4 showed a large value compared with those in other oxide glasses.(2) The multiphonon decay rates of the 4S3/2 and 4F9/2 levels were obtai…
Two mutants of adenylate kinase from Escherichia coli have been crystallized and analyzed by X-ray diffraction at resolutions of 3.4 and 2.4 A, respectively. These mutants are Pro-9-->Leu and Gly-10-->Val. They were selected for their positions in the highly conserved Gly-loop forming a giant anion hole for the beta-p…
The influence of elevated copper concentrations on cell numbers and extracellular protein production was investigated in chemostat cultures of Vibrio alginolyticus. High (20 microM) copper in the medium reservoir resulted in a dramatic drop in cell numbers which was overcome with time. The copper-stressed cultures est…
Abstract The initial oxidation behaviour of a Co–20%Ni alloy exposed to air and the longer term oxidation of a metalevaporated magnetic recording tape (MET) of the same composition have been studied using XPS and AES. Air exposure of the alloy for 24 h showed the formation of a mixed hydroxide/carbonate layer over a r…
The brittle-ductile transition (BDT) in precracked Si and other pure covalent crystals is associated with plastic relaxation processes induced by the crack tip stress field. A model which simulates the dynamic behaviour of shielding dislocations near a crack tip under an increasing stress has been developed. Dislocati…
The mixed perovskite La2CuTiO6 has been prepared using several methods (classical ceramic, oxide precursors and sol–gel) in order to study the distribution of Cu and Ti in the lattice. This perovskite has an orthorhombically distorted structure [Pnma, standard group no. 62, a= 5.6262(6)Å, b= 7.8396(8)Å, c= 5.5702(6)Å,…
Singlet excited-state properties of mono- and di-thiaporphyrins and their dications are reported. A comparison of vibrational frequencies of the ring stretching modes of neutral and protonated species in resonance Raman spectra show shifts to both higher and lower frequencies. An analysis of the shifts of various Rama…
The authors present a review of their research work in an endeavor to interpret the behavior of zinc-rich paints (ZRP) using electrochemical impedance spectroscopy (EIS). This technique can provide much useful information about the protection mechanisms of ZRP. The tendency of some of these coatings to act like an ele…
After a brief review of the experimental data concerning phase transitions in ferroelectric thin films, a theoretical treatment based on the Landau-Devonshire expansion is presented. A surface is characterised by a length δ, the negative of the logarithmic derivative of the order parameter at the surface. For negative…
The mechanism of the ω→α phase transformation following isothermal aging has been studied on a single crystal of a Ti-14 mass%Mo alloy. For isothermal aging at 623 K, the specimen showed a maximum hardness at 1×106 s and subsequent softening. At 3×105 s to 1×106 s the ω particle abruptly grew so far as about 100 nm by…
Abstract The electrochemical behaviour, FTIR spectrum and the morphology of polypyrrole‐polystyrenesulphonate (PPy‐PSS) films obtained potentiostatically at 0.6 V in a 0.05m Py + 1.7 × 10 −2 m NaPSS medium have been analysed. Different electrochemical parameters have been modified in order to establish the first polar…
This paper describes the results of accelerated particulate fouling tests performed on different enhanced tubes and a plain tube. The key purpose of the tests was to investigate particulate fouling in practical heat exchanger systems where a mixture of particles exists in a flowing water stream. The applications consi…
The new lanthanide–hydrogen–transition metal compounds [{[PMe3)3WH5}2Yb·L3] and [{(η-C5H5)2NbH2}2Yb·L3], where L3=(MeOCH2CH2)2O, are prepared and their crystal structures determined.
Several clean agricultural screens were tested to determine force and static pressure drop across the screen created by airflow through the screen. Wind pressures on screens and static pressure drop across screens increased exponentially with increases in apparent air velocity. Fabric density, configuration, and dimen…
The hydrolytic behaviour of iron(III) has been investigated. The infrared spectrum of the sulfate salt of a hydrolysed iron(III) solution was found to match that of a gallium sulfate that had been shown through magic angle spinning NMR spectroscopy in combination with powder X-ray diffraction studies to contain the Ga…
Water vapour was used as a diffusional probe to study segmental mobility in hydrogen-bonded polymer blends. Modified polystyrenes containing 4-hydroxystyrene as comonomer units were blended with poly(methyl methacrylate). The diffusion coefficient of water decreased with increasing concentration of the diffusant. Clus…
A new direct-methods procedure has been devised which consists of phase refinement via the minimal function, R(phi), alternated with Fourier summation and real space filtering. All phases are initially assigned values by computing structure factors for a randomly positioned set of atoms. These phases are then refined…
Currently, there are a large variety of degradable polymers available for use in surgery, which are generally based on blends and copolymers of poly(L-lactide) (PLLA) and poly(L-glycolide) (PGA). The major demand for these materials is for suturing of wounds, but the materials are also being developed for use in ortho…
The (R4N)2[Ni(tdas)2] complexes (tdas2–= 1,2,5-thiadiazole-3,4-dithiolate and R = Bu, Et) are prepared and characterized by X-ray crystallography, which reveals differences in their structure dependant on the size of the R4N cation.
Partial discharge measurement is an important means of assessing the condition and integrity of insulation systems in high voltage power apparatus. Commercially available partial discharge detectors display them as patterns by an elliptic time base. Over the years, experts have been interpreting and recognising the na…