Materials Literature
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We report measurements of the electronic conductivity and partly the electronic mobility and optical absorption spectra in alkali halide melts containing tantalum or niobium chloride and oxychloride complexes in different oxidation states. Both electrochemical impedance spectroscopy and the Wagner–Hebb polarization me…
The first example of monomeric bidentate citrato oxomolybdate(VI) and -tungstate(VI) have been prepared by cleavage of dimeric citrato molybdate and tungstate.
Ten novel columnar liquid crystals, [octakis(4-alkoxyphenyl)tetrapyrazinoporphyrazinato]metal(II) (abbreviated as (C n O) 8 –M; n = 10, 12; M = Cu, Ni) and [octakis(3,4-dialkoxyphenyl)tetrapyrazinoporphyrazinato]metal(II) (abbreviated as (C n O) 16 –M; n = 8, 10, 12; M = Cu, Ni), have been synthesized and characterize…
Two ferrocene-containing low molar mass organosiloxane liquid-crystalline materials have been synthesised and their phase-transition behaviour investigated. The ω-unsaturated ferrocene precursor was hydrosilylated by addition of pentamethyldisiloxane or heptamethyltrisiloxane in the presence of platinum divinyltetrame…
This paper examines the dynamic process of hairiness formation in worsted ring spinning. A special CCD camera was used to observe the fibre behaviour in the spinning triangle. The formation mechanisms of leading, trailing, looped, and wild hairs are demonstrated with a series of photos. Several unique features on hair…
Diazadithiafulvalenes act as excellent electron donors to arenediazonium salts. The diazadithiafulvalenium radical cations trap primary carbon radicals successfully. However, the diazadithiafulvalenium salts which form, undergo rapid ring fragmentation in contrast to their tetrathia counterparts.
A blue luminescent emission band (440 nm) has been optimised in Y1 – xBixNbO (x = 0.005) for low voltage phosphor applications. The material has useful properties when compared to a commercially available phosphor. The role of the Bi3+ ion dopant is discussed in this lattice and in the related Gd1 – xBixNbO4 lattice.…
The first crystal structure of an inorganic pyrophosphatase (S-PPase) from an archaebacterium, the thermophile Sulfolobus acidocaldarius, has been solved by molecular replacement and refined to an R-factor of 19.7% at 2.7 A. S-PPase is a D3 homohexameric protein with one Mg2+ per active site in a position similar to,…
The ground states of La 1- x Ca x MnO 3 change from double-exchange-associated conducting ferromagnets at x <0.50 to charge-ordered antiferromagnets at x >0.50 even when x is varied only slightly around 0.50. We have performed a careful study of the electrical and magnetic properties of these materials for a range of…
We have considered the dynamical evolution of cellular patterns controlled by a stochastic Glauber process determined by the deviations of local cell topology from that of a crystalline structure. Above a critical temperature evolution is towards a common equilibrium state from any initial configuration, but beneath t…
Motivations leading to lowering the primary beam energy in the SEM are summarized and arguments are presented in favour of extending the operation range down to tens and units of eV. Possibilities to produce beams at low energies below 1 keV and very low energies below 50-100 eV are reviewed, particularly the principl…
Based upon thermodynamic considerations, we propose ‘soft, solution processing’, as a means to fabrication of shaped, sized, and controlled advanced materials from aqueous solutions without excess heat, energy consumption, expensive equipment, and precursor(s) as one of the most economical and environmentally friendly…
Two GRADIENT-DEPENDENT COMBINATIONS of isotropic plasticity and scalar damage are proposed. The gradient enhancements of either the plasticity or the damage component of the theory are performed by introducing the Laplacian of a strain measure and an internal length parameter. This makes the constitutive models applic…
Heat treatment at temperatures >835/spl deg/C and compressive stresses >80 MPa substantially increased the magnetostrictive performance of Terfenol-D (Tb/sub 0.3/Dy/sub 0.7/Fe/sub 1.92/) under the condition of zero loading. This heat treatment created a built-in prestress which significantly increased the low stress m…
The modifications induced by excimer laser irradiation of poly(ether ether ketone) (PEEK) surfaces have been investigated as a function of the laser process parameters for laser fluences below the material ablation threshold. In the case of 193 nm laser treatment, a significant increase in the adhesion properties of P…
CdS/CdSe core/sheath nanowires with diameters of 7.7/0.75 nm were prepared by treating CdS nanowires with selenium in tributylphosphine (TBP) at 100 °C for 24 h and were characterized by X-ray powder diffraction, transmission electron microscopy, high resolution TEM, UV–VIS absorption spectra, photoluminescence spectr…
The mechanisms of photoexpansion in As2S3 glass have been studied through the excitation energy dependence. When the glass is exposed to supergap light homega 2.7 eV) in air, photodepression occurs, which is ascribable to photovaporization. In vacuum, the glass always expands. When the glass is illuminated by a weak b…
In order to study electronic and steric effects on δ(103Rh), the103Rh-NMR spectra of a series of [Rh(cod)L2] complexes (with L = nitrogen, oxygen, or chloride) have been measured by gradient-enhanced HMQC (1H,103Rh) NMR spectroscopy. Density functional computations of representative examples have been performed at the…
In chemical vapor deposition (CVD) of copper, adsorption of iodine on the growing film surface greatly suppresses the development of surface roughness such that thick films show a root‐mean‐square roughness and a high specular reflectance of 85% for a laser beam. The films are predominantly (111)‐oriented regardless o…
Three new copper(II) complexes with simple pyrazolate bridges have been prepared, [Cu2(pz)2(dpa)2(H2O)Cl]Cl·H2O 1, [Cu2(pz)2(phen)2Cl2]·2C2H5OH 2 and [Cu2(pz)(phen)2Cl3]·2H2O 3 (Hpz = pyrazole, dpa = di(2-pyridyl)amine, phen = 1,10-phenanthroline) and their crystal and molecular structures determined. The copper centr…