Materials Literature
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The effect of sintering atmosphere on the final density and electrical properties of alumina compacts has been investigated using two different oxygen pressures: air and CO/CO 2 . Measuring of electrical behavior has been considered a tool for determining the mechanism responsible for densification. Finally, the impor…
The mechanism of material removal from SiC by CO 2 laser heating was studied using sintered and single‐crystal α‐SiC. Removal rate and width of the groove showed maxima when plotted as a function of translation speeds. Groove depth decreased as the translation speed of samples increased. Similar results were obtained…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNuclear Overhauser effect in solidsJeffery L. White and James F. HawCite this: J. Am. Chem. Soc. 1990, 112, 15, 5896–5898Publication Date (Print):July 1, 1990Publication History Published online1 May 2002Published inissue 1 July 1990https://pubs.acs.org/doi/10.1021/ja00171a0…
Abstract A kinetic model of the homogeneous anionic polymerization of 1,4‐divinylbenzene (1,4‐DVB) in dilute solutions with instantaneous initiation and without cyclization and termination reactions is proposed. The monomer and pendant vinyl group conversions, degrees of polymerization of the primary chains and the cr…
Abstract Poly[2,2'‐(m‐phenylene)‐5,5'‐bibenzimidazole] (PBI) is shown to be miscible with poly(4‐vinyl pyridine) over the entire composition range. Experiments were performed with commercial PBI as well as a lower molecular weight material synthesized by us. Blend miscibility is evidenced by single glass transition te…
A sample of (U,Pu)-mixed oxide was fission heated along the saturation line and into the compressed liquid regime. The density of the sample at temperatures around 7000 K was determined from the onset of the liquid-phase pressure signal. Values for the compressibility of the (U,Pu)-mixed oxide were determined from the…
Abstract Surface analytical and optoelectrochemical measurements were used to clarify the ionic, spectral and electronic changes during oxidation in 3 N NClO 4 of electrochemically formed polycarbezole. The differences in band structure at various potentials could be shown using XPS and UPS measurements. Apart from a…
Existing capabilities to quantitatively model carbide precipitation and sensitization development in austenitic stainless steels are assessed and critically analyzed. A theoretically based, empirically modified model is described that predicts carbide nucleation kinetics, chromium depletion characteristics, and materi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoresponsive ionic conductivity of polymer composite films containing azobenzene liquid crystalKeiichi. Kimura, Tatsuya. Suzuki, and Masaaki. YokoyamaCite this: J. Phys. Chem. 1990, 94, 15, 6090–6093Publication Date (Print):July 1, 1990Publication History Published online…
Optical and dielectric studies of sodium niobate crystals have been carried out in an extended electric field (up to 2.2·108 V/m) at temperatures from 8 0 K to 530 K. It has been found that apart from the known ferroelectric Palma phase, a ferroelectric phase of tetragonal symmetry is induced in NaNbO3 crystals by a s…
A major deficiency of current photon calculation methods that are based on the concept of primary and scatter separation is their inability to handle the condition of electronic disequilibrium. This deficiency is examined and it is shown that the limitation is not inherent in the algorithms themselves but is, at least…
Abstract 2 H and 13 C NMR techniques were used to investigate the thermodynamic state of water molecules and of poly(vinyl alcohol) (PVA) chain segments in frozen 10% PVA solutions in 99.8% and 8.5% 2 H 2 O in the ‐66 to 3°C temperature range. The minimum amount of water not entering into the structure of ice is shown…
Abstract In the development of advanced composite materials, the mechanical behavior of the matrix is of critical importance. The next generation of composite materials will be based on high modulus tough matrices, of which poly(aryl ether ether ketone) [hereinafter, referred to as PEEK] is one of the first crystallin…
R ‐curve measurements were performed on a SiC whisker/Al 2 O 3 matrix composite. A controlled flaw/strength technique was utilized to determine fracture resistance as a function of crack extension. Rising R ‐curve behavior with increasing crack extension was observed, confirming the operation of wake toughening effect…
Abstract Erstmals wurde K 3 [FeO 4 ] durch Tempern inniger Gemenge der Oxide (K 2 O 2 und KFeO 2 mit K 2 O 2 :KFeO 2 = 1,78:1,0, Ag‐Bömbchen, 470°C, 18 d, 350°C, 5 d) in Form von schwarzen, orthorhombischen Kristallen erhalten: Raumgruppe Pnma mit a = 770,16(13) pm, b = 909,20(17) pm, c = 783,70(14) pm. Die Struktur w…
We demonstrate that texture effects can seriously distort the measurement of x-ray-absorption data from powdered specimens. We show that the isotropic average dipolar x-ray-absorption spectrum can always be measured irrespective of the degree of texture, provided axial symmetry in the particle distribution function ex…
Abstract In the flexible packaging industry, aluminium foil is used to fabricate metal–polymer complex systems without any prior surface treatment (e.g. anodic oxide, chemical conversion coating). The inevitable delay between foil rolling and subsequent application of the polymer, in this case polyethylene, allows age…
Effective boundary conditions are derived to be used with the classical Hele–Shaw equations in calculating the shape and motion of a Hele–Shaw bubble. The main assumptions of this analysis are that the displaced fluid wets the plates, and that the capillary number Ca and the ratio of gap width to characteristic bubble…
Abstract The normal incidence electron gun of the IMS4f is unique in design, allowing self‐compensation of electric charges when negative secondary ions are analysed. This is made possible owing to the formation of a cloud containing an excess of very‐low‐energy electrons above the sample surface. When positive charge…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT10-Methylacridine dimer acting as a unique two-electron donor in the one-electron reduction of triphenylmethyl cationShunichi Fukuzumi, Toshiaki Kitano, and Masashi IshikawaCite this: J. Am. Chem. Soc. 1990, 112, 14, 5631–5632Publication Date (Print):July 1, 1990Publication…