Materials Literature
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Other| February 01, 1996 Ordering of the stacking sequence in cookeite with increasing pressure; an HRTEM study Michel Jullien; Michel Jullien Ecole Normale Superieure, Laboratorie de Geologie, Paris, France Search for other works by this author on: GSW Google Scholar Alain Baronnet; Alain Baronnet Search for other wo…
For almost a century now the phenomenon of stress corrosion cracking (SCC) has intrigued many but still continues to excite scientific controversy. This process can cause catastrophic failure in normally ductile alloys and is of serious engineering concern. Of particular importance is the case of transgranular (T) SCC…
We examine entanglements using monomer contacts between pairs of chains in a Brownian-dynamics simulation of a polymer melt. A map of contact positions with respect to the contacting monomer numbers (i,j) shows clustering in small regions of (i,j) that persists in time, as expected for entanglements. Using the ``space…
Abstract In Northwestern Mexico, the Miocene basins that disrupted the Sierra Madre Occidental Province are filled with sandstones and conglomerates (the Báucarit Formation) cemented mainly by zeolites of the heulandite-clinoptilolite group. Few volcanic tuffs are intercalated in the sediments for which four different…
Abstract The compatibility of blends of poly(2‐ethyl‐2‐oxazoline) (PEOX) with poly(2‐hydroxyethyl methacrylate) (PHEMA) and poly(2‐hydroxypropyl methacrylate) (PHPMA) was investigated by means of differential thermal analysis and infrared spectroscopy. Calorimetric results show single glass transition temperatures in…
The surface properties of polycaprolactone (PCL)–poly(ethylene glycol) (PEG) block copolymer (PCE) and blend (B-PCE) of PCL and PEG obviously affect the drug release behavior of the polymer. In this paper, both surface properties of PCE and B-PCE are studied and compared by measuring their water sorption and using the…
Linear polyurethane, linear segmented polyurethane, polyurethane networks, and polyurethane acrylate networks of various composition were synthesized. The variation of Tg with the type of macrodiol, its length, and the chemical composition of the polymer were studied in relation with the percentage of soft segments, t…
All articles of this category A new synthesis of a monofunctionalized β-substituted alkyl porphyrin, 2-(methoxycarbonylethyl)-8,12,13,17-tetraethyl-3,7,18-trimethyl porphyrin ( 1 ), is described. It involves the use of a novel ‘3+1’ connectivity approach. Specifically, the mono-substituted tripyrrane, 2,5-bis(5-carbox…
Potential‐pH diagrams are presented for the systems and . It is shown that the stability field of elemental silicon lies well below the water stability region, indicating that silicon is highly unstable in water relative to oxidation to Si(IV). Thus, the ability to suppress oxide formation must be attributed to kineti…
Polycrystalline oxide fibers have not yet been exploited to their full potential, perhaps because of difficulties with processability. In the successful new route for the production of continuous yttria‐stabilized zirconia fibers detailed here, ZrO 2 particles sols are used as oxide‐forming components. The fine‐graine…
The hardfacing industry has matured substantially since its inception in the early 1920s. Numerous welding alloys have been developed and field proven. By developing a strong working knowledge of available alloys, wear conditions and the specific wear situation, the goal of selecting the proper alloy to prolong servic…
Poly(acrylic acid) (PAA) was decarboxylated in aqueous solution as a function of pH and ionic strength in the temperature range 100–350°C. Degradation kinetics were first order with respect to acid functionality. The rate of decarboxylation at high pH (Eα = 51.1 kcal/mol) was much slower than that at low pH (Eα = 20.3…
Abstract The mechanical behavior of a polyamide 12 is characterized using a viscoplastic law taking into account viscoelastic deformation. Experimental determinations are performed at constant and very low strain‐rates in isothermal conditions during tensile tests. A finite elements code, based on this behavior, enabl…
<div class="htmlview paragraph">Reduction in NOx in light and medium duty diesel engines, without the requirement for Catalyst Converter or Exhaust Gas Recirculation (EGR) and meeting the U.S. emission standards is an important challenge. This paper shows how injection rate shaping should be performed to reduce…
A by-product of phosphate fertilizer production is phosphogypsum (PG). Relatively high F concentrations occur in the solid phase and in the highly acidic process water (PW) that initially fills its pores. The present research addresses the fate of F and the effects on mineral stability as phosphogypsum leachate (PGL)…
We have investigated the temperature, pressure, and field dependence of the spin density wave (SDW) transition in the organic superconductor (TMTSF${)}_{2}$${\mathrm{PF}}_{6}$ and derived parameters for this transition. The SDW can be characterized by the degree to which the two Fermi surfaces couple or ``nest'' as me…
The crystal structure of a 2M 1 muscovite has been refined by the Rietveld method using X-ray powder-diffraction data collected in reflection and transmission geometries, and compared with the results of single-crystal structure-refinement and electron-microprobe analysis of the same material. The Rietveld refinements…
The pressure-induced Raman shifts for several internal vibrations of poly(methyl methacrylate) (PMMA) and polycarbonate (PC) were studied over the range 0–35 kbar. The 600 cm−1 C–C–O and 813 cm−1 C–O–CH3 symmetric stretches of PMMA were found to have mode Grüneisen parameters of 0.081±0.002 and 0.047±0.001, respective…
Abstract Bronzefarbenes Di(phthalocyaninato(1−))lanthanidpolybromid, [Ln(Pc − ) 2 ]Br y (Ln = La…(Ce, Pm)…Lu; y > 1,5) wird durch Oxydation von ( n Bu 4 N)[Ln(Pc 2− ) 2 ] mit überschüssigem Brom dargestellt. In den UV‐VIS‐NIR‐Spektren treten die für den Pc − ‐Liganden typischen B‐ und Q 1 ‐Absorptionen bei ≈ 14 kK…
Abstract The new compounds ThCu 1-x PO and ThCuAsO with ZrCuSiAs-type structure were prepared in well crystallized form by chemical vapor transport reactions. Th 2 Ni 3-x P 3 O with a new structure type was obtained by reaction of ThO 2 with the other elemental components in an alumina crucible at high temperatures.…