Materials Literature
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Abstract The long range orientational order of a liquid crystal is one of its prime characteristics. Before the extent of this order can be measured, however, it is necessary to define what is meant by the orientational order. This can be achieved in a variety of ways the most pragmatic of which is via the order param…
High spin ↔ low spin electronic spin crossovers may be observed in a number of transition metal complexes when the ligand-field and electron-pairing energies happen to be comparable in magnitude. They are obtained under the effect of an external perturbation such as a variation of temperature, a variation of pressure…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPorphocyanine: an expanded tetrapyrrolic macrocycleDavid Dolphin, Steven J. Rettig, Hang Tang, Tilak Wijesekera, and Lily Yun XieCite this: J. Am. Chem. Soc. 1993, 115, 20, 9301–9302Publication Date (Print):October 1, 1993Publication History Published online1 May 2002Publish…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMorphology and growth kinetics of large sodium chlorate crystals grown in the presence and absence of sodium dithionate impurityR. Ristic, J. N. Sherwood, and K. WojciechowskiCite this: J. Phys. Chem. 1993, 97, 41, 10774–10782Publication Date (Print):October 1, 1993Publicati…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface enrichment in polystyrene/poly(vinyl methyl ether) blends. 3. An analysis of the near-surface composition profileJ. M. G. Cowie, B. G. Devlin, and I. J. McEwenCite this: Macromolecules 1993, 26, 21, 5628–5632Publication Date (Print):October 1, 1993Publication History…
A hybrid spectral/FDTD (finite-difference-time-domain) method is introduced for the analysis of electromagnetic wave propagation in anisotropic, inhomogeneous, periodic structures. Discrete Fourier series representations for the field components are used for the spectral calculation of spatial derivatives along the ax…
Abstract In this study, styrene‐(ethylene‐co‐butylene)‐styrene (SEBS) triblock copolymer (Kraton G‐1652) was modified with maleic anhydride (MA). The maleated SEBS was used as compatibilizer for the blends of Nylon 6 (PA6) and SEBS. The morphology and impact strength of the blends were measured as functions of concent…
The structure of zeolite ZSM-23 (structure-type code MTT) loaded with NH4F [ao = 11.129 (1), bo = 5.025 (1) and Co = 21.519 (1) Å and β = 89.85 (4)°] was refined from high-resolution synchrotron X-ray powder data. The Rietveld refinement converged in space group P1211 (No. 4) to RF = 0.090 and Rwp = 0.085, confirming…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOptically active allylsilanes. 17. Preparation of silafunctional allylsilanes by palladium-catalyzed silylation of allylic chlorides with 1,1-dichloro-1-phenyl-2,2,2-trimethyldisilaneYonetatsu Matsumoto, Akira Ohno, and Tamio HayashiCite this: Organometallics 1993, 12, 10, 4…
The properties of the compounds of the family Per2M(mnt)2 with α phases are reviewed taking into account recent experimental results. The perylene chains, responsible for electronic conduction undergo Peierls transitions at low temperatures. In the cases of M= Pt, Pd and Ni, the chains of M(mnt)2 − units with localise…
In order to investigate the relationships between the three-dimensional structure and the enzymic activity of E. coli RNase HI, three mutant proteins, which were completely inactivated by the replacements of three functional residues, Asp10 by Asn (D10N), Glu48 by Gln (E48Q), and Asp70 by Asn (D70N), were crystallized…
Abstract The crystallisation behaviour on cooling of concentrated solutions of polyacrylonitrile (PAN) in two organic solvents, gamma butyrolactone (gBL) and ethylene carbonate (EC), was investigated. gBL is a liquid but EC is a crystalline solid at 20°C. Wide angle X‐ray diffraction studies showed that the peaks from…
Three new series with a tolane core and a chiral L-lactic acid moiety have been synthesized. The theoretically predicted SA-TGBA-N∗ phase sequence is found in several compounds with short chains. The smectic A twist grain boundary phase (TGBA) obtained with a cholesteric texture, is characterized by different techniqu…
Perturbed-angular-correlation measurements were carried out after implantation of $^{111}\mathrm{In}$ into amorphous and polycrystalline powder samples of \ensuremath{\alpha}- and \ensuremath{\beta}-${\mathrm{Ga}}_{2}$${\mathrm{O}}_{3}$, and single crystals of \ensuremath{\beta}-${\mathrm{Ga}}_{2}$${\mathrm{O}}_{3}$.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new synthetic approach to poly- and perfluorinated polyethersMing H. Hung, William B. Farnham, Andrew E. Feiring, and Shlomo RozenCite this: J. Am. Chem. Soc. 1993, 115, 20, 8954–8959Publication Date (Print):October 1, 1993Publication History Published online1 May 2002Publ…
Polymeric fibers were produced from a polyaluminocarbosilane obtained by reacting polycarbosilane and an aluminum alkoxide modified with a β‐ceto ester. The pre‐ceramic fibers were converted into amorphous Si‐Al‐O‐N ceramic fibers after a pyrolysis process under flowing ammonia at 1000°C. 29 Si and 27 Al magic‐angle s…
For 65 years it has been discussed whether hexatungstate ions exist. Now the confirmation of their existence and the structural analysis of Na5[H3W6O22] · 18H2O have been achieved; in aqueous solution the latter is probably in equilibrium with the known [W7O24]6− ion. The polyhedral representa tion of the structure of…
The X-band electron paramagnetic resonance study of Er-doped Bi4Ge3O12 single crystals at 5 K is reported. The spectra have been attributed to Er3+ ions in the Bi3+ site, confirming the assumed trigonal site symmetry of Er3+ in previous crystal-field analysis. A detailed study of the measured g-factor values indicates…
Preliminary results of ongoing crack growth studies being performed on an API X-65 line pipe steel in a low-pH cracking environment were reported. Objectives were to reproduce low-pH crack propagation in the laboratory, to identify a crack driving force parameter, and to evaluate the influence of environmental and mec…
RATIONALE AND OBJECTIVES: The purpose of this study was to further develop and compare manganese-based liposomes prepared by two different approaches wherein a manganese ion was entrapped within the internal aqueous space of the vesicles or into the bilayer surface via membrane bound complexes. METHODS: Small unilamel…