Materials Literature
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Abstract A new high molecular weight aromatic polyimide has been synthesized from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) and 2,2′‐dimethyl‐4,4′‐diaminobiphenyl (DMB) in p ‐chlorophenol at elevated temperature. BPDA‐DMB fibers have been spun by a dry‐jet wet spinning method. The fibers were elongated and…
Abstract Infrared spectroscopy is used to distinguish between octahedral and tetrahedral substitutions in an interstratified illite-smectite clay. The Hofmann-Klemen (Li) test suggests that the AlMg□ and FeMg□ octahedral vacancies are preferentially occupied by Li after thermal treatment at 250°C. The ammonium (Choura…
Abstract Long‐term compositional changes were observed when n ‐hexane plasma polymers were stored in air at ambient temperature. These post‐deposition changes were monitored over periods exceeding one year using XPS, grazing angle FTIR, and SEM. A rapid initial increase in the oxygen content was followed by a slower o…
While Bragg diffraction data can only reveal average one-body information, such as atomic positions, thermal ellipsoids and site occupancies, diffuse scattering contains two-body information and is thus potentially a rich source of information on how atoms and molecules interact. The two major mathematical approaches…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIonoelectronics. Cation-Induced Nonlinear Complexation: Crown Ether- and Poly(ethylene oxide)-Substituted Lutetium BisphthalocyaninesThierry Toupance, Vefa Ahsen, and Jacques SimonCite this: J. Am. Chem. Soc. 1994, 116, 12, 5352–5361Publication Date (Print):June 1, 1994Publi…
Abstract X-ray absorption spectroscopy (XAS) was used to determine the local molecular environment of Co(II) surface complexes sorbed on three different kaolinites at ambient temperature and pressure in contact with an aqueous solution. Interatomic distances and types and numbers of backscattering atoms have been deri…
Prolonged exposure to vincristine correlates with improved therapeutic activity. In this work, two methods are used to increase the circulation longevity of liposomal formulations of vincristine. The first involves incorporation of the ganglioside GM1, which acts to increase the circulation longevity of liposomal carr…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTComparative Study of the Synthesis and Properties of Vanadate-Exchanged Layered Double HydroxidesMaria-Angeles Ulibarri, Francisco M. Labajos, Vicente Rives, Raquel Trujillano, Winnie Kagunya, and William JonesCite this: Inorg. Chem. 1994, 33, 12, 2592–2599Publication Date (…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of Several Isomeric Tetrathiafulvalene .pi.-Electron Donors with Peripheral Sulfur Atoms. A Study of Their Radical CationsConcepcio Rovira, Jaume Veciana, Nuria Santalo, Judit Tarres, Joan Cirujeda, Elies Molins, Jordi Llorca, and Enrique EspinosaCite this: J. Org.…
The structural and optical properties of RF magnetron sputtered ITO films without in situ substrate heating and post-deposition annealing are investigated. The structure and orientation of ITO films strongly depends on the energy of the sputtered particles arriving at the substrate. As the sputtering power increases f…
Abstract Fourier‐transform infrared spectral studies of an amorphous linear aromatic polyurethane at various temperatures were performed. Hydrogen bonding was studied in the NH stretching (3347 cm −1 ) and the bending (1535 cm −1 ) regions, using the band decomposition technique. The variations with temperature are u…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of Free Polymer on the Structure of a Polymer Brush and Interaction between Two Polymer BrushesC. M. Wijmans, E. B. Zhulina, and G. J. FleerCite this: Macromolecules 1994, 27, 12, 3238–3248Publication Date (Print):June 1, 1994Publication History Published online1 May…
Dense Sic ceramics were obtained by pressureless sintering of β‐Sic and α‐Sic powders as starting materials using Al 2 O 3 ‐Y 2 O 3 additives. The resulting microstructure depended highly on the polytypes of the starting SiC powders. The microstructure of SiC obtained from α‐SiC powder was composed of equiaxed grains,…
We present a spectroscopic overview of ${\mathrm{Cr}}^{4+}$-doped ${\mathrm{Y}}_{3}$${\mathrm{Al}}_{5}$${\mathrm{O}}_{12}$ (YAG), a new laser material for the near-infrared region (NIR). It is found that only 2% of the Cr ions are tetrahedrally coordinated ${\mathrm{Cr}}^{4+}$. However, the optical spectra are dominat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIn situ x-ray diffraction study of crystallization kinetics in PbZr1-xTixO3, (PZT, x = 0.0, 0.55, 1.0)Angus P. Wilkinson, James S. Speck, Anthony K. Cheetham, Srinivasan Natarajan, and John Meurig ThomasCite this: Chem. Mater. 1994, 6, 6, 750–754Publication Date (Print):June…
Two different kinds of europium(III) chelates, luminescent and nonluminescent, were prepared. The chelates were coupled to bioanalytical reagents, such as antibodies, after activations of the amino group on the chelates with thiophosgene,2,4,6-trichloro-1,3,5-triazine, or iodoacetic anhydride. The reactivities of the…
Abstract Poly(vinylidene difluoride) (PVDF) films were irradiated by means of heavy ions (in the electronic stopping‐power range) and electrons. Both types of ionizing radiation induce in the polymer film ionizations and excitations, but swift heavy ions induce a huge density of excitations and ionizations along the i…
A methodology for the straightforward and consistent evaluation of the constituent properties of ceramic‐matrix composites (CMCs) is summarized, based on analyses from the literature. The results provide a constitutive law capable of simulating the stresshain behavior of these materials. The approach is illustrated us…
A thermodynamically stable face-centred icosahedral phase with a pentagonal dodecahedral solidification morphology has been found in Zn[sbnd]Mg[sbnd]RE (RE [tbnd] Y, Tb, Dy, Ho or Er) alloys. We report here the structure, stability and morphology in this new group of icosahedral alloys on the basis of results for the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural Characterization of Sol-Gel Derived Oxycarbide Glasses. 1. Study of the Pyrolysis ProcessLaurence Bois, Jocelyne Maquet, Florence Babonneau, Hubert Mutin, and Djamilha BahloulCite this: Chem. Mater. 1994, 6, 6, 796–802Publication Date (Print):June 1, 1994Publicati…