Materials Literature
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The synthesis of CdS and CdSe nanocrystallites using the thermolysis of several dithio- or diselenocarbamato complexes of cadmium in trioctylphosphine oxide (TOPO) is reported. The nanodispersed materials obtained show quantum size effects in their optical spectra and exhibit near band-edge luminescence. The influence…
The ability of organisms to exercise control over crystal growth is wonderfully exemplified by skeleton formation in echinoderms. A sea urchin spine is a unique composite of a single crystal of calcite and glycoproteins intercalated inside the crystal during its growth. Here we performed a detailed morphological and h…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTMonoglyceride Synthesis by Heterogeneous Catalysis Using MCM-41 Type Silicas Functionalized with Amino GroupsAnne Cauvel, Gilbert Renard, and Daniel BrunelView Author Information Laboratoire de Matériaux Catalytiques et Catalyse en Chimie Organique, UMR 5618 CNRS-ENSCM and CPI…
The oxidation of hydrogen-terminated porous silicon surfaces produced by electrochemical etching has been studied using transmission FTIR spectroscopy. The surface is passivated to oxidation by surface hydrogen below about 523 K. Above this temperature as hydrogen depletion occurs by H 2 evolution, Si surface dangling…
Microstructural observations of damage around indentations in Ti 3 SiC 2 are presented. The Vickers hardness decreased with increasing load and asymptotically approached 4 GPa at the highest loads. No indentation cracks were observed even at loads as high as 300 N. Preliminary strength versus indentation plots indicat…
A molecular triad consisting of a diarylporphyrin (P) covalently linked to a carotenoid polyene (C) and a fullerene (C 60 ) has been prepared and studied using time-resolved spectroscopic methods. In 2-methyltetrahydrofuran solution, the triad undergoes photoinduced electron transfer to yield C−P •+ −C 60 •-, which ev…
Abstract Biofibers, natural lignocellulosics, have an outstanding potential as a reinforcement in thermoplastics. This study deals with the preparation of lignocellulosic composites by reactive extrusion processing in which good interfacial adhesion is generated by a combination of fiber modification and matrix modifi…
The rational design, the synthesis via a new convergent approach, and the characterization of four generations of monodendrons based on the AB 3 building block methyl 3,4,5-trishydroxybenzoate are described. The first generation monodendrons are crystalline. The second generation methyl 3,4,5-tris-3‘,4‘,5‘-[tris( n -d…
An attempt was made to prepare porous carbon by using the channels of Y zeolite as a template. Poly(acrylonitrile) and poly(furfuryl alcohol) were carbonized in the zeolite channels and the resultant carbon/zeolite complexes were subjected to acid treatment in order to extract carbon from the zeolite framework. In add…
Abstract Topological considerations concerning the ratio of linear, imperfectly branched, dendritic and terminal units in hyperbranched polymers based on AB 2 , AB 3 and AB m (m≥2) type monomers are summarized. The reaction of AB 2 monomers with a core molecule of the structure B f is also treated. For larger hyperbra…
The electrochemical and optical properties of lithium phosphorous oxynitride (Lipon) thin films have been studied with an emphasis on the stability window vs. lithium metal and the behavior of the Li/Lipon interface. Impedance measurements made between −26 and 140°C show that Lipon exhibits a single, Li + ‐ion conduct…
The thermal effect of a reaction makes the temperature inside the reaction system deviate from a prescribed heating program. To take into account the effect of such temperature deviations on kinetic evaluations, a computational method applicable to an arbitrary variation in temperature has been developed. The method c…
Magnetic coupling constants (2 J ) of hydroxo- and alkoxo-bridged copper binuclear compounds have been evaluated to determine the accuracy of different density functional methods and to study the magnetic behavior of these compounds. Comparison between the calculated and experimental coupling constants for the complet…
The unusual magnetic properties of ${\mathrm{La}}_{0.5}$ ${\mathrm{Ca}}_{0.5}$ ${\mathrm{MnO}}_{3}$ were found to be associated with structural and magnetic ordering phenomena, resulting from the close interplay between charge, orbital, and magnetic ordering. Analysis of synchrotron x-ray and neutron powder diffractio…
The 23 Glazer tilt systems describing octahedral tilting in perovskites have been investigated. It is shown that in tilt systems a + a + a − , a + b + b − , a + a + c − , a + b + c − , a 0 b + b − and a 0 b + c − it is not possible to link together a three-dimensional network of perfectly rigid octahedra. In these til…
Abstract We discuss the use of regression diagnostics combined with nonlinear least-squares to refine cell parameters from powder diffraction data, presenting a method which minimizes residuals in the experimentally-determined quantity (usually 2θ hkl or energy, E hkl ). Regression diagnostics, particularly deletion d…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemically Active Polymers for Rechargeable BatteriesPetr Novák, Klaus Müller, K. S. V. Santhanam, and Otto HaasView Author Information Paul Scherrer Institute, Electrochemistry Section, CH-5232 Villigen PSI, Switzerland Battelle Institute, CH-1227 Carouge/GE, Switzer…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthetic Principles for Bandgap Control in Linear π-Conjugated SystemsJean RoncaliView Author Information Ingénierie Moléculaire et Matériaux Organiques, CNRS UMR 6501, Université d'Angers, 49045 Angers, France Cite this: Chem. Rev. 1997, 97, 1, 173–206Publication Date (Web…
Data on the physical properties of diamond as a solid state electronics material are briefly discussed with particular emphasis placed on synthetic crystals and plasma-precipitated films.
Pellets of poly(ethylene terephthalate) (PET; 0.48–1.92 g) were heated in anhydrous ethylene glycol (EG; 5 mL) with 2-equivs of NaOH at 150°C for 80 min or 180°C for 15 min to convert them quantitatively to disodium terephthalate (Na2-TPA) and EG. The disodium salt was precipitated quantitatively in pure state from th…