Materials Literature
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Spectroscopic and magnetic studies on α-Li 3 Fe 2 (PO 4 ) 3 show an interesting behavior below the transition temperature (29 K). The compound orders antiferromagnetically, presenting a weak ferromagnetic moment, which diminishes with temperature. In the same region of temperatures, the Mössbauer spectra split in two…
Siloxane-anchored monolayer films are best prepared by the self-assembly of trichlorosilanes. The moisture sensitivity and chemical reactivity of the trichlorosilane moiety complicates the synthesis and purification of the ω-functionalized alkyltrichlorosilanes that are the building blocks for functionalized monolayer…
For developing clinically useful porphyrin drugs, it is essential to characterize porphyrin−membrane interactions and to determine the factors that modulate such interactions. To this end, four uniquely p -phenyl-substituted tetraphenylporphyrins were synthesized. These water-insoluble, unsymmetrically substituted por…
A series of block polymers were synthesized from tetrahydropyranyl methacrylate (THPMA) and several fluorinated methacrylates. By changing both the length of the fluorinated side chain and the nature of its end group, the surface properties of these polymers were greatly influenced. The polymers with perfluoroheptyl g…
The bonding of triethylphosphine oxide (TEPO) to the acid site of a surface produces a systematic change in the phosphorus-31 isotropic chemical shift that is proportional to the acid strength of the adsorption site. The acidity of several amorphous solid acids of various strengths, several zeolites (HZSM-5, HY, TS-1,…
Ca 2 FeMoO 6 perovskite has been prepared in polycrystalline form by controlled reduction of previously decomposed citrate precursors. This material has been studied by X-ray and neutron powder diffraction (NPD), scanning electron microscopy, thermal analysis, and magnetic and magnetotransport measurements. The crysta…
The fabrication of boron nitride nanotubules and BN-based composite nanostructures within the pores of anodic aluminum oxide is described. Boron nitride nanotubules are produced by pyrolyzing 2,4,6-trichloroborazine over alumina templates at 750 °C. The nanotubules are polycrystalline, with crystallites exhibiting an…
Argon adsorption isotherms were measured at 87 K for two macroporous silicas and a series of high-quality MCM-41 silicas with approximately cylindrical pores of average diameters from 2 to 6.5 nm. The pore sizes of the MCM-41 samples were accurately determined in earlier studies on the basis of powder X-ray diffractio…
We present an unambiguous formulation for the total energy density within density-functional theory. We propose that it be used as a tool for the interpretation of computed energy and electronic structure changes during structural transformations and chemical reactions, augmenting the present use of electron density c…
The solubility of rare earths at a level of 0.5 mol% in traditional heavy metal oxide glasses based on bismuth, lead and gallium is limited to the largest cations Pr, Nd and Sm. Within the families of these oxide glasses, a higher level of doping was achieved in this work with a heavy metal oxide glass containing germ…
We describe a color separation optical element with potential display applications that is designed to separate light into an array of red, green, and blue stripes formed at a certain distance from the component. The stripe color separation grating is a surface-relief diffractive optical element composed of a repeated…
A series of 9-phenylcarbazole ethynylene monodenrons have been prepared by palladium-catalyzed coupling reactions creating well-organized arrays of redox centers. The tert-butyl groups attached to the 3,6-positions of peripheral 9-phenylcarbazole monomers provide adequate solubility to a limited degree. Trimer and 7-m…
The behavior of spin diffusion in doped semiconductors is shown to be qualitatively different than in undoped (intrinsic) ones. Whereas a spin packet in an intrinsic semiconductor must be a multiple-band disturbance, involving inhomogeneous distributions of both electrons and holes, in a doped semiconductor a single-b…
The essential features of a full potential electronic structure method using Linear Muffin-Tin Orbitals (LMTOs) are presented. The electron density and potential in the this method are represented with no inherent geometrical approximation. This method allows the calculation of total energies and forces with arbitrary…
We have calculated the adsorption energy of carbon monoxide on a monolayer of copper adsorbed on the (111) face of cubic zirconia. We investigate the structural parameters of three phases of bulk zirconia (cubic, tetragonal, and monoclinic) and find excellent agreement with experiment. We have also analyzed the struct…
The wetting of solid surfaces by fluids is a problem of great practical importance that has been extensively studied over the years. Most often, the experimental work has involved measurements of the contact angle made by a liquid on the solid surface of interest. Young's equation gives the relation between the contac…
Two kinds of configurations involving steps on surfaces are reviewed. The first one results from an initially planar vicinal surface, i.e. slightly deviating from a high-symmetry (001) or (111) orientation. In some cases, these surfaces separate into domains of different orientations by a mechanism which is very simil…
The most popular electronic structure method, the linear muffin-tin orbital method (LMTO), in its full-potential (FP) and relativistic forms has been extended to calculate the spectroscopic properties of materials form first principles, i.e, optical spectra, x-ray magnetic circular dichroism (XMCD) and magneto-optical…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTThe Synthesis of Hybrid Polymers Using Atom Transfer Radical Polymerization: Homopolymers and Block Copolymers from Polyhedral Oligomeric Silsesquioxane MonomersJeffrey Pyun and Krzysztof MatyjaszewskiView Author Information Center for Macromolecular Engineering, Department of…
The orientation of surface-active molecules at interfaces is extremely important in determining the dynamic and equilibrium properties of such systems. Films of fatty acid salts were studied at various pH values of the solutions. It was found that there exists a pH where minimum evaporation of water, maximum foamabili…