Materials Literature
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Conduction mechanism in ionic glasses is still considered one of the great challenges in physics and chemistry of glasses [A. Bunde, K. Funke, and M. Ingram, Solid State Ionics 105, 1 (1998)]. We show that consequent application of the routine percolation theory leads to the consistent description of most puzzling con…
A lattice Boltzmann model for amphiphilic fluid dynamics is presented. It is a ternary model, in that it conserves mass separately for each chemical species present (water, oil, amphiphile), and it maintains an orientational degree of freedom for the amphiphilic species. Moreover, it models fluid interactions at the m…
Opals are structures composed of the closed packing of spheres in the size range of nano-to-micro meter. They are sintered to create small necks at the points of contact. We have solved the diffusion problem in such structures. The relation between the diffusion coefficient and the termal and electrical conductivity m…
Hall resistivity and magneto-thermopower have been measured for colossal magnetoresistive Tl2Mn2O7 over wide temperature and magnetic-field ranges. These measurements revealed that a small number of free electron-like carriers is responsible for the magneto-transport properties. In contrast to perovskite CMR materials…
We study the dynamics of island nucleation in the presence of adsorbates using kinetic Monte Carlo simulations of a two-species growth model. Adatoms (A-atoms) and impurities (B-atoms) are codeposited, diffuse and aggregate subject to attractive AA- and AB-interactions. Activated exchange of adatoms with impurities is…
In a recent letter, (Phys. Rev. Lett. 82, 2892(1999); cond-mat/9808306) Kamien and Lubensky calculated the energy of the surface constructed via a linear superposition of screw dislocations in SmA phase, and obtained the positive (repulsive) sign of the long-range interaction between dislocations. We would like to obj…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSelf-Assembly of Nanoscopic Dodecahedra from 50 Predesigned ComponentsBogdan Olenyuk, Michael D. Levin, Jeffery A. Whiteford, Jeffrey E. Shield, and Peter J. StangView Author Information Department of Chemistry and Department of Materials Science and Engineering Univer…
A solution of cadmium selenide nanocrystals was used to print inorganic thin-film transistors with field effect mobilities up to 1 square centimeter per volt second. This mobility is an order of magnitude larger than those reported for printed organic transistors. A field effect was achieved by developing a synthesis…
A new family of polyesters, the poly(tetramethylene terephthalate dicarboxylates) of formula [−O−CO−C 6 H 4 −CO−O−(CH 2 ) x −O−CO−(CH 2 ) y −CO−O−(CH 2 ) x ] n, was synthesized and characterized by 1 H and 13 C NMR in CDCl 3 solution, infrared spectroscopy, molecular weight distribution, and X-ray fiber diffraction an…
Cationic sulfenatocobalt(III) complexes, with the remaining ligands amines, are deoxygenated upon reaction with hydrated methyldioxorhenium(V). The reactions of (Am) 5 Co−S(O)R 2+ yield the thiolato complexes (Am) 5 Co−SR 2+ and methyltrioxorhenium(VII), MTO. A kinetic study of these reactions was carried out, using t…
An embedded cluster model is used to estimate the molecular dipole moment of crystalline dimethylnitramine (DMNA). The electrostatic potential due to the crystal is included in the calculation via the SCREEP (surface charge representation of the electrostatic embedding potential) approach. The resulting dipole moment…
The distribution of pores, based on spinodal phase separation in sodium borosilicate glasses that were rapidly quenched at different cooling rates, was investigated. The N 2 adsorption−desorption behavior of samples shows that the pore is of the micropore type with pore size <1 nm. The air-quenched samples (quenched a…
We have investigated the structure of binary lead phosphate glasses using 1D 31 P MAS and 2D 31 P double-quantum NMR. The distribution of the Q n phosphate species, determined from the simulation of 1D MAS spectra, indicates a significant disproportionation reaction (2Q n ↔ Q n +1 + Q n - 1 ) near the pyrophosphate co…
A nonracemic compound is synthesized and shown to assemble reversibly through hydrogen bonding to form a cyclic tetramer. The chiral arrangement of atoms in the individual pieces becomes amplified through self-assembly to yield multiple functional groups asymmetrically arranged within the cavity. The tetrameric capsul…
Oxidation of a graphite initiated from surface defects is investigated by using scanning tunneling microscopy (STM) and density functional (DF) calculation. The defects are created on a graphite surface with controlled depth and density by impact of Ar + ions at low energies (50−500 eV). Oxidation of the defects with…
The synthesis and characterization of divalent [Fe(TC-5,5)] (1) and trivalent [Fe(OTf)(TC-5,5)] (2) tropocoronand complexes are described. Compound 1 reacts with 1 equiv of NO to form the {FeNO} 7 complex 3 . A single-crystal X-ray structure determination of 3 reveals a trigonal bipyramidal geometry with a linearly co…
High proton conducting P 2 O 5 −SiO 2 glasses were prepared using the sol−gel method, the electrical conductivities of which were studied in relation to the pore structure and the adsorbed water. The pore properties of SiO 2 and P 2 O 5 −SiO 2 glasses were controlled by addition of formamide during the gel synthesis,…
The mechanical properties of the double gyroid (DG) cubic phase in glassy−rubbery block copolymer systems are examined. The stress−strain properties of an isoprene-rich polystyrene/polyisoprene/polystyrene (SIS) triblock and a polystyrene/polyisoprene (SI) starblock DG, both comprised of two separate interpenetrating…
Thicker-walled mesoporous MCM-41 silicas with improved thermal and hydrothermal stability were prepared via secondary crystallization (in which calcined MCM-41 was used as silica source) or by using long crystallization times. Unusually, the thicker pore walls of the as-synthesized (surfactant containing) forms of the…
Polyether dendritic compounds bearing folate residues on their surface were prepared as model drug carriers with potential tumor cell specificity. Starting from ester-terminated polyether dendrimers, hydrazide groups were easily introduced to the surface of the dendrimers by reaction with hydrazine. Folate residues we…