Materials Literature
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Recently we have found that carbons can be grown into well-aligned two-dimensional sheets (dubbed carbon nanowalls) on a substrate through manipulating the electrical conduction from the catalyst to the bias electrode in a microwave plasma enhanced chemical vapor deposition system. The existence of a strong lateral el…
The gas-phase derivatization procedure was employed for direct (i.e., without chemical activation of terminal carboxylic groups) amidization of oxidized single-walled carbon nanotubes (SWNTs) with simple aliphatic amines. The procedure includes treatment of SWNTs with amine vapors under reduced pressure and a temperat…
Carbon nanotubes yield to mechanical force by a primary dislocation dipole whose formation energy describes the thermodynamic stability of the tubule. However, the real-time strength is determined by the rate of defect formation, defined in turn by the activation barrier for the bond flip. First extensive computations…
The influence of the charge density of polyelectrolytes on the growth of polyelectrolyte multilayers via layer-by-layer self-assembly from pure aqueous solutions was studied. Multilayers were built from strong polyanions, namely poly(styrenesulfonate) and an exfoliated synthetic hectorite, and cationic copolymers of d…
The atomistic structure and energetics of the Sigma 13 (10-14)[1-210] symmetrical tilt grain boundary in alpha-Al2O3 are studied by first-principles calculations based on the local-density-functional theory with a mixed-basis pseudopotential method. Three configurations, stable with respect to intergranular cleavage,…
Optimally doped silver selenide and silver telluride exhibit linear positive magnetoresistance over decades in magnetic field and on a scale comparable to the colossal magnetoresistance compounds. We use hydrostatic pressure to smoothly alter the band structure of Ag-rich and Ag-deficient samples of semiconducting Ag(…
It is possible to discuss the propagation of an electronic current through certain layered nanostructures modeling them as a collection of random one-dimensional interfaces, through which a coherent signal can be transmitted or reflected while being scattered at each interface. We present a simple model in which a per…
The effective Hamiltonian for perovskite titanates is derived by taking into account the threefold degeneracy of ${t}_{2g}$ orbitals and the strong electron-electron interactions. The magnetic and orbital ordered phases are studied in the mean-field approximation applied to the effective Hamiltonian. A large degenerac…
The ground-state and excited-state properties of the perovskite ${\mathrm{LaMnO}}_{3},$ the mother material of colossal magnetoresistance manganites, are calculated based on the generalized-gradient-corrected relativistic full-potential method. The electronic structure, magnetism, and energetics of various spin config…
Interaction of the lacunary [alpha-XW(9)O(33)](9-) (X = As(III), Sb(III)) with Fe(3+) ions in acidic, aqueous medium leads to the formation of dimeric polyoxoanions, [Fe(4)(H(2)O)(10)(beta-XW(9)O(33))(2)](6-) (X = As(III), Sb(III)) in high yield. X-ray single-crystal analyses were carried out on Na(6)[Fe(4)(H(2)O)(10)…
Fully dense polycrystalline Ti3AlC2 was fabricated by a solid–liquid reaction synthesis and simultaneous in-situ hot pressing of a mixture of Ti, Al and graphite powders at 1500 °C and 25 MPa for 5 minutes and subsequently annealing at 1200 °C for 20 minutes. The effects of various parameters including composition of…
Abstract Polysiloxane ionomers bearing pendant quaternary ammonium groups were synthesized through the Menshutkin reaction of poly(γ‐chloropropylmethylsiloxane‐ co ‐dimethylsiloxane) with N , N ‐dimethylbenzylamine. Ion aggregation in the ionomers with different contents of the quaternary ammonium groups was investiga…
The purpose of this paper is to present basic functional principles of high frequency x-ray generators. The emphasis is put on physical concepts that determine the engineering solutions to the problem of efficient generation and control of high voltage power required to drive the x-ray tube. The physics of magneticall…
Assistive technology, specifically in the area of wheelchair seating, has advanced tremendously in the past decade. Over 200 wheelchair cushion models are commercially available. This increased selection brings greater options to the end user. However, having more options places greater importance on the ability to ma…
The structures of poly(1,4-phenylenesulfone), [1,4-ArSO 2 ] n (Ar = 1,4-phenylene), and its tetrasulfone oligomer ArSO 2 ArSO 2 ArSO 2 ArSO 2 Ar (Ar = phenyl or 1,4-phenylene) have been determined from X-ray powder diffraction data interfaced to molecular simulation and diffraction modeling. An initial model for the t…
A third generation poly(propylene imine) dendrimer functionalized with oligo(phenylene vinylene) groups is used as a stabilizing agent in the fabrication of CdS nanoparticles. The solvent-dependent conformational behavior of this electroactive dendrimer is used to generate various organic−inorganic semiconductor compo…
Cluster-derived bimetallic nanoparticles have been deposited onto multi-wall carbon nanotubes and shown to be generally homogeneously dispersed, of uniform small sizes, of the same composition as the starting mixed-metal clusters, and to have a tendency to align at the tips of the tubules.
$B$-site substitution effects on the structural and magnetic properties are investigated in ${\mathrm{Nd}}_{1/2}{\mathrm{Ca}}_{1/2}$$({\mathrm{Mn}}_{0.97}{M}_{0.03})$${\mathrm{O}}_{3}$ $(M=\mathrm{Al},$ Zn, Sc, Fe, Ni, Co, and Cr). With decreases of temperature below $\ensuremath{\sim}200 \mathrm{K},$ these compounds…
The local structure and electronic state of a photomagnetic material ${\mathrm{Cs}}_{0.8}{\mathrm{Co}}_{1.1}(3\ensuremath{-}\mathrm{cyanopyridine}{)}_{1.9}\mathrm{W}(\mathrm{CN}{)}_{8}\ensuremath{\cdot}2.1{\mathrm{H}}_{2}\mathrm{O}$ have been investigated by means of x-ray-absorption fine structure (XAFS) spectroscopy…
A new rod-like coordination polymer consisting of (Ru-(terpy)2) motifs bridged by bithiophene units has been prepared by electrochemical polymerisation in acidic organic medium.