Materials Literature
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Pt nanowires are synthesized in organic−inorganic mesoporous silica HMM-1 (channel diameter 3 nm) by photoreduction, and the formation mechanism and isolation of the wires have been studied. UV-irradiation of HMM-1 impregnated with H 2 PtCl 6 for 48 h in the presence of adsorbed water and methanol leads to the formati…
Shear-induced coalescence was studied in immiscible blends of polydimethylsiloxane ~PDMS! and polyisoprene ~PI! with a droplet-matrix morphology, using both rheology and scanning electron microscopy. Dynamic moduli of the blends compatibilized with different amounts of a PDMS–PI diblock were measured. The experimental…
Textured bulk ceramics have been prepared of various cobaltites including the common CdI2-type CoO2 layer (i.e., [Ca2(Co0.65Cu0.35)2O4]0.624[CoO2]: CCO-4-layer, [Bi2M2−xO4]p[CoO2] (M2 = Sr2: BSCO, M2 = Ca1Sr1: B(SC)CO, M2 = Ca2: BCCO)) by using β-Co(OH)2 (CdI2-type) platelets as reactive templates, and their thermoele…
In this paper, the formation of different complex morphologies of nanocrystalline CaCO3 under the control of double hydrophilic block copolymers (DHBCs) carrying phosphate groups is described. The DHBCs consist of a poly(ethylene glycol) (PEG) block and a pendant poly[2-(2-hydroxy ethyl)ethylene] block with different…
Several recent studies demonstrated highly selective ion transport through multilayer polyelectrolyte membranes. This paper examines the transport of neutral molecules through multilayer polyelectrolyte films and shows significant size-based discrimination among organic analytes. Simple 7-bilayer poly(styrene sulfonat…
Thickness dependence and strain effects in films of ${\mathrm{La}}_{1\ensuremath{-}x}{A}_{x}{\mathrm{MnO}}_{3}$ perovskites are analyzed in the colossal magnetoresistance regime. The calculations are based on a generalization of a variational approach previously proposed for the study of manganite bulk. It is found th…
We use energetic considerations to deduce the form of a previously uncertain coupling term in the shear-transformation-zone (STZ) theory of plastic deformation in amorphous solids. As in the earlier versions of the STZ theory, the onset of steady deformation at a yield stress appears here as an exchange of dynamic sta…
Ultrawide ZnO nanosheets together with their formation mechanism have been reported. As the width and thickness of the sheets are in the range of 50–100 µm and 50–100 nm respectively, the width-to-thickness ratios of the sheets reach up to one thousand.
We present results for the elastic properties of a single lamella of montmorillonite consisting of two tetrahedral layers and the intervening octahedral layer. The calculations were performed using a force field with both bonded and nonbonded interatomic contributions and periodic boundary conditions in two dimensions…
The electronic and structural properties of pure and defective cerium oxide are investigated using a unified LDA+U approach which allows to treat the different valence states of Ce occurring for different stoichiometries on a same ground, without any {\it a priori} assumptions on the defect chemistry. The method corre…
In this paper, we review some recent work on amorphous materials using current "first principles" electronic structure/molecular dynamics techniques. The main theme of the paper is to emphasize new directions in the use of such ab initio methods. Some of these, being quite new, need development, but we believe have pr…
The operation of a novel nonvolatile memory device based on a conductive ferroelectric/non-ferroelectric thin film multilayer stack is simulated numerically. The simulation involves the self-consistent steady state solution of Poisson's equation and the transport equation for electrons assuming a Drift-Diffusion trans…
We present Cahn-Hilliard and Allen-Cahn numerical integration algorithms that are unconditionally stable and so provide significantly faster accuracy-controlled simulation. Our stability analysis is based on Eyre's theorem and unconditional von Neumann stability analysis, both of which we present. Numerical tests conf…
In recent years, the paradigm of soft glassy matter has been used to describe diverse nonergodic materials exhibiting strong local disorder and slow mesoscopic rearrangement. As so far formulated, however, the resulting soft glassy rheology (SGR) model treats the shear stress in isolation, effectively scalarizing the…
Single-layer h -BN films may be grown on Ni(111) by using B-trichloroborazine (ClBNH) 3 . Scanning tunneling microscopy shows perfect monolayers with a very low density of defects. This way of producing stoichiometric, ultimately thin h -BN layers is an alternate route to the use of borazine (HBNH) 3 . The h -BN growt…
Using solution spinning, which involves an intermediate gel-state, we obtained exceptionally strong carbon nanotube fibers that are tougher than either spider silk or any fiber used for mechanical reinforcement. We use these fibers to make 100 micron diameter supercapacitors and electronic textiles. Per weight, the en…
A well-ordered hexagonal structure of the mesopores was produced by previous hydrolysis of tetraethoxysilane with hydrochloric acid and subsequent assembly of cationic surfactant micelles and anionic silicate species at a basic condition. Mesoporous silica nanoparticles (20-50 nm) having a well-ordered hexagonal mesos…
Ferritin and bovine serum albumin (BSA) proteins are chemically bonded to nitrogen-doped multi-walled carbon nanotubes (CNx MWNTs) through a two-step process of diimide-activated amidation. First, carboxylated CNx MWNTs were activated by N-ethyl-N′-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDAC), forming a st…
Seeding and autocatalytic reduction of platinum salts in aqueous surfactant solution using ascorbic acid as the reductant leads to remarkable dendritic metal nanostructures. In micellar surfactant solutions, spherical dendritic metal nanostructures are obtained, and the smallest of these nanodendrites resemble assembl…
CO oxidation on TiO2 supported Au has been studied using density functional theory calculations. Important catalytic roles of the oxide have been identified: (i) CO oxidation occurs at the interface between Au and the oxide with a very small barrier; and (ii) O2 adsorption at the interface is the key step in the react…