Materials Literature
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Novel layered silica−organic nanostructured materials were prepared by hydrolysis and condensation of alkoxytrichlorosilanes ( n -C n H 2 n +1 OSiCl 3, n = 12, 14, 16, 18, and 20) as single precursors. The formation relies on the self-assembly of alkoxysilanetriols ( n -C n H 2 n +1 OSi(OH) 3 ) generated by the prefer…
Abstract Two aromatic, pyridine‐based ether diamines were prepared by the nucleophilic aromatic substitution reaction of 4‐aminophenol and 5‐amino‐1‐naphthol with 2,6‐dichloropyridine in N ‐methyl‐2‐pyrrolidone as a solvent. Polycondensation reactions of the obtained diamines with pyromellitic dianhydride, benzophenon…
Electronic structure calculations were performed for MnN and ${\mathrm{Mn}}_{3}{\mathrm{N}}_{2}$ using a full-potential linearized muffin-tin orbital method in the local spin density approximation. Structural relaxation by energy minimization and calculations for various different magnetic configurations were performe…
Abstract The orientation of platelets in micro‐meter‐thick polymer‐clay nanocomposite films was investigated with small‐angle neutron scattering (SANS), small‐angle X‐ray scattering (SAXS), and wide‐angle X‐ray diffraction (WAXD). The films with various clay contents (15–60% by mass fraction) were prepared by a layer‐…
Abstract A generalized model for scattering from a collection of independent (isolated) stacks of layers enabled predictions of and parameterized fits to small‐angle X‐ray scattering from layered silicate dispersions. From this fundamental development, example investigations that use small‐angle scattering to examine…
The main feature of an exchange spring magnet can be characterized by ferromagnetic exchange coupling between a magnetically soft phase and a magnetically hard phase. The coupling constant J, a measure of the coupling strength between the two phases, is a key parameter in controlling the spring magnet properties. A fe…
Abstract The amphiphilic block copolymer poly(isoprene‐ block ‐ethylene oxide) was used as a structure‐directing agent for a polysilazane preceramic polymer commercially known as Ceraset. Two block copolymers of different molecular weights and poly(ethylene oxide) weight fractions with body‐centered cubic sphere and h…
Abstract The impact of preconditioning constituent materials on the morphology development of organically modified montmorillonite–epoxy nanocomposites is examined to determine the sensitivity of exfoliation to material conditions. In situ synchrotron small‐angle X‐ray scattering studies were performed to relate the i…
A continuum model for frictional slip of the yarns of a plain-weave fabric is presented. The model is based on the assumption that the weave is composed of two families of continuously distributed yarns constrained at all times to occupy a common evolving surface in three-dimensional space. The two families may slide…
Abstract We employ atomistic computer modeling to investigate the structure and morphology of poly(ethylene oxide) (PEO) chains confined in 1‐nm slit pores defined by montmorillonite silicate layers. Molecular dynamics computer simulations reveal the Li + cations to be located in the immediate vicinity of the silicate…
Optical absorption and electron paramagnetic resonance (EPR) techniques have been used to characterize the production and thermal decay of point defects in undoped single crystals of KD2PO4 grown at Lawrence Livermore National Laboratory. A crystal was irradiated at 77 K with x rays, and then warmed to room temperatur…
${\mathrm{ZnNMn}}_{3}$ has an unusual cubic-to-cubic structural phase transition near 160 K, which coincides with the onset of the antiferromagnetic (AFM) ordering. The phase transformation involves the formation of microcracks induced by the magnetic moment-dependent lattice expansion, which is also accompanied by an…
The first-principles calculation within density-functional theory is used to search for new candidates of half-metallic ferromagnets in semi-Heusler alloys NiCrM (M = P, As, Sb, S, Se and Te). Our calculations predict that NiCrP, NiCrSe and NiCrTe are half-metallic ferromagnets (HMFs) with magnetic moments of nearly 3…
Controlling the spatial organization of cells is a critical step toward engineering tissues with distributed networks of blood vessels or nerve cells. Here we report a new soft-lithography-based approach for micropatterning proteins and cells on the surface of biodegradable chitosan substrates that are more applicable…
A nanoscale gold thin film and its influence on Ti/SnO 2 -Sb 2 O 5 coating have been investigated by scanning electron microscopy (SEM) and electrochemical methods such as cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and the chronopotentiometric technique in both acidic and caustic solutions. The…
Structures and acid−base properties of La/Al 2 O 3 with different La loadings and calcination temperatures were examined by surface-area measurements, catalyses, IR, XRD, and La K-edge XAFS spectroscopic techniques. Novel concepts for sintering mechanism of γ-Al 2 O 3 and the role of La addition to enhance the thermal…
Abstract Monoalkyl‐ and dialkyl‐imidazolium surfactants were used to prepare organically modified montmorillonites with markedly improved thermal stability in comparison with their alkyl‐ammonium equivalents (the decomposition temperatures increased by ca. 100 °C). Such an increase in the thermal stability affords the…
We calculate the parallel (VV) and (VH) perpendicular polarized Raman spectra of amorphous silica. Model ${\mathrm{SiO}}_{2}$ glasses, uncompressed and compressed, were generated by a combination of classical and ab initio molecular-dynamics simulations and their dynamical matrices were computed within the framework o…
Abstract Poly(ethylene terephthalate) (PET)/montmorillonite (MMT) nanocomposites were prepared by solution intercalation method. The clay was organo‐modified with the intercalation agent cetylpyridinium chloride (CPC). Wide‐angle X‐ray diffraction (XRD) showed that the layers of MMT were intercalated by CPC. Four nano…
We measured the high-temperature thermoelectric properties of single-crystal Ca3Co2O6, which consists of parallel one-dimensional Co2O66− chains separated by Ca2+ ions. The resistivity (ρ) along the c-axis decreases rapidly upon increasing temperature from 2×104 to 8 mΩ cm in a temperature region of 300 to 1073 K. The…