Materials Literature
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$\mathrm{O}\phantom{\rule{0.3em}{0ex}}1s$ absorption spectroscopy (XAS) and $\mathrm{O}\phantom{\rule{0.3em}{0ex}}K\ensuremath{\alpha}$ emission spectroscopy (XES) were performed to study the electronic structure of nanostructured ZnO. The band gap is determined by the combined absorption-emission spectrum. Resonantly…
Enhanced field emission from ZnO nanowires grown on carbon cloth (see Figure) has been measured. These emitters produced a field emission current density of 1 mA cm–2 at about 0.7 V μm–1, corresponding to an exceptionally high field-enhancement factor of 4.11 × 104. Such an extremely high field-enhancement factor is b…
The high dielectric constant in “SrCu3Ti4O12” and the giant dielectric constant in CaCu3Ti4O12 are based on a barrier layer mechanism. Conductivity in the conducting regions is related to Ti on Cu sites. The insulating barriers are between crystallites in “SrCu3Ti4O12” but within the crystallites in CaCu3Ti4O12.
Porous carbons with mesoporous walls (see Figure) are produced by template replication of aggregates of small silica particles, which were themselves templated by a self-assembled lattice of larger monodisperse polystyrene spheres. A direct methanol fuel cell using the new material as a catalyst support shows signific…
Swelling (and shrinking) of poly(2-vinylpyridine), P2VP, polymer brushes, caused by pH changes, could be readily monitored by transmission surface plasmon resonance, T-SPR, spectroscopy. Gold nanoparticles attached to the P2VP polymer brushes dramatically enhanced the pH-induced shift in the T-SPR absorption spectra.…
The observation of the regulation of fast protein dynamics in a cellular context requires the development of reliable technologies. Here, a signal regulation cascade reliant on the stimulus-dependent acceleration of the bidirectional flow of mitogen-activated protein kinase (extracellular signal-regulated kinase) acro…
Negative refraction is currently achieved by driving the magnetic permeability and electrical permittivity simultaneously negative, thus requiring two separate resonances in the refracting material. The introduction of a single chiral resonance leads to negative refraction of one polarization, resulting in improved an…
An array of single nonmagnetic metallic split rings can be used to implement a magnetic resonance, which arises from an inductor-capacitor circuit (LC) resonance, at 100-terahertz frequency. The excitation of the LC resonance in the normal-incidence geometry used in our experiments occurs through the coupling of the e…
By introducing twist during spinning of multiwalled carbon nanotubes from nanotube forests to make multi-ply, torque-stabilized yarns, we achieve yarn strengths greater than 460 megapascals. These yarns deform hysteretically over large strain ranges, reversibly providing up to 48% energy damping, and are nearly as tou…
We demonstrate the efficient chemical vapor deposition synthesis of single-walled carbon nanotubes where the activity and lifetime of the catalysts are enhanced by water. Water-stimulated enhanced catalytic activity results in massive growth of superdense and vertically aligned nanotube forests with heights up to 2.5…
In this paper, the basic features of the novel field of the use of phase diagrams for the description of metastability will be outlined.Examples of experimental determination and calculation of metastable phase diagrams will be presented.In particular, metastable phase diagrams will be used to describe phase selection…
Using simulations and theoretical arguments we investigate the specular reflection of a perforated gold film deposited on a glass substrate. A square lattice of cylindrical holes is assumed to produce the periodic lateral corrugation needed to hybridize the surface plasmons with radiative states. It is shown that, con…
Abstract Elastic continuum model is used to model acoustic phonons in single wall nanotubes (SWNTs). Based on elastic continuum theory, acoustic vibrational modes are modeled for both zigzag and armchair nanotubes of finite length using a variational solution of Donnell's equation. The acoustic phonon modes in these c…
The role of residual stress in enhancing the fracture properties of the shell Ensis siliqua (razor shell) is reported. Using energy-variable synchrotron X-ray diffraction it is shown that the calcium carbonate crystals are preferentially orientated as a function of depth. Using scanning electron microscopy the structu…
The mass attenuation coefficients for Y 2 O 3 , BaCO 3 , CuO compounds, and solid-state forms of YBa 2 Cu 3 O 7 superconductor were determined at energies of 57.5, 59.5, 65.2, 74.8, 77.1, 87.3, 94.6, 98.4, 122, and 136 keV. The samples were irradiated using a 241 Am point source emitting 59.5 keV photon energies and a…
By a magnetic-field-inducing technique, $\mathrm{Bi}\text{\ensuremath{-}}\mathrm{Mn}$ alloys were fabricated with the textured structure and anisotropic characteristics. Magnetic properties of $\mathrm{MnBi}$ compound aligned in alloys with 6 wt % Mn have been investigated systematically. The saturation magnetization…
A triangular arrangement of gold atoms is observed in the complex [Au3(μ-GaI2)3(Cp*Ga)5], which results when a mixture of Cp*Ga and GaI3 capture the reduced Au fragments from [LAuX] (L=ligand, X=halide). The Au atoms are bonded only to Ga atoms and each other: two Au atoms are coordinated by two Cp*Ga units and one Au…
The AP7 protein is one of several mollusk shell proteins which are responsible for aragonite polymorph formation and stabilization within the nacre layer of the Pacific red abalone, H. rufescens. Previously, we demonstrated that the 30-AA N-terminal domain of AP7, denoted as AP7-1, exists as an unfolded sequence and p…
Perovskite manganite compounds such as ${\mathrm{Pr}}_{1\ensuremath{-}x}{({\mathrm{Ca}}_{1\ensuremath{-}y}{\mathrm{Sr}}_{y})}_{x}\mathrm{Mn}{\mathrm{O}}_{3}$ can be tuned to exhibit a metastable ground state where two magnetic∕crystallographic phases coexist in zero magnetic field. Field-dependent neutron diffraction…
BACKGROUND: Slow crack growth can be described in a v (crack velocity) versus KI (stress intensity factor) diagram. Slow crack growth in ceramics is attributed to corrosion assisted stress at the crack tip or at any pre-existing defect in the ceramic. The combined effect of high stresses at the crack tip and the prese…