Materials Literature
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Graphite nanoparticles, with diameters as small as 2 nm (see picture) can be fabricated by the carbonization of polypyrrole nanoparticles of similar dimensions, which have been prepared by a low-temperature polymerization technique in which a micellar microemulsion acts as a “nanoreactor”. The graphite nanoparticles e…
Nanoshells are mesoscopic particles consisting of a dielectric core coated with a metal shell, in particular gold or silver, of uniform nanometer scale thickness. This topology supports plasmon excitations with frequencies that are sensitively dependent on the relative radii of the nanoparticle's core and shell. The p…
Molybdenum blocks in organic polymers: Bifunctionalized hexamolybdate anions (such as 1) can be selectively synthesized in high yields by using the octamolybdate anion 2 as the starting material. The ion 1 can then be used in the synthesis of the first main-chain-polyoxometalate-containing hybrid polymer.
A ferroelectricity-magnetism-coexisting system, hexagonal $R{\mathrm{MnO}}_{3}(R=\mathrm{Y},$ Lu, and Sc), has been investigated by synchrotron x-ray and neutron powder diffraction measurements. It is found from x-ray diffraction measurements that the ferroelectric polarization originates from the tilting of ${\mathrm…
Abstract The chemistry of vulcanization and its effects on vulcanizate properties are reviewed. Also, the chemistry of the protection of rubber vulcanizates from the effects of oxidation and ozonation is reviewed. © 2002 Wiley Periodicals, Inc. J Appl Polm Sci 87:24–30, 2003
Taming the uncontrollable: The novel heteropolymolybdates, such as the [SeIVMo6O21(O2CCH2NH3)3]2− ion shown, functionalized by amino acids, can be derivatized at two different positions in a controlled manner. In addition, further functionalization of the clusters through the amino groups is possible, thus the 18 new…
We have characterized Zn1−xCoxO (x=0.25) films grown on sapphire (0001) substrates by pulsed laser deposition using various growth conditions to investigate the growth condition dependence of properties of Co-doped ZnO films. The substrate temperature (TS) was varied from 300 to 700 °C and the O2 pressure (PO2) from 1…
The mechanical properties of polycrystalline materials are largely determined by the kinetics of the phase transformations during the production process. Progress in x-ray diffraction instrumentation at synchrotron sources has created an opportunity to study the transformation kinetics at the level of individual grain…
The propagation of waves supported by capacitively loaded loops is investigated using a circuit model in which each loop is coupled magnetically to a number of other loops. Since the coupling is due to induced voltages the waves are referred to as magnetoinductive (MI) waves. The mathematical formulations are mostly a…
In the preparation of polymer/clay nanocomposites, organoclay plays an important role in lipophilizing and dispersing the clay into less polar polymer matrixes. Organic modifiers of various chain lengths were examined in different types of clays, smectite, montmorillonite (MMT), and mica, to prepare their correspondin…
Block copolymer lithography makes use of the self-assembling properties of block copolymers to pattern nanoscale features over large areas. Although the resulting patterns have good short-range order, the lack of long-range order limits their utility in some applications. This work presents a lithographically assisted…
A composite medium consisting of an array of fine wires and split-ring resonators has been previously used to experimentally verify a negative index of refraction. We present a negative refractive index (NRI) metamaterial that goes beyond the original split-ring resonator/wire medium and is capable of supporting a bac…
Thermal conductivity of multiwalled carbon nanotubes (CNT's) prepared using a microwave plasma chemical vapor deposition system is investigated using a pulsed photothermal reflectance technique. We find that the average thermal conductivity of carbon nanotube films, with the film thickness from 10 to 50 \ensuremath{\m…
A high pressure photoemission system is described that combines differential pumping with an electrostatic lens system. This approach allows optimized differential pumping without loss of signal, thereby increasing the high-pressure performance by at least 2 orders of magnitude compared to passive differential pumping…
Easily observed on the single molecule level, highly fluorescent and photostable silver nanoclusters have been photochemically prepared within poly(amidoamine) dendrimer hosts in aqueous solutions. The dendrimer cage stabilizes and solubilizes the nanoclusters to yield highly stable, photoactivated single nanodots ran…
We study the origin of the gap and the role of chemical composition in the half-ferromagnetic Heusler alloys using the full-potential screened Korringa-Kohn-Rostoker method. In the paramagnetic phase the ${C1}_{b}$ compounds, like NiMnSb, present a gap. Systems with 18 valence electrons, ${Z}_{t},$ per unit cell, like…
Field electron emission from vertically well-aligned zinc oxide (ZnO) nanowires, which were grown by the vapor deposition method at a low temperature of 550 °C, was investigated. The high-purity ZnO nanowires showed a single crystalline wurtzite structure. The turn-on voltage for the ZnO nanowires was found to be abou…
We present an approach to fabricate solid capsules with precise control of size, permeability, mechanical strength, and compatibility. The capsules are fabricated by the self-assembly of colloidal particles onto the interface of emulsion droplets. After the particles are locked together to form elastic shells, the emu…
The low-temperature behavior of imperfect crystals like KCl with a few ppm of substitutional defects like ${\mathrm{OH}}^{\ensuremath{-}}$ or ${\mathrm{Li}}^{+}$ is dominated by the dynamics of these defects. At low concentrations the defects are usually described as isolated systems. We find that in typical experimen…
The frequency (100Hz–1MHz) and temperature (30–575°C) dependence of electrical properties of calcium doped (Ca = 0.01, 0.05, 0.1) sodium bismuth titanate (NBT) was investigated by impedance spectroscopy. The data is used to analyze the effect of calcium concentration on the electrical properties of NBT. The frequency…