Materials Literature
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New nanoporous carbons with extremely high mesopore volumes and surface areas have been produced using silica nanoparticles as templates. The polymerization of resorcinol and formaldehyde (RF) in the presence of silica sol particles generated RF gel-silica nanocomposites. Carbonization followed by HF etching of silica…
The N -octadecanoyl- L -alanine Langmuir−Blodgett (LB) films deposited from aqueous subphases containing metal ions (Ag +, Zn 2+, Ca 2+, Cd 2+, Ni 2+, and La 3+ ) at their intrinsic pH values are investigated by use of FTIR spectroscopy. The results indicate that hydrogen bond and metal complex play an important role…
X-ray photoelectron spectroscopy was used to estimate the absolute amount of cationic polyelectrolytes that adsorbs on mica and cellulose surfaces in aqueous media. The calculation takes advantage of the knowledge of the mica crystal composition at the basal plane and its ion-exchange properties in aqueous solution. T…
Mass spectra of polystyrene and poly(methylsilsesquioxane)(PMSSQ) derived from methyltriethoxysilane(MTES) were obtained in the 100-1,000 Da range by laser desorption/ionization time-of-flight mass spectrometry using a graphite plate without a matrix. Clean mass spectra were obtained without interference from carbon c…
We report two new hydrogen-bonding-based routes for layer-by-layer fabrication of polymer/Au nanoparticle multilayer thin films. Two types of Au nanoparticles surface-modified with carboxyl groups or pyridine groups were prepared in nonaqueous solvents. In the first assembly route, we consecutively adsorbed poly(4-vin…
When cross-linked by heating or by gamma-irradiation and entrapped in cellulose, whey proteins can generate insoluble biofilms with good mechanical properties and high resistance to attack by proteolytic enzymes. Interchain cross-linking of proteins generated an increase in the puncture strength, and a decrease in wat…
The stabilized jellium model (SJM) provides us a method to calculate the volume changes of different simple metals as a function of the spin polarization, $ζ$, of the delocalized valence electrons. Our calculations show that for bulk metals, the equilibrium Wigner-Seitz (WS) radius, $\bar r_s(ζ)$, is always a n increa…
Pb(Zr 0.53 Ti 0.47 )O 3 (PZT) thin films were prepared on p-type Si(100) substrates with TiO 2 buffer layers. Both the PZT films and TiO 2 buffer layers were deposited by the pulsed laser deposition technique using a KrF excimer laser. The depth profile of the constituent elements observed by Auger electron spectromet…
We report an inelastic light scattering study of the effects of charge ordering on the spin, charge, and lattice dynamics of Bi1-xCaxMnO3 (x>0.5). We find that charge ordering results in anomalous phonon behavior, such as the appearance of "activated" modes. More significantly, however, the transition to the charge-or…
We studied the microscopic kinetics of the amorphous-liquid interface in supercooled laser-melt silicon by means of molecular dynamics computer simulations. The interface velocity was obtained as a function of temperature by direct simulation of the interface motion in an amorphous-liquid model system. The temperature…
Using a magneto-optical indicator film imaging technique and an x-ray topography, we have observed a strong correlation between magnetic and twin structure of a single crystal of La0.7Sr0.3MnO3 (LSMO). The correlation between magnetic and twin domains can be understood in terms of a rhombohedral deformation of the cub…
We propose a mechanism of photostructural changes in amorphous ${\mathrm{As}}_{2}{\mathrm{S}}_{3}$ ( $a\ensuremath{-}{\mathrm{As}}_{2}{\mathrm{S}}_{3}$) on the basis of ab initio molecular orbital calculations on clusters of atoms modeling the local structure of the amorphous system. We have found that trigonal ${\mat…
Transition-metal pentatellurides (HfTe5 and ZrTe5) exhibit a promising power factor (electronic properties) for possible use as a thermoelectric material. For complete characterization of these crystals, thermal conductivity measurements are necessary. In this letter, we report measurements of the thermal conductivity…
We have used differential scanning calorimetry to measure the heat capacity of diamond-like carbon (DLC) film prepared by a plasma immersion ion processing method. The same calorimeter was used to measure the heat capacity of single crystal natural diamond and of high purity graphite. The amount of atomic hydrogen tra…
A Comment on the Letter by Tetsuya Mutou and Hiroushi Kontani, Phys. Rev. Lett. 83, 3685 (1999).
We have studied optical properties of CdS nanocrystals formed by sequential Cd+ and S+ ion implantation into Al2O3 matrices. Two bands related to free excitons in the wurtzite CdS are clearly observed in the absorption spectrum at low temperatures. Efficient photoluminescence (PL) appears near the absorption edge. At…
Electrochemical etching techniques were used to fabricate semiconductor sieves of gallium phosphide, i.e., two-dimensionally nanostructured membranes exhibiting an enhanced optical second harmonic generation (SHG) in comparison with the bulk material. The SHG rotational and fundamental polarization dependencies studie…
A low-cost optical fiber sensor to detect volatile organic compounds has been developed. Changes of up to 13.5 dB in the transmitted optical power have been detected with different concentrations of acetone and dichloromethane vapors. The device uses a standard single-mode fiber. The sensing mechanism relies on a vapo…
Catalytic action of Ni atoms in the growth of single-wall carbon nanotubes is investigated using tight-binding molecular dynamics and ab initio methods. Our results demonstrate this to be a two step process in which the Ni atom first creates and stabilizes defects in nanotubes. The subsequent incorporation of incoming…
We report new zero-field muon spin relaxation and neutron spin echo measurements in ferromagnetic (FM) (La,Ca)MnO3 which suggest at least two spatially separated regions possessing very different Mn-ion spin dynamics. One region displays diffusive relaxation, "critical slowing down" near T(C) and an increasing volume…