Materials Literature
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A correlation is found between the activity of Au clusters for the catalytic oxidation of CO and the concentration of F-centers in the surface of a MgO support. These results are consistent with recent theoretical results showing that F-centers in MgO serve to anchor Au clusters and control their charge state by parti…
The self-assembly of surfactant-protected gold nanorods (aspect ratio 3.3 +/- 0.3, 20.6 +/- 5.5 nm width, and 67.5 +/- 9.0 nm length) into ordered structures using adipic acid is presented. As made, the gold nanorods are coated with cationic surfactant, which gives them a net positive charge in aqueous solution. The p…
Semiconducting and piezoelectric zinc oxide has two important structure characteristics: the multiple and switchable growth directions: ⟨011¯0⟩, ⟨21¯1¯0⟩, and ⟨0001⟩; and the {0001} polar surfaces. The fast growth directions create nanobelts of different crystallographic facets, and the polar surfaces result in bendin…
The coexistence of ferroelectric and ferromagnetic properties at room temperature is very rarely observed. We have been successful in converting ferroelectric PbTiO3 into a magnetoelectric material by partly substituting Fe at the Ti site. The Pb(Fe1-xTix)O3 system exhibits ferroelectric and ferromagnetic ordering at…
The electronic states of manganese in p-type GaN are investigated using photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies. A series of sharp PL lines at 1.0 eV is observed in codoped GaN and attributed to the intra d-shell transition 4T2(F)-4T1(F) of Mn4+ ions. PLE spectrum of the Mn4+ [4T2(…
To construct an N-representable time-dependent density-functional theory, a generalization to the time domain of the Levy-Lieb (LL) constrained search algorithm is required. That the action is only stationary in the Dirac-Frenkel variational principle eliminates the possibility of basing the search on the action itsel…
We have studied the steady state and dynamic optical properties of semiconductor microdisk lasers whose active region contains interface fluctuation quantum dots in GaAs/(Ga,Al)As quantum wells. Steady-state measurements of the stimulated emission via whispering gallery modes yield a quality factor $Q \sim 5600$ and a…
The interplay between self-diffusion and excitation lines in space-time was recently studied in kinetically constrained models to explain the breakdown of the Stokes-Einstein law in supercooled liquids. Here, we further examine this interplay and its manifestation in incoherent scattering functions. In particular, we…
We have studied the electronic structure of epitaxially grown thin films of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{FeO}}_{3}$ by in situ photoemission spectroscopy (PES) and x-ray-absorption spectroscopy (XAS) measurements. The $\mathrm{Fe}$ $2p$ and valence-band PES spectra and the $\mathrm{O}$ $1…
Polystyrene and poly[( tert -butyl acrylate)- b -styrene] with well-defined molecular weights and polydispersities were prepared by nitroxide-mediated free-radical polymerization. The homopolymers and block copolymers were used to functionalize shortened single-walled carbon nanotubes (SWNTs) through a radical couplin…
Abstract Summary: Octaaminophenyl polyhedral oligomeric silsesquioxane (OapPOSS) was used as a crosslinking agent together with 4,4 ′ ‐methylenebis‐(2‐chloroaniline) to prepare polyurethane networks containing POSS. Fourier transform infrared spectroscopy (FT‐IR), dynamic mechanical analysis (DMA) and thermogravimetri…
Metal bonded cobalt ferrite composites have been shown to be promising candidate materials for use in magnetoelastic stress sensors, due to their large magnetostriction and high sensitivity of magnetization to stress. However previous results have shown that below 60°C the cobalt ferrite material exhibits substantial…
A study of protein resistance of oligo(ethylene glycol) (OEG), HS(CH2)11(OCH2CH2)nOH (n = 2, 4, and 6), self-assembled monolayers (SAMs) on Au(111) surfaces is presented here. Hydroxyl-terminated OEG-SAMs are chosen to avoid the hydrophobic effect observed with methyl-terminated OEG-SAMs, particularly at high packing…
It has been suggested that enhanced anion concentrations at the liquid/vapor interface of airborne saline droplets are important to aerosol reactions in the atmosphere. We report ionic concentrations in the surface of such solutions. Using x-ray photoelectron spectroscopy operating at near ambient pressure, we have me…
Dumbbell-like Au-Fe(3)O(4) nanoparticles are synthesized using decomposition of Fe(CO)(5) on the surface of the Au nanoparticles followed by oxidation in 1-octadecene solvent. The size of the particles is tuned from 2 to 8 nm for Au and 4 nm to 20 nm for Fe(3)O(4). The particles show the characteristic surface plasmon…
Gold octamers (Au8) bound to oxygen-vacancy F-center defects on Mg(001) are the smallest clusters to catalyze the low-temperature oxidation of CO to CO2, whereas clusters deposited on close-to-perfect magnesia surfaces remain chemically inert. Charging of the supported clusters plays a key role in promoting their chem…
New results from the catalyst-free epoxidation route for small alkenes in the homogeneous gas phase using O 3 as the oxidizing agent (Berndt, T.; Böge, O.; Heintzenberg, J.; Claus, P. Ind. Eng. Chem. Res. 2003, 42, 2870.) are presented. The formation of propylene oxide was studied in a wide range of experimental condi…
We report on the discovery of a novel triangular phase regime in the system La1-xSrxMnO3 by means of electron spin resonance and magnetic susceptibility measurements. This phase is characterized by the coexistence of ferromagnetic entities within the globally paramagnetic phase far above the magnetic ordering temperat…
A study of the effects of Bragg peak profiles and nanoparticle size broadening on the real-space pair distribution function (PDF) is presented, using `synthetic' powder diffraction data. Bragg peak profiles from both asymmetric time-of-flight (TOF) spallation neutron data and symmetric synchrotron X-ray data are consi…
Abstract The spontaneous spreading of non‐film‐forming fluids on the surfaces of aqueous solutions of poly(2‐acrylamido‐2‐methyl‐propanesulfonic acid) and its chemically crosslinked gels was studied. The experiments were performed in the same concentration range for the solutions and gels, far above the overlap concen…