Materials Literature
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Recent experiments give evidence of a negative refractive index at microwave frequencies in a microstructured material. This discovery may allow some unique features associated with negative- refraction materials to be observed and applied. This letter describes the calculated results for photon tunneling via evanesce…
Photoluminescence (PL) from single silicon quantum dots have been recorded and spectrally resolved at room temperature. The Si nanocrystals (NCs) were fabricated using electron-beam lithography and reactive ion etching resulting in Si nanopillars that were subsequently oxidized to produce luminescent silicon cores. Th…
Neutron powder diffraction experiments on La2/3Ca1/3MnO3 over a broad temperature range above and below the metal-insulator transition have been analyzed beyond the Rietveld average approach by use of Reverse Monte Carlo modelling. This approach allows the calculation of atomic pair distribution functions and spin cor…
A comprehensive study of the exciton relaxation processes in ${\mathrm{Cu}}_{2}\mathrm{O}$ has led to some surprises. We find that the ortho-para conversion rate becomes slower at high stress and that the Auger nonradiative recombination rate increases with stress, with apparently no Auger recombination at zero stress…
The mosacity and optical properties of ZnO on (0001) Al2O3 grown by pulsed-laser deposition have been studied by x-ray diffraction and spectroscopic ellipsometry. Strong dependence has been found between the grain size and the residual strain along the c axis, εzz, as well as the film texture. In general, strain relie…
The Landau-Lifshitz-Gilbert damping coefficient employed in the analysis of spin wave ferromagnetic resonance is related to the electrical conductivity of the sample. The changing magnetization (with time) radiates electromagnetic fields. The electromagnetic energy is then absorbed by the sample and the resulting heat…
The structural properties of amorphous aluminum oxide $({\mathrm{Al}}_{2}{\mathrm{O}}_{3})$ have been investigated by means of the molecular dynamics technique. The simulations were done in a microcanonical ensemble, using a pairwise potential, on systems with up to 1800 particles. Three different systems, at densitie…
We consider viscous shear flow of a monolayer of solid spheres and discuss the effect that microscopic particle surface roughness has on the stress in the suspension. We consider effects both within and outside the dilute régime. Away from jamming concentrations, the viscosity is lowered by surface roughness, and for…
When a bubble collapses mildly the interior pressure field is spatially uniform; this is an assumption often made to close the Rayleigh–Plesset equation of bubble dynamics. The present work is a study of the self-consistency of this assumption, particularly in the case of violent collapses. To begin, an approximation…
We study the dynamical structure factor of gapped one-dimensional spin systems in the critical phase in high magnetic field. It is shown that the presence of a ``condensate'' in the ground state in the high-field phase leads to interesting signatures in the response functions.
Recent experimental observations of anisotropic conductivity in stretched polymer electrolytes films of the polyethylene oxide family are discussed. The main experimental observations, enhancement of the ionic diffusion and conductivity in the stretch direction and decrease in these transport coefficients in the norma…
Poly(2-ethynylthiophene) was stereoregularly prepared with a Rh complex catalyst, [Rh(norbornadiene)Cl] 2, to selectively produce the cis−transoid isomer in high yields when triethylamine was used as the polymerization solvent at 20 °C. Photoinduced cis-to-trans isomerization was newly found to take place when the fil…
5-[[[2‘,5‘-Bis[(4‘ ‘- n -((perfluoroalkyl)alkoxy)benzoyl)oxy]benzyl]oxy]carbonyl]bicyclo[2.2.1]hept-2-enes with short fluorocarbon segments were polymerized by ring-opening metathesis polymerization in THF at room temperature using Mo(CHCMe 2 Ph)(N-2,6- i Pr 2 Ph)(O t Bu) 2 as the initiator. Although hydrocarbon and f…
The electronic structure of the blue-copper site of Pseudomonas aeruginosa azurin has been investigated by ab initio multireference determinantal configuration interaction (MRD-CI) calculations. A truncated site consisting of copper and its three equatorial ligands has been studied with emphasis on the g tensor and th…
Multiple experiments (17O NMR, 1H NMR, and EPR) have been performed in the past to understand the microscopic parameters that control the magnetic relaxation rate enhancement induced by paramagnetic molecules on neighboring water protons, the so-called relaxivity. The generally accepted theories of the electron spin r…
This paper describes the use of dendritic polyglycerol as a new high-loading polymeric support. The soluble polyether skeleton allows the parallel synthesis of small libraries on a large scale (1-5 mmol). Purification of polymer-bound products is easily achieved by a parallel dialysis apparatus, which was developed to…
Single-walled carbon nanotubes can exist in chiral forms and can adsorb a range of molecules. We use atomistic simulations to consider whether enantiopure carbon nanotubes might be effective enantiospecific adsorbents for chiral molecules. We examine the adsorption of both enantiomers of trans-1,2-dimethylcyclopropane…
The processes occurring during annealing of particulate ZnO thin films and powders are examined in detail by size-determining methods (TEM and powder X-ray diffraction) and by thermal analysis. Water and carbon dioxide desorb from the surface at temperatures of about 100 °C. At higher temperatures (between 300 and 500…
The degradation of 4-chlorophenol with near-UV light by silica-immobilized polyoxometalate (POM-in-SiO2) catalysts has been studied. The silica-immobilized Na6W7O24 (SW7), H4W1032 (SW10), H3PW12O40 (SPW12), and H6P2W18O62 (SP2W18) were prepared by means of the sol-gel hydrothermal technique through the hydrolysis of t…
Positively and negatively charged nanoparticles have been mixed together in order to obtain superlattice formation. The interaction between the particles was controlled by adjusting the ionic strength of the solutions. The self-assembly was studied with absorption spectroscopy, powder X-ray diffraction, and high-resol…