Materials Literature
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Unique affine extensions H aff 2 , H aff 3 and H aff 4 are determined for the noncrystallographic Coxeter groups H 2 , H 3 and H 4 . They are used for the construction of new mathematical models for quasicrystal fragments with tenfold symmetry. The case of H aff 2 corresponding to planar point sets is discussed in det…
The effects on the electrical properties of Si doping into Cu2O thin films deposited by reactive sputtering were studied. The hole density increased from 1×1015 to 1×1017 cm−3 with increasing Si content and the minimum resistivity obtained was 12 Ω cm. It was suggested that the electrically active acceptor with an act…
Experiments are presented elucidating how the evolution of foam microstructure by gas diffusion from high to low pressure bubbles can significantly speed up the rate of gravitational drainage, and vice versa. This includes detailed data on the liquid-fraction dependence of the coarsening rate, and on the liquid-fracti…
The random energy model (REM) has become a key reference model for glassy systems. In particular, it is expected to provide a prime example of a system whose dynamics shows aging, a universal phenomenon characterizing the dynamics of complex systems. The analysis of its activated dynamics is based on so-called trap mo…
A novel molecular spin ladder structure of a nickel dithiolate complex has been constructed using a supramolecular cation composed of anilinium and 18-crown-6.
Abstract Copolymerizations of styrene and the polyhedral oligomeric silsesquioxane (POSS)–styryl macromonomer 1‐(4‐vinylphenyl)‐3,5,7,9,11,13,15‐heptacyclopentylpentacyclo [9.5.1.1 3,9 .1 5,15 .1 7,13 ] octasiloxane have been performed with CpTiCl 3 in conjunction with methylaluminoxane. Random copolymers of syndiotac…
Individual large-diameter (∼3 to 5 nm) semiconducting single-walled carbon nanotubes (SWNTs) are found to exhibit ambipolar field-effect transistor (FET) behavior, with easily accessible n- and p-conduction channels by simple electrostatic gates. The effects of temperature and ultraviolet radiation on their electrical…
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…