Materials Literature
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The exceptional fluorescence properties of single CdSe quantum rods (QRs) arising from internal and external electric fields are studied. Reversible external field induced switching of the emission in single QRs is reported for the first time. This effect was correlated with local field induced emission intensity redu…
We report on the effects of titanium doping (0–7at.%) on the optical and electrical properties of In2O3 using combinatorial deposition and analysis techniques. Maximum mobilities are observed at Ti concentrations of 1.5–2.5at.% and are >80cm2∕Vs in sputtered films. The carrier concentration increased with titan…
The pressure-induced phase transition from wurtzite to rocksalt in ZnO was investigated using first-principles lattice dynamics calculations within the quasi-harmonic approximation. Structural and thermodynamical properties at finite temperatures were well reproduced for both phases. The transition pressure shows nega…
A possibility to realize isotropic artificial backward-wave materials is theoretically analyzed. An improved mixing rule for the effective permittivity of a composite material consisting of two sets of resonant dielectric spheres in a homogeneous background is presented. The equations are validated using the Mie theor…
Dendrimer-like poly(ethylene oxide)s (PEOs) were synthesized by an iterative divergent approach combining anionic polymerization of ethylene oxide from multi-hydroxylated precursors and branching reactions of PEO chain ends. Partial deprotonation of the hydroxyls (< 30%) and use of dimethyl sulfoxide as solvent proved…
We present a model addressing the orientation transition of symmetric block copolymers such as PS/PMMA on smooth and rough surfaces. The distortion free energy of parallel and perpendicular lamellar phases in contact with a rough solid surface is calculated as function of the surface roughness amplitude and wavelength…
We present a novel way of performing kinetic Monte Carlo simulations which does not require an {\it a priori} list of diffusion processes and their associated energetics and reaction rates. Rather, at any time during the simulation, energetics for all possible (single or multi-atom) processes, within a specific intera…
Here we report a study of vortex states in a thin superconducting film with a magnetic dot grown upon it by means of a method based on London-Maxwell equations. Vortices with single quantum flux ($Φ_0 = h c / 2 e$), giant vortices (vortices with multiple flux) as well as antivortices (vortices with negative vorticity)…
We have measured dielectric properties of Ca1+xCu3−xTi4O12 (x=0, 0.1, 0.5, 1, 1.5, 2, 2.9 and 3), and have found that Ca2Cu2Ti4O12 (a composite of CaCu3Ti4O12 and CaTiO3) exhibits a high dielectric constant of 1800 with a low dissipation factor of 0.02 below 100kHz from 220to300K. These are comparable to (or even bett…
Using first-principles total-energy methods, we investigate Jahn-Teller distortions in III-V dilute magnetic semiconductors, GaAs:Mn and GaN:Mn in the cubic zinc blended structure. The results for an isolated Mn impurity on a Ga site show that there is no appreciable effect in GaAs, whereas in GaN there is a Jahn-Tell…
We have employed the first-principles approach to compute the effective response of composites of graded spherical particles of arbitrary conductivity profiles. We solve the boundary-value problem for the polarizability of the graded particles and obtain the dipole moment as well as the multipole moments. We provide a…
This work reports the formation of nano- crystalline Al50Cu28Fe22 by high-energy milling. For obtaining the nano-crystalline material, the Al50Cu28Fe22 alloy synthesized through slow cooling of the molten alloy was subjected to ball milling, which was carried out in attritor mill at 400 rpm for 5 h, 10 h, 20 h, 40 h a…
The targets of the Structural GenomiX (SGX) bacterial genomics project were proteins conserved in multiple prokaryotic organisms with no obvious sequence homolog in the Protein Data Bank of known structures. The outcome of this work was 80 structures, covering 60 unique sequences and 49 different genes. Experimental p…
Dosierter Wirkstoffeinsatz: Hohle mesoporöse Siliciumdioxidpartikel verfügen über eine hohe Wirkstoffspeicherkapazität, und Polyelektrolyt-Mehrfachschichten auf der Partikeloberfläche schalten abhängig vom pH-Wert oder der Ionenstärke die Wirkstoff-Freisetzung. Das Schema illustriert die Freisetzung von Ibuprofen (IBU…
X-ray analysis of ferroelectric thin layers of ${\mathrm{Ba}}_{1∕2}{\mathrm{Sr}}_{1∕2}\mathrm{Ti}{\mathrm{O}}_{3}$ with different thicknesses reveals the presence of strain gradients across the films and allows us to propose a functional form for the internal strain profile. We use this to calculate the influence of s…
Many methods have been proposed for efficient storage of molecular hydrogen for fuel cell applications. However, despite intense research efforts, the twin U.S. Department of Energy goals of 6.5% mass ratio and 62 kg/m3 volume density has not been achieved either experimentally or via theoretical simulations on revers…
We analyzed the glassy-state structural relaxation of polymers near surfaces and interfaces by monitoring fluorescence in multilayer films. Relative to that of bulk, the rate of structural relaxation of poly(methyl methacrylate) is reduced by a factor of 2 at a free surface and by a factor of 15 at a silica substrate…
Keeping drugs under control: Hydrothermally stable, hollow mesoporous silica spheres have a high drug storage capacity, and polyelectrolyte multilayers coated on the spheres act as a switch for drug release which is controlled by the pH or ionic strength of the release medium. The picture shows the release of ibuprofe…
Magnetoelectric multiferroics combine ferromagnetism (a spontaneous magnetization that can be switched by a magnetic field) and ferroelectricity (a spontaneous electric polarization that can be switched by an electric field) in the same phase. They have tremendous potential for applications, not only because they poss…
Microfluidic channels (A) were fabricated by a new GLAD method with thin film porosity engineering capabilities. Smooth areas of a substrate result in fairly compact thin film morphology (C) while areas of the same substrate pre-patterned with a periodic array of seeds (B) are quite porous and permit liquid flow.