Materials Literature
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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.
We present the first-principles studies of birefringences of several materials by density-functional theory. They show excellent agreement with experimental results and our approach exhibits its huge potential to make predictions of unknown birefringent properties of optical crystals. We perform the analysis on calciu…
Palette von Blau: Chlorbicyclo[5.3.0]decatrienone sind einfach aus Cycloheptatrienen zugänglich: Cycloaddition von Dichlorketen, Ringerweiterung mit einem Diazoalkan und Dehydrochlorierung in Dimethylformamid. Diese Verbindungen dienen als Zwischenstufen in der regiokontrollierten Synthese einer Vielzahl natürlicher u…
β-Al2TiO5 (dialuminium titanium pentaoxide), grown by rapid cooling of a melt of equimolar amounts of Al2O3 and TiO2, adopts the same overall structure as that crystallized by more conventional methods, such as sintering. Nevertheless, reinvestigation of this structure has resulted in an improved structure model wit…
In order to establish the effect of exchanging one functional group by another on the crystal structure, one would like to be able to search the Cambridge Structural Database for all pairs of crystal structures where this substitution has been made. A program called GRX (group exchange) was written for that purpose.
Solubility was measured in the Na−F−SO 4 system at 25 °C and at 50 °C. Pure-component solubilities for NaF and Na 2 SO 4 are in agreement with available literature data at 25 °C and at 50 °C. The influence of sodium hydroxide on the solubility of the sodium−fluoride−sulfate double salt (Na 3 FSO 4 ) was also examined.…
The attenuation and velocity of ultrasonic waves of frequencies in the range of $10\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}70\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$ have been measured in ${({\mathrm{Li}}_{2}\mathrm{O})}_{x}{({\mathrm{B}}_{2}{\mathrm{O}}_{3})}_{1\ensuremath{-}x}$ borate glasses…