Materials Literature
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The use of third-generation synchrotron sources has led to renewed interest in the effect that ionizing radiation has on crystalline biological materials. Simple criteria have been sought to study the effects systematically. The unit-cell volume of protein crystals shows a linear increase with absorbed dose and has th…
A flexible method of preparing and macroscopically aligning nanoparticles of crystalline silver into millimeter long fibers is presented. The approach utilizes the dual functionality of a reverse hexagonal liquid crystalline template containing a built-in reducing agent facing the aqueous domain. The method is advanta…
Competition between microsegregation and rigidity in bolaamphiphilic biphenyl derivatives bearing lateral semiperfluorinated alkyl chains leads to the formation of novel smectic liquid-crystalline phases, designated SmAb and LamA, in which the rigid rodlike segments are organized parallel to the planes of the layers.
Nanoporous shell or sphere-in-sphere structures have been constructed by consecutive alternating adsorption of polyelectrolytes and SiO2 on melamine formaldehyde particles, followed by removal of the cores with HCl and SiO2 with HF. The shells have been distinguished by confocal laser scanning microscopy imaging (see…
Building catalyst models for complex catalytic systems is still a challenging task. In the case of supported bimetallic catalysts, such models can be obtained by taking advantage of nucleation and growth processes during the metal vapor deposition of two metals onto a suitable support (see picture). In this way, the o…
The relationship between molecular structure and electronic properties of 18 N -arylbenzamides has been investigated. The secondary amides adopt extended trans-amide conformations, whereas the tertiary amides adopt folded cis-amide conformations in which the N- aryl group is approximately perpendicular to the benzoyl…
In a recent paper we used a phase-field model of solidification in deeply undercooled pure melts to show that a kinetic instability could result in dendrite tip splitting, and we speculated that such tip splitting could give rise to the phenomenon of spontaneous grain refinement. Here we present evidence, from the as-…
Low ionic sorption capacities and high hydraulic conductivities of sandy soils contribute to the potential for leaching of nutrients applied to these soils. Batch sorption experiments were used to examine NO3–, NH4+, and Psorption/desorption isotherms for Karrakatta sand and Kwinana fly ash. Column experiments assesse…
Three-dimensional micromagnetic simulations are used to study the effect of crystallographic textures on the magnetic properties of uniaxial nanocrystalline films of hard magnetic materials with arbitrary grain shapes and size distributions. The correlation lengths (effective ferromagnetic exchange interaction radius…
We demonstrated a deposition of nanometer-scale Zn dots using the selective photodissociation of adsorption-phase diethylzinc with a nonresonant optical near field, where the photon energy is lower than that of the absorption edge of gas-phase diethylzinc. We achieved nanometric prenucleation by dissociating diethylzi…
The piezoelectric properties of lead zirconate titanate (PZT)–polymer composites were studied as a function of composition and phase connectivity. PZT skeletal structures were fabricated by robotic deposition, densified at 1275 °C, and subsequently infiltrated with epoxy to produce the desired PZT–polymer composites.…
The optical and electrochemical properties of transparent, boron-doped diamond thin film, deposited on quartz, are discussed. The films were deposited by microwave-assisted chemical vapor deposition, for 1-2 h, using a 0.5% CH4/H2 source gas mixture at 45 Torr and 600 W of power. A high rate of diamond nucleation was…
Homocrystallized and amorphous enantiomeric blend films were prepared from the melt of high molecular weight poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) (1:1) by crystallization and quenching, respectively. A phosphate-buffered solution was used to investigate effects of homocrystallinity via in vitro hydrolysis…
Rates of Diels-Alder cycloaddition of anthracenes with p-benzoquinone and its derivatives as well as rates of hydride-transfer reactions from 10-methyl-9,10-dihydroacridine to the same series of p-benzoquinones are accelerated significantly in the presence of metal ions in acetonitrile. An extensive comparison of the…
The introduction of highly intense wiggler and undulator beamlines has reintroduced the problem of X-ray radiation damage in protein crystals even at cryogenic temperatures. Several metrics for monitoring radiation damage are considered and unit-cell volume expansion is systematically investigated using crystals of th…
Radiation-induced degradation of protein or DNA samples by synchrotron radiation is an inherent problem in X-ray crystallography, especially at the 'brighter' light sources. This short review gives a radiation chemical perspective on some of the physical and chemical processes that need to be considered in understandi…
Density-functional theory is used to examine aspects of the copper vacancy (VCu) in cuprous oxide (Cu2O). The normal vacancy configuration, obtained by simple removal of a Cu atom from the lattice, is found to be 0.1 eV higher in energy than a split vacancy configuration wherein a nearby Cu atom is displaced toward a…
Arrays of ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Co}}_{x}$ $(0.0<~x<~1.0)$ nanowires have been fabricated by codepositing Fe and Co into porous anodic alumina. Transmission electron microscope results show that the nanowires are regular and uniform, about $7.5\ensuremath{\mu}\mathrm{m}$ in length and $20\math…
Inhomogeneous polymer-dispersed liquid crystal devices having gradient droplet distribution were fabricated and their phase retardation characterized. The gradient refractive index profile can be used as switchable prism gratings, and positive and negative lenses with tunable focal lengths. Such a tunable electronic l…
An "S"-shaped chiral motif of a p-xylylene-bridged bis(cyclic dipeptide) (1), having four hydrogen-bonding amide functionalities, formed a homochiral supramolecular polymer in solution. X-ray crystallography of a slightly modified version of 1 for an enhanced crystallinity showed one-dimensional columnar assemblies vi…