Materials Literature
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We have synthesized linear poly(lactic acid) (BHMBA−PLA) possessing a pendent carboxylic acid group via ring-opening polymerization (ROP) of l - or d, l -lactide using bis(hydroxymethyl) butyric acid (BHMBA) as initiator and stannous octoate as catalyst. Polymerizations were typically conducted in the bulk for ∼3 h at…
We present the results of experiments on the optical, electrical and magnetic properties and electronic structure and optical spectrum calculations of the Heusler alloys Fe 2 TiAl, Fe 2 VAl and Fe 2 CrAl. We find that the drastic transformation of the band spectrum, especially near the Fermi level, when replacing the…
In this paper, thermal treatment of Zn(NH 3 ) 4 2+ precursor in ethanol solvent leading to the formation of the ZnO hollow spheres is reported. It was demonstrated that the pH value of the initial mixture and the volume ratio of the ethanol with the solution plays the key function in the formation of hollow spheres. T…
By means of the ab initio all-electron new full-potential linear-muffin-tin orbitals method, calculations were made for elastic constants C 11 , C 12 and C 44 for Si, ZrO 2 and HfO 2 in their cubic phase, and constants C 11 , C 22 , C 33 , C 12 , C 13 , C 23 , C 44 , C 55 and C 66 for HfO 2 in its orthorhombic phase.…
Mg2B2O5 nanowires with (010) twins were synthesized for the first time using a catalyst-free method. The microstructure of the Mg2B2O5 nanowires has been extensively studied by cross-sectional high-resolution transmission electron microscopy. Nanoindentation tests were performed directly on individual nanowires to pro…
More than a pretty phase: A class of helical β-peptides has been discovered that form lyotropic liquid-crystalline (LC) phases in water. The β-peptide sequence strongly affects the mode of assembly and ultimately whether a LC phase is formed. For a non-globally amphiphilic β-peptide that can form a LC phase, cryo-TEM…
Shapeshifters: The shape and size of gold nanocrystals were controlled simultaneously through directed surface overgrowth from polyhedral and spherical seeds of different sizes. The resulting cubes, cuboctahedra, and octahedra (shown as SEM images for growth from spherical seeds of two sizes) exhibited characteristic…
Based on first-principles calculations, we have investigated electronic structures and magnetic properties of SnO 2 doped with V, Mn, Fe, and Co. Our results show that ferromagnetism is the ground state and that the Curie temperatures are expected to have high values for Fe- and Co-doped SnO 2 , which is in good agree…
We report the magnetoresistance (MR) properties of quasi-two-dimensional mesoscopic graphite (MG) spin valve devices consisting of MG flakes contacted by ferromagnetic (FM) electrodes. For devices in which an ultrathin magnesium oxide $(\mathrm{MgO})$ tunnel barrier is inserted at the FM/MG interface, the spin valve e…
We studied the temperature and excitation intensity dependence of exciton luminescence in individual single-walled carbon nanotubes (SWNTs) using single nanotube photoluminescence (PL) spectroscopy. The linear temperature dependence of the PL linewidth in a single SWNT implies that the exciton dephasing is dominated b…
Asymmetric nanocomposite particle pairs of polystyrene and silica were prepared via one-step miniemulsion polymerization for the first time. The transmission electron microscopy images showed that these nanocomposite particle pairs were monodisperse and highly asymmetric in morphology. The key to obtaining the asymmet…
The coupling between $z$ valleys in the conduction band of a Si quantum well arises from phenomena occurring within several atoms from the interface, thus ruling out a theoretical description based on pure effective mass theory. However, the complexity and size of a realistic device precludes an analytical atomistic d…
A sample preparation method based on convective assembly for "whole-microorganism" identification using surface-enhanced Raman scattering (SERS) is developed. With this technique, a uniform sample can easily be prepared with silver nanoparticles. During the deposition process, bacteria and nanoparticles are assembled…
Nano granular metallic iron (Fe) and titanium dioxide (TiO$_{2-δ}$) were co-deposited on (100) lanthanum aluminate (LaAlO$_3$) substrates in a low oxygen chamber pressure using a pulsed laser ablation deposition (PLD) technique. The co-deposition of Fe and TiO$_2$ resulted in $\approx$ 10 nm metallic Fe spherical grai…
In the first part of this series of two papers, we proposed a theoretical formalism that enables one to model and categorize heterogeneous materials (media) via two-point correlation functions S2 and introduced an efficient heterogeneous-medium (re)construction algorithm called the "lattice-point" algorithm. Here we d…
We report observations of tunneling anisotropic magnetoresitance (TAMR) in vertical tunnel devices with a ferromagnetic multilayer-(Co/Pt) electrode and a non-magnetic Pt counter-electrode separated by an AlOx barrier. In stacks with the ferromagnetic electrode terminated by a Co film the TAMR magnitude saturates at 0…
The orbital magnetic moment of a Co adatom on a Pt(111) surface is calculated in good agreement with experimental data making use of the LSDA+U method. It is shown that both electron correlation induced orbital polarization and structural relaxation play essential roles in orbital moment formation. The microscopic ori…
We use the parabolic wave equation to study the propagation of x-rays in tapered waveguides by numercial simulation and optimization. The goal of the study is to elucidate how beam concentration can be best achieved in x-ray optical nanostructures. Such optimized waveguides can e.g. be used to investigate single biomo…
We present a first-principles atomistic thermodynamics framework to describe the structure, composition and segregation profile of an alloy surface in contact with a (reactive) environment. The method is illustrated with the application to a Ag3Pd(111) surface in an oxygen atmosphere, and we analyze trends in segregat…
We have employed conventional ab initio and density-functional-theory (DFT) methods to study the structure, stability and electric polarizability of small gallium arsenide clusters ${\mathrm{Ga}}_{n}{\mathrm{As}}_{n}$. We relied on purpose-oriented, carefully optimized basis sets of Gaussian-type functions. We have ca…