Materials Literature
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We have carried out time-domain electrostatic force spectroscopy on two different ion-conducting glasses using an atomic force microscope. We compare the electrostatic force spectroscopic data obtained at different temperatures with macroscopic electrical data of the glasses. The overall consistency of the data shows…
Thin films of thermochromic VO2, V1−xWxO2 and V1−x−yWxTiyO2 (x=0.014, and y=0.12) were synthesized onto quartz substrates using a reactive pulsed laser deposition technique. The films were then characterized by x-ray diffraction and x-ray photoelectron spectroscopy. The W and Ti dopant effects on the semiconductor-to-…
A thermodynamic analysis has been carried out to investigate the role of dislocations in ferroelectric materials. Due to the coupling of the stress field of the dislocation and the polarization, there is a drastic variation in the polarization near the dislocation. These polarization gradients result in strong depolar…
We propose an efficient approach within the density-functional theory to determine the phonon structure of infinite solids under finite electric fields. We apply this approach to technological SrTiO$_3$, predicting many unusual properties--including a giant frequency shift, anomalous piezoelectric response, as well as…
The electronic, structural and vibrational properties of small carbon interstitial and antisite clusters are investigated by ab initio methods in 3C and 4H-SiC. The defects possess sizable dissociation energies and may be formed via condensation of carbon interstitials, e.g. generated in the course of ion implantation…
The pi-stacking of oxidized thiophene oligomers is investigated using ab-initio quantum chemistry methods. Dimers of singly-charged oligothiophenes are found to be unstable in the gas phase, but can be stabilized as bound dications in the singlet state by a polarizable solvent such as acetonitrile. Our calculations pr…
Lattice variations and bonding characteristics in rutile TiO2 nanocrystals were examined by x-ray diffraction and x-ray photoelectron spectroscopy. With a reduction in the physical dimensions, rutile TiO2 nanocrystals show a linear lattice expansion and an anomalous covalency enhancement in apparent contradiction to t…
We have investigated carrier transport in a crystalline oxide semiconductor InGaO3(ZnO)5 using single-crystalline thin films. When carrier concentration is less than 2×1018cm−3, logarithm of electrical conductivity decreases in proportion to T−1∕4 and room-temperature Hall mobility was as low as ∼1cm2(Vs)−1. When carr…
Abstract Summary: A feasible method for the preparation of antimicrobial ultrafine fibers with silver nanoparticles was developed by direct electrospinning of a cellulose acetate (CA) solution with small amounts of silver nitrate followed by photoreduction. Silver nanoparticles in ultrafine CA fibers were stabilized b…
Unlike La0.7Ca0.3CoO2.97, Pr0.7Ca0.3CoO3 and Nd0.7Ca0.3CoO2.95 do not show distinct ferromagnetic transitions, but instead they exhibit very low magnetic moments down to 50 K. A detail study of magnetic properties of Pr0.7Ca0.3CoO3 and Nd0.7Ca0.3CoO2.95 shows that the materials are inhomogeneous, exhibiting properties…
We studied the exchange coupling and decoupling occurring in a nanocomposite spin system based on a 3D Heisenberg model by means of Monte Carlo numerical computation simulation. Different from conventional micromagnetism approach which usually adopts finite elements method to compute, in a top-down way, the magnetic p…
The calculation of interatomic magnetic exchange interactions entering the Heisenberg model from the standpoint of the density functional theory (DFT) is outlined for two Fe-based molecular magnets: a trinuclear complex with a Schiff base ligand, which makes an antiferromagnetically coupled frustrated system, and a mo…
We consider pattern formation in periodically forced binary systems. In particular we focus on systems in which the two species are differentially forced, one being accelerated with respect to the other. Using a continuum model consisting of two isothermal ideal gases which interact via a frictional force we demonstra…
The title compound, [Co(C6H4NO2)2(NO2)(H2O)], displays O—H⋯O hydrogen bonds, leading to the formation of a two-dimensional network structure. Interestingly, the oxidation and decomposition of α-pyridoin and the auto-redox reaction of cobalt nitrate occurred during the reaction process.
The nature of the melting transition for a system of hard discs with translational degrees of freedom in two spatial dimensions has been analysed by a combination of computer simulation methods and a finite size scaling technique. The behaviour of the system is consistent with the predictions of the Kosterlitz–Thoules…
A novel method for studying the impurity distribution coefficient in protein crystals was proposed. We observed the impurity distribution in a crystal by a fluorescence method. Conventional electrophoresis can only provide the average effective distribution coefficient ( K eff ) of the whole crystal, but the fluoresce…
Accurate crystal structure analysis at high temperatures is an important challenge in science and technology. A new electric furnace for the measurement of high-resolution (δ d / d = 0.03%) synchrotron radiation powder diffraction profiles from materials at high temperatures (up to 1900 K in air) has been designed and…
Hyperbranched methacrylates were synthesized by self-condensing group transfer polymerization (SCGTP) of 2-(2-methyl-1-triethylsiloxy-1-propenyloxy)ethyl methacrylate (MTSHEMA) and characterized by multidetector SEC and 13 C NMR. Depending on the reaction conditions, molecular weights up to M w = 38 000 at a polydispe…
Hydrogen adsorption measurements on mixed carbon material containing single-walled carbon nanotubes (SWNTs) obtained by the electric-arc method were carried out by three different techniques: a volumetric system, a gravimetric system and an electrochemical method. The found H 2 gas adsorption capacity (volumetric and…
The crystal structure and melting transition of two-dimensional colloids interacting via an anisotropic magnetic dipole–dipole potential are studied. Anisotropy is achieved by tilting the external magnetic field inducing the dipole moments of the colloidal particles away from the direction perpendicular to the particl…