Materials Literature
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We report the vibrational spectra of the carbonyl complexes of anionic gold clusters in the range of the CO stretching frequency as measured in the gas phase using IR multiple photon dissociation spectroscopy. The investigated complexes contain between 3 and 14 Au atoms and up to 7 CO ligands. Special attention is giv…
At the heart of the relaxor behavior lies the development of mesoscopic or intermediate range order and the low frequency or relaxation dynamics associated with it. To investigate this development, we have measured the Raman spectra of a $\mathrm{Pb}({\mathrm{Zn}}_{1∕3}{\mathrm{Nb}}_{2∕3}){\mathrm{O}}_{3}$ (PZN) singl…
The surface valence-band densities of states (DOS) of Pt(3)M (M=Ti,V,Cr,Fe,Co,Ni) polycrystalline alloys were investigated with ultraviolet photoemission spectroscopy. Upon annealing the ion-sputter-cleaned alloys at high temperatures, the observed valence-band DOS spectra clearly show the modified electronic structur…
The history of electron emission is reviewed from a standpoint of the work function that determines the electron emission capability and of applications in the fields of scientific instruments and displays. For years, in thermionic emission, a great deal of effort has been devoted to the search for low work function m…
Two types of scaffolds were developed for tissue engineering of the aortic valve; an electrospun valvular scaffold and a knitted valvular scaffold. These scaffolds were compared in a physiologic flow system and in a tissue-engineering process. In fibrin gel enclosed human myofibroblasts were seeded onto both types of…
Success has been obtained in predicting the dynamic evolution of microstructures during phase transformation or cracking propagation by using the time-dependent phase field methodology (PFM). However, most efforts of PFM were made in the elastic regime. In this letter, stress distributions around defects such as a hol…
Abstract This paper reviews our previous studies on the diffusion behavior in polymers clay nanocomposites. A geometric model for predicting the effective diffusivity through this type of systems as a function of clay sheets orientation, volume fraction, polymer clay interaction, and aspect ratio is proposed. Model pr…
The atomic structure of a SrTiO3 dislocation is revealed directly by phase-retrieval electron microscopy. In particular, atomic columns of light oxygen are observed simultaneously with the columns of considerably heavier Sr and Ti. A distinct structural modification of the oxygen octahedra at the dislocation core as w…
Cubic boron nitride (c-BN) thin films are of significant interest because of their diamond like structure and properties. c-BN shows high thermal conductivity, chemical inertness against ferrous metals even at high temperatures, wide band gap, and good transmittance over a wide spectral range from UV to visible. Appli…
We have developed a method to systematically compute the form of Rashba- and Dresselhaus-like contributions to the spin Hamiltonian of heterostructures to an arbitrary order in the wavevector k. This is achieved by using the double group representations to construct general symmetry-allowed Hamiltonians with full spin…
The effect of uniaxial tensile strain on spin coherence in n-type GaAs epilayers is probed using time-resolved Kerr rotation, photoluminescence, and optically-detected nuclear magnetic resonance spectroscopies. The bandgap, electron spin lifetime, electron g-factor, and nuclear quadrupole splitting are simultaneously…
We show that magnetization reversal in spin-injection devices can be significantly faster when using a chirped r.f. rather than d.c current pulse. Alternatively one can use a simple sinusoidal r.f. pulse or an optimized series of alternating, equal-amplitude, square pulses of varying width (a digitized approximation t…
The coupled cluster method (CCM) is a method of quantum many-body theory that may provide accurate results for the ground-state properties of lattice quantum spin systems even in the presence of strong frustration and for lattices of arbitrary spatial dimensionality. Here we present a significant extension of the meth…
A jet of non-Brownian particles confined in a thin cell and driven by gravitational force is studied both numerically and theoretically. We present a theoretical scheme aimed to describe such a system in the Stokes regime. We focus on the dynamics of the interface between the suspension and the pure fluid. Numerical s…
The competing effects of slow structural relaxations (aging) and deformation at constant strain rate on the shear yield stress tau(y) of simple model glasses are examined using molecular simulations. At long times, aging leads to a logarithmic increase in density and tau(y). The yield stress also rises logarithmically…
In recent years there has been an intense search for room temperature ferromagnetism in semiconductors doped with dilute magnetic impurities, in particular, oxides. In this work we study the structural, electronic, and magnetic properties of doped rutile $\mathrm{Ti}{\mathrm{O}}_{2}$ for two different impurity concent…
Using the first principles method, we have investigated the electronic properties of Si-based single-walled nanotubes with different diameters and chiral vectors. The electronic properties show significant difference with those of carbon nanotubes. Si gearlike nanotubes ($g$-NTs) are more stable according to the forma…
TiO2- and gamma-Al2O3-supported Pt catalysts were characterized by HRTEM, XPS, EXAFS, and in situ FTIR spectroscopy after activation at various conditions, and their catalytic properties were examined for the oxidation of CO in the absence and presence of H2 (PROX). When gamma-Al2O3 was used as the support, the cataly…
Dendrimers are a unique class of synthetic macromolecules having a highly branched, three-dimensional, nanoscale architecture with very low polydispersity and high functionality. Structural advantages allow dendrimers to play an important role in the fields of nanotechnology, pharmaceutical and medicinal chemistry. Th…
We report the first controlled synthesis of a layered double hydroxide (LDH) in a water-in-oil reverse microemulsion system. This synthesis of Mg2Al-LDHs was carried out in the reverse microemulsion of NaDDS (sodium dodecyl sulfate)-water-isooctane with water/surfactant molar ratio = 24. This enables us to obtain nano…