Materials Literature
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A new switching molecular array that interconverts reversibly either by thermal means (valence tautomerism) or by a reversible oxidation process has been established. Such an array is based on the rich electrochemical behavior of the cobalt Schiff base complex 2. The Schiff base ligand can exist in different oxidation…
The dielectric response of pulsed laser ablated barium strontium titanate thin films were studied as a function of frequency and ambient temperature (from room temperature to 320 °C) by employing impedance spectroscopy. Combined modulus and impedance spectroscopic plots were used to study the response of the film, whi…
Here we report the observation of a linear carbon-atom chain, synthesized using an arc discharge from a graphite double anode. We use high-resolution TEM to evidence the formation of a carbon-atom chain along the axis of a needlelike structure consisting of concentric cylindrical graphitic shells. The atomic chain in…
First-principles molecular orbital calculations using model clusters are made in order to reproduce and interpret experimental electron-energy-loss near-edge structure and near-edge x-ray absorption fine structure of MgO at Mg K, ${L}_{2,3}$ and O K edges. Ground-state calculations using a model cluster composed of 12…
Polydisperse brushes obtained by reversible radical chain polymerization reaction onto a solid substrate with surface-attached initiators are studied by means of an off-lattice Monte Carlo algorithm of living polymers (LP). Various properties of such brushes, like the average chain length and the conformational orient…
Oxidative stress has been implicated as a primary cause of neuronal death in certain neurodegenerative disorders and in aging brains. Natural products have been used in Asian societies for centuries for treating such neurodegenerative disorders as senile dementia. In an effort to identify active neuroprotective compou…
The optical transmittance of Ge:Sb:Te evaporated thin film alloys with different compositions was measured in the wavelength range from 2.5 to 34 μm. The as-deposited films with an amorphous structure were thermally crystallized to achieve the two known crystalline phases: the fcc and the hexagonal at higher treatment…
The photodissociation of benzoin diethyl phosphate ( 1, “caged” phosphate) was studied by nanosecond and picosecond laser flash photolysis. The lowest triplet state of 1, 3 1, was identified as the reactive excited state with an absorption maximum around 340 nm and a lifetime of 10−25 ns, depending on the solvent. Two…
We investigate the electronic structure of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{VO}}_{3}$ for various values of x. ${\mathrm{LaVO}}_{3}$ is a Mott-Hubbard insulator with band gap of about $1.0\ifmmode\pm\else\textpm\fi{}0.2\mathrm{eV}.$ Hole doping in this system leads to the growth of a new feat…
A study was made on the effects of polymerization conditions on the long-chain branching, molecular weight, and end-group types of polyethene produced with the metallocene-catalyst systems Et[Ind]2ZrCl2/MAO, Et[IndH4]2ZrCl2/MAO, and (n-BuCp)2ZrCl2/MAO. Long-chain branching in the polyethenes, as measured by dynamic rh…
The electronic structure and bonding of ${\mathrm{Gd}}_{3}{\mathrm{Sc}}_{2}{\mathrm{Ga}}_{3}{\mathrm{O}}_{12}$ (GSGG), ${\mathrm{Gd}}_{3}{\mathrm{Sc}}_{2}{\mathrm{Al}}_{3}{\mathrm{O}}_{12}$ (GSAG), and ${\mathrm{Gd}}_{3}{\mathrm{Ga}}_{5}{\mathrm{O}}_{12}$ (GGG) crystals with a garnet structure are studied by means of…
The electronic structure of ${\mathrm{InGaZnO}}_{4},$ which has a layered structure with alternating laminated layers of ${\mathrm{InO}}_{2}$ and ${\mathrm{GaZnO}}_{2},$ was calculated in order to investigate the mechanism of electrical conductivity. In the crystal structure obtained through relaxation calculations us…
Amorphous FeCoB alloys can have high resistivity and relatively high saturation magnetization which are desired for ultrahigh frequency devices such as future write heads and wireless inductors. In this study, FeCoB films are observed to have a low easy axis coercivity (1–2 Oe), a field deposited induced anisotropy of…
We have performed dc transport and optical conductivity measurements on purified and potassium doped thick films of single walled carbon nanotubes. The pristine sample is characterized by a metallic (Drude) response of the optical properties despite the non-metallic behavior in the dc resistivity measurements. Even th…
Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) were used to investigate the local structure of Pd supported on ZSM-5, which was affected by the acid sites of support and the adsorption of nitrogen oxide. After the thermal treatment of the initially ion-exchanged Pd am…
Analytical second derivatives for combined QM/MM calculations have been formulated and implemented in the CHARMM program interfaced with the ab initio quantum mechanical GAMESS and CADPAC programs. This makes possible evaluation of vibrational frequencies and infrared intensities in large systems that cannot be treate…
The atomic structure of a carbon nanotube can be described by its chiral angle and diameter and can be specified by a pair of lattice indices $(n,m).$ The electronic and mechanical properties are critically dependent on these indices. Scanning tunneling microscopy (STM) is a useful tool to investigate carbon nanotubes…
We combine a density functional theory (DFT) with a self-consistent field model (SCF) to calculate the phase behavior of thin, oblate colloidal particles that are coated with surfactants and dispersed in a polymer melt. These coated particles represent organically modified clay sheets. By integrating the two methods,…
The structure of amorphous carbon at densities of 2.0, 2.6, 2.9, and 3.2 ${\mathrm{g}/\mathrm{c}\mathrm{m}}^{3}$ has been investigated using Car-Parrinello ab initio molecular dynamics. The networks were generated by rapidly cooling samples of 125 atoms to form a solid amorphous structure. The important structural att…
The authors have shown accelerated endothelialization on polyethylene terephthalate (PET) grafts preclotted with autologous bone marrow. Bone marrow cells have a subset of early progenitor cells that express the CD34 antigen on their surfaces. A recent in vitro study has shown that CD34(+) cells can differentiate into…