Materials Literature
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We report the first scanning tunneling microscopy (STM) study of single-crystalline anatase. Atomically resolved images of the (101) surface are consistent with a bulk-truncated $(1\ifmmode\times\else\texttimes\fi{}1)$ termination. Step edges run predominantly in the [010], $[1\ifmmode\bar\else\textasciimacron\fi{}11]…
Chiral amide- and urea-type organic gelators (1-6), based on cyclohexanediamine, have been prepared, and the superstructures of the organogels were evaluated by circular dichroism (CD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The CD spectrum of the amide-based organogel system 1…
The combination of the long-lived, spectrally pure emission of YbIII ions with the outstanding light-absorbing capabilities of organic dyes gives photoluminescent lanthanide complexes that are interesting candidates for use as a new class of luminescent labels for molecules of biomedical interest. The water-soluble co…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTRapid and Controlled Polymerization of Lactide by Structurally Characterized Ferric AlkoxidesBrendan J. O'Keefe, Susanne M. Monnier, Marc A. Hillmyer, and William B. TolmanView Author Information Department of Chemistry, University of Minnesota 207 Pleasant Street SE,…
Molecular-dynamics simulations were employed to study deformations on nickel nanowires subjected to uniaxial strain at 300 K using a recently reported embedded-atom (many body) model potential. This embedded-atom model can reproduce exactly the experimental second-order and third-order elastic moduli as well as the ph…
Characterization of a series of correlated electron-spin resonance (ESR) and photoluminescence (PL) lines in diamond grown by chemical vapor deposition is reported. The series consists of a set of structured PL bands in the range 1.8--2.3 eV, and ESR lines due to an $S=1$ center with $g=2.0039(1)$ and $D=35.8(1) \math…
In this paper we investigate theoretically the ground-state NiAs-type structure of MnAs and we compare the magnetic and structural properties with a hypothetical zinc-blende structure. A zinc-blende structure can be obtained, in principle, from the diluted magnetic semiconductor ${\mathrm{Ga}}_{1\ensuremath{-}x}{\math…
Regioregular poly(3-hexylthiophene) (P3HT) produces thermoreversible gel in xylene. The gel is brownish-red in color. SEM and TEM studies indicate the presence of fibrillar network. WAXS and electron diffraction pattern indicate the presence of P3HT crystallites in the gel. The gels exhibit a first-order phase transit…
Oxidation of malate to oxaloacetate in Escherichia coli can be catalyzed by two enzymes: the well-known NAD-dependent malate dehydrogenase (MDH; EC 1.1.1.37) and the membrane-associated malate:quinone-oxidoreductase (MQO; EC 1.1.99.16), encoded by the gene mqo (previously called yojH). Expression of the mqo gene and,…
The electronic properties of carbon nanotubes are investigated in the presence of disorder and a magnetic field parallel or perpendicular to the nanotube axis. In the parallel field geometry, the ${\ensuremath{\varphi}}_{0}$-periodic $({\ensuremath{\varphi}}_{0}=hc/e)$ metal-insulator transition induced in metallic or…
We report high-resolution Compton profiles (CP's) of Al along the three principal symmetry directions at a photon energy of 59.38 keV, together with corresponding highly accurate theoretical profiles obtained within the local-density approximation (LDA) based band-theory framework. A good accord between theory and exp…
Thin films of the charge-ordered (CO) compound ${\mathrm{Pr}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3}$ have been deposited onto (100)-oriented ${\mathrm{SrTiO}}_{3}$ substrates using pulsed laser deposition. Magnetization and transport properties are measured when the thickness of the film is varied. While the thin…
The magnetic interaction of a pair of bound magnetic polarons (BMP) in diluted magnetic semiconductors (DMS) is analyzed via a generalized Hubbard-type Hamiltonian for two carriers in the presence of effective magnetic fields arising from the magnetic polarization of their respective polarons. For the case where the m…
Information on the energy of $5d$ levels of ${\mathrm{Ce}}^{3+}$ in chloride, bromide, and iodide compounds has been collected. From this, values for the centroid shift and the crystal field splitting of the $5d$ configuration are obtained. The centroid shift will be related to the polarizability of the anions and fur…
An elastic model is presented for column buckling of a multiwalled carbon nanotube embedded within an elastic medium. The emphasis is placed on the role of interlayer radial displacements between adjacent nanotubes. In contrast to an existing model which treats the entire multiwalled nanotube as a single column, the p…
The graphitic ribbons with H termination have been the subject of recent studies, but we investigated the ribbons without H termination using tight-binding and first-principles calculations. The ribbons with armchair edge were found to have phonon frequencies near 2000 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ which…
Desorption/ionization on porous silicon mass spectrometry (DIOS-MS) is a novel method for generating and analyzing gas-phase ions that employs direct laser vaporization. The structure and physicochemical properties of the porous silicon surfaces are crucial to DIOS-MS performance and are controlled by the selection of…
Photoluminescence (PL) from surface-oxidized Si nanocrystals (nc-Si) was studied as a function of the size. The size of nc-Si was comparable with or larger than the Bohr radius of free excitons in bulk Si crystal (5 nm). In contrast to smaller surface-oxidized nc-Si (typically as small as a few nanometers in diameter)…
The existing theories which aim to explain the extraordinary optical transmission of a metallic film pierced by a two-dimensional subwavelength hole array [T.W. Ebbesen, H.J. Lezec, H.F. Ghaemi, T. Thio, and P.A. Wolff, Natural (London) 391, 667 (1998)] all have in common the following feature: instead of studying the…
The structure of laser-crystallized thin films of Ge2Sb2+xTe5 (0.0<x⩽1.0) formed by the sputtering method were identified by x-ray diffraction studies to be composed of two phases: one phase is chiefly NaCl type crystal with a lattice constant of about 6 Å and a composition corresponding to Ge2Sb2Te5; the other…