Materials Literature
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The FTIR spectrum for a heavily oxidized porous silicon (PS) surface is considered. It is suggested that a portion of this spectrum be reassigned to the Si O stretch frequency of a surface bound-silanone-based silicon oxyhydride consistent also with the 18 O 2 / 16 O 2 isotopic labeling of the FTIR spectrum and with m…
We describe the anisotropic photoreaction of photoreactive side-chain liquid-crystalline polymers (SLCPs), containing biphenyl mesogen and photoreactive cinnamoyl group, by irradiation with a linearly polarized (LP) UV light, and the alignment behavior of the low-molecular-weight (LMW) liquid crystal (LC) on them. The…
A dispersion of fluorescent colloidal silica coated boehmite rods with length $L\ensuremath{\approx}325\mathrm{nm}$ and diameter $D\ensuremath{\approx}46\mathrm{nm},$ dispersed in dimethylformamide, is synthesized. The concentration dependence of the long-time translational self-diffusion coefficient ${D}_{s}^{L}$ is…
Abstract Single‐phase cubic boron nitride films of high quality might be of great importance as superhard wear‐resistant coatings and semiconductive materials. This paper reviews deposition techniques, precursors, deposition parameters and substrates employed in plasma‐assisted CHEMICAL VAPOR DEPOSITION (PACVD) of cub…
A new, relatively inexpensive, easy-to-use instrument has been developed for measuring the thermal conductivity of thin films based on a differential photoacoustic method. Measurements made on silicon dioxide and silicon nitride are consistent with those reported previously for a different technique. In addition, the…
We present some calculated structural and thermodynamic properties of homogeneous-dendritic-polymer solutions using computer simulation methods, integral-equation theory, and lattice-cluster theory. Monte-Carlo methods are used to sample conformations of polymer molecules. From these conformations, we first compute tw…
Abstract The ligand diethyl pyridine‐2, 6‐dicarboxylate ( L 5 ) reacts with Ln III in acetonitrile to successively give the complexes [Ln( L 5 ) i ] 3 + (Ln = La to Lu, i = 1‐3). Spectroscopic investigations (ES‐MS, UV/Vis, NMR) show that the 1:3 complexes [Ln( L 5 ) 3 ] 3 + have poor stability in solution and exist a…
We have studied the temperature dependence of the photoemission spectra of La${}_{1\ensuremath{-}x}$Sr${}_{x}$MnO${}_{3}$ $(x$=0.0, 0.2, and 0.4) and found that the spectral line shape dramatically changes in the entire valence-band region, particularly for $x$=0.2 and 0.4. By contrast, the spectra of La${}_{0.6}$Sr${…
Tetrapod-like ZnO particles having four legs shorter than a micrometre have been observed by transmission electron microscopy and electron diffractometry. The particles are composed of six or more wurtzite-type elements. Four of them make legs and others form (1122) twins with the legs. Particles composed of only four…
Vibrationally resolved photoelectron spectra are obtained for the small TiC x - ( x = 2−5) clusters. Adiabatic electron affinities (EAs) and low-lying electronic states are measured for the neutral TiC x clusters. While the EAs are similar for the series of clusters, 1.542 eV for TiC 2, 1.561 eV for TiC 3, 1.494 eV fo…
Synthetic routes to soluble planar poly(phenylenethiophene)s and polythiophenes are described. The main polymer backbones are synthesized via Pd(0)-catalyzed couplings of the electron-rich N,N ‘-(bis- tert -butoxycarbonyl)-3,4-diamino-2,5-bis(tri- n -butylstannyl)thiophene with electron-deficient aryldibromodiones. Th…
The compounds [Mn 2 (bpm) 3 (NCS) 4 ] ( 1 ), [Mn(bpm)(NCO) 2 ] ( 2 ), and [Mn 2 (bpm)(N 3 ) 4 ] ( 3 ) (where bpm= 2,2‘-bipyrimidine) have been synthesized and characterized. Compound 1 crystallizes in the triclinic P 1̄ space group, with a = 9.122(1) Å, b = 9.229(1) Å, c = 11.710(2) Å, α = 74.89(1)°, β = 80.30(1)°, γ…
Measurements of antiproton stopping powers around the stopping-power maximum are presented for targets of Al, Si, Ti, Cu, Ag, Ta, Pt, and Au. The Low Energy Antiproton Ring antiproton beam of 5.9 MeV is degraded to 50--700 keV, and the energy loss is found by measuring the antiproton velocity before and after the targ…
High-angle annular dark-field (HAADF) images of an Al 72 Ni 20 Co 8 decagonal quasicrystal have been taken for the first time. It has been found that the transition metals form pentagonal and star-shaped cluster columns with radii of about 0.4 nm. The atom-cluster columns with a 2 nm diameter of the alloy, which have…
In this paper we present results from molecular dynamics simulations performed using a system of Gay-Berne particles confined between two substrates in a slab geometry. We use a nonseparable anisotropic molecule-substrate interaction potential and investigate weak and moderate molecule-substrate coupling strengths. We…
Optical properties of Cd y Zn 1 - y S nanoparticles differing by their size and composition are presented. The fluorescence quantum yield increases with increasing particle size and composition ( y ). The photoluminescence, PL, spectra are due to defect states and follow the quantum size effect. A red-shift in the flu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTApplication of X-ray Powder Diffraction Techniques to the Solution of Unknown Crystal StructuresDamodara M. Poojary and Abraham ClearfieldView Author Information Department of Chemistry, Texas A & M University, College Station, Texas 77843 Cite this: Acc. Chem. Res. 1997, 30…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTLarge Variations in 13Cα Chemical Shift Anisotropy in Proteins Correlate with Secondary StructureNico Tjandra and Ad BaxView Author Information Laboratory of Biophysical Chemistry National Heart, Lung, and Blood Institute Laboratory of Chemical Physics National Institu…
We have used scanning force microscopy and transmission electron microscopy to study the microphase separation of P(S- b- 2VP) block copolymers on chemically structured substrates. Gold was patterned by microcontact printing to form regions of self-assembled alkyl monolayers terminated by −CH 3 or −OH. The differences…
A bulk bundle (with a diameter of about 100 µ m) of single-walled nanotubes (SWNTs), which were obtained after a purification process of carbon soot containing SWNTs, was used as an electron emitter. Many spikes of micro-bundles (with a typical diameter of 20–30 nm) of SWNTs extruded from the surface of the bulk emitt…