Materials Literature
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Branching in semiconductor nanocrystals, which leads to tetrapods and to more complex architectures, is the subject of intensive investigation. Here we support the model according to which branching in CdTe nanocrystals is driven by the formation of multiple wurtzite twins. This is in contrast to previous models for t…
The purpose of this study was to control the fabrication of new labile supramolecular assemblies by formulating associations of DNA molecules with inorganic layered double hydroxides (LDHs). The results show that LDH/DNA hybrids synthesized by a coprecipitation route involving the in situ formation of LDHs around DNA…
Wire-, ribbon-, and sphere-like nanostructures of polypyrrole have been synthesized by solution chemistry methods in the presence of various surfactants (anionic, cationic, or nonionic surfactant) with various oxidizing agents [ammonium persulfate (APS) or ferric chloride (FeCl3), respectively]. The surfactants and ox…
In this work, we present a detailed study concerning the evaluation of the metal-support interaction in high activity gold catalysts for CO oxidation. Using the colloidal deposition method, model catalysts were prepared, which allow the isolation of the effect of the support on the catalytic activity. Prefabricated go…
Abstract Heavily boron doped 1.8 to 2.4 µm thick homoepitaxial diamond films with 1.5 × 10 21 cm –3 ≤ [B] ≤ 1.75 × 10 21 cm –3 have been deposited directly on their (100) Ib substrates at 830 °C. Their cathodoluminescence spectra probe the controlled thicknesses from 0.28 to 2.8 µm, therefore the bulk of the films as…
On the basis of the torque balance equation between the twisting elastic power and the torsional anchoring energy and the Jones matrix equation of twisted nematic liquid crystals (TNLCs), an improved optical method for measuring the azimuthal anchoring strength of NLCs is proposed. In the given experimental setup, the…
Materials science continues to prove to be a fertile ground for innovative research, as demonstrated by the recent Materials Research Society meeting in Boston, which broke records for attendance, and by the continuing success of Advanced Materials , which broke records for submissions, downloads, and published Commun…
Abstract As part of PWR life-time assessment project, a large R&D program, PV-CT50, has been carried out from 1995 to 2004, to assess pressure vessel (PV) steel's toughness curve using very large compact tension (CT) specimens (50 × 125 × 120 mm3) allowing measurements in the ductile to brittle transition range. A…
Periodically stepped NiO(100) surfaces were prepared and characterized with low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption (TPD). Two vicinal NiO(100) single-crystal samples were cut, oriented, and polished with r…
Dynamic simulations of grade transitions are conducted for an industrial fluidized bed polyethylene reactor using a nickel−diimine catalyst. The reactor process model incorporates a kinetic model that predicts polymer properties for nickel−diimine ethylene polymerization. The relationships between reactor process vari…
This Letter reports experimental and numerical results on particle dynamics in an out-of-equilibrium granular medium. We observed two distinct types of grain motion: the well known cage motion, during which a grain is always surrounded by the same neighbors, and low probability "jumps," during which a grain moves sign…
Abstract Ultrasonically initiated miniemulsion polymerization of styrene was conducted in the presence of Fe 3 O 4 nanoparticles. Stable polystyrene (PS)/Fe 3 O 4 nanocomposite emulsions were prepared and magnetic PS/Fe 3 O 4 composite particles were obtained through magnetic separation. The whole procedure comprised…
The physical and biological properties of a water-soluble polymeric contrast agent based on a complex of N-(2-hydroxypropyl)methacrylamide copolymer with gadolinium (HE-24.8) were investigated, and its potential for experimental magnetic resonance (MR) angiography was assessed. Relaxivities of Gd-DTPA-BMA, Gd-DTPA-HSA…
The density anomaly of liquid Ge(0.15)Te(0.85) measured between 633 and 733 K is investigated with ab initio molecular dynamics calculations at four temperatures and at the corresponding experimental densities. For box sizes ranging from 56 to 112 atoms, an 8 k-points sampling of the Brillouin zone is necessary to obt…
Abstract Poly(ethylene glycol) (PEG) and end‐capped poly(ethylene glycol) (poly(ethylene glycol) dimethyl ether (PEGDME)) of number average molecular weight 1000 g mol −1 was melt blended with poly(ethylene terephthalate) (PET) oligomer. NMR, DSC and WAXS techniques characterized the structure and morphology of the bl…
This paper applies the density functional theory to confined liquid crystals comprising ellipsoidal shaped particles interacting through the hard Gaussian overlap (HGO) potential. The restricted orientation model proposed by Rickayzen [Mol. Phys. 95, 393 (1998)] is extended to study the surface anchoring. The excess f…
Abstract A new organic‐soluble aromatic polyimide with biphenyl side‐groups has been synthesized from 4,4′‐oxydiphthalic anhydride and 3,5‐diamino‐benzonic‐4′‐biphenyl ester (DABBE) via a one‐step polymerization in m ‐cresol. A higher molecular weight polyimide has been obtained by the addition of chlorotrimethylsilan…
The first derivative of a new class of perylene bisimide chromophores, N,N'-bis(octyl)-3,9-bis(phenyl)perylene-1,2,7,8-tetracarboxyl bisimide, 1, has been synthesized and its fundamental photophysical and electrochemical properties assessed. The extended, Z-shaped structure was achieved by use of the classic photoenol…
Electrical conductivity measurements were performed on structurally anisotropic thin films deposited using the glancing angle deposition apparatus [K. Robbie and M. J. Brett, J. Vac. Sci. Technol. A 15, 1460 (1997); K. Robbie, J. Sit, and M. J. Brett, J. Vac. Sci. Technol. B 16, 1115 (1998); K. Robbie and M. J. Brett,…
Abstract Poly(ethylene terephthalate) (PET) based blends were obtained by melt blending PET with up to 30 wt% poly(ethylene‐octene) either modified with maleic anhydride (mLLDPE) or not (LLDPE). Both PET/LLDPE and PET/mLLDPE blends were immiscible. The dispersed phase particle size was large in LLDPE blends, but upon…