Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
We report on the surface behavior of the asymmetric heteroarm poly(ethylene oxide) (PEO)/polystyrene (PS) star polymer on the air−water interface on a solid substrate. These amphiphilic star polymers with different numbers of hydrophobic arms and a similar hydrophilic block differ by architecture (four and three arm m…
The structures and electrochemistry of N-benzylated meso-tetrakis (3,5-di-tert-butyl-4-oxo-cyclohexa-2,5-dienylidene) porphyrinogens have been investigated. Structural determinations reveal the isomeric identity of the products obtained from the N-alkylation of the parent meso-tetra (oxo-cyclohexadienylidene) porphyri…
An original synthetic approach to Au/TiO 2 nanosystems is developed. The adopted technique is based on the RF-sputtering of gold ( guest ) on porous titania xerogels ( host ) obtained by the sol−gel route. Such a combined synthetic pathway joins the peculiarities offered by the features of the sol−gel layers (porosity…
The hydrothermal synthesis and structural characterization of layered lanthanide silicates, K(3)[M(1-a)Ln(a)Si(3)O(8)(OH)(2)] (M = Y(3+), Tb(3+); Ln = Eu(3+), Er(3+), Tb(3+), and Gd(3+)), named AV-22 materials, are reported. The structure of these solids was elucidated by single-crystal (180 K) and powder X-ray diffra…
After adsorption on a silicon substrate, coiled multiwalled nanotubes retain a 3D structure with sections of freely suspended windings. Electrical gold contacts attached to the nanotubes turn out to be sensitive to vibrations (i.e., the contacts reveal a piezoresistive-like response). When exciting the nanotube windin…
The structure and energetics of thin water overlayers on the (101) surface of TiO(2)-anatase have been studied through first-principles molecular dynamics simulations at T = 160 K. At one monolayer coverage, H(2)O molecules are adsorbed at the 5-fold Ti sites (Ti(5c)), forming an ordered crystal-like 2D layer with no…
The chemical synthesis of polyaniline (PANI) is explored using tetrachloroaurate, AuCl 4 - . These studies provide a simple method for the oxidation of aniline by AuCl 4 - and simultaneous formation of bulk quantities of a PANI/Au composite. In situ UV/vis spectroscopy indicates that the rate of formation of gold coll…
Abstract For the homogeneous precipitation of hydrotalcite-like compounds (layered double hydroxides; LDHs), HMT (hexamethylenetetramine) was used and the conditions for obtaining the LDHs were investigated. The well-crystallized 1–5 μm LDHs were obtained in a pressure vessel after a 1-day treatment at 140 °C. The res…
[reaction: see text] Nineteen Mn(II) complexes were screened for the catalytic epoxidation of terminal olefins using peracetic acid. Few of these complexes are efficient catalysts at pH < 2, but many are effective at 1 mol % catalyst loading at pH 4. With 0.1 mol % loading, four complexes epoxidize 1-octene in approxi…
Luminescence temperature antiquenching (LTAQ) is observed for water-soluble CdTe quantum dots (QDs) capped with aminoethanethiol (AET). The efficient exciton emission (quantum efficiency of approximately 40% at 300 K) is quenched almost completely as the QD solutions are cooled to below 230 K and is fully recovered ar…
Flat arrays (rafts) of aligned silver nanowires were fabricated by electrodepositing silver in the nanopores of highly ordered anodic alumina templates and then releasing the silver nanowires and depositing them on an oxidized, single-crystal silicon surface. SERS spectra were recorded from Rhodamine 6G molecules adso…
ZnS nanowaveguides with rectangular cross-section (∼50 × 50 nm 2 ) and tens of microns in length have been synthesized by pulsed laser vaporization of ZnS/10% Au targets in a flow of Ar/5% H 2 . The highly crystalline filaments exhibit the wurtzite structure, growing mainly along the [001] or [100] directions. Photolu…
The development of thin films and coatings that control the release of DNA from the surfaces of materials could have a significant impact on localized approaches to gene therapy. Here, we report multilayered polyelectrolyte assemblies that sustain the release of functional plasmid DNA from the surfaces of model substr…
Abstract Air‐filled microballoons of poly(dimethylsiloxane), ie PDMS, have been encapsulated in polyimide. The molecular assembly so formed has shown surface dominance by PDMS while analytical techniques, such as X‐ray photoelectron spectroscopy and infrared spectroscopy, have confirmed a similar distribution in the b…
Abstract Poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) (PHBV) was irradiated by 60 Co γ‐rays (doses of 50, 100 and 200 kGy) under vacuum. The thermal analysis of control and irradiated PHBV, under vacuum was carried out by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The tensile prope…
Abstract A new series of segmented copolymers were synthesized from poly(ethylene terephthalate) (PET) oligomers and poly(ethylene glycol) (PEG) by a two‐step solution polymerization reaction. PET oligomers were obtained by glycolysis depolymerization. Structural features were defined by infrared and nuclear magnetic…
(S)-Mandelate dehydrogenase from Pseudomonas putida belongs to a FMN-dependent enzyme family that oxidizes (S)-alpha-hydroxyacids. Despite a high degree of sequence and structural similarity, this family can be divided into three subgroups based on the different oxidants utilized in the second oxidative half-reaction.…
The origin of a deep pseudogap existing at the Fermi level ${E}_{\mathrm{F}}$ in the ${\mathrm{Al}}_{52.5}{\mathrm{Li}}_{32.5}{\mathrm{Cu}}_{15}$ $1∕1\text{\ensuremath{-}}1∕1\text{\ensuremath{-}}1∕1$ approximant was studied from two different points of view of orbital hybridizations and the Fermi surface--Brillouin zo…
The reaction between adsorbed CO molecules and O atoms on epitaxially grown RuO 2 (110) was investigated by scanning tunneling microscopy. Two types of titration experiments were performed at 300 K, in which either CO was dosed on the stoichiometric oxide surface, or O 2 on the CO saturated surface. In both cases, rea…
The dilution effects of the precursor methane atmosphere by three noble gases (Ar, Ne and He) on the mechanical properties and the microstructure of hydrogenated amorphous carbon films deposited by rf-PECVD were studied. The chemical composition and atomic density of the films were determined by ion beam analysis. The…