Search results for "composite"
showing 10 items of 4584 documents
ESI-FTICR investigation of triethylammonium ion-driven resorcin[4]arene dimer formation and structure
2002
In the course of mass spectrometric measurements a self-assembled hydrogen bonded resorcinarene dimer was observed, the formation of which was driven by the binding of triethylammonium ion as a guest and as an ionic label.
Hydrogen bonded calixarene capsules kinetically stable in DMSO.
2002
Half-life times up to 4 days in DMSO at room temperature are observed for the decomposition of dimeric capsules of urea substituted calix[4]arenes held together by a combination of hydrogen bonds, mechanical entanglement and cation–π interactions.
Highly dispersed encapsulated AuPd nanoparticles on ordered mesoporous carbons for the direct synthesis of H2O2 from molecular oxygen and hydrogen
2012
AuPd nanoparticles (<3 nm) have been encapsulated on the pores of a nanostructured CMK-3 carbon prepared by a nanocasting procedure. This material has been shown to be an excellent catalyst for the direct synthesis of hydrogen peroxide from molecular hydrogen and oxygen.
Encapsulation of diquats by resorcinarenes: a novel staggered anion–solvent mediated hydrogen bonded capsule
2002
Crystallisation studies of ethyl resorcinarene with diquats 2b and 3a (1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane dibromide and 1,4-diazoniabicyclo[2.2.2]octane dichloride, respectively) resulted in hydrogen bonded molecular capsules in which the cations are encapsulated in between the cavities of two resorcinarene molecules and anions are located in the middle of the lower rim ethyl chains.
Pyrogallarenes as alkali metal receptors: the role of cation-pi interactions in complexation.
2006
Crystallization studies of C-methyl pyrogallarene with potassium, rubidium and caesium bromides or chlorides resulted in a hydrogen bonded molecular cage in which the alkali metal cations are eta6 coordinated to aromatic rings via strong cation-pi interactions.
Hydrogen-bonded dimers of a thiacalixarene substituted by carbamoylmethylphosphineoxide groups at the wide rim.
2006
A thiacalix[4]arene derivative bearing four carbamoylmethylphosphineoxide groups at the wide rim forms hydrogen-bonded, dimeric capsules with S8 symmetry in the crystalline state and in apolar solvents, where the inclusion of cationic guests could be proved by 1H NMR and ESI mass spectra.
Genetic rearrangement of the atzAB atrazine-degrading gene cassette from pADP1::Tn5 to the chromosome of Variovorax sp. MD1 and MD2
2007
International audience; We report the characterization of the rearrangement phenomena responsible for the movement of the atrazine-degrading atzA and B genes from pADP1::Tn5 to the chromosome of Variovorax sp. MD1 and MD2. Long PCRs and Southern blot analyses revealed that the two genes forming a gene cassette moved in a unique rearrangement event. It also revealed that the boundaries of the plasmid sequence inserted in the chromosome correspond to IS1071or to sequences close to IS1071. It suggests that this genetic rearrangement could result from the transposition of the composite transposon delimited by IS1071 insertion sequences and containing atzA and atzB genes. In addition, for MD1 an…
Comparison of aggregate stability indices for soil classification and assessment of soil management practices
1989
Summary In view of soil structure analysis and land-use and management history evaluation, several mechanical indices of soil structure were tested on 13 Italian soils. From the wet and dry sieving aggregate distributions, a pseudo-textural aggregation index (Ipta) and a mechanical aggregation index (Ima)) were determined and compared with other soil structure stability indices based on single-sieve analysis. The single-sieve indices S and WSI were good correlated with Ipta and Ima, showing the possibility of substituting the time-consuming aggregate-size distribution determinations. All the soil structure indices were correlated with selected semi-permanent soil characteristics. Soil struc…
XPS study of leached glass surfaces
1990
Abstract By use of a special deconvolution algorithm, it was possible to decompose the XPS O 1s signal into several components reflecting different oxygen bonds. The influence of exposure in vacuo, environmental atmosphere, distilled water, and in a polish solution as corrosive media on the surface of different glasses has been studied. The O 1s signals of fused silica, Na 2 O· n SiO 2 glasses, a BaO·SiO 2 and a BaOB 2 O 3 SiO 2 glass (Schott SK 16) were analyzed. On the glass surfaces, leached layers were formed and analyzed qualitatively and semiquantitatively by XPS and optical and infrared methods. As a reference, virgin surfaces of samples broken in ultrahigh vacuum have been used. T…
Properties of radiation-modified blends of polyethylene with elastomers and liquid crystalline copolyester
2001
The results are given on the effect of γ-irradiation on properties of blends of high and low-density polyethylene (HDPE, LDPE) with elastomers -ethylene/propylene/diene rubber (EPDM) and chlorinated polyethylene (CPE), and thermotropic liquid crystalline polymer (LCP). The morphological, thermal, mechanical properties (including thermosetting properties) and adhesion properties of blended composites were investigated. A special attention was paid to the applicability of the blends as thermosetting materials (TSM). The LCP used was a copolyester of poly(ethylene terephthalate) with p-(hydroxybenzoic acid) in the ratio 40: 60. It was found that addition of LCP essentially influenced the therm…