Materials Literature
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The use of time-resolved 337 nm and 248 nm laser flash photolysis with transient absorbance detection has shown direct evidence of electron transfer from dGMP to the triplet state of riboflavin (3RF*). dGMP was used as a DNA model system in order to study the damaging potential of photoexcited riboflavin. The evidence…
Clay–polyimide [3,3′, 4,4′-benzophenone tetracarboxylic dianhydride–4,4′-oxydianiline (BTDA–ODA)] nanocomposites were synthesized from ODA-modified montmorillonite (organoclay) and poly(amic acid). The layered silicates of organoclay were intercalated by polyimide (BTDA–ODA), as confirmed by X-ray diffraction and by t…
The aromatic pathways of free-base porphins, chlorins and bacteriochlorins have been studied by calculating the nuclear magnetic shieldings at selected points outside the molecules. The strengths of the induced ring currents for a given magnetic field have been obtained by using the aromatic ring current shieldings (A…
Hexagonal mesoporous silica layers were prepared by the sol–gel route using silicon alkoxides as silica precursors and alkyltrimethylammonium bromides to form the templating liquid crystal mesophase. The synthesis conditions required to obtain well-ordered crack-free layers were investigated. Thin layers exhibiting th…
Ordered, hydrothermally stable mesoporous molecular sieve SBA-15 with hexagonal channel porosity has been synthesized for the first time under microwave–hydrothermal conditions from aged precursor gel within 15 min at 373 K; the crystallized product has been characterized using X-ray diffraction, nitrogen adsorption–d…
The Raman spectrum of vaterite prepared by electrochemical scaling in carbonically pure water is presented and analysed following the rules of group theory. It is shown that only one of the three crystallographic determinations already proposed for the structure of vaterite is compatible with the results obtained. The…
Carbon catabolite repression allows bacteria to rapidly alter the expression of catabolic genes in response to the availability of metabolizable carbon sources. In Bacillus subtilis, this phenomenon is controlled by the HPr kinase (HprK) that catalyzes ATP-dependent phosphorylation of either HPr (histidine containing…
Ta2O5 ceramics and crystals were prepared and analyzed using Raman spectroscopy in the temperature range 25–873 K. The low-energy phonon bands (ν < 100 cm−1) of Ta2O5 are assigned to external modes originating from the interaction between different Ta polyhedra and TaOn5 − 2n Ta6O126+ clusters. The temperature and po…
We show that dissociative oxygen adsorption on Ag(001) induces below room temperature a missing row $2\sqrt{2}\ifmmode\times\else\texttimes\fi{}\sqrt{2}$ reconstruction of the substrate. As demonstrated by the analysis of the photoelectron diffraction patterns, the oxygen atoms sit thereby in a $c(2\ifmmode\times\else…
Electronic components and materials are systematically presented, including the categories, develop cause and especially the latest new development.
The reaction of AuCl(THT) (1) with long chain primary amines (CnH2n+1NH2; n = 8, 12, 16) leads to the formation of the complexes AuCl(NH2R) (R = C8H17, 2; C12H25, 3; C16H33, 4) which are characterized by classical methods and shown to self-organize in the solid state into a fibrous material; decomposition of the compl…
The triple helix is a specialized protein motif, found in all collagens as well as in noncollagenous proteins involved in host defense. Peptides will adopt a triple-helical conformation if the sequence contains its characteristic features of Gly as every third residue and a high content of Pro and Hyp residues. Such m…
This paper describes the use of temperature dependent FTIR spectroscopy and molecular modelling studies to establish the origin and the nature of surface hydroxyl ions on calcium carbonate. It has been demonstrated that two types (Type I, corresponding to a band at 3690 cm−1 and Type II, corresponding to a band at 364…
The fire-resistance of EVA filled with ternary systems (magnesium hydroxide/zinc borate/talc) has been investigated. The release of water from Mg(OH)2 seemed to be the predominant phenomenon which acts in relation to fire-resistance. The presence of talc as a minor component, mainly in binary compositions by partial s…
The generation of dense silica microspheres (density 2.14 ± 0.02 g cm−3; 95–98% of theoretical value) from the hydrolysis and condensation reactions of Si(OC2H5)4 (TEOS) in the presence of a fixed concentration of acetic acid and water (TEOS ∶ CH3COOH ∶ H2O = 1 ∶ 4 ∶ 4) were studied by FTIR absorption spectroscopy, pa…
Abstract Over a twenty-year period, condensed matter physicists and physical chemists have elucidated a series of scaling laws which successfully describe the size dependence of solid state properties [1,2]. Often the experiments were performed under somewhat exotic conditions, for instance on mass-selected clusters i…
This paper addresses the modeling of hysteresis and nonlinear constitutive relations in piezoelectric materials at moderate to high drive levels. Hysteresis and nonlinearities are due to the domain structure inherent to the materials and both aspects must be addressed to attain the full potential of the materials as s…
Nanocomposite films can be deposited by electrochemical deposition of a material from a solution containing a suspension of nanometer size particles. We show that the kinetics of nanometer size particle incorporation into a growing film can be described by a model that takes into account the convective diffusion of pa…
Intercalation and exfoliation behavior of organoclays in epoxy resin has been studied through XRD and DSC. It was found that the organoclays were easily intercalated by epoxy oligomer to form a stable epoxy/clay intercalated hybrid. Under appropriate conditions the clays were able to be further exfoliated as the epoxy…
Titania nanosheet crystallites have been self-assembled layer-by-layer with poly(dimethyldiallyl ammonium chloride) onto substrates to produce ultrathin nanostructured films which exhibit highly efficient optical absorption with a sharp peak at 266 nm.