Materials Literature
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The temperature dependence of the vibrational wavenumbers, of the anharmonic and/or order–disorder origin of the damping and of the Raman intensities are briefly presented. On that basis, it is then shown that one can obtain information such as the height of the potential barrier, the orientational correlation time, t…
Surface and interface stresses, which are intrinsic thermodynamic quantities associated with all types of solid surfaces and interfaces, are reviewed. These stresses can significantly modify the thermodynamics of small scale solids as well as result in significant variations in the structure and physical behavior of m…
Using ab initio quantum-chemical and density functional methods we have determined novel structures of bare boron clusters. In addition to previously reported quasi-planar, convex and spherical cluster forms, boron nanotubules seem to be highly stable as well. These novel nanotubular structures are composed of hexagon…
We use a molecular dynamics simulation to investigate the properties and design space of molecular gears fashioned from carbon nanotubes with teeth added via a benzyne reaction known to occur with . Brenner's reactive hydrocarbon potential is used to model interatomic forces within each molecular gear. A Lennard - Jon…
Composite nanoclusters of gold and CdS with core/shell geometry have been synthesized using a chemical precipitation method in aqueous media. These nanoclusters are photoactive and exhibit transient bleaching in the 400−600 nm region when subjected to 355 nm laser pulse excitation. Capping of gold colloids with ultras…
The surface diffusion rate of bacterial cellulases from Cellulomonas fimi on cellulose was quantified using fluorescence recovery after photobleaching analysis. Studies were performed on an exo-beta-1-4-glycanase (Cex), an endo-beta-1-4-glucanase (CenA), and their respective isolated cellulose-binding domains (CBDs).…
Face-centred cubic metals deform by slip until the flow stress and dislocation density are very high, under certain conditions deformation may then proceed by twinning. The geometrical relation between the parent and twinned lattices has been studied in detail (1, 2). In the present work, the dislocation substructures…
Effects of the composition on the afterglow characteristics of phosphors have been evaluated using crystals grown by a floating zone technique for the first time. Phosphorescence spectrum due to ions peaking at λ = 520 nm does not vary with the compositions. Persistent times vary greatly with different compositions. D…
For describing the dislocation pattern formation, two different approaches are applied. In one of them the collective behavior of many individual dislocations is investigated by analytical or numerical methods, in the other one the dislocation system is described by continuous functions of the space coordinates. A met…
Despite many years of research, the detailed atomic structure of many important carbon materials remains poorly understood. In particular, the structure of those carbons which can not be transformed into graphite by high temperature heat treatment has never been clearly established. These non-graphitising carbons are…
High-resolution electron microscopy is used to study the structure of two typical non-graphitizing carbons before and after heat treatment at temperatures in the range 2100–2600°C. It is found that these heat treatments can result in the formation of closed carbon nanoparticles, which are apparently fullerene-like in…
Alcaligenes latus has been known to produce poly(3-hydroxybutyrate) (PHB) in a growth-associated manner even under nutrient-sufficient conditions. However, the PHB content obtained by fed-batch culture was always low, at ca. 50%, which makes the recovery process inefficient. In this study, the effect of applying nitro…
Several novel fluorinated fluoresceins (Oregon Green dyes) were prepared by the reaction of fluororesorcinols with phthalic anhydride and its derivatives. A novel regiospecific synthesis of fluororesorcinols was key to the successful synthesis of these new fluorophores. (Polyfluoro)nitrobenzenes were reacted with 2 eq…
Colloidal dispersions of bimetallic nanoparticles composed of gold and palladium were prepared by a sonochemical method, in which Au(III) and Pd(II) ions in an aqueous solution of sodium tetrachloroaurate(III)dihydrate and sodium tetrachloropalladate(II) were reduced by ultrasound irradiation in the presence of sodium…
Biosynthesis of N-acetylneuraminic acid (Neu5Ac), a prominent component of glycoconjugates, is initiated by the action of UDP-N-acetylglucosamine 2-epimerase (UDP-GlcNAc 2-epimerase, EC 5.1. 3.14) and N-acetylmannosamine kinase (ManNAc kinase, EC 2.7.1.60). We demonstrate for the first time that the two activities are…
We present an experimental study of the frequency \ensuremath{\omega} dependence and volume fraction \ensuremath{\varphi} dependence of the complex shear modulus ${G}^{*}(\ensuremath{\omega},\ensuremath{\varphi})$ of monodisperse emulsions which have been concentrated by an osmotic pressure \ensuremath{\Pi}. At a give…
The molecular and crystal structure of the hydrated form of chitosan, which was obtained by deacetylation of chitin from crab tendon, was determined by the X-ray fiber diffraction method and the linked-atom least-squares method. The chitosan chains crystallize in an orthorhombic unit cell with dimensions a = 8.95(4),…
Large and good-optical-quality crystals of gadolinium and calcium oxoborate, Ca4GdO(BO3)3 (GdCOB) have been grown from a melt by the Czochralski pulling method. The crystal is absolutely insensitive to moisture. Linear- and quadratic nonlinear-optical properties of this new monoclinic biaxial borate crystal are report…
Quasiparticle gaps, self-energy corrections, exciton Coulomb energies, and optical gaps in Si quantum dots are calculated from first principles using a real-space pseudopotential method. The calculations are performed on hydrogen-passivated spherical Si clusters with diameters up to 27.2 \AA{} ( $\ensuremath{\sim}800\…
The mutual interaction between small oscillating cavitation bubbles ${(R}_{0}<10\ensuremath{\mu}\mathrm{m})$ in a strong acoustic field (${P}_{a}>1\mathrm{bar},$ $f=20\mathrm{kHz}$) is investigated numerically. We assume spherical symmetry and a coupling of the bubble oscillations. Our results show that the stre…