Self-assembled monolayers of C60-perylenetetracarboxylic diimide-C60 triad on indium tin oxide surface

Indium tin oxide (ITO) electrodes modified chemically with self-assembled monolayers (SAMs) of C₆₀-perylenetetracarboxylic diimide-C₆₀ triad have been designed for the first time to act as an efficient light-to-current converter in molecular devices. The monolayers were characterized using UV-Vis, X-ray photoelectron spectroscopy and atomic force microscopy. Photoelectrochemical measurement of the SAMs of C₆₀-Perylenetetracarboxylic diimide-C₆₀/ITO indicated prompt, steady, and reproducible photocurrent generation when irradiated by white light.     

Solvated structure of C60 nanowhiskers

This work characterizes the structure of C₆₀ nanowhiskers prepared by the liquid-liquid interfacial precipitation method in the C₆₀-saturated m-xylene and isopropyl alcohol system. Transmission electron microscopy and X-ray diffraction measurement show that the C₆₀ nanowhiskers had a hexagonal structure with cell dimensions a = 2.407 nm and c = 1.018 nm which is different from pristine C₆₀. The structure of the C₆₀ nanowhiskers in solution is different from that of the solvated structure reported for the C₆₀ nanotubes but similar to that reported for the C₆₀ bulk crystal solvated with m-xylene. X-ray diffraction analysis also showed a shift to fcc structure after solvent evaporation. The C₆₀ nanowhiskers prepared using toluene as solvent also showed a similar solvated structure, and a more rapid structural change into fcc upon drying was again observed.     

Nanoscale periodic and faceted structures formation on Si(1 0 0) by oblique angle oxygen ion sputtering

The dynamics of ripple topography on silicon surfaces generated by oxygen ion bombardment with increasing fluences have been investigated by atomic force microscopy (AFM). At the early stages of sputtering, periodic ripples with the wave vector parallel to ion beam direction are developed. At the late stages of sputtering, the ripple structure tends to break down and the surface becomes faceted. The growth rate of the ripples and the scaling exponents of the faceted surface have been determined. The results are discussed with reference to the Bradley–Harper theory and its nonlinear extension. Finally, the ripple wavelength is found to be a linear function of the bombarding energy.     

Cryo preparation of isolated rabbit pancreatic islets

A Flotronic silver membrane has been used as a vehicle to process, via freeze substitution, collagenase-derived rabbit pancreatic islets. The procedure provides: (1) a simple, inexpensive method for handling larger numbers of tightly clustered islet aggregates; (2) a metal surface for rapid heat transfer from specimen to cryogen resulting in an increased circumferential zone of fine structural preservation; (3) the elimination of possible artifacts associated with impact or rotation of biological specimens against a cooled, highly polished metal block; (4) superior preservation of structural components not usually observed by conventional modes of fixation; (5) retention of metabolic components which may subsequently be available for immunocytochemical or X-ray energy dispersive procedures.     

Axial resolution of confocal fluorescence microscopy

A simple analytic expression is given for the axial resolution of a confocal fluorescence microscope. The expression, which is based on the spatial frequency cut-off criterion of resolution, is valid for high aperture optics and arbitrary fluorescence wavelength.     

Assessment by Microscopy of the Coverage of Sludge Flocs by a Nano‐scale Surface Layer

Flocs are irregularly shaped suspended particles of complex structure and composition that occur naturally in aquatic systems. In water treatment facilities, the settling of flocs is extremely important. Transmission electron microscopy was used to quantify the formation of a nano‐scale surface layer on flocs from two laboratory bioreactors modelling a biological wastewater treatment facility. By comparing different floc populations, we demonstrated that flocs that settled quickly out of wastewater had a significant amount of this layer, whereas those with little nano‐scale surface layer had poor settling properties. This morphological feature of floc ultrastructure may permit engineering manipulations that promote floc settling.     

Elaboration of platinum-modified NiAl coatings by combustion synthesis: Simultaneous repairing and coating of Ni-based superalloys

The “SHS build-up process” under high gas pressure was previously reported in literature by the authors in order to repair damaged turbine blades. In this process, a brazing foil is inserted between a substrate of Ni-based superalloy and a reactant compact made of the 50 at % Ni-50 at % Al mixture. The heat released during the combustion synthesis of the Ni + Al compact gives rise to interdiffusion of the elements and consequently to joining at the interface. This study reports the effect of Pt addition to the Ni + Al compact on the SHS build-up process. Indeed, the turbine blades need to be coated after repairing to protect them against corrosion. The aim of this investigation was to show the feasibility of this process for simultaneous repairing and coating. Good results were obtained: the joint quality was found to be good and even with a content of 18 at % Pt, the Pt-aluminide coatings retained the β-NiAl structure without PtAl₂ precipitates. Moreover, these coatings are free of porosity and after 100 h of air treatment, a homogenous oxide layer free of porosity was formed.      

TiO2 thin films using organic liquid materials prepared by Hot-Wire CVD method

TiO₂ thin films prepared by Hot-Wire CVD method have been studied as a protecting material of transparent conducting oxide (TCO) against atomic hydrogen exposures for the fabrications of Si thin film solar cells. It was found that electrical conductivity of the films at room temperature reached a value of 0.4 S/cm. This value is 2-3 orders of magnitude higher than that of TiO₂ films prepared by RF magnetron sputtering and electron-beam evaporation methods in our previous works. The conductivity improvement seems to be partly due to the enlargement of TiO₂ crystallites.