Subcritical crack growth and crack closure are analysed using the double-cleavage-drilled-compression method, in two calcium phosphate based glasses. The measurements of the crack velocity as a function of temperature, from ambient to 250°C, are reported for two different relative humidity levels. Studied glasses present unusual trends characterized by a non gradual shift of V-KI curves versus temperature. Moreover, when the load is released and crack closes, expulsion of a “liquid-like” phase is observed forming droplets along the crack path. These droplets are only formed at certain temperatures, but both under high and low water humidity. They evolve toward residues when temperature is decreased.

Silica ionogels were synthesized from tetramethoxysilane (T MOS ),methyltrimethoxysilane (MT MS ) and 1-ethyl- 2-methylimidazolium Acetate (EMI MAc: Ionic Liquid) in different proportions .The textural characterizations showed an effect of these concentrations on the corresponding aerogels: pore size distributions and effective surfaces. The structure of the aerogels was measured with a SAXS (Small- Angle XRay Scattering) apparatus and was typical of acid catalyzed aerogels. Conductivity voltage measurements, operated on the ionogels, were carried out using an electrical 4 wire-electrodes set up. The electrical voltage temporal response of the EMIMAc silica ionogel was modelled by a RLC series circuit which characteristics depended on the synthesis.

Silica gels were synthesized from TMOS and MTMS in different proportions changing the ionic liquid concentration. EMIMac have significant influence in the gelation processe. The textural characterizations showed an effect of these concentrations on the corresponding aerogels: pore size distributions and effectives surfaces. The structure of the aerogels was measured with a SAXS apparatus and was typical of acid catalyzed aerogels. Conductivity measurements, operated on the ionogels, were carried out using an original electrical 4 electrodes set up which allowed us to study the ionic conductivity at the pore scale. The results obtained showed that one can model the electrical temporal response of the EMIMAc silica ionogel with a RLC series circuit.

We report on Terahertz wireless communications and fast imaging experiments at 300 GHz, using nanometer-sized transistors as detectors. The physical mechanism of the detection is related to the overdamped plasma waves in the transistor channel.

Terahertz Detection of quantum cascade laser emission by plasma waves in Nano-transistors

First communication link using a 300-GHz source and a Si plasma-wave detector

The invention relates to a laser device for emitting waves in a frequency range belonging to the terahertz range, characterized in that it includes the following, in combination: a wave guide (1) extending longitudinally along an axis A-A'; a superconducting coil (4) arranged coaxially to the wave guide (1) and arranged at a first end (112) of the wave guide (1); a p-Ge p-doped germanium crystal (3) arranged inside the coil (4) such that the turns of the superconducting coil (4) at least partially surround said p-Ge crystal (3); a cooling means (7) containing a coolant, the superconducting coil (4) and the p-Ge crystal (3) being arranged in the cooling means (7), and the wave guide (1) partially extending outside the cooling means (7); and a means (13) for removing the coolant from the wave guide