Meshless methods are new numerical simulation methods. Meshless methods are based on a simple set of nodes that has to be optimized to obtain a good convergence of the approximation. For these reasons, in this paper, we have developed a new procedure in order to generate the initial set of nodes. This approach does not rely on any existing meshing technique, such as Delaunay or advancing front. It is based on a map density of nodes and a regularization procedure.

A conical resonator using the acoustic near-field technique has been designed and developed. This resonator design is sensitive to the density and viscosity of liquids, as well as to the modification, without discontinuity, of the rheological properties of viscoelastic media. The experimental measurements agree with the results expected from the modelling of the resonator.

Investigation of the high voltage vacuum discharge characteristics − current derivative (di/dt), current, voltage, and soft as well as hard X-rays − versus time has been carried out. Recorded traces indicate pinching of the interelectrode discharge column two or three times during which the voltage increases to values as high as the initial voltage or even higher. X-ray radiation of high penetration power is emitted during these events. In addition, sausage instabilities have been observed during the pinch giving rise to extreme penetrating X-rays caused partly by the pinch voltage and partly by the sausage voltage. Visible electrode studies show the fact that the discharge is restricted to a narrow column. Finally, a theoretical treatment of the discharge mechanism that seems to be in good agreement with the experimental result is also presented.

A virtual NC − AFM machine has been built using the Matlab language. The virtual NC − AFM is identical to a real hybrid machine built with Digital Instruments and Omicron blocks. The role of every subset is described in detail, and special attention is paid to the parameters of the Automatic Gain Control (AGC) which controls the amplitude of the oscillations. The virtual machine is a powerful tool, that allows to solve, without any approximation, non linear coupled differential equations describing the physics of the tip-surface interaction. The machine is then used to study the frequency shift and damping signal in the approach-retract mode. Two types of situations are analyzed: the first one corresponds to the case where no dissipative force is introduced in the tip-surface interaction, the second one deals with dissipative forces. These last ones are here introduced by assuming a mechanical deformation of the surface under the tip. Interesting results are then obtained, in particular the fact that unstability may occur under some particular conditions. Most of the results obtained by simulation are then compared with those of analytical models already published in the literature.

This work describes a glow discharge lamp of the Grimm type. The lamp proved to be stable for periods up to about 2 hours. The intensity to background ratio of the Cu I 237.4 nm line from a brass target was found to be 200. Analysis of the experimental results showed that the discharge potential depends on the discharge current through a power law $(V=Ki^S)$. K and S are also power functions of the pressure P. Intensity was measured as a function of the lamp operating parameters (V, i, and P). Self-absorption was shown to be insignificant. The sputtering rate Q was found to vary with the lamp power W=Vi, Q=C Wm where C and m are constants.

We developed a very-low temperature scanning tunneling microscope (STM) working at 60 mK in a dilution refrigerator. It features both atomic resolution and micron-sized scanning range at low temperature. High-resolution spectroscopy of superconducting samples at a measured temperature of 60 mK are presented.

An instrumentation system for measuring wide frequency band complex permittivity of a sample submitted to a microwave irradiation has been optimized in order to allow macroscopic temperature measurements. The reaction of saponification of aromatic esters is studied using this instrumentation. We take interest in the behavior of the ionic conductivity phenomenon occurring in the reactive medium during microwave heating, and we compare it with the results obtained under classical heating. We show that the activation energy associated with ionic conductivity is lower when the reaction is performed under microwaves than when it is performed under classical heating. We thus deduce that microwaves act on the reaction advancement as a catalyst, and thus makes the reaction easier.