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A Jullien

Publications and source records attributed to A Jullien.

6 recordsLinked to original sources
PubMed2006

Nonlinear mirror based on cross-polarized wave generation.

We present a new type of nonlinear mirror based on the generation of a cross-polarized wave through a nonresonant electronic third-order process. It is characterized by a reflection coefficient that depends on the input intensity. Its behavior results from the interference between the nonlinearly generated cross-polarized wave and a pi/2 phase-retarded wave. This setup has a lot of advantages: it does not require any phase matching, it is achromatic and suitable for femtosecond pulses, linear losses are easily adjustable, and the overall behavior is predictable. The device has been experimentally tested using BaF2 and YVO4 crystals.

Journal Article↗
PubMed2006

Comment on "Generation of 10(11) contrast 50 TW laser pulses".

We argue for a different physical interpretation of the results given in the recent Letter by Chvykov et al. [Opt. Lett.31, 1456 (2006)] in which a double nonlinear crystal scheme for cross-polarized wave generation is analyzed. We discuss the most important factors that explain the origin of the two-crystal scheme's increased efficiency, namely, the Kerr lensing effect and a Gouy phase shift. The position and orientation of the second crystal relative to the first one are unambiguously defined; related effects are illustrated by already published works on the subject.

Comment↗
PubMed2005

Leaching of heavy metals and polycyclic aromatic hydrocarbons from reclaimed asphalt pavement.

The work presented herein displays the results of a study addressing environmental concerns related to the possible leaching of pollutants from reclaimed asphalt pavement. Samples from an experimental site were tested in both static batch tests and column leaching tests. Selected heavy metals and polycyclic aromatic hydrocarbons (PAHs) were analysed in leachates. The results have allowed us to consider the leaching of pollutants to be rather weak for most of the parameters studied. Concentrations in solutions from batch leaching tests were generally below the EC limit values for drinking water. Pollutant concentrations from column experiments were higher in solutions as of the initial leaching stages, but then decreased rapidly and wound up at values below the detection limits. The factors influencing results proved to be the material grain size and the percolation water flow rate. Results from leaching experiments performed on core samples taken on two rebuilt road section pavements, containing 10% and 20% of reclaimed asphalt pavement, respectively, confirmed the results obtained from the batch and column experiments.

Conservation of Natural Resources↗
PubMed1998

Biomechanical properties of human os calcanei: relationships with bone density and fractal evaluation of bone microarchitecture.

The relationship between bone strength and bone mass is well established. The link between trabecular microarchitecture and biomechanical properties has been less extensively explored. To address this question, we have tested the mechanical behaviour of calcaneus bone samples and investigated the correlations between mechanical properties on the one hand, bone density and fractal analysis of microarchitecture on the other hand. Mechanical properties of 43 human os calcanei were determined by uniaxial compression testing of samples from tuber calcanei. Ash density, bulk density and dual energy X-ray absorptiometry of the samples were measured. Fractal analysis of the trabecular bone on calcaneus radiographs was performed by two estimators derived from the fractional Brownian motion model. The mechanical properties of human os calcis were found to correlate with age and density measurements. Fractal parameters derived from the bone texture analysis showed weaker but significant correlations with bone strength. Fractal analysis of texture could account in part for the variations of bone strength, but in this study cannot explain better than density the mechanical properties of trabecular bone. Nevertheless, it provides a non-invasive means of assessing molecular bone microarchitecture.

Aged↗