Department of Applied Chemistry and Chemical Engineering, Claude Bernard University (Lyon I): Current Research in Adhesion Science

This paper reviews the activity in adhesion science of the Department of Applied Chemistry and Chemical Engineering (CNRS, URA 417) of the University of Lyon, France. This work essentially concerns treatments and modifications of surfaces by various chemical, electrochemical and physical techniques-electropolymerization, plasma polymerization, sol-gel processes, phosphatation, etc. Examples of the characterization of these surfaces and that of bonded joints are shown. Emphasis is placed on the possibilities offered by the techniques developed in the laboratory (low-energy electron-induced X-ray spectrometry and the three-point flexure test).     

On LP-MUSIC

Studies the consistency properties of a method recently proposed for temporal or spatial frequency estimation from noisy data. The method in question is a MUSIC technique that makes use of a linear prediction algorithm to determine the signal subspace. It is shown that the signal subspace determined by the subject linear prediction-MUSIC (LP-MUSIC) algorithm can collapse in certain scenarios and. Hence, that the LP-MUSIC frequency estimates are not always consistent. The difficulties LP-MUSIC may encounter in some cases are illustrated by means of numerical examples     

Phase Relations and Properties of Phases in the TlInSe2–TlPrSe2 System

The phase diagram of the TlInSe₂–TlPrSe₂ system was mapped out using differential thermal analysis and x-ray diffraction data. The system was found to contain a partial solid-solution series (0–10 mol % TlPrSe₂) and a quaternary compound of composition Tl₂InPrSe₄. The electrical conductivity, Hall coefficient, and thermoelectric power of TlPrSe₂ and Tl₂InPrSe₄ were measured in the temperature range 300–1100 K. The charge carriers in these compounds were shown to be scattered mainly by longitudinal acoustic phonons.     

The effect of multipath on the detection of symbol-rate spectrallines by delay and multiply receivers

The effect of a secondary path signal on the detectability of the symbol rate spectral line of a binary phase-shift keyed (BPSK) signal by a delay and multiply receiver is investigated. The measure of detectability used is the rate line signal-to-noise ratio. The parameters that define the secondary path signal are initially modeled as deterministic quantities; the phase of the secondary path signal is then taken to be a random variable independent and uniform on (0, 2π). It is found that, with deterministic path parameters, the presence of a secondary path can seriously affect the detectability of BPSK rate lines. When the phase is taken to be uniform on (0, 2π) over the receiver observation time, then the delay and multiply receiver performs as if no multipath is present. In this case, a noncoherent power addition of the primary and secondary path signals occurs     

Improved-performance, InGaAs/InGaAsP (/spl lambda/=980 nm) asymmetric broad-waveguide diode lasers via waveguide-core doping

Doping the waveguide core (p=2/spl times/10/sup 17/ cm/sup -1/) in asymmetric-waveguide InGaAs/InGaAsP, two-quantum-well diode lasers (/spl lambda/=980 nm) raises the injection efficiency to 90% and decreases the threshold-current density, J/sub th/. For 2 mm long, 100 /spl mu/m wide stripe, uncoated chips J/sub th/ decreases from /spl sim/188 A/cm/sup 2/ to /spl sim/150 A/cm/sup 2/. High characteristic temperatures for J/sub th/ and the slope efficiency are obtained: T/sub 0/=215K and T/sub 1/=600K.