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Wimereux, France

Zhang S.,East China Normal University | Zhang S.,Shanghai Normal University | Liu Q.,East China Normal University | Shen M.,East China Normal University | And 4 more authors.
Dalton Transactions | Year: 2012

To overcome the separation difficulty of the palladium-based homogeneous catalyst, the palladium complex can be anchored on various supports such as silica, polymers and nanoparticles. For the same purpose, we describe a general and facile method to immobilize palladium bis(phosphine) complexes on the basis of the technique widely used for metal-organic framework (MOF) synthesis, yielding a mesoporous coordination polymer palladium-CP1. Although palladium complexes are generally not stable enough to allow further manipulation, we succeeded in preparation of a palladium coordination polymer without by-product Pd clusters or nanoparticles. The fresh palladium-CP1 catalyst exhibits a yield close to 55% for tolane at room temperature and 24 h in Sonogashira coupling of iodobenzene and phenylacetylene, as compared with a yield of 89% for its homogeneous counterpart [Pd(PPh 3) 2Cl 2]. Furthermore, this catalyst is stable enough to be reused more than four times with no Pd and Zn leaching. Therefore this new immobilization method offers great promise for the produce of recyclable palladium heterogeneous catalysts with higher activity and higher thermal and chemical stability in the future. © 2012 The Royal Society of Chemistry. Source

Touati Y.,University Of Lille1
2011 IEEE International Conference on Robotics and Biomimetics, ROBIO 2011 | Year: 2011

This paper deals with robust fault detection and isolation using bond graph approach and linear filters. The bond graph tool is used to model the dynamic system and the uncertainties on the sensors and actuators. The same model is used to generate systematically the analytical redundancy relations and the thresholds. A specific form of digital linear filter is used to evaluate the residuals and to ameliorate the robustness and the detectability of the faults. the developed procedure is applied to experimental data of an electromechanical system which is a subsystem of a mobile robot named Robotino. © 2011 IEEE. Source

d'Haese R.,Ecole Nationale Superieure de Chimie de Lille | Pawlowski L.,Ecole Nationale Superieure de Chimie de Lille | Bigan M.,ProBioGEM | Jaworski R.,Ecole Nationale Superieure de Chimie de Lille | Martel M.,University Of Lille1
Surface and Coatings Technology | Year: 2010

Fine, hydroxyapatite (HA) powder, synthesized using calcium nitrate and diammonium nitrate was formulated with water and alcohol to obtain a suspension used to plasma spray coatings onto titanium substrates. The deposition process was optimized using statistical design of 2n experiments with two variables: spray distance and electric power input to arc plasma. The sprayed coatings were soaked in simulated body fluid (SBF) for the periods of 3, 7, 14, 28, and 60 days at controlled temperature of 37 °C. The reference intensity ratio (RIR) method basing onto X-ray diffraction (XRD) data was used to determine quantitatively the phase composition of as-sprayed and soaked deposits. Electron probe microanalysis (EPMA) enabled to make the profiles of calcium to phosphorus atomic ratio along a line though the coatings' cross sections. Raman spectroscopy of selected samples enabled to localize the different crystal phases in sprayed coatings. The coatings included some porosity and have two characteristic zones: (i) dense zone corresponding to the lamellas, observed usually in thermally sprayed coatings; (ii) sintered zone containing fine hydroxyapatite grains which correspond to the fine solids from the suspension which were agglomerated in the cold regions of plasma jet and sintered on the substrate. The soaking in SBF homogenizes the morphology of coatings. The sintered zone disappears and the pores get filled by the reprecipitated calcium phosphates. © 2009 Elsevier B.V. All rights reserved. Source

D'Este P.,Polytechnic University of Valencia | D'Este P.,University of Sussex | Iammarino S.,The London School of Economics and Political Science | Iammarino S.,University of Sussex | And 3 more authors.
Research Policy | Year: 2012

Innovating firms are likely to face several challenges and experience different types of barriers. In this paper we argue that it is necessary to distinguish between two kinds of barriers to innovation. The first corresponds to what we describe as revealed barriers and reflects the degree of difficulty of the innovation process and the learning experience consequent on the firm engaging in innovation activity. The second type of impediment, which we label deterring barriers, encompasses the obstacles that prevent firms from committing to innovation. We use data from the 4th UK Community Innovation Survey (CIS4) to investigate the relationship between firms' engagement in innovation and their assessment of the barriers to innovation. We show that the relationship is curvilinear in the case of costs and market barriers. These results have important implications for innovation policy and innovation management. © 2011 Elsevier B.V. Source

Bakli H.,University Of Lille1 | Haddadi K.,University Of Lille1 | Lasri T.,Lille University of Science and Technology
Conference Record - IEEE Instrumentation and Measurement Technology Conference | Year: 2013

An interferometric technique for scanning near-field microscopy applications is proposed. The method is based on the association of a vector network analyzer, an evanescent microwave coaxial probe and a precise interferometer built up with a power divider, a phase-shifter and an attenuator. Advantages such as simplicity of operation, broad frequency band capabilities and high measurement sensitivity are achieved. In particular, a scanning near-field microwave microscope is built and experiments related to the measurement sensitivity in the frequency range 2-6 GHz are demonstrated. © 2013 IEEE. Source

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