Synthesis of novel mesoporous selenium-doped biochar with high-performance sodium diclofenac and reactive orange 16 dye removals

In this study, for the first time, a selenium-doped mesoporous biochar was prepared and efficiently employed for sodium diclofenac and reactive orange 16 dye adsorption. The characterization results indicated that selenium doping had a remarkable impact on Biochar-Se morphological and physicochemical structures. The efficacy of developed biochar samples on reactive orange 16 (RO-16) and diclofenac (DCF) removals was fully investigated. For both molecules (DCF and RO-16), Liu's equilibrium model offered the best fitness with maximum adsorption capacity values of 355 mg g−1 for DCF and 538 mg g−1 for RO-16 for Biochar-Se. Multiple mechanisms including pore filling, π-π interaction, and hydrogen bonding between the Biochar-Se and DCF/RO-16 molecules were involved in the adsorption process. Se-nanoparticles formed metal–oxygen bonds, which boosted the adsorption of DCF and RO-16 molecules. The current work offered a feasible approach for the development of Se-doped biochar adsorbent that is incredibly effective in treating wastewater

Realisation d'un filtre supraconducteur a 10 GHz

In this paper, we show the design, the realization and the characterization of a 10 GHz superconducting planar filter with a narrow band. At 77 K it compares favourably with a gold filter one and the results are in accordance with the simulation. The insertion loss of the superconducting filter are considered inferior to 0.2 dB at 77 K.Dans cet article, nous présentons la conception, la réalisation et la caractérisation d'un filtre planaire supraconducteur à bande étroite à 10 GHz. A 77 K ses performances sont comparables à celles d'un filtre analogue en or et en accord avec les prévisions théoriques. On estime que le filtre supraconducteur seul présente des pertes inférieures à 0,2 dB à 77 K

Rigid composite materials for anechoic chamber application

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Structure and morphological study of nanometer W and W3O thin films

International audienceIn this paper, the structure of nanometer tungsten thin films has been correlated to their surface morphology. Films have been deposited by RF-sputtering at a working pressure of 0.5 Pa and with a power density of 1.18 W/cm 2. Two phases with different morphology has been observed : W 3 O with a nanograins structure is present in the first step of the tungsten growth; and, when the thickness is increased, a pure tungsten Wolfram phase (W) with a lamellar structure appears. We demonstrate that W 3 O is related to a pollution of the target surface between two growth runs. We succeed to suppress this phase and to obtain pure tungsten Wolfram nanolayer, in order to realize [W/WO 3 ] n multilayer

Mesure de la conductivité complexe et de la résistance de surface de films supraconducteurs YBaCuO

We describe in this paper 2 non destructive measurement methods in microwaves (18-26 GHz) well-suited to the characterization of conducting and superconducting thin films. From the experimental values we show that it is possible to infer, without any hypothesis, the following parameters : $\sigma^*$, $R_{\rm s}$, $X_{\rm s}$ and $\lambda$ between 20 K and 300 K. Some examples are given with metallic and superconducting samples from various origins. At 22 GHz and below 75 K, YBaCuO films deposited on MgO have a surface resistance inferior to bulk copper one.Dans cet article nous décrivons 2 méthodes de mesure non destructives adaptées à la caractérisation en microondes (18-26 GHz) de films minces conducteurs et supraconducteurs. A partir des valeurs expérimentales nous montrons qu'il est possible d'en déduire les grandeurs caractéristiques à savoir $\sigma^*$, $R_{\rm s}$, $X_{\rm s}$ et $\lambda$ entre 20 K et 300 K. Nous donnons des exemples de caractérisation de films métalliques et supraconducteurs provenant de différentes origines. A 22 GHz, en dessous de 75 K, les films YBaCuO déposés sur MgO ont une résistance de surface inférieure à celle du cuivre massif

Electromagnetic absorber composite made of carbon fibers loaded epoxy foam for anechoic chamber application

International audienceThis paper presents a new electromagnetic absorbing material developed from carbon fibers loaded epoxy foam for an application in anechoic chamber. The composite was developed in order to replace the currently used pyramidal absorbers made of carbon particles loaded polyurethane foam. Epoxy-composites filled with different weight percentages (from 0 wt.% to 4 wt.%) and length (1 and 3 mm) of carbon fibers were achieved. After an optimization of the dispersion of carbon fibers in composite materials, the dielectric properties of the composites were measured using a coaxial-probe in the frequency range 4–18 GHz. Results have shown that the complex permittivity of the composites increases with the amount of charge and also with the length of the carbon fibers. Absorption performance of a prototype prepared with a low concentration (0.5 wt.%) of carbon fibers was measured in an anechoic chamber: it shows a mean gain of 10 dB compared to a commercial absorber. © 2017 Elsevier B.V

’Le pagus du Portois (France, Haute-Saône) entre l’Antiquité tardive et le haut Moyen Âge : études de sites et premières perspectives de recherche

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’Le pagus du Portois (France, Haute-Saône) entre l’Antiquité tardive et le haut Moyen Âge : études de sites et premières perspectives de recherche

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Mechanical properties of Al/Al2O3 nanolaminated films: correlation to microstructure

peer reviewedaudience: researcher, professional, studentWear resistance and the hardness of Al/Al2O3 nanolaminated films were investigated in this study. Monolithic films and multilayers were deposited on a silicon substrate with two different substrate temperatures: T-s= 25 degrees C and T-s= -90 degrees C. The period thickness of multilayers was lowering from 40 to 2 nm. From nanoindentation measurements, it appears that the hardness of multilayers has an intermediate value between those of metal (Al) and ceramic (Al2O3). The tribological test was conducted by the pin-on-disc method. The T-s=25 degrees C deposited multilayers, as well as single films, demonstrated poor wear resistance. The best wear resistance was obtained for multilayers deposited at the lowest substrate temperature (T-s= -90 degrees C). The results are ill good agreement with structural characterization. X-ray reflectometry demonstrated that the multilayer character of Al/Al2O3 is more pronounced for T-s= -90 degrees C. (C) 2000 Elsevier Science S.A. All rights reserved