Quantum Hall resistance standards from graphene grown by chemical vapour deposition on silicon carbide.

Replacing GaAs by graphene to realize more practical quantum Hall resistance standards (QHRS), accurate to within 10(-9) in relative value, but operating at lower magnetic fields than 10 T, is an ongoing goal in metrology. To date, the required accuracy has been reported, only few times, in graphene grown on SiC by Si sublimation, under higher magnetic fields. Here, we report on a graphene device grown by chemical vapour deposition on SiC, which demonstrates such accuracies of the Hall resistance from 10 T up to 19 T at 1.4 K. This is explained by a quantum Hall effect with low dissipation, resulting from strongly localized bulk states at the magnetic length scale, over a wide magnetic field range. Our results show that graphene-based QHRS can replace their GaAs counterparts by operating in as-convenient cryomagnetic conditions, but over an extended magnetic field range. They rely on a promising hybrid and scalable growth method and a fabrication process achieving low-electron-density devices.

Epitaxial graphene on cubic SiC(111)Si(111) substrate.

Epitaxial graphene films grown on silicon carbide (SiC) substrate by solid state graphitization is of great interest for electronic and optoelectronic applications. In this paper, we explore the properties of epitaxial graphene films on 3C-SiC(111)Si(111) substrate. X-ray photoelectron spectroscopy and scanning tunneling microscopy were extensively used to characterize the quality of the few-layer graphene (FLG) surface. The Raman spectroscopy studies were useful in confirming the graphitic composition and measuring the thickness of the FLG samples.

[Venous insufficiency and varicose disease. Sequelae of lower limb thrombosis. The role of crenotherapy]. / Insuffisance veineuse et maladie variqueuse. Séquelles de thrombose des membres inférieurs. Place de la crénothérapie.

The writers reminded that a consensus on Classification of veinous diseases, necessary to build up homogeneous samples, was being set up. Now, they are introducing a thermal nosology that is as useful. Next, the history of spas, the characteristics of Thermal Springs and thermal practices as well as their results are described. The writers present a standardization of the observation and control parameters of the therapeutic effects. The rigorous and scientific process was defined by an interdisciplinary scientific process was defined by an interdisciplinary scientific Council and it is based on the creation of a Computerized Laboratory of Research and a Thermal University. It has become an example in the field of thermalism. According to the results and the modern indications, the water cure has to be prescribed at an early stage. The practitioner must think about it and insert the water cure in the arsenal of veinous diseases. According to the hydrogeologists' estimates, BARBOTAN les thermes, the first European spa with about 22,000 patients is thought to possess enough water to allow from 40,000 to 60,000 people to be treated yearly. A thermal environment is the ideal place for an efficient vascular rehabilitation and functional re-education. In phlebology, more than one million people should benefit from a water cure yearly ... Only 70,000 follow this treatment. Everyone has to wonder about this situation, which, to those who do not benefit from a thermal cure in phlebology, is as astonishing as prejudicial.