Découvert l'existence d'une forme de carbone méconnue : le carbone pyrolytique. C'est un empilement de couches de graphène moins régulier que dans le graphite *.
Cependant le graphite n'est formé que de minuscules cristaux comme ceux qui partent en poudre au bout de votre mine de crayon, alors qu'on est capable de produire des plaques de carbone pyrolytique de quelques centimètres de côté.
Les propriét&e........ Read more »
Kui Yao and colleagues from the A*STAR Institute of Materials Research and Engineering in Singapore have developed a battery-less photodetector that can harvest small quantities of detected light to generate enough energy to power a sensing signal transmission through a radio-frequency transmitter.... Read more »
Lai, S., Yao, K., & Chen, Y. (2013) A battery-less photo-detector enabled with simultaneous ferroelectric sensing and energy harnessing mechanism. Applied Physics Letters, 103(9), 92903. DOI: 10.1063/1.4819845
Shuze Zhu and Teng Li, of the Department of Mechanical Engineering at the University of Maryland, have found that they can make tiny squares of graphene fold into an origami box and store hydrogen in it.... Read more »
Zhu, S., & Li, T. (2014) Hydrogenation-Assisted Graphene Origami and Its Application in Programmable Molecular Mass Uptake, Storage, and Release. ACS Nano, 2147483647. DOI: 10.1021/nn500025t
University of Washington scientists have built the thinnest LED ever. It can be used as a source of light energy in electronics. The LED is based off of two-dimensional, flexible semiconductors, making it possible to stack or use in much smaller and more diverse applications than current technology allows.... Read more »
Ross, J., Klement, P., Jones, A., Ghimire, N., Yan, J., Mandrus, D., Taniguchi, T., Watanabe, K., Kitamura, K., Yao, W.... (2014) Electrically tunable excitonic light-emitting diodes based on monolayer WSe2 p–n junctions. Nature Nanotechnology. DOI: 10.1038/nnano.2014.26
I discuss a recent Science review about data regarding the cold tropical Pacific and its relationship to recent global temperature data.... Read more »
Clement, A., & DiNezio, P. (2014) The Tropical Pacific Ocean--Back in the Driver's Seat?. Science, 343(6174), 976-978. DOI: 10.1126/science.1248115
Researchers at the Vienna University of Technology have succeeded for the first time in creating a diode made of tungsten diselenide. Experiments show that this material may be used to create ultrathin flexible solar cells. Even flexible displays could become possible.... Read more »
Pospischil, A., Furchi, M., & Mueller, T. (2014) Solar-energy conversion and light emission in an atomic monolayer p–n diode. Nature Nanotechnology. DOI: 10.1038/nnano.2014.14
A mathematical proof of existence of a stochastic process involving fractional exponents seemed out of question after some mathematicians claimed this cannot not exist. This observation is strongly linked to the current definition and may undergo revision if nature does not agree with it. Stochastic process are very easy to simulate on a computer. Very […]... Read more »
Farina, A., Frasca, M., & Sedehi, M. (2013) Solving Schrödinger equation via Tartaglia/Pascal triangle: a possible link between stochastic processing and quantum mechanics. Signal, Image and Video Processing, 8(1), 27-37. DOI: 10.1007/s11760-013-0473-y
Marco Frasca, & Alfonso Farina. (2014) Numerical proof of existence of fractional Wiener processes. arXiv. arXiv: 1403.1075v1
Physicists at the Harvard School of Engineering and Applied Sciences (SEAS) envision a device that would harvest energy from Earth’s infrared emissions into outer space.... Read more »
Byrnes, S., Blanchard, R., & Capasso, F. (2014) Harvesting renewable energy from Earth's mid-infrared emissions. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1402036111
An international team of scientists led by physicists from the University of York has paved the way for a new class of magnetic materials and devices with improved performance and power efficiency.... Read more »
Evans, R., Ostler, T., Chantrell, R., Radu, I., & Rasing, T. (2014) Ultrafast thermally induced magnetic switching in synthetic ferrimagnets. Applied Physics Letters, 104(8), 82410. DOI: 10.1063/1.4867015
Ultraviolet light (UV) has not only harmful effects on molecules and biological tissue like human skin but it also can impair the performance of organic solar cells upon long-term exposure. Researchers of Kiel University and Helmholtz-Zentrum Geesthacht have now developed a so-called plasmonic metamaterial, which is compatible with solar technology and completely absorbs UV light—despite being only 20 nanometers thin.... Read more »
Hedayati, M., Zillohu, A., Strunskus, T., Faupel, F., & Elbahri, M. (2014) Plasmonic tunable metamaterial absorber as ultraviolet protection film. Applied Physics Letters, 104(4), 41103. DOI: 10.1063/1.4863202
Researchers from North Carolina State University have developed a “superabsorbing” design that may significantly improve the light absorption efficiency of thin film solar cells and drive down manufacturing costs.... Read more »
Researchers at TU Delft have come very close (99.8%) to the theoretical limit of light absorption enhancement (light trapping) in a broad light spectrum range. Their article on light management in ultra-thin silicon is accepted for publication in the journal ACS Photonics.... Read more »
Andrea Ingenito, Olindo Isabella, Miro Zeman. (2014) Experimental Demonstration of 4n2 Classical Absorption Limit in Nanotextured Ultrathin Solar Cells with Dielectric Omnidirectional Back Reflector. ACS Photonics. DOI: 10.1021/ph4001586
University of Colorado Boulder scientists have created a locally resonant nanophononic metamaterial for thermoelectric energy conversion, a finding that could one day lead to the development of improved solar panels, more energy-efficient cooling equipment, and even the creation of new devices that could turn the vast amounts of heat wasted at power plants into more electricity.... Read more »
Bruce L. Davis, Mahmoud I. Hussein. (2014) Nanophononic Metamaterial: Thermal Conductivity Reduction by Local Resonance. Physical Review Letters, 112(5). DOI: 10.1103/PhysRevLett.112.055505
Millennium problems represent a major challenge for physicists and mathematicians. So far, the only one that has been solved was the Poincaré conjecture (now a theorem) by Grisha Perelman. For people working in strong interactions and quantum chromodynamics, the most interesting of such problems is the Yang-Mills mass gap and existence problem. The solutions of […]... Read more »
Axel Maas. (2014) Some more details of minimal-Landau-gauge Yang-Mills propagators. arXiv. arXiv: 1402.5050v1
Axel Weber. (2012) Epsilon expansion for infrared Yang-Mills theory in Landau gauge. Phys. Rev. D , 125005. arXiv: 1112.1157v2
Axel Weber. (2012) The infrared fixed point of Landau gauge Yang-Mills theory. arXiv. arXiv: 1211.1473v1
Marco Frasca. (2009) Mapping a Massless Scalar Field Theory on a Yang-Mills Theory: Classical Case. Mod. Phys. Lett. A 24, 2425-2432 (2009). arXiv: 0903.2357v4
Marco Frasca. (2010) Mapping theorem and Green functions in Yang-Mills theory. PoS FacesQCD:039,2010. arXiv: 1011.3643v3
There are several open challenges that our society has to address in the near future: produce sufficient amounts of clean energy from renewable sources, design new technologies that enable a sustainable economic growth, address some relevant environmental issues like quality of air and water or waste recycling, improve our standard of life via more accurate diagnostic tools and new medical treatments, just to mention a few. Most of these challenges deal with the design, synthesis, characterizati........ Read more »
Gianfranco Pacchioni. (2014) Smart Materials from Nanotechnology for Global Challenges. Journal of Nanotechnology and Smart Materials, 1(1), 1-1. info:/1: 101
An electrode designed like a pomegranate — with silicon nanoparticles clustered like seeds in a tough carbon rind — overcomes several remaining obstacles to using silicon for a new generation of lithium-ion batteries, say its inventors at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory.... Read more »
Nian Liu, Zhenda Lu, Jie Zhao, Matthew T. McDowell, Hyun-Wook Lee, Wenting Zhao . (2014) A pomegranate-inspired nanoscale design for large-volume-change lithium battery anodes. Nature Nanotechnology. DOI: 10.1038/nnano.2014.6
Ignition—the process of releasing fusion energy equal to or greater than the amount of energy used to confine the fuel—has long been considered the “holy grail” of inertial confinement fusion science.... Read more »
O.A. Hurricane, D.A. Callahan, D. T. Casey, P.M. Celliers, C. Cerjan, E.L. Dewald, T.R. Dittrich, T. Döppner, D.E. Hinkel, L.F. Berzak Hopkins, J.L. Kline, S. Le Pape, T. Ma, A.G. MacPhee, J.L. Milovich, A. Pak, H.-S. Park, P.K. Patel, B.A. Remingt. (2014) Fuel gain exceeding unity in an inertially confined fusion implosion. Nature. DOI: 10.1038/nature13008
Researchers at the Helmholtz Center Berlin (HZB) have taken a leap forward towards a deeper understanding of light-induced degradation in thin film solar cells based on amorphous silicon.... Read more »
M. Fehr, A. Schnegg, B. Rech, O. Astakhov, F. Finger, R. Bittl, C. Teutloff, and K. Lips. (2014) Metastable Defect Formation at Microvoids Identified as a Source of Light-Induced Degradation in a−Si:H. Physical Review Letters, 112(1). DOI: 10.1103/PhysRevLett.112.066403
I noticed on the arXiv server this morning that a preprint has appeared with the 2013 update of the project, run by Michael Thoennessen of MSU, documenting the experimental discover of nuclides. Nuclides are the nuclear equivalent of chemical elements - the basic units of matter. Each element is characterised by the number of protons in the nucleus (or equivalently by the number of electrons orbiting a neutral atom of the element). They run from element #1 - Hydrogen, with one p........ Read more »
A paper just out in Nature Neuroscience proposes a new tool for neuroscientists who want to stimulate the brain – ultrasound. There are already a number of established ways of modulating human brain activity. As neuronal firing is essentially electrical, most of these methods rely on electricity – such as TDCS – or on magnetic […]The post Is Ultrasonic Brain Stimulation The Future? appeared first on Neuroskeptic.... Read more »
Legon W, Sato TF, Opitz A, Mueller J, Barbour A, Williams A, & Tyler WJ. (2014) Transcranial focused ultrasound modulates the activity of primary somatosensory cortex in humans. Nature neuroscience, 17(2), 322-9. PMID: 24413698
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