511 research outputs found
Light Emission in Silicon from Carbon Nanotubes
The use of optics in microelectronic circuits to overcome the limitation of
metallic interconnects is more and more considered as a viable solution. Among
future silicon compatible materials, carbon nanotubes are promising candidates
thanks to their ability to emit, modulate and detect light in the wavelength
range of silicon transparency. We report the first integration of carbon
nanotubes with silicon waveguides, successfully coupling their emission and
absorption properties. A complete study of this coupling between carbon
nanotubes and silicon waveguides was carried out, which led to the
demonstration of the temperature-independent emission from carbon nanotubes in
silicon at a wavelength of 1.3 {\mu}m. This represents the first milestone in
the development of photonics based on carbon nanotubes on silicon
Optical Gain in Carbon Nanotubes
Semiconducting single-wall carbon nanotubes (s-SWNTs) have proved to be
promising material for nanophotonics and optoelectronics. Due to the
possibility of tuning their direct band gap and controlling excitonic
recombinations in the near-infrared wavelength range, s-SWNT can be used as
efficient light emitters. We report the first experimental demonstration of
room temperature intrinsic optical gain as high as 190 cm-1 at a wavelength of
1.3 {\mu}m in a thin film doped with s-SWNT. These results constitute a
significant milestone toward the development of laser sources based on carbon
nanotubes for future high performance integrated circuits.Comment: 4 figure
Fast erasure decoder for a class of quantum LDPC codes
We propose a decoder for the correction of erasures with hypergraph product
codes, which form one of the most popular families of quantum LDPC codes. Our
numerical simulations show that this decoder provides a close approximation of
the maximum likelihood decoder that can be implemented in O(N^2) bit operations
where N is the length of the quantum code. A probabilistic version of this
decoder can be implemented in O(N^1.5) bit operations.Comment: 5 pages, 2 figure
Nonlinear Harmonic Analysis of a Blade Model Subjected to Large Geometrical Deflection and Internal Resonance
International audienceThis paper is devoted to the study of the nonlinear harmonic response of an industrial blade model subjected to large geometrical deflection. A reduction procedure is performed on the blade model using the linear normal modes of the structure. Geometrical nonlinear effects are taken into account by considering cubic and quadratic stiffnesses in the dynamical reduced model. Reduced nonlinear stiffness coefficients are computed with the STiffness Evaluation Procedure (STEP) and periodic solutions are sought using the Harmonic Balance Method (HBM) coupled to a pseudo-arclength continuation. Along with the harmonic response, a bifurcation analysis is performed to compute both turning and branching points. Specific attention is paid to the internal resonance phenomenon. 2 to 1 internal resonance occurred during the frequency response analysis close to the first and second modes of the reduced model. Mode coupling phenomena occurred during the harmonic analysis and secondary branches of solutions were obtained from branching point bifurcations
The Hijacking of the Bioeconomy
Unidad de excelencia MarÃa de Maeztu MdM-2015-0552Georgescu-Roegen used the term bioeconomy to refer to a radical ecological perspective on economics he developed in the 1970s and 1980s. In recent years, it has also become a buzzword used by public institutions to announce and describe a supposed current economic and ecological transition. We see in this use an attempt of semantic hijacking of the original term. To support this claim we analyze three different interpretations of the term bioeconomy, presenting each of them as narratives combining distinct visions of future economic development, technical trajectories and imaginaries associated with a particular relationship to nature. Finally, we discuss these narratives in relation to the endorsement they receive by different stakeholders
- …