General Electric

About: General Electric is a company organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Turbine & Signal. The organization has 76365 authors who have published 110557 publications receiving 1885108 citations. The organization is also known as: General Electric Company & GE.

Influence of the Electron Charge Distribution on Surface-Plasmon Dispersion

Abstract: The effects of the spatial variation of the electron density on the surface-plasmon dispersion relation are investigated. We show that measurements of that relation are a useful probe of the electron density in the surface region. Previous calculations on homogeneous materials have predicted a linear or quadratic dependence of the frequency on momentum parallel to the surface. We find that the usual surface-plasmon resonance frequency at first decreases with increasing momentum and then increases with further increases in momentum. This behavior agrees with the experimentally observed dispersion. Additional higher-frequency surface modes, similar to those observed in laboratory plasmas, are identified.

Nanomedicine, Nanotechnology in medicine

Abstract: Nanomedicine is a relatively new field of science and technology. It looks sometimes ill defined and interpretations of that term may vary, especially between Europe and the United States. By interacting with biological molecules, therefore at nanoscale, nanotechnology opens up a vast field of research and application. Interactions between artificial molecular assemblies or nanodevices and biomolecules can be understood both in the extracellular medium and inside the human cells. Operating at nanoscale allow to exploit physical properties different from those observed at microscale such as the volume/surface ratio. The investigated diagnostic applications can be considered for in vitro as well as for in vivo diagnosis. In vitro, the synthesized particles and manipulation or detection devices allow for the recognition, capture, and concentration of biomolecules. In vivo, the synthetic molecular assemblies are mainly designed as a contrast agent for imaging. A second area exhibiting a strong development is the "nanodrugs" where nanoparticles are designed for targeted drug delivery. The use of such carriers improves the drug biodistribution, targeting active molecules to diseased tissues while protecting healthy tissue. A third area of application is regenerative medicine where nanotechnology allows developing biocompatible materials which support growth of cells used in cell therapy. The application of nanotechnology to medicine raises new issues because of new uses they allow, for instance: Is the power of these new diagnostics manageable by the medical profession? What means treating a patient without any clinical signs? Nanomedicine can contribute to the development of a personalized medicine both for diagnosis and therapy. There exists in many countries existing regulatory frameworks addressing the basic rules of safety and effectiveness of nanotechnology based medicine, whether molecular assemblies or medical devices. But there is a need to clarify or to modify these regulations which mobilize many experts. France is a country where the medical development of nanotechnology is significant, like Germany, the United Kingdom or Spain, as regards the European Union. There is an active scientific community and industrial partners of all sizes, even if the technology transfer to industry is not as effective as in North America.

Experimental application of extremum seeking on an axial-flow compressor

Abstract: We show an application of the method of extremum seeking to the problem of maximizing the pressure rise in an axial-flow compressor. First we apply extremum seeking to the Moore-Greitzer model and design a feedback scheme actuated through a bleed valve which simultaneously stabilizes rotating stall and surge and steers the system towards the equilibrium with maximal pressure. Then we implement the scheme on a compressor rig in Murray's laboratory at the California Institute of Technology. We perform stabilization of rotating stall via air injection and implement extremum seeking through a slow bleed valve. The experiment demonstrates that extremum seeking ensures the maximization of the pressure rise starting on either side of the stall inception point. The experiment also resolves a concern that extremum seeking requires the use of periodic probing-the amplitude of probing needed to achieve convergence is far below the noise level of the compressor system (even outside rotating stall).

Drift and Conductivity Mobility in Silicon

Abstract: Drift mobility measurements have been made on eleven silicon single crystals ranging in resistivity from 19 to 180 ohm cm The drift mobility of electrons (${\ensuremath{\mu}}_{n}$) in the purest $p$-type crystals and of holes (${\ensuremath{\mu}}_{p}$) in the purest $n$-type crystals can be expressed by the formulas ${\ensuremath{\mu}}_{n}=(21\ifmmode\pm\else\textpm\fi{}02)\ifmmode\times\else\texttimes\fi{}{10}^{9}{T}^{\ensuremath{-}25\ifmmode\pm\else\textpm\fi{}01}$ and ${\ensuremath{\mu}}_{p}=(23\ifmmode\pm\else\textpm\fi{}01)\ifmmode\times\else\texttimes\fi{}{10}^{9}{T}^{\ensuremath{-}27\ifmmode\pm\else\textpm\fi{}01}$ between 160 and 400\ifmmode^\circ\else\textdegree\fi{}K At 300\ifmmode^\circ\else\textdegree\fi{}K ${\ensuremath{\mu}}_{n}$ and ${\ensuremath{\mu}}_{p}$ are 1350\ifmmode\pm\else\textpm\fi{}100 and 480\ifmmode\pm\else\textpm\fi{}15 ${\mathrm{cm}}^{2}$ (volt ${\mathrm{s}\mathrm{e}\mathrm{c})}^{\ensuremath{-}1}$, respectively The conductivity of some of these crystals was measured between 78 and 400\ifmmode^\circ\else\textdegree\fi{}K, and provides independent evidence for the temperature dependences of mobility quoted in the foregoingBelow 100\ifmmode^\circ\else\textdegree\fi{}K hole mobility in the $n$-type crystals decreases markedly, probably at least in part because of short-time trapping of the injected holes