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.

Properties of Gold-Doped Silicon

Abstract: Measurements of the temperature dependence of resistivity and Hall coefficient in gold-doped silicon show an acceptor level at 0.54 ev from the conduction band and a donor level at 0.35 ev from the valence band. These levels appear in equal concentrations within experimental error. The location of these levels is supported by photoconductivity measurements. A search was made for other levels associated with gold centers but none were found. The distribution coefficient for gold in silicon is 2.5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}5}$. Gold was introduced into the crystals by growing from a gold-doped melt and by diffusion into single crystals at high temperatures. The concentrations of gold observed in solution after saturation at various temperatures is consistent with that expected from the distribution coefficient. Gold acts as a recombination center detectable at concentrations as low as ${10}^{12}$ per ${\mathrm{cm}}^{3}$. Because the acceptor level is so close to the center of the forbidden band, it is possible to shift the Fermi level below the middle with large ratios of gold to residual donors. The acceptor level is measured in $p$-type silicon as 0.62 ev from the valence band, giving a value of band gap consistent with previous measurements by other methods.

The U-Interpreter

Abstract: The usual method of interpreting data flow graphs assumes a finite token capacity (usually one) on each arc. This unnecessarily limits the amount of parallelism that can be easily exploited in a program. The U-interpreter is a method for assigning labels to each computational activity as it is dynamically generated during program execution. The U-interpreter assigns and manipulates labels in a totally distributed manner, thus avoiding a sequential controller, which can be a bottleneck in the design of large multiple-processor machines.

Three-terminal adaptive nematic liquid-crystal lens device

Abstract: A 1 mm × 1 mm nematic liquid-crystal three-terminal device for optical beam forming (focusing/spoiling) is fabricated. A thin-film-resistor network on the device substrate layer is used to control the voltages on the 98 internal lens electrodes by use of only one variable external driver. By using a high-resistance thin-film layer of amorphous silicon under the 98-element parallel electrode structure layer, we generate a near-continuous index perturbation to form a cylindrical lens. The focal length of this lens is continuously variable from inifinity to 12 cm by use of a variable 1–4-V-peak 1-kHz square-wave external terminal control signal.

The Block Lanczos Method for Computing Eigenvalues

Abstract: In this paper, we describe a Block Lanczos method for computing a few of the least or greatest eigenvalues of a sparse symmetric matrix. A basic result of Kaniel and Paige describing the rate of convergence of Lanczos' method will be extended to the Block Lanczos method. The results of experiments conducted with this method will be presented and discussed.

The Science, Technology, and Implementation of TiAl Alloys in Commercial Aircraft Engines

Abstract: The present article will describe the science and technology of titanium aluminide (TiAl) alloys and the engineering development of TiAl for commercial aircraft engine applications. The GEnxTM engine is the first commercial aircraft engine that is flying titanium aluminide (alloy 4822) blades and it represents a major advance in propulsion efficiency, realizing a 20% reduction in fuel consumption, a 50% reduction in noise, and an 80% reduction in NOx emissions compared with prior engines in its class. The GEnxTM uses the latest materials and design processes to reduce weight, improve performance, and reduce maintenance costs. GE’s TiAl low-pressure turbine blade production status will be discussed along with the history of implementation. In 2006, GE began to explore near net shape casting as an alternative to the initial overstock conventional gravity casting plus machining approach. To date, more than 40,000 TiAl low-pressure turbine blades have been manufactured for the GEnxTM 1B (Boeing 787) and the GEnxTM 2B (Boeing 747-8) applications. The implementation of TiAl in other GE and non-GE engines will also be discussed.