A New Spin On Silicon Chips |
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Thursday, 17 May 2007 |
Today's computers rely on moving and storing electronic charge in semiconductors. They ignore another property of electrons known as spin. Manipulating an electron's spin, as opposed to manipulating its charge, is faster and takes much less energy. That means electronic circuits that store and process data using an electron's spin would make computers faster, smaller, and more energy efficient. While spintronic devices are easy to make using magnetic metals, to do so using semiconductors is challenging. So far, researchers have made spintronic devices from gallium arsenide, but making them from the far cheaper silicon has been difficult. Ian Appelbaum and his colleagues at the University of Delaware have now made the first silicon-based spintronic device, which they describe in this week's Nature....more  (0) Comments |
Determining Ripple Current Capability In Tantalum Hybrid Capacitors |
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Thursday, 17 May 2007 |
Tantalum Hybrid capacitors are finding use in applications ranging from radar phased array antennas and laser power supplies to computer and avionics power hold-up. Many of these capacitors suit military and high reliability needs. Hybrid capacitors have very high specific power compared to electrochemical supercapacitors and high specific energy compared to electrolytic capacitors.
A capacitor has internal resistance and its temperature rises when current is present at its terminals. The temperature rise is proportional to the square of the current and is directly related to the power dissipation. The degree of temperature rise is an important design consideration especially where large currents are necessary, such as in power supply filtering and dc pulse forming applications. This is true not only because a certain maximum temperature must not be exceeded but also because the life of a capacitor is strongly related to its operating temperature....more (0) Comments |
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Wheels:Actively Tuning In A Quieter Ride |
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Wednesday, 16 May 2007 |
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In the past, attempts to reduce the effects of noise and vibration in vehicles have been based on passive technology and the use of elastomeric springs for isolation. However, anti-vibration experts at Trelleborg, the German-based seal, damp, and protection specialist, has developed an innovative noise reduction system that uses active-force cancellation, sparking considerable interest among the world’s major automobile manufacturers. Active-force cancellation uses special actuators located near mount attachment points to generate waves of the same frequency and amplitude as those created by noise and vibrations. When transmitted 180° out of phase with the original disturbances, the waves cancel each other out. The actuators are driven in a closed-feed forward control loop, which means that multiple-order harmonic waves are cancelled even when engine speeds change very quickly....more (0) Comments |
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Inside AMD's Phenom And Opteron Quad-Core Architectures |
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Monday, 14 May 2007 |
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Analysis: There's a race to market as well as a design battle between AMD and Intel over which company has the best quad-core desktop and server processors. In lifting the lid on the new "10h" architecture, which will power its upcoming Phenom and Barcelona quad-core chips, AMD is throwing down the gauntlet to Intel in the battle for processor supremacy. To really understand where the quad-core competition stands, one must untangle the race to market from the debate over whose architecture is better. On the first score, Intel is clearly ahead. Intel already offers several quad-core desktop processors, as part of its Core 2 Quad and Core 2 Extreme families. On the server side, Intel currently ships no less than nine quad-core Xeon server chips....more (0) Comments |
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Last Updated ( Monday, 14 May 2007 )
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New 1/f Noise Discovery Promises To Improve Semiconductor-Based Sensors |
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Monday, 14 May 2007 |
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More sensitive sensors and detectors based on semiconductor electronics could result from new findings by researchers from the United States, Norway and Russia. Their research has yielded a decisive step in identifying the origin of the universal 1/f noise phenomenon. "One-over-f noise appears almost everywhere, from electronic devices and fatigue in materials to traffic on roads, the distribution of stars in galaxies, and DNA sequences," said Valerii Vinokour or Argonne's Materials Science Division. "Finding the common origin of one-over-f noise in its many forms is one of the grand challenges of materials physics. Our theory establishes the origin and lower limit to one-over-f noise in semiconductor electronics, helping to optimize detectors for commercial application."...more (0) Comments |
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System Clock Generators: PLL Synthesizer Vs. Crystal Oscillator Clock--A Comparison |
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Friday, 11 May 2007 |
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Paul Shockman of On Semiconductor answers the question, "Should the new circuit board design or redesign use several crystal oscillator (XO) modules or a phase locked loop (PLL) synthesizer as its system clock source?" Should the new circuit board design or redesign use several crystal oscillator (XO) modules or a phase locked loop (PLL) synthesizer as its system clock source? Whether a system clock is a control board within a rack of boards (e.g. multiple line cards), a single board router with switches, a server farm or a site area network, clocks will certainly be required. Could a PLL synthesizer source save board space and provide lower cost?...more (0) Comments |
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