Neutral atoms or condensed matter cannot emit EUV radiation. Ionization must take place first. EUV light can only be emitted by electrons which are bound to multicharged positive ions; for example, to remove an electron from a +3 charged carbon ion (three electrons already removed) requires about 65 eV.[1] Such electrons are more tightly bound than typical valence electrons. The existence of multicharged positive ions is only possible in a hot dense plasma. The Xe or Sn plasma sources for EUV lithography are either discharge-produced or laser-produced. Power output exceeding 100 W is a requirement for sufficient throughput. While state-of-the-art 193 nm excimer lasers offer intensities of 200 W/cm2,[2] lasers for producing EUV-generating plasmas need to be much more intense, on the order of 1011 W/cm2.[3] This indicates the enormous energy burden imposed by switching from generating 193 nm light (laser output approaching 100 W)[4] to generating EUV light (required laser or equivalent power source output exceeding 10 kW).[5]
A further characteristic of the plasma-based EUV sources under development is that they are not even partially coherent,[6] unlike the KrF and ArF excimer lasers used for current optical lithography. Further power reduction (energy loss) is expected in converting incoherent sources (emitting in all possible directions at many independent wavelengths) to partially coherent (emitting in a limited range of directions within a narrow band of wavelengths) sources by filtering (unwanted wavelengths and directions). On the other hand, coherent light poses a risk of monochromatic reflection interference and mismatch of multilayer reflectance bandwidth.[7]
As of 2008, the development tools had a throughput of 4 wafers per hour with a 120 W source.[8] For a 100 WPH requirement, therefore, a 3 kW source would be needed, which is not available in the foreseeable future. However, EUV photon count is determined by the number of electrons generated per photon which are collected by a photodiode; since this is essentially the highly variable secondary yield of the initial photoelectron, the dose measurement will be impacted by high variability. In fact, data by Gullikson et al.[9] indicated ~10% natural variation of the photocurrent responsivity. More recent data for silicon photodiodes remain consistent with this assessment.[10] Calibration of the EUV dosimeter is a nontrivial unsolved issue.[11] The secondary electron number variability is the well-known root cause of noise in avalanche photodiodes.[12]
Wednesday, December 1, 2010
Space Robotics
Robot is a system with a mechanical body, using computer as its brain. Integrating the sensors and actuators built into the mechanical body, the motions are realised with the computer software to execute the desired task. Robots are more flexible in terms of ability to perform new tasks or to carry out complex sequence of motion than other categories of automated manufacturing equipment. Today there is lot of interest in this field and a separate branch of technology 'robotics' has emerged. It is concerned with all problems of robot design, development and applications. The technology to substitute or subsidise the manned activities in space is called space robotics. Various applications of space robots are the inspection of a defective satellite, its repair, or the construction of a space station and supply goods to this station and its retrieval etc. With the over lap of knowledge of kinematics, dynamics and control and progress in fundamental technologies it is about to become possible to design and develop the advanced robotics systems. And this will throw open the doors to explore and experience the universe and bring countless changes for the better in the ways we live.
Areas Of Application
The space robot applications can be classified into the following four categories
1 In-orbit positioning and assembly: For deployment of satellite and for assembly of modules to satellite/space station.
2 Operation: For conducting experiments in space lab.
3 Maintenance: For removal and replacement of faulty modules/packages.
4 Resupply: For supply of equipment, materials for experimentation in space lab and for the resupply of fuel.
The following examples give specific applications under the above categories
Scientific experimentation:
Conduct experimentation in space labs that may include
" Metallurgical experiments which may be hazardous.
" Astronomical observations.
" Biological experiments.
Assist crew in space station assembly
" Assist in deployment and assembly out side the station.
" Assist crew inside the space station: Routine crew functions inside the space station and maintaining life support system.
Space servicing functions
" Refueling.
" Replacement of faulty modules.
" Assist jammed mechanism say a solar panel, antenna etc.
Space craft enhancements
" Replace payloads by an upgraded module.
" Attach extra modules in space.
Space tug
" Grab a satellite and effect orbital transfer.
" Efficient transfer of satellites from low earth orbit to geostationary orbit.
Areas Of Application
The space robot applications can be classified into the following four categories
1 In-orbit positioning and assembly: For deployment of satellite and for assembly of modules to satellite/space station.
2 Operation: For conducting experiments in space lab.
3 Maintenance: For removal and replacement of faulty modules/packages.
4 Resupply: For supply of equipment, materials for experimentation in space lab and for the resupply of fuel.
The following examples give specific applications under the above categories
Scientific experimentation:
Conduct experimentation in space labs that may include
" Metallurgical experiments which may be hazardous.
" Astronomical observations.
" Biological experiments.
Assist crew in space station assembly
" Assist in deployment and assembly out side the station.
" Assist crew inside the space station: Routine crew functions inside the space station and maintaining life support system.
Space servicing functions
" Refueling.
" Replacement of faulty modules.
" Assist jammed mechanism say a solar panel, antenna etc.
Space craft enhancements
" Replace payloads by an upgraded module.
" Attach extra modules in space.
Space tug
" Grab a satellite and effect orbital transfer.
" Efficient transfer of satellites from low earth orbit to geostationary orbit.
STEALTH FIGHTER
tealth means 'low observable'. The very basic idea of Stealth Technology in the military is to 'blend' in with the background. The quest for a stealthy plane actually began more than 50 years ago during World War II when RADAR was first used as an early warning system against fleets of bombers. As a result of that quest, the Stealth Technology evolved. Stealth Technology is used in the construction of mobile military systems such as aircrafts and ships to significantly reduce their detection by enemy, primarily by an enemy RADAR. The way most airplane identification works is by constantly bombarding airspace with a RADAR signal.
When a plane flies into the path of the RADAR, a signal bounces back to a sensor that determines the size and location of the plane. Other methods focus on measuring acoustic (sound) disturbances, visual contact, and infrared (heat) signatures. Stealth technologies work by reducing or eliminating these telltale signals. Panels on planes are angled so that radar is scattered and no signal returns. Planes are also covered in a layer of absorbent materials that reduce any other signature the plane might leave. Shape also has a lot to do with the `invisibility' of stealth planes. Extreme aerodynamics keeps air turbulence to a minimum and cut down on flying noise. Special low-noise engines are contained inside the body of the plane. Hot fumes are then capable of being mixed with cool air before leaving the plane. This fools heat sensors on the ground. This also keeps heat seeking missiles from getting any sort of a lock on their targets.
Stealth properties give it the unique ability to penetrate an enemy's most sophisticated defenses and threaten its most valued and heavily defended targets. At a cost of $2 billion each, stealth bombers are not yet available worldwide, but military forces around the world will soon begin to attempt to mimic some of the key features of stealth planes, making the skies much more dangerous.
HISTORY OF STEALTH AIRCRAFT
With the increasing use of early warning detection devices such as radar by militaries around the world in the 1930's the United States began to research and develop aircraft that would be undetectable to radar detection systems. The first documented stealth prototype was built out of two layers of plywood glued together with a core of glue and sawdust. This prototype's surface was coated with charcoal to absorb radar signals from being reflected back to the source, which is how radar detection systems detect items in the air.
Jack Northrop built a flying wing in the 1940's. His plane was the first wave of stealth aircraft that actually flew. The aircraft proved to be highly unstable and hard to fly due to design flaws. The United States initially orders 170 of these aircraft from Northrop but cancelled the order after finding that the plane had stability Flaws. Then in 1964, SR-71 the first Stealth airplane launched. It is well known as 'black bird'. It is a jet black bomber with slanted surfaces. This aircraft was built to fly high and fast to be able to bypass radar by its altitude and speed.
HOW DOES STEALTH TECHNOLOGY WORK?
The idea is for the radar antenna to send out a burst of radio energy, which is then reflected back by any object it happens to encounter. The radar antenna measures the time it takes for the reflection to arrive, and with that information can tell how far away the object is. The metal body of an airplane is very good at reflecting radar signals, and this makes it easy to find and track airplanes with radar equipment.
The goal of stealth technology is to make an airplane invisible to radar. There are two different ways to create invisibility: The airplane can be shaped so that any radar signals it reflects are reflected away from the radar equipment. The airplane can be covered in materials that absorb radar signals.
When a plane flies into the path of the RADAR, a signal bounces back to a sensor that determines the size and location of the plane. Other methods focus on measuring acoustic (sound) disturbances, visual contact, and infrared (heat) signatures. Stealth technologies work by reducing or eliminating these telltale signals. Panels on planes are angled so that radar is scattered and no signal returns. Planes are also covered in a layer of absorbent materials that reduce any other signature the plane might leave. Shape also has a lot to do with the `invisibility' of stealth planes. Extreme aerodynamics keeps air turbulence to a minimum and cut down on flying noise. Special low-noise engines are contained inside the body of the plane. Hot fumes are then capable of being mixed with cool air before leaving the plane. This fools heat sensors on the ground. This also keeps heat seeking missiles from getting any sort of a lock on their targets.
Stealth properties give it the unique ability to penetrate an enemy's most sophisticated defenses and threaten its most valued and heavily defended targets. At a cost of $2 billion each, stealth bombers are not yet available worldwide, but military forces around the world will soon begin to attempt to mimic some of the key features of stealth planes, making the skies much more dangerous.
HISTORY OF STEALTH AIRCRAFT
With the increasing use of early warning detection devices such as radar by militaries around the world in the 1930's the United States began to research and develop aircraft that would be undetectable to radar detection systems. The first documented stealth prototype was built out of two layers of plywood glued together with a core of glue and sawdust. This prototype's surface was coated with charcoal to absorb radar signals from being reflected back to the source, which is how radar detection systems detect items in the air.
Jack Northrop built a flying wing in the 1940's. His plane was the first wave of stealth aircraft that actually flew. The aircraft proved to be highly unstable and hard to fly due to design flaws. The United States initially orders 170 of these aircraft from Northrop but cancelled the order after finding that the plane had stability Flaws. Then in 1964, SR-71 the first Stealth airplane launched. It is well known as 'black bird'. It is a jet black bomber with slanted surfaces. This aircraft was built to fly high and fast to be able to bypass radar by its altitude and speed.
HOW DOES STEALTH TECHNOLOGY WORK?
The idea is for the radar antenna to send out a burst of radio energy, which is then reflected back by any object it happens to encounter. The radar antenna measures the time it takes for the reflection to arrive, and with that information can tell how far away the object is. The metal body of an airplane is very good at reflecting radar signals, and this makes it easy to find and track airplanes with radar equipment.
The goal of stealth technology is to make an airplane invisible to radar. There are two different ways to create invisibility: The airplane can be shaped so that any radar signals it reflects are reflected away from the radar equipment. The airplane can be covered in materials that absorb radar signals.
Optical Satellite Communication
The European Space Agency (ESA) has programmes underway to place Satellites carrying optical terminals in GEO orbit within the next decade. The first is the ARTEMIS technology demonstration satellite which carries both microwave and SILEX (Semiconductor Laser Intro satellite Link Experiment) optical interorbit communications terminal. SILEX employs direct detection and GaAIAs diode laser technology; the optical antenna is a 25cm diameter reflecting telescope.
The SILEX GEO terminal is capable of receiving data modulated on to an incoming laser beam at a bit rate of 50 Mbps and is equipped with a high power beacon for initial link acquisition together with a low divergence (and unmodulated) beam which is tracked by the communicating partner. ARTEMIS will be followed by the operational European data relay system (EDRS) which is planned to have data relay Satellites (DRS). These will also carry SILEX optical data relay terminals.
Once these elements of Europe's space Infrastructure are in place, these will be a need for optical communications terminals on LEO satellites which are capable of transmitting data to the GEO terminals. A wide range of LEO space craft is expected to fly within the next decade including earth observation and science, manned and military reconnaissance system.
The LEO terminal is referred to as a user terminal since it enables real time transfer of LEO instrument data back to the ground to a user access to the DRS s LEO instruments generate data over a range of bit rates extending of Mbps depending upon the function of the instrument. A significant proportion have data rates falling in the region around and below 2 Mbps. and the data would normally be transmitted via an S-brand microwave IOL
ESA initiated a development programme in 1992 for LEO optical IOL terminal targeted at the segment of the user community. This is known as SMALL OPTICAL USER TERMINALS (SOUT) with features of low mass, small size and compatibility with SILEX. The programme is in two phases. Phase I was to produce a terminal flight configuration and perform detailed subsystem design and modelling. Phase 2 which started in september 1993 is to build an elegant bread board of the complete terminal.
The SILEX GEO terminal is capable of receiving data modulated on to an incoming laser beam at a bit rate of 50 Mbps and is equipped with a high power beacon for initial link acquisition together with a low divergence (and unmodulated) beam which is tracked by the communicating partner. ARTEMIS will be followed by the operational European data relay system (EDRS) which is planned to have data relay Satellites (DRS). These will also carry SILEX optical data relay terminals.
Once these elements of Europe's space Infrastructure are in place, these will be a need for optical communications terminals on LEO satellites which are capable of transmitting data to the GEO terminals. A wide range of LEO space craft is expected to fly within the next decade including earth observation and science, manned and military reconnaissance system.
The LEO terminal is referred to as a user terminal since it enables real time transfer of LEO instrument data back to the ground to a user access to the DRS s LEO instruments generate data over a range of bit rates extending of Mbps depending upon the function of the instrument. A significant proportion have data rates falling in the region around and below 2 Mbps. and the data would normally be transmitted via an S-brand microwave IOL
ESA initiated a development programme in 1992 for LEO optical IOL terminal targeted at the segment of the user community. This is known as SMALL OPTICAL USER TERMINALS (SOUT) with features of low mass, small size and compatibility with SILEX. The programme is in two phases. Phase I was to produce a terminal flight configuration and perform detailed subsystem design and modelling. Phase 2 which started in september 1993 is to build an elegant bread board of the complete terminal.
Optical Satellite Communication
The European Space Agency (ESA) has programmes underway to place Satellites carrying optical terminals in GEO orbit within the next decade. The first is the ARTEMIS technology demonstration satellite which carries both microwave and SILEX (Semiconductor Laser Intro satellite Link Experiment) optical interorbit communications terminal. SILEX employs direct detection and GaAIAs diode laser technology; the optical antenna is a 25cm diameter reflecting telescope.
The SILEX GEO terminal is capable of receiving data modulated on to an incoming laser beam at a bit rate of 50 Mbps and is equipped with a high power beacon for initial link acquisition together with a low divergence (and unmodulated) beam which is tracked by the communicating partner. ARTEMIS will be followed by the operational European data relay system (EDRS) which is planned to have data relay Satellites (DRS). These will also carry SILEX optical data relay terminals.
Once these elements of Europe's space Infrastructure are in place, these will be a need for optical communications terminals on LEO satellites which are capable of transmitting data to the GEO terminals. A wide range of LEO space craft is expected to fly within the next decade including earth observation and science, manned and military reconnaissance system.
The LEO terminal is referred to as a user terminal since it enables real time transfer of LEO instrument data back to the ground to a user access to the DRS s LEO instruments generate data over a range of bit rates extending of Mbps depending upon the function of the instrument. A significant proportion have data rates falling in the region around and below 2 Mbps. and the data would normally be transmitted via an S-brand microwave IOL
ESA initiated a development programme in 1992 for LEO optical IOL terminal targeted at the segment of the user community. This is known as SMALL OPTICAL USER TERMINALS (SOUT) with features of low mass, small size and compatibility with SILEX. The programme is in two phases. Phase I was to produce a terminal flight configuration and perform detailed subsystem design and modelling. Phase 2 which started in september 1993 is to build an elegant bread board of the complete terminal.
The SILEX GEO terminal is capable of receiving data modulated on to an incoming laser beam at a bit rate of 50 Mbps and is equipped with a high power beacon for initial link acquisition together with a low divergence (and unmodulated) beam which is tracked by the communicating partner. ARTEMIS will be followed by the operational European data relay system (EDRS) which is planned to have data relay Satellites (DRS). These will also carry SILEX optical data relay terminals.
Once these elements of Europe's space Infrastructure are in place, these will be a need for optical communications terminals on LEO satellites which are capable of transmitting data to the GEO terminals. A wide range of LEO space craft is expected to fly within the next decade including earth observation and science, manned and military reconnaissance system.
The LEO terminal is referred to as a user terminal since it enables real time transfer of LEO instrument data back to the ground to a user access to the DRS s LEO instruments generate data over a range of bit rates extending of Mbps depending upon the function of the instrument. A significant proportion have data rates falling in the region around and below 2 Mbps. and the data would normally be transmitted via an S-brand microwave IOL
ESA initiated a development programme in 1992 for LEO optical IOL terminal targeted at the segment of the user community. This is known as SMALL OPTICAL USER TERMINALS (SOUT) with features of low mass, small size and compatibility with SILEX. The programme is in two phases. Phase I was to produce a terminal flight configuration and perform detailed subsystem design and modelling. Phase 2 which started in september 1993 is to build an elegant bread board of the complete terminal.
VISNAV
The VISNAV system uses a Position Sensitive Diode (PSD) sensor for 6 DOF estimation. Output current from the PSD sensor determines the azimuth and elevation of the light source with respect to the sensor. By having four or more light source called beacons in the target frame at known positions the six degree of freedom data associated with the sensor is calculated.
The beacon channel separation and demodulation are done on a fixed point digital signal processor (DSP) Texas Instruments TMS320C55x [2] using digital down conversion, synchronous detection and multirate signal processing techniques. The demodulated sensor currents due to each beacon are communicated to a floating point DSP Texas Instruments TMS320VC33 [2] for subsequent navigation solution by the use of colinearity equations.
Among other competitive systems [3] a differential global positioning system (GPS) is limited to midrange accuracies, lower bandwidth, and requires complex infrastructures. The sensor systems based on differential GPS are also limited by geometric dilution of precision, multipath errors, receiver errors, etc.These limitations can be overcome by using the DSP embedded VISNAV system
FACTORS AFECTING MEASUREMENT
There is likely to be a large amount of ambient light at short wavelength and low carrier frequencies due to perhaps the sun, its reflections, incandescent or discharge tube lights, LCD and cathode ray tube displays etc. In many cases this ambient energy would swap a relatively small beacon signal and the PSD centroid data would mostly correspond to this unwanted background light.
In order to avoid this problem by modulating the beacon controller current by a sinusoidal carrier of high frequency. The resulting PSD signal currents then vary sinsuoidally at approximately the same frequency and have to be demodulated to recover the actual current proportional to the beacon light centroid. This modulation or demodulation scheme leads high degree of insensitivity to variations in ambient light and it is a key to make the PSD sensing approach practical.
The beacon channel separation and demodulation are done on a fixed point digital signal processor (DSP) Texas Instruments TMS320C55x [2] using digital down conversion, synchronous detection and multirate signal processing techniques. The demodulated sensor currents due to each beacon are communicated to a floating point DSP Texas Instruments TMS320VC33 [2] for subsequent navigation solution by the use of colinearity equations.
Among other competitive systems [3] a differential global positioning system (GPS) is limited to midrange accuracies, lower bandwidth, and requires complex infrastructures. The sensor systems based on differential GPS are also limited by geometric dilution of precision, multipath errors, receiver errors, etc.These limitations can be overcome by using the DSP embedded VISNAV system
FACTORS AFECTING MEASUREMENT
There is likely to be a large amount of ambient light at short wavelength and low carrier frequencies due to perhaps the sun, its reflections, incandescent or discharge tube lights, LCD and cathode ray tube displays etc. In many cases this ambient energy would swap a relatively small beacon signal and the PSD centroid data would mostly correspond to this unwanted background light.
In order to avoid this problem by modulating the beacon controller current by a sinusoidal carrier of high frequency. The resulting PSD signal currents then vary sinsuoidally at approximately the same frequency and have to be demodulated to recover the actual current proportional to the beacon light centroid. This modulation or demodulation scheme leads high degree of insensitivity to variations in ambient light and it is a key to make the PSD sensing approach practical.
Friday, October 29, 2010
Light Trees
Today, there is a general consensus that, in the near future, wide area networks
(WAN)(such as, a nation wide backbone network) will be based on Wavelength
Division Multiplexed (WDM) optical networks. One of the main advantages of a WDM
WAN over other optical technologies, such as, Time Division Multiplexed (TDM)
optical networks, is that it allows us to exploit the enormous bandwidth of an optical
fiber (up to 50 terabits bits per second) with requiring electronic devices, which operate
at extremely high speeds.
(WAN)(such as, a nation wide backbone network) will be based on Wavelength
Division Multiplexed (WDM) optical networks. One of the main advantages of a WDM
WAN over other optical technologies, such as, Time Division Multiplexed (TDM)
optical networks, is that it allows us to exploit the enormous bandwidth of an optical
fiber (up to 50 terabits bits per second) with requiring electronic devices, which operate
at extremely high speeds.
Boiler Instrumentation and Controls
Instrumentation and controls in a boiler plant encompass an
enormous range of equipment from simple industrial plant to the complex
in the large utility station.
The boiler control system is the means by which the balance of
energy & mass into and out of the boiler are achieved. Inputs are fuel,
combustion air, atomizing air or steam &feed water. Of these, fuel is the
major energy input. Combustion air is the major mass input, outputs are
steam, flue gas, blowdown, radiation & soot blowing.
enormous range of equipment from simple industrial plant to the complex
in the large utility station.
The boiler control system is the means by which the balance of
energy & mass into and out of the boiler are achieved. Inputs are fuel,
combustion air, atomizing air or steam &feed water. Of these, fuel is the
major energy input. Combustion air is the major mass input, outputs are
steam, flue gas, blowdown, radiation & soot blowing.
LED Wireless
Billions of visible LEDs are produced each year, and
the emergence of high brightness AlGaAs and AlInGaP devices
has given rise to many new markets. The surprising growth of
activity in, relatively old, LED technology has been spurred by
the introduction of AlInGaP devices. Recently developed
AlGaInN materials have led to the improvements in the
performance of bluish-green LEDs, which have luminous
efficacy peaks much higher than those for incandescent lamps.
This advancement has led to the production of large-area fullcolor
outdoors LED displays with diverse industrial
applications.
The novel idea of this article is to modulate light
waves from visible LEDs for communication purposes. This
concurrent use of visible LEDs for simultaneous signaling and
communication, called iLight, leads to many new and interesting
applications and is based on the idea of fast switching of LEDs
and the modulation visible-light waves for free-space
communications. The feasibility of such approach has been
examined and hardware has been implemented with
experimental results. The implementation of an optical link has
been carried out using an LED traffic-signal head as atransmitter. The LED traffic light can be used for either audio
or data transmission.
Audio messages can be sent using the LED
transmitter, and the receiver located at a distance around 20 m
away can play back the messages with the speaker. Another
prototype that resembles a circular speed-limit sign with a 2-ft
diameter was built. The audio signal can be received in open air
over a distance of 59.3 m or 194.5 ft. For data transmission,
digital data can be sent using the same LED transmitter, and the
experiments were setup to send a speed limit or location ID
information.
The work reported in this article differs from the use
of infrared (IR) radiation as a medium for short-range wireless
communications. Currently, IR links and local-area networks
available. IR transceivers for use as IR data links are widely
available in the markets. Some systems are comprised of IR
transmitters that convey speech messages to small receivers
carried by persons with severe visual impairments. The Talking
Signs system is one such IR remote signage system developed at
the Smith-Kettlewell Rehabilitation Engineering Research
center. It can provide a repeating, directionally selective voice
message that originates at a sign. However, there has been very
little work on the use of visible light as a communication
medium.
the emergence of high brightness AlGaAs and AlInGaP devices
has given rise to many new markets. The surprising growth of
activity in, relatively old, LED technology has been spurred by
the introduction of AlInGaP devices. Recently developed
AlGaInN materials have led to the improvements in the
performance of bluish-green LEDs, which have luminous
efficacy peaks much higher than those for incandescent lamps.
This advancement has led to the production of large-area fullcolor
outdoors LED displays with diverse industrial
applications.
The novel idea of this article is to modulate light
waves from visible LEDs for communication purposes. This
concurrent use of visible LEDs for simultaneous signaling and
communication, called iLight, leads to many new and interesting
applications and is based on the idea of fast switching of LEDs
and the modulation visible-light waves for free-space
communications. The feasibility of such approach has been
examined and hardware has been implemented with
experimental results. The implementation of an optical link has
been carried out using an LED traffic-signal head as atransmitter. The LED traffic light can be used for either audio
or data transmission.
Audio messages can be sent using the LED
transmitter, and the receiver located at a distance around 20 m
away can play back the messages with the speaker. Another
prototype that resembles a circular speed-limit sign with a 2-ft
diameter was built. The audio signal can be received in open air
over a distance of 59.3 m or 194.5 ft. For data transmission,
digital data can be sent using the same LED transmitter, and the
experiments were setup to send a speed limit or location ID
information.
The work reported in this article differs from the use
of infrared (IR) radiation as a medium for short-range wireless
communications. Currently, IR links and local-area networks
available. IR transceivers for use as IR data links are widely
available in the markets. Some systems are comprised of IR
transmitters that convey speech messages to small receivers
carried by persons with severe visual impairments. The Talking
Signs system is one such IR remote signage system developed at
the Smith-Kettlewell Rehabilitation Engineering Research
center. It can provide a repeating, directionally selective voice
message that originates at a sign. However, there has been very
little work on the use of visible light as a communication
medium.
Intel Nehalem
Nehalem (pronounced /nəˈheɪləm/[1]) is the codename for an Intel processor microarchitecture,[2] successor to the Core microarchitecture. The first processor released with the Nehalem architecture is the desktop Core i7,[3] which was released on November 15, 2008 in Tokyo and November 17, 2008 in the USA.[4]
Initial Nehalem processors use the same 45 nm manufacturing methods as Penryn. A working system with two Nehalem processors was shown at Intel Developer Forum Fall 2007,[5] and a large number of Nehalem systems were shown at Computex in June 2008.
The microarchitecture is named after the Nehalem Native American nation in Oregon.[citation needed] The code name itself had been seen on the end of several roadmaps starting in 2000. At that stage it was supposed to be the latest evolution of the NetBurst microarchitecture. Since the abandonment of NetBurst, the codename has been recycled and refers to a completely different project, although Nehalem still has some things in common with NetBurst. Nehalem-based microprocessors utilize higher clock speeds and are more energy-efficient than Penryn microprocessors. Hyper-Threading is reintroduced along with an L3 Cache missing from most Core-based microprocessors.
The first computer to use Nehalem-based Xeon processors was the Apple Mac Pro workstation announced on March 3, 2009.[6] Nehalem-based Xeon EX processors for larger servers are expected in Q4 2009.[7] Mobile Nehalem-based processors are planned to follow in late 2009 or early 2010.
Technology
Various sources have stated the specifications of processors in the Nehalem family:
• Two, four, six, or eight cores
o 731 million transistors for the quad core variant
• 45 nm manufacturing process
• Integrated memory controller supporting two or three memory channels of DDR3 SDRAM or four FB-DIMM channels
• Integrated graphics processor (IGP) located off-die, but in the same CPU package[8]
• A new point-to-point processor interconnect, the Intel QuickPath Interconnect, in high-end models, replacing the legacy front side bus
• Integration of PCI Express and Direct Media Interface into the processor in mid-range models, replacing the northbridge
• Simultaneous multithreading (SMT) by multiple cores which enables two threads per core. Intel calls this hyper-threading. Simultaneous multithreading has not been present on a consumer desktop Intel processor since 2006 with the Pentium 4 and Pentium XE. Intel reintroduced SMT with their Atom Architecture.
• Native (monolithic, i.e. all processor cores on a single die) quad- and octa-core processors[9]
• The following caches:
o 32 KB L1 instruction and 32 KB L1 data cache per core
o 256 KB L2 cache per core
o 4–8 MB L3 cache shared by all cores
• 33% more in-flight micro-ops than Conroe[10]
• Second-level branch predictor and second-level translation lookaside buffer[10]
• Modular blocks of components such as cores that can be added and subtracted for varying market segments
Initial Nehalem processors use the same 45 nm manufacturing methods as Penryn. A working system with two Nehalem processors was shown at Intel Developer Forum Fall 2007,[5] and a large number of Nehalem systems were shown at Computex in June 2008.
The microarchitecture is named after the Nehalem Native American nation in Oregon.[citation needed] The code name itself had been seen on the end of several roadmaps starting in 2000. At that stage it was supposed to be the latest evolution of the NetBurst microarchitecture. Since the abandonment of NetBurst, the codename has been recycled and refers to a completely different project, although Nehalem still has some things in common with NetBurst. Nehalem-based microprocessors utilize higher clock speeds and are more energy-efficient than Penryn microprocessors. Hyper-Threading is reintroduced along with an L3 Cache missing from most Core-based microprocessors.
The first computer to use Nehalem-based Xeon processors was the Apple Mac Pro workstation announced on March 3, 2009.[6] Nehalem-based Xeon EX processors for larger servers are expected in Q4 2009.[7] Mobile Nehalem-based processors are planned to follow in late 2009 or early 2010.
Technology
Various sources have stated the specifications of processors in the Nehalem family:
• Two, four, six, or eight cores
o 731 million transistors for the quad core variant
• 45 nm manufacturing process
• Integrated memory controller supporting two or three memory channels of DDR3 SDRAM or four FB-DIMM channels
• Integrated graphics processor (IGP) located off-die, but in the same CPU package[8]
• A new point-to-point processor interconnect, the Intel QuickPath Interconnect, in high-end models, replacing the legacy front side bus
• Integration of PCI Express and Direct Media Interface into the processor in mid-range models, replacing the northbridge
• Simultaneous multithreading (SMT) by multiple cores which enables two threads per core. Intel calls this hyper-threading. Simultaneous multithreading has not been present on a consumer desktop Intel processor since 2006 with the Pentium 4 and Pentium XE. Intel reintroduced SMT with their Atom Architecture.
• Native (monolithic, i.e. all processor cores on a single die) quad- and octa-core processors[9]
• The following caches:
o 32 KB L1 instruction and 32 KB L1 data cache per core
o 256 KB L2 cache per core
o 4–8 MB L3 cache shared by all cores
• 33% more in-flight micro-ops than Conroe[10]
• Second-level branch predictor and second-level translation lookaside buffer[10]
• Modular blocks of components such as cores that can be added and subtracted for varying market segments
Wednesday, October 27, 2010
Graphene-Based Reversible Nano-Switch
This device can extend applications of nanoelectronics to embedded bio-medical devices and explosive-detection devices.
This proof-of-concept device consists of a thin film of graphene deposited on an electrodized doped silicon wafer. The graphene film acts as a conductive path between a gold electrode deposited on top of a silicon dioxide layer and the reversible side of the silicon wafer, so as to form a Schottky diode. By virtue of the two-dimensional nature of graphene, this device has extreme sensitivity to different gaseous species, thereby serving as a building block for a volatile species sensor, with the attribute of having reversibility properties. That is, the sensor cycles between active and passive sensing states in response to the presence or absence of the gaseous species.
This proof-of-concept device consists of a thin film of graphene deposited on an electrodized doped silicon wafer. The graphene film acts as a conductive path between a gold electrode deposited on top of a silicon dioxide layer and the reversible side of the silicon wafer, so as to form a Schottky diode. By virtue of the two-dimensional nature of graphene, this device has extreme sensitivity to different gaseous species, thereby serving as a building block for a volatile species sensor, with the attribute of having reversibility properties. That is, the sensor cycles between active and passive sensing states in response to the presence or absence of the gaseous species.
HTAM
The amazing growth of the Internet and telecommunications is powered
by ever-faster systems demanding increasingly higher levels of processor
performance. To keep up with this demand we cannot rely entirely on
traditional approaches to processor design. Microarchitecture techniques used
to achieve past processor performance improvement–superpipelining, branch
prediction, super-scalar execution, out-of-order execution, caches–have made
microprocessors increasingly more complex, have more transistors, and
consume more power. In fact, transistor counts and power are increasing at
rates greater than processor performance. Processor architects are therefore
looking for ways to improve performance at a greater rate than transistor
counts and power dissipation. Intel’s Hyper-Threading Technology is one
solution.
by ever-faster systems demanding increasingly higher levels of processor
performance. To keep up with this demand we cannot rely entirely on
traditional approaches to processor design. Microarchitecture techniques used
to achieve past processor performance improvement–superpipelining, branch
prediction, super-scalar execution, out-of-order execution, caches–have made
microprocessors increasingly more complex, have more transistors, and
consume more power. In fact, transistor counts and power are increasing at
rates greater than processor performance. Processor architects are therefore
looking for ways to improve performance at a greater rate than transistor
counts and power dissipation. Intel’s Hyper-Threading Technology is one
solution.
FRAM
Before the 1950’s, ferromagnetic cores were the only type of
random-access, nonvolatile memories available. A core memory is a regular
array of tiny magnetic cores that can be magnetized in one of two opposite
directions, making it possible to store binary data in the form of a magnetic
field. The success of the core memory was due to a simple architecture that
resulted in a relatively dense array of cells. This approach was emulated in the
semiconductor memories of today (DRAM’s, EEPROM’s, and FRAM’s).
Ferromagnetic cores, however, were too bulky and expensive compared to the
smaller, low-power semiconductor memories. In place of ferromagnetic cores
ferroelectric memories are a good substitute. The term “ferroelectric’ indicates
the similarity, despite the lack of iron in the materials themselves.
Ferroelectric memory exhibit short programming time, low power
consumption and nonvolatile memory, making highly suitable for application
like contact less smart card, digital cameras which demanding many memory
write operations. In other word FRAM has the feature of both RAM and ROM.
A ferroelectric memory technology consists of a complementry metal-oxidesemiconductor
(CMOS) technology with added layers on top for ferroelectric
capacitors. A ferroelectric memory cell has at least one ferroelectric capacitor
to store the binary data, and one or two transistors that provide access to the
capacitor or amplify its content for a read operation.
A ferroelectric capacitor is different from a regular capacitor in that it
substitutes the dielectric with a ferroelectric material (lead zirconate titanate
(PZT) is a common material used)-when an electric field is applied and the
charges displace from their original position spontaneous polarization occurs
and displacement becomes evident in the crystal structure of the material.
random-access, nonvolatile memories available. A core memory is a regular
array of tiny magnetic cores that can be magnetized in one of two opposite
directions, making it possible to store binary data in the form of a magnetic
field. The success of the core memory was due to a simple architecture that
resulted in a relatively dense array of cells. This approach was emulated in the
semiconductor memories of today (DRAM’s, EEPROM’s, and FRAM’s).
Ferromagnetic cores, however, were too bulky and expensive compared to the
smaller, low-power semiconductor memories. In place of ferromagnetic cores
ferroelectric memories are a good substitute. The term “ferroelectric’ indicates
the similarity, despite the lack of iron in the materials themselves.
Ferroelectric memory exhibit short programming time, low power
consumption and nonvolatile memory, making highly suitable for application
like contact less smart card, digital cameras which demanding many memory
write operations. In other word FRAM has the feature of both RAM and ROM.
A ferroelectric memory technology consists of a complementry metal-oxidesemiconductor
(CMOS) technology with added layers on top for ferroelectric
capacitors. A ferroelectric memory cell has at least one ferroelectric capacitor
to store the binary data, and one or two transistors that provide access to the
capacitor or amplify its content for a read operation.
A ferroelectric capacitor is different from a regular capacitor in that it
substitutes the dielectric with a ferroelectric material (lead zirconate titanate
(PZT) is a common material used)-when an electric field is applied and the
charges displace from their original position spontaneous polarization occurs
and displacement becomes evident in the crystal structure of the material.
Spin Valve Transistor
In a world of ubiquitous presence of electrons can you imagine any other
field displacing it? It may seem peculiar, even absurd, but with the advent of
spintronics it is turning into reality.
In our conventional electronic devices we use semi conducting materials
for logical operation and magnetic materials for storage, but spintronics uses
magnetic materials for both purposes. These spintronic devices are more versatile
and faster than the present one. One such device is spin valve transistor.
Spin valve transistor is different from conventional transistor. In this for
conduction we use spin polarization of electrons. Only electrons with correct spin
polarization can travel successfully through the device. These transistors are used
in data storage, signal processing, automation and robotics with less power
consumption and results in less heat. This also finds its application in Quantum
computing, in which we use Qubits instead of bits
field displacing it? It may seem peculiar, even absurd, but with the advent of
spintronics it is turning into reality.
In our conventional electronic devices we use semi conducting materials
for logical operation and magnetic materials for storage, but spintronics uses
magnetic materials for both purposes. These spintronic devices are more versatile
and faster than the present one. One such device is spin valve transistor.
Spin valve transistor is different from conventional transistor. In this for
conduction we use spin polarization of electrons. Only electrons with correct spin
polarization can travel successfully through the device. These transistors are used
in data storage, signal processing, automation and robotics with less power
consumption and results in less heat. This also finds its application in Quantum
computing, in which we use Qubits instead of bits
WISENET
WISENET is a wireless sensor network that monitors the
environmental conditions such as light, temperature, and humidity. This
network is comprised of nodes called “motes” that form an ad-hoc network
to transmit this data to a computer that function as a server. The server stores
the data in a database where it can later be retrieved and analyzed via a webbased
interface. The network works successfully with an implementation of
one sensor mote.
The technological drive for smaller devices using less power with greater
functionality has created new potential applications in the sensor and data acquisition
sectors. Low-power microcontrollers with RF transceivers and various digital and analog
sensors allow a wireless, battery-operated network of sensor modules (“motes”) to
acquire a wide range of data. The TinyOS is a real-time operating system to address the
priorities of such a sensor network using low power, hard real-time constraints, and
robust communications.
The first goal of WISENET is to create a new hardware platform to
take advantage of newer microcontrollers with greater functionality and more features.
This involves selecting the hardware, designing the motes, and porting TinyOS. Once the
platform is completed and TinyOS was ported to it, the next stage is to use this platform
to create a small-scale system of wireless networked sensors.
environmental conditions such as light, temperature, and humidity. This
network is comprised of nodes called “motes” that form an ad-hoc network
to transmit this data to a computer that function as a server. The server stores
the data in a database where it can later be retrieved and analyzed via a webbased
interface. The network works successfully with an implementation of
one sensor mote.
The technological drive for smaller devices using less power with greater
functionality has created new potential applications in the sensor and data acquisition
sectors. Low-power microcontrollers with RF transceivers and various digital and analog
sensors allow a wireless, battery-operated network of sensor modules (“motes”) to
acquire a wide range of data. The TinyOS is a real-time operating system to address the
priorities of such a sensor network using low power, hard real-time constraints, and
robust communications.
The first goal of WISENET is to create a new hardware platform to
take advantage of newer microcontrollers with greater functionality and more features.
This involves selecting the hardware, designing the motes, and porting TinyOS. Once the
platform is completed and TinyOS was ported to it, the next stage is to use this platform
to create a small-scale system of wireless networked sensors.
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