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Light emitting diodes (LEDs ) are opto-electronic components that emit light . They have long remained confined to single or infrared lights , but advances behind these years have greatly expanded their scope and are now regarded as a future technology .
The LED technology combines indeed many advantages: performance and energy conservation foremost, but also compactness , strength, durability, maintenance, virtually no light inertia , etc. . Their price seems to be their only fault . Yet recent developments and policies to encourage energy savings make them more interesting and it was announced a few years since their massive entry into the world of street lighting , interior and motor . LEDs are also found behind our screens and in our mobile phones.
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A team of researchers from the CSIR (Council for Scientific and Industrial Research) have developed a new technique of reloading laser that can repair cracks and seal leaks in power plants. Reloading is a laser overlay welding technique which involves depositing on the surface of a piece with a layer of material of different nature. The filler metal is transported in the form of wire or powder by an inert gas and injected laterally or coaxially into the laser beam.
Subject to a simplified application for a patent, welding technology by laser beam and fixing leaks, developed in collaboration with engineers from Eskom, will facilitate the maintenance of power plants, and especially to seal and repair leaks cooling systems without making prior discharge.
The welding unit and reloading laser is mobile and able to intervene on several floors of structures, the central laser being firmly fixed on the ground. A remote control helps guide the operations from the ground.
Source:
CSIR eNews: March 2010 – http://www.csir.co.za/enews/2010_mar/16.html
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Researchers at the Institute of Automation and electrometric the Siberian Branch of Russian Academy of Sciences have created with their colleagues at Aston University (Birmingham, Great Britain), the fiber laser as throughout the world: 300 km. The researchers believe that this is the furthest distance at which the optical fiber allows radiation of long wavelengths of 1.5 microns to propagate with minimal losses.
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For the first time, scientists at the Karlsruhe Institute of Technology [1] (Baden-Wurttemberg) and Imperial College London [2] have managed to make invisible objects in three dimensions of space the wavelength interval from 1.5 to 2.6 micrometers.
The experiment has been performed successfully on a small object the size of a micrometer. It is hidden behind a hump in a piece of meta-material [3] covered with a tiny gold film. With specific optical properties of meta-material, the emergence of the bump is not detectable. The user has the impression of observing a uniformly flat plate, the purpose behind the hump is found hidden. Prof. Martin Wegener and its Working Group of the Research Centre from the DFG (Deutsche Forschungsgemeinschaft) for Functional Nanostructures (CFN) explained that “the results represent real progress. Until then, cloaks of invisibility to bases waveguides allowed only to hide objects in two dimensions. As soon as the observer ventured into the third dimension, the object reappeared.
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The St. Paul’s Cathedral in London houses a gallery called Whispering Gallery and Gallery of murmurs, a circular space topped by a majestic dome. Two people, each with a dome, can speak as if they were nearby. Most of this acoustic phenomenon lies in the mysterious successive reflections of sound on the curved walls of the vault: the sound from the first person happens along the arc to the other side where stands the second person, without losing intensity noise. A similar phenomenon can be observed in objects one million times smaller, called micro-resonators, with one difference: in these small objects is replaced by the sound of light. Due to this similarity, the propagation of light waves in the microscale objects is called whispering gallery Mode (WGM), or whispering gallery modes and the field of photonics in recent times there is an interest.
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Thomas Rachel, Parliamentary State Secretary of Ministry of Education and Research (BMBF), announced at the show “Light & Building” (Light and Building) [1] Frankfurt (Hesse) Cities Germany would in future adopt a new lighting technology based on light emitting diodes (LEDs). During the day, were announced the winners of the competition entitled “A New Light for Cities” [2], organized jointly by the BMBF and the association of electronics and electrical industry (ZVEI). Each of the selected projects has been allocated a budget of up to two million euros. According to Thomas Rachel: “This shows that LEDs are indeed the key technology of the 21st century in terms of lighting.
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For the first time, scientists from the Institute of Technology Karlsruhe [1] (Baden-Wurttemberg) and Imperial College London [2] have managed to make invisible objects in three dimensions of space the range of wavelengths ranging from 1.5 to 2.6 micrometers.
The experiment has been performed successfully on a small object the size of a micrometer. It is hidden behind a bump located in a plate of meta-material [3] covered with tiny gold film. With specific optical properties of meta-material, the emergence of the bump is not detectable. The user has the impression of observing a uniform flat plate, the purpose behind the hump is found hidden. Professor Martin Wegener and its Working Group of the Research Center of the DFG (Deutsche Forschungsgemeinschaft) for Functional Nanostructures (CFN) explain that “the results constitute real progress. Until then, the invisibility cloaks to bases waveguides allowed only to hide objects in two dimensions. As soon as the observer ventured into the third dimension, the object reappeared.
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The St. Paul’s Cathedral in London houses a gallery called Whispering Gallery and Gallery of murmurs, a circular space topped by a majestic dome. Two people, each with a dome, can speak as if they were nearby. Most of this mysterious phenomenon sound hiding in the successive his reflections on the curved walls of the vault: the sound from the first person happens along the arc to the other side where stands the second person, without losing sound intensity. A similar phenomenon can be observed in objects one million times smaller, called micro-resonators, with one difference: in these small objects the sound is replaced by light. Because of this similarity, the propagation of light waves in micron-sized objects is called whispering gallery mode (WGM) or gallery modes and the field of photonics there is recently a special interest.
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Researchers at the University of Calgary have managed to use quantum entanglement to stack the light particles.
Although many of us enjoy riding small houses with pieces of building a game when we were children, this task is much more difficult if the pieces are elementary particles. It is even more difficult if these particles are photons, since they often move far too quickly and “disappear” with relative ease.
A team from the University of Calgary has accomplished exactly that: The strategy of manipulating a mysterious quantum property of light known as quantum entanglement, is able to amass two photons, one above the other, to construct various quantum states of light, ie following the analogy above, build toy houses quantum two-piece or two floors, and any possible style and architecture.
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A team of scientists from the Lebedev Physical Institute (FIAN), depending on the Academy of Sciences of Russia, managed to create a carbon dioxide laser, which allows to uncover the atmosphere in a range of pollutants, including including toxic and explosive. The new laser can be set to more than 400 lines of the spectrum, a wavelength between 2.5 and 4 micro-m and 5 to 6.5 micro-m. The particularity of this new device allows spectroscopic detection in complex mixtures of air smaller narcotics, toxic or explosive.
The idea of such a laser came in 2000 with a team of researchers led by doctoral student in physics and mathematics Dmitry Sinitsyn.
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