                  |
 Net World Directory Your personal directory for the internet | ||
| Net World Directory: Archives of technology blog |
 | ||
Archives Of Technology Blog From NetworlddirectorySubscribe To Technology Blog RSS Feed 
More Compact, Inexpensive Spectrometer A prototype spectrometer made using Georgia Tech’s new technology. The technology can improve the portability while reducing the size, complexity, and cost of a number of sensing and diagnostics systems that use spectrometers. The technology has appeared in Applied Optics, Optics Express and Optics Letters and was presented as an invited talk at the IEEE Lasers and Electro-Optics Society Annual Meeting 2005. Conventional spectrometers have multiple parts - a narrow slit, a lens (to guide light), a grating (to separate wavelengths), a second lens and a detector (to detect the power at different wavelengths). The Georgia Tech team's goal was to combine all these pieces into two parts, a volume hologram (formed in an inexpensive piece of polymer) and a detector, to create a compact, efficient and inexpensive spectrometer that could be used for multiple spectroscopy and sensing applications. "This technology is very useful for low-end spectrometers, but at the same time, there are a number of applications that require high-end spectrometers. This technology could convert a portion of a complex, high-end system into a much more versatile and light system," said Ali Adibi, head of the project and an associate professor in the School of Electrical and Computer Engineering......... Posted by: Kevin Permalink February 9, 2006, 10:48 PM CT Improving Distance Measurement The NIST laboratory system is an adaptation of light detection and ranging (LIDAR), which transmits light through the air to a target and analyzes the weak reflected signal to measure the distance, or range, to the target and other parameters. The NIST system uses an infrared laser that emits a continuous train of very brief, closely spaced pulses of light of a number of colors, or frequencies. An analysis of the frequencies reveals a very fine "comb" of evenly spaced teeth. The short pulse length (quadrillionths of a second, or millionths of a billionth of a second) creates a wide range of comb frequencies, enabling more accurate range measurements; the inherent stability of the laser creates fine comb teeth, enabling very precise vibration measurements. The frequency comb serves as both the light source and as a precise ruler for measuring the reflected signal. NIST-developed software analyzes the intensity of the reflected signal to measure distance to the target, and analyzes the frequency (or Doppler) shift to measure vibration. The most unusual aspect of the system is the way it resolves common problems with signal "noise" and dispersion of light by the atmosphere into longer pulses (with different colors of light traveling at different speeds). The reflected light that is detected is divided into many different color bands for computer processing. Measurements are averaged across the channels, effectively multiplying the precision of the result by the number of channels......... Posted by: Kevin Permalink February 9, 2006, 10:39 PM CT Stable Polymer Nanotubes Carbon nanotubes are of keen interest in nanotechnology research, particularly for making ultrastrong fibers and other structures. Nanotubes made from other materials are used for transport in biochemical applications, but are typically fragile and commonly collapse within a few hours. The NIST team developed processes for extending the shelf life of polymer nanotubes-considered essential for commercial applications-and forming sturdy nanotube network structures. First the scientists made tiny, fluid-filled spherical containers with bi-layer membranes consisting of polymers with one end that likes water and one end that does not. (These fluid-filled containers are a spin-off of liposomes, artificial cells with fatty membranes used in cosmetics and for drug delivery.) The scientists made the membranes stretchy by adding a soap-like fluid to change the polymer membranes' mechanical properties. Then they used "optical tweezers" (highly focused infrared lasers) or tiny droppers called micropipettes to pull on the elastic membranes to form long, double-walled tubes that are less than 100 nanometers in diameter......... Posted by: Kevin Permalink February 5, 2006, 11:00 PM CT Enhance Quantum Cryptography In research published recently in Applied Physics Letters, the team describes the use of new superconducting transition-edge sensors (TES) to distribute cryptographic key material at wavelengths of 1,550 nanometers through 50 kilometers of optical fiber. TES could provide increases in range and performance over current QKD photon detection schemes. Unlike the single-photon sensitive avalanche photodiodes (APD) that are typically used in optical fiber QKD systems, TESs detect photons by measuring minute temperature increases in a superconducting material caused by the absorption of individual photons. "The enhancements we've made," said Los Alamos quantum physicist Danna Rosenberg, "center around a new method of detecting single photons, which can be one of the most challenging aspects of QKD. The TESs provide significantly higher detection efficiencies and lower dark count rates than those of typical APDs. The high efficiency and low probability of dark counts, coupled with the relatively short recovery time of TESs, should permit higher secret key transmission rates at longer distances than APD-based systems"......... Posted by: Kevin Permalink February 5, 2006, 10:35 PM CT Laser-driven Ion Beams In a paper published in a recent issue of the scientific journal Nature, a team led by Los Alamos scientist Manuel Hegelich describe their method for the laser acceleration of a monoenergetic ion beam. The carbon ion beam scientists created using the Trident laser facility at Los Alamos had an energy level of 3 Megaelectronvolt (MeV) per nucleon, or 36 MeV. Researchers have known about laser-driven ion beams with energies in the MeV range for several years, but the Los Alamos team's experiment was the first to establish the basis for laser-driven acceleration of monoenergetic ion beams using specifically designed and treated targets. While the energy spread of laser-driven ion beams is still substantially larger than in conventional accelerators, in several respects they surpass conventional beams. As per Hegelich, "Typically you need a very large accelerator, the kind that only fits in a research hall, and that accelerates particles over distances of around a hundred meters, to accelerate an ion beam to the energies reported in our paper. Even then, the resulting ion pulses are longer and have weaker currents (milli- or even microamps versus kiloamps). Because conventional accelerators are currently pushing the limits in size and cost, laser acceleration is a potential solution to these challenges. The laser-driven ion accelerator we've developed fits in a typical-sized laboratory and the accelerate ions over a distance of roughly 10 microns"......... Posted by: Kevin Permalink February 1, 2006, 11:44 PM CT Getting the most form your Web Site The online business planning and strategy implementation begins once you have a fully functional, professional looking and optimized website. Measuring your online business is no mean task. Due to latest trends in dynamic content, you may put up a different promotional or discounts or deals on a weekly, monthly or even hourly basis. A baseline measure is possible only when you measure your business during a quite month of no promotional and deals are put up. This will indicate the performance of your online business more accurately and help you plan ahead. Keeping tabs on all happenings at the site should be monitored. Bringing visitors to your site is important. This is called traffic generation. But once the traffic arrives, it is your websites responsibility to make the visitor make a purchase. The number of purchases compared against the traffic is called the conversion rate. The conversion rate can only be bettered by your website through promotional, discounts or deals or any other way you think fit......... Posted by: Kevin Permalink February 1, 2006, 10:08 PM CT Website Technologies On The Go In your web browser, Client Side technologies use HTML, XHTML and CSS in order to create web sites. HTML is short for Hyper Text Markup Language. This is a manner of labeling text so that the computer can understand what it means and what it wants. If we are to trace its humble beginning, HTML was created by Tim-Berners-Lee in the year 1990. This creation was acknowledged by the W3C or the World Wide Web Consortium. The use of a series of 'tags' is the function of HTML. To emphasize a word, say to make the word 'mike' bold, here is the right tag - mike The result of which is this - mike. In order to come up with a whole site, series of appropriate tags is indispensable. After HTML came XHTML. This technology means eXtended Hyper Text Markup Language. It is foretold to constitute a big part of the world wide web's future. The project of the W3C called "The Semantic Web" will be utilizing more of XHTML as well as other latest technologies. This will bring about a modern change that we never expected since 1990......... Posted by: Kevin Permalink January 31, 2006, 0:29 AM CT 4,800 Miles To Make Molecular Repositories The BioSimGrid was organized to support research at the universities of Oxford, Southampton, Bristol, Birkbeck, Nottingham and York. Scientists are seeking to learn more about some of the most fundamental building blocks of life. As per Doug Ray, chief research officer at PNNL, collaboration with scientists at these institutions, which rank among the world leaders in biological science, positions PNNL to contribute to breakthroughs in scientific understanding that could have tremendous impact on the environment, energy, security and everyday life. Grid technology is a distributed computing environment that allows access to extremely large files in disparate formats at far-ranging locations, which is the very description of data sets resulting from biomolecular simulations. Molecules may be small, but the data sets resulting from computer simulations of their behavior at atom-level resolution are huge, ranging in size from gigabytes to terabytes. The extreme file sizes mean simulation data generally resides in the home laboratory where the research was conducted and, for practical purposes, remains inaccessible to other research groups......... Posted by: Kevin Permalink January 31, 2006, 0:22 AM CT Fingerprints To Nanofiber The new technique is based on the way forensic researchers develop fingerprints from a crime scene and is easier and more versatile than either of the current methods, templates or electrospinning, used commercially to make nanofibers. The first nanofibers generated by the technique are made from the basic ingredient of Super Glue', cyanoacrylate, which is a biologically-compatible material already used in liquid sutures, spheres for drug delivery and in experimental cancer therapy. However, the scientists say that other materials, like cyanoacrylate, that form solid polymers when nudged by a catalyst could potentially also be used in the process. Dr. Henry C. Foley, professor of chemical engineering who directed the project, says, "The new technique is so versatile that it allows us not only to make nano-scale fibers but also nano-sized flat sheets, spheres and even wrinkled sheets that look tortellini-like." The scientists can also generate patterned surfaces and say that the process could conceivably be used in an ink jet printer......... Posted by: Kevin Permalink January 30, 2006, 11:39 PM CT Teaching Computers To Recognize Patterns This work may impact research in areas as diverse as genetics, economics, climate modeling, and neuroscience. Aleix Martinez, assistant professor of electrical and computer engineering at Ohio State, explained what all these areas of research have in common: pattern recognition. He designs computer algorithms to replicate human vision, so he studies the patterns in shape and color that help us recognize objects, from apples to friendly faces. But much of today's research in other areas comes down to finding patterns in data -- identifying the common factors among people who develop a certain disease, for example. In fact, the majority of pattern recognition algorithms in science and engineering today are derived from the same basic equation and employ the same methods, collectively called linear feature extraction, Martinez said. But the typical methods don't always give scientists the answers they want. That's why Martinez has developed a fast and easy test to find out in advance which algorithms are best in a particular circumstance. "You can spend hours or weeks exploring a particular method, just to find out that it doesn't work," he said. "Or you could use our test and find out right away if you shouldn't waste your time with a particular approach."........ Posted by: Kevin Permalink |
||
| Net World Directory: Navigation |