tailieunhanh - The next great telecom revolution phần 4

Lidija Sekaric, tại một nhà nghiên cứu tại IBM Watson Research Center ở Yorktown Heights, New York, làm việc với Cornell tốt nghiệp sinh viên Keith Aubin và nhà nghiên cứu đại học Jingqing Huang các nanoguitar mới, lớn gấp năm lần so với bản gốc nhưng vẫn để nhỏ đó của mình hình dạng chỉ có thể được nhìn thấy trong kính hiển vi. | 56 NUTS AND BITS TELECOM HARDWARE SOFTWARE AND MORE Lidija Sekaric now a researcher at IBM s Watson Research Center in Yorktown Heights New York worked with Cornell graduate student Keith Aubin and undergraduate researcher Jingqing Huang on the new nanoguitar which is about five times larger than the original but still so small that its shape can only be seen in a microscope. Its strings are really silicon bars 150 by 200 nm in cross-section and ranging from 6 to 12 mm in length a micrometer is one-millionth of a meter a nanometer is a billionth of a meter the length of three silicon atoms in a row . The strings vibrate at frequencies 17 octaves higher than those of a real guitar or about 130 000 times higher. The researchers recently observed that light from a laser could cause properly designed small devices to oscillate and this effect underlies the nanoguitar design. The nanoguitar is played by hitting the strings with a focused laser beam. When the strings vibrate they create interference patterns in the light reflected back which can be detected and electronically converted down to audible notes. The device can play only simple tones although chords can be played by activating more than one string at a time. The pitches of the strings are determined by their length not by their tension as in a normal guitar but the group has tuned the resonances in similar devices by applying a direct current voltage. The generations of researchers to come can aim to play more complex pieces says Sekaric. This goal would indeed improve the science and technology of NEMS by aiming for integrated driving and detection schemes as well as a wide range of frequencies produced from a small set of vibrating elements. Most of the devices the group studies don t resemble guitars but the study of resonances often leads to musical analogies and the natural designs of the small resonant systems often leads to shapes that look like harps xylophones or drums. The guitar shape was Craighead