67 lines
2.2 KiB
Plaintext
67 lines
2.2 KiB
Plaintext
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(word processor parameters LM=1, RM=70, TM=2, BM=2)
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Taken from KeelyNet BBS (214) 324-3501
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Sponsored by Vangard Sciences
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PO BOX 1031
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Mesquite, TX 75150
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Excitons
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From Washington Post on 5 Feb. 90 via Dallas News Paper
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Scientist' experiments focus on making better microscope
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Scientists have achieved the first step toward the invention
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of an entirely new kind of microscope that they predict could be
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able to see objects as small as the individual molecules in a
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living cell.
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While the electron microscope can see molecules, it will not
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work on living subjects at normal temperatures and pressures.
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The new procedure, called "molecular exciton microscopy,"
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promises to do this because it uses a modified form of ordinary
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light. The smallest object visible with a light microscope is
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roughly the size of the shortest wavelength of visible light,
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which is blue and measures about 400 nanometers (a nanometer is a
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billionth of a meter).
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This is small, but still so big that a single ray
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illuminates manymolecules at one time, masking differences. The
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new method, reported in the Journal of Science by Aaron Lewis of
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Hebrew University in Jerusalem and Raoul Kopelman of the
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University of Michigan and their colleagues, squeezes light waves
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into far smaller dimensions.
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They did it by shining light through a funnel with an
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extremely tiny tip. When photons, particles of light, reach the
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tip, they are absorbed by a crystal of anthracene. Inside the
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crystal, the photons become excitons (a combination of an
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electron and a "hole," an electrically charged void). Excitons
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are far, far smaller than an atom. As they emerge from the tip
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of the funnel, they are reborn as photons.
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contributed by Ron Moore
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