Word: electronics
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...make transistors and chips, scientists "dope" a semiconducting material ike silicon with impurities, creating regions that have either an excess or a deiciency of electrons-and thus are negatively (n zones) or positively (p zones) charged. If two n zones, say, are separated by a p zone, they act like an electronic switch, or transistor; a small voltage in the p zone controls fluctuations in the current flowing between the n zones. But every time an excess electron is released in the n zone to join the current flow, it leaves behind a positively charged spot. Because opposite charges attract...
...create what in effect is an electron freeway without these obstructing potholes, Bell Physicist Raymond Dingle and his colleagues built a semiconductor made of extremely thin, alternate layers of aluminum gallium arsenide (which they doped) and gallium arsenide (which they left pure). They reasoned that any electrons donated by the impurity would tend to migrate to the adjoining undoped gallium arsenide layer because of their tendency to seek what physicists call a lower energy state. Explains the Australian-born Dingle: "It's rather like the inclination of water to flow downhill." The new design worked. Isolated from the obstructing...
Where will it all end? Circuits in some densely packed chips are already so close that there is sometimes electron leakage between conductors-interfering with the proper working of the chip. Is technology fast reaching the limit of miniaturization? Computer scientists think not. They point to the stupendous amounts of data contained, for example, in a DNA molecule-or in one-celled animals and plants that are visible only under a microscope. Says M.I.T.'s Michael Dertouzos...
...until 1933 that a virus was identified as the cause of flu and dubbed influenza A. In 1946-47 another form of A emerged, and about this time virologists working with electron microscopes made an important discovery. They found that the outer coat of each virus particle is studded with hundreds of protein spikes. There are two types: hemagglutinin, a biochemical glue that makes red cells clump together and helps the virus get into cells, and an enzyme called neuraminidase that dissolves the glue and helps the virus get out of cells. These spikes are also the antigenic proteins that...
What has hit the Soviet Union is a microbe that is invisible except to devices like the electron-microscope eye: an influenza virus. It appears to have surfaced first hi Khabarovsk, on the border between Soviet Siberia and Chinese Manchuria. (Soviet sources suggested that it might have originated in Southeast Asia as it has appeared in Hong Kong.) For obscure reasons, the Siberia-Manchuria border and nearby areas are suspected of having been the spawning ground of almost all, if not all, epidemic-causing influenza viruses. This region has been indicted as the birthplace of the notorious A-2 strain...