Revolutionary

This section will concentrate on the motions of atoms within molecules— internal molecular motions —as comprehended by the revolutionary quantum ideas of the 20th century. Necessarily, limitations of space prevent many topics from being treated in the detail they deserve. Some of these are treated in more detail in... 

Several factors detennine how efficient impurity atoms will be in altering the electronic properties of a semiconductor. For example, the size of the band gap, the shape of the energy bands near the gap and the ability of the valence electrons to screen the impurity atom are all important. The process of adding controlled impurity atoms to semiconductors is called doping. The ability to produce well defined doping levels in semiconductors is one reason for the revolutionary developments in the construction of solid-state electronic devices. 

Trace-element analysis, using emission spectroscopy (107) and, especially, activation analysis (108) has been appHed in provenance studies on archaeological ceramics with revolutionary results. The attribution of a certain geographic origin for the clay of an object excavated elsewhere has a direct implication on past trade and exchange relationships. 

Ironmaking in the United States did not expand rapidly until after the Revolutionary War. Then, as the colonists moved westward, the need for iron prompted the estabUshment of ironworks near the new settiements. A blast furnace built by Jacob Anschut2 in 1796 was the beginning of the iron and steel center in Pittsburgh, Pennsylvania. 

In summary, laser-based fiber-optic telecommunications has had a revolutionary impact on long-distance telephone communication and is now expanding into many new appHcations areas. 

The revolutionary development of stereospecific polymerization by the Ziegler-Natta catalysts also resulted ia the accomplishment ia the 1950s of a 100-year-old goal, the synthesis of i7j -l,4-polyisoprene (natural mbber). This actually led to the immediate termination of the U.S. Government Synthetic Rubber Program ia 1956 because the technical problem of dupHcating the molecular stmcture of natural mbber was thereby solved, and also because the mbber plantations of the Far East were again available. 

Driven by these impending limits to blade cooling emphasis has switched back to materials development. Because of the saturation in the development of nickel alloys, more revolutionary approaches are being explored. 

When Max Planck wrote his remarkable paper of 1901, and introduced what Stehle (1994) calls his time bomb of an equation, e = / v , it took a number of years before anyone seriously paid attention to the revolutionary concept of the quantisation of energy the response was as sluggish as that, a few years later, whieh greeted X-ray diffraction from crystals. It was not until Einstein, in 1905, used Planck s concepts to interpret the photoelectric effect (the work for which Einstein was actually awarded his Nobel Prize) that physicists began to sit up and take notice. Niels Bohr s thesis of 1911 which introduced the concept of the quantisation of electronic energy levels in the free atom, though in a purely empirical manner, did not consider the behaviour of atoms assembled in solids. 

Fadem, L. and Fadem, S.Z., Bakelite a revolutionary early plastic, http //www.deco-echoes.com/bakelite.html. Deco Echoes, 1996. 

We cannot now foresee the ultimate achievements of humankind in the fields of complex molecular synthesis. However, anyone familiar with the progress made in the field over the past century and one half would be foolish indeed to expect anything less than revolutionary advances in sophistication, efficiency and power. 

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