A Positron Named Priscilla Scientific Discovery at the Frontier (1994) / Chapter Skim
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Appendix A: Abstracts of Additional Sessions of the Frontiers of Science of Science Symposia
Appendix A: Abstracts of Additional Sessions of the Frontiers of Science of Science Symposia
Pages 316-327
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From page 316... ...
, to modulate or switch an optical signal. In preparing materials that show nonlinear optical activity, a standard approach has featured the use of polarizable molecules.
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From page 317... ...
Most of the rest have been discovered only since about 1975 and merit further research. Because organic chemistry offers great freedom in modifying molecular structures, it suggests the prospect of creating families of related materials that display novel types of magnetism in varying degrees.
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From page 318... ...
It might result from atmospheric dynamics, with ozone-poor air rising from below to dilute the air of the stratosphere. Alternately, the ozone hole might result from increased solar activity during the 11-year sunspot cycle, for energetic solar particles might stimulate formation of nitrogen oxides, which destroy ozone.
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From page 319... ...
Each ClO molecule should destroy a substantial number of ozone molecules, while being regenerated following each such molecular reaction. Aircraft observations indeed show that in late August, during the antarctic winter, elevated concentrations of ClO exist at high southern latitudes.
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From page 320... ...
The part of the homotopy groups of spheres constructed with this method is called the image of i, and this appears as the n = 1 monochromatic layer. The second monochromatic layer has been calculated by the topologist Katsumi Shimomura in 1986.
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From page 321... ...
An unknot is a simple closed curve in three-space that can be deformed into a round circle. Alan Hatcher has shown that the deforming or untangling is continuous and involves no choices.
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From page 322... ...
Meeting these conditions, however, permits growth of multilayer structures featuring different materials, which have the crystallography of single crystals. Two basic classes of deposition techniques are in use: physical vapor deposition (PVD)
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From page 323... ...
A topic of current research is the pursuit of bulk semiconductor materials possessing large densities of quantum wires or dots, which are to be approximately uniform in size. At Caltech another approach to fabrication of quantum structures takes the precise thickness control for one-dimensional layers that has been developed for formation of quantum wells and extends it into two and three dimensions to fabricate quantum wires and quantum dots.
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From page 324... ...
At the KTB, though, the dinosaurs also go extinct. Ian Smit of the Free University of Amsterdam, along with Walter Alvarez and his colleagues Alessandro Montanari and Nicola Swinburne of the University of California at Berkeley, have explored the candidate impact site: a 300-kilometer-diameter crater centered near the town of Chicxulub in northern Yucatan.
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From page 325... ...
Certainly, a 10-kilometer bolide would have produced vast environmental stress. Blast and tsunami would have affected only part of the earth, but the impact could have produced great quantities of nitrogen oxides, yielding a rainfall resembling nitric acid.
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From page 326... ...
This field features such applications as real-time interactive graphics used in flight simulation for pilot training; presentation of data in multiple variables or dimensions, including solutions for partial differential equations; and generation of computational grids. In all these areas a central problem is the rapid division of manysided polygons into constituent triangles.
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From page 327... ...
Tom Leighton, of the Massachusetts Institute of Technology, notes that randomly wired interconnected networks represent a useful alternative. Such networks are not wholly random; the randomness is subject to constraints.
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