Stochastic assembly of sublithographic nanoscale interfaces

We describe a technique for addressing individual nanoscale wires with microscale control wires without using lithographic-scale processing to define nanoscale dimensions. Such a scheme is necessary to exploit sublithographic nanoscale storage and computational devices. Our technique uses modulation doping to address individual nanowires and self-assembly to organize them into nanoscale-pitch decoder arrays. We show that if coded nanowires are chosen at random from a sufficiently large population, we can ensure that a large fraction of the selected nanowires have unique addresses. For example, we show that N lines can be uniquely addressed over 99% of the time using no more than /spl lceil/2.2log/sub 2/(N)/spl rceil/+11 address wires. We further show a hybrid decoder scheme that only needs to address N=O(W/sub litho-pitch//W/sub nano-pitch/) wires at a time through this stochastic scheme; as a result, the number of unique codes required for the nanowires does not grow with decoder size. We give an O(N/sup 2/) procedure to discover the addresses which are present. We also demonstrate schemes that tolerate the misalignment of nanowires which can occur during the self-assembly process

The Vibrating String In Keyboard Instruments

In this thesis some aspects of the acoustics of the piano and harpsichord are discussed. Initially the wave equation for the vibrating string is derived. Since the strings in the piano are not perfectly flexible the wave equation is extended to take into account the stiffness of the strings. The wave equation thus modified affects the frequencies of the partials of the strings. The predicted frequencies are compared with the actual frequencies on a piano. The discussion is then continued to show how this affects the actual tuning of the instrument. Computer and programmable calculator programmes are used in these predictions. The theoretical basis for the spectra of piano and harpsichord strings are discussed and brief notes included on the effects of hammer width and string stiffness. The final experimental section deals with the reverberation times for piano and harpsichord strings, taking account of the effects of multiple stringing. Multiple stringing is found to affect the piano strings but not the harpsichord strings reverberation times. No accurate measurements of harpsichord reverberation times could be found in the literature, and the experiments were extended to include the effects of the buff stop. The conclusions contain several suggestions for further study and stress the importance of piano scaling. It is noted that scaling is also of importance to the musician when selecting instruments for the performance of duets, especially with regard to tuning compatibility

Swath Mapping on the Continental Shelf and Slope: The Eel River Basin, Northern California

First Paragraph The STRATAFORM program sponsored by the Office of Naval Research (Nittrouer and Kravitz, 1996, this issue) seeks to understand how sedimentary processes lead to the formation of the stratigraphic sequences on continental margins. A central challenge facing this effort is to understand the transport of sediments in shore-parallel as well as shore-perpendicular directions• Multidimensionality is necessary to describe, for example, the accumulation of sediments from river inputs, the distribution of gullies and canyons on the slope, the meandering of channels, and the structure of slumps and slides

The President’s Report, June 20, 1922

The President’s Report for June 20, 1922

The President’s Report, June 19, 1923

The President’s Report for June 19, 1923

The President’s Report, June 11, 1918

The President’s Report for June 11, 1918

The President’s Report, June 10, 1924

The President’s Report for June 10, 1924

The President’s Report, November 13, 1939

The President’s Report for November 13, 1939

Vocational guidance problems in a secondary shcool.

Typewritten sheets in cover. Thesis (M.A.)--Boston University This item was digitized by the Internet Archive