23,268 research outputs found
A 128K-bit CCD buffer memory system
A prototype system was implemented to demonstrate that CCD's can be applied advantageously to the problem of low power digital storage and particularly to the problem of interfacing widely varying data rates. 8K-bit CCD shift register memories were used to construct a feasibility model 128K-bit buffer memory system. Peak power dissipation during a data transfer is less than 7 W., while idle power is approximately 5.4 W. The system features automatic data input synchronization with the recirculating CCD memory block start address. Descriptions are provided of both the buffer memory system and a custom tester that was used to exercise the memory. The testing procedures and testing results are discussed. Suggestions are provided for further development with regards to the utilization of advanced versions of CCD memory devices to both simplified and expanded memory system applications
The GPRIME approach to finite element modeling
GPRIME, an interactive modeling system, runs on the CDC 6000 computers and the DEC VAX 11/780 minicomputer. This system includes three components: (1) GPRIME, a user friendly geometric language and a processor to translate that language into geometric entities, (2) GGEN, an interactive data generator for 2-D models; and (3) SOLIDGEN, a 3-D solid modeling program. Each component has a computer user interface of an extensive command set. All of these programs make use of a comprehensive B-spline mathematics subroutine library, which can be used for a wide variety of interpolation problems and other geometric calculations. Many other user aids, such as automatic saving of the geometric and finite element data bases and hidden line removal, are available. This interactive finite element modeling capability can produce a complete finite element model, producing an output file of grid and element data
and Perelomov number coherent states: algebraic approach for general systems
We study some properties of the Perelomov number coherent states.
The Schr\"odinger's uncertainty relationship is evaluated for a position and
momentum-like operators (constructed from the Lie algebra generators) in these
number coherent states. It is shown that this relationship is minimized for the
standard coherent states. We obtain the time evolution of the number coherent
states by supposing that the Hamiltonian is proportional to the third generator
of the Lie algebra. Analogous results for the Perelomov
number coherent states are found. As examples, we compute the Perelomov
coherent states for the pseudoharmonic oscillator and the two-dimensional
isotropic harmonic oscillator
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Results of an Examination of Metal Specimens from an Excavation of Shamshir Ghar, Afghanistan
Author Institution: Department of Chemistry, The Ohio State University, Columbu
Melting of Polydisperse Hard Disks
The melting of a polydisperse hard disk system is investigated by Monte Carlo
simulations in the semigrand canonical ensemble. This is done in the context of
possible continuous melting by a dislocation unbinding mechanism, as an
extension of the 2D hard disk melting problem. We find that while there is
pronounced fractionation in polydispersity, the apparent density-polydispersity
gap does not increase in width, contrary to 3D polydisperse hard spheres. The
point where the Young's modulus is low enough for the dislocation unbinding to
occur moves with the apparent melting point, but stays within the density gap,
just like for the monodisperse hard disk system. Additionally, we find that
throughout the accessible polydispersity range, the bound dislocation-pair
concentration is high enough to affect the dislocation unbinding melting as
predicted by Kosterlitz, Thouless, Halperin, Nelson and Young.Comment: 6 pages, 6 figure
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