FUSE/Lyman grant

A variety of options for a short wavelength spectrometer for the Lyman telescope has been studied, and the optimum configuration for this instrument identified. In this spectrometer option study it is assumed (consistent with performance goals outlined by the project) that the instrument, whose prime spectral domain is 900-12000A, will incorporate a grazing incidence telescope which will maintain good collecting efficiency down to 100A. In particular it is assumed that the telescope will have an effective focal length of 10 meters, an image quality of 1.5", and will provide a diverging f/10 beam. Designs compatible with this telescope are analyzed, and it is determined that a two-element grazing incidence spectrometer using as its first optic an ellipsoid to re-focus the beam and a varied line-space plane diffraction grating to disperse the light is the best overall design. This spectrometer could be fed by a small pick-off mirror located just behind the prime focus of the telescope and would clear the light path when not in use. A test of the diffraction efficiency of a low blaze angle grating is undertaken, which is the only technical uncertainty in the spectrometer design

Role of optimization in interdisciplinary analyses of naval structures

The need for numerical design optimization of naval structures is discussed. The complexity of problems that arise due to the significant roles played by three major disciplines, i.e., structural mechanics, acoustics, and hydrodynamics are discussed. A major computer software effort that has recently begun at the David W. Taylor Naval Ship R&D Center to accommodate large multidisciplinary analyses is also described. In addition to primarily facilitating, via the use of data bases, interdisciplinary analyses for predicting the response of the Navy's ships and related structures, this software effort is expected to provide the analyst with a convenient numerical workbench for performing large numbers of analyses that may be necessary for optimizing the design performance. Finally, an example is included that investigates several aspects of optimizing a typical naval structure from the viewpoints of strength, hydrodynamic form, and acoustic characteristics

Structural change in multipartite entanglement sharing: a random matrix approach

We study the typical entanglement properties of a system comprising two independent qubit environments interacting via a shuttling ancilla. The initial preparation of the environments is modeled using random-matrix techniques. The entanglement measure used in our study is then averaged over many histories of randomly prepared environmental states. Under a Heisenberg interaction model, the average entanglement between the ancilla and one of the environments remains constant, regardless of the preparation of the latter and the details of the interaction. We also show that, upon suitable kinematic and dynamical changes in the ancilla-environment subsystems, the entanglement-sharing structure undergoes abrupt modifications associated with a change in the multipartite entanglement class of the overall system's state. These results are invariant with respect to the randomized initial state of the environments.Comment: 10 pages, RevTeX4 (Minor typo's corrected. Closer to published version

Method of constructing exactly solvable chaos

We present a new systematic method of constructing rational mappings as ergordic transformations with nonuniform invariant measures on the unit interval [0,1]. As a result, we obtain a two-parameter family of rational mappings that have a special property in that their invariant measures can be explicitly written in terms of algebraic functions of parameters and a dynamical variable. Furthermore, it is shown here that this family is the most generalized class of rational mappings possessing the property of exactly solvable chaos on the unit interval, including the Ulam=Neumann map y=4x(1-x). Based on the present method, we can produce a series of rational mappings resembling the asymmetric shape of the experimentally obtained first return maps of the Beloussof-Zhabotinski chemical reaction, and we can match some rational functions with other experimentally obtained first return maps in a systematic manner.Comment: 12 pages, 2 figures, REVTEX. Title was changed. Generalized Chebyshev maps including the precise form of two-parameter generalized cubic maps were added. Accepted for publication in Phys. Rev. E(1997

The development of tape recorded discussions and check lists for evaluating progression in grades one through four.

Thesis (Ed.M.)--Boston Universit

Sturm theory, Ghys theorem on zeroes of the Schwarzian derivative and flattening of Legendrian curves

We discuss Ghys' theorem on 4 zeroes of the Schwarzian derivative and its relation with flattening points of Legendrian curves and Sturm theory.Comment: 14 pages, 7 postscript figures, anonymous ftp at ftp://cpt.univ-mrs.fr/ or gopher://cpt.univ-mrs.fr

Normal mode splitting in a coupled system of nanomechanical oscillator and parametric amplifier cavity

We study how an optical parametric amplifier inside the cavity can affect the normal mode splitting behavior of the coupled movable mirror and the cavity field. We work in the resolved sideband regime. The spectra exhibit a double-peak structure as the parametric gain is increased. Moreover, for a fixed parametric gain, the double-peak structure of the spectrum is more pronounced with increasing the input laser power. We give results for mode splitting. The widths of the split lines are sensitive to parametric gain.Comment: 7 pages,9 figure