CaltechAUTHORS: Book Chapter
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A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenTue, 15 Oct 2024 19:09:45 -0700Parallel homotopy algorithm for large sparse generalized eigenvalue problems: Application to hydrodynamic stability analysis
https://resolver.caltech.edu/CaltechAUTHORS:20170802-124308426
Year: 1992
DOI: 10.1007/3-540-55895-0_427
A parallel homotopy algorithm is presented for finding a few selected eigenvalues (for example those with the largest real part) of Az = λBz with real, large, sparse, and nonsymmetric square matrix A and real, singular, diagonal matrix B. The essence of the homotopy method is that from the eigenpairs of Dz = λBz, we use Euler-Newton continuation to follow the eigenpairs of A(t)z = λBz with A(t) ≡ (1−t)D + tA. Here D is some initial matrix and "time" t is incremented from 0 to 1. This method is, to a large degree, parallel because each eigenpath can be computed independently of the others. The algorithm has been implemented on the Intel hypcrcubc. Experimental results on a 64-nodc Intel iPSC/860 hypercube are presented. It is shown how the parallel homotopy method may be useful in applications like detecting Hopf bifurcations in hydrodynamic stability analysis.https://resolver.caltech.edu/CaltechAUTHORS:20170802-124308426Hyperpolarizabilities of Push—Pull Polyenes Molecular Orbital and Valence-Bond Charge-Transfer Models
https://resolver.caltech.edu/CaltechAUTHORS:20180406-080326593
Year: 1995
DOI: 10.1021/bk-1995-0601.ch003
In this paper we review two theoretical approaches that illustrate the relationships between molecular (hyper)polarizabilities and bondlength alternation (BLA). In one approach, we employ sum-overstates calculations at the INDO-SDCI level on (CH_3)_2N-(CH=CH)_4-CHO, including an external, static, homogeneous electric field that unes the degree of ground-state polarization and BLA. In the second approach, we use a simple semiclassical model, wherein the mixing of valence bond (VB) and charge-transfer (CT) states along a BLA coordinate is treated. Qualitatively, the two approaches give very similar structure-property trends, that are consistent with experimental hyperpolarizability data on donor-acceptor polyenes. The agreement of the calculated trends reflects the importance of VB-CT energetics in determining them.https://resolver.caltech.edu/CaltechAUTHORS:20180406-080326593Integrated heterodyne array receivers for submillimeter astronomy
https://resolver.caltech.edu/CaltechAUTHORS:20180702-143246207
Year: 2003
DOI: 10.1117/12.459375
The advent of large format (~100 pixel) spectroscopic imaging cameras at submillimeter wavelengths would fundamentally change the way in which astronomy is performed in this important wavelength regime. While the possibility of such instruments has been discussed for more than two decades, only recently have advances in mixer technology, device fabrication, micromachining, digital signal processing, and telescope design made the construction of such an instrument possible and economical. In our paper, we will present the design concept for a 10×10 heterodyne camera.https://resolver.caltech.edu/CaltechAUTHORS:20180702-143246207