The dissociation energy and the equilibrium bond length are calculated for CIO at the first order CI level for a variety of basis sets, consisting of both standard atomic centered basis sets and those including bond f...
The dissociation energy and the equilibrium bond length are calculated for CIO at the first order CI level for a variety of basis sets, consisting of both standard atomic centered basis sets and those including bond functions. The basis sets with bond function are found to have a CI superposition error many times that of the standard atomic centered basis sets.
Using ab initio (with effective core potentials) electronic structure theory, the equilibrium geometry and singlet-triplet separation were determined for CBr2. The triplet was computed by using a single-configuration ...
A simple method, requiring the work of a single SCF iteration, is presented for the construction of modified virtual orbitals (MVO's). Test calculations on H2O, Ar, and two states of CH2 show that for the truncati...
The problem of optimally partitioning a modular program over a dual processor system is of relevance to the numerous dual and multiple processor systems that now exist in both academic and industrial environments. Th...
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The problem of optimally partitioning a modular program over a dual processor system is of relevance to the numerous dual and multiple processor systems that now exist in both academic and industrial environments. The problem is to minimize the total running cost of the program, where cost may be measured in time, dollars, or other resource units. In the analysis of this problem, total cost has 2 components: 1. the cost of executing each module, and 2. the cost of intermodule communications between pairs of modules when they are resident on different processors. One formulation of the problem includes the cost of dynamically reassigning a module from one processor to the other and the cost of module residence without execution. By relocating modules during the course of program execution, changes in the locality of the program can be taken into account. Network flow algorithms can be used to find a dynamic assignment that minimizes the sum of module execution costs, module residence costs, intermodule communication costs, and module reassignment costs. Figures.
The scattering of the sound of a jet engine by an airplane fuselage is modelled by solving the axially symmetric Helmholtz equation exterior to a long thin ellipsoid. The integral equation method based on the single l...
The scattering of the sound of a jet engine by an airplane fuselage is modelled by solving the axially symmetric Helmholtz equation exterior to a long thin ellipsoid. The integral equation method based on the single layer potential formulation is used. A family of coordinate systems on the body is introduced and an algorithm is presented to determine the optimal co-ordinate system. Numerical results verify that the optimal choict enables the solution to be computed with a grid that is coarse relative to the wavelength.
Recently two dissection algorithms (one-way and incomplete nested dissection) have been developed for solving the sparse positive definite linear systems arising from n by n grid problems. Concurrently, vector compute...
A least squares method is presented for computing approximate solutions of indefinite partial differential equations of the mixed type such as those that arise in connection with transonic flutter analysis. The mehod ...
The problem of the specification of artifical outflow conditions in flow problems is studied. It is shown that for transport type equations incorrect outflow conditions will adversely affect the solution only in a sma...
During the past several years, many radars have observed the distinct and interesting features associated with the Gulf Stream and its boundaries. Some of these Gulf Stream radar features have small scale, with dimens...
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During the past several years, many radars have observed the distinct and interesting features associated with the Gulf Stream and its boundaries. Some of these Gulf Stream radar features have small scale, with dimensions comparable to and slightly greater than long gravity waves. Other features are larger, with dimensions much greater than the length of long gravity waves. This study describes radar cross section variations within the Gulf Stream and just outside, seen with a "scatterometer" type measurement. The significant features of this radar cross section data were that the Gulf Stream always had a higher cross section per unit area (interpreted here as a greater roughness) than the water on the continental shelf. Also, a steep gradient in cross section was often seen at the expected location of the western boundary. There were also longer scale (10 to 20 km) gradual fluctuations within the stream of significant magnitude. These roughness variations are correlated with the surface shear stress that the local wind imposes on the sea. Using the available surface truth information regarding the wind speed and direction, an assumed Gulf Stream velocity profile, and high resolution ocean surface temperature data obtained by the Very High Resolution Radiometer onboard a NOAA-NESS polar-orbiting satellite (data provided by Dr. Richard Legeckis of NOAA-NESS), this study demonstrates that the computed surface stress variation bears a striking resemblence to the measured radar cross-section variations.
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