4,882 research outputs found
Investigation of land use of northern megalopolis using ERTS-1 imagery
The author has identified the following significant results. It was concluded that ERTS land use mapping, in spite of portraying megalopolis more accurately and dramatically than the best past efforts, is in danger of falling into the category of being too revolutionary for many planners and too conventional for many electronics engineers. Two alternative solutions are implied: one is to improve the ERTS product to the level where it will be completely accepted by planners, and the other is to increase support for the present somewhat primitive product through education, cost-sharing, and legislation
Properties from relativistic coupled-cluster without truncation: hyperfine constants of , , and
We demonstrate an iterative scheme for coupled-cluster properties
calculations without truncating the dressed properties operator. For
validation, magnetic dipole hyperfine constants of alkaline Earth ions are
calculated with relativistic coupled-cluster and role of electron correlation
examined. Then, a detailed analysis of the higher order terms is carried out.
Based on the results, we arrive at an optimal form of the dressed operator.
Which we recommend for properties calculations with relativistic
coupled-cluster theory.Comment: 13 pages, 4 figures, 5 table
Evaluation of ERTS-1 data for acquiring land use data of northern Megalopolis
State planners are increasingly becoming interested in ERTS as a possible method for acquiring land use data. An important consideration to them is whether ERTS can provide such data at a savings in both time and money over alternative systems. A preliminary evaluation of ERTS as a planning tool is given
Coupled-cluster calculations of properties of Boron atom as a monovalent system
We present relativistic coupled-cluster (CC) calculations of energies,
magnetic-dipole hyperfine constants, and electric-dipole transition amplitudes
for low-lying states of atomic boron. The trivalent boron atom is
computationally treated as a monovalent system. We explore performance of the
CC method at various approximations. Our most complete treatment involves
singles, doubles and the leading valence triples. The calculations are done
using several approximations in the coupled-cluster (CC) method. The results
are within 0.2-0.4% of the energy benchmarks. The hyperfine constants are
reproduced with 1-2% accuracy
Fock space relativistic coupled-Cluster calculations of Two-Valence Atoms
We have developed an all particle Fock-space relativistic coupled-cluster
method for two-valence atomic systems. We then describe a scheme to employ the
coupled-cluster wave function to calculate atomic properties. Based on these
developments we calculate the excitation energies, magnetic hyperfine constants
and electric dipole matrix elements of Sr, Ba and Yb. Further more, we
calculate the electric quadrupole HFS constants and the electric dipole matrix
elements of Sr, Ba and Yb. For these we use the one-valence
coupled-cluster wave functions obtained as an intermediate in the two-valence
calculations. We also calculate the magnetic dipole hyperfine constants of
Yb.Comment: 23 pages, 12 figures, 10 tables typos are corrected and some minor
modifications in some of the section
Investigation of land use of northern megalopolis using ERTS-1 imagery
Primary objective was to produce a color-coded land use map and digital data base for the northern third of Megalopolis. Secondary objective was to investigate possible applications of ERTS products to land use planning. Many of the materials in this report already have received national, dissemination as a result of unexpected interest in land use surveys from ERTS. Of special historical interest is the first comprehensive urban-type land use map from space imagery, which covered the entire state of Rhode Island and was made from a single image taken on 28 July 1972
Influence of the scattering potential model on low energy electron diffraction from Cu(001)−c(2 × 2)-Pb
A dynamical LEED intensity analysis is reported for Cu(001)−c(2 × 2)-Pb. The adsorbate layer distance from the substrate is determined as 2.29 Å, and the topmost interlayer spacing for the substrate is the same as in bulk Cu, in contrast to a contraction for clean Cu(001). This structural result is, within the accuracy reached, insensitive to changes in the assumed scattering potential models. The r-factors suggest a weak preference for an energy-dependent exchange correlation and a moderate one for adding a localized adsorption part inside the muffin-tin spheres. The sensitivity of spectra and r-factors to changes in the assumed isotropic Debye temperature for Pb suggests that vibrational anisotropy should be taken into account in order to improve the accuracy of the analysis. Calculated spin polarization spectra are very sensitive to the exchange approximation, the localized absorption and the Debye temperature. Together with experimental data, they should be useful in particular for determining the vibrational anisotropy
Relativistic coupled-cluster calculations of Ne, Ar, Kr and Xe: correlation energies and dipole polarizabilities
We have carried out a detailed and systematic study of the correlation
energies of inert gas atoms Ne, Ar, Kr and Xe using relativistic many-body
perturbation theory and relativistic coupled-cluster theory. In the
relativistic coupled-cluster calculations, we implement perturbative triples
and include these in the correlation energy calculations. We then calculate the
dipole polarizability of the ground states using perturbed coupled-cluster
theory.Comment: 10 figures, 6 tables, submitted to PR
Studies of thermionic materials for space power applications informal monthly report, oct. 1 - oct. 31, 1963
Thermionic space power material - isostatic pressing, vapor deposited tungsten, high temperature properties, cesium thermionic cell life testing, and irradiation studie
Theoretical determination of lifetimes of metastable states in Sc III and Y III
Lifetimes of the first two metastable states in Sc^{2+} and Y^{2+} are
determined using the relativistic coupled-cluster theory. There is a
considerable interest in studying the electron correlation effects in these
ions as though their electronic configurations are similar to the neutral
alkali atoms, their structures are very different from the latter. We have made
a comparative study of the correlation trends between the above doubly ionized
systems with their corresponding neutral and singly ionized iso-electronic
systems. The lifetimes of the excited states of these ions are very important
in the field of astrophysics, especially for the study of post-main sequence
evolution of the cool giant stars.Comment: 13 pages, 1 figure and 5 table
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