Results 341 to 350 of about 13,167,523 (376)

Density-equicontinuity and Density-sensitivity

Acta Mathematica Sinica, English Series, 2021
In this paper we introduce the notions of (Banach) density-equicontinuity and density-sensitivity. On the equicontinuity side, it is shown that a topological dynamical system is density-equicontinuous if and only if it is Banach density-equicontinuous. On the sensitivity side, we introduce the notion of density-sensitive tuple to characterize the multi-
Jie Li, Siming Tu
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Improved methods for building protein models in electron density maps and the location of errors in these models.

Acta Crystallographica Section A Foundations of Crystallography, 1991
Map interpretation remains a critical step in solving the structure of a macromolecule. Errors introduced at this early stage may persist throughout crystallographic refinement and result in an incorrect structure.
T. Jones, J. Zou, S. Cowan, M. Kjeldgaard, Serge HAGgGE   +4 more
semanticscholar   +1 more source

Toward reliable density functional methods without adjustable parameters: The PBE0 model

, 1999
We present an analysis of the performances of a parameter free density functional model (PBE0) obtained combining the so called PBE generalized gradient functional with a predefined amount of exact exchange.
C. Adamo, V. Barone
semanticscholar   +1 more source

Ab Initio Calculation of Vibrational Absorption and Circular Dichroism Spectra Using Density Functional Force Fields

, 1994
: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio.
P. Stephens, F. Devlin, C. Chabalowski, M. Frisch   +3 more
semanticscholar   +1 more source

A New Mixing of Hartree-Fock and Local Density-Functional Theories

, 1993
Previous attempts to combine Hartree–Fock theory with local density‐functional theory have been unsuccessful in applications to molecular bonding. We derive a new coupling of these two theories that maintains their simplicity and computational efficiency,
A. Becke
semanticscholar   +1 more source

Density-functional approximation for the correlation energy of the inhomogeneous electron gas.

Physical Review B (Condensed Matter), 1986
Langreth and Mehl (LM) and co-workers have developed a useful spin-density functional for the correlation energy of an electronic system. Here the LM functional is improved in two ways: (1) The natural separation between exchange and correlation is made,
J. Perdew
semanticscholar   +1 more source

Multivariate Density Estimation, Theory, Practice and Visualization

, 1992
Representation and Geometry of Multivariate Data. Nonparametric Estimation Criteria. Histograms: Theory and Practice. Frequency Polygons. Averaged Shifted Histograms. Kernel Density Estimators.
D. W. Scott
semanticscholar   +1 more source

Estimating densities, quantiles, quantile densities and density quantiles

Annals of the Institute of Statistical Mathematics, 1992
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
openaire   +3 more sources

Design of capacity-approaching irregular low-density parity-check codes

IEEE Transactions on Information Theory, 2001
We design low-density parity-check (LDPC) codes that perform at rates extremely close to the Shannon capacity. The codes are built from highly irregular bipartite graphs with carefully chosen degree patterns on both sides. Our theoretical analysis of the
T. Richardson, A. Shokrollahi, R. Urbanke   +2 more
semanticscholar   +1 more source

The densities and limiting densities of vapours

Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1951
By means of a new type of microbalance working in conjunction with a multiple-point manometer, an accurate comparison of the balancing pressures at the same density of oxygen and benzene vapour has been made at 22° C and in the region of from 19 to 69 mm. of benzene pressure.
F. L. Casado, Doreen S. Massie, R. Whytlaw-Gray   +2 more
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