Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Space primitive

Started with a Hessian diagonal in the space of primitive internals usmg the recipe of Schlegel [39]. [Pg.2345]

There are several issues to consider when using ECP basis sets. The core potential may represent all but the outermost electrons. In other ECP sets, the outermost electrons and the last filled shell will be in the valence orbital space. Having more electrons in the core will speed the calculation, but results are more accurate if the —1 shell is outside of the core potential. Some ECP sets are designated as shape-consistent sets, which means that the shape of the atomic orbitals in the valence region matches that for all electron basis sets. ECP sets are usually named with an acronym that stands for the authors names or the location where it was developed. Some common core potential basis sets are listed below. The number of primitives given are those describing the valence region. [Pg.84]

The theory is initially presented in the context of small deformations in Section 5.2. A set of internal state variables are introduced as primitive quantities, collectively represented by the symbol k. Qualitative concepts of inelastic deformation are rendered into precise mathematical statements regarding an elastic range bounded by an elastic limit surface, a stress-strain relation, and an evolution equation for the internal state variables. While these qualitative ideas lead in a natural way to the formulation of an elastic limit surface in strain space, an elastic limit surface in stress space arises as a consequence. An assumption that the external work done in small closed cycles of deformation should be nonnegative leads to the existence of an elastic potential and a normality condition. [Pg.118]

Let us give a brief summary of the LSGF method. We will consider a system of N atoms somehow distributed on the underlying primitive lattice. We start with the notion that if we choose an unperturbed reference system which has an ideal periodicity by placing eciuivalent effective scatterers on the same underlying lattice, its Hamiltonian may be calculated in the reciprocal space. Corresponding unperturbed Green s... [Pg.115]

Mobile CA. These arc CA in which some (or all) lattice sites are free to move about the lattice. In effect, mobile CA are primitive models of mobile robots. Typically, their internal state space reflects some features of the local environment within which they are allowed to move and with which they are allowed to interact. An example of mobile CA used to model some aspects of military engagements is discussed in Chapter 12. [Pg.18]

P should also minimize distinction.s between conventionally distinct but atomic. primitives (such as space, mass, time, etc.). The vision is to take one more step along the metaphoric road remove jnan from the center of the universe —> remove all privileged frames of reference —> remove all absolutes —> remove all distinction between space and matter—r remove all distinction ( ) Start by eliminating the tacit assumption that whatever physics is self-organizing itself out of the soup of the current crop of physicists is the physics of this universe in short, go from a solipsistic phys-ics to a fundamentally relativistic physics, wherein even physics itself becomes a set (an infinite hierarchical set ) of self-consistent world-views rather than a prescribed set of exactly/uniquely prescribed laws operating independently of all observers. [Pg.704]

The person whose name is most closely associated with the periodic table is Dmitri Mendeleev (1836-1907), a Russian chemist. In writing a textbook of general chemistry, Mendeleev devoted separate chapters to families of elements with similar properties, including the alkali metals, the alkaline earth metals, and the halogens. Reflecting on the properties of these and other elements, he proposed in 1869 a primitive version of today s periodic table. Mendeleev shrewdly left empty spaces in his table for new elements yet to be discovered. Indeed, he predicted detailed properties for three such elements (scandium, gallium, and germanium). By 1886 all of these elements had been discovered and found to have properties very similar to those he had predicted. [Pg.33]

The structure of PuB,qq is not yet clear. A satisfactory indexing can be made for a primitive cubic cell with a = 23.42 A, but with 10 reflections not characteristic of space group Fm3c . ... [Pg.235]

Figure 6. The Bohr-Sommerfeld phase corrections t)(8, ) for k = 0, 1, and 2. The ratio r z,k)lK estimates of the error of primitive Bohr-Sommerfeld eigenvalues as a fraction of their local vibrational spacing. Figure 6. The Bohr-Sommerfeld phase corrections t)(8, ) for k = 0, 1, and 2. The ratio r z,k)lK estimates of the error of primitive Bohr-Sommerfeld eigenvalues as a fraction of their local vibrational spacing.
The region within which k is considered (—n/a first Brillouin zone. In the coordinate system of k space it is a polyhedron. The faces of the first Brillouin zone are oriented perpendicular to the directions from one atom to the equivalent atoms in the adjacent unit cells. The distance of a face from the origin of the k coordinate system is n/s, s being the distance between the atoms. The first Brillouin zone for a cubic-primitive crystal lattice is shown in Fig. 10.11 the symbols commonly given to certain points of the Brillouin zone are labeled. The Brillouin zone consists of a very large number of small cells, one for each electronic state. [Pg.99]

From the above properties it is evident that the set of operations t forms a group, J the space group of the crystal. If the translation operations are the primitive translations is r , ... [Pg.321]

The Fermi paradox relates to the question as to whether intelligent life exists somewhere in space. But of course ETI species would need to be able to make themselves known by means of technical signals for us to detect their existence. Let us, however, pose the question as to whether life itself, including the most primitive life forms, is really to be found somewhere else in the universe such systems, however small, would have to satisfy the conditions so far defined for the term life (see Sect. 1.4). [Pg.301]

What does all this mean in a practical way Certainly we have no intention of writing programs for all partially computable functions indeed time and space considerations do not allow execution of all partially computable functions. The functions actually computed form a very small subset of the primitive recursive functions. We do not know, however, whether they fall into a class for which partial correctness is partially decidable one suspects not. In any case, since we obtain our undecidability results for programs with very simple structure, there can be nothing in the structure of "real" programs which will allow us by and of itself to conclude that the properties of interest are at least partially decidable. [Pg.212]


See other pages where Space primitive is mentioned: [Pg.1374]    [Pg.2171]    [Pg.2344]    [Pg.2344]    [Pg.2348]    [Pg.2411]    [Pg.2547]    [Pg.171]    [Pg.162]    [Pg.137]    [Pg.95]    [Pg.41]    [Pg.296]    [Pg.162]    [Pg.310]    [Pg.3]    [Pg.631]    [Pg.643]    [Pg.742]    [Pg.746]    [Pg.754]    [Pg.262]    [Pg.332]    [Pg.228]    [Pg.92]    [Pg.12]    [Pg.254]    [Pg.424]    [Pg.116]    [Pg.42]    [Pg.23]    [Pg.23]    [Pg.33]    [Pg.314]    [Pg.320]    [Pg.408]    [Pg.485]    [Pg.44]   
See also in sourсe #XX -- [ Pg.63 ]




SEARCH



Primitives

© 2024 chempedia.info