7,998 research outputs found
The bearable lightness of being
How are philosophical questions about what kinds of things there are to be understood and how are they to be answered? This paper defends broadly Fregean answers to these questions. Ontological categories-such as object, property, and relation-are explained in terms of a prior logical categorization of expressions, as singular terms, predicates of varying degree and level, etc. Questions about what kinds of object, property, etc., there are are, on this approach, reduce to questions about truth and logical form: for example, the question whether there are numbers is the question whether there are true atomic statements in which expressions function as singular terms which, if they have reference at all, stand for numbers, and the question whether there are properties of a given type is a question about whether there are meaningful predicates of an appropriate degree and level. This approach is defended against the objection that it must be wrong because makes what there depend on us or our language. Some problems confronting the Fregean approach-including Frege's notorious paradox of the concept horse-are addressed. It is argued that the approach results in a modest and sober deflationary understanding of ontological commitments
Flame zone of a composite propellant expanded by a laser source
Technique scales flame structure linearly with gas kinetic mean free path, which increases two to three orders of magnitude as pressure decreases like amount. Kinetic and transport time scales expand in proportion so that regression rates for laser-induced flames are two to three orders of magnitude slower
Composite solid propellant flame microstructure determination Annual report, 23 Jun. 1967 - 22 Jun. 1968
Composite solid propellant flame microstructure determination
The clustering and bias of radio-selected AGN and star-forming galaxies in the COSMOS field
Dark matter haloes in which galaxies reside are likely to have a significant
impact on their evolution. We investigate the link between dark matter haloes
and their constituent galaxies by measuring the angular two-point correlation
function of radio sources, using recently released 3 GHz imaging over $\sim 2 \
\mathrm{deg}^2z<1b = 1.5
^{+0.1}_{-0.2}z=0.62b = 2.1\pm 0.2b =
2.9 \pm 0.3b = 1.8^{+0.4}_{-0.5}z \sim 0.7M_{h} \sim 3-4
\times 10^{13}h^{-1}_{\odot}M_{h} \sim 1-2 \times
10^{13}h^{-1}_{\odot}z \ge 1z<1$.Comment: 20 pages, 10 figures, 1 table, accepted by MNRA
Monotonic properties of the shift and penetration factors
We study derivatives of the shift and penetration factors of collision theory
with respect to energy, angular momentum, and charge. Definitive results for
the signs of these derivatives are found for the repulsive Coulomb case. In
particular, we find that the derivative of the shift factor with respect to
energy is positive for the repulsive Coulomb case, a long anticipated but
heretofore unproven result. These results are closely connected to the
properties of the sum of squares of the regular and irregular Coulomb
functions; we also present investigations of this quantity.Comment: 13 pages, 1 figur
4He experiments can serve as a database for determining the three-nucleon force
We report on microscopic calculations for the 4He compound system in the
framework of the resonating group model employing realistic nucleon-nucleon and
three nucleon forces. The resulting scattering phase shifts are compared to
those of a comprehensive R-matrix analysis of all data in this system, which
are available in numerical form. The agreement between calculation and analysis
is in most cases very good. Adding three-nucleon forces yields in many cases
large effects. For a few cases the new agreement is striking. We relate some
differencies between calculation and analysis to specific data and discuss
neccessary experiments to clarify the situation. From the results we conclude
that the data of the 4He system might be well suited to determine the structure
of the three-nucleon force.Comment: title changed,note added, format of figures changed, appearance of
figures in black-and-white changed, Phys. Rev. C accepte
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