3,766 research outputs found
Plasma chemistry and its applications
The relationship between discharge phenomena and plasma chemistry, as well as the equipment and mechanisms of plasma chemical reactions are described. Various areas in which plasma chemistry is applied are surveyed, such as: manufacturing of semiconductor integrated circuits; synthetic fibers; high polymer materials for medical uses; optical lenses; and membrane filters (reverse penetration films)
Development of multiple tidal tails around globular clusters and dwarf satellite galaxies
The formation and evolution of tidal tails like those observed around some
globular clusters and dwarf satellite galaxies is examined with an N-body
simulation. In particular, we analyse in detail the evolving tidal features of
a one-component satellite that is moving on a highly eccentric orbit in the
external field of a host galaxy potential like our own. The results show that
every time the satellite approaches apogalacticon, a fresh pair of tidal tails
becomes notably prominent, and that eventually, the satellite possesses
multiple tidal tails via repeating apocentre passages. Accordingly, the number
of observed tidal arms can be used as a tracer of the number of orbital periods
that such a system has completed around the centre of its host galaxy. By
identifying the arm particles included in each of the first three consecutively
formed pairs of tidal tails, we find that each pair of tidal tails is
practically identical to one another regarding the energy and angular-momentum
distributions. In addition, we demonstrate that the density profiles of these
three pairs of tidal tails at their first apogalacticons after formation agree
well with one another. It therefore follows that the multiplicity in tidal
features originates from the repeated episode of tidal-arm formation in the
course of the precessing motion of a satellite.Comment: 11 pages, 17 figures, accepted for publication in MNRA
Highlights of 10th plasma chemistry meeting
The chemical structure is given of a film formed by plasma polymerization from pyridine monomers. The film has a hydrophilic chemical structure, its molecular weight is 900, and the molecular system is C55H50N10O3. The electrical characteristics of a plasma polymerized film are described. The film has good insulating properties and was successfully applied as video disc coating. Etching resistance properties make it possible to use the film as a resist in etching. The characteristics of plasma polymer formed from monomers containing tetramethyltin are discussed. The polymer is in film form, displays good adhesiveness, is similar to UV film UV 35 in light absorption and is highly insulating
Hydrophobic coating of solid materials by plasma-polymerized thin film using tetrafluoroethylene
Glass slides were coated with plasma-polymerized tetrafluoroethylene films of different thickness using the glow discharge technique in a tube-shaped chamber, and the plasma conditions, film growth rates, light permeability of the polymer films, and particle bond strength in the polymer films were studied. Ashed sections of mouse organs and ashed bacillus spores were also coated to give them hydrophobic treatment without damaging their shapes or appearance. The hydrophobic coating of the specimens was successful, and the fine ash patterns were strongly fixed onto the glass slides, making permanent preparations
Selective Sampling for Example-based Word Sense Disambiguation
This paper proposes an efficient example sampling method for example-based
word sense disambiguation systems. To construct a database of practical size, a
considerable overhead for manual sense disambiguation (overhead for
supervision) is required. In addition, the time complexity of searching a
large-sized database poses a considerable problem (overhead for search). To
counter these problems, our method selectively samples a smaller-sized
effective subset from a given example set for use in word sense disambiguation.
Our method is characterized by the reliance on the notion of training utility:
the degree to which each example is informative for future example sampling
when used for the training of the system. The system progressively collects
examples by selecting those with greatest utility. The paper reports the
effectiveness of our method through experiments on about one thousand
sentences. Compared to experiments with other example sampling methods, our
method reduced both the overhead for supervision and the overhead for search,
without the degeneration of the performance of the system.Comment: 25 pages, 14 Postscript figure
Time evolution of galactic warps in prolate haloes
A recent observation with the Hipparcos satellite and some numerical
simulations imply that the interaction between an oblate halo and a disc is
inappropriate for the persistence of galactic warps. Then, we have compared the
time evolution of galactic warps in a prolate halo with that in an oblate halo.
The haloes were approximated as fixed potentials, while the discs were
represented by N-body particles. We have found that the warping in the oblate
halo continues to wind up, and finally disappears. On the other hand, for the
prolate halo model, the precession rate of the outer disc increases when the
precession of the outer disc recedes from that of the inner disc, and vice
versa. Consequently, the warping in the prolate halo persisted to the end of
the simulation by retaining the alignment of the line of nodes of the warped
disc. Therefore, our results suggest that prolate haloes could sustain galactic
warps. The physical mechanism of the persistence of warp is discussed on the
basis of the torque between a halo and a disc and that between the inner and
outer regions of the disc.Comment: 8 pages, 8 figures. Accepted for publication in MNRA
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