15,652 research outputs found
Feasibility study to determine methods of measuring the temperature of a molecular beam Final report
Molecular beam sampling technique for temperature measurement of earth thermospher
Development of an accurate wide range ultra high vacuum gauge calibration method
Accurate wide range ultrahigh vacuum gauge calibration method using pressure attenuation, atomic beam, and cryopumping techniques to evaluate system components and performanc
Development of an accurate wide range ultra high vacuum gauge calibration method, 29 June 1966 - 28 February 1968
Calibration method and ultrahigh vacuum components for ionization gage and mass spectromete
A cold cathode ion source mass spectrometer employing ion counting techniques
Design and construction of mass spectrometer using cold cathode source of ions, quadrupole mass analyzer, and ion counting detector
Conservação das sementes de Pinheiro-do-Paraná (Araucaria angustifolia Bert.O.Ktze.)
Edição dos resumos do 18º Congresso Brasileiro de Sementes, 2013, Florianópolis. CD-ROM
Investigation of electro-optical techniques for controlling the direction of a laser beam. Part one - Beam deflector devices. Part two - Beam deflector systems Interim report
Piezoelectrically powered laser beam waveguide for electro-optical acquisition and trackin
On a Tree and a Path with no Geometric Simultaneous Embedding
Two graphs and admit a geometric simultaneous
embedding if there exists a set of points P and a bijection M: P -> V that
induce planar straight-line embeddings both for and for . While it
is known that two caterpillars always admit a geometric simultaneous embedding
and that two trees not always admit one, the question about a tree and a path
is still open and is often regarded as the most prominent open problem in this
area. We answer this question in the negative by providing a counterexample.
Additionally, since the counterexample uses disjoint edge sets for the two
graphs, we also negatively answer another open question, that is, whether it is
possible to simultaneously embed two edge-disjoint trees. As a final result, we
study the same problem when some constraints on the tree are imposed. Namely,
we show that a tree of depth 2 and a path always admit a geometric simultaneous
embedding. In fact, such a strong constraint is not so far from closing the gap
with the instances not admitting any solution, as the tree used in our
counterexample has depth 4.Comment: 42 pages, 33 figure
On the Nature of Precursors in the Radio Pulsar Profiles
In the average profiles of several radio pulsars, the main pulse is
accompanied by the preceding component. This so called precursor is known for
its distinctive polarization, spectral, and fluctuation properties. Recent
single-pulse observations hint that the sporadic activity at the extreme
leading edge of the pulse may be prevalent in pulsars. We for the first time
propose a physical mechanism of this phenomenon. It is based on the induced
scattering of the main pulse radiation into the background. We show that the
scattered component is directed approximately along the ambient magnetic field
and, because of rotational aberration in the scattering region, appears in the
pulse profile as a precursor to the main pulse. Our model naturally explains
high linear polarization of the precursor emission, its spectral and
fluctuation peculiarities as well as suggests a specific connection between the
precursor and the main pulse at widely spaced frequencies. This is believed to
stimulate multifrequency single-pulse studies of intensity modulation in
different pulsars.Comment: 5 pages, no figures. Accepted for publication in MNRAS Letter
Lattice-Gas Simulations of Ternary Amphiphilic Fluid Flow in Porous Media
We develop our existing two-dimensional lattice-gas model to simulate the
flow of single-phase, binary-immiscible and ternary-amphiphilic fluids. This
involves the inclusion of fixed obstacles on the lattice, together with the
inclusion of ``no-slip'' boundary conditions. Here we report on preliminary
applications of this model to the flow of such fluids within model porous
media. We also construct fluid invasion boundary conditions, and the effects of
invading aqueous solutions of surfactant on oil-saturated rock during
imbibition and drainage are described.Comment: 9 pages, 6 figures (1 and 6 are in color), RevTeX with epsf and
graphic
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