6,998 research outputs found
Cesium iodide crystals fused to vacuum tube faceplates
A cesium iodide crystal is fused to the lithium fluoride faceplate of a photon scintillator image tube. The conventional silver chloride solder is then used to attach the faceplate to the metal support
ARCHITECTURE OF A MODERN PROCESSING OSCILLOSCOPE
For many applications the functions of a voltmeter, counter, power meter etc. can be
provided by a single measurement instrument, the digitizing processing oscilloscope. An
instrument featuring these capabilities has to be designed with respect to high speed data
transfers and simultaneous calculation of processed waveforms as well as scalar measure-
ment functions. This paper describes the architecture of a recently introduced modern
processing oscilloscope which is able to perform algebraic and analytical processing on
time domain signals as well as various amplitude or time measurements
Phase Behavior of Polyelectrolyte-Surfactant Complexes at Planar Surfaces
We investigate theoretically the phase diagram of an insoluble charged
surfactant monolayer in contact with a semi-dilute polyelectrolyte solution (of
opposite charge). The polyelectrolytes are assumed to have long-range and
attractive (electrostatic) interaction with the surfactant molecules. In
addition, we introduce a short-range (chemical) interaction which is either
attractive or repulsive. The surfactant monolayer can have a lateral phase
separation between dilute and condensed phases. Three different regimes of the
coupled system are investigated depending on system parameters. A regime where
the polyelectrolyte is depleted due to short range repulsion from the surface,
and two adsorption regimes, one being dominated by electrostatics, whereas the
other by short range chemical attraction (similar to neutral polymers). When
the polyelectrolyte is more attracted (or at least less repelled) by the
surfactant molecules as compared with the bare water/air interface, it will
shift upwards the surfactant critical temperature. For repulsive short-range
interactions the effect is opposite. Finally, the addition of salt to the
solution is found to increase the critical temperature for attractive surfaces,
but does not show any significant effect for repulsive surfaces.Comment: 23 pages, 10 figure
Canonical Quantization of the Maxwell-Chern-Simons Theory in the Coulomb Gauge
The Maxwell-Chern-Simons theory is canonically quantized in the Coulomb gauge
by using the Dirac bracket quantization procedure. The determination of the
Coulomb gauge polarization vector turns out to be intrincate. A set of quantum
Poincar\'e densities obeying the Dirac-Schwinger algebra, and, therefore, free
of anomalies, is constructed. The peculiar analytical structure of the
polarization vector is shown to be at the root for the existence of spin of the
massive gauge quanta.The Coulomb gauge Feynman rules are used to compute the
M\"oller scattering amplitude in the lowest order of perturbation theory. The
result coincides with that obtained by using covariant Feynman rules. This
proof of equivalence is, afterwards, extended to all orders of perturbation
theory. The so called infrared safe photon propagator emerges as an effective
propagator which allows for replacing all the terms in the interaction
Hamiltonian of the Coulomb gauge by the standard field-current minimal
interaction Hamiltonian.Comment: 21 pages, typeset in REVTEX, figures not include
Spectroscopy of doubly charmed baryons
We study the mass spectrum of baryons with two and three charmed quarks. For
double charm baryons the spin splitting is found to be smaller than standard
quark-model potential predictions. This splitting is not influenced either by
the particular form of the confining potential or by the regularization taken
for the contact term of the spin-spin potential. We consistently predict the
spectra for triply charmed baryons.Comment: 6 pages, 1 figure, accepted for publication in Phys. Rev.
The responses of central octavolateralis cells to moving sources
MĂĽller HM, Fleck A, Bleckmann H. The responses of central octavolateralis cells to moving sources. Journal of Comparative Physiology A. 1996;179:455-471
Quantum signatures in laser-driven relativistic multiple-scattering
The dynamics of an electronic Dirac wave packet evolving under the influence
of an ultra-intense laser pulse and an ensemble of highly charged ions is
investigated numerically. Special emphasis is placed on the evolution of
quantum signatures from single to multiple scattering events. We quantify the
occurrence of quantum relativistic interference fringes in various situations
and stress their significance in multiple-particle systems, even in the
relativistic range of laser-matter interaction.Comment: 4 pages, 2 figures, LaTeX, revtex
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