6,134 research outputs found
The microprocessor-based synthesizer controller
Implementation and performance of the microprocessor-based controllers and Dana Digiphase Synthesizer (DCO) installed in the Deep Space Network exciter in the 64-meter and 34-meter subnets to support uplink tuning required for the Voyager-Saturn Encounter is discussed. Test data in tests conducted during the production of the controllers verified the design objective for phase control accuracy of 10 to the - 12 power cycles in eight hours during ramping. Tests conducted require a phase error between a theoretical calculated value and the actual phase of no greater than + or - 1 cycle. Tests included (1) a ramp over a period of eight hours using a ramp rate which covers the synthesizer tuning range (40-51 MHz) and (2) a ramp sequence using the maximum rate (+ or kHz/s) over the tuning range
Neutrino Physics: an Update
We update our recent didactic survey of neutrino physics, including new
results from the Sudbury Neutrino Observatory and KamLAND experiments, and
recent constraints from WMAP and other cosmological probes.Comment: latex; 19 pages; five figure
Mark 4A DSN receiver-exciter and transmitter subsystems
The present configuration of the Mark 4A DSN Receiver-Exciter and Transmitter Subsystems is described. Functional requirements and key characteristics are given to show the differences in the capabilities required by the Networks Consolidation task for combined High Earth Orbiter and Deep Space Network tracking support
Potential Theory on Trees, Graphs and Ahlfors Regular Metric Spaces
We investigate connections between potential theories on a Ahlfors-regular
metric space X, on a graph G associated with X, and on the tree T obtained by
removing the "horizontal edges" in G. Applications to the calculation of set
capacity are given.Comment: 45 pages; presentation improved based on referee comment
Neutrino Physics
The basic concepts of neutrino physics are presented at a level appropriate
for integration into elementary courses on quantum mechanics and/or modern
physics.Comment: Prepared for the American Journal of Physics; 50 pages; 11 figures
(10 included); late
From Hadrons to Nuclei: Crossing the Border
The study of nuclei predates by many years the theory of quantum
chromodynamics. More recently, effective field theories have been used in
nuclear physics to ``cross the border'' from QCD to a nuclear theory. We are
now entering the second decade of efforts to develop a perturbative theory of
nuclear interactions using effective field theory. This work describes the
current status of these efforts.Comment: 141 pages, 58 figs, latex. To appear in the Boris Ioffe Festschrift,
ed. by M. Shifman, World Scientifi
"Blue energy" from ion adsorption and electrode charging in sea- and river water
A huge amount of entropy is produced at places where fresh water and seawater
mix, for example at river mouths. This mixing process is a potentially enormous
source of sustainable energy, provided it is harnessed properly, for instance
by a cyclic charging and discharging process of porous electrodes immersed in
salt and fresh water, respectively [D. Brogioli, Phys. Rev. Lett. 103, 058501
(2009)]. Here we employ a modified Poisson-Boltzmann free-energy density
functional to calculate the ionic adsorption and desorption onto and from the
charged electrodes, from which the electric work of a cycle is deduced. We
propose optimal (most efficient) cycles for two given salt baths involving two
canonical and two grand-canonical (dis)charging paths, in analogy to the
well-known Carnot cycle for heat-to-work conversion from two heat baths
involving two isothermal and two adiabatic paths. We also suggest a slightly
modified cycle which can be applied in cases that the stream of fresh water is
limited.Comment: 7 Figure
Structure of the Algebra of Effective Observables in Quantum Mechanics
A subclass of dynamical semigroups induced by the interaction of a quantum
system with an environment is introduced. Such semigroups lead to the selection
of a stable subalgebra of effective observables. The structure of this
subalgebra is completely determined
Electric dipole rovibrational transitions in HD molecule
The rovibrational electric dipole transitions in the ground electronic state
of the HD molecule are studied. A simple, yet rigorous formula is derived for
the transition rates in terms of the electric dipole moment function ,
which is calculated in a wide range of . Our numerical results for
transition rates are in moderate agreement with experiments and previous
calculations, but are at least an order of magnitude more accurate.Comment: 7 pages, 1 figur
The Pure State Space of Quantum Mechanics as Hermitian Symmetric Space
The pure state space of Quantum Mechanics is investigated as Hermitian
Symmetric Kaehler manifold. The classical principles of Quantum Mechanics
(Quantum Superposition Principle, Heisenberg Uncertainty Principle, Quantum
Probability Principle) and Spectral Theory of observables are discussed in this
non linear geometrical context.Comment: 18 pages, no figure
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