10,601 research outputs found
The applicability of MFD thrusters to satellite power systems
The high power self field MPD thruster uses electromagnetic forces rather than electrostatic to accelerate a neutral plasma. The most attractive application of MPD thrusters to satellite power systems is in the area of electric propulsion for a cargo orbit transfer vehicle (COTV). Calculations were performed in order to compare the performance of a COTV using an ion or MPD propulsion system. Results show that the MPD propulsion system gives a shorter trip time with the same power and payload when compared to the ion thruster propulsion system at either value of specific impulse. More important than the trip time benefit may be the advantage a MPD propulsion system provides in system simplicity. Another interesting COTV concept using MPD thrusters is the use of a remote power supply located on the Earth, at GEO, or somewhere in between to transmit power to the COTV in a microwave transmission. The specific impulse at thrust levels of tens of newtons makes a MPD propulsion system a candidate for stationkeeping and attitude control of large space structures such as a SPS
The Limits of Judicial Review in Constitutional Adjudication
Constitutional adjudication presently requires that in order for a party to challenge a governmental act he must claim that the act has violated his constitutional rights. The purpose of this article is to show that such a requirement undermines constitutional limits on governmental actions and is inconsistent with a proper interpretation of the Constitution.
I. Introduction
II. The Police Power
III. The Government Operations Power
IV. The Law Declaration Power
V. Conclusio
Plume Characterization of a One-Millipound Solid Teflon Pulsed Plasma Thruster, Phase 2
Measurements of the pulsed plasma thruster (PPT) plume upstream mass flux were made in the Molecular Sink (MOLSINK) vacuum facility in order to minimize the plume-tank wall reflected mass flux. Using specially designed collimators on 4 rows of Quartz Crystal Microbalanced (QCMs) mounted on a support extending radially away from the plume axis, measurements were made of the mass flux originating in a thin slice of the PPT primary plume at an arbitrary dip angle with respect to the thruster axis. The measured and analytically corrected mass flux from particles reflected from the MOLSINK walls was substracted from the collimated QCM measurements to improve their accuracy. These data were then analytically summed over dip angle to estimate the total plume backflow upstream of the thruster nozzle. The results indicate that the PPT backflow is of order 10 to the minus 10th power g/square cm/pulse in the region from 38 to 86 cm from the PPT axis in the nozzle exit plane. This flux drops with the square of the radial distance from the PPT axis and is comparable to the backflow of an 8 cm ion thruster, which has performance characteristics similar to those of the PPT
Experimental Quantum Process Discrimination
Discrimination between unknown processes chosen from a finite set is
experimentally shown to be possible even in the case of non-orthogonal
processes. We demonstrate unambiguous deterministic quantum process
discrimination (QPD) of non-orthogonal processes using properties of
entanglement, additional known unitaries, or higher dimensional systems. Single
qubit measurement and unitary processes and multipartite unitaries (where the
unitary acts non-separably across two distant locations) acting on photons are
discriminated with a confidence of in all cases.Comment: 4 pages, 3 figures, comments welcome. Revised version includes
multi-partite QP
(2+1) resonant enhanced multiphoton ionization of H_2 via the E, F^(1)Σ^+_g state
In this paper, we report the results of ab initio calculations of photoelectron angular distributions and vibrational branching ratios for the (2+1) REMPI of H_2 via the E, F^(1)Σ^+_g state, and compare these with the experimental data of Anderson et al. [Chem. Phys. Lett. 105, 22 (1984)]. These results show that the observed non‐Franck–Condon behavior is predominantly due to the R dependence of the transition matrix elements, and to a lesser degree to the energy dependence. This work presents the first molecular REMPI study employing a correlated wave function to describe the Rydberg–valence mixing in the resonant intermediate state
A simple encoding of a quantum circuit amplitude as a matrix permanent
A simple construction is presented which allows computing the transition
amplitude of a quantum circuit to be encoded as computing the permanent of a
matrix which is of size proportional to the number of quantum gates in the
circuit. This opens up some interesting classical monte-carlo algorithms for
approximating quantum circuits.Comment: 6 figure
Investigations into the triggered lightning response of the F106B thunderstorm research aircraft
An investigation has been conducted into the lightning characteristics of the NASA F106B thunderstorm research aircraft. The investigation includes analysis of measured data from the aircraft in the time and frequency domains. Linear and nonlinear computer modelling has also been performed. In addition, new computer tools have been developed, including a new enhanced nonlinear air breakdown model, and a subgrid model useful for analyzing fine details of the aircraft's geometry. Comparison of measured and calculated electromagnetic responses of the aircraft to a triggered lightning environment are presented
Gauge Orbit Types for Theories with Classical Compact Gauge Group
We determine the orbit types of the action of the group of local gauge
transformations on the space of connections in a principal bundle with
structure group O(n), SO(n) or over a closed, simply connected manifold
of dimension 4. Complemented with earlier results on U(n) and SU(n) this
completes the classification of the orbit types for all classical compact gauge
groups over such space-time manifolds. On the way we derive the classification
of principal bundles with structure group SO(n) over these manifolds and the
Howe subgroups of SO(n).Comment: 57 page
Further results on the cross norm criterion for separability
In the present paper the cross norm criterion for separability of density
matrices is studied. In the first part of the paper we determine the value of
the greatest cross norm for Werner states, for isotropic states and for Bell
diagonal states. In the second part we show that the greatest cross norm
criterion induces a novel computable separability criterion for bipartite
systems. This new criterion is a necessary but in general not a sufficient
criterion for separability. It is shown, however, that for all pure states, for
Bell diagonal states, for Werner states in dimension d=2 and for isotropic
states in arbitrary dimensions the new criterion is necessary and sufficient.
Moreover, it is shown that for Werner states in higher dimensions (d greater
than 2), the new criterion is only necessary.Comment: REVTeX, 19 page
Particle alignments and shape change in Ge and Ge
The structure of the nuclei Ge and Ge is studied
by the shell model on a spherical basis. The calculations with an extended
Hamiltonian in the configuration space
(, , , ) succeed in reproducing
experimental energy levels, moments of inertia and moments in Ge isotopes.
Using the reliable wave functions, this paper investigates particle alignments
and nuclear shapes in Ge and Ge.
It is shown that structural changes in the four sequences of the positive-
and negative-parity yrast states with even and odd are caused by
various types of particle alignments in the orbit.
The nuclear shape is investigated by calculating spectroscopic moments of
the first and second states, and moreover the triaxiality is examined by
the constrained Hatree-Fock method.
The changes of the first band crossing and the nuclear deformation depending
on the neutron number are discussed.Comment: 18 pages, 21 figures; submitted to Phys. Rev.
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