42,662 research outputs found
Semi-Classical Description of Antiproton Capture on Atomic Helium
A semi-classical, many-body atomic model incorporating a momentum-dependent
Heisenberg core to stabilize atomic electrons is used to study antiproton
capture on Helium. Details of the antiproton collisions leading to eventual
capture are presented, including the energy and angular momentum states of
incident antiprotons which result in capture via single or double electron
ionization, i.e. into [He or He], and the
distribution of energy and angular momentum states following the Auger cascade.
These final states are discussed in light of recently reported, anomalously
long-lived antiproton states observed in liquid He.Comment: 15 pages, 9 figures may be obtained from authors, Revte
Alternator and voltage regulator-exciter for a Brayton cycle space power system. Volume 2 - Unbalanced electromagnetic forces
Unbalanced electromagnetic forces in Brayton cycle turboalternator for space power syste
Stochastic transport in the presence of spatial disorder: fluctuation-induced corrections to homogenization
Motivated by uncertainty quantification in natural transport systems, we
investigate an individual-based transport process involving particles
undergoing a random walk along a line of point sinks whose strengths are
themselves independent random variables. We assume particles are removed from
the system via first-order kinetics. We analyse the system using a hierarchy of
approaches when the sinks are sparsely distributed, including a stochastic
homogenization approximation that yields explicit predictions for the extrinsic
disorder in the stationary state due to sink strength fluctuations. The
extrinsic noise induces long-range spatial correlations in the particle
concentration, unlike fluctuations due to the intrinsic noise alone.
Additionally, the mean concentration profile, averaged over both intrinsic and
extrinsic noise, is elevated compared with the corresponding profile from a
uniform sink distribution, showing that the classical homogenization
approximation can be a biased estimator of the true mean.Comment: 16 pages, 8 figure
Design mobile satellite system architecture as an integral part of the cellular access digital network
The Cellular Access Digital Network (CADN) is the access vehicle through which cellular technology is brought into the mainstream of the evolving integrated telecommunications network. Beyond the integrated end-to-end digital access and per call network services provisioning of the Integrated Services Digital Network (ISDN), the CADN engenders the added capability of mobility freedom via wireless access. One key element of the CADN network architecture is the standard user to network interface that is independent of RF transmission technology. Since the Mobile Satellite System (MSS) is envisioned to not only complement but also enhance the capabilities of the terrestrial cellular telecommunications network, compatibility and interoperability between terrestrial cellular and mobile satellite systems are vitally important to provide an integrated moving telecommunications network of the future. From a network standpoint, there exist very strong commonalities between the terrestrial cellular system and the mobile satellite system. Therefore, the MSS architecture should be designed as an integral part of the CADN. This paper describes the concept of the CADN, the functional architecture of the MSS, and the user-network interface signaling protocols
OGO-3 observations of ELF noise in the magnetosphere - Part 1 - Spatial extent and frequency of occurrence
OGO-3 spectrum analyzer measurements of magnetic noise in magnetospher
The Kauffman Index: Startup Activity National Trends - 2016
This report provides a broad index measure of business startup activity in the United States. It is an equally weighted index of three normalized measures of startup activity:The Rate of New Entrepreneurs in the economy, calculated as the percentage of adults becoming entrepreneurs in a given month.The Opportunity Share of New Entrepreneurs, calculated as the percentage of new entrepreneurs driven primarily by "opportunity" vs. "necessity."The Startup Density of a region, measured as the number of new employer businesses normalized by total business population
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