2,943 research outputs found
New brazing alloy eliminates metal-stress cracking
Silver 15 zinc brazing alloy avoids the liquid- metal stress cracking of base metals when applied to 347, 316, and 410 stainless steels and certain other alloys
Energetic and magnetosheath energy particle signatures of the low-latitude boundary layer at low altitudes near noon
The low-latitude boundary layer (LBL) and its separation from the cusp have previously been identified using observations of particle precipitation at magnetosheath energies. Using S3-3 satellite observations, we have determined that these identifications can also be made from energetic particle observations on polar-orbiting satellites. It is found that the equatorward boundary of the LBL is identifiable as an approximately discontinuous decrease in 33-keV electron fluxes from low to high latitudes. Both the energetic ion and electron fluxes decrease discontinuously at the boundary between the LBL and the cusp or polar cap. A distinct LBL is nearly always identifiable in energetic particle measurements in the 10-14 MLT region when counting rates are statistically significant. The identifications obtained using the energetic particle measurements have been compared to those obtained using criteria developed by Newell and Meng (1988, 1989) for magnetosheath energy particle precipitation. In this way, we have evaluated the accuracy of both techniques and used the energetic particle measurements to supplement the identifications obtained using the Newell and Meng criteria. We propose that the Newell and Meng threshold on ion energy flux can be reduced by a factor of 6. This modification provides identification of the LBL for lower ion intensity levels than has previously been thought possible. Source, acceleration, and scattering processes have also been studied within and in the vicinity of the LBL. Observed trapped pitch angle distributions of energetic electrons imply that the LBL is at least partially on closed field lines. Strong scattering of energetic protons is found within and equatorward of the LBL and thus must occur at least partially along closed field lines. Field-aligned electron acceleration by parallel electric fields can be discerned within and poleward of the LBL, but a more detailed analysis is necessary for a statistical study. Conical ion acceleration was seen relatively frequently within the LBL and about half as often poleward of the LBL. Neither acceleration process could be identified anywhere equatorward of the LBL
Electron-Phonon Driven Spin Frustration in Multi-Band Hubbard Models: MX Chains and Oxide Superconductors
We discuss the consequences of both electron-phonon and electron-electron
couplings in 1D and 2D multi-band (Peierls-Hubbard) models. After briefly
discussing various analytic limits, we focus on (Hartree-Fock and exact)
numerical studies in the intermediate regime for both couplings, where unusual
spin-Peierls as well as long-period, frustrated ground states are found. Doping
into such phases or near the phase boundaries can lead to further interesting
phenomena such as separation of spin and charge, a dopant-induced phase
transition of the global (parent) phase, or real-space (``bipolaronic'')
pairing. We discuss possible experimentally observable consequences of this
rich phase diagram for halogen-bridged, transition metal, linear chain
complexes (MX chains) in 1D and the oxide superconductors in 2D.Comment: 6 pages, four postscript figures (appended), in regular Te
Anger Expression, Emotion Regulation and Mindfulness as Predictors of Conduct Problems in Children
Conduct problems and aggressive behaviors of children are serious problems for peers, parents and teachers of these children. To improve the understanding of conduct problems the present study investigates the links between difficulties in anger expression, emotion regulation, difficulties in impulse control and conduct problems. Moreover the relation of mindfulness and emotion regulation was of interest in the present study. To answer our research questions 310 elementary school children (157 boys, 153 girls) and their parents reported anger expression, emotion regulation strategies, mindfulness and conduct problems in a questionnaire. The results revealed that mindfulness was significantly related to anger expression and conduct problems. Moreover a regression analysis showed that anger expression mediated the relation of mindfulness and conduct problems. Child and parent reports were only weakly related if anger expression strategies that are hardly observable (Anger In, Anger Control) were considered. Relations were somewhat stronger for Anger Out. The findings are discussed and the relevance of mindfulness based emotion regulation is highlighted. The findings support the assumption that mindfulness, anger expression and emotion regulation are important aspects that influence child behavior
Batrachospermum Roth. (Rhodophyta), a genus of red algae new to Iowa
Batrachospermum, a floridean red alga, is formally reported from Iowa. Populations have been observed by several workers at nine localities in eight counties: Black Hawk, Bremer, Des Moines, Dickinson, Dubuque, Emmet, Hancock, and Webster. The habitats include permanent and intermittent streams, a distrophic lake, and prairie marshes. To date, the species include B. ectocarpum Sir. from a stream in Webster County , and an undescribed species from a prairie marsh in Black Hawk County. A discussion of the taxonomy and occurrence of Batrachospermum in Iowa in presented. With this report, four genera of freshwater red algae are known from Iowa
Complex perspective for the projective heat map acting on pentagons
We place Schwartz's work on the real dynamics of the projective heat map H
into the complex perspective by computing its rst dynamical degree and gleaning some
corollaries about the dynamics of H
Superstable manifolds of invariant circles and codimension-one Böttcher functions
Let f : X ⇢ X be a dominant meromorphic self-map, where X is a compact, connected complex manifold of dimension n>1. Suppose that there is an embedded copy of P1 that is invariant under f, with f holomorphic and transversally superattracting with degree a in some neighborhood. Suppose that f restricted to this line is given by z↦zb, with resulting invariant circle S. We prove that if a≥b, then the local stable manifold Wsloc(S) is real analytic. In fact, we state and prove a suitable localized version that can be useful in wider contexts. We then show that the condition a≥b cannot be relaxed without adding additional hypotheses by presenting two examples with a<b for which Wsloc(S) is not real analytic in the neighborhood of any point
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