105,097 research outputs found
Germanium:gallium photoconductors for far infrared heterodyne detection
Highly compensated Ge:Ga photoconductors have been fabricated and evaluated for high bandwidth heterodyne detection. Bandwidths up to 60 MHz have been obtained with corresponding current responsivity of 0.01 A/W
Arresting woodland bird decline in Australian agricultural landscapes: potential application of the European agri-environment model
This paper considered the applicability of the European model of land stewardship payments, in particular its support for biodiversity conservation in agricultural landscapes, to an Australian context. More broadly, the research approach described in the paper may also be applied to assessing the suitability of overseas stewardship schemes to the provision of any ecoservice in
Australia, such as carbon sequestration and floodwater regulation
Cooperative ordering of gapped and gapless spin networks in CuFeGeO
The unusual magnetic properties of a novel low-dimensional quantum
ferrimagnet CuFeGeO are studied using bulk methods, neutron
diffraction and inelastic neutron scattering. It is shown that this material
can be described in terms of two low-dimensional quantum spin subsystems, one
gapped and the other gapless, characterized by two distinct energy scales.
Long-range magnetic ordering observed at low temperatures is a cooperative
phenomenon caused by weak coupling of these two spin networks.Comment: 4 pages, 4 figure
Gamma-Rays Produced in Cosmic-Ray Interactions and the TeV-band Spectrum of RX J1713.7-3946
We employ the Monte Carlo particle collision code DPMJET3.04 to determine the
multiplicity spectra of various secondary particles (in addition to 's)
with 's as the final decay state, that are produced in cosmic-ray
('s and 's) interactions with the interstellar medium. We derive an
easy-to-use -ray production matrix for cosmic rays with energies up to
about 10 PeV. This -ray production matrix is applied to the GeV excess
in diffuse Galactic -rays observed by EGRET, and we conclude the
non- decay components are insufficient to explain the GeV excess,
although they have contributed a different spectrum from the -decay
component. We also test the hypothesis that the TeV-band -ray emission
of the shell-type SNR RX J1713.7-3946 observed with HESS is caused by hadronic
cosmic rays which are accelerated by a cosmic-ray modified shock. By the
statistics, we find a continuously softening spectrum is strongly
preferred, in contrast to expectations. A hardening spectrum has about 1%
probability to explain the HESS data, but then only if a hard cutoff at 50-100
TeV is imposed on the particle spectrum.Comment: 3 pages; 4 figures; Contribution to the First GLAST Symposium,
Standord, 200
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