1,125 research outputs found
Corrosion of uranium in liquid water under contained conditions with a headspace deuterium overpressure. Part 2:The ternary U + H <sub>2</sub> O <sub>(l)</sub> + D <sub>2</sub> system
Corrosion of uranium in liquid water under vacuum contained conditions. Part 1:The initial binary U + H <sub>2</sub> O <sub>(l)</sub> system
Oscillatory behaviour in a lattice prey-predator system
Using Monte Carlo simulations we study a lattice model of a prey-predator
system. We show that in the three-dimensional model populations of preys and
predators exhibit coherent periodic oscillations but such a behaviour is absent
in lower-dimensional models. Finite-size analysis indicate that amplitude of
these oscillations is finite even in the thermodynamic limit. In our opinion,
this is the first example of a microscopic model with stochastic dynamics which
exhibits oscillatory behaviour without any external driving force. We suggest
that oscillations in our model are induced by some kind of stochastic
resonance.Comment: 7 pages, 10 figures, Phys.Rev.E (Nov. 1999
Mesoscopic Behavior Near a Two-Dimensional Metal-Insulator Transition
We study conductance fluctuations in a two-dimensional electron gas as a
function of chemical potential (or gate voltage) from the strongly insulating
to the metallic regime. Power spectra of the fluctuations decay with two
distinct exponents (1/v_l and 1/v_h). For conductivity , we find a third exponent (1/v_i) in the shortest samples, and
non-monotonic dependence of v_i and v_l on \sigma. We study the dependence of
v_i, v_l, v_h, and the variances of corresponding fluctuations on \sigma,
sample size, and temperature. The anomalies near
indicate that the dielectric response and screening length are critically
behaved, i.e. that Coulomb correlations dominate the physics.Comment: Revised according to referee remark
Exploring the psychological rewards of a familiar semirural landscape: connecting to local nature through a mindful approach
This study analyses a 53,000 word diary of a year engaging with nature through over 200 trips to a semi-rural landscape. Thematic analysis revealed two themes; the transition from observer to nature connectedness and the ways in which the natural environment was experienced once a connection was made. These themes are discussed in relation to theories that seek to explain the positive effect of nature and nature connectedness. The findings are important as they suggest that repeated engagement with local semi-rural countryside can lead to a mindful approach and psychological rewards that do not require travel into the wilderness. The work informs further research into outcomes and processes of nature based interventions such as: trip frequency, duration and diary keeping
Molecular phases in coupled quantum dots
We present excitation energy spectra of few-electron vertically coupled
quantum dots for strong and intermediate inter-dot coupling. By applying a
magnetic field, we induce ground state transitions and identify the
corresponding quantum numbers by comparison with few-body calculations. In
addition to atomic-like states, we find novel "molecular-like" phases. The
isospin index characterizes the nature of the bond of the artificial molecule
and this we control. Like spin in a single quantum dot, transitions in isospin
leading to full polarization are observed with increasing magnetic field.Comment: PDF file only, 28 pages, 3 tables, 4 color figures, 2 appendices. To
appear in Physical Review B, Scheduled 15 Feb 2004, Vol. 69, Issue
In-beam internal conversion electron spectroscopy with the SPICE detector
The SPectrometer for Internal Conversion Electrons (SPICE) has been
commissioned for use in conjunction with the TIGRESS -ray spectrometer
at TRIUMF's ISAC-II facility. SPICE features a permanent rare-earth magnetic
lens to collect and direct internal conversion electrons emitted from nuclear
reactions to a thick, highly segmented, lithium-drifted silicon detector. This
arrangement, combined with TIGRESS, enables in-beam -ray and internal
conversion electron spectroscopy to be performed with stable and radioactive
ion beams. Technical aspects of the device, capabilities, and initial
performance are presented
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