15,273 research outputs found
Ammonia adsorption and decomposition on a tungsten /211/ surface
Ammonia adsorption and decomposition on tungsten 211 surface studied by mass spectrometry, electron diffraction, and changes in work functio
First steps in the oxidation of a /110/ nickel surface
Initial steps in oxidation of nickel surface studied using low energy back-reflection electron diffractio
Electron beam chemistry produces high purity metals
Application of radiation chemistry for deposition of metals by irradiation of aqueous solutions with high energy electrons is presented. Design of reaction vessel for irradiation of solution is illustrated. Features of radiochemical technique and procedures followed are described
The application of semiconductors to quasi- optical isolators for use at submillimeter wavelengths
Semiconductor application to quasi-optical isolators - nonreciprocal reflection beam isolator and far infrared isolators using Faraday rotatio
Robust Emergent Activity in Dynamical Networks
We study the evolution of a random weighted network with complex nonlinear
dynamics at each node, whose activity may cease as a result of interactions
with other nodes. Starting from a knowledge of the micro-level behaviour at
each node, we develop a macroscopic description of the system in terms of the
statistical features of the subnetwork of active nodes. We find the asymptotic
characteristics of this subnetwork to be remarkably robust: the size of the
active set is independent of the total number of nodes in the network, and the
average degree of the active nodes is independent of both the network size and
its connectivity. These results suggest that very different networks evolve to
active subnetworks with the same characteristic features. This has strong
implications for dynamical networks observed in the natural world, notably the
existence of a characteristic range of links per species across ecological
systems.Comment: 4 pages, 5 figure
Species Abundance Patterns in Complex Evolutionary Dynamics
An analytic theory of species abundance patterns (SAPs) in biological
networks is presented. The theory is based on multispecies replicator dynamics
equivalent to the Lotka-Volterra equation, with diverse interspecies
interactions. Various SAPs observed in nature are derived from a single
parameter. The abundance distribution is formed like a widely observed
left-skewed lognormal distribution. As the model has a general form, the result
can be applied to similar patterns in other complex biological networks, e.g.
gene expression.Comment: 4 pages, 3 figures. Physical Review Letters, in pres
Altruistic Contents of Quantum Prisoner's Dilemma
We examine the classical contents of quantum games. It is shown that a
quantum strategy can be interpreted as a classical strategies with effective
density-dependent game matrices composed of transposed matrix elements. In
particular, successful quantum strategies in dilemma games are interpreted in
terms of a symmetrized game matrix that corresponds to an altruistic game plan.Comment: Revised according to publisher's request: 4 pgs, 2 fgs, ReVTeX4. For
more info, go to http://www.mech.kochi-tech.ac.jp/cheon
IR optical fiber-based noncontact pyrometer for drop tube instrumentation
The design of a two color pyrometer with infrared optical fiber bundles for collection of the infrared radiation is described. The pyrometer design is engineered to facilitate its use for measurement of the temperature of small, falling samples in a microgravity materials processing experiment using a 100 meter long drop tube. Because the samples are small and move rapidly through the field of view of the pyrometer, the optical power budget of the detection system is severly limited. Strategies for overcoming this limitation are discussed
Three-dimensional simulations of laser-plasma interactions at ultrahigh intensities
Three-dimensional (3D) particle-in-cell (PIC) simulations are used to
investigate the interaction of ultrahigh intensity lasers (
W/cm) with matter at overcritical densities. Intense laser pulses are
shown to penetrate up to relativistic critical density levels and to be
strongly self-focused during this process. The heat flux of the accelerated
electrons is observed to have an annular structure when the laser is tightly
focused, showing that a large fraction of fast electrons is accelerated at an
angle. These results shed light into the multi-dimensional effects present in
laser-plasma interactions of relevance to fast ignition of fusion targets and
laser-driven ion acceleration in plasmas.Comment: 2 pages, 1 figur
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