Analysis of aperture-coupled microstrip antenna using thesegmentation method

The authors present an original analysis of an aperture-coupled microstrip antenna. The theory is based on the segmentation method, which considers the patch as a multiport network whose impedance matrix is deduced from a hybrid matrix, and the use of analytical expressions of the cavity admittance at the slot centre. The theory is presented for the first time, and the theoretical results are in good agreement with previous published measurements     

Contribution of listeners' approaching motion to auditory distance perception.

Of the several sources of acoustic information for distance perception, those arising from motion of the listener or sound source have received little attention. This motion-related information (recently called acoustic tau) is described, and experiments evaluating its utilization are presented. Accuracy and consistency at walking to the locations of briefly presented sounds were better when people listened while walking than while standing still. Manipulations of the sound to simulate shorter or longer target distances produced appropriate undershooting but not overshooting. The results indicate that people use motion-related acoustic information about distance to guide their locomotor actions, although they do not take full advantage of this information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Young children's (Homo sapiens) understanding of knowledge formation in themselves and others.

Three- and 4-yr-old children were tested for comprehension of knowledge formation. In Exp 1, 34 Ss watched as a surprise was hidden under 1 of 4 obscured cups. The experimenter then pointed to the cup. All children searched under the correct cup, but no 3-yr-olds (in contrast to most 4-yr-olds) could explain how they knew where to look. Ss then discriminated between simultaneous pointing by 2 adults, one who had hidden a surprise and one who had left the room before the surprise was hidden. Most 4-yr-olds (but no 3-yr-olds) showed clear discrimination between the adults. In Exp 2, 16 Ss were tested with procedures designed to make the source of their own knowledge more obvious, but this had no effect on performance. It is concluded that studies using very similar procedures with chimpanzees and rhesus macaques were measuring an ability (or inability) to understand how knowledge states form. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of aging on directional and absolute errors in visuospatial memory.

Studied memory for visuospatial arrays in 28 male and 34 female healthy dextral adults (aged 20–90 yrs). 10 abstract figures were presented in each hemispace over a series of learning trials, and then delayed free recall of figure placement was obtained. Figures were misplaced significantly downward and leftward in both hemispaces. Both vertical and horizontal absolute error increased significanty with age, but no age effects on directional errors were observed. The increase in absolute error over age is consistent with decreased anterograde memory and visuospatial skills in the elderly. The directional errors are believed to result from an attentional shift toward proximal peripersonal space, in combination with attentional shifts from differential left vs right cerebral activation. Gender effects were also observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performance evaluation of dynamically linearized and kinematically redundant planar manipulators

The objective of this research is to investigate the feasibility of a theoretical development which could lead to advanced manipulator concepts offering fast dynamic and control features. Specifically, the application of “dynamic linearization” to a kinematically redundant planar manipulator is studied. In comparing such a manipulator with a standard non-linear, non-redundant design it is shown that in addition to the expected merits in linearity, dexterity, and computational simplicity, savings in actuator energy consumption can also be realized using a relative simple trajectory optimization scheme.     

The nuclear fuel cycle

In the first half of the 21st century, a redistribution of the energy data should occur, where nuclear will play a more important role, particularly as coal will become more and more costly to extract.On a worldwide basis, the unability of oil to be replaced in some areas like transportation, and the difficulty of developing countries to find substitutes for this energy source, could also lead developed countries to keep the energy resources for a better utilization, and give the countries which have no access to other resources, a possibility to develop.Thus, France has extensively enhanced nuclear energy for its electricity production, and, consequently, makes the necessary efforts for the knowledge of the whole fuel cycle.     

Order–disorder phase transition induced by swift ions in MgAl2O4 and ZnAl2O4 spinels

Grazing X-ray diffraction was used to study in details the behaviour of two spinels, ZnAl₂O₄ and MgAl₂O₄ irradiated by swift ions. Such an irradiation allows to have an important irradiated depth and then accurate diffraction diagrams. Rietveld refinement done on these diagrams clearly show an order–disorder transition due to a melting of cations under irradiation in these two spinels. More especially, these results clearly exhibit that no new phase is created under irradiation in MgAl₂O₄. Raman spectroscopy, sensitive to the crystallographic space group, seems to confirm this analysis.