Search results for " Axis"
showing 10 items of 188 documents
Polyadic devil's lenses.
2009
Devil’s lenses (DLs) were recently proposed as a new kind of kinoform lens in which the phase structure is characterized by the “devil’s staircase” function. DLs are considered fractal lenses because they are constructed following the geometry of the triadic Cantor set and because they provide self-similar foci along the optical axis. Here, DLs are generalized allowing the inclusion of polyadic Cantor distributions in their design. The lacunarity of the selected polyadic fractal distribution is an additional design parameter. The results are coined polyadic DLs. Construction requirements and interrelations among the different parameters of these new fractal lenses are also presented. It is …
Cricket combined mechanoreceptors and kicking response
1977
1. Only those filiform hairs on the cerci ofGryllus, which are coupled with campaniform sensilla, show a) a thickening of the hair shaft at the height of the upper ring lamella of their sockets and b) a thin cuticular membrane, which surrounds their sockets. While thefiliform hairs themselves are deflected either parallel to the long axis of the cerci or perpendicular to it, thesockets of the filiform hairs may be deflected preferentially in the proximal and distal direction. 2. Spike potentials can be recorded from the sensory cells of the filiform hairs as long as these are deflected in a weak air current, but not during permanent deflection in strong air streams when they touch the inner…
Extinction law classification and lens redshift estimate by means of the principal component analysis
2007
Aims. We propose a method based on the Principal Component Analysis (PCA) to classify and estimate the redshift of an extinction law in a distant gravitational lens galaxy. Such extinction laws are very poorly known and an efficient method to characterize them is badly needed. Methods. We first compute the principal axes of an exhaustive collection of redshifted theoretical extinction laws. Then, we project on these new axes the extinction law we wish to classify. The position of its projection among those redshifted extinction laws from the collection allows us to characterize it and to estimate its redshift. Results. Monte Carlo simulations show that the method is efficient and relatively…
Shears mechanism in109Cd
2000
Lifetimes of high-spin states in two $\ensuremath{\Delta}I=1$ bands and one $\ensuremath{\Delta}I=2$ band in ${}^{109}\mathrm{Cd}$ have been measured using the Doppler shift attenuation method in an experiment performed using the ${}^{96}\mathrm{Zr}{(}^{18}\mathrm{O},5n)$ reaction with the GAMMASPHERE array. Experimental total angular momenta and reduced transition strengths for both $\ensuremath{\Delta}I=1$ bands were compared with tilted axis cranking (shears mechanism) predictions and the $\ensuremath{\Delta}I=2$ band with principal axis cranking predictions, based on configurations involving two proton ${g}_{9/2}$ holes and one or three valence quasineutrons from the ${h}_{11/2}$ and mi…
Triaxial shape with rotation around the longest principal axis inGd142
2008
The cranking model is used to describe rotational bands. We investigate the approach of using diabatic configurations and minimizing the particle-number projected energy in a mesh of both lambda, Delta and deformation parameters. We use the method to interpret recent experimental data in Gd-142 and conclude that for the highest spin states observed (I approximate to 30), the nucleus is triaxial and builds spin by rotating around the classically unfavored longest axis.
Experimental evidence for chirality in the odd-A 105Rh
2004
Abstract High-spin states in 105 Rh were populated by the 96 Zr( 13 C, p3n) reaction at beam energies of 51 and 58 MeV, and studied using the EUROBALL IV γ -ray spectrometer and the DIAMANT charged particle array. A pair of nearly degenerate Δ I = 1 three-quasiparticle bands with the same spins and parity have been observed. Comparison of the experimental results with tilted axis cranking calculations confirms the chiral character of the two bands, while arguments based on the excitation of particles within the π g 9 / 2 ν ( h 11 / 2 ) 2 configuration of the yrast band and comparison with the previously observed γ band exclude the other possible interpretations. This is the first experiment…
The distribution of the rotational transition strength in warm nuclei studied through γ-ray correlations
1995
Abstract The study of damping of rotational motion applying te rotational plane mapping (RPM) method is presented and discussed. The aim of this technique is to extract the distribution of the rotational transition strength from an analysis of the shape of the “central valley” of two- and three-dimensional γ-ray spectra. The method is applied to a triple γ-coincidence data set of 162,163Tm nuclei formed in 37Cl+130Te reactions. The rotational transition strength is obtained as a function of rotational frequency for selected regions of entry states, and the width is found to be rather constant and approximately equal to 80 keV. This value is significantly smaller than the value predicted the…
Continuously Variable Periodic Test Target
1987
CONTINUOUSLY VARIABLE PERIODIC TEST TARGETP. ANDRES*, J. OJEDA- CASTANEDAt, and J.C. BARREIRO*tINAOE, Apartado Postal 216, 72000 Puebla, Pue., Mexico*Departamento de Optica, Universidad de Valencia, 46100 Burjasot, Spain1. INTRODUCTIONThe modulus of the optical transfer function (MTF) of the eye or any other optical system is usuallyevaluated by imaging either several gratings each with different spatial frequency, or a single test tar-get having patterns with different frequencies (USAF resolution chart). In any of these two usual proce-dures, the measurement of the MTF is made at discrete values of the spatial frequency.Here we describe a method based on the self -imaging phenomenon for p…
Impact of anisotropy on the noncritical squeezing properties of two-transverse-mode optical parametric oscillators
2013
In a series of articles we studied the quantum properties of a degenerate optical parametric oscillator tuned to the first family of transverse modes at the subharmonic. We found that, for a cavity having rotational symmetry respect to the optical axis, a TEM$_{10}$ mode with an arbitrary orientation in the transverse plane is emitted above threshold. We proved then that quantum noise induces a random rotation of this bright TEM$_{10}$ mode in the transverse plane, while the mode orthogonal to it, the so-called dark mode, has perfect quadrature squeezing irrespective of the distance to threshold (noncritical squeezing). This result was linked to the spontaneous rotational symmetry breaking …
BeppoSAX serendipitous discovery of the X-ray pulsar SAX J1802.7-2017
2003
We report on the serendipitous discovery of a new X-ray source, SAX J1802.7-2017, ~22' away from the bright X-ray source GX 9+1, during a BeppoSAX observation of the latter source on 2001 September 16-20. SAX J1802.7-2017 remained undetected in the first 50 ks of observation; the source count rate in the following ~300 ks ranged between 0.04 c/s and 0.28 c/s, corresponding to an averaged 0.1-10 keV flux of 3.6 10^{-11} ergs cm^{-2} s^{-1}. We performed a timing analysis and found that SAX J1802.7-2017 has a pulse period of 139.612 s, a projected semimajor axis of a_x sin i ~ 70 lt-s, an orbital period of ~4.6 days, and a mass function f(M) ~ 17 Msun. The new source is thus an accreting X-ra…