Search results for "reflection"
showing 10 items of 645 documents
Four-Color Infrared Bolometer System for One-Meter Telescope
1978
As a part of the collaborative program between the University of Palermo and the Center for Astrophysics (HCO/SAO) a far infrared photometer has been designed, fabricated and tested by the Univsity of Palermo to be used as a focal plane instrument on the Center of Astrophysics/University of Arizona balloon-borne 102 cm telescope (Fazio et a1. 1974).
Generation of radiative knots in a randomly pulsed protostellar jet
2009
HH objects are characterized by a complex knotty morphology detected mainly along the axis of protostellar jets in a wide range of bands. Evidence of interactions between knots formed in different epochs have been found, suggesting that jets may result from the ejection of plasma blobs from the source. We aim at investigating the physical mechanism leading to the irregular knotty structure observed in jets in different bands and the complex interactions occurring among blobs of plasma ejected from the stellar source. We perform 2D axisymmetric HD simulations of a randomly ejected pulsed jet. The jet consists of a train of blobs which ram with supersonic speed into the ambient medium. The in…
The effective diffusion coefficient in a one-dimensional discrete lattice with the inclusions
2015
Abstract The expression for the effective diffusion coefficient in one-dimensional discrete lattice model of random walks in matrix with inclusions and unequal hopping lengths is derived. This allowed us to suggest a physical interpretation to the concentration jump – ad hoc parameter commonly used in extended effective medium theory for accounting particle partial reflection on the boundary matrix–inclusion. The analytical results obtained are in excellent agreement with computer simulations.
A re-analysis of the NuSTAR and XMM-Newton broad-band spectrum of Serpens X-1
2017
Context. High-resolution X-ray spectra of neutron star low-mass X-ray binaries (LMXBs) in the energy range 6.4-6.97 keV are often characterized by the presence of K alpha transition features of iron at different ionization stages. Since these lines are thought to originate by reflection of the primary Comptonization spectrum over the accretion disk, the study of these features allows us to investigate the structure of the accretion flow close to the central source. Thus, the study of these features gives us important physical information on the system parameters and geometry. Ser X-1 is a well studied LMXB that clearly shows a broad iron line. Several attempts to fit this feature as a smear…
An antidamping spin–orbit torque originating from the Berry curvature
2014
Magnetization switching at the interface between ferromagnetic and paramagnetic metals, controlled by current-induced torques, could be exploited in magnetic memory technologies. Compelling questions arise regarding the role played in the switching by the spin Hall effect in the paramagnet and by the spin-orbit torque originating from the broken inversion symmetry at the interface. Of particular importance are the antidamping components of these current-induced torques acting against the equilibrium-restoring Gilbert damping of the magnetization dynamics. Here, we report the observation of an antidamping spin-orbit torque that stems from the Berry curvature, in analogy to the origin of the …
Simulation of propagation characteristics of ultrasonic guided waves in fractured long bone
2008
Using ultrasonic guided waves (GW) to assess fractures in long bones has gained considerable attention. This paper focuses on using an improved hybrid boundary element method (HBEM) to analyze and calculate reflection coefficients (RC) and transmission coefficients (TC) of low-order GWs for cracks with different depth-to-width ratios (d/w) in fractured long bones. The results showed that the primary received modes, which include the transmitted and reflected modes, are the same as the incident modes. For some values of d/w, the TC of different GW always had local maxima at adjacent frequencies. For some other cracks with different d/w, most of the TC curves had local maxima of which frequen…
SMIM in reflection imaging mode
2019
We present reflective SMIM (initials incoming from Spatially-Multiplexed Interferometric Microscopy) as an extremely simple and low cost way to convert a standard white-light microscope into a holographic one working under reflection imaging mode.
A common optical algorithm for the evaluation of specular spin polarized neutron and Mössbauer reflectivities
2001
Using the general approach of Lax for multiple scattering of waves a 2x2 covariant expression for the reflectivity of polarized slow neutrons of a magnetic layer structure of arbitrary complexity is given including polarization effects of the external magnetic field. The present formalism is identical to the earlier published one for the (nuclear) resonant X-ray (Mossbauer) reflectivity and properly takes the effect of the external magnetic field of arbitrary direction on the neutron beam into account. The form of the reflectivity matrix allows for an efficient numerical calculation.
Model-independent confirmation of theZ(4430)−state
2015
The decay $B^0\to \psi(2S) K^+\pi^-$ is analyzed using $\rm 3~fb^{-1}$ of $pp$ collision data collected with the LHCb detector. A model-independent description of the $\psi(2S) \pi$ mass spectrum is obtained, using as input the $K\pi$ mass spectrum and angular distribution derived directly from data, without requiring a theoretical description of resonance shapes or their interference. The hypothesis that the $\psi(2S)\pi$ mass spectrum can be described in terms of $K\pi$ reflections alone is rejected with more than 8$\sigma$ significance. This provides confirmation, in a model-independent way, of the need for an additional resonant component in the mass region of the $Z(4430)^-$ exotic sta…
Search for theZ(4430)−atBABAR
2009
We report the results of a search for Z(4430)^- decay to J/Ψ π^- or Ψ(2S)π^- in B(^-.0)→ J/Ψ π^-K^(0.+) and B^(-.0) → Ψ(2S)π^-K^(0.+) decays. The data were collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e^+e^- collider operating at center-of-mass energy 10.58 GeV, and the sample corresponds to an integrated luminosity of 413 fb^(-1). Each K π^- mass distribution exhibits clear K^*(892) and K_2^*(1430) signals, and the efficiency-corrected spectrum is well described by a superposition of the associated Breit-Wigner intensity distributions, together with an S-wave contribution obtained from the LASS I=1/2 K π^- scattering amplitude measurements. Each K π^- angular dist…