Search results for "signal processing"
showing 10 items of 2451 documents
Instantaneous root mean squire value of the acoustic emission as a means of measuring partial discharges
2003
The author presents the measurement results of the parameter A/sub RMS/ for three types of partial discharges (PDs) generated in a typical high-voltage system: on pressboard, on resin, and on glass. A typical run of A/sub RMS/ on an X-Y register is shown. It manifests a relatively stable instantaneous root mean square value of the electric signal converted from the acoustic signal as a function of time. Results obtained for the three surfaces demonstrate that the parameter A/sub RMS/ is perfectly suitable for characterizing PDs measured by the acoustic method. It is univocally connected with the energy of the generated PD. >
Exchange-correlation energy of a multicomponent two-dimensional electron gas
2003
We discuss the exchange-correlation energy of a multicomponent (multi-valley) two-dimensional electron gas and show that an extension of the recent parametrisation of the exchange-correlation energy by Attacalite et al (Phys. Rev. Lett. 88, 256601 (2002)) describes well also the multicomponent system. We suggest a simple mass dependence of the correlation energy and apply it to study the phase diagram of the multicomponent 2D electron (or hole) gas. The results show that even a small mass difference of the components (e.g. heavy and light holes) decreases the concentration of the lighter components already at relatively high densities.
Study of thepd→pdηreaction
2007
A study of the pd{yields}pd{eta} reaction in the energy range where the recent data from Uppsala are available is done in the two-step model of {eta} production including the final state interaction. The {eta}-d final state interaction is incorporated through the solution of the Lippmann Schwinger equation using an elastic scattering matrix element, T{sub {eta}}{sub d{yields}}{sub {eta}}{sub d}, which is required to be half off-shell. It is written in a factorized form, with an off-shell form factor multiplying an on-shell part given by an effective range expansion up to the fourth power in momentum. The parameters of this expansion have been taken from an existing recent relativistic Fadde…
Description of thef2(1270),ρ3(1690),f4(2050),ρ5(2350), andf6(2510)resonances as multi-ρ(770)states
2010
In a previous work regarding the interaction of two $\ensuremath{\rho}(770)$ resonances, the ${f}_{2}(1270)$ (${J}^{PC}={2}^{++}$) resonance was obtained dynamically as a two-$\ensuremath{\rho}$ molecule with a very strong binding energy, 135 MeV per $\ensuremath{\rho}$ particle. In the present work we use the $\ensuremath{\rho}\ensuremath{\rho}$ interaction in spin 2 and isospin 0 channel to show that the resonances ${\ensuremath{\rho}}_{3}(1690)$ (${3}^{--}$), ${f}_{4}(2050)$ (${4}^{++}$), ${\ensuremath{\rho}}_{5}(2350)$ (${5}^{--}$), and ${f}_{6}(2510)$ (${6}^{++}$) are basically molecules of increasing number of $\ensuremath{\rho}(770)$ particles. We use the fixed center approximation o…
An experiment on wind energy
2012
We discuss an experiment on wind energy performed with home-made apparatus. The experiment reproduces a laboratory windmill, which can pump water from a lower level to a higher one. By measuring the gain of the gravitational potential energy of the pumped water, one can determine the power extracted from the wind. The activity was carried out with high-school students, in the framework of the Italian National Plan for Scientific Degrees-Physics. The proposed experiment allows teachers to discuss renewable energy sources with students whose knowledge of physics is limited to mechanics. It gives students the possibility to gain experience with energy and to increase their awareness of this re…
Observation of D0→K1(1270)−e+νe
2021
Using 2.93 fb^{-1} of e^{+}e^{-} collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} semileptonic decay is presented. The statistical significance of the decay D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is greater than 10σ. The branching fraction of D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is measured to be (1.09±0.13_{-0.16}^{+0.09}±0.12)×10^{-3}. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K_{1}(1270)^{-}→K^{-}π^{+}π^{-}. The fraction of longitudinal polarization in D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is determined for the first time t…
Measurement of the absolute branching fraction of the inclusive semileptonic $\Lambda_c^+$ decay
2018
Physical review letters 121(25), 251801 (2018). doi:10.1103/PhysRevLett.121.251801
J-File Sum Rule Tests for the 3s-3p Transition Array in Singly Ionized Nitrogen - Comparison of Measured and Calculated Data
2005
1. IntroductionIn recent years quite a large number of transition probabilities of spectrallines of light elements have been determined including data for singly ionizednitrogen [1{7]. Some of these experimental as well as theoretical studies providealso data for a few triplet{singlet intersystem transitions, being very interestinge.g. from astrophysical point of view. The energy level system of NII has adistinguished feature compared to the neighboring two members of the carbonisoelectronic sequence (CI, OIII) | the energy difierence between the excitedterms 3
Diindenoanthracene Diradicaloids Enable Rational, Incremental Tuning of Their Singlet-Triplet Energy Gaps
2020
Summary A fundamental understanding of the inherent electronic and magnetic properties of open-shell diradicaloids is essential so that these properties can be modified to create molecules that meet the potential needs of industry. However, there have been very few attempts to date to systematically accomplish this in diradicaloid compounds. Here, we present the synthetic, spectroscopic, and computational investigation of a series of molecules based on the diindeno[1,2-b:1′,2′-g]anthracene framework. Calculations suggest that by altering the transfer integral term, tab, we are able to manipulate the diradical character and, thus, ΔEST within this series of molecules. Experimentally determin…
Transitions in Presence of Short Laser Pulses
1990
Accurate numerical calculations are carried out to investigate the validity of the two-state approximation in the case of resonant interactions between electromagnetic radiation and atoms . Short pulses are considered and the presence of the atomic spectrum is modelled by introducing a third, nonresonant, state . We show that the harmonics of the pulse profile may play a significant role in the dynamics of the process and may cause energy nonconserving transitions between the atomic states. © 1990 Taylor & Francis Ltd.