Search results for " and Control"
showing 10 items of 385 documents
Dynamics for a simple graph using the U(N) framework for loop quantum gravity
2012
The implementation of the dynamics in loop quantum gravity (LQG) is still an open problem. Here, we discuss a tentative dynamics for the simplest class of graphs in LQG: Two vertices linked with an arbitrary number of edges. We find an interesting global U(N) symmetry in this model that selects the homogeneous/isotropic sector. Then, we propose a quantum Hamiltonian operator for this reduced sector. Finally, we introduce the spinor representation for LQG in order to propose a classical effective dynamics for this model.
Elastische Streuung langsamer Elektronen an einem Bi-Atomstrahl
1968
The angular distribution of electrons elastically scattered by bismuth atoms has been investigated in the angular range from 30 to 155° and with electron energies between 5 and 1200 eV. Theoretical data, which are available for energies above 100 eV, are in good agreement with experiment.
Winkelverteilung von elastisch und mit 6,7 eV-Energieverlust an freien Hg-Atomen gestreuten Elektronen
1970
The angular dependence of electrons scattered elastically and inelastically at free mercury atoms have been measured for electron energies between 20 and 300 eV (angular range from 20 to 155°).
Winkelverteilungen elastisch an Edelgas-Atomstrahlen gestreuter Elektronen; Spinpolarisation eines an Argon gestreuten 40 eV-Elektronenstrahls
1967
The angular distribution of electrons scattered elastically by rare-gas atomic beams (He, Ne, Ar, Kr, Xe) has been investigated over the angular range from 20° to 155° and with electron energies between 5 eV and 1000 eV. The results are compared with theory. Only for energies above 300 eV the agreement is good. The angular dependence of polarization P(Θ) of electrons, elastically scattered by a beam of argon atoms, is measured in a double scattering experiment for an electron energy of 40 eV. Maximum degree of polarization measured isP=12.5% ± 2.5%.
Messungen zur Ansprechwahrscheinlichkeit und Impulshöhenverteilung eines Sekundärelektronenvervielfachers
1966
The pulse height distribution of a CuBe-secondary electron multiplier has been investigated under the action of single electrons. For an energy interval from 150 eV to 1000 eV the maximum pulse height increases with increasing electron energy (the energy corresponding to maximum yield being 365±10 eV). This shows the statistics of secondary electron emission as being dependant on primary electron energy.
Laser ion beam production at CERN-ISOLDE: New features – More possibilities
2016
Abstract This article summarizes the current specifications and the latest features of the CERN-ISOLDE resonance ionization laser ion source (RILIS). This includes a description of the optical layout and the newly designed reference system. The ionization schemes for the laser ionized beams at ISOLDE are tabulated, including six new elements. All RILIS schemes are also made publicly available in the RILIS elements on-line database. Finally, we announce a paradigm shift in RILIS operation – the combination of a machine protection and a monitoring and control system has enabled on-call operation of the laser ion source for selected beams in 2014 and has become the standard mode of operation i…
Remarks on quadratic Hamiltonians in spaceflight mechanics
2006
A particular family of Hamiltonian functions is considered. Such functions are quadratic in the moment variables and arise in spaceflight mechanics when the averaged system of energy minimizing trajectories of the Kepler equation is computed. An important issue of perturbation theory and averaging is to provide integrable approximations of nonlinear systems. It turns out that such integrability properties hold here.
Discrete-valued-pulse optimal control algorithms: Application to spin systems
2015
International audience; This article is aimed at extending the framework of optimal control techniques to the situation where the control field values are restricted to a finite set. We propose generalizations of the standard GRAPE algorithm suited to this constraint. We test the validity and the efficiency of this approach for the inversion of an inhomogeneous ensemble of spin systems with different offset frequencies. It is shown that a remarkable efficiency can be achieved even for a very limited number of discrete values. Some applications in nuclear magnetic resonance are discussed.
Optimal Control of the Lotka-Volterra Equations with Applications
2022
In this article, the Lotka-Volterra model is analyzed to reduce the infection of a complex microbiote. The problem is set as an optimal control problem, where controls are associated to antibiotic or probiotic agents, or transplantations and bactericides. Candidates as minimizers are selected using the Maximum Principle and the closed loop optimal solution is discussed. In particular a 2d-model is constructed with 4 parameters to compute the optimal synthesis using homotopies on the parameters.
Caracterización de la suplementación de folatos en el embarazo a partir de la combinación de sistemas de información sanitaria.
2012
ResumenObjetivosExplorar la utilidad de la combinación de los sistemas de información sanitaria de la Agencia Valenciana de Salud (AVS) para caracterizar la suplementación de folatos en la población de embarazadas de la Comunidad Valenciana.MétodosCohorte de todas las mujeres que parieron en hospitales de la AVS durante 2009, que fueron seguidas retrospectivamente en la historia clínica electrónica ABUCASIS y el sistema GAIA de gestión de la prescripción para identificar el consumo de folatos en los 3 meses previos y posteriores a la concepción.ResultadosDe los 38.069 partos realizados en 2009 en hospitales de la AVS, 37.040 (97,3%) pudieron incluirse en los análisis. Un 34,0% de las mujere…