An efficient cooling effect is put forward, by means of external electric or magnetic fields along hysteresis loops. A simplified model of hysteresis is used for numerical illustration. The model is based upon a second-order expansion of the energy in powers of polarization and external field. The electrocaloric effect along hysteresis loops is discussed for comparison.
The differential cross sections for alpha-particle emission at an angle of 0 $${}^{\circ}$$ in the reactions induced by a 6-MeV/nucleon $${}^{56}$$ Fe beams incident to $${}^{238}$$ U and $${}^{181}$$ Ta targets were measured versus the alpha-particle energy by means of a high-resolution magnetic analyzer (MAVR setup). The resulting spectra were found to contain fast alpha particles of energy corresponding to the two- and three-body exit reaction channels, including alpha particles of energy close to the two-body kinematical limit. The data obtained in this experiment were analyzed on the basis of the moving-source model. The emission of nonequilibrium alpha particles in the forward direction from the heavier target nucleus upon the complete or incomplete fusion of nuclei was revealed within the time-dependent quantum approach.
The Siegert states are approached in framework of Bloch-Lane-Robson formalism for quantum collisions. The Siegert state is not described by a pole of Wigner R-matrix but rather by the equation 1 − RnnLn = 0, relating R-matrix element Rnn to decay channel logarithmic derivative Ln. Extension of Siegert state equation to multichannel system results in the replacement of channel R- matrix element Rnn by its reduced counterpart Rnn. One proves the Siegert state is a pole, (1 − RnnLn)−1, of multichannel collision matrix. The Siegert equation 1 − RnnLn = 0, (n – Rydberg channel), implies basic results of Quantum Defect Theory as Seaton’s theorem, complex quantum defect, channel resonances and threshold continuity of averaged multichannel collision matrix elements.
One of the important techniques used at JET for studying fast ions is based on measurements of gamma rays which are produced as a result of nuclear reactions between ions and plasma impurities. The intense neutron and gamma-ray fluxes expected during a DT campaign impose dew requirements on detector characteristics used in such experiments. In addition to good energy resolution, detectors must also be characterized by a high signal-to-noise ratio and allow to perform measurements at high counting rate about 1 Mcps. The scintillators which fulfill these requirements are, among others, LaBr3:Ce, already tested at JET, and CeBr3 with a scintillation decay time of similar to 20 ns. We report on measurements which were performed with a detector module equipped with a 3" x 3" CeBr3 scintillator and with an active voltage divider AVD@NCBJ, designed and constructed at NCBJ. Standard gamma -ray sources, as well as a PuBe source, were used for measurements. The comparison of measured and Monte Carlo simulated spectra is also presented. (C) 2017 Elsevier B.V. All rights reserved.
Unphysical terms in the elastic Hertz potentials are identified, and a regularization procedure is devised for removing them. The solutions of the equation of elastic motion are given for tensorial forces (seismic moment forces) and vectorial forces (Stokes problem) concentrated in both space and time.
