Anomalous and Instable Ultrasonic Evidence for a Structural Phase Transition at the Critical Value Vc in Electrorheological Suspensions
Issue:
Volume 8, Issue 3, May 2019
Pages:
37-39
Received:
15 June 2019
Accepted:
26 July 2019
Published:
23 August 2019
Abstract: Using the sample cell designed by ourselves and the electrorheological (ER) samples, one of them is imported from USA (sample 1), the other one is made from tsinghua university (sample2), we perform a series experiments with these two ER samples, and observe some curious phenomena; such as the ultrasonic study on the longitudinal sound velocity in electrorheological (ER) suspensions reveals the existence of a serious shear instability at the critical value of applied voltages, the evidence retains the time of about a few milliseconds; moreover, the experiments on ER samples demonstrate that there is a saturation value for the ultrasonic attenuation when the applied voltages arrive a critical value Vc, which resemble to the cases of a lot of superconductors at the critical value of temperature Tc; In the experiments on the I-V characteristic of the two ER samples, we observe that an abrupt change in the I-V characteristics occurs at the critical value Vc of the applied voltages, furthermore, the I-V characteristic of either of the two ER samples is linear after the applied voltages overpass the critical value Vc, just as same as the I-V characteristic of metal conductors. Therefore, it is reasonable to suggest that this anomalous ultrasonic evidence we observed in the experiments corresponds to a structural phase transition from liquidlike phase to metal-solidlike phase in the electrorheological suspensions.
Abstract: Using the sample cell designed by ourselves and the electrorheological (ER) samples, one of them is imported from USA (sample 1), the other one is made from tsinghua university (sample2), we perform a series experiments with these two ER samples, and observe some curious phenomena; such as the ultrasonic study on the longitudinal sound velocity in ...
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Implementation of the 8-Nucleon Yakubovsky Formalism for Halo Nucleus 8He
Eskandar Ahmadi Pouya,
Ali Akbar Rajabi
Issue:
Volume 8, Issue 3, May 2019
Pages:
40-49
Received:
28 May 2019
Accepted:
6 August 2019
Published:
10 September 2019
Abstract: In order to study the bound-state structure of the Helium halo nuclei, the 8-nucleon Yakubovsky formalism has been implemented for 8He in a 5-body sub-cluster model, i.e. α+n+n+n+n. In this case, the 8-nucleon Yakubovsky equations have been obtained in the form of two coupled equations, based on the two independent components. In addition, by removing the contribution interactions of the 8 and 7’s bound nucleons in the formalism, the obtained equations explicitly reduce to the 6-nucleon Yakubovsky equations for 6He, in the case of effective 3-body model, i.e. α+n+n. In view of the expectation for the dominant structure of 8He, namely an inert α-core and four loosely-bound neutrons, Jacobi configurations of the two components in momentum space have been represented to provide technicalities which were considered useful for a numerical performance, such as bound-state calculations and momentum density distributions for halo-bound neutrons.
Abstract: In order to study the bound-state structure of the Helium halo nuclei, the 8-nucleon Yakubovsky formalism has been implemented for 8He in a 5-body sub-cluster model, i.e. α+n+n+n+n. In this case, the 8-nucleon Yakubovsky equations have been obtained in the form of two coupled equations, based on the two independent components. In addition, by remov...
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