Study on Micro Recoil Mechanism of the Weapon with a Nozzle and Two Chambers Separated by a Partition

In order to improve the recoil reduction ability of the weapon without reducing the projectile velocity, the weapon with a nozzle and two chambers separated by a partition is proposed. Taking the 35 mm caliber grenade launcher as the research object, the physical model of its launching process is proposed, and the one-dimensional two-phase flow interior ballistic model is established. MacCormack difference scheme is used to calculate the coupling of multiple physical fields formed by front and rear chambers and nozzles. Compared with the calculation results obtained by using the classical interior ballistic model, the correctness of the two-phase flow interior ballistic model is verified. The effects of the charge amount in the rear chamber and the size of the air guide hole in the barrel on the internal ballistic performance of the weapon with a nozzle and two chambers separated by a partition. The calculation results show that compared with conventional weapons, the recoil impulse can be reduced with maintaining muzzle velocity, and the recoil reduction efficiency can reach 72.27%, which is of great significance for improving weapon performance.

DC Self-Field Critical Current in Superconductor/Dirac-Cone Material/Superconductor Junctions and The Request for Ballistic Model Reexamination

Recently, several research groups have reported on anomalous enhancement of the self-field critical currents, Ic(sf,T), at low temperatures in superconductor/Dirac-cone material/superconductor (S/DCM/S) junctions. Some papers attributed the enhancement to the low-energy Andreev bound states arising from winding of the electronic wave function around DCM. In this paper, Ic(sf,T) in S/DCM/S junctions have been analyzed by two approaches: modified Ambegaokar-Baratoff and ballistic Titov-Beenakker models. It is shown that the ballistic model is an inadequate tool to analyze experimental data from S/DCM/S junctions. The primary mechanism for limiting superconducting current in S/DCM/S junctions is different from the conventional view that the latter is the maximum value within the order parameter phase variation. Thus, there is a need to develop a new model for self-field critical currents in S/DCM/S systems.