Researches aforementioned provide effective numerical theore

Researches aforementioned provide effective numerical/theoretical descriptions of expansion behavior of PELE when small-caliber projectiles penetrating thin target at high impact velocity. Here we presented a similar study on large-caliber PELE projectile (130 mm) with various thickness steel jacket against 30 mm RHA plates at low impact velocity (415 m s−1). By considering an additional radial shock wave originating from transmission at jacket/filling interface, an analytical model developed by Verreault was presented to accurately describe pressure evolution, lateral expansion and jacket fragmentation in this sanguinarine condition. To predict damage area on behind-armor witness target that was far away (2 m) from target plate, empirical investigation were conducted, focusing on relation between maximum emission angle of PELE behind-armor fragments and maximum axial/radial velocity. Further comparisons between analytical and experimental/numerical data verified above models and then revealed influence of d/D on lateral expansion and jacket fragmentation of large-caliber PELE.
Experiments
Numerical simulations
Discussion
Conclusions By large-caliber PELE with various d/D against RHA plate at low velocity of 415 m s−1, impact experiments against 30 mm RHA target were carried out. Numerical simulations were also conducted to monitor progress of PELE expansion and fragmentation in this condition. According to experimental and numerical results, an analytical model that taking an additional radial shock wave into consideration was presented to describe lateral effect, as well as an empirical approach for damage area on witness target. Further comparisons and discussion drew conclusions including:
Introduction RNA helicases are molecular motors that bind or remodel RNA and ribonucleoprotein (RNP) complexes in an ATP-dependent manner [[1], [2], [3]]. RNA helicases can be found in all the helicase superfamilies except for SF6 [4,5], exist in almost all living organisms, and play important roles in dsRNA unwinding, pre-mRNA editing, splicing, translation initiation, and other fundamental processes [[5], [6], [7]]. The majority of RNA helicases belonging to SF2 are comprised of five families, three of which are termed the DEAD-box, DEAH/RHA and viral DExH protein families [8]. The DEAH/RHA family is the second largest RNA helicase with eight sequence motifs (I, Ia, Ib, II, III, IV, V and VI) that are conserved from bacteria to humans [[8], [9], [10], [11], [12]]. Motifs I, II and VI are related to ATP binding and hydrolysis, whereas, motifs Ia, Ib, IV and V may be involved in RNA binding [13]. DEAH refers to the sequence of the helicase motif II, the equivalent of the DEAD-box, which reads D-E-A-H, for about half of the family members. RHA stands for RNA helicase A, the best-characterized protein of the remaining family members, all of which bear close resemblance to this enzyme on the sequence level. The DEAH/RHA family shares a conserved catalytic center formed by two RecA-like domains connected by a short flexible linker [1,14,15].