The prediction of the fragment velocity distribution of a cylindrical cased charge with end caps is one of the key issues to assess the damage efficiency of the warhead. However, limited work has been conducted to pre...The prediction of the fragment velocity distribution of a cylindrical cased charge with end caps is one of the key issues to assess the damage efficiency of the warhead. However, limited work has been conducted to predict the fragment velocity distributions along the axis of cylindrical cased charges with end caps. This paper presents a study of the velocity distribution of fragments caused by the explosion of a cylindrical cased charge with end caps. The fragment velocity distribution and the end cap velocity were determined by an X-ray radiography method, and the axial fragment distribution was determined by witness plates. It was found that the velocities of fragments, especially near the edge, were increased when the end caps were added, and the position of maximum velocity is closer to the non-detonation end. The fragment velocities were increased, and the fragment projection range was decreased with the increase of the thickness of the end cap. A formula for fragment velocity distributions of a cylindrical cased charge with end caps, which is based on Huang’s formula, was proposed by the theoretical analysis and data fitting and validated experimentally. The results indicate that the proposed formula is accurate in predicting the fragment velocity distribution along the axis of a cylindrical cased charge with end caps detonated at one end.展开更多
Although the dynamic instability of microtubules(MTs)is fundamental to many cellular functions,quiescent MTs with unattached free distal ends are commonly present and play important roles in various events to power ce...Although the dynamic instability of microtubules(MTs)is fundamental to many cellular functions,quiescent MTs with unattached free distal ends are commonly present and play important roles in various events to power cellular dynamics.However,how these free MT tips are stabilized remains poorly understood.Here,we report that centrosome and spindle pole protein 1(CSPP1)caps and stabilizes both plus and minus ends of static MTs.Real-time imaging of laser-ablated MTs in live cells showed deposition of CSPP1 at the newly generated MT ends,whose dynamic instability was concomitantly suppressed.Consistently,MT ends in CSPP1-overexpressing cells were hyper-stabilized,while those in CSPP1-depleted cells were much more dynamic.This CSPP1-elicited stabilization of MTs was demonstrated to be achieved by suppressing intrinsic MT catastrophe and restricting polymerization.Importantly,CSPP1-bound MTs were resistant to mitotic centromere-associated kinesin-mediated depolymerization.These findings delineate a previously uncharacterized CSPP1 activity that integrates MT end capping to orchestrate quiescent MTs.展开更多
基金financial support from the exploratory project of State Key Laboratory of Explosion Science and Technology, China (No. QNKT19-09)。
文摘The prediction of the fragment velocity distribution of a cylindrical cased charge with end caps is one of the key issues to assess the damage efficiency of the warhead. However, limited work has been conducted to predict the fragment velocity distributions along the axis of cylindrical cased charges with end caps. This paper presents a study of the velocity distribution of fragments caused by the explosion of a cylindrical cased charge with end caps. The fragment velocity distribution and the end cap velocity were determined by an X-ray radiography method, and the axial fragment distribution was determined by witness plates. It was found that the velocities of fragments, especially near the edge, were increased when the end caps were added, and the position of maximum velocity is closer to the non-detonation end. The fragment velocities were increased, and the fragment projection range was decreased with the increase of the thickness of the end cap. A formula for fragment velocity distributions of a cylindrical cased charge with end caps, which is based on Huang’s formula, was proposed by the theoretical analysis and data fitting and validated experimentally. The results indicate that the proposed formula is accurate in predicting the fragment velocity distribution along the axis of a cylindrical cased charge with end caps detonated at one end.
基金supported by grants from the Ministry of Science and Technology of China and the National Natural Science Foundation of China(2022YFA1303100,32090040,92254302,2022YFA0806800,91854203,31621002,2017YFA0503600,21922706,and 92153302 to Xing Liu,2022YFA1302700 to Z.W.,32100612 to Xu Liu)the Ministry of Education of China(IRT_17R102,20113402130010,and YD2070006001 to Xing Liu)+3 种基金the Plans for Major Provincial Science&Technology Projects of Anhui Province(202303a0702003 to Xing Liu)the Fundamental Research Funds for the Central Universities(KB9100000007 and KB9100000013 to Xing Liu)University of Science and Technology of China Start-up Fund(KY9990000167 to Z.W.)Zhejiang Provincial Natural Science Foundation(LY23C070002 to W.W.)。
文摘Although the dynamic instability of microtubules(MTs)is fundamental to many cellular functions,quiescent MTs with unattached free distal ends are commonly present and play important roles in various events to power cellular dynamics.However,how these free MT tips are stabilized remains poorly understood.Here,we report that centrosome and spindle pole protein 1(CSPP1)caps and stabilizes both plus and minus ends of static MTs.Real-time imaging of laser-ablated MTs in live cells showed deposition of CSPP1 at the newly generated MT ends,whose dynamic instability was concomitantly suppressed.Consistently,MT ends in CSPP1-overexpressing cells were hyper-stabilized,while those in CSPP1-depleted cells were much more dynamic.This CSPP1-elicited stabilization of MTs was demonstrated to be achieved by suppressing intrinsic MT catastrophe and restricting polymerization.Importantly,CSPP1-bound MTs were resistant to mitotic centromere-associated kinesin-mediated depolymerization.These findings delineate a previously uncharacterized CSPP1 activity that integrates MT end capping to orchestrate quiescent MTs.
