As an army main battle equipment, it is required that the tank should have high firing accuracy and high first round hit probability during marching. The initial disturbance of the projectile is the premier factor tha...As an army main battle equipment, it is required that the tank should have high firing accuracy and high first round hit probability during marching. The initial disturbance of the projectile is the premier factor that takes effect on the marching fire accuracy of the tank. And the marching fire accuracy of the tank depends on the launch dynamics behaviors of the tank. In this paper, the launch dynamics theory of a tank marching fire is studied, and its launch dynamics model is established. Based on the transfer matrix method for multibody system(MSTMM) and the automatic deduction theorem of overall transfer equations, the overall transfer equation and the overall transfer matrix of a tank multibody system are deduced; the launch dynamics equations of the tank marching fire are deduced, and the dynamic response of the tank system, the motion of projectile in barrel, the initial disturbance of the projectile and the vertical target dispersion are exactly simulated; meanwhile, the results of simulation are verified by tests. This work provides both theoretical foundation and simulation approaches for improving the marching fire accuracy of the tank.展开更多
3D traveltime calculation is widely used in seismic exploration technologies such as seismic migration and tomography. The fast marching method （FMM） is useful for calculating 3D traveltime and has proven to be effi...3D traveltime calculation is widely used in seismic exploration technologies such as seismic migration and tomography. The fast marching method （FMM） is useful for calculating 3D traveltime and has proven to be efficient and stable. However, it has low calculation accuracy near the source, which thus gives it low overall accuracy. This paper proposes a joint traveltime calculation method to solve this problem. The method firstly employs the wavefront construction method （WFC）, which has a higher calculation accuracy than FMM in calculating traveltime in the small area near the source, and secondly adopts FMM to calculate traveltime for the remaining grid nodes. Due to the increase in calculation precision of grid nodes near the source, this new algorithm is shown to have good calculation precision while maintaining the high calculation efficiency of FMM, which is employed in most of the computational area. Results are verified using various numerical models.展开更多
Dentin,the main component of dental hard tissues,is produced by differentiated odontoblasts.How odontoblast differentiation is regulated remains understudied.Here,we screen that the expression of membrane-associated R...Dentin,the main component of dental hard tissues,is produced by differentiated odontoblasts.How odontoblast differentiation is regulated remains understudied.Here,we screen that the expression of membrane-associated RING finger protein 2(March2) is the highest among all March family members,with an increasing trend during odontoblast differentiation.In mouse incisors and molars,MARCH2 is moderately expressed in the undifferentiated dental papilla cells and strongly expressed in the odontoblasts.Knockdown and overexpression experiments demonstrate that MARCH2 inhibits odontoblastic differentiation of mouse dental papilla cells(mDPCs).Additionally,both March2 deficient mice and mice with odontoblast specific knockdown of March2 exhibit the phenotype of increased dentin thickness,accelerated dentin deposition as well as elevated expression levels of odontoblast markers compared with control littermates.Therefore,MARCH2 plays an inhibitory role in odontoblast differentiation.Mechanistically,MARCH2 interacts with protein tyrosine phosphatase receptor delta(PTPRD) and facilitates its K27-linked polyubiquitination and subsequent degradation,which is dependent on the ligase activity of MARCH2.The presence of MARCH2promotes the translocation of PTPRD from the cell membrane to the lysosome,thereby enhancing its degradation via the lysosomal pathway.Further experiments show that knockdown of endogenous Ptprd impairs odontoblastic differentiation of mDPCs.Ptprd and March2 double knockdown in mDPCs apparently reversed the enhanced odontoblastic differentiation by knockdown of March2 alone,indicating that MARCH2 inhibits odontoblastic differentiation by promoting PTPRD degradation.This study unveils a novel mechanism where an E3 ubiquitin ligase regulates odontoblast differentiation through post-translational modification of a membrane protein,highlighting a promising direction for future exploration.展开更多
At 11:00 p.m. on January 13, 2026, floodlights illuminated the launch pad at the Hainan Commercial Space Launch Site in Wenchang,south China’s Hainan Province. A Long March-8A (CZ-8A) carrier rocket lifted off with a...At 11:00 p.m. on January 13, 2026, floodlights illuminated the launch pad at the Hainan Commercial Space Launch Site in Wenchang,south China’s Hainan Province. A Long March-8A (CZ-8A) carrier rocket lifted off with a steady roar, its exhaust lighting up the night sky as it delivered a satellite into its designated orbit.The development of China’s first commercial space launch site has been striking. Since its inaugural launch in2024, it has completed 11 missions in less than 14 months—each a success.展开更多
基金the National Natural Science Foundation of China(No.61304137)the Equipment Preresearch Mutual Application Techniques Foundation of China(No.9140A10041013BQ02143)
文摘As an army main battle equipment, it is required that the tank should have high firing accuracy and high first round hit probability during marching. The initial disturbance of the projectile is the premier factor that takes effect on the marching fire accuracy of the tank. And the marching fire accuracy of the tank depends on the launch dynamics behaviors of the tank. In this paper, the launch dynamics theory of a tank marching fire is studied, and its launch dynamics model is established. Based on the transfer matrix method for multibody system(MSTMM) and the automatic deduction theorem of overall transfer equations, the overall transfer equation and the overall transfer matrix of a tank multibody system are deduced; the launch dynamics equations of the tank marching fire are deduced, and the dynamic response of the tank system, the motion of projectile in barrel, the initial disturbance of the projectile and the vertical target dispersion are exactly simulated; meanwhile, the results of simulation are verified by tests. This work provides both theoretical foundation and simulation approaches for improving the marching fire accuracy of the tank.
基金supported by NSFC(Nos.41274120,41404085,and 41504084)
文摘3D traveltime calculation is widely used in seismic exploration technologies such as seismic migration and tomography. The fast marching method （FMM） is useful for calculating 3D traveltime and has proven to be efficient and stable. However, it has low calculation accuracy near the source, which thus gives it low overall accuracy. This paper proposes a joint traveltime calculation method to solve this problem. The method firstly employs the wavefront construction method （WFC）, which has a higher calculation accuracy than FMM in calculating traveltime in the small area near the source, and secondly adopts FMM to calculate traveltime for the remaining grid nodes. Due to the increase in calculation precision of grid nodes near the source, this new algorithm is shown to have good calculation precision while maintaining the high calculation efficiency of FMM, which is employed in most of the computational area. Results are verified using various numerical models.
基金supported by grants from the National Natural Science Foundation of China (82370913,82170914 to Guohua Yuan and 82270947 to Guobin Yang)the National Natural Science Foundation of China Key Program (82230029 to Z.C)+1 种基金the Fundamental Research Funds for the Central Universities (2042022dx0003)the Innovation Project of Municipal Science and Technology Bureau (2023020201010170) to Guohua Yuan。
文摘Dentin,the main component of dental hard tissues,is produced by differentiated odontoblasts.How odontoblast differentiation is regulated remains understudied.Here,we screen that the expression of membrane-associated RING finger protein 2(March2) is the highest among all March family members,with an increasing trend during odontoblast differentiation.In mouse incisors and molars,MARCH2 is moderately expressed in the undifferentiated dental papilla cells and strongly expressed in the odontoblasts.Knockdown and overexpression experiments demonstrate that MARCH2 inhibits odontoblastic differentiation of mouse dental papilla cells(mDPCs).Additionally,both March2 deficient mice and mice with odontoblast specific knockdown of March2 exhibit the phenotype of increased dentin thickness,accelerated dentin deposition as well as elevated expression levels of odontoblast markers compared with control littermates.Therefore,MARCH2 plays an inhibitory role in odontoblast differentiation.Mechanistically,MARCH2 interacts with protein tyrosine phosphatase receptor delta(PTPRD) and facilitates its K27-linked polyubiquitination and subsequent degradation,which is dependent on the ligase activity of MARCH2.The presence of MARCH2promotes the translocation of PTPRD from the cell membrane to the lysosome,thereby enhancing its degradation via the lysosomal pathway.Further experiments show that knockdown of endogenous Ptprd impairs odontoblastic differentiation of mDPCs.Ptprd and March2 double knockdown in mDPCs apparently reversed the enhanced odontoblastic differentiation by knockdown of March2 alone,indicating that MARCH2 inhibits odontoblastic differentiation by promoting PTPRD degradation.This study unveils a novel mechanism where an E3 ubiquitin ligase regulates odontoblast differentiation through post-translational modification of a membrane protein,highlighting a promising direction for future exploration.
文摘At 11:00 p.m. on January 13, 2026, floodlights illuminated the launch pad at the Hainan Commercial Space Launch Site in Wenchang,south China’s Hainan Province. A Long March-8A (CZ-8A) carrier rocket lifted off with a steady roar, its exhaust lighting up the night sky as it delivered a satellite into its designated orbit.The development of China’s first commercial space launch site has been striking. Since its inaugural launch in2024, it has completed 11 missions in less than 14 months—each a success.
