Warhead fragments motion trajectories tracking and spatio-temporal distribution reconstruction method based on high-speed stereo photography

High speed photography technique is potentially the most effective way to measure the motion parameter of warhead fragment benefiting from its advantages of high accuracy,high resolution and high efficiency.However,it faces challenge in dense objects tracking and 3D trajectories reconstruction due to the characteristics of small size and dense distribution of fragment swarm.To address these challenges,this work presents a warhead fragments motion trajectories tracking and spatio-temporal distribution reconstruction method based on high-speed stereo photography.Firstly,background difference algorithm is utilized to extract the center and area of each fragment in the image sequence.Subsequently,a multi-object tracking(MOT)algorithm using Kalman filtering and Hungarian optimal assignment is developed to realize real-time and robust trajectories tracking of fragment swarm.To reconstruct 3D motion trajectories,a global stereo trajectories matching strategy is presented,which takes advantages of epipolar constraint and continuity constraint to correctly retrieve stereo correspondence followed by 3D trajectories refinement using polynomial fitting.Finally,the simulation and experimental results demonstrate that the proposed method can accurately track the motion trajectories and reconstruct the spatio-temporal distribution of 1.0×10^(3)fragments in a field of view(FOV)of 3.2 m×2.5 m,and the accuracy of the velocity estimation can achieve 98.6%.

Single-cell transcriptome analysis uncovers underlying mechanisms of acute liver injury induced by tripterygium glycosides tablet in mice

Tripterygium glycosides tablet(TGT),the classical commercial drug of Tripterygium wilfordii Hook.F.has been effectively used in the treatment of rheumatoid arthritis,nephrotic syndrome,leprosy,Behcet's syndrome,leprosy reaction and autoimmune hepatitis.However,due to its narrow and limited treatment window,TGT-induced organ toxicity(among which liver injury accounts for about 40%of clinical reports)has gained increasing attention.The present study aimed to clarify the cellular and molecular events underlying TGT-induced acute liver injury using single-cell RNA sequencing(scRNA-seq)technology.The TGT-induced acute liver injury mouse model was constructed through short-term TGT exposure and further verified by hematoxylin-eosin staining and liver function-related serum indicators,including alanine aminotransferase,aspartate aminotransferase,alkaline phosphatase and total bilirubin.Using the mouse model,we identified 15 specific subtypes of cells in the liver tissue,including endothelial cells,hepatocytes,cholangiocytes,and hepatic stellate cells.Further analysis indicated that TGT caused a significant inflammatory response in liver endothelial cells at different spatial locations;led to marked inflammatory response,apoptosis and fatty acid metabolism dysfunction in hepatocytes;activated hepatic stellate cells;brought about the activation,inflammation,and phagocytosis of liver capsular macrophages cells;resulted in immune dysfunction of liver lymphocytes;disturbed the intercellular crosstalk in liver microenvironment by regulating various signaling pathways.Thus,these findings elaborate the mechanism underlying TGT-induced acute liver injury,provide new insights into the safe and rational applications in the clinic,and complement the identification of new biomarkers and therapeutic targets for liver protection.

Single-cell transcriptomics systematically discloses the immune-inflammatory responses of peripheral blood mononuclear cells for diabetic nephropathy

Diabetic nephropathy(DN)has become the leading cause of end-stage renal disease with high morbidity and mortality among individuals with diabetes mellitus.Although functional alterations of renal infiltrating immune cells have been reported as part of the pathological mechanism of DN,the understanding of the immune response underlying peripheral blood mononuclear cells(PBMCs)in DN remains limited.Here,single-cell RNA sequencing(scRNA-seq)was used toprofile the transcriptomic signatures of PBMCs from DN patients.

CFD/CSD-based flutter prediction method for experimental models in a transonic wind tunnel with porous wall

To predict the flutter dynamic pressure of a wind tunnel model before flutter test,an accurate Computational Fluid Dynamics/Computational Structural Dynamics(CFD/CSD)-based flutter prediction method is proposed under the conditions of a 2.4 m×2.4 m transonic wind tunnel with porous wall.From the CFD simulations of the flows through an inclined hole of this wind tunnel,the Nambu's linear porous wall model between the flow rate and the differential pressure is extended to the porous wall with inclined holes,so that the porous wall can be conveniently modeled as a boundary condition.According to the flutter testing approach for the current wind tunnel,the steady CFD calculation is conducted to achieve the required inlet Mach number.A timedomain CFD/CSD method is then employed to evaluate the structural response of the experimental model,and the critical flutter point is obtained by increasing the dynamic pressure step by step at a fixed Mach number.The present method is applied to the flutter calculations for a vertical tail model and an aircraft model tested in the current transonic wind tunnel.For both models,the computed flutter characteristics agree well with the experimental results.