RESUMO
Bouncing dynamics of a trailing drop off-center impacting a leading drop with varying time intervals and Weber numbers are investigated experimentally. Whether the trailing drop impacts during the spreading or receding process of the leading drop is determined by the time interval. For a short time interval of 0.15 ≤ Δt* ≤ 0.66, the trailing drop impacts during the spreading of the leading drop, and the drops completely coalesce and rebound; for a large time interval of 0.66 < Δt* ≤ 2.21, the trailing drop impacts during the receding process, and the drops partially coalesce and rebound. Whether the trailing drop directly impacts the surface or the liquid film of the leading drop is determined by the Weber number. The trailing drop impacts the surface directly at moderate Weber numbers of 16.22 ≤ We ≤ 45.42, while it impacts the liquid film at large Weber numbers of 45.42 < We ≤ 64.88. Intriguingly, when the trailing drop impacts the surface directly or the receding liquid film, the contact time increases linearly with the time interval but independent of the Weber number; when the trailing drop impacts the spreading liquid film, the contact time suddenly increases, showing that the force of the liquid film of the leading drop inhibits the receding of the trailing drop. Finally, a theoretical model of the contact time for the drops is established, which is suitable for different impact scenarios of the successive off-center impact. This study provides a quantitative relationship to calculate the contact time of drops successively impacting a superhydrophobic surface, facilitating the design of anti-icing surfaces.
RESUMO
OBJECTIVE@#To investigate the correlation of platelet and coagulation function with blood stasis syndrome (BSS) in coronary heart disease (CHD).@*METHODS@#The protocol for this meta-analysis was registered on PROSPERO (CRD42019129452). PubMed, Excerpta Medica Database (Embase), the Cochrane Library, and China National Knowledge Infrastructure (CNKI) were searched from inception to 1st June, 2020. Trials were considered eligible if they enrolled BSS and non-BSS (NBSS) patients with CHD and provided information on platelet and coagulation function. The platelet function, coagulation function, and fibrinolytic activity were compared between the BSS and NBSS groups. Forest plots were generated to show the SMDs or ESs with corresponding 95% CIs for each study. Subgroup analysis and sensitivity analysis were performed to explore potential sources of heterogeneity.@*RESULTS@#The systematic search identified 1,583 articles. Thirty trials involving 10,323 patients were included in the meta-analysis. The results showed that mean platelet volume, platelet distribution width, platelet aggregation rate, platelet P selectin, fibrinogen, plasminogen activator inhibitor-1 (PAI-1), thromboxane B2 (TXB2), 6-keto-prostaglandin F1alpha (6-keto-PGF1 α), and TXB2/6-keto-PGF1 α were higher in the BSS group than in the NBSS group (P<0.05 or P<0.01). Activated partial thromboplastin time was lower in the BSS group than in the NBSS group in the acute phase of CHD (P<0.01). The R and K values in thromboelastography and tissue plasminogen activator (t-PA) and t-PA/PAI-1 were lower in the BSS group than in the NBSS group (all P<0.01). No difference was found in the results of platelet count, plateletcrit, maximum amplitude, von Willebrand factor, prothrombin time, thrombin time, international normalized ratio, etc. between groups.@*CONCLUSIONS@#Increased platelet function, hypercoagulability, and decreased fibrinolytic activity were found among CHD patients with BSS.