Design and optimization of the seed conveying system for belt-type highspeed corn seed guiding device

Seeding is an important part of improving corn yield.Currently,seed guide tubes are mostly used as transport devices.But the existing seed guide tubes cannot meet the requirements or achieve the goal of fixing the seed falling trajectory.A seed collision phenomenon occurs occasionally.So,in response to the problems that the seeds and seed guide tube collide or bounce under high speed operation,which results in a lower sowing qualification rate and poor spacing uniformity,a seed receiving and conveying system comprising a belt-type high-speed corn seed guiding device was designed and optimized,to meet the needs of high-speed precision sowing operations and improve the spacing uniformity.The factors affecting the seed conveying performance were obtained by analyzing the mechanical properties of the seeds at various movement stages.These factors were the number of seed cavities between adjacent seeds,the forward speed,the height from the ground,and the installation angle.Single factor simulation experiments were conducted by selecting the paddle spacing as the test factor and using the pass rate,reseeding rate,omission rate and coefficient of variation as the evaluation indexes to investigate the influence of the paddle spacing on the seed guide performance of the device and further determine the structural parameters of the paddle belt.Orthogonal rotation combination tests of three factors and five levels were also conducted through bench testing.Then the test outcomes were optimized.The results indicated that the best results were obtained when the number of seed cavity intervals between adjacent seeds was 5.16,the installation angle was 79.40°,and the height from the ground was 31.84 mm.At this time,the qualified rate was 98.49%,the repeated sowing rate was 0.48%,the missed sowing rate was 1.03%,and the coefficient of variation was 6.80%.Experiments were used to validate the optimization results,and all of the obtained index data satisfied the criteria for accurate and quick corn sowing.The study’s findings can serve as a theoretical foundation for a belt-type high-speed corn seed guiding device optimization test.

Effects of two different glycoprotein platelet Ⅱb/Ⅲa inhibitors and the clinical endpoints in patients with intracranial Pipeline flow diverter implant

Objective:To compare the antiplatelet effect and major adverse cerebrovascular events of Pipeline for intracranial aneurysms using glycoproteinⅡb/Ⅲa antagonists(GPI)eptifibatide and tirofiban.Methods:Retrospective analysis of relevant data of patients using GPIs combined with oral antiplatelet therapy in Nanfang Hospital of Southern Medical University from December 2017 to December 2019.The study was approved by the ethics Committee of Nanfang Hospital of Southern Medical University.According to the random use of GPIs drugs,they were assigned to the eptifibatide group and tirofiban group.Basic data,platelet inhibition rates at baseline,24 h and 72 h after administration,short-term major adverse cerebrovascular events,and bleeding complications were compared between the two groups.Results:A total of 47 patients were included in this study,including 24 patients in eptifibatide group and 23 patients in tirofiban group.There was no significant difference in average age(53.75 vs.53.91 years)and body mass index(BMI)(24.39 vs.22.73 kg/m2)between eptifibatide group and tirofiban group.There was no significant difference in coagulation factor function(R),fibrinogen function(K),fibrinolysis function(EPL),comprehensive coagulation index(Cl),arachidonic acid pathway inhibition rate(AA%)and adenosine diphosphate inhibition rate(ADP%).However,the baseline level of residual platelet function MA(ADP)in eptifibatide group was significantly higher than that in tirofiban group(50.79 vs.35.29 mm,P=0.0026).There was a statistical difference in the platelet aggregation function MA(65.38 vs.62.54 mm,p=0.0442),the rate of spontaneous hemorrhagic stroke(4.3%vs.0%)and the rate of asymptomatic minor bleeding(26.08%vs.4.1%)in the two groups(P<0.05).Conclusion:Both eptifibatide and tirofiban can effectively inhibit platelets,but the effect of etifeptide is better than that of tirofiban in preventing intracranial microhemorrhage and asymptomatic cerebral infarction.

The square rod-shaped ionic polymer-metal composite and its application in interventional surgical guide device

Ionic polymer-metal composite(IPMC)is an electro-active polymer material,which has many advantages such as small size,light weight,low driving voltage,large strain,and good biocompatibility.However,the conventional sheet IPMC has the shortcoming of only bending in the two-dimensional plane,which greatly limits the application of IPMC in the field of interventional surgery.In this work,a square rodshaped IPMC with multi-degree-of-freedom motion was fabricated,and the displacement and blocking force of the square rod-shaped IPMC in different directions are measured and analyzed under the DC voltage signal.An interventional catheter was designed using the square rod-shaped IPMC in order to achieve active guidance,and a simulation experiment platform and a model of human aorta were built to successfully complete the in vitro simulation experiment of interventional surgery,which preliminarily verified the feasibility of the square rod-shaped IPMC in the field of interventional surgery.