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The corn threshing process is a complex process of contact interaction between thresher mechanical parts and corn ears. The paper analyzed this process with the discrete element method (DEM). A method was set up to calculate the contact forces between thresher mechanical parts (boundary) and corn ears. The conditions for corn kernels threshing were established as well. On this basis, we developed the corn threshing simulation software, and simulated the corn threshing process using the software. The simulation results are close to the actual situation, and the results verify the feasibility and effectiveness of the new method. Thus we have laid the foundation for using the DEM to analyze the corn threshing process and putting forward a novel method for the optimal design of the corn thresher.

A three-dimensional discrete element method analytic model of the corn seed metering device with combination inner-cell was established based on its 3D CAD model, and the three-dimensional particle model of corn seeds was built by using the method of combination spherical particle. The working process of the corn seed metering device was simulated and analyzed by self-developed three-dimensional CAE software. It was observed that the simulative results of the seeding performance, clearing angles and dropping angles of the corn seeds well agreed with the bench test results. A novel method for studying and designing of the corn seed metering device was put forward.

The anatomic features of left atrial diverticula (LAD) are still unclear in patients with atrial fibrillation (AF). The purpose of this study was to evaluate the prevalence and morphological characteristics of LAD in patients referred for radiofrequency transcatheter ablation of AF with dual-source computed tomography.

This paper presents a new method that use the library function offered by Pro/TOOLKIT and on account of Visual C++ development platform to achieve the recognition of Pro/ENGINEER solid model of mechanical components and extraction of geometry information. Motion attribute is set according to requirements, and analytical mode of three-dimensional discrete element method is built, therefore, Pro/ENGINEER software and the performance analysis software of three-dimensional discrete element method developed autonomously are integrated. A kind of new method and new tool is offered to three-dimensional discrete element method performance analysis and optimization design, and three-dimensional discrete element method belongs to relevant mechanical components contacted and acted with granular materials. What’s more, the correctness and effectiveness of boundary modeling method of three-dimensional discrete element method and developed software are tested and verified through real examples.

Pulmonary artery dissection is a rare but life-threatening disease, which has mainly been diagnosed at postmortem examination rather than in living patients. Herein we report an unusual case of pulmonary artery dissection involving the right and left pulmonary arteries with Eisenmenger syndrome confirmed by multidetector computed tomography CT and echocardiography in a living patient. The CT findings of our case are presented, and the utility of multidetector CT in the evaluation of pulmonary artery dissection is discussed.