基于3DWidgets的三维人机交互平台的设计与实现

随着人机交互技术的不断发展,对三维人机交互的支持在三维图形软件中占有越来越重要的地位,而在医学影像处理与分析领域,它对于更方便、准确地使用可视化的结果辅助医生进行诊断具有重要意义。该文针对医学影像处理与分析领域中三维交互的需求与特点,设计并实现了一个基于3D Widgets的三维人机交互软件平台,包括以3D Widgets为核心的交互框架、各功能模块以及一些实用的Widgets的设计和实现,并给出了一组应用实例。其最终目的是为医学影像处理与分析领域提供一个灵活可靠和可扩展的三维交互平台。

AN ANALYSIS ON LARGE-SCALE AIR-SEA INTERACTIVE LINKAGES BETWEEN THE TROPICAL INDIAN OCEAN AND THE PACIFIC OCEAN DURING ENSO EVENTS

By utilizing a 3-D atmospheric circulation resolving method, the authors studied the air-sea interactive linkages between the tropical Indian Ocean and the Pacific Ocean in 1979-2008 E1 Nifio-Southern Oscillation （ENSO） events. Their findings showed that evident 3-D gear-coupling characteristics existed in the 1979-2008 ENSO events. Their resolving analyses also suggested that the general circulation showed stronger and wider sinking motions over the eastern Indian Ocean-western Pacific during the mature phase of 1979-2008 ENSO events, compared with the vertical velocities from the U.S. National Centers for Enviornmental Prediction （NCEP） reanalysis data. With their 3-D analysis method, the vertical velocity was resolved by two components, i.e. zonal and meridional components. It was found that the zonal component of the vertical velocities showed a strong sinking motion while the meridional components showed an upward motion during the prevailing phases of the ENSO events. In the tropics, the zonal component of the vertical velocities was found greater than the meridional component, reflecting the dominant characteristics of the vertical velocity, and the overall outcomes showed a strong sinking motion, although the two components also partially offset each other in the processes. Compared with the vertical velocities from NCEP reanalysis, the vertical motions calculated with the 3-D resolving analysis method demonstrate some advantages.

基于CATIA的心墙堆石坝三维可视化交互系统

目前大坝施工仿真建模中多是基于Geographic Information System(GIS)或3DS MAX软件构建的施工场景,其三维模型存在精度不高,不易修改,相似模型也不能重复利用等问题。本文将CATIA引入心墙堆石坝施工仿真建模中,即利用CATIA的三维建模技术构建了心墙堆石坝的三维施工场景。关键技术包括骨架设计技术、参数化技术、知识工程技术和设计过程模块化技术,并通过三维数字建模来模拟整个建筑物的信息。以某心墙堆石坝为例,建立了基于CATIA的心墙堆石坝施工仿真系统平台,实现了基于Brower/Server(B/S)的堆石坝施工场景的远程交互,可为堆石坝施工管理提供理论与技术支持。

交互式三维对象建模方法研究与实现

论文设计了一种交互式三维对象建模方法,为非专业三维应用开发人员提供了一个友好的三维图形开发应用平台。研究了三维对象模型的概念模型和逻辑模型,分析了三维对象模型拓扑关系的存储方式和查询方式;提出了关系模型,设计出三维对象模型与关系模型间的相互作用方式;采用模型库保存常用的基本模型和关系模型,用户也可按需求自定义对象模型和关系模型,并扩充模型库,使得模型具有较好的可重用性;结合OSG三维图形引擎,验证了提出的交互式三维对象建模方法的可行性。

A generalized variational principle and theoretical model for magnetoelastic interaction of ferromagnetic bodies

The quantitative analysis shows that no theoretical model for 3-d magnetoelastic bodies, in literatures to date, can commonly simulate two kinds of distinct experimental phenomena on magnetoelastic interaction of ferromagnetic structures. This makes it difficult to effectively discribe the magnetoelastic mechanical behavior of structures with complex geometry, such as shells. Therefore, it is a key step for simulating magnetoelastic mechanical characteristics of structures with complex geometry to establish a 3-d model which also can commonly characterize the two distinct experimental phenomena. A theoretical model for three dimension magnetizable elastic bodies, which is commonly suitable for the two kinds of experimental phenomena on magnetoelastic interaction of ferromagnetic plates, is presented by the variational principle for the total energy functional of the coupling system of the 3-d ferromagnetic bodies. It is found that for the case of linear isotropic magnetic materials, the magnetic forces obtained by this model include not only the body magnetic force which is the same as that got from the magnetic dipole model, but also a distribution of the magnetic traction on the surface of the magnetizable body. And the value of the traction is equal to the jumping one of the Faraday electromagnetic stress on the two sides of the surface, which does not appear in any model, such as magnetic dipole model and axiomatic model.

Design of a Sector Cascade Applied in the Middle Stage of a Compressor Test Rig

A compressor test platform was designed in the purpose of easy assembly and cost-saving tests.New design concepts were firstly used on the test platform and iterative revisions were conducted to verify the effects,which decrease the risk of applying to the full annulus directly.The platform was a sector cascade that can be inserted into an otherwise full stator annulus,with a set of exchangeable endwall casing and blades manufactured by 3-D printing.The platform can create an operating condition which is closer to engine-realistic flow conditions than traditional cascade tests.The flow field of the prototype stator was tested in detail at the operating point and showed some flow defects in the tip region,and then three design plans were conducted to experimentally investigate which design concept could improve the blade tip flow.The concept of casing endwall profiling was the most effective one which markedly depressed the separation of the tip region and decreased the total pressure loss coefficient.The test results show that the design of the test platform was successful and promising,which could be used to conduct more researches on the flow mechanism of the middle stage.

FSI simulation of dynamics of fish passing through a tubular turbine based on the immersed boundary-lattice Boltzmann coupling scheme

The anadromous fish can pass through turbines of run-of-the-river hydropower stations to reach the downstream watershed, but their mortality is significant because of the complex turbine structure, the fast-rotating runner, and the special flow patterns. Numerical simulations of the dynamics of fish passing are a challenging task, because the fish motion in the turbines involves a strong fluid-structure interaction (FSI). In this paper, the 3-D immersed boundary-lattice Boltzmann (IB-LB) coupling scheme is proposed to treat the FSI between the water and the fish. The process of one fish and three fish passing through a tubular turbine is simulated on a graphics processing unit (GPU) platform. The fish motion postures (translation and rotation), the fish body pressure distributions and histories are analyzed, and the results are consistent with the previous studies. This paper presents the IB-LB models, the simulation procedures, the specific treatments, and related results, to demonstrate the effectiveness of the IB-LB coupling scheme in simulating FSI problems and its application prospects in developing fish-friendly turbines.