Visualization of 3-D Field of Explosion

In order to visualize the 3-D field of explosion and describe the complex physical phenomena of explosion, the 3-D data resulting from numerical simulation by 3-D multi-material in cell (MMIC), and the application of volume visualization is explored, based on the characteristics of explosion and shock. Based on this, a visualization system for 3-D explosion--ViSC3D is designed. Approaches for the visualization of 3-D field of explosion are presented. The algorithm and the functions of ViSC3D are also presented. ViSC3D is thus a useful tool to observe and analyze either the full picture or the details of a 3-D field of explosion, that are difficult to observe and analyze directly. With ViSC3D, the field of explosion between the hill slopes is visualized. The cutaway views and 2-D slices are also given. The full picture and partial details of 3-D field of explosion can be observed clearly. Furthermore, ViSC3D can be used to visualize other similar 3-D data fields.

3-D velocity structure of P wave in the upper mantle beneath southwestern China and its adjacent areas

3-D velocity structure of P wave in the upper mantle beneath southwestern China and its adjacent areas (10°N [similar to] 36°N, 70°E [similar to] 110°E) down to the depth of 400 km has been studied by using 80 974 P-wave first arrival times recorded at 165 stations from 7 053 events both within the studying areas, selected from the ISC bulletin and the Bulletin of China and NEIC fundamental seismic network. With a resolution of grid spacing of 2°×2°, the velocity heterogeneity on the horizontal profile is obvious though it attenuates with the depth increasing. On the vertical profiles of velocity along the latitude of 16°N and 24°N, the collision and extrusion of India plate to Eurasia plate is displayed, and a remarkable velocity difference between India plate and Eurasia plate is shown. In the vertical profile along the longitude of 90°E, the subducting of India plate northward beneath Eurasia plate (Tibet plateau) is also obvious. On the horizontal profile at the depth of 90 km, a slow velocity stripe from Myitkyina, Myanmar to Donghai, Vietnam seems to be related to Honghe fault belt. An illustration method of describing the resolution more directly and exactly has been proposed and utilized in this paper.

In-situ three-dimensional visualization of dynamic tension deformation in ferrite stainless steels

An improved three-dimensional （3-D） experimental visualization methodology is presented tor evaluating the fracture mechanisms of ferritic stainless steels by in-situ tensile testing with an environmental scanning electron microscope （ESEM）. The samples were machined with a radial notched shape and a sloped surface. Both planar surface deformation and sloping surface deformation-induced microvoids were observed during dynamic tension experiments, where a greater amount of information could be obtained from the sloping surface. The results showed that microvoids formed at the grain boundaries of highly elongated large grains. The microvoids nucleated in the severely deformed regions grew nearly parallel to the tensile axis, predominantly along the grain boundaries. The microvoids nucleated at the interface of particles and the matrix did not propagate due to the high plasticity of the matrix. The large microvoids propagated and showed a zigzag shape along the grain boundaries,seemingly a consequence of the fracture of the slip bands caused by dislocation pile-ups. The final failure took place due to the reduction of the load-beating area.

三维可视化技术及其在层序地层分析中的应用

油田开发工作中面临的许多复杂地层对比问题对层序地层学理论和应用技术提出了更高的要求 ,而三维可视化技术是一种基于三维体的真三维计算机解释技术 ,利用该技术可对三维地震数据直接解释地层的构造、岩性及沉积特征 ,尤其在分析地层的沉积体系方面可显示出其巨大的优势。本文在研究某油田复杂的层序地层关系时 ,将传统的层序地层分析方法与三维可视化技术相结合 。

港浅8-6井区河道砂体储层预测的综合研究

在对多种方法储层预测结果对比的基础上,采用三维可视化地震解释软件对大港油田港浅8-6井区明化镇组河道砂体进行了预测,提出了河道砂体三维可视化地震解释储层预测方法。其思路是:利用三维可视化解释软件的可视化解释功能,快速扫描数据体,寻找河道砂体,砂体与构造背景或与井点含油气信息结合寻找含油气潜力砂体,然后对潜力砂体进行预测和描述。该方法对于港东开发区平面上快速变化、纵向上频繁叠置的明化镇组曲流河薄砂体的预测取得了较好的效果,预测的NmⅢ4-2油层砂体已被完钻的7口新井所证实。三维可视化地震解释储层预测法可实现油层厚度仅为3．5-6．6 m的河道薄砂体的精细描述。

ASSESSMENT OF MILITARY AIRFIELD OBSTACLE FREE SPACE BASED ON GIS

A mathematical model of obstacle limit surfaces for military airfield obstacle free space is established through airfield obstacle free space analysis.Based on the model,triangle mesh elevation model of military airfield obstacle free space is built by using the software-ArcGIS,and the 3-D display result is obtained.It is convenient to evaluate military airfield obstacle for superimposing digital elevation model（DEM）with military airfield topographic map.Thus it improves the efficiency greatly.It lays the foundation for the application of geographic information systems（GIS）in the management of military airfield obstacle free space.

Experimental research on nonlinear characteristics of natural convection in a 3-D shallow cavity

Experiments were conducted to study the temperature field,flow field,3-D characteristics and self-sustained oscillation of the natural air convection in a 3-D shallow cavity which was heated from underneath. The experiments were conducted by the methods of laser holographic interferometry photography and smoke visualization. To ensure the temperature of both plates to be constant and the accuracy of laser interferometer,the instrument was calibrated and error has was analyzed. The results showed that the flow field was stable at lower Rayleigh numbers. When the Rayleigh number increased,the flow field became instable and the isotherms distorted. The rolls merged at Ra=12500 and formed along both axes when Ra was over 18500. The air rose from the middle and descended in the circumference while the flow field and heat transfer converted to 3-D characteristic from 2-D characteristic. When the Rayleigh number increased,the flow field became more instable. The rolls became irregular and time dependent when Ra≥Rac(=30500) ,which is nonlinear. When lateral walls were heated or cooled,the rolls merged along the long axis and two rolls formed along the short axis. Three rolls formed occasionally in the process.

Characteristics of a Terrain-Following Sigma Coordinate

This study quantifies the main characteristics of a terrain-following, G-coordinate through mathematical analyses of its covariant and contravariant basis vectors as well as the vertical coordinate of σ. A 3-D schematic of the σ-coordinate in a curvilinear coordinate system is provided in this study. The characteristics of the basis vectors were broken down into their ＂local vector charac- teristics＂ and ＂spatial distribution characteristics＂, and the exact expressions of the covariant; in addition, the con- travariant basis vectors of the G-coordinate used to eluci- date their detailed characteristics were properly solved. Through rewriting the expression of the vertical coordi- nate of G, a mathematical expression of all the cr-coor- dinate surfaces was found, thereby quantifying the so- called terrain-following characteristics and lack of flexi- bility to adjust the slope variation of G-coordinate sur- faces for the classic definition of G. Finally, an analysis on the range value of the vertical coordinate demonstrated that the general value range of G could be obtained by eliminating the G-coordinate surfaces below the Earth＇s surface. All these quantitative descriptions of the charac- teristics of G-coordinate were the foundation for improv- ing the G-coordinate or creating a new one.

一种井眼轨迹不确定性方法的可视化研究与应用

随钻测量工具在定向钻井过程中的应用已经较为普遍,为了能更好的应用随钻测量工具,基于其测量原理,针对测量误差源展开讨论,在ISCWSA误差模型的基础上,讨论井眼轨迹不确定性计算方法。以Python作为编程开发语言,进行算法分析和设计,并给出了其建模过程,实现了井眼轨迹可视化及对井眼轨迹不确定性的三维误差椭球的可视化分析,可以直观的看出井眼轨迹误差的大小及井眼轨迹前进趋势,为井眼防碰及井眼轨迹控制等提供了很好的理论参考。

Technical features in the Portal to CADAL

China-America Digital Academic Library Project (CADAL) is a collaborative project between universities and institutes in China and the USA, which aims to provide universal access to large scale digital resources and explore the ways of applying multimedia and virtual reality technologies to digital library. The distinct characteristic of the resources in CADAL is that it not only contains one million digital books of different languages, but also contains Terabyte level multimedia resources (image, video, and so on), which are utilized for education and research purposes. So, in the Portal to CADAL, both the traditional services of browsing and searching of digital books, and the services of quickly retrieving and structurally browsing of multimedia documents should be provided. In addition, the services of visual presentation of retrieved results are required too. In this paper, the underlying novel multimedia retrieval methods as well as visualization techniques, which are used in the CADAL portal, are investigated.

Experimental Investigation of the Three-Dimensional Flow in an Annular Compressor Cascade at Large Incidence

This paper presents a detailed experimental investigation concerning the influence of blade loading (incidence) on the three-dimensional flow in an annular compressor cascade.The data are acquired at four incidence angles under low Mach number and low Reynolds number conditions.Experimental techniquss include the oil-film visualization on the profile and the endwall surfaces,the laser-sheet visualization of the flow field inside the blade passage,and the measurement by radial-circumferential traveress using a seven-hole probe.The behavior and nature of the three-dimensional flow with severe separations inside the blade passage and at the exit are obtained.The distributions of the total pressure loss,static pressure,velocity and outflow angle are also given. These results are valuable for establishing the physical model of the three-dimensional complex flow in axial compressors and for examining the computational procedures.

Forest visualization at multiple scales for management and planning

In this study forests were visualized at various scales by placing individual trees into a forest with realistic sizes and densities. Tree images were used from two sources: high quality field photos and images created using graphic design software. The terrain, species composition, and tree sizes and density from forest inventory were all represented in GIS data format. In addition, non-tree objects and features that are essential for close-to-reality visualization were combined with the tree images in a 3-D visualization software package. We further portrayed stand level effects by animating a simulated fly-through of a forest. To visualize temporal change, a case study of four different forest patches was animated. The advantages of this approach comparing to other visualization approaches are: (1) it represents the forests with realistic individual tree images; and (2) it maintains both visual and informational realism in a forest viewable from within-stand to landscape scales. Thus, this approach is realistic in two aspects. First, it is almost as realistic as a photograph, and secondly, its information content is actual forest composition, density, and height.

Exploring the reasons for the seasons using Google Earth, 3D models, and plots

Public understanding of climate and climate change is of broad societal importance.However,misconceptions regarding reasons for the seasons abound amongst students,teachers,and the public,many of whom believe that seasonality is caused by large variations in Earth’s distance from the Sun.Misconceptions may be reinforced by textbook illustrations that exaggerate eccentricity or show an inclined view of Earth’s near-circular orbit.Textbook explanations that omit multiple factors influencing seasons,that do not mesh with students’experiences,or that are erroneous,hinder scientifically valid reasoning.Studies show that many teachers share their students’misconceptions,and even when they understand basic concepts,teachers may fail to appreciate the range of factors contributing to seasonal change,or their relative importance.We have therefore developed a learning resource using Google Earth,a virtual globe with other useful,weather-and climate-related visualizations.A classroom test of 27 undergraduates in a public research university showed that 15 improved their test scores after the Google Earth-based laboratory class,whereas 5 disimproved.Mean correct answers rose from 4.7/10 to 6/10,giving a paired t-test value of 0.21.After using Google Earth,students are helped to segue to a heliocentric view.