三维

From the governing equations satisfying the balance between pressure gradient force, inertial centrifugal force and viscous force, the threedimensional velocities of tornado are obtained, and then its funnel structure is depictured theoretically. It shows that the funnel structure consists of vertex flow and jet flow.

本文用气压梯度力、惯性离心力、黏性力三力平衡的柱坐标下的大气动力和热力学方程组，求龙卷风的三维速度场，从理论上绘制出龙卷风的三维漏斗型结构。

The effed Of three-dimensional perturbed velocities and three-dimensional perturbed current densities on the beam-wave interaction of plasma-filled dielectric Cherenkov maser is analysed by use of the self-consistent linear field theory without considering the effect Of the longitudinal guided magnetic field.The dispersion relation and the Simultaneous condition of the beam-wave interaction are derived. It is clearly shown that the instability of the interaction results from the coupling of the TM mode in t...

在无引导磁场的作用下，利用自洽线性场理论，分析了电子的三维扰动速度和三维扰动电流密度对填充等离子体的介质切伦可夫脉塞注波互作用的影响，导出了注波互作用的色散关系和同步条件，所得关系清楚地表明，其工作用不稳定性是由填充等离子体的介质筒慢波波导中的TM模与电子注模通过电子注耦合所致，并求得了电子注引起的频偏和波的增长率。

In the last years, CAD technology has been growing up from an auxiliary tool to an independent technology in all kinds of fi elds. It is intend to be intelligent, integrated and internet. Especially in 3D technology, it will be a main stream rapid in the modern times.

近年来，CAD 技术从最初的平面辅助绘图工具，迅速向智能化、三维化、集成化和网络化的方向发展，其中三维技术以其突出的优越性，迅速成为CAD 业界的发展主流。

Methods to 15 Han face bone fracture sufferer line thin layer continuous after scan, make use of the work station carry on empress the picture a processing and choose to use variety software technique, many flat surface reconstruction, the 3D surface cover up manifestation(3 D-SSD) and capacity reappear method etc. reorganization observation, reconstruction Han face the 3D image of the bone fracture, acquire the best picture photograph, and with CT crossing the picture carry on more analysis.

对15例颌面部骨折患者行薄层连续扫描后，利用工作站进行图像后处理，选用多种软件技术，多平面重建、三维表面遮盖显示（3D-SSD）及容积再现法等重组观察，重建颌面部骨折的三维影像，获得最佳图像照片，并与CT横断图像进行比较分析。

In the establishment process of three dimensional visualization model, we proposed the contour line drill hole - multi-layer face mold method.This method which improves Delaunay triangulation, is suitable for the random polygon triangulation and is easy for computer to realize. It makes three dimensional stratum visualization model of picking area realized under the limited condition.

在三维地层可视化模型的建立过程中，提出了基于等高线的钻孔—多层面模型方法，这是一种对现有的Delaunay三角剖分方法进行了改进，该方法适用于任意多边形的三角剖分，且易于计算机实现，使采区的三维地层可视化模型在有限条件下也能够实现。

The third, the 3D design and assembling technology based on UGII was investigated in this paper. At last, the paper studied the CAM application technologies, directly created 3D model, including the creation method of cutter location file directly from the 3D model, the NC post processing, etc. The method of generating user final feature lib used in refrigerator mould based on UG II was also discuss in this paper, several examples for lib creation was given as an illustration.

探讨了基于UGⅡ软件的三维产品设计技术、装配设计技术；最后，探讨了从三维产品模型直接生成刀位源文件，并进行数控加工的CAM技术的实现，生成数控加工刀位源文件和NC加工后置处理程序；探讨了基于UGⅡ软件的冰箱吸塑模的用户特征库的建立，并给出了建库的几个实例。

The distributions of velocity, velocity gradient, shear stress, clongation stress, first normal stress difference and pressure of the flow of a power-law fluid in the profile die were analyzed. It indicates that for a power-law fluid only after a few iterations a good convergence can be reached, even though in the case of high extrusion velocity.

详细分析了聚合物口模挤出三维计算机模拟研究中的若干关键技术问题，如对异型材结构特点的分析、边界条件的确定、初始速度场的自动生成、罚数的求取、粘弹性流动模拟中的高We数问题、三维挤出胀大的自由界面更新等。

The simulation results of the cylinder-block model were given in the article, consistent with that of Middlemen"s. It was shown that the block part could improve the uniformity of the flow distribution. The analysis of the flow field of some materials with different power-law factor in the die designed by Mckelvey was close to that of Mckelvey"s. It was shown that the flow distribution was uniform in the die that can producesheets with 1200mm in width. During the analysis the flow channel was divided into several parts to get the details about the fluid flow in each area. A conclusion was drawn after analyzing the influence of the die pressure on the flow distribution, that the higher pressure is good for the output and bad for the uniformity of the distribution. Simulation of the die applying the cylindrical main runner showed the fact that when the cylinder replaced the cone the change of uniformity was trivial. The uniformity of the non-block flow channel was so poor that the block in the proper position of the die channel was necessary. The project of the die for the wider sheet was put forth, and the analysis of the fluid flow in the die was shown.

本文模拟了圆柱管缝隙流模型的三维流动场，得到了与Middlemen结论一致的流动均匀性，并通过模拟直观地展示了采用阻尼块可以改善挤出均匀性的现象；分析了多种幂率指数的流体在Mckelvey等人设计的流道模型中的流动分布，得到了与Mckelvey的分析结果接近的压力降和流量偏差；本文建立了1200mm幅宽机头流道的三维有限元模型，并逐个分析各个区域和多个截面的流动分布状况，由此揭示了1200mm幅宽L-型机头流道内的流北京化工大学硕士学位论文动分布基本均匀，并在分析了机头压力对于挤出流动分布的影响后得出结论：较高的机头压力可以获得较大的产量，但是不利于物料均匀分布；模拟了采用圆柱管主流道时机头流道内的流动分布，得出结论：主流道由圆锥管改为圆柱管时对流动均匀性影响不大，通过设置适当的阻尼仍然可以达到挤出平衡；模拟了两端进料式圆柱管无阻尼流道的流动均匀性后得到结论：两端进料式无阻尼结构的流动均匀性较差，宽机头中仍然有必要设置阻尼块；确定宽幅机头流道的基本方案，并设计了一种宽幅防水卷材挤出机头流道的结构，通过流动模拟表明该种结构的流动均匀性较好；考察了宽幅机头对于不同厚度片材的挤出适应性，得到结论：当生产不同厚度的片材时，阻尼块高度需要调整。

In this dissertation the"Penalty"finite element method was employed to compute the velocity of the three-dimensional flow of power-law fluid in a profile die. In order to decrease the needed computer memory and raise the stability of numerical simulation, a set of decoupled methods such as PFEM, pseudo-body force method and transformation of momentum equation to the elliptic equation was developed to establish the general finite element equations to compute the distributions of velocity and viscoelastic stress of the three-dimensional viscoelastic flow of the Phan ThienTanner fluid in a profile die. During numerical simulation of the extrudate swell of the PTT fluid, the flow in the die and out of the die was analyzed separately, which demands less computer memory. The key techniques used in numerical simulation of the three-dimensional extrusion from dies such as decision of boundary conditions, creation of initial velocity field, selection of penalty factor, high Weissenberg number problem , regeneration of the free surface were studied in detail.

中文题名聚合物异型材口模挤出三维流动研究副题名外文题名 Study on three-dimensional flow of polymer melts during the process of profile extrusion from dies 论文作者涂志刚导师柳和生包忠诩教授学科专业材料加工工程研究领域\研究方向学位级别博士学位授予单位南昌大学学位授予日期2001 论文页码总数148页关键词挤出成型聚合物材料挤出口模聚合物异型材馆藏号BSLW /2003 /TQ320 /9 本文建立了求解挤出口模内幂律流体流动速度场的通用三维罚有限元模型；对于非线性粘弹性的Phan Thien-Tanner流体，为了降低模拟计算对计算机硬件的要求，并使模拟计算更加稳定，采用了一种去耦算法，包括罚有限元方法、拟体力方法和动量方程的椭圆类方程转化方法，并建立了求解速度场和粘弹性应力场的总体有限元方程；对于PTT流体的挤出胀大问题，提出了挤出胀大熔体口模内外分离模拟法，这样可以显著降低数值模拟对计算机硬件的要求。

By the import of indirect differential frequences conception, numeric differential frequences method with improves the absolute measurement distance 1 times is present.

通过将间接差频测距概念引入连续光源三维成像系统，提出了数值差频三维测距法，将绝对测距量程提高到原来的3倍。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。