拓扑结构

Using two kinds of representative bridgeless PFC topologies as main circuit and IR1150 as control chip, two bridgeless PFC prototypes have been designed and the EMI of the two circuits has been tested.

采用两种比较有代表性的无桥拓扑作为主电路结构，控制电路采用单周控制芯片IR1150，设计了试验样机，并对两种PFC电路的EMI进行了测试分析。

Helices membrane proteins are easier to identify and predict due to their distinctive features, and the prediction is more accurate.

由于具有明显的结构特性，α螺旋跨膜蛋白的识别和拓扑预测相对容易，预测也较准确。

The generalized fractal dimension model of openings perimeter in jointed rock mass is put forward. The relation between erecting parameters and generalized fraetal dimension of openings perimeter is analyzed. According to the fractal theory, the relation between overbreak as well as underbreak and generalized fractal dimension of openings perimeter is built.

块体理论是研究洞室超欠挖的重要工具，它是从拓扑几何学的角度来研究洞室中的关键块体，但关键块体与超挖块体之间存在区别，文中对超挖块体和关键块体之间的关系进行分析研究，应用块体理论和结构面网络模拟技术相结合的方法预测了洞室超挖块体的大小。

Two new algorithms of structural volume skeletonization and internal visibility computation are presented to support the virtual endoscope system.

提出了包含距离和拓扑信息的结构化骨架提取方法和骨架指导的内窥可见性计算方法，并将其有机地应用于虚拟漫游系统中。

In this paper, The delta wing of Mach number 0.8 at an attack angle of 21. 8 degree is simulated by our program. Then, using the visualizing program, we map the figures of space streamlines, cross streamlines near the vortex axis, three dimensional vortex lines, cloud atlas for pressure and vortex and targer of particles.

在这一章里，我们先用所建立的计算软件数值模拟了来流马赫数为0.8、攻角为21.8°的三角翼的流场，之后以拓扑分析结果做指导，研制了一套数值显示流场、旋涡结构的软件，用该软件我们绘制了跨音速三角翼背风区涡轴附近截面流线、空间流线、三维涡量线、压力和涡量云图以及粒子屏痕图。

In the transformation from surface model to solid model the open edge structure is used to realize surfaces topologic information regeneration.

在曲面模型到实体模型转换中使用了基于openedge结构的曲面拓扑信息重建技术。

The thin films with special structure have unique functions.Hydrothermal synthesis of zirconic films with different morphologies wastested on the substrate of Zr at different conditions in this thesis.

具有特殊结构的薄膜材料具有独特功能，本论文中通过不同的条件在Zr表面水热制备出不同拓扑形态的磷酸锆盐薄膜。

A composite cascade multilevel converter composed of a main converter and an accessorial one is presented which is well suited for application in high voltage situations with high performance requirements.

针对高电压、高性能功率变换场合的需要，提出了一种主从组合式多电平变换器的拓扑组合结构，具有输出波形质量高、输出电压等级高和功率转换效率高等特点。

A two-cell single-phase hybrid cascade asymmetrical multilevel converter is researched in the thesis based on AMC-AMC.

组合式不对称混合级联型多电平变换器拓扑的生成方法可以分为两种；同构组合以及异构组合结构。

The main works of this paper are as follows.First, according to the three-step method, 1-D unsteady flow model in river network is introduced. A new topological structure is presented to describe and store the topology information and data in river network ,which realises the connection between GIS and the numerical program of hydraulic calculating and turns the program into a universal one .A new formula of internal boundary conditions with double-recursion algorithm is deduced, and the relationship of recursive coefficient between imaginary channel length and non-imaginary channel length is presented ,which makes sure that the model can comprise the numerical simulation of the internal boundaries such as side pipe outflow ,barrage, slice gate and drainage pump station.

主要工作如下：(1)根据三级解法建立了一维河网非恒定流模型，并提出了一种新的数据结构来描述和储存河网拓扑信息，方便了GIS平台和数值计算程序的衔接，实现了三级解法程序的通用性；从河段方程组出发，根据虚设河段法推导出了内边界条件的双追赶法公式，指明了虚设河段的追赶系数和非虚设河段追赶系数的关系，从而使模型可以模拟集中旁侧入流、堰、闸、水泵等内边界对行洪过程的影响。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。