拓扑结构

Relative study indicate that current doubler rectifier is misfit for high-voltage low-current apply.so This paper proposes a auxiliary net ZVS PWM full-bridge three-level converter, its" improved topology structure and its"topology family in different controlling mode. The principle of these converter is analyzed in detail. Simulation results verify the effectiveness of the proposed converter.

为了进一步简化辅助网络的结构，并解决轻载时，超前桥臂实现软开关困难的问题，提出了一种新型宽负载范围辅助电感ZVS PWM三电平全桥直流变换器，它在基本拓扑结构的基础上只需增加一个辅助电感，利用辅助电感的能量就可以实现宽负载范围内所有开关管的软开关，详细分析了该变换器的工作原理，进行了参数设计和仿真验证。

A 2-D coded GA is proposed to design the matching network composed of lumped components. The topology and component parameters of the matching network are optimized simultaneously. The network optimized by employing the 2-D coded GA shows better frequency response compared with the network synthesis method and the real frequency method. The thesis also employs the GAs to microwave measurement.

为了解决宽带匹配网络的设计问题，提出了一种二维结构的编码方案，采用这种形式的编码同时对网络结构和元件参数进行优化，成功地设计出性能优良的匹配网络，通过与综合法、实频法的设计结果相比较，表明遗传算法设计出的匹配网络性能更优，特别是在寻找新的网络拓扑结构方面，遗传算法具有更大的优势。

This project is development of a MIS system of a hotel.

在系统的总体设计部分，给出了系统的网络拓扑结构、软件地C/S结构、连锁酒店之间的数据交互情况，并给出了客服中心的设计方案。

From the practical point of view,it notedly expounds the network topology design,network hierarchy,system design,IP planning,division of subnet VLAN,security design,equipment selection and cabling system as well as relative technologies,aimed at constructing a advanced and practical campus network.

从实用的角度重点论述了校园网的拓扑结构设计、网络层次结构、系统总体设计、IP规划、子网VLAN划分，安全设计、设备选型以及综合布线系统等相关技术，其目的是要建设一个先进、实用的校园网。

The space quadrature vector oriented control can decouple between output current and frequency of the inverter by Park transformation, which guarantee the quite high accuracy of the 90 degree phase angle between the two-phase output current that supply for two phase electromagnetic stirrer in quite low frequency.

提出了一种基于空间矢量定向的二相电磁搅拌器逆变电源的结构和控制策略，该逆变器采用六桥臂式主电路拓扑结构，逆变器的第三相桥臂与两相电磁搅拌器的中点相连。

Structures of the skin friction lines appearing on a prolate spheroid in l aminar and turbulent flows were investigated and compared by using an improved o il-flow visualization technique.

用改进的油流显示法研究和对比了层流和湍流状态下绕椭球流动的表面摩擦力线结构。实验中观察到，椭球表面摩擦力线在层流和湍流状态下具有不同的拓扑结构。

The method includes the following steps: firstly, a spherical neighborhood of present sample points is established by using the geometric spherical-modelling theory and all the sample points contained in the spherical neighborhood are adopted as candidate neighbor points, thus not only preserving the effectivity of the dimension reduction capability when data sets are sparse but also getting the advantages of low-sensitivity to isolated points and good stability of the preserved topological structure; then a data relevance matrix more matching semantics can be obtained by relevance measurement based on route clusters to update the candidate neighbor points in the spherical neighborhood and optimize the regular neighborhood space of the present sample points, thus improving the phenomenon that the dimension reduction of sample sets provided with folded curved faces is apt to suffer the integrated-structure distortion in case of heterogeneous data distribution.

首先利用几何开球原理建立当前样本点的球状邻域，将包含在球状邻域内的所有样本点作为候选近邻点，不但能够保持在数据集稀疏情况下的降维性能的有效性，而且具有对孤立点敏感性不高、保留拓扑结构稳定性好的优点。然后利用基于路径聚类的相关性度量得到更符合语义的数据相关性矩阵，用来对球状邻域内的候选近邻点进行更新，优化当前样本点的规则邻域空间，改善了当数据不均匀分布时在带有折叠弯曲面的样本集上降维容易出现整体结构扭曲的现象。

All shared files in all Hash table,and the location information and routing information are storaged at the same time while the wireless network topology is set up.The problem of positioning query and download among shared file are solved by the tree logic structure among the nodes.

所有共享文件采用全分布哈希表，在无线网络拓扑结构建立的同时存储和保留位置信息以及路由信息，通过节点间的树形逻辑结构解决共享文件的定位查询和下载问题。

The description of network delays including characteristics and effects are also covered and the uniformed mathematic models for NCSs with four different structures are derived. Furthermore, the controller basing on state prediction and compensating time delay is designed. Sufficient and necessary stability conditions for systems with different transmission policies such as perfect transmissions, delayed transmissions and time-varying transmissions are obtained as simple eigenvalue tests of certain test matrices. And in the end, effects of model error over maximum communication interval are analyzed. Numerical examples show the feasibility and efficiency of the proposed methods.

首先介绍了网络控制系统中数据包的传输情况以及基于模型结构方法的基本思想，并针对四种不同拓扑结构的控制网络分析了网络时延的性能，进而给出了统一的数学模型；然后，提出了基于状态预测的具有时延补偿功能的状态反馈控制器的设计方法，并针对完美传输、延时传输及时变传输三种数据传输策略，分别研究了控制系统的稳定性问题；最后分析了模型误差对最大通讯间隔的影响；仿真结果表明了设计及控制方法的正确性和有效性。

The structure of its four major parts, which includes the control computer of the master station, the loop select circuit, the slave station and the power section of the system was introduced.

给出了适应远程多分站测控系统的拓扑结构，并对其四个主要部分：主站控制计算机、环路控制器、分站及系统电源的结构分别进行了介绍。

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。