拓扑结构

The concept of topology optimization of truss structures with discrete variables including two kinds of variables and the relative difference quotient algorithm for discrete optimization are extended to the topology optimization of plate and shell structures composed by plate and shell elements.

将包含两类变量的桁架结构拓扑优化设计的概念及求解离散优化的相对差商法进一步推广到由板壳单元组成的板壳结构的拓扑优化，建立了包含两类变量的板壳结构拓扑优化设计模型，并采用相对差商算法进行求解。

The article makes a comparison among different types of bus, bus transmission signal and several familiar topologies of front-end converters and load-end converters. Finally, the half bridge converter with full-wave rectifier based on the high-frequency parallel-type AC bus bar is chosen as circuit structure and optimized. The working mode under different condition of the circuit is analyzed and a mathematical model is set up under continuous current mode. Simulation result is used as comparison.

通过对比不同类型的母线、母线传输信号以及各种常见的前端变换器拓扑和负载变换器拓扑，确定了基于并联型高频交流母线的半桥变换器加全波整流作为电路拓扑，并优化了电路的结构，分析了基于不同工作状态下的电路结构并建立电流连续模式的数学模型，并与软件仿真结果进行对比。

We present a SNMP-based topology discovery algorithm using direct connection theorem and simple connection theorem for judging relationship of switches in subnets. In order to in discover the map of network without SNMP, several key problems such as subnet guessing and multi-address routers are discussed in details. And then a topology discovery algorithm based on primitive protocols is presented. We also deeply study some routing protocols such as OSPF and BGP and propose a routing-protocols-based algorithm for topology discovery.

基于判断交换机互联的直接连接定理和间接连接定理，提出了一种完整的基于SNMP的拓扑发现算法；详细讨论了子网获取、多址路由器处理等关键问题，针对不同的网络环境给出了相应的解决方案，并以此为基础提出了一种基于通用协议的拓扑发现算法；在对OSPF，BGP等网络路由协议进行分析的基础上给出了一种基于路由协议的拓扑发现算法，并设计了一个自上而下的拓扑发现框架结构。

Furthermore, the information dissemination of several topologies is analyzed theoretically, and the statistical properties of canonical topologies and varying neighborhood topology are analyzed from graph theory.

针对传统粒子群优化算法中全连接型拓扑和环形拓扑的特点，引入了一种粒子群信息共享方式——多簇结构，进而基于多簇结构提出了动态可变拓扑策略以协调动态概率粒子群优化算法的勘探和开采能力，并从理论上分析了最优信息在各种拓扑中的传播，同时从图论角度分析了几种经典拓扑以及动态可变多簇结构的统计特性。

This paper firstly introduces the point set of topology theory, enumerating all kinds of topology relations which have practical application value.

首先介绍了点集拓扑理论，归纳了有实际应用价值的各种拓扑关系，分析了拓扑模型中的最基本拓扑元素和空间实体的关系；然后提出了一种要素类的拓扑构建方法，其算法以MAPGIS7.0空间实体的结构为依据，主要体现要素分裂的思想。

Then, a new structural topology optimization method is proposed based on thelevel set method. The structural topology configurations are concentrated to handle the structural boundary.

另一方面，论文给出了一种基于Level Set方法的结构拓扑优化设计方法，将结构拓扑构形集中在拓扑边界的处理上。

Based on the ICM (independent continuous topological va riables and mapping transformation) method, a unified sm ooth model with weight objective and stress constraints was established for the topology optimization design of continuum structures.

基于独立连续拓扑变量及映射变换的拓扑优化方法应用于连续体结构，建立了统一的以重量为目标、考虑应力约束的连续体结构拓扑优化模型。提出基于综合评价的高效单元删除准则及算法。

Other types of topologies may be utilized.

也可以利用其他类型的拓扑结构。

First, the principle and the topologies of sin...

首先，针对单相DC/AC变换器，分析了它们的主电路拓扑结构、工作原理以及脉宽调制方式。

The complementary cumulative distribution and correlation of the topological structure are analyzed revealing that the network presents small-world property.

文中分析了该网络拓扑结构的补累积分布以及相关性，从其统计特性可以得出该网络具有小世界特性，揭示出结点的点权以及其邻居的平均点权之间具有正线性相关，同时结点的权重平衡度服从幂律分布。

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。