基于OPNET Modeler的扩展WLAN仿真及实测研究

扩展的无线局域网(Extended WLAN)是网络终端通过接入点(AP)与WLAN外的节点通信并进行相互之间连接的网络.文章使用OPNET Modeler对扩展的WLAN进行了研究和仿真.在现实环境下搭建了WLAN并使用测试软件NetIQ Chariot和Network stumbler对网络进行实测.从理论与实践上得出对比,较全面分析了WLAN的性能.     

自抗扰控制思想探究

韩京清先生1989年的《控制理论: 模型论还是控制论》一文, 反映了他对控制科学与工程实践的深刻理解和整体把握, 为日后自抗扰控制技术(active disturbance rejection control, ADRC)的创建和发展奠定了基础. 可以说它既是源头活水, 又是深入理解自抗扰控制的必经之路. 本文对控制论的范式、本质问题和基本原理进行了进一步的梳理和反思, 探讨了自抗扰控制思想的内涵和意义, 目的是为自抗扰控制技术和理论的进一步发展做好铺垫.     

差动轮系指南车的设计与分析

为了满足科普和教学的需要,用虚拟样机技术对我国古代传说中的指南车进行了设计与分析。机构中使用齿轮差速器对小车的转向进行补偿,使得导向杆相对于地面的转动速度始终为0,实现了实时指南的效果。仿真分析和实物制作都取得了成功,证明了结构的合理性。设计的指南车结构简单,传动件较少,易于观察和理解,适合科普和教学的需要。     

Tutankhamun's chariots: secret treasures of engineering mechanics

The Tutankhamun‐class chariot is the earliest high‐performance machine, most likely developed via racing and thoughtful mechanistic modelling and testing, and made with exquisite craftsmanship. The complex suspension system of springs and dampers comprises simple elements that are useful by chance, and also some well‐designed and expensive components and subassemblies for advantages in structural dynamics and ride quality. These chariots' spokes and joints have aircraft‐like damage tolerance, and are more sophisticated than those of any veteran car with wooden wheels. A substantially better overall design with the ancient materials of construction is difficult to visualize even if we apply our knowledge and computerized methods. This makes the Egyptian chariot an excellent example of original and advanced design, and a formidable challenge in further engineering investigations aimed at a full understanding of the ancients' achievements.     

与装甲战车服役期相匹配的维修策略

该文通过计算机仿真,提出了与装甲战车服役期相匹配的一种维修策略.根据实际数据,利用威布尔分布,得到使维修费用速率最小的最佳维修时间序列.     

普通战车车轮微多普勒特征分析与提取

本电路首先将220V交流电变为12V直流电压来为整机供电,并应用气敏传感器MQ-2把瓦斯气体浓度这一非电量转换为电信号,再经由运算放大器μA709将该信号与门限电压比较,由电压比较器转化为数字信号并控制由LM555数模集成电路组成的双稳态触发电路最后应用继电器来控制报警电路和通风设备,从而实现报警。     

淮安运河村战国墓木雕鼓车的保护和修复

淮安运河村战国墓木雕鼓车为迄今先秦考古中所仅见,是国家一级文物。对它的保护和修复,不仅是对该车的抢救和保护,也是运用现代科学技术,结合历史文献所进行的一次先秦鼓车的实验考古。在发掘、复原、复制的基础上,对其进行保护和修复是对中国古代车制研究的一个贡献,也为研究和展示中华文明提供了重要实物。     

基于虚拟样机技术的坦克步兵战车实战演习仿真

BMP-2是前苏联时期制造的步兵战车，该战车虽制造年代久远，但对以后世界步兵战车的发展起到引导作用。其主要特点是坦克配备一门机关炮和拱肩反坦克导弹。为了实现该步兵车实战演习过程，在 ADAMS 中建立该步兵车的虚拟样机模型，对模型的各部件添加约束和驱动，并进行运动仿真，以显示该型步兵战车的强大作战力。     

中国古代军事工程技术管理机构的演进

Based on the continual development of the military engineering and technology in different historical stages in ancient China, this article describes the evolving process of the corresponding management institutions and discusses its causes. The whole process is divided into several historical phases, including germinating, shaping, developing, systematizing and modernizing. The author thinks that the military engineering, the military technology and the management institutions depended on, mutually promoted and closely associated with each other and went ahead side by side in the long history. Through serious study of the history development of the management institutions, readers can understand its ensuring function for the military engineering and technology and acquire the consciousness and foresight which is necessary for building and reforming the similar institutions.     

战车用压电速率传感器

分析了压电速率传感器零位电压、零位电压漂移产生的原因，着重讨论实现漂移自动补偿的原理，并给出了实验结果