非线性负折射率材料表面TE电磁波的空间稳定特性分析

针对电磁波在正负非线性材料界面处的传播,研究了两种稳定状态下电磁波的物理特性。理论分析和数值计算表明,该界面处电磁波的传播存在着频率通带,且带宽仅与两种材料的固有属性有关。得出前向表面波和后向表面波均可以在这种非线性导波系统中传播,并且在一定条件下,随着频率的变化,前向表面波和后向表面波可以在两种材料中跃变。推论出两种稳定传播的电磁波场峰值位置随传播功率的变化也能实现在两种材料中跃变,并逐渐向界面靠近,而传播功率较大的稳定态电场峰值几乎靠着界面。     

CISPR15 A1:2006对灯具电磁骚扰测试新增的要求

本文介绍了灯具电磁骚扰测试标准CISPR15对灯具辐射电磁场骚扰的新要求.同时也介绍了相应的实验室的应对策略.     

基于LPC2132和DS18B20的单总线数字测温系统设计

本文介绍一种新型嵌入式数字测温系统,该系统采用美国DALLAS公司生产的单总线数字温度传感器DS18B20为核心测温元件,以ARM7(LPC2132)为微处理器,给出了该系统的电路硬件设计与软件实现方法,并针对它在智能家居控制系统应用中出现的与硬件和软件有关的问题给出了解决方法.该系统具有结构简单、测温准确等特点,可作为一种新型的数字测温系统.     

一种对用户公平的核心无状态队列管理算法

在对"流"公平的CSFQ(Core-Stateless Fair Queueing)算法基础上进行改进,将算法设计思想由对流速率的公平分配改为对表征用户需求的效用函数的公平分配,从而提出一种对用户公平的核心无状态队列管理算法(Core-Stateless User Fair Queueing,CSUFQ),该算法能近似实现边界及核心路由器上对用户需求的最大最小公平,仿真实验证明了其效果.     

Bandpass filter with an ultra-wide stopband designed on miniaturized coaxial resonators

Characteristics of a new miniaturized coaxial resonator are theoretically investigated. It is shown that the first resonant frequency of the resonator can be significantly lowered relative to the second one and the resonator dimensions can be considerably decreased as compared to those of a traditional dielectric-filled quarter-wavelength coaxial resonator. Based on the investigated resonator, a fourth-order bandpass filter has been designed and fabricated. The filter stopband at a level of no worse than ?90 dB extends to the frequency that exceeds the passband center frequency by a factor of 47. Calculated frequency responses are in good agreement with those measured on the fabricated filter prototypes.     

Model-Based Control of Active Tilting-Pad Bearings

A promising mechanical bearing candidate for an active operation is the tilting-pad bearing. The proposed active tilting-pad bearing has linear actuators that radially translate each pad/pivot pair. The use of feedback control in determining the actuator forces allows for the automatic, continuous adjustment of the pad position during the operation of the rotating machine. In this paper, we develop a nonlinear dynamic model of the active bearing system. The hydrodynamic force produced by the fluid film is modeled as a nonlinear, squeeze-film damper plus repellent spring. A model-based nonlinear controller is then designed to exponentially regulate the rotor position to the origin. A proof-of-concept experiment shows that the active strategy improves the bearing performance relative to its traditional passive operation. Further, the experiment demonstrates that the model-based nonlinear control regulates the rotor comparably to a linear proportional integral derivative (PID) control, but requires significantly less control energy.     

一款基于树莓派的便携式智能灭火器设计

设计了一款基于树莓派的便携式智能灭火器,该设计过程包括采用瓶体模块设计,存储模块设计,远程监测与报警模块设计.其中,瓶体外部采用ABS阻燃材质,内部采用一种用于气溶胶罐的铝合金铝合金;存储模块采用无压存储S型气溶胶的方式;远程监控系统中使用树莓派作为中央控制器,辅以各种传感器采集信息,然后通过外部方式远程传输数据,实现...     

SDCCH信道话务量评估及最佳配置

本比较详细地阐述了SDCCH信道话务量的计算方法及在GSM网络中的配置原则，以便使网络资源达到最佳配置，发挥最大的经济效益。在论述中提出了3种方法：(1)建立SDCCH信道话务模型的方法；(2)评估SDCCH信道话务量的计算方法；(3)选择SDCCH信道最佳配置的方法。这3种方法供大家参考。     

图像制导导弹落角约束的制导律设计

针对某些图像制导导弹限制终端攻击角的作战要求,提出一种落角约束最优导引律。该导引律形式简单,易于工程实现。仿真结果证明,能满足脱靶量小的要求,对于某些机动的目标,该制导律都能够以期望的终端攻击角度命中目标,对于目标的机动具有较好的鲁棒性。     

机场激光驱鸟器扫描系统设计及应用

介绍了机场激光驱鸟器扫描系统设计的基本内容,即系统原理、功能、特点、组成及各分系统设计;分析了系统的要求和使用条件,对直流电机选型进行计算及校核,验证了设计的正确性和可靠性。