CAN总线在电力机车分布式直流110 V电源中的应用

分布式电源功率大,稳定性高.为了使各个分布式功能模块能够相互协调工作,模块间的通信显得尤为重要.主要介绍利用CAN总线实现分布式电源各个模块间的通信,利用TMS320F2812芯片,实现整个CAN通信网络的控制.     

探地雷达钢筋正演模拟及偏移成像研究

探地雷达（ground penetrating radar,GPR）在工程检测领域应用广泛,特别是应用于隧道衬砌结构检测。利用时域有限差分方法（finite difference time domain,FDTD）和完全匹配层（perfect match layer,PML）吸收边界条件,采用900 MHz天线,模拟了不同间距、不同深度、不同对应位置的单、双层钢筋混凝土结构,并运用频率-波速域（F-K）波动方程偏移技术分别进行了成像处理。研究表明： 1）有效探测范围内钢筋间距、埋深越大时,干扰信号越少,钢筋的反映越明显; 2）F-K偏移可较好地分辨出单层（上层）钢筋,斜对双层钢筋的分辨率比正对高。     

超低功耗电子温度计的设计

以MSP430F2274单片机作为系统的控制核心设计超低功耗电子温度计,选用总线式温度传感器DS18B20测量温度,显示部分采用LCD驱动专用芯片HT1621驱动4位半液晶LCD玻璃片.试验表明,系统达到了设计要求,并且整机静态功耗约为2.97 μW.     

某型蓄电池叉车状态监测器设计

设计了基于C8051F020的蓄电池叉车状态监测器,讨论了蓄电池组的电量测量方法和叉车载货量测量方法,分析了监测器的硬件组成,并给出了单片机的软件流程图。在叉车驾驶员培训中的应用,表明该监测器达到了既定目的。     

光纤隔离变换器在光电式电流互感器中的应用

在介绍Rogowski线圈光电式电流互感器基本原理的基础上,设计了一种基于电N／N率（V／F）,频率／电压（F／V）转换原理的光纤隔离变换器,实现了互感器高压端与低压端的电气隔离。论述了电路的结构、工作原理、硬件设计等,并通过实验进一步阐明光纤隔离变换器的工作原理。现场实验表明,该光线隔离变换器具有良好的线性度,传输精度高,工作稳定。     

一种新型航海电子六分仪测角系统研究

介绍了一种新型高精度航海电子六分仪的结构原理,设计了以单片机MSP430F123为核心的控制、显示系统.当六分仪刻度位置发生变化时,旋转编码器产生12位二进制数字信号,传送给单片机系统进行处理、显示.该系统已经在实际教学中应用,运行稳定.     

Examination of factors affecting freeway incident clearance times: a comparison of the generalized F model and several alternative nested models

Traffic incidents are a principal cause of congestion on urban freeways, reducing capacity and creating risks for both involved motorists and incident response personnel. As incident durations increase, the risk of secondary incidents or crashes also becomes problematic. In response to these issues, many road agencies in metropolitan areas have initiated incident management programs aimed at detecting, responding to, and clearing incidents to restore freeways to full capacity as quickly and safely as possible. This study examined those factors that impact the time required by the Michigan Department of Transportation Freeway Courtesy Patrol to clear incidents that occurred on the southeastern Michigan freeway network. These models were developed using traffic flow data, roadway geometry information, and an extensive incident inventory database. A series of parametric hazard duration models were developed, each assuming a different underlying probability distribution for the hazard function. Although each modeling framework provided results that were similar in terms of the direction of factor effects, there was significant variability in terms of the estimated magnitude of these impacts. The generalized F distribution was shown to provide the best fit to the incident clearance time data, and the use of poorer fitting distributions was shown to result in severe over‐estimation or under‐estimation of factor effects. Those factors that were found to impact incident clearance times included the time of day and month when the incident occurred, the geometric and traffic characteristics of the freeway segment, and the characteristics of each incident. Copyright © 2012 John Wiley & Sons, Ltd.     

嵌入式PLC高速脉冲输出的研究与实现

本文介绍了基于C8051F020单片机的嵌入式PLC的高速脉冲输出功能的开发。灵活运用C8051F020内部提供的可编程计数器阵列(PCA)模块实现了PLC高速脉冲输出功能。     

乌鞘岭隧道F7断层的黏弹性位移反演分析

工程材料受力变形的性态常与时间有关,这类现象一般称为材料变形的黏性效应,材料发生随时间而增长的变形时,如果始终处于弹性受力状态,则称发生的变形为黏弹性变形。结合乌鞘岭隧道穿越F7断层段所取得的量测资料,将计算区域内的岩石视为均质各向同性体,初始地应力假设成均匀分布,采用三单元模型,对有限元黏弹性问题进行优化反演分析,得出围岩区域内的水平侧压力系数和所使用模型中的弹性模量和黏滞系数。反演分析表明,该隧道发生较大变形的主要原因是较大应力场的存在、围岩的软弱和较强的蠕变性。结论可为挤压性断层中隧道的支护设计、施工组织提供可靠的依据。     

M701F燃机燃烧系统简介

介绍三菱生产的M701F型重型燃气轮机燃烧系统的主要结构特点以及燃烧系统设置的主要保护。