S7-300PLC构成PROFIBUS-DP网络的原理及应用

讨论用PLC构成PRORBUS-DP网络系统的方法.首先介绍DP网的概念和实现,然后结合一个实际的例子来着重阐明用PLC来实现DP网络的解决方法.     

Road traffic conditions in Kenya: Exploring the policies and traffic cultures from unstructured user-generated data using NLP

Road traffic accidents (RTA) are a prevalent cause of fatality with African countries having the highest fatality index (25–34 per quota). The World Health Organization estimates Kenya's fatality rate due to RTA at 28 per quota. From literature, the country's fatality and injuries have increased by 26% and 46.5%, respectively, since the year 2015. The country is faced with incomplete RTA data capturing, hindering effective planning and policy adjustments to curb the menace. In this paper, we scrapped user-generated data (Twitter) and national transport and safety authority's (NTSA) reports to shed light on traffic safety, practices, and cultures in the country. To this end, we gathered 1,000,000 tweets and 8000 speeding entries between 2015 and 2021 and performed natural language processing (NLP) and quantitative study of the data. We applied NLP and n-gram search of keywords to categorize data into 8 topics: traffic, public service vehicle (PSVs), policing, accident, infrastructure, recklessness, robbery, and corruption. From the data, policing, which touches on all police and law-enforcement-related activity was found to be highly correlated with PSVs, recklessness, accidents, traffic congestion, robbery, infrastructure, and corruption with indices of r(76) = 0.92, 0. 91, 0.87, 0.82, 0.81, 0.76, and 0.70, respectively with p < 0.001. The topic modeling confirmed the identified topics to be the latent discussion issues affecting the public. From the study, PSVs, policing and traffic flow were isolated as key issues that ought to be addressed immediately. The research recommended the integration of driver monitoring systems to strengthen policing. The research, which utilized unstructured data, points to the utility of data mining which would greatly benefit traffic research, particularly African-based studies, that suffer from data inadequacy.     

Kinetic spectrophotometric method for determination of amlodipine besylate in its pharmaceutical tablets

A simple and sensitive kinetic spectrophotometric method has been developed and validated for determination of amlodipine besylate (AML). The method was based on the condensation reaction of AML with 7...     

SS7B与SS7C型电力机车的动力学性能试验研究

通过对在同一条线路上，结构基本相同但轴重不同，悬挂参数也进行了优化的两台ＳＳ７型电力机车进行的动力学性能试验，研究了轴重和悬持参数对机车动力学性能的影响，得到了有价值的结论，为机车的设计提供了重要的参考资料。     

基于嵌入式控制器的温度控制系统设计

为了较理想地解决被加热物件温度的测量与控制问题,运用最新嵌入式控制器ARM7TDMI处理器设计了一个炉温控制系统,介绍了该系统的硬件电路设计和软件设计.实践证明,运用ARM控制器系统的稳态精度达到±1℃以内,完全满足设计的要求.     

一种声呐仿真系统中的高速USB接口设计

通用串行总线是目前最常用的一种计算机总线.文中提出了一种高速USB接口芯片(EZUSB-FX2)实现数据通信的方法,该方法基于CY7C68013芯片的特点,利用其丰富的开发指令和灵活的程序设计来实现.介绍了接口硬件结构和软件设计,并给出了具体的设计方法和步骤.实验表明,该方法具有结构简单、传输率高的特点,适合于工程应用.     

朔黄线提高ZYJ7外锁闭道岔运用质量初探

介绍朔黄线严把"道岔初装关、工电整治关、维修技巧关",提高ZYJ7外锁闭道岔运用质量的做法,希望对类似工程提供借鉴。     

MAN B&W 6S42MC7主机滑油压力偏高的原因分析

根据32000DWT散货船主机MAN B&W 6S42MC7出现滑油压力偏高的现象,并通过理论计算进行论证,结果表明,理论计算与现场测量结果基本吻合,同时采取了增加流量调节阀的改进措施。     

重汽HOWO和A7空调系统原理分析及故障检测

以中国重汽主要车型——HOWO和A7为例,介绍车载空调系统的基本组成、线路连接,详细阐述空调控制原理和HOWO、A7空调控制的异同点,最后对空调系统的故障检测进行详细的说明。     

OPC服务器技术在港口机械数据监控系统中的应用

文章分析了当前港口机械监控系统组建遇到的问题,提出了解决问题的方法,并举例说明了如何利用OPC服务器实现监控系统的组建。