太阳能热水器的智能控制

以AT89S52单片机作为系统的控制核心,采用DS1302实时时钟,通过数字滤波提高系统各项指标和可靠性。应用单片机技术和模糊控制理论对太阳能集热器与储水水箱的热交换、电辅助加热进行分析。实现水位指示、自动给水、温度显示、定时给水、无给水自动停电报警等功能,利用LED显示器显示太阳能热水器的运行状况,使用方便。     

一种数字电压表的设计

本文介绍了一种数字电压表的设计方案,该方案以AT89S52单片机主控器为核心,与LCD显示电路、A／D转换电路等组成数字电压表控制系统。将电压模拟量通过芯片TLC549转化为数字量,AT89S52单片机将其处理后驱动液晶显示器LCD1602显示电压读数。     

基于单片机的数控直流电流源设计与仿真

本文是采用AT89S52控制的数控恒流电流源进行研究设计的,然后使用Proteus进行仿真。设计使用AT89S52单片机作为核心芯片,由键盘和显示模块,电压、电流转换装置等组成的数控直流电源。运用Proteus软件仿真,验证了设计方法的正确性,节省了开发成本。     

电动钻机故障监控智能从站的开发

以AT89S52单片机和PROFIBUS专用芯片VPC3+C为核心,设计对直流电动钻机中的西门子PLC系统具有故障监控及显示功能的智能从站,从而很好的解决跳断性等故障难以查处的难题。     

一种简易可靠的电缆充气机压力检测系统

本文介绍的电缆充气机压力检测系统以AT89S52单片机为核心,利用压力传感器26PCDFA6G将压力转换为电信号,电信号经过放大电路后通过12位的模/数转换芯片TLC2543以实现A/D转换,且使检测精度有很好的保证,其输出数据读入AT89S52单片机作为程序执行依据,为使本系统实用性更强,设计了压力值LED显示与报警电路。     

基于单片机AT89S52的晶闸管触发电路设计

该文阐述了基于单片机AT89S52构成的三相半波可控整流电路晶闸管触发电路的设计，介绍了AT89S52单片机控制的触发装置的硬件与软件设计，并且成功地改造了KGT-1型晶闸管调速装置。     

基于AT89C51的数字电子时钟系统设计

本文主设计的是以AT89C51为核心的数字电子时钟,使其具备在数码管上动态显示小时、分钟、秒以及温度数值的功能,时钟显示周期为24小时制,并且可以通过按键进行时间校对调节以及过程控制,另外同时还具备整点报时功能以及运用DS18820温度传感器进行温度的采集显示功能。     

基于单片机实现多功能数字钟的系统设计

多功能数字钟的系统采用AT89S52单片机作为控制系统的核心,模型采用单片机作为主控制器,利用DS1302时钟芯片计算当前的秒、分、时、日、月、年。通过1602液晶屏友好的人机界面将结果完美的呈现给用户。为可以灵活的设置时间,增加4x4键盘模块通过键盘扫描可以对当前的时间随意设置,除此又增加秒表、闹钟、生日提醒和整点提醒的功能。为具有更高的实用价值,通过DS18B20来显示当前温度,并伴有温度报警功能。利用键盘模块对预设的温度报警上下限进行设置。由于该系统具有时间显示、闹钟、秒表等完整功能,有很高的利用价值。     

基于单片机的室内环境监测系统设计

以AT89S52单片机为控制核心设计分析了可用于对室内环境进行监测和报警的控制系统。该系统使用传感器技术等单片机控制技术实现了对家居环境的温湿度、煤气浓度与甲醛浓度的采集、显示与状态报警等功能。文章首先对系统的硬件结构和各模块功能进行了分析,然后从软件设计的角度对各功能的实现进行了阐述,最后对其应用优势进行了总结。     

一种简单便携式单相电能表的硬件设计

该智能单相电表主要由两大部分组成,一是基于BL6503的电功率采集处理部分,二是基于AT89S52的显示输出部分。     

数字钟集成电路应用及其功能扩展

本文介绍了由大规模时钟集成电路 LM85 60芯片组成的数字钟电路及其多种扩展电路 ;叙述了其在高校电子电路课程设计中应用的意义     

EDA技术及其应用

阐述了EDA的工程设计流程,介绍了基于EDA技术的闹钟系统设计的内部原理结构图及硬件验证结果,总结了利用EDA技术进行电子设计的特点.     

芯片级原子钟的研究进展

芯片级原子钟是一种小型、低功耗、高精度的时间频率设备,与微惯性测量组合和卫星导航技术相结合,形成微型导航定位授时单元,可广泛应用于国民经济、军事领域和国家安全等方面.本文介绍了国内外芯片级原子钟的研究进展及现状,阐述了芯片级原子钟研制的难点及需要突破的关键技术,包括微型原子气室制备技术、微机电系统集成技术和芯片级光学频...     

Comparative analysis of driver’s brake perception-reaction time at signalized intersections with and without countdown timer using parametric duration models

Countdown timers display the time left on the current signal, which makes drivers be more ready to react to the phase change. However, previous related studies have rarely explored the effects of countdown timer on driver’s brake perception-reaction time (BPRT) to yellow light. The goal of this study was therefore to characterize and model driver’s BPRT to yellow signal at signalized intersections with and without countdown timer. BPRT data for “first-to-stop” vehicles after yellow onset within the transitional zone were collected through on-site observation at six signalized intersections in Harbin, China. Statistical analysis showed that the observed 15th, 50th, and 85th percentile BPRTs without countdown timer were 0.52, 0.84, and 1.26 s, respectively. The observed 15th, 50th, and 85th percentile BPRTs with countdown timer were 0.32, 1.20, and 2.52 s, respectively. Log-logistic distribution appeared to best fit the BPRT without countdown timer, while Weibull distribution seemed to best fit the BPRT with countdown timer. After that, a Log-logistic accelerated failure time (AFT) duration model was developed to model driver’s BPRT without countdown timer, whereas a Weibull AFT duration model was established to model driver’s BPRT with countdown timer. Three significant factors affecting the BPRT identified in both AFT models included yellow-onset distance from the stop line, yellow-onset approach speed, and deceleration rate. No matter whether the presence of countdown timer or not, BPRT increased as yellow-onset distance to the stop line or deceleration rate increased, but decreased as yellow-onset speed increased. The impairment of driver’s BPRT due to countdown timer appeared to increase with yellow-onset distance to the stop line or deceleration rate, but decrease with yellow-onset speed. An increase in driver’s BPRT because of countdown timer may induce risky driving behaviors (i.e., stop abruptly, or even violate traffic signal), revealing a weakness of countdown timer in traffic safety aspect.     

雷电电磁脉冲自动监测系统的研究

研究了以雷电检测电路、主控MCU．时钟巷片,键盘,液晶显示、串行通讯接口、看门狗及电源监控电路等部分组成的雷电自动监测系统,并对其单片机软件设计,给出了程序流程图。     

某奥运体育场馆排烟系统和补风系统性能化设计

采用NFPA92B所提供的烟气控制计算公式对某奥运体育场馆的排烟量进行计算,并利用CFD数值模拟软件对排烟系统及补风系统进行优化设计,研究在该体育场馆内机械排烟,机械补风,自然补风三者之间的内在联系以及机械补风量对某馆排烟系统的影响。对该奥运体育场馆排烟系统以及补风系统的优化设计提供了理论依据。     

Production and test of a readout chip for the ALICE SDD experiment

The paper summarizes the design, the fabrication and test of a chip for the silicon drift detector experiment, part of the A Large Ion Collider Experiment (ALICE) at CERN. The chip performs data reduction via bidimensional compression and packing for the readout chain of the experiment. The chip interfaces with front-end electronics and with the counting room. It is synchronized with a 40 MHz system master clock and configured via a serial signal. The work presents the tests that were performed to characterize the chip and it exploits the final yield of 89% over 700 fabricated chips. The whole tests were performed in laboratory and the chip was also tested in a test beam at CERN in November 2004.     

Preliminary results of the trapped atom clock on a chip

We present an atomic clock based on the interrogation of magnetically trapped ⁸⁷Rb atoms. Two photons, in the microwave and radiofrequency domain, excite the clock transition. At a magnetic field of 3.23 G the clock transition from |F = 1, m_F = -1? to |F = 2, m_F = 1? is 1st-order insensitive to magnetic field variations. Ramsey interrogation times longer than 2 s can be achieved, leading to a projected clock stability in the low 10^-13 at 1 s for a cloud of 10⁵ atoms. We use an atom chip to cool and trap the atoms. A coplanar waveguide is integrated to the chip to carry the Ramsey interrogation signal, making the physics package as small as (5 cm)³. We describe the experimental setup and show preliminary Ramsey fringes of line width 1.25 Hz.     

北京2022年冬奥会文化符号设计与传播价值研究

目的 分析基于符号的传播特性、文化符号的内涵和视觉性,对北京2022年冬奥会文化符号的设计进行分析,旨在为未来冬奥会文化符号的设计提供有益借鉴。方法 以符号学和文化符号为理论基础,从符号的符形与符义、能指与所指等角度,对北京冬奥会文化符号设计理念与造型设计进行分析,引申出北京冬奥会文化符号的意指内涵,从而得出北京冬奥会文化符号的设计特征。此外,北京2022年冬奥会文化符号具有很大的传播价值,可以传递本国的文化价值、彰显深厚的审美价值、凝聚奥林匹克的社会价值。结论 冬奥会文化符号是向世界传递冰雪文化和民族文化的重要媒介,是世界文明进行交流与沟通的桥梁,其设计理念要传承民族传统文化的内涵,设计形式要注重创新和突破,从而实现与世界文化的交融。     

System requirements of a stationary-head multi-track recorder

We report on the design considerations of stationary-head multi-track magnetic recorders. We focus on the particular reasons for adopting the rate 8/10, DC-free recording code, the full-response detection method, and the clock recovery circuitry. Implementation issues of the channel chip, particularly related to cost and power consumption, are addressed. A new multi-track phase-lock loop (PLL) has been developed, in order to improve the recorder's robustness against time-base variations