基于八路无线抢答器的设计

本抢答器是根据实际需要而设计的,它有两个功能：（1）8路无线抢答,用于抢答,结果由第四个数码管显示。而且又为观众加了一稍大屏幕显示,便于观众及选手及时知道抢答结果。（2）能够在1-999秒内倒计时,一方面用于抢答倒计时,一方面用于辩论赛倒计时,时间由前三个数码管显示。另外,当抢答成功和倒计时时间到时,都有蜂呜器进行语音提示。     

室外倒计时系统的设计与实现

基于AT89C51单片机的室外倒计时系统的设计方法和原理,重点阐述了时钟和点阵式LED显示电路设计的关键技术．该倒计时系统由适时时钟芯片、中央处理单元、译码、驱动、显示、键盘等几部分电路构成．能够使显示屏显示当前日期距离设定日期的天数,同时实现对当前日期、时、分、秒等数字的显示功能．显示屏的字符清晰．系统工作稳定．     

对油膜滑动摩擦系数测量系统的研究

为了改变张力法中对静摩擦系数不易测量、滑轮对测量精度的影响和减少操作者的测量误差.该系统利用通电螺线管产生的均匀磁场,通电导体在磁场中受到的洛伦兹力与摩擦力相等做匀速运动的基本物理规律.通过光电测速技术,由AT89C52单片机来调节流入导体的电流强度,使被测物体达到匀速.同时计算出摩擦系数值,并且由字符液晶显示模块HD44780显示出来.该系统不但可以测量相对油膜滑动摩擦系数,而且可以测量油膜最大静摩擦系数,只要更换少量器件可以用于各种摩擦系数的测量.因此该系统有较大的实用价值.     

Effect of CO2 enrichment on the glucosinolate contents under different nitrogen levels in bolting stem of Chinese kale (Brassica alboglabra L.)

The effects of CO₂ enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassica alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO₂ concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO₂ concentration, N concentration, and CO₂×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO₂. However, at 20 mmol N/L, elevated CO₂ had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO₂ concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO₂ concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO₂ condition. Project (No. 2007CB109305) supported by the National Basic Research Program (973) of China     

全面理解与践行党的先进性建设

党的先进性建设既是目标,又是过程,在推进中必须正确把握其主观性与客观性、整体性与个体性、理论性与实践性、历史性与时代性、区域性与全球性的辩证关系。     

PLC网络中通信方式的研究

介绍了PLC及其网络中通信的RS-232C和RS-485标准,并探讨了PLC网络中常用的通信方式及今后技术发展的趋势。     

单片机与数字式温湿度传感器SHT11虚拟I2C总线设计

SHT11是瑞士Sensirion公司生产的具有I^2C总线接口的单片全校准数字式相对湿度和温度传感器。该传感器采用独特的CMOSens TM技术,具有数字式输出、免调试、免标定、免外围电路及全互换的特点,但对无I^2C总线接口的单片机却无法与之直接相连。可借助通用I／O口线来虚拟I^2C总线,即采用虚拟I^2C总线协议的编程方法实现与之接口。     

校园宾馆管理信息系统的设计与实现

基于C/S结构的校园宾馆管理信息系统,具有系统用户管理、客房信息管理查询、结算等功能.系统前台功能的实现采用可视的visual basic技术;网络数据库的访问则通过MS SQL Server2000技术来实现.     

基于80C51单片机控制的快速水分检测系统研究

水分是固体物料质量检测的重要指标.基于80C51单片机控制的快速水分检测系统由系统数据处理软件实现对数据的分析处理,能够快速地对水分进行测定.该检测系统体积小、工作可靠,功耗低,弥补了以往设备测量误差大及重复性程度高等问题.     

《C＋＋语言程序设计》课程教学模式的研究与实践

本文结合《C＋＋语言程序设计》课程的特点及在课程教学模式改革过程中的教学实践,以学校的＂一主一辅,三个结合＂教学模式为指导,从课程基本状况、教学模式框架、多元教学策略及教学效果评测等几个方面进行研究与探讨.