基于AT89C51的智能抢答与表决计时器的设计与实现

设计一种基于AT89C51单片机实现的抢答、表决与计时器,分别设计优先编码电路、锁存器、译码电路并将参赛队的输入信号在显示器上输出;报警电路可通过控制电路和主持人开关启动;计时功能通过定时电路和译码电路将秒脉冲产生的信号实现。经过试验模拟仿真,表明本设计抢答器具有反映快、功能多、实用性强的特点。     

零件材料硬化对产品结构性能的影响研究

冲压是制造业中广泛采用的一种成型方法,冲压件可作为结构件的1个非常重要原因就是它能达到工程上的强度及刚度的要求。基于冲压件的2种不同成型方式,利用专业冲压软件 PAMS-TAMP-2 G进行了有限元分析模拟,讨论冲件成型过程中材料硬化问题对产品结构及性能的影响,为产品设计及开发提供了一定的理论基础指导。     

Pulse-reverse electrodeposition of Ni–Mo–S nanosheets for energy saving electrochemical hydrogen production assisted by urea oxidation

Electrochemical hydrogen production from water splitting is one of the effective methods for hydrogen production that has recently attracted particular attention. One of the limitations of the electrochemical water splitting method is the slow oxygen evolution reaction (OER), which leads to an increase in overpotential and a decrease in hydrogen production efficiency. Here, Ni–Mo–S ultra-thin nanosheets were synthesized using the pulse reverse electrochemical deposition technique, and then this electrode was used as an electrode material for accelerating hydrogen evolution reaction (HER) and urea oxidation reaction (UOR). Remarkably, the optimized electrode needs only 74 mV to attain the 10 mA cm⁻² current density in HER and require only 1.3 V vs RHE potential in the UOR process. Also, results showed that the replacement of the UOR with the OER process resulted in a significant improvement in the electrochemical production of hydrogen in which for delivering the current density of 10 mA cm⁻² in overall urea electrolysis, only 1.384 V is needed. In addition, outstanding catalytic stability was obtained, after 50 h electrolysis, the voltage variation was negligible. Such outstanding catalytic activity and stability was due to 3-D ultrathin nanosheets, the synergistic effect between elements, and the superhydrophilic/superaerophobic nature of fabricated electrode.     

基于HFC的远程自动抄表系统构架

在研究各种通信方式的基础上,提出了解决水表、电表、燃气表远程抄表的基于HFC技术的解决方案,解决了"抄表—送单—收费—催费"的全过程自动化,也可实现客户在手机上通过Web浏览及查询用水、电、气的情况。     

高速切削细长轴类零件的研究与探讨

对于细长轴类工件,由于其自身和加工工艺系统刚性比较差,切削力、振动和切削温度对于细长轴的机械加工精度和表面质量的影响较大,而采用高速切削技术能有效地降低各种因素的不利影响,提高细长轴类零件的加工质量和生产效率。     

聚苯乙烯制品熔接线区域的双折射行为分析

基于双折射实验原理,利用偏光显微镜,运用"楔形法",测定了聚苯乙烯注塑制品熔接线区域厚度面上双折射行为分布。结果表明:距离嵌件的不同位置处,由于流动行为的差异导致了完全不同的双折射行为,根据应力-光学定律,这种行为也体现了塑料制品的分子取向、残余应力的分布情形。     

Effects of mixed abrasive grits in slurries on free abrasive machining (FAM) processes

Effects of mixed abrasive grits in slurries on free abrasive machining (FAM) processes are studied using a single-sided lapping machine. Impacts of mixing abrasives on various parameters such as amount of material removed, material removal rate, surface roughness, particle size distribution and relative angular velocity are studied. The material removed is monitored as a function of time. The experimental results suggest that (i) mixing abrasive grits can increase the amount of material removed, (ii) smaller abrasives can directly or indirectly affect the material removal process, (iii) slurries undergo severe grain size transition during lapping, and (iv) the surface roughness did not change significantly under different loading. The results of this study may have profound implication on the FAM processes that practitioners use today because the mixed abrasive grits increase material removal rate and reduce the grain size transition, while rendering similar surface roughness.     

5A05铝合金焊接工艺参数的计算机控制优化

通过计算机控制5A05铝合金的焊接工艺参数,研究了焊接电流、焊接速度、脉冲宽度和离焦量对焊接质量的影响。结果表明,5A05铝合金合宜的焊接工艺为:焊接电流198 A、焊接速度120 mm/min、脉冲宽度2 ms,离焦量+8 mm,此时焊缝可以在保持良好的表面成形性的同时,达到较为理想的焊接质量。     

1235铝合金冷轧板表面黑丝缺陷分析

采用电解铝液直接铸轧生产厚度为7.0 mm,宽度为1 050 mm的1235铝合金铸轧板,经2道次冷轧成厚度为2.1 mm铝箔坯料。采用光学显微镜(OM)、扫描电子显微镜(SEM)及能谱仪(EDS)等对厚为2.1 mm冷轧板表面黑丝缺陷显微组织进行研究和分析,探讨黑丝缺陷形成的原因。结果表明,冷轧板表面黑丝缺陷局部存在不规则的凹坑,凹坑内存在粗大夹杂物及第二相颗粒,且退火冷轧板黑丝缺陷晶粒相对正常基体数量多且较小。能谱分析表明这些粗大夹杂物是富含Al和O元素组成的非金属氧化物Al_2O_3,第二相颗粒是由富含Fe、Al元素且含量较低的Si元素组成的金属间化合物Al Fe Si,因此造成冷轧板出现了黑丝缺陷。     

连续盘式热风干燥器干燥盘结构设计与传热分析

为使食品得到更好的干燥以及提高干燥生产效率,在分析盘式干燥器工作原理的基础上,对干燥盘零件进行了几何结构设计、应力及变形分析,给出所选制造材料厚度的计算公式;分析干燥盘在工作中与物料颗粒的传热过程,总结出传热系数公式。参考该文相关理论生产的盘式干燥器运行良好,干燥效果显著。