Carbon vacancies improved photocatalytic hydrogen generation of g-C3N4 photocatalyst via magnesium vapor etching

Vacancies engineering was widely reported as the promising strategy for the improvement of the photocatalytic performance of semiconductor photocatalysts. In current work, carbon vacancies are constructed successfully in graphitic carbon nitride (g-C₃N₄) photocatalyst via magnesium vapor etching. Experimental results show that the formed carbon vacancies in g-C₃N₄ photocatalyst can significantly improve the photocatalytic H₂ generation performance. XRD, FTIR, SEM/TEM, XPS and PL characterization data are employed to evidence the construction of carbon vacancies, which are revealed to be the reason for the enhancement of photocatalytic H₂ evolution. This work develops an alternative route to construct carbon vacancies in g-C₃N₄ materials and gives an insight into the influence of vacancies on the photocatalytic performance of photocatalysts.     

Prediction of stable high-pressure structures of tantalum nitride TaN2

Structure searches based on a combination of first-principles calculations and a particle swarm optimization technique unravel two new stable high-pressure structures (C2/m and Cmce) for TaN₂. The structural features, mechanical properties, formation enthalpies, electronic structure, and phase diagram of TaN₂ are fully investigated. Being mechanically and dynamically stable, the two phases could be made metastable experimentally at ambient conditions.     

高职模具专业的产学结合培养模式

在高职模具专业的快速发展中,构建产学结合培养模式已成为当务之急。高职院校应从培养应用性技能人才出发,进一步密切学校与行业企业合作、校内基地与校外基地有机结合、理论与实践相互融合,在实施专业教学体系的综合改革中,强化实践教学环节,提升专业实验室和师资队伍的建设水平,着力于培养适应行业企业需要的应用性技能人才。     

Structure and properties of rigid foams derived from quebracho tannin

The first highly porous organic rigid foams based on condensed tannin extracted from quebracho tree (Schinopsis sp.) are reported. Samples having different densities have been prepared and characterised. Their porous structure and physical properties have been compared with those of foams prepared in similar conditions but based on mimosa or pine tannins. We show that the properties of quebracho foams are comparable, and in some cases better, than those made from other tannins. Quebracho and mimosa present very similar behaviours, attributed to the fact that the corresponding flavonoid units have identical reactive A-rings. In contrast, pine foams behave differently, due to their different A-ring. The results indicate that quebracho is thus an excellent alternative to mimosa for producing thermally insulating tannin foams presenting good mechanical performances.     

Fatigue Behavior of HDPE Composite Reinforced with Silane Modified TiO2

The composite of high density polyethylene reinforced with silane-modified TiO2 particles (silane-TiO2/HDPE) is a potential bone substitute biomaterial. The structure, bioactivity, and mechanical properties of silane-TiO2/HDPE are analogous to those of natural bone, correspondingly. In order to investigate the effect of silane connection and saline solution on fatigue behaviors, flexural fatigue tests with this composite were carried out in both air and saline solution. Saline solution was found to have different effect on fatigue life. In saline solution, the fatigue life could be improved at stress levels lower than 30 MPa, while the fatigue life could be reduced at stress levels higher than 30 MPa. After analyzing the fracture morphologies, different failure mechanisms were proposed, and the important role of silane connection in the composite during the fatigue process was discussed. Silane connection cannot only support the loading stress but also hinder the failure process under loading effectively. For dry specimens, no interfacial failure between the filler and matrix was found. For wet specimens, it is inferred that the synergetic effect of saline solution and high concentrated stress at high stress level could easily destroy the silane connection, which accelerated the fracture process, whereas the synergetic effect of saline solution and silane connection at low stress level could promote the formation of more microcracks on sample surface, which hindered the final fracture.     

制药机械中螺杆的简易设计及制造

针对设备中出现的碎瓶现象,分析了分瓶螺杆螺旋线的设计缺陷,采用等速运动替代正弦加速度运动设计,在生产中取得了良好的经济效益.     

重型清障车吊臂的有限元应力分析

利用有限元分析技术,对重型清障车吊臂的应力进行分析计算,得出各结构部件在不同工况下的应力分布图.分析计算结果,找出结构不合理之处,提出改进意见,进而为产品的优化设计提供理论依据.     

滚珠螺母的机器视觉检测

提出了基于机器视觉检测技术的滚珠丝杠副螺母的非接触测量方法。将用A102FCCD数字摄像头采集的图像经过IEEE1394数字接口卡传输到计算机。对原始数字图像实施预处理、二值化、轮廓提取及细化等处理后,将图像信息转变成宏观图形信息。在尺寸测量时,借助于图像处理中提取的边界,使用自编程序测量和计算螺母的螺距、珠心径、球面度误差、圆柱度误差及滚道锥度,其测量误差分别为0.001、0.023、0.010、0.016及0.006 mm。分析了误差产生的原因,指出光学误差是影响测量精度的主要因素。测量结果满足产品的技术要求。理论分析及实验结果表明了该方法正确可行。     

光伏电站集成检测系统设计

采用电子电路对光伏电站环境参数进行检测,将采样得到的环境温度、组件温度和光辐照量转换成相应的电信号。利用单片机的实时控制和数据处理功能,完成系统对环境参数的检测,配置了485总线与上位机进行通信。充分考虑光辐照量测量的各种干扰,进行了温度校正和谱校正,确保测量的准确性,实现了基于光伏电池的低成本光伏电站环境参数检测系统。