Investigation of fabrication of gas diffusion substrate for proton exchange membrane fuel cells

The gas diffusion substrate (GDS) is essential in the proton exchange membrane fuel cells. Its fabrication techniques affect the performance significantly and are worthy of investigation. In this study, a manufacturing process of the GDS is proposed to understand the formation process of GDS and promote its structure and performance more pertinently. Different states during the preparation process, raw carbon paper, pre-curing, curing, carbonation, and graphitization, are characterized and measured. Experimental and numerical methods are employed to determine the relationships between microstructure, transport, and mechanical performance variation with the fabricating processes. The results show that its porosity, average pore size, and effective diffusivity decrease first and increase after curing. These parameters after graphitization are lower than that of the carbon paper (CP). The electrical resistivity increases dramatically while pre-curing and decreases gradually after curing, carbonation, and graphitization, and it is much reduced after graphitization. Moreover, mechanical measurement results show that both the picks of tensile strength and flexural modulus occur after curing. Its tensile strength shows little change after graphitization compared to the initial paper's. In contrast, the flexural modulus is improved significantly.     

激光打孔技术在光伏背板玻璃上的应用

双玻光伏组件以其抗PID性强、防隐裂、防水汽透过、抗蜗牛纹、可靠性优异、轻量化等诸多优点,在晶硅太阳能组件市占比逐步提高。双玻光伏组件用背板玻璃一般需要预留出线孔,光伏背板玻璃的出线孔主要有两种打孔方式:金钢钻上下同步钻孔的模式和激光打孔。激光打孔以其易维护、可异形孔加工、效率高、生产成本低等优势得到各大玻璃厂的认可。通过分析在实际生产中激光打孔出现的打孔缺陷问题,提出了改善措施,有助于工厂的降本增效。     

Concentration dependence of physical properties of low temperature processed ZnO quantum dots thin films on polyethylene terephthalate as potential electron transport material for perovskite solar cell

Colloidal Zinc oxide quantum dots (ZnO QDs) prepared with varying concentrations through precipitation method were deposited on flexible ITO/PET substrates using spin-coating technique. Various characterization tools were utilized to investigate the morphological, structural, electrical and optical properties of the films. The crystallinity of the films was found to improve with increasing ZnO QD concentration (ZQ_C) as evident from the X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) studies. Crystallographic and optical parameters were evaluated and explained in depth. The average nanograin size and bandgap were increased and decreased respectively, from ～5 nm to ～8 nm and 3.29 eV–3.24 eV with an increase in ZQ_C from 10 mg/mL to 70 mg/mL. Columnar structure growth of the films is revealed by AFM results. The films showed decent optical transparency up to 81%. All the ZnO films exhibited n-type semiconducting property as indicated by the electrical measurements with carrier mobility and low resistivity of 12.21–26.63 cm²/Vs and 11.84 × 10^?3 to 13.16 × 10^?3 Ω cm respectively. Based on the experimental findings, ZnO QD nanostructure film grown at 50 mg/mL is envisaged to be a potential candidate for flexible perovskite photovoltaic application.     

Preparation of P(St-NMA) microsphere inks and their application in photonic crystal patterns with brilliant structural colors

Patterned photonic crystals with structural colors on textile substrates have attracted a special attention due to the great advantages in application, which currently become a research hot-spot. This study utilized an ink-jet printing technology to prepare high-quality photonic crystal patterns with structural colors on polyester substrates. The self-assembly temperature of poly(styrene-N-methylol acrylamide) (P(St-NMA)) microspheres set to construct photonic crystals were deeply optimized. Moreover, the structural colors of prepared photonic crystal patterns were characterized and evaluated. When the mass fraction of P(St-NMA) microspheres was 1.0 wt.%, the pH value ranged from 5 to 7, and the surface tension was in the range of 63.79 to 71.20 mN/m, inks could present the best print performance. At 60 °C, prepared P(St-NMA) microsphere inks were good for printing to obtain patterned photonic crystals with regular arrangement and beautiful structural colors. Specifically, photonic crystals with different colors could be constructed by regulating the diameter of microspheres in inks, and prepared structural colors exhibited distinct iridescent phenomenon. The present results could provide a theoretical basis for the industrial realization of patterned photonic crystals by ink-jet printing technology.     

纤维基表面增强拉曼基底的研究进展

为解决传统纤维表面拉曼增强(SERS)基底所存在的稳定性差、操作不便等问题。介绍了柔性SERS基底的优势,总结了目前各类纤维基SERS基底的研究进展及其在痕量检测领域的应用,简述了电磁增强和化学增强2种表面增强拉曼现象的基本原理。综述了纤维纸基SERS、织物基SERS、散纤维及纳米纤维膜SERS基底的制备方法及其应用,并着重介绍了织物基SERS材料的研究现状及其在在线检测应用方面的挑战与机遇。基于织物基SERS材料高度灵敏及灵活检测的特点,展望了其作为可穿戴传感器件用于即时检测和周身环境监测的前景,为拓展智能纺织品的应用领域开辟了新的思路。     

纸基底印刷无芯片RFID湿度传感器* .txt

摘要：提出了一种基于纸基底的喷墨印刷无芯片RFID湿度传感器，通过遗传算法与射频仿真软件HFSS相结合，对常规开口环谐振器结构进行分布式加载，得到目标频率为245 GHz的谐振特性良好的传感器模型；采用DMP3000型材料打印机，在不同纸基底上喷墨印刷银墨水制作传感器，以纸张本身的吸水性实现湿度传感；研究不同纸基底对湿度传感器感湿灵敏度和恢复度的影响。结果表明，柯达相纸传感器的灵敏度最高，高湿灵敏度可达到8 MHz%RH，双铜纸湿度传感器恢复度高且恢复时间短，仅为2 min；两种基底湿度传感器皆有较好的一致性、中长期稳定性，且湿敏特性在20℃～30℃范围内受温度影响较小。对纸基湿度传感器的感湿机理进行了分析，纸主要成分纤维素表面的羟基与吸附的水分子作用形成氢键，改变了基底的介电参数，传感器的湿敏特性与纸的成分和结构有关。 .txt     

辊式涂布法构建纸基牢固超疏水表面

采用辊式涂布的方法在纸基材料上构建超疏水表面，并对超疏水表面的牢固性、自清洁性和疏水性能进行评价。用γ-氨丙基三乙氧基硅烷和1H,1H,2H,2H-全氟辛基三乙氧基硅烷（POTS）对微米级和纳米级两种尺寸的TiO₂粒子进行疏水改性处理，然后将改性后的微/纳米TiO₂涂布在纸基材料表面。采用红外光谱（FTIR）对改性后的微/纳米TiO₂的化学组成进行了分析，采用扫描电镜（SEM）对涂布纸表面结构进行了表征，通过接触角、耐磨性和自洁净测试评价了涂层表面的超疏水性、牢固性和自清洁性。改性TiO₂的FTIR分析显示在1000～1500cm^-1之间出现多个C—F键的伸缩振动峰，表明POTS通过化学键与TiO₂表面发生了结合。涂布纸表面的SEM分析可以看出，纸基材料表面上均匀分布了微米和纳米尺寸的TiO₂颗粒，具备了类似荷叶表面微-纳结构的粗糙表面。涂层表面的水接触角为153°±1.5°，滚动角为3.5°±0.5°，水滴在涂层表面呈球形，极易滑落，涂层在水中浸泡7天后，接触角没有发生明显变化，表明纸张表面具备了优异的超疏水性能，且疏水稳定性较好。涂层表面经过10次循环磨损试验后，接触角仍能达到150°，滚动角为9°，表明机械摩擦没有对涂布纸表面的化学成分和粗糙结构造成明显的破坏，超疏水表面的牢固性较好。自洁净测试表明，涂布纸表面具有良好的自清洁和防污性能。该工艺过程操作简单，易于实现工业化生产，为在纸基表面构建综合性能优异的超疏水表面提供了一种新的便利途径。     

IC基板传输机器人末端执行器结构拓扑优化设计

在半导体封装基板检测的传输过程中,末端执行器对其快速稳定高效率的传输起着关键作用。在满足设计强度、刚度的条件下,以末端执行器轻量化为目标,建立了末端执行器的三维模型,利用有限元分析软件ANSYS对基板传输机器人末端执行器进行静力学和模态分析,得到末端执行器在最大载荷情况下的应力、应变特性和对应的振型,并对其进行拓扑优化设计,根据拓扑优化结果建立新的末端执行器结构,对新的结构进行强度校核,验证设计方案的有效性。研究结果表明,优化后末端执行器的前四阶固有频率都大于伺服电动机的回转频率(50Hz),质量减少了26.7%,较好地实现了轻量化的目标,同时为后续的相关产品研制提供了一种新的技术方案。