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排序方式: 共有4622条查询结果,搜索用时 15 毫秒
1.
《International Journal of Hydrogen Energy》2022,47(83):35423-35436
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. 相似文献
2.
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。 相似文献
3.
《Ceramics International》2022,48(21):31559-31569
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 (ZQC) 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 ZQC 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. 相似文献
4.
为了获得新型HiPIMS稳定放电及制备优质膜层时的最优外部磁场参数,研究外部磁场变化对电-磁场协同增强高功率脉冲磁控溅射((E-MF)HiPIMS)放电及沉积特性的调制过程。在其他工艺参数保持不变的情况下,研究了外部磁场(线圈电流)对HiPIMS钒(V)靶放电规律以及V膜微观结构和性能的影响。采用数字示波器监测HiPIMS放电行为,利用XRD、SEM、AFM、摩擦磨损试验机及电化学腐蚀法等表面分析方法,研究V膜相结构、表面形貌、截面形貌、耐摩擦磨损性能及耐腐蚀性能等沉积特性。结果表明:随线圈电流的增加,基体离子电流密度逐渐增加,当线圈电流为6 A时基体离子电流密度最高可达209.2 mA/cm~2。V膜的相结构仅为V(111)但其晶面衍射峰强度随线圈电流的增加而逐渐增加。V膜表面呈现出典型的圆凹坑状形貌特征,其表面粗糙度先减小后增大且最小仅为10 nm。当线圈电流(4 A)较低时V膜生长表现为致密细小的晶体生长结构,膜层沉积速率随着线圈电流的增加而增加。当线圈电流为4 A时,V膜样品的摩擦系数最小、耐磨性最优,同时V膜样品具有最好的耐蚀性。 相似文献
5.
文中以多层石墨烯膜为敏感膜片,分别制备了基于PDMS、SU-8、氧化锆的石墨烯膜F-P声压传感器,应用薄膜与基底之间吸附理论,分析了石墨烯膜与基底间吸附能相对于基底材料的杨氏模量成正向变化的趋势,并实验测试了所制备的声压传感器灵敏度。实验结果表明,制备的PDMS和SU-8基底具有较大的表面粗糙度,其虽降低了与石墨烯膜的吸附能,但也造成悬浮石墨烯膜的周边固支边界条件变差,且较软的基底材料易导致F-P腔体变形,从而造成灵敏度整体上未能提升。 相似文献
6.
表面增强拉曼光谱(SERS)是基于探针分子的指纹信息(分子振动、转动信息等),可应用于具有灵敏度和特异性分子结构研究的分析技术.SERS借助具有优异的等离子体性能的贵金属纳米材料作为基底,可对单组分或复杂多组分的痕量农药残留物进行分析检测.其中,柔性SERS基底具有孔隙率高、制备成本低、柔韧可折叠弯曲等特点,在复杂样品体系中提取、过滤、浓缩探针分子等应用中具有刚性SERS基底不可比拟的优势.柔性SERS基底主要是由基于生物基材料、聚合物和碳材料的3类材料来支撑和固定修饰表面提供光谱增强作用的贵金属纳米材料.重点综述了这3种类型的柔性SERS基底常用制备方法及应用,充分利用SERS的"指纹图谱"分析优势,介绍了柔性SERS基底应用于不同农药残留的最新研究进展.最后,对SERS技术发展和应用提出了亟待解决的问题. 相似文献
7.
为提升纺织基材上光子晶体结构色的耐久性,从印花色浆性能和基材润湿性2个角度切入,以具有自交联特性的聚(苯乙烯–N–羟甲基丙烯酰胺)(P(St-NMA))胶体微球为主要成分制备印花色浆,采用丝网印花法在具有非对称润湿特性的纺织基材上构筑光子晶体生色结构,并测试制备所得光子晶体在纺织基材上的稳固性。结果表明:当印花色浆中微球质量分数为80%、自交联促进剂盐酸质量分数为5%10%时,有助于得到结构色鲜艳且结构稳固的光子晶体;采用等离子体技术可实现纺织基材的非对称润湿特性,当处理时间为3 min时,可得到正、反面接触角为56°和110°的纺织基材,且在此基材正面构筑得到的光子晶体能够兼顾结构色效果和结构稳固性。 相似文献
8.
Dr. Sven Nerdinger Eugene Kuatsjah Dr. Timothy E. Hurst Inge Schlapp‐Hackl Prof. Dr. Volker Kahlenberg Prof. Dr. Klaus Wurst Prof. Dr. Lindsay D. Eltis Prof. Dr. Victor Snieckus 《Chembiochem : a European journal of chemical biology》2018,19(16):1771-1778
A series of alkylated 2,3‐dihydroxybiphenyls has been prepared on the gram scale by using an effective Directed ortho Metalation–Suzuki–Miyaura cross‐coupling strategy. These compounds have been used to investigate the substrate specificity of the meta‐cleavage dioxygenase BphC, a key enzyme in the microbial catabolism of biphenyl. Isolation and characterization of the meta‐cleavage products will allow further study of related processes, including the catabolism of lignin‐derived biphenyls. 相似文献
9.
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. 相似文献
10.