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.     

One-step to prepare high-performance gas diffusion layer (GDL) with three different functional layers for proton exchange membrane fuel cells (PEMFCs)

Gas diffusion layer (GDL) is one of the most important components of fuel cells. In order to improve the fuel cell performance, GDL has developed from single layer to dual layers, and then to multiple layers. However, dual or multi layers in GDL are usually prepared by layer-by-layer methods, which cost too much time, energy, and resources. In this work, we successfully developed a facile one-step method to prepare a GDL with three functional layers by utilizing the different sedimentation rates and filtration rates of short carbon fiber (CF) and carbon nanotube (CNT). The treatment temperature for this GDL is much lower than that of traditional method. The thickness of the GDL can be effectively controlled from as thin as 50 μm to more than 200 μm by simply adjusting the content of CF. The GDL with high flexibility is suitable to develop high performance flexible electronics. The fuel cell with the GDL has the maximum power density 1021 mW cm^?2, which shows 19% improvement comparing to the conventional one. Therefore, this work breaks the traditional concept that GDL for fuel cells only can be prepared by very complex and high-cost procedure.     

柠檬草精油成分分析、抑菌性及对巨峰葡萄保鲜研究

采用中国西南地区的柠檬草,以水蒸气蒸馏法提取得到的柠檬草精油(lemongrass essential oil,LEO),通过气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS)分析柠檬草精油的成分和相对含量;通过测定抑菌圈直径和最低抑菌浓度研究对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌的抑菌效果;研究不同浓度的柠檬草精油对新鲜采摘的巨峰葡萄产品品质和生理的影响,确定其保鲜作用。结果表明:当料液比达到1∶15(g/mL)时,出油量与得率达到最大,平均得率为0.91%。利用GC-MS分析柠檬草精油成分,其中有21种组分,主要成分为柠檬醛,占比为70.11%。柠檬草精油对3种供试菌均有较好抑制作用,对枯草芽孢杆菌、金黄色葡萄球菌和大肠杆菌抑菌圈大小分别为23.8、22.5 mm以及11.2 mm。其中对金黄色葡萄球菌和枯草芽孢杆菌的抑制效果较好,对金黄色葡萄球菌和枯草芽孢杆菌的最低抑菌浓度为0.1μL/mL,大肠杆菌的最低抑菌浓度为0.2μL/mL;与对照组相比,柠檬草精油处理能有效缓解可滴定酸、可溶性固形物含量和硬度的降低,减少烂果率和失重率,其中0.50%柠檬草精油处理组的保鲜效果明显好于其他处理组。由此可见,柠檬草精油具有抑菌和水果保鲜的作用。     

生活用纸湿强剂PAE残留的风险评估

介绍了生活用纸中湿强剂聚酰胺环氧氯丙烷树脂（PAE）的残留状况及对人类健康的风险隐患；结合欧盟法规规定和风险评估模型，计算了生活用纸中残留PAE经皮肤摄入的风险指数，并进行了PAE残留风险评估。结果表明，PAE中的有机氯代物在纸巾纸等生活用纸中残留的概率较大，长期接触这些有害物质将对使用者的身体健康产生潜在的风险隐患。     

着-聚赖氨酸/淀粉抑菌膜的制备及性能检测

对以淀粉为成膜基质,海藻酸钠和甘油为增塑剂,ε-聚赖氨酸为抑菌剂的淀粉基抑菌膜进行研究,并对其抑菌性和膜性能进行检测。结果表明,ε-聚赖氨酸对大肠杆菌、枯草芽孢杆菌和酵母菌的最低抑菌浓度分别为1、2、2μg/mL,而将ε-聚赖氨酸添加到淀粉膜后,最低抑菌浓度都提高到64 mg/g,对淀粉膜和抑菌膜的力学性能、红外光谱检测、透气性和透油性及膜液的流变性、接触角等比较,差异较小。     

超支化聚合物对羊毛织物的改性研究

为了改善羊毛织物的防毡缩性能,利用三羟甲基磷(THP)交联作用,将端氨基超支化聚合物(HBP-NH2)共价结合到羊毛纤维上,并测试整理后织物防毡缩、抗菌和染色性能及断裂强力变化。结果表明:单独使用超支化聚合物处理,羊毛织物的毡缩率由20.69%下降到17.31%,未达到羊毛织物防毡缩的目的;而经三羟甲基磷/超支化聚合物处理后,羊毛织物的毡缩率下降到7.43%,达到机可洗标准;且抑菌率达92.37%,低温条件下羊毛织物的染色性能也得到明显改善。     

制浆造纸行业水污染全过程控制技术理论与实践

制浆造纸行业是我国水污染防治的重点,减排任务艰巨。在环境倒逼下,造纸行业加快淘汰落后产能和完善末端治理技术,污染控制取得了初步成效。但随着国家和地方环境治理由浓度控制走向总量控制、质量控制,原有技术的局限性难以满足解决水污染的更高要求,必须创新污染防治方法。本文介绍了制浆造纸行业水污染全过程控制的基本理论和内涵,并结合化学法制浆、化学机械法制浆、废纸制浆与造纸过程水污染防治工程实践,提出了解决制浆造纸行业水污染的对策,为推动行业绿色转型升级和高质量发展提供了支撑。     

国内外纸质文献加固技术研究

纸张脆化问题既缩短了纸质文献的保存寿命,又限制了纸质文献的使用、研究与传承,对脆化纸质文献进行加固处理迫在眉睫。现有纸质文献加固技术使用的材料可以分为天然材料、合成材料以及复合材料三大类。本文从这三方面对纸质文献加固技术的研究进展进行了介绍,并综合考虑我国文献保护的实际情况,提出了开展纸质文献加固工作应遵循的原则和未来的研究方向,旨在为脆化纸质文献加固处理提供借鉴。     

用无机纳米粒子制备耐久性抗菌棉织物的研究进展

为有效地解决无机纳米粒子制备的抗菌棉织物耐久性能不佳的问题,提高无机纳米粒子的整理技术,对黏结剂结合棉织物表面无机纳米粒子耐久抗菌性能的最新研究进展进行综述,介绍了抗菌耐久性的评价方法、黏结剂固化无机纳米粒子在棉织物表面的后整理方法等,并分析了耐久性,对影响耐久性的因素以及抗菌效率、抗菌效率下降趋势和洗涤过程中无机纳米粒子的损失进行了阐述与分析。指出:氨基和巯基基团可与无机纳米粒子形成配位键,有效地将无机纳米粒子固定在棉织物表面上;微波辐射和超声波可应用于增强无机纳米粒子在棉织物表面的黏附力。     

化香果提取物体外抑菌活性研究

研究了化香果提取物对水产常见9种致病菌嗜水气单胞菌（Aeromonas hydrophila）、温和气单胞菌（Aeromonas sobria）、豚鼠气单胞菌（Aeromonas caviae）、维氏气单胞菌（Aeromonas veronii）、迟钝爱德华菌（Edwardsiella tarda）、副溶血弧菌（Vibrio parahaemolyticus）、鼠疫耶尔森氏菌（Yersinia pestis）、大肠杆菌（Escherichia coli）和金黄色葡萄球菌（Staphylococcus aureus）的抑菌活性。研究结果表明：化香果提取物对9种细菌均具有抑制作用，最小抑菌浓度为4.50 g/L。对每种细菌而言，抑菌效果随化香果提取物质量浓度的增加而增强，其中对大肠杆菌的抑制能力最强，IC₅₀值为0.035 g/L；金黄色葡萄球菌次之，IC₅₀值为0.053 g/L。对雌雄小鼠急性经口毒性试验结果表明化香果提取物对小鼠的急性经口半数致死量（LD₅₀值）分别为5 010和7 940 mg/kg体质量，表明化香果提取物属于实际无毒级。