Reducing,Radical Scavenging,and Chelation Properties of Fermented Soy Protein Meal Hydrolysate by Lactobacillus plantarum LP6

Fermented soybean protein meal hydrolysate (FSPMH) was fractionated by gel filtration on Sephadex G-15. The fractions obtained were subjected to various antioxidant assays, amino acid and molecular weight determinations. Among the seven fractions, the highest antioxidant activity was found in fraction F2, with significant differences (P < 0.01) 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, hydroxyl radicals (^.OH) scavenging and Cu²⁺ chelating activity. Fraction F2 exhibited scavenging of DPPH (59.43%), ^.OH (72.80%) and 44.47% Cu²⁺ chelating activity. All other fractions showed variable activities in different assays. Amino acid analyses of F2 fraction with the strongest antioxidant activity also had the highest percentage of related antioxidative amino acids content (Histidine 3.46, Serine 5.78, Valine 4.08 and Lysine 11.49 g/100 g protein) compared with other six fractions. The molecular weight distribution of F2 was found to vary from 170 to 1500 Da.     

The physicochemical characteristics and hydrophobicity of high amylose starch–glycerol films in the presence of three natural waxes

The film forming behaviour and hydrophobicity of high amylose (HA) starch in the presence of three different natural waxes (beeswax, candelilla wax and carnauba wax) were studied in the presence and absence of Tween-80. The HA starch:glycerol (G) ratio was maintained at 80:20 (on dry solid basis) and the concentration of wax was varied from 5% and 10% (w/w). The melted wax samples were homogenized with HAG dispersion with or without Tween-80 and the films were prepared by solution casting. The hydrophobicity and water-barrier properties in these films were determined by using contact angle (CA), water vapour permeability (K_w) tests, and water sorption isotherm at 0.529 RH and 20 °C. The K_w values of the HAG films decreased significantly (p < 0.05) with the addition of 5% concentration of these waxes. Then the addition of Tween-80 to the HAG + wax films increased the K_w values significantly (p < 0.05). The presence of these waxes in the presence and absence of Tween-80 resulted into different sorption isotherms and the water adsorptivity and moisture diffusion coefficient values were also affected. The presence of Tween-80 increased the CA in HAG + carnauba wax films while the CA was found to decrease in the case of other two waxes. The highest hydrophobicity was observed in HAG + carnauba wax + Tween-80 films in which the CA was >80.0° both at 5% and 10% (w/w) wax concentration. These higher CA values in HAG + carnauba wax + Tween-80 films were found to be related to the higher surface roughness in these films.     

Improved PEM fuel cell performance with hydrophobic catalyst layers

Flooding of catalyst layers is one of the major issues, which effects performance of low temperature proton exchange membrane fuel cells (PEMFC). Rendering catalyst layers hydrophobic one may improve the performance of PEMFC depending on Pt percentage in the catalyst and Polytetrafluoroethylene (PTFE) loading on the electrode. In this study, effect of hydrophobicity in catalyst layers on performance has been investigated by comparing performances of membrane electrode assemblies prepared with 48% Pt/C. Ultrasonic coating technique was used to manufacture highly efficient electrodes. Power density at 0.45 V increased by the addition of PTFE, from 0.95 to 1.01 W/cm² with H₂/O₂ feed; while it slightly increased from 0.52 W/cm² to 0.53 W/cm² with H₂/Air feed. Addition of PTFE to catalyst layers while keeping Pt loading constant, enhanced performance providing improved water management. Kinetic activity increased by decreasing Nafion loading from 0.37 mg/cm² to 0.25 mg/cm² while introducing PTFE (0.12 mg/cm²) to the electrode. Electrochemical impedance spectroscopy (EIS) results proved that charge transfer resistance decreased with hydrophobic catalyst layers for H₂/O₂ feed. This is attributed to enhanced water management due to PTFE presence.     

A scratch-resistant and hydrophobic broadband antireflective coating by sol-gel method

A double-layer broadband antireflective (AR) and scratch-resistant coating with hydrophobic surface is fabricated via sol-gel process using acid and base catalyzed silica as precursor solutions. The coating is composed of a dense and a porous silica films of which the refractive indices are high and low respectively, realizing a step-index gradient structure with glass as the substrate. The AR property of the coating is optimized to maximize the amplification yield of the laser disk amplifiers used in high power laser system. The average transmittance of BK7 glass coated in this way increased to more than 99.5% over the range of 500 to 850 nm. After NH₃-heat treatment at 200 °C, the scratch-resistance of the coating is improved in a large degree. Trimethylchlorosilane is employed to modify the coating surface to improve the optical stability by resisting moisture. These treatments can ensure that this broadband AR coating is durable for its real application.     

Zinc oxide nanowire enhanced multifunctional coatings for cotton fabrics

Zinc oxide (ZnO) nanowires have been grown on cotton fabric to impart self-cleaning, superhydrophobicity and ultraviolet (UV) blocking properties. ZnO nanowires were grown by the microwave assisted hydrothermal method and subsequently functionalized with steraic acid to obtain a water contact angle of 150°, showing their superhydrophobic nature which is found to be stable up to 4 washings. UV protection of the resulting cotton fabric was also examined and significant decrease in the transmission of UV range was observed. Self-cleaning activity of the ZnO nanowire coated cotton fabric was also studied and it showed considerable degradation of methylene blue under UV light irradiation. These results suggest that ZnO nanowires could form ideal multifunctional coatings for textiles.     

复合绝缘子运行状态在线检测技术研究

对复合绝缘子运行状态在线检测技术进行了分类介绍,并探讨了各技术方案的特点与应用概况。     

硅橡胶表面分离水珠的局部放电对表面特性的影响

通过对硅橡胶表面存在分离水珠时的局部放电的测量和数据处理，得到了水珠局部放电相位谱图；并采用傅立叶变换红外光谱分析仪(FTIR)分析了局部放电引起的硅橡胶表面结构的变化。水珠间的放电过程中产生的热量和臭氧使硅橡胶表面发生裂解、氧化、交联、水解和缩合等反应，在其表面生产亲水性的硅醇、破坏甲基的对称结构和增加含氧量，这些导致了憎水性能的下降。