基于纳米银聚集的共振散射光谱法测定痕量多巴胺

在弱酸性缓冲溶液中,质子化的多巴胺与表面包裹着柠檬酸根负离子的纳米银相结合,引起纳米银的聚集,导致体系在442 nm处共振散射强度增强,其强度增加值与多巴胺浓度呈线性关系,据此提出了一种利用纳米银的聚集效应采用共振散射技术测定痕量多巴胺的新方法。在选定最佳实验条件下,多巴胺的线性范围为1.0×10~(-7)~2.5×10~(-5)mol/L,线性回归方程为ΔI=2.808×10~7c+8.15,相关系数为0.999 2,检出限为2.78×10~(-8)mol/L。该方法操作简便,应用于注射液、人血清和尿液中多巴胺含量的检测,其加标回收率为96.4%~103.9%,相对标准偏差为0.31%~1.28%。     

铝氧化银电池的热设计

铝银电池是为鱼雷推进而开发的一次动力电池,需要工作在稳定的温度区间内。分析了鱼雷的航速和电解液温度对电池的产热功率和散热功率的影响。结果表明,当完成电池壳体设计时,鱼雷的航速和电解液温度范围也随之确定。通过进一步分析认为可通过使用温控阀、将壳体进行功能分区等方法增加鱼雷的航速范围。     

铝球化学镀银工艺的研究

利用聚多巴胺对铝球表面进行预处理,再通过化学镀方法在聚多巴胺改性的基体表面制备金属银层。采用X光电子能谱仪分析聚多巴胺改性基体表面的元素组成,并分别采用X射线衍射仪和扫描电子显微镜表征镀银铝球的晶相结构与表面形貌。结果表明:当硝酸银的质量浓度为10g/L时,在铝球表面可形成直径约为20nm的单质银,镀银铝球的导电性优良,电导率达10 000S/cm。     

Sodium alginate mediated route for the synthesis of monodisperse silver nanoparticles using glucose as reducing agents海藻酸钠为保护剂葡萄糖为还原剂合成单分散银纳米粒子

报道了一种在水溶液中的简单绿色法制备纳米银溶胶。硝酸银,海藻酸钠素,葡萄糖分别做为银源,保护剂和还原剂。纳米溶胶的颜色从无色变到黄色,表明生成了纳米银粒子。利用透射型电子显微镜（TEM）,紫外可见光谱（UV-vis）和X-射线衍射（XRD）对样品进行了分析。TEM图像表明,所得到的银纳米颗粒的为粒径较小,分散性较好的球状粒子,分布范围较窄,从3 nm 到12 nm。XRD结果表明所得到的纳米金属粒子为单晶的纳米银颗粒。通过UV光谱对反应时间、反应温度、银离子浓度及还原剂的浓度对粒径的影响进行了研究。由于该方法具有无污染、简单、廉价等优点,因此该方法可以做为一种较好的制备纳米银粒子的方法。该方法可以扩展到其它贵金属的技术应用,例如药用,工业应用等。     

Gasar工艺下藕状多孔银的气孔结构研究

金属-气体共晶定向凝固（Gasar)是制备藕状多孔金属的新工艺,利用自行研制的Gasar装置,成功地制备了不同纯氧分压下的藕状多孔银试样,研究了氧气分压对藕状多孔银气孔形貌（气孔率、气孔尺寸和分布、气泡形核）的影响。结果表明：氧气分压对气孔形貌影响十分显著。随着氧气压力的增加,气孔率增大而平均气孔直径减小。     

Novel Redox-Dependent Esterase Activity (EC 3.1.1.2) for DJ-1: Implications for Parkinson’s Disease

Mutations the in human DJ-1 (hDJ-1) gene are associated with early-onset autosomal recessive forms of Parkinson’s disease (PD). hDJ-1/parkinsonism associated deglycase (PARK7) is a cytoprotective multi-functional protein that contains a conserved cysteine-protease domain. Given that cysteine-proteases can act on both amide and ester substrates, we surmised that hDJ-1 possessed cysteine-mediated esterase activity. To test this hypothesis, hDJ-1 was overexpressed, purified and tested for activity towards 4-nitrophenyl acetate (pNPA) as µmol of pNPA hydrolyzed/min/mg·protein (U/mg protein). hDJ-1 showed maximum reaction velocity esterase activity (V_max = 235.10 ± 12.00 U/mg protein), with a sigmoidal fit (S_0.5 = 0.55 ± 0.040 mM) and apparent positive cooperativity (Hill coefficient of 2.05 ± 0.28). A PD-associated mutant of DJ-1 (M26I) lacked activity. Unlike its protease activity which is inactivated by reactive oxygen species (ROS), esterase activity of hDJ-1 is enhanced upon exposure to low concentrations of hydrogen peroxide (<10 µM) and plateaus at elevated concentrations (>100 µM) suggesting that its activity is resistant to oxidative stress. Esterase activity of DJ-1 requires oxidation of catalytic cysteines, as chemically protecting cysteines blocked its activity whereas an oxido-mimetic mutant of DJ-1 (C106D) exhibited robust esterase activity. Molecular docking studies suggest that C106 and L126 within its catalytic site interact with esterase substrates. Overall, our data show that hDJ-1 contains intrinsic redox-sensitive esterase activity that is abolished in a PD-associated mutant form of the hDJ-1 protein.     

Applied Voltage and Near‐Infrared Light Enable Healing of Superhydrophobicity Loss Caused by Severe Scratches in Conductive Superhydrophobic Films

The fabrication of self‐healing/healable superhydrophobic films that can conveniently and repeatedly restore the loss of superhydrophobicity caused by severe mechanical damage, such as deep and wide surface scratches, remains challenging. In the present work, conductive superhydrophobic films that are healable by means of an applied voltage or near infrared (NIR) light irradiation are fabricated by depositing a layer of Ag nanoparticles and Ag nanowires (AgNPs‐AgNWs) on a thermally healable polycaprolactone (PCL)/poly(vinyl alcohol) (PVA) composite film, followed by the deposition of 1H,1H,2H,2H‐perfluorodecanethiol. The AgNPs‐AgNWs layer not only provides micro‐ and nanoscaled hierarchical structures in support of superhydrophobicity but also serves as an electrothermal or photothermal heater to enable healing of the underlying PCL/PVA film under the assistance of a low applied voltage or low‐power NIR light irradiation. Because of the strong adhesion between the PCL/PVA film and the AgNPs‐AgNWs layer, the healability of the PCL/PVA film is successfully conveyed to the conductive superhydrophobic layer, which can rapidly and repeatedly restore the loss of superhydrophobicity caused by cuts several hundreds of micrometers wide. The combined electrothermal and superhydrophobic properties endow the healable conductive superhydrophobic films with improved durability and usefulness as self‐cleaning, antiicing, and snow‐removing surfaces.     

全泥氰化工艺尾水综合回收新工艺

针对全泥氰化工艺尾水开展100t/d工业试验研究,开发纳滤、反渗透二段浓缩铜银络合离子工艺,通过置换、中性萃取、酸性反萃、电积全新工艺技术,在不改变尾水理化性能的条件下,实现了活化游离氰根,提高金、银浸出率,综合回收电积铜的目的。     

酸浸—萃取提金新工艺的生产实践

介绍祥云飞龙公司采用萃取方法从银电解阳极泥中提取黄金的生产实践。当金氯酸溶液酸度控制在2.0mol/L时,萃余液含金可控制在5 mg/L以下。该工艺操作简单,投资费用低,金回收率在99%以上,产品质量优异,经济效益良好。     

分金渣中银的提取及氯化银制备

提出一种从分金渣中提取银及制备氯化银的工艺。在下述最佳工艺条件下:亚硫酸钠浓度220g/L、pH=8.0、反应温度40℃、反应时间60min、液固比L/S=10,银浸出率达到98.3%;含银浸出液加硫酸控制pH为4.0制备出纯度为99.9%的氯化银,银直收率达到98.2%。