Flow influenced electrochemical corrosion of nickel aluminium bronze – Part I. Cathodic polarisation

The cathodic polarisation behaviour of CA 104 nickel aluminium bronze (NAB) has been examined in fully characterised seawaters (filtered and artificial) using the rotating disc electrode (RDE) and the rotating cylinder electrode (RCE). Linear sweep voltammetry and a potential step, current transient technique were used to examine the charge transfer and mass transfer controlled cathodic response as a function of both laminar and turbulent fluid flow. For freshly polished surfaces, the rate of irreversible charge transfer controlled oxygen reduction is controlled by the exchange of a single electron and hydrogen evolution is only significant at potentials more negative than approximately –1.0 V vs. the saturated calomel electrode (SCE).     

Cobalt nanoparticle decorated N-doped carbons derived from a cobalt covalent organic framework for oxygen electrochemistry

The low cost and highly efficient construction of electrocatalysts has attracted significant attention owing to the use of clean and sustainable energy technologies. In this work, cobalt nanoparticle decorated N-doped carbons (Co@NC) are synthesized by the pyrolysis of a cobalt covalent organic framework under an inert atmosphere. The Co@NC demonstrates improved electrocatalytic capabilities compared to N-doped carbon without the addition of Co nanoparticles, indicating the important role of cobalt. The well-dispersed active sites (Co–N_x) and the synergistic effect between the carbon matrix and Co nanoparticles greatly enhance the electrocatalytic activity for the oxygen reduction reaction. In addition, the Co content has a significant effect on the catalytic activity. The resulting Co@NC-0.86 exhibits a superb electrocatalytic activity for the oxygen reduction reaction in an alkaline electrolyte in terms of the onset potential (0.90 V), half-wave potential (0.80 V) and the limiting current density (4.84 mA·cm^–2), and a high selectivity, as well as a strong methanol tolerance and superior durability, these results are comparable to those of the Pt/C catalyst. Furthermore, the superior bifunctional activity of Co@NC-0.86 was also confirmed in a home-built Zn-air battery, signifying the possibility for application in electrode materials and in current energy conversion and storage devices.     

CoSe2@NF双功能电催化剂用于高效碱性全解水

开发用于水分解的高效稳定、低成本非贵金属电催化剂，特别是在同一电解质中对阴极的析氢反应(HER)和阳极的析氧反应(OER)都具有高效作用的电催化剂是一项挑战。以六水合硝酸钴、尿素、氟化铵和硒粉为原料，采用水热和高温固相法在镍网上原位构筑了CoSe2@NF，采用XRD、XPS、SEM和TEM对CoSe2@NF进行物相分析和形貌表征，并在碱性电解液中对CoSe2@NF的电催化析氧和析氢性能进行了测试。结果表明，表面粗糙的串珠状纳米线结构极大地增加了CoSe2有效活性位点的数量。该催化电极在OER和HER中均表现出高而稳定的催化活性。将CoSe2@NF作为全解水槽的阴阳极，在1.6 V槽电压下即可产生10 mA/cm2的电流，并可在1.7 V的电压下稳定运行100 h。这项研究为全解水提供了一种经济有效的解决方案.     

生物质硅炭增强改性氢化丁腈橡胶的性能及老化规律

以生物质硅炭(Si/CB)取代部分N550炭黑为补强剂、HNBR为基体制备了生物质硅炭改性的HNBR复合材料.研究了硅炭对HNBR的补强行为,高温真空介质中橡胶的热老化行为及主链老化结构的演变.与传统炭黑的增强效果相比,生物质硅炭增强的HNBR表现出更好的韧性、撕裂强度、较低的永久变形及高温力学性能.160℃下老化20...     

NiZnCe复合氧化物的制备及其催化氧化正丁烷脱氢性能

采用溶胶凝胶法制镍锌铈（NiZnCe）复合氧化物催化剂,分别考察了NiZnCe复合氧化物催化剂中Zn和Ce含量对正丁烷氧化脱氢性能的影响。研究结果表明,NiZn_0.5Ce_0.3催化剂的转化率和烯烃选择性较高。采用H₂-TPR、XPS及TPRO的表征方法来揭示催化剂中氧移动循环的不同步骤对催化剂性能的影响。表征结果显示,Ce元素的引入对催化剂的氧移动性产生较大的影响,且催化剂性能与氧容量（参与反应的催化剂中的氧量）呈正相关。此外,Ni与Ce的相互作用导致了Ni阳离子化合价和可接受电子能力的提高,活性Ni更容易吸附活性氧物种,金属与氧气的循环往复反应更活泼。     

亲油型聚结滤芯饱和度预测模型研究

纤维聚结滤芯广泛用于压缩空气净化、发动机曲轴箱通风、加工和切割等一系列工艺过程中,用于除去气流中的液体气溶胶颗粒。由于聚结滤芯饱和度对于过滤效率及阻力具有重要影响,因此建立饱和度与滤材参数及操作条件之间的关系将有助于优化滤芯结构并提高过滤性能。目前实际工业用聚结滤芯通常由多层微米级玻璃纤维材料组成,然而现有计算模型无法用于此类滤芯的饱和度预测。因此,本文基于多种常用亲油型聚结滤芯压降及饱和度实验测试结果,根据“跳跃-通道”模型及毛细管理论建立了新的饱和度预测模型。通过与大量已发表文献数据对比发现,当饱和值大于0.2时,预测值与实验结果吻合度较好,相对偏差≤20%。随着饱和度的降低,滤芯润湿区域和非润湿区域之间界限逐渐明显,此时无需对毛细管半径进行修正。然而,新模型仍然要依靠压降测量值进行计算,这一问题需在后续工作中加以解决。     

Bipolar resistive switching behavior and conduction mechanisms of composite nanostructured TiO2/ZrO2 thin film

In this work, TiO₂/ZrO₂ bilayer thin film was prepared on fluorine doped tin oxide (FTO)/glass substrates by using a simple and low-cost chemical solution deposition method. Reproducible bipolar resistive switching (RS) characteristics in Au/TiO₂/ZrO₂/FTO/glass devices are reported in this work. TiO₂/ZrO₂ bilayer thin films prepared in this work shows reversible bipolar resistive switching and unidirectional conduction performances under applying voltage and these special performances of TiO₂/ZrO₂ bilayer thin films was first reported. Obvious resistive switching performance can be observed after setting a compliance current, the ratio of high/low resistance reached about 100 at a read voltage of +0.1V and −0.1V and the RS properties showed no obvious degradation after 100 successive cycles tests. The resistive switching characteristics of Au/TiO₂/ZrO₂/FTO/glass device can be explained by electron trapping/detrapping related with the vacancy oxygen defects in TiO₂/ZrO₂ bilayer thin film layer. According to slope fitting, the main conduction mechanisms of the sample are Ohmic and Space charge limited current mechanism.     

骨组织工程支架材料

寻找理想的支架材料是目前骨组织工程研究的热点。本文阐述了用于骨组织丁程支架材抖的天然生物衍生材料、聚合物类材料、陶瓷材料及其复合材料等的研究现状,分析了这些材料的优缺点,并展望了骨组织工程支架材料的发展趋势。     

一种新型葡萄糖基化竹红菌素的合成和ESR研究

以巯基乙酸取代的竹红菌乙素和氨基葡萄糖为反应物,只用一步就合成了一种新型葡萄糖修饰的竹红菌乙素.氨基葡萄糖的取代改善了竹红菌乙素的水溶性及其在光疗窗口的吸收,并保持了其产生1O2、O2·-、·OH和半醌负离子自由基的光化学活性.     

骨组织工程支架材料磷酸钙双相生物陶瓷的研究进展

双相磷酸钙(biphasic calcium phosphate,BCP)生物陶瓷材料在整型外科领域是一类重要的骨修复材料。该材料由稳定相羟基磷灰石(hydroxyapatite,HA)和可溶解相β-磷酸三钙(β-tricalcium phosphate,β-TCP)双相平衡优化得到,其生物活性及生物降解性可调。模拟人体自然骨结构的多孔型BCP适宜细胞及骨组织的长入,是一类优异的骨组织工程支架材料。概述了BCP生物陶瓷材料的研究历史、制备工艺及材料表征;评价了多孔型BCP陶瓷的孔隙结构、力学性能及生物学性能;综合了多孔型BCP陶瓷作为骨组织工程支架材料的研究方向;并展望了组织工程化的BCP支架材料的研究未来。