高等数学教学中渗透数学建模思想的研究

数学建模是数学与应用的桥梁,分析了在高等数学教学中渗透数学建模思想的原因,同时讨论了在高等数学教学中渗透数学建模思想的实施方法.     

AM60B镁合金微弧氧化膜的电化学腐蚀行为

在硅酸盐体系中对AM60B镁合金进行微弧氧化处理,采用循环伏安(CV)法、Tafel极化曲线和电化学阻抗谱(EIS)研究膜层在3.5% NaCl介质中的电化学腐蚀行为.结果表明:AM60B镁合金经微弧氧化处理后,膜层耐蚀性得以显著提高.相比低电压下的膜层,高电压下获得膜层微孔略大,但微孔数量明显较少,厚度显著增加,这使得膜层在整个腐蚀过程中呈现了极强的电阻性和优异的耐蚀能力,甚至测试结束时腐蚀介质仍未渗透至膜基面,而低电压下处理得到的膜层,腐蚀介质已渗透至膜基面且侵蚀了基体.     

全球核能科技前沿综述

 讨论了核能前沿科技领域所取得的科技研究与重要工程项目进展，重点介绍了核电建设与发展、小型模块堆技术、聚变反应堆、空间动力堆、事故容错燃料，数值反应堆等方面的研究及开发进展。在海、陆、空均有良好应用前景的小型反应堆，将在传统商用核电以外开辟核能利用的新天地。而先进燃料设计、高精度数值模拟等技术则是未来核能安全保障的重要发展方向。随着技术的进一步革新和技术路线的多样化，呈多元化发展态势的核能预期仍将在全球能源结构中占据重要地位。     

丙酸盐对厌氧氨氧化除氮性能及群落结构的影响

为了探究有机碳对厌氧氨氧化的长期影响, 向厌氧氨氧化膜生物反应器中添加不同浓度的丙酸钠, 研究对反应器的除氮效能以及微生物的种群结构和功能变化。结果表明: 反应器主要的脱氮过程由CandidatusBrocadia完成, 当丙酸钠浓度为100 mg/L时, 反应器中由于异养细菌的生长, 可实现碳氮的同步去除, 平均总氮去除率可达91.9%。当丙酸钠浓度为200 mg/L 时, 对Candidatus Brocadia的抑制作用导致反应器除氮性能下降, Candidatus Brocadia的丰度降至41.2%, 总氮去除率降至 78.8%。在有机碳抑制作用解除后, 反应器的除氮性能恢复为86.8%, Candidatus Brocadia丰度增加到54.0%, 但群落多样性下降, 属水平的微生物组成有较大的改变。     

2019年先进纤维复合材料研发热点回眸

 高性能纤维复合材料作为典型的先进纤维复合材料，无论在军用还是民用领域都拥有极为广泛的应用前景，近年来已成为世界各国研究的热点和重点。通过回顾2019年全球范围内高性能纤维复合材料在新产品、新工艺以及新市场等方面取得的科技进展，对美国、日本、欧洲和中国高性能纤维复合材料的研究重点进行了总结并分析了未来高性能纤维复合材料的发展趋势。     

FeCo-based hybrid MOF derived active species for effective oxygen evolution

Metal-organic frameworks(MOFs) have been regarded as promising catalyst materials due to the richness of coordinately unsaturated metal sites on the surface,which can act as catalytic active centres.In this study,a hybrid MOF material composed of Fe-based MOF and Co-based MOF was prepared with the involvement of graphene oxide nanosheets as additive.It was demonstrated that the hybrid MOF materials showed much higher electro-catalytic activity towards oxygen evolution than the single-phase counterparts.To drive current density of 10 mA cm~(-2),the hybrid CoFe-based MOF only needed an over potential of 290 mV in 1 M KOH.The catalytic activity could sustain for a longer time with only slight current density decrease.During oxygen evolution operation,the MOF catalyst evolved into catalytic active species but kept well the microscale sheet-like structure.It is thus believed that this study will provide an avenue for the development of advanced electrocatalysts.     

Acyl-chloride functionalized graphene oxide chemically grafted with hindered phenol and its application in anti-degradation of polypropylene

In this study,graphene oxide (GO) nanosheets were first functionalized by the acyl-chloride reaction and then reacted with hindered phenol (HP) to obtain HP grafted GO (GO-g-HP).The GO-g-HP prepared under the optimized condition exhibited a high efficiency against both thermal and photo oxidation of isotactic polypropylene (iPP).GO-g-HP exhibited a much better anti-aging efficiency than that of HP and GO used individually or that of their physical mixture.The outstanding anti-aging effect of GO-g-HP was attributed to the excellent synergistic effect produced between the chemically bonded GO and HP,which resulted in an improved oxygen barrier property of GO and excellent utilization of the free radical scavenging capability of GO and HP.Also,thanks to the grafting of HP on GO,the physical loss of HP,which was one of the main shortcomings for traditional small molecular antioxidants,was largely suppressed.It is expected that the GO-g-HP prepared can well meet the requirement of long-term applications of polymers in some harsh service conditions.     

污泥高级厌氧消化前后的热风对流干燥特性

利用热风对流干燥技术对脱水污泥及高级厌氧消化后的污泥进行了对流干燥试验。研究了风温、风速和样品厚度对污泥的干燥效果。结果表明,在相同的工况下,高级厌氧消化后的污泥的干燥效率高于脱水污泥的干燥效率。在风温、风速和污泥厚度分别在120℃、6 m/s和10 mm的工况下,脱水污泥的最高干燥速率为80.7 mg/(g·min),而厌氧消化沼渣的最高干燥速率为486.2 mg/(g·min),厌氧消化沼渣的干燥速率是脱水污泥干燥速率的6倍。在实际处理中,污泥可考虑先经过高级厌氧消化之后,再通过对流干燥达到减量的目的。     

电压对纯镁微弧氧化膜层电化学腐蚀行为的影响

采用循环伏安(CV)、动电位极化(Tafel)和电化学阻抗谱(EIS)技术、结合纯镁微弧氧化膜微观形貌,研究电压对膜层电化学腐蚀行为的影响.结果表明:电压对膜层耐蚀性影响显著,随着电压升高,膜层耐蚀性增强,这是因为较厚的膜层厚度为抵御腐蚀介质的侵蚀提供了良好的物理屏障.在整个腐蚀试验过程中,高电压下制备的膜层经历三个阶段:腐蚀介质逐渐渗入膜层,腐蚀介质渗透膜层到达膜基面侵蚀基体,腐蚀产物填充微孔和微裂纹等缺陷.相比而言,低电压下制备的膜层随着浸泡时间的延长,膜层外部疏松层和内部致密层的电阻均逐渐减小,致使耐蚀性降低,最终膜层完全失效.     

分子水氧化催化剂及其光电催化分解水研究进展

 总结了近年来基于不同第一过渡系列金属的分子水氧化催化剂，包括贵金属分子水氧化催化剂和非金属分子水氧化催化剂；以及常用的氧化物半导体电极材料，例如α-Fe₂O₃、WO₃和BiVO₄等。概述了目前分子水氧化催化剂在电极表面的负载方式，包括物理吸附方式、共价键结合方式、分子催化剂修饰吸附基团方式、静电作用和π-π堆积作用等。提出构建高效稳定的光致水分解分子器件需要解决的问题，从而实现利用太阳能大规模裂解水制备清洁能源的设想。