Hierarchically porous N-doped carbon nanofibers derived from ZIF-8/PAN composites for benzene adsorption

Coupling with electrospinning technique, metal–organic-frameworks (MOFs)-derived porous carbon fibers exhibit a great potential application in the adsorption of volatile organic compounds (VOCs) because of their huge surface area, high porosity, as well as sufficient heteroatom-doped active sites. In this work, the hierarchically porous N-doped carbon nanofibers are obtained after the pyrolysis of zeolite imidazole framework-8 and polyacrylonitrile (ZIF-8/PAN) composite fibers synthesized by electrospinning method. The N-doped carbon nanofibers fabricated in N₂ atmosphere (N-CF-N₂) present an enhanced adsorption capacity of 694 mg/g for benzene because of the synergistic effect of the hierarchically porous structure and the abundant N-species-containing active sites. It is also interesting that the N-doped hierarchical carbon nanofibers fabricated in Ar atmosphere (N-CF-Ar) exhibit a low benzene adsorption as compared with the N-CF-N₂, which can be attributed to the porous structure damage caused by the bombardment of heavy Ar atoms on the pore shells during the pyrolysis. These results not only show a promising application of the as-fabricated N-CF-N₂ in adsorption of VOCs for air purification due to its merit of cost-efficient, large-scale production, and excellent adsorption capacity, but also expand the potential of electrospinning technology and composite fibers in volatile organic gas adsorption.     

Antibacterial self-healing anticorrosion coatings from single capsule system

It is highly desirable to develop self-healing anticorrosion coatings with enhanced antibacterial function to prevent the scratched area to be fouled or corroded in harsh environments. Herein, we report antibacterial self-healing anticorrosion coatings via the simple incorporation of the easily synthesized single polymer microcapsule system. Well-defined polymer microcapsules containing isophorone diisocyanate (IPDI) as a healing agent and 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) as antibacterial molecules were synthesized by one-pot polymerization. The diameter and core fraction were around 30 μm and 90%, respectively. The active DCOIT content in the core material could be precisely controlled by adjusting the DCOIT/IPDI feeding ratio. The DCOIT/IPDI microcapsules-embedded protective coating exhibits an adaptive self-healing anticorrosion property, as shown by electrochemical test under the condition of the salt-water immersion. Furthermore, the self-healing coating showed efficient antibacterial function against Escherichia coli and Pseudomonas aeruginosa, which is due to the released active biocide molecules on the damaged surfaces. In contrast to other systems, this single capsule system without any catalyst is perspective for extending the service time of the antibacterial self-healing materials in harsh environment.     

Engineering all-aromatic polyamide surface from hydrophilic to superhydrophobic and the accelerated strategy

Being a new kind of nanomaterials, aromatic polyamide nanofibers (ANF) have been much highlighted in recent studies. We here demonstrate an isopropyl alcohol (IPA) accelerated chemical cleavage on poly (p-phenylene terephthalamide) chopped fibers, which provides an efficient preparation method of ANF. The comprehensive study on the processes accelerated by different alcohols revealed that the preparation time of ANF in the mixed medium of dimethyl sulfoxide (DMSO)-alcohol (20:1 in volume) was shorten to 45 min and 75 min for methanol (ethanol) and isopropanol, respectively. However, the nanofibers prepared in DMSO-IPA exhibited the minimum in axial and radial dimensions, providing the finest and most uniform diameter of 16 nm. The corresponding ANF films through vacuum assisted filtration also showed the highest tensile strength of 150 MPa, in comparison with those of the ANF films prepared using other alcohols, which were about 110 MPa. Furthermore, ANF/silicon hybrid films were prepared by the ionic ring-opening reaction followed by the alkoxysilane condensation and nanoparticle fabrication. By changing the organo functional groups in the alkoxysilane, the surface of the films were adjustable in a wide contact angle range from 56° (hydrophilic) to 150° (superhydrophobic), suggesting the amendable interfacial properties potential applicable to composite fabrication with most of the resin matrix.     

高级氧化技术降解抗生素及去除耐药性的研究进展

近年来由于抗生素滥用而导致的水污染日益严重,抗生素残留及耐药性已成为当今社会面临的最严峻挑战之一。高级氧化工艺以其快速的反应速率和良好的处理效果,越来越多地被用于治理含抗生素的废水。本文首先阐述了抗生素的污染现状;其后根据起主导作用的自由基种类,分类对比了传统高级氧化和过硫酸盐高级氧化处理抗生素及耐药性的特征,深入分析了过硫酸盐高级氧化的反应机理,重点介绍了热活化、紫外活化、零价铁及其改性活化和电活化等不同活化过硫酸盐的方式,并研究总结了这些技术用于处理抗生素及其耐药性的降解效果和进展;综合分析了目前高级氧化降解抗生素及去除耐药性的环境影响因素和存在的问题;最后对高级氧化的未来发展进行了展望。     

分段长初级双边直线感应电动机建模分析

分段长初级双边直线感应电动机(LP-DSLIM)系统由若干段单元电机串联或并联组成,为准确描述次级运动过程中单元电机的推力等状态变化和过分段时的暂态过程,该文提出了一种新型单元电机数学模型及分段LP-DSLIM系统模型.首先,对分段LP-DSLIM系统的特点进行分析,通过引入虚拟次级板将每段单元电机耦合的次级延长至与初级等长,以使单元电机初级、次级之间始终保持全耦合;然后,结合耦合因数得到实际次级磁链和初级磁链,以此推导得到新型单元电机数学模型,并基于此建立串联供电和并联供电的分段LP-DSLIM系统模型;最后,有限元计算和实验结果验证了提出的新型单元电机数学模型和分段LP-DSLIM系统模型的正确性.     

光储微网系统多目标协调控制策略

基于光伏储能+电采暖的光储微网系统可以有效解决西部农村社区清洁能源供应量不足问题.为了提高光储微网系统的能量控制效果和工程实用性能,该文通过构建包含电力费用、储能系统荷电状态(SOC)、供暖舒适度等变量的多目标函数,提出一种计算量较低的储能与电热负荷多目标协调控制策略.为了简化目标函数求解过程,引入求导和单调性分析等优化方法.为了降低系统计算量,以住宅建筑保温性能为评价标准,提出一种带宽能量控制模式,降低了被控单元的控制频率,提高了算法的工程应用价值.搭建Matlab/Simulink仿真平台,依据西部青海省某示范光储微网系统实际数据,仿真对比分析基于传统能量控制策略和基于多目标协调控制策略的光储微网系统性能,验证该文所提控制策略的有效性和优越性.     

含电动汽车充电的配电网运行可靠性评估算法

现有方法难以对不同充电状态下的配电网运行状态进行准确评估,为此设计含电动汽车充电的配电网运行可靠性评估算法.通过计算配电网运行情况与配电网元件使用状态,实现配电网运行可靠性评估指标的选取.同时,设定充电周期,计算电动汽车充电功率,并将此作为评估参考因素之一.采用模拟法构建评估模型,将运行可靠性评估指标与电动汽车充电功率融入此模型中,实现对含电动汽车充电的配电网运行可靠性的评估.算例测试结果表明,在慢充和快充状态下的评估计算响应时间明显低于现有方法,并且评估结果的准确性较高.算法更适用于电动汽车配电网运行状态的评估.     

TiO2薄膜电极的制备及光电催化性能

为了得到光电化学性能稳定、光催化活性好、制备方法简便的TiO2光电极,采用涂覆法制备了纳米TiO2薄膜光电极.XRD,SEM结果表明电极上涂覆的TiO2的晶型为锐钛型,纳米TiO2在电极表面分布均匀,薄膜厚度在10μm左右,且电极表面有一定的粗糙度.交流阻抗图谱分析显示TiO2电极在光照下能进行光电化学反应.应用于20mg/L苯酚溶液的降解中,结果表明,该电极光电催化降解性能优于光催化降解性能,电场在降解过程中发挥了作用;对照态光氧化过程基本无化学反应发生;暗态下电极上也无吸附现象;反应后电极无剥落损伤.     

Sr对Al-Si-Mg铸造合金中Mg2Si相结晶行为影响的研究

采用光学显微镜和扫描电镜观察了不同Sr量Al 11 6 %Si 0 4%Mg合金的组织变化 ,并分析了Sr的存在对Mg2 Si相结晶行为的影响。在未完全变质合金中 ,Mg2 Si相以网络状或笋状等形式存在 ,与共晶Si片之间存在附着生长关系。而在完全变质合金中 ,Mg2 Si相以细小的颗粒相形式孤立地存在于共晶团边界上 ,数量极少。Sr的存在对Mg2 Si相凝固结晶行为产生了重要的影响 ,这与枝晶α的数量和共晶Si的变质程度等因素有关     

镍阳极氧化膜形成和破坏过程的光电化学响应

测定了镍表面阳极氧化膜在ｐＨ＝８．４硼砂－硼酸缓冲溶液中不同电位下的光电流响应。基于阻抗测量结果的计算表明，钝化膜的平带电位和载流子密度分别为－０．６８Ｖ和１．３×１０（２０）ｃｍ（－３）。对钝化膜和高价氧化膜在形成、生长和破坏过程中的光电流变化进行了现场监测。