Electrocatalytic activity of LaSr3Fe3O10 and LaSr3Fe3O10-GO towards oxygen reduction reaction in alkaline medium

Oxygen reduction reaction(ORR) plays a critical role in many energy conversion and storage processes.Therein, a comparative study of the electrocatalytic activity for ORR in 0.1 mol/L KOH solution was conducted using layered perovskite-like LaSr_3 Fe_3 O_(10) and LaSr3 Fe_3 O_(10)-graphene oxide(GO) composite as electrodes. Linear sweep voltammetry(LSV) results show that the LaSr3 Fe_3 O_(10)-GO hybrid exhibits higher current density, a more positive onset potential(-0.15 V vs. Hg/HgO) in comparison with LaSr_3 Fe_3 O_(10).The value of the overall transferred electrons for both catalysts implies a dominant two electron process for ORR. Both catalysts under alkalic conditions exhibit a two-step Tafel slope, suggesting a change in the reaction mechanism for ORR. The composite electrode exhibits a higher ORR current density, but inferior durability performances in relative to the LaSr_3 Fe_3 O_(10) electrode.     

A Versatile Theranostic Nanoemulsion for Architecture‐Dependent Multimodal Imaging and Dually Augmented Photodynamic Therapy

To design a clinically translatable nanomedicine for photodynamic theranostics, the ingredients should be carefully considered. A high content of nanocarriers may cause extra toxicity in metabolism, and multiple theranostic agents would complicate the preparation process. These issues would be of less concern if the nanocarrier itself has most of the theranostic functions. In this work, a poly(ethylene glycol)‐boron dipyrromethene amphiphile (PEG‐F₅₄‐BODIPY) with 54 fluorine‐19 (¹⁹F) is synthesized and employed to emulsify perfluorohexane (PFH) into a theranostic nanoemulsion (PFH@PEG‐F₅₄‐BODIPY). The as‐prepared PFH@PEG‐F₅₄‐BODIPY can perform architecture‐dependent fluorescence/photoacoustic/¹⁹F magnetic resonance multimodal imaging, providing more information about the in vivo structure evolution of nanomedicine. Importantly, this nanoemulsion significantly enhances the therapeutic effect of BODIPY through both the high oxygen dissolving capability and less self‐quenching of BODIPY molecules. More interestingly, PFH@PEG‐F₅₄‐BODIPY shows high level of tumor accumulation and long tumor retention time, allowing a repeated light irradiation after a single‐dose intravenous injection. The “all‐in‐one” photodynamic theranostic nanoemulsion has simple composition, remarkable theranostic efficacy, and novel treatment pattern, and thus presents an intriguing avenue to developing clinically translatable theranostic agents.     

基于多视图立体视觉的沙堆三维尺寸测量研究

利用从运动中恢复结构方法(SFM),提出了一种基于多视图立体视觉的沙堆三维重建及三维尺寸测量方法。首先根据SFM方法的求解不稳定特点,结合光束平差法对SFM求解过程进行分析及优化;其次针对SFM重建结果为稀疏点云的问题,利用基于面片的稠密重建算法重新生成稠密的三维点云,再利用泊松算法对密集点云进行三维曲面重建;最后获得模型的三维尺寸信息。对某建筑工地的沙堆进行了三维尺寸的测量实验,实验结果验证了该方法的有效及可行性,提高了重建能力及精度,同时考虑了目标实际测量误差与重建误差,能够满足实际智能测量的应用需求。     

轻量级电驱水下机械臂设计与运动学分析

设计了一款四功能水下机械臂，并对驱动关节进行了模块化设计和密封测试。为了保证水下机械臂的可靠性，在水下机械臂水下测试前，进行了强度校核和模态分析。为了验证水下机械臂的性能，通过 Ｄ- Ｈ法建立了其运动学模型，在此基础上分别进行了正、逆运动学分析。此外还采用蒙特卡洛法，在正运动学分析的基础上研究了工作空间特点。研究结果将为进一步的运动控制提供有益的帮助。     

城市污水厂剩余污泥对水中F-的吸附性能研究

利用城市污水处理厂的剩余污泥对水中F-进行吸附处理,通过污泥投加量、F-初始质量浓度、时间、pH等反应条件的研究,探讨除氟效果和影响因素。结果表明,室温下,污泥对F-的吸附在60 min后达到平衡;20 g/L的污泥投加量对10 mg/L含氟水的F-去除率可达83.1%;污泥可在3~10的较大pH范围内保持稳定的除氟效果。准二级动力学模型很好地拟合了污泥对F-的吸附行为,Langmuir和Freundlich模型均符合污泥对F-的吸附特性,热力学参数的计算表明该吸附过程是自发的放热反应。     

高瓦斯矿井U型通风工作面瓦斯治理技术

针对李雅庄煤矿U型通风工作面上隅角及回风流瓦斯浓度高、瓦斯治理难度大的问题，根据工作面瓦斯来源及在采空区三带的运移储存规律，李雅庄煤矿开展了本煤层抽采工艺优化和裂隙带抽采技术研究。对本煤层钻孔封孔深度、联孔工艺、管路连接方式等进行优化，钻孔抽采浓度由抽采4个月后降低到9%提高到抽采10个月后维持在19%；通过调整裂隙带钻孔布置方式、优化钻孔布孔层位、采取下筛管护孔等技术措施，裂隙带钻场最高瓦斯抽采纯流量达13.6 m³/min，平均瓦斯抽采纯流量达8 m³/min，2个钻场联合抽采瓦斯纯流量在13 m³/min以上；取消了瓦斯措施巷、井下移动泵和上隅角风帘，上隅角和回风流平均瓦斯浓度分别控制在0.5%和0.4%以下，对高瓦斯矿井U型通风工作面瓦斯治理有借鉴意义。     

复合固体推进剂中固体填料的安息角测试与仿真

复合固体推进剂含有固体颗粒较多，离散单元法是一种适合固体推进剂生产过程数值仿真的有效方法，颗粒物料的接触参数是保证离散单元法仿真精度的关键。本文以复合固体推进剂的主要组分铝粉和高氯酸铵固体颗粒为研究对象，通过实验测试获得了相关物料的安息角，利用专业离散元软件EDEM仿真模拟了安息角测试实验过程，建立了物料安息角与接触参数之间的联系。研究表明，滚动摩擦系数和滑动摩擦系数越大，安息角越大，物料流动性越差。对比仿真与实验结果，通过逆向反推法确定了物料的滑动摩擦系数和滚动摩擦系数两个关键接触参数。铝粉与高氯酸铵1∶2混合颗粒的滑动摩擦系数为0.2，滚动摩擦系数为0.05。为固体推进剂加工生产过程离散元数值仿真提供了关键基础数据。     

Efficient construction and enriched selective adsorption-photocatalytic activity of PVA/PANI/TiO2 recyclable hydrogel by electron beam radiation

Enriched selective adsorption-photocatalytic activity of Poly (vinyl alcohol)/Polyaniline/TiO₂ (PVA/PANI/TiO₂, noted as PAT) recyclable hydrogel photocatalyst with 3D structures were prepared by self-assembling and electron beam radiation crosslingking method. TiO₂ nanoparticles were successfully introduced into the 3D matrix of the PVA/PANI hydrogel and manifested by FTIR, TG, XRD, XPS, and SEM-EDS. The microstructure of PAT was characterized further by SEM, TEM, and BET. The highly selective adsorption-photocatalytic activity of PAT was tested by the degradation of cationic or anionic dye and reduction of heavy metal ion in a closed and flow system under UV light irradiation. The results showed that PAT had a highest selective adsorption-photocatalytic performance at the appropriate content of PVA (10 wt %), TiO₂ (15 wt %) and suitable radiation dose (50 kGy), which could be attributed to the synergistic effect of excellent selective adsorption and effective photocatalytic degradation. The mechanism of selective adsorption-photocatalytic on PAT was revealed synchronously in this study. Particularly, the novel PAT photocatalyst with 3D network structure also affords ease of separation and recycling, which is beneficial to water purification in a flow system. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48516.