Co?N graphene encapsulated cobalt catalyst for H2O2 decomposition under acidic conditions

Hydrogen peroxide (H₂O₂) has been listed as one of the 100 most important chemicals in the world. However, huge amount of residual H₂O₂ is hard to timely decomposed into O₂ and H₂O under acidic condition, easily resulting in explosion hazard. Here, we reported a core–shell structure catalyst, that is graphene with Co N structure encapsulated Co nanoparticles. Co N graphene shell serves as the active site for the H₂O₂ decomposition, and Co core further enhance this decomposition. Benefiting from it, the H₂O₂ decomposition were close to 100% after 6 cycles without pH adjustment, which increased 6 orders of magnitude compared with no catalyst. At the same time, the O₂ generation reached 99.67% in 2 h with little metal leaching, and ·OH has been greatly inhibited to only 0.08%. This work can cleanly remove H₂O₂ with little deep oxidation and protect the process of H₂O₂ utilization to achieve a safer world.     

毫米波三维异质异构集成技术的进展与应用

三维异质异构集成技术是实现电子信息系统向着微型化、高效能、高整合、低功耗及低成本方向发展的最重要方法,也是决定信息化平台中微电子和微纳系统领域未来发展的一项核心高技术。文章详细介绍了毫米波频段三维异质异构集成技术的优势、近年来的发展趋势以及面临的挑战。利用硅基MEMS 光敏复合薄膜多层布线工艺可实现异质芯片的低损耗互连,同时三维集成高性能封装滤波器、高辐射效率封装天线等无源元件,还能很好地处理布线间的电磁兼容和芯片间的屏蔽问题。最后介绍了一款新型毫米波三维异质异构集成雷达及其在远距离生命体征探测方面的应用。     

Fe3O4-carbon spheres core–shell supported palladium nanoparticles: A robust and recyclable catalyst for suzuki coupling reaction

Suzuki-Miyaura (S-M) is regarded the most powerful way for synthesis biaryls, triaryls, or incorporating of substituted aryl moieties in organic preparation by the cross-coupling of aryl boronic acid with aryl halides using the Pd catalyst. This work reports the combining of the hydrothermal and microwave-assisted protocol to convert the glucose to magnetic carbon spheres (Fe₃O₄-CSPs) decorated with Pd nanoparticles (NPs) as the catalyst for Suzuki-Miyaura cross-coupling reactions. The physicochemical properties in the produced composite were examined using FESEM, HRTEM, nitrogen isotherms, Raman spectroscopy, FTIR, XPS, and XRD. The as-fabricated composite Pd/Fe₃O₄-CSPs is mostly spherical with a core–shell structure and possesses a great surface area of 253.2 m²·g^-1. Its catalytic performance demonstrates that the composite has excellent stability and high tolerance Suzuki-Miyaura cross-coupling reactions in 30 min at 80 ℃. Both activated and deactivated aryl halides provided excellent yield. The as-fabricated catalyst was recycled for up to four catalytic cycles without a substantial decline in performance. Moreover, this research offers a facile roadmap for synthesizing Pd/Fe₃O₄-CSPs composites and promoting the practical implementation of Pd/Fe₃O₄-CSPs catalysts for organic transformation processes.     

羟基磷灰石作为催化材料的研究进展

羟基磷灰石(HAP)由于具有无毒性、生物相容性、热稳定性、吸附性、离子交换性、结构稳定性等,因而被广泛应用到催化剂的制备中。作为一种新型催化材料,HAP的特殊晶体结构对一些反应表现出催化活性,并且经过改性、负载等方法处理过后的HAP催化剂显示出独特的催化优势。基于近年来HAP在催化邻域的发展,综述了HAP作为催化材料在降解污染物、制氢、药物合成、还原氮氧化物等反应中的不同应用,并对未来的研究方向进行了展望。     

Ir(III) and Ru(II) Complexes in Photoredox Catalysis and Photodynamic Therapy: A New Paradigm towards Anticancer Applications

Individually, photoredox catalysis (PC) and photodynamic therapy (PDT) are well-established concepts that have experienced a remarkable resurgence in recent years, leading to significant progress in organic synthesis for PC and clinical approval of anticancer drugs for PDT. But, very recently, new photoredox catalyst systems based on Ir(III) and Ru(II) complexes have garnered significant interest because they can simultaneously be used as PDT agents apart from their demonstrated PC activity. This highlight discusses the unique PC behavior of emerging Ir(III)- and Ru(II)-based systems while also examining their potential PDT activity in cancer treatment.     

Helices on Interdomain Interface Couple Catalysis in the ATPPase Domain with Allostery in Plasmodium falciparum GMP Synthetase

GMP synthetase catalyses the conversion of XMP to GMP through a series of reactions that include hydrolysis of Gln to generate ammonia in the glutamine amidotransferase (GATase) domain, activation of XMP to adenyl-XMP intermediate in the ATP pyrophosphatase (ATPPase) domain and reaction of ammonia with the intermediate to generate GMP. The functioning of GMP synthetases entails bidirectional domain crosstalk, which leads to allosteric activation of the GATase domain, synchronization of catalytic events and tunnelling of ammonia. Herein, we have taken recourse to the analysis of structures of GMP synthetases, site-directed mutagenesis and steady-state and transient kinetics on the Plasmodium falciparum enzyme to decipher the molecular basis of catalysis in the ATPPase domain and domain crosstalk. Our results suggest an arrangement at the interdomain interface, of helices with residues that play roles in ATPPase catalysis as well as domain crosstalk enabling the coupling of ATPPase catalysis with GATase activation. Overall, the study enhances our understanding of GMP synthetases, which are drug targets in many infectious pathogens.     

基于LBSN动态异构网络的时间感知兴趣点推荐

随着基于位置社交网络(Location-Based Social Network,LBSN)的快速发展,兴趣点(Point-Of-Interest,POI)推荐可以帮助人们发现有趣的并吸引人的位置。针对签到数据的稀疏性和用户兴趣的动态性等挑战性问题,提出了基于LBSN动态异构网络的时间感知兴趣点推荐算法。在LBSN异构网络模式中增加会话节点类型。通过动态元路径,在用户和兴趣点语义关系之间有效地融入时间信息、位置信息和社交信息等。设置了用户-兴趣点之间的动态元路径集,并提出了动态路径实例的偏好度计算方法。采用矩阵分解模型对不同动态偏好矩阵进行矩阵分解。根据不同动态元路径的用户特征矩阵和兴趣点特征矩阵,获取用户在目标时间访问兴趣点的推荐列表。实验结果表明,与其他兴趣点推荐方法相比,所提方法在兴趣点推荐精确度上取得了较好的推荐结果,具有良好的应用前景。     

基于混合蚁群算法的异质车队低碳VRP研究

针对货运车辆在配送调度过程中产生大量碳排放的问题，建立模型将多种影响碳排放量的因素协同优化。模型中考虑了不同载重量的异质车队，两个节点之间有多条道路的柔性路径，以及车辆重量随卸货而减少的动态负载等因素，以碳排放量、行驶时间和行驶路程为优化目标，并加入了节点需求时间窗、根据速度变化划分路段、交接和卸货时间的约束。提出了一种混合蚁群算法，利用蚁群算法信息素强度更新方式保持群体记忆性，利用粒子群算法的快速收敛特性增加计算效率。通过随机数值算例的仿真优化与对比分析，验证了算法和模型的有效性。     

高温高盐油藏化学驱数值模拟技术进展

针对高温高盐油藏，胜利油田近年来先后研发了非均相体系、乳液表面活性剂体系等新型驱油体系，其驱油机理与传统化学驱油体系有明显的区别，现有商业化数值模拟软件无法有效表征，而自研数值模拟软件存在运算速度慢、难以支撑大规模矿场应用等难题。依托自主知识产权的化学驱数值模拟软件SLCHEM，在室内实验与机理研究基础上，建立了基于粘弹性颗粒孔喉通过系数的非均相复合驱数学模型以及表征乳液表面活性剂乳化增粘特征的数学模型，实现了相应的模拟功能，开展了室内试验的拟合与矿场模型应用，验证了模型的合理性和准确性；综合应用顺序全隐式快速求解算法、并行解法及交替方向解法，实现了百万级规模模型的快速计算。通过概念模型进行了计算效率测试，在网格数100×10⁴、井数116口、生产历史5a条件下，计算速度为2.9h。室内实验验证与矿场实际应用表明，与商业化软件相比，改造后的SLCHEM软件能够实现对新型驱油体系室内实验结果与矿场动态指标的准确拟合，可为化学驱方案优化与动态分析提供有效的技术支持。     

Controllability and observability of multi-agent systems with heterogeneous and switching topologies

ABSTRACT

This paper focuses on controllability and observability of multi-agent systems with heterogeneous and switching topologies, where the first- and the second-order information interaction topologies are different and switching. First, based on the controllable state set, a controllability criterion is obtained in terms of the controllability matrix corresponding to the switching sequence. Next, by virtue of the subspace sequence, two necessary and sufficient algebraic conditions are established for controllability in terms of the system matrices corresponding to all the possible topologies. Furthermore, controllability is considered from the graphic perspective. It is proved that the system is controllable if the union graph of all the possible topologies is controllable. With respect to observability, two sufficient and necessary conditions are derived by taking advantage of the system matrices and the corresponding invariant subspace, respectively. Finally, some simulation examples are worked out to illustrate the theoretical results.