Palladium‐Catalyzed Direct Cross‐Coupling of Carboranyllithium with (Hetero)Aryl Halides

A palladium‐catalyzed direct C‐arylation reaction of readily available cage carboranyllithium reagents with aryl halides has been developed for the first time. This method is applicable to a wide range of aryl halide substrates including aryl iodides, aryl bromides, and heteroaromatic halides.     

Identification and releasing characteristics of β-cyclodextrin–phenylethanoid glycosides inclusion complex

β-Cyclodextrin–phenylethanoid glycosides inclusion complex was prepared and its releasing characteristic was investigated in this study. The results, obtained from Fourier-transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction, indicated that phenylethanoid glycosides (PG) were able to form an inclusion complex with β-cyclodextrin (β-CD). This complex exhibited different spectroscopic features, thermal stability and crystalline structure from PG. Molecular simulation results showed the benzene rings of PG incorporating into the hydrophobic cavity of β-CD during the complex formation. Furthermore, the releasing rate of the included PG in the inclusion complex was positively correlated with temperature and it was slightly higher in 0.5 % HCl solution than in water. These results suggested that the complexation technique using β-CD was a promising strategy for increasing the applications of PG in food and healthcare industries.     

Trackable Supramolecular Fusion: Cage to Cage Transformation of Tetraphenylethylene‐Based Metalloassemblies

Herein, the trackable supramolecular transformation of a two‐component molecular cage to a three‐component cage through supramolecular fusion with another two‐component molecular square is described. The use of tetraphenylethene (TPE), a chromophore with aggregation‐induced emission (AIE) character, as a component for the molecular cages enables facile fluorescence monitoring of the transformation process: while both cages exhibit fluorescence emission via the restriction of intramolecular motion of the TPE motif, the interactions between TPE and 4,4′‐bipyridine introduced in the supramolecular fusion process result in partial fluorescence quenching and shifts in the emission maximum. This study provides a simple and efficient approach towards complex supramolecular cages with emergent functions and demonstrates that AIE features could provide unique opportunities for the characterization of complex, dynamic supramolecular transformation processes.     

面向5G的大规模MIMO天线的波束规划及天线选型探讨

大规模MIMO天线技术作为5G技术的关键,在解决超高容量和多用户连接的问题上极具优势。天线的实际增益效果与多波束的管理和天线的选型紧密相关。基于此,本文先行阐述了大规模MIMO天线的波束形成技术,提出了不同场景下的多套波束规划方案,并进一步地对不同覆盖场景给出天线选型建议,为5G的网络设计与建设提供切实可行的参考依据。     

Dynamic mechanism of epileptic seizures generation and propagation after ischemic stroke

Nonlinear Dynamics - Epilepsy is the second largest neurological disease which seriously threatens human life and health. The one important reason of inducing epileptic seizures is ischemic stroke...     

二维光编解码链路监测系统环境温度补偿算法研究

为解决二维光编解码接入网链路监测系统中反射光脉冲信号随温度变化的问题,提出了一种温度补偿算法。动态分析了检索脉冲光信号与二维光编码器互作用过程,推导得出编码光纤光栅中心波长温度漂移与反射光信号波形表达式,确定了补偿系数,给出其随温度变化的动态关系。搭建了实验系统,获得编码光纤光栅中心波长随温度变化系数为0.00932 nm/℃,通过温度补偿的系统可在-30~80℃环境正常工作,实现光纤链路状态精准判决。     

Fast Potassium Storage in Hierarchical Ca0.5Ti2(PO4)3@C Microspheres Enabling High‐Performance Potassium‐Ion Capacitors

Hybrid potassium‐ion capacitors (KICs) show great promise for large‐scale storage on the power grid because of cost advantages, the weaker Lewis acidity of K⁺ and low redox potential of K⁺/K. However, a huge challenge remains for designing high‐performance K⁺ storage materials since K⁺ ions are heavier and larger than Li⁺ and Na⁺. Herein, the synthesis of hierarchical Ca_0.5Ti₂(PO₄)₃@C microspheres by use of the electrospraying method is reported. Benefiting from the rich vacancies in the crystal structure and rational nanostructural design, the hybrid Ca_0.5Ti₂(PO₄)₃@C electrode delivers a high reversible capacity (239 mA h g^?1) and superior rate performance (63 mA h g^?1 at 5 A g^?1). Moreover, the KIC employing a Ca_0.5Ti₂(PO₄)₃@C anode and activated carbon cathode, affords a high energy/power density (80 W h kg^?1 and 5144 W kg^?1) in a potential window of 1.0–4.0 V, as well as a long lifespan of over 4000 cycles. In addition, in situ X‐ray diffraction is used to unravel the structural transition in Ca_0.5Ti₂(PO₄)₃, suggesting a two‐phase transition above 0.5 V during the initial discharge and solid solution processes during the subsequent K⁺ insertion/extraction. The present study demonstrates a low‐cost potassium‐based energy storage device with high energy/power densities and a long lifespan.     

布尔矩阵的指标格(英文)

本文介绍了布尔矩阵的指标格,并讨论了它的性质,得到了从布尔矩阵指标格到一个给定完备格的一个序嵌入映射存在的条件,回答了在什么条件下布尔矩阵的指标格是完全分配格的问题。     

面向多目标透镜的连通域标记检测算法

文中提出了一种适合FPGA实现的多目标连通域标记算法。该算法通过初次扫描时在图像的边框处做特殊的标记值,提取出环形具有内外双层轮廓的目标内部区域,进而将紧挨在一起的目标分离开以实现多目标的检测。该方案采用单次逐像素扫描的方法,对图像进行一次逐像素扫描即可完成连通域的标记和等价表的整理。实验结果表明,对一幅大小为M×N的图像,在不计算等价表递归时间的情况下,经过M×N×2个时钟周期后可识别出多个目标,且得到了每个目标对应区域的面积和外接矩形等参数。     

改进混沌粒子群算法的四旋翼PID姿态控制

PID控制器在四旋翼飞行控制系统中比较常见,其核心问题之一就是PID参数的整定.常见的调参方法有模糊控制、神经网络及手动调参.针对四旋翼飞行器的PID控制器参数整定困难,提出一种基于混沌粒子群算法的PID参数整定方法:首先,利用粒子群算法的收敛速度较快及混沌序列的遍历性、随机性以及对初值的敏感性等特性,使得调节PID参...