基于时频域的卷积神经网络运动想象脑电信号识别方法

针对目前运动想象脑电（EEG）信号识别率较低的问题，考虑到脑电信号蕴含着丰富的时频信息，提出一种基于时频域的卷积神经网络（CNN）运动想象脑电信号识别方法。首先，利用短时傅里叶变换（STFT）对脑电信号的相关频带进行预处理，并将多个电极的时频图组合构造出一种二维时频图；然后，针对二维时频图的时频特性，通过一维卷积的方法设计了一种新颖的CNN结构；最后，通过支持向量机（SVM）对CNN提取的特征进行分类。基于BCI数据集的实验结果表明，所提方法的平均识别率为86.5%，优于其他传统运动想象脑电信号识别方法；同时将该方法应用在智能轮椅上，验证了其有效性。     

Fabrication of hierarchical PANI@W-type barium hexaferrite composites for highly efficient microwave absorption

Hexagonal barium ferries is a promising and efficient microwave (MW) absorbing material, but the low dielectric loss and poor conductivity have limited their extensive applications. In this work, a simple tactic of coating conductive polymer PANI on hexaferrite BaCo₂Fe₁₆O₂₇ is presented, wherein the dielectric properties are customized, and more significantly, the electromagnetic loss is greatly enhanced. As displayed from structural characterizations, PANI were coated equably on the surface of hexaferrite grains by an in-situ polymerization process. The outcomes exhibit the as-prepared PANI@hexaferrite composite has remarkable electromagnetic wave absorption capacity. When the thickness is 6.0 mm, the minimal RL of ?40.4 dB was achieved at 2.9 GHz. The effective absorption bandwidth (RL < ?20 dB) of 0.65 GHz, 0.53 GHz, 0.65 GHz, 0.52 GHz, 0.46 GHz and 0.39 GHz was achieved separately when the thickness ranges from 4 to 9 mm. The highly efficient MW absorbing performance of PANI@hexaferrite composite were the consequence of multiple loss mechanisms and perfect impedance matching. It is demonstrated that the PANI@hexaferrite composite with excellent MW absorption performance is expected to be potential MW absorbers for extensive applications.     

Fabrication of direct Z-scheme FeIn2S4/Bi2WO6 hierarchical heterostructures with enhanced photocatalytic activity for tetracycline hydrochloride photodagradation

A series of direct Z-scheme FeIn₂S₄/Bi₂WO₆ hierarchical heterostructures with intimate interface contacts were synthesized by in-situ growth route and characterized by systematical analyses. All as-prepared FeIn₂S₄/Bi₂WO₆ nanocomposites showed significantly enhanced photocatalytic activity towards photodegradation for the removal of tetracycline hydrochloride (TCH) in comparison with individual FeIn₂S₄ and Bi₂WO₆. Meanwhile, the highest photocatalytic degradation activity can be achieved by modulating adding amount of FeIn₂S₄ in FeIn₂S₄/Bi₂WO₆ nanocomposites and the optimized component ratio of FeIn₂S₄ to Bi₂WO₆ is determined to be 10 wt%. The enhanced photocatalytic activity could be ascribed to efficient separation between photogenerated holes and electrons based on the construction of direct Z-scheme system. The high photocatalytic stability of resultant 10 wt% FeIn₂S₄/Bi₂WO₆ nanocomposites was revealed through six successive recycling reactions. The main intermediate generated during TCH photodegradation was explored by HPLC-MS. Besides, the direct Z-scheme photocatalytic mechanism was confirmed by band position analysis, electron spin resonance (ESR) and active species capture experiment.     

结合优化支持向量机与K-means++的工控系统入侵检测方法

针对工业控制系统传统单一检测算法模型对不同攻击类型检测率和检测速度不佳的问题，提出一种优化支持向量机和K-means++算法结合的入侵检测模型。首先利用主成分分析法（PCA）对原始数据集进行预处理，消除其相关性；其次在粒子群优化（PSO）算法的基础上加入自适应变异过程避免在训练的过程中陷入局部最优解；然后利用自适应变异粒子群优化（AMPSO）算法优化支持向量机的核函数和惩罚参数；最后利用密度中心法改进K-means算法与优化后的支持向量机组合成入侵检测模型，从而实现工业控制系统的异常检测。实验结果表明，所提方法在检测速度和对各类攻击的检测率上得到明显提升。     

A Dual Inhibitor of DYRK1A and GSK3β for β-Cell Proliferation: Aminopyrazine Derivative GNF4877

Loss of β-cell mass and function can lead to insufficient insulin levels and ultimately to hyperglycemia and diabetes mellitus. The mainstream treatment approach involves regulation of insulin levels; however, approaches intended to increase β-cell mass are less developed. Promoting β-cell proliferation with low-molecular-weight inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) offers the potential to treat diabetes with oral therapies by restoring β-cell mass, insulin content and glycemic control. GNF4877, a potent dual inhibitor of DYRK1A and glycogen synthase kinase 3β (GSK3β) was previously reported to induce primary human β-cell proliferation in vitro and in vivo. Herein, we describe the lead optimization that lead to the identification of GNF4877 from an aminopyrazine hit identified in a phenotypic high-throughput screening campaign measuring β-cell proliferation.     

Stabilizing temperature-capacitance dependence of (Sr,Pb, Bi)TiO3-Bi4Ti3O12 solutions for energy storage

(1-x)Sr_0.7Pb_0.15Bi_0.1TiO₃-xBi₄Ti₃O₁₂ ((1-x)SPBT-xBIT, x = 0-0.125) bulk ceramics were developed and calcined via the solid-state method, aimed at the application of pulsed power capacitors. The phase structures, temperature stability, hysteresis loop, and discharge properties were systematically investigated. Considering both the temperature stability and dielectric properties, 0.925SPBT-0.075BIT bulk ceramics with a capacitance variation satisfying the X7R specification were developed for pulsed power capacitors. The energy storage density was 0.252 J/cm³, and the ceramics showed high temperature stability at 80 kV/cm. The discharge current waveforms of the 0.925SPBT-0.075BIT ceramics were recorded. A high discharge power density of approximately 1.01 × 10⁸ W/kg with an 8 Ω load resistor and short discharge period of 84 ns were achieved at 50 kV/cm. The good temperature stability properties and high power density show that the 0.925SPBT-0.075BIT ceramics are well suited for pulsed power capacitors with a wide temperature range.