分数阶复值神经网络的自适应投影同步（英文）

本文基于自适应混合控制研究了一类分数阶复值神经网络的投影同步.首先,在复数域上构造了一个新的分数阶微分不等式;然后,通过设计新的自适应混合控制器,利用分数阶Lyapunov引理和复变函数理论,得到了分数阶复值神经网络自适应投影同步的充分条件;最后,通过数值模拟验证了理论结果的有效性.     

Image of local energy anomaly during a heavy rainfall event

A clear and interesting image of local total energy anomaly(EA) is depicted for a heavy rainfall event in this study.Before the convection development, it exhibits a positive local EA, implying local total energy(TE) experiences heaping up to prepare for the future system development. As the convection grows, it transforms into an opposite spatial modality with negative EA dominant, which means that the local TE is consumed to feed the convection growth in the middle and lower levels. The local total EA has consistent variation regular in intensity with severe weather system evolution. By utilizing the local TE budget equation in variable density fluid, the flux divergence of energy and its components are investigated, which could account for the local TE variation better. To relax the restriction and complexity introduced by identifying sporadic and alternative positive/negative signals of EA, the method taking the absolute-value operator on energy flux divergence is used to further simplify analyses. The derived characteristic signal of absolute EA is clearer and cleaner than before.Thus, the EA could be illustrated based on the active degree of energy supply/consumption in a generalized sense whatever positive or negative anomaly should be it, which could be used easily to identify and even predict the system development for operational application. Note that, although two sets of methodologies are used to define EA herein, they play absolutely different roles in nature throughout the whole context. For example, the taking-perturbation method provides a diagnostic tool to portray a preliminary sketch and to give sufficient necessity of this research, while tendency equation of local TE illuminates more predictive sense and accounts for future local EA related to following system evolution. Therefore, the latter could be a more effective tool to routine usage.     

高效医学传感钙钛矿材料研究进展

卤化物钙钛矿材料作为一种新型半导体材料，具有优异的光电转换特性、能级结构可调、易于加工、结构和尺寸以及形貌可调、改性后优异的生物相容性等优点，在医学检测传感器中具有广阔的应用前景。本综述讨论了钙钛矿材料在生物医学传感领域的研究进展，钙钛矿医学传感器能通过光电转换、全光转换、电催化等多种物理或化学机制实现传感，具有可灵活选择的器件结构、性能指标和信号传递方式，用于人体代谢物质、神经递质、癌症相关物质和药物等医学物质的检测。钙钛矿医学传感器将为未来的医工多学科融合提供新希望，加快医工融合发展。     

Ion migration in metal halide perovskite QLEDs and its inhibition

Benefiting from the excellent properties such as high photoluminescence quantum yield (PLQY), wide gamut range, and narrow emission linewidth, as well as low-temperature processability, metal halide perovskite quantum dots (QDs) have attracted wide attention from researchers. Despite tremendous progress has been made during the past several years, the commercialization of perovskite QDs-based LEDs (PeQLEDs) is still plagued by the instability. The ion migration in halide perovskites is recognized as the key factor causing the performance degradation of PeQLEDs. In this review, the elements species of ion migration, the effects of ion migration on device performance and stability, and effective strategies to hinder/mitigate ion migration in PeQLEDs are successively discussed. Finally, the forward insights on the future research are highlighted.     

基于深度学习的透射式光学系统初始结构设计

针对传统透射式光学系统初始结构优化设计效率低、结构选取过度依赖经验等问题，提出了一种基于深度学习的透射式光学系统初始结构自动优化设计方法。通过监督训练学习公开光学镜头库中参考镜头的结构特征数据，构建基于光线追迹的无监督训练模型，提升深度神经网络(DNN)模型的泛化能力。通过训练生成的网络模型输出包含真实玻璃的光学系统的结构参数，从而实现透射式光学系统初始结构的自动优化设计。设计结果表明：利用该网络模型优化设计的光学系统初始结构在全视场、全谱段下的像面点斑半径与参考镜头接近，并且能够根据不同焦距要求分别设计出光学系统初始结构；所设计的1×10⁶组初始结构的成功率优于96.403%，表明所提网络模型具有良好的泛化能力。     

苯乙烯-间戊二烯交替共聚物环氧化研究

苯乙烯(ST)-间戊二烯(PD)通过阴离子聚合可以合成交替序列共聚物SP,基于此序列的嵌段共聚物在抗冲击高透明树脂、增韧树脂等领域有极大应用价值，同时极性化改性聚烯烃材料对提升产品相容性、耐氧化、耐热性及透明性有重要意义。本文以间氯过氧化苯甲酸(m-CPBA)为环氧化试剂对SP进行环氧化改性研究，考察了反应温度、溶剂、SP分子量及环氧化剂类型对环氧化反应的影响。通过核磁氢谱(¹H-NMR)和傅里叶红外光谱(FTIR)对环氧化SP产物(eSP)进行了结构表征。同时建立了不同环氧度eSP的定量分析方法，并通过正交实验确定了本实验所采用实验条件的最优反应条件：四氢呋喃(THF)/环己烷(CH)混合溶剂、温度343 K、C—C/m-CPBA摩尔比为1∶1.25、反应时间60 min,可以实现SP的完全环氧化。最后利用示差扫描热量仪(DSC)分析了不同环氧度eSP的玻璃化转变温度(T_g),证明环氧化改性改善产品极性的同时也能显著提升聚烯烃使用温度。     

基于亲电/亲核反应描述符的气体介质绝缘强度预测

研究分子微观参数与气体介质绝缘强度的关联，可为SF₆替代气体筛选提供方向.本文基于密度泛函理论，采用M06-2X泛函与def2系列基组，计算了73种气体分子的亲电/亲核反应描述符，包括轨道能量参数、概念密度泛函理论的参数、不同电子概率密度等值面的静电势参数等；分析了各描述符与气体介质绝缘强度的相关性，以及描述符的独立性，最终提出了绝缘强度预测模型.最低空轨道能量、正负静电势表面积、静电势平均偏差、简缩局部亲电指数最小值与绝缘强度相关性较强，且彼此间相关性较低.预测模型在电子概率密度0.0002 a.u.时精度最优，其可决系数R²为0.809,均方误差MSE为0.096.     

四氢呋喃基胺-醚类调节剂对聚共轭二烯烃微观结构影响

聚共轭二烯烃微观结构直接影响产品弹性、结晶性、耐热性、加氢、阻尼等性能。为系统探索四氢呋喃基胺-醚类调节剂(PA)对共轭二烯烃阴离子聚合微观结构的影响，本文选取N,N-二甲基四氢糠胺(DMTHFA)、N-四氢糠基吗啉(THFM)、N-四氢糠基哌啶(THFHP)和N-四氢糠基吡咯(THFP)四种高效调节剂对正丁基锂(n-BuLi)引发丁二烯(BD)、异戊二烯(IP)和间戊二烯(PD)阴离子聚合的影响，同时与工业常用的四氢呋喃(THF)进行对比。通过核磁共振氢谱(¹H-NMR)数据分析表明：(1)四氢呋喃基胺-醚类调节剂都具有微量高效调节作用，可用于生产中高支化度聚丁二烯橡胶(10%～88%)及聚异戊二烯橡胶(10%～89%),但聚间戊二烯1,2-结构含量仅能在20%～38%范围内调控摩尔比(PA/Li≤4.0);(2)在DMTHFA和THFM调节剂作用下，聚丁二烯和聚异戊二烯支化结构随着温度升高而降低，聚间戊二烯支化结构却略有增加，且DMTHFA调节剂对温度不敏感；(3)反应釜放大SEBS实验表明该类型调节剂能显著提升聚合速率，调节能力及加氢性能均优于现有工业装置醚...