PCB 缺陷检测深度学习算法的精度改进

本文以YOLOv5目标检测算法为基础算法,针对PCB缺陷检测进行了提高精度的改进。首先通过实验选取了合适的数据增强方法。针对PCB缺陷尺寸小的问题,在原有的3个检测头基础上增加了P₂检测头。设计全新的PANet多特征融合结构,实现高效的双向跨尺度连接和加权特征层融合。针对PCB背景复杂的问题,引入了CBAM注意力模块以增强图像信息。引入了Transformer模块来增强算法,以提高捕捉不同位置的PCB缺陷信息的能力。最终通过这些改进,在检测速度FPS仅下降7.2的情况下,检测算法的mAP精度提高了11.3%。     

基于粒子群算法的阵列天线波束赋形研究

波束赋形可以得到雷达系统所希望的理想辐射波束,然而传统分析方法存在理论分析繁琐、计算量较大的缺点,不利于在实际的工程应用中得到推广和使用。文章提出了一种基于粒子群算法对波束赋形的研究方法,具有代码简单、计算快速准确等优势。根据直线阵列的基本理论建立基本模型及方向图波瓣评估函数,最后得出两个案例的分析结果。计算结果验证了该方法的可行性和高效性,利于在实际工程中得到应用。     

基于蝴蝶优化的配电线路双层迭代降损方法研究

为解决10 kV长配电线路损耗大、电压质量差及降损设备年投资回报率低等问题,提出一种结合蝴蝶优化的配电线路双层迭代降损增效方法。首先,考虑线路负荷三相不平衡,应用电力系统仿真软件OpenDSS建立目标配电线路分相潮流仿真模型。其次,增加10 kV线路无功补偿装置容量与位置以及调压器分接头挡位与位置为控制变量,建立以考虑全寿命周期成本(life cycle cost, LCC)的年投资回报率最大为目标的外层规划模型,以年有功损耗及年平均电压偏移量最小的多目标为内层运行模型。然后,利用蝴蝶算法通过Python调用OpenDSS潮流计算模型仿真,得到潮流结果和理论线损并求解降损模型。最后,以某供电公司线路为算例进行验证,结果表明该方法能为线路降损提供实用的实施方案。     

Progress of Phosphate-based Polyanion Cathodes for Aqueous Rechargeable Zinc Batteries

Aqueous rechargeable zinc batteries (ARZBs) are recently prevailing devices that utilize the abundant Zn resources and the merits of aqueous electrolytes to become a competitive alternative for large-scale energy storage. Benefiting from the unique inductive effect and flexible structure, the past five years have experienced a diversiform of phosphate-based polyanion materials that are used as cathodes in ARZBs. In this review, the most recent advances in the Zn²⁺ storage mechanisms and electrolyte optimization of the phosphate-based cathodes of ARZBs, which mainly focus on vanadium/iron-based phosphates and their derivatives are presented. Furthermore, in addition to significant progress on polyanion phosphate-based cathode materials, the design strategies both for electrode materials and compatible electrolytes are also elaborated to improve the energy density and extend the cycling life of aqueous Zn/polyanion batteries.     

Himawari-8气溶胶变分同化对PM2.5污染模拟的改进

利用地球静止轨道卫星Himawari-8 气溶胶光学厚度 (AOD) 产品能够估算空间覆盖范围广、时间分辨率高的 近地表 PM2.5 浓度。基于三维变分同化系统将AOD估算得到的 PM2.5 资料同化进入WRF-Chem大气化学模式中, 通过 控制实验与同化实验的对比与分析, 探讨了AOD估算得到的PM2.5资料同化对 PM2.5 污染模拟的改进作用。实验结果 表明： (1) AOD估算得到的 PM2.5 资料同化能够改进 PM2.5 污染模拟效果;(2) PM2.5 污染模拟改进效果存在时空差异。 此外, 与其他研究中使用AOD观测算子直接同化AOD的方法相比, 该方法的操作更加简单。     

Doped/Undoped A1-A2 Typed Copolymers as ETLs for Highly Efficient Organic Solar Cells

The electron transport layer (ETL) is a critical component in achieving high device performance and stability in organic solar cells. Conjugated polyelectrolytes (CPEs) have become an attractive alternative due to film-forming properties and ease of preparation. However, p-type CPEs generally exhibit poor charge mobility and conductivity, incorporation of electron-withdrawing units forming alternated D-A conjugated backbone can make up for these deficiencies. Herein, the ratio of electron withdrawing moieties are further increased and two poly(A1-alt-A2) typed PIIDNDI-Br and PDPPNDI-Br based on the combination of naphthalene diimide (NDI) with isoindigo (IID) or diketopyrrolopyrrole (DPP) via direct arylation polycondensation are synthesized. These CPEs possess excellent alcohol solubility, a suitable lowest unocuppied molecular orbital energy level, and work function tunability. Surprisingly, the incorporation of IID and DPP units generate distinct self-doping behaviors, which are confirmed by UV–vis absorption and ESR spectra. However, no matter doped or undoped, both CPEs present better charge-transporting properties and conductivity when utilized as ETLs. The PIIDNDI-Br and PDPPNDI-Br display good universal compatibility with the blend of PM6:Y6 and PM6:L8-BO, and PCEs of 18.32% and 18.36% are obtained, respectively, which also present excellent storage stability. In short, the combination of two different acceptors demonstrates an efficient strategy to design highly efficient ETLs for high performance photovoltaic devices.     

Surface Growth of Boron Nitride Nanotubes through Boron Source Design

Boron nitride nanotubes (BNNTs) are promising materials due to their unique physical and chemical properties. Fabrication technologies based on gas-phase reactions reduce the control and collection efficiency of BNNTs due to reactant and product dispersion within the reaction vessel. A surface growth method that allows for controllable growth of BNNTs in certain regions using a preburied boron source is introduced. This work leverages the high solubility of boron in metals to create a boronized layer on the surface which serves as the boron source to confine the growth of BNNTs. Dense and uniform BNNTs are obtained after loading catalysts onto the boronized substrate and annealing under ammonia. Confirmatory experiments demonstrate that the boride layer provides boron for BNNTs growth. Furthermore, the patterned growth of BNNTs is realized by patterning the boronizing region, demonstrating the controllability of this method. In addition, the Ni substrate with BNNTs growth exhibits better performance in corrosion resistance and thermal conductivity than pure Ni. This study introduces an alternative strategy for the surface growth of BNNTs based on boron source design, which offers new possibilities for the controllable preparation of BNNTs for various applications.     

Recent Development of Jumping Motions Based on Soft Actuators

Drawing inspiration from the jumping motions of living creatures in nature, jumping robots have emerged as a promising research field over the past few decades due to great application potential in interstellar exploration, military reconnaissance, and life rescue missions. Early reviews mainly focused on jumping robots made of lightweight and rigid materials with mechanical components, concentrating on jumping control and stability. Herein, attention is paid to the jumping mechanisms of soft actuators assembled from various soft smarting materials and powered by different stimulus sources. The challenges and prospects of soft jumping actuators are also discussed. It is hoped that this review will contribute to the further development of soft jumping actuators and broaden their practical applications.     

Construction of VS2/VOx Heterostructure via Hydrolysis-Oxidation Coupling Reaction with Superior Sodium Storage Properties

Heterostructure engineering is one of the most promising modification strategies for reinforcing Na⁺ storage of transition metal sulfides. Herein, based on the spontaneous hydrolysis-oxidation coupling reaction of transition metal sulfides in aqueous media, a VO_x layer is induced and formed on the surface of VS₂, realizing tight combination of VS₂ and VO_x at the nanoscale and constructing homologous VS₂/VO_x heterostructure. Benefiting from the built-in electric field at the heterointerfaces, high chemical stability of VO_x, and high electrical conductivity of VS₂, the obtained VS₂/VO_x electrode exhibits superior cycling stability and rate properties. In particular, the VS₂/VO_x anode shows a high capacity of 878.2 mAh g⁻¹ after 200 cycles at 0.2 A g⁻¹. It also exhibits long cycling life (721.6 mAh g⁻¹ capacity retained after 1000 cycles at 2 A g⁻¹) and ultrahigh rate property (up to 654.8 mAh g⁻¹ at 10 A g⁻¹). Density functional theory calculations show that the formation of heterostructures reduces the activation energy for Na⁺ migration and increases the electrical conductivity of the material, which accelerates the ion/electron transfer and improves the reaction kinetics of the VS₂/VO_x electrode.     

An Apoptotic Body-based Vehicle with Navigation for Photothermal-Immunotherapy by Precise Delivery and Tumor Microenvironment Regulation

Tumor precision therapy and preventing tumor recurrence and metastasis are the main challenges to tumor eradication. Herein, an apoptotic body-based vehicle with imaging navigation is developed for precise tumor delivery and photothermal-immunotherapy by IR820-conjugated apoptotic body loaded with R848 nanoparticles. The apoptotic body serves as ammunition stores as well as vehicle drive engines, while IR820 acts as a fluorescence imaging navigation and photothermal controlling system. The apoptotic body vehicle can deliver the ammunition to tumor and achieve deep penetration by macrophage-hitchhiking. Fluorescence imaging navigation opens a control window for photothermal treatment, followed by photothermal triggering of in situ vaccine formation. Further, CD47 antibody loaded hydrogel strengthens innate and adaptive immunity, simultaneously the polarization of macrophages regulates the immunosuppressive microenvironment to further promote the combined antitumor immunotherapy. With breast tumor (4T1)-bearing mice model, the apoptotic body vehicle performs excellent therapeutic efficacy for primary tumor, distant tumor, tumor metastasis, and recurrence prevention.