基于双通道注意力的轻量化PCB缺陷检测研究

印刷电路板 (printed circuit board,PCB)在实际生产过程中存在缺陷样式多种多样、缺陷小、缺陷位置难以定位的问题,而一个巨大的模型难以实现实时检测的要求,且大量的深度可分离卷积层建立的轻量级模型也不能达到足够的精度,为此提出一种基于YOLOv5s的PCB缺陷检测算法。 将原始Backbone的Conv模块跟C3模块用GhostConv替换,在Neck部分则引入了一种新的轻量级卷积技术GSConv,减轻模型大小的同时保持精度,GSConv在模型的准确性和速度之间完成了一个极好的权衡,针对许多注意力模块无法关注全局信息同时模型大的问题,提出了多尺度的轻量化双通道注意力模块(double channel depthwise attention module,DWAM),进一步提高模型精度。通过多组实验, 结果表明,改进算法所有类别的平均mAP为99.14%,且模型的GFLOPs为7.194 G,Params为7.175,原始的YOLOv5s平均mAP为96.86%,GFLOPs为6.89 G,Params为6.596,虽然Params以及GFLOPs有所增大,但是还是满足轻量网络的要求,并且精度相对于YOLOv5s提高了2.25%,且对于每个类别的缺陷识别准确率都有改善,大幅减少计算量和模型参数的同时保证了准确率,满足工业检测生产需求的同时便于移动端部署。     

彩色等离子体显示器寻址功耗等效电路模型

彩色等离子体显示器中引起的容性电流构成了寻址IC中MOS管开关电流的主体,以此为基础建立了寻址功耗等效电路模型,得到寻址功耗计算公式。典型图案寻址功耗的实验结果表明,寻址功耗和各子场图像数据在列方向上的变化率,以及相邻列之间寻址数据差在列方向上的变化率成正比,和图像信号的平均强度没有关系。寻址功耗的理论计算值和实验结果一致,寻址等效电路模型能够对不同图案的寻址功耗进行合理的解释,解决了寻址功耗检测对象不确定和检测的准确性问题。     

鄂尔多斯盆地奥陶系马家沟组规模性有效烃源岩的发现及其地质意义

尽管对于鄂尔多斯盆地奥陶系马家沟组天然气的来源问题一直都存在着不同的认识,但所有观点均不认为马家沟组自身发育TOC0.5%的规模性烃源岩。通过分析该盆地中东部奥陶系近年来大量新钻井的岩心和岩屑样品,揭示了马家沟组不同岩石类型烃源岩的有机质丰度特征,首次发现并证实马家沟组存在有机质丰度高的规模性有效烃源岩。研究结果表明:1马家沟组有效烃源岩的岩性主要为暗色薄层—厚层状含云泥岩、云质泥岩和泥云岩,其富集分布明显受沉积相的控制,马家沟组沉积期间海退期较海侵期更有利于规模性有效烃源岩的发育,层位上主要集中分布在马五上段,其次为马五中—下段、马三段和马一段;2平面上有效烃源岩围绕米脂盐洼呈双环带状分布,次级洼陷有效烃源岩呈中厚—厚层状,累计厚度大、有机质丰度高;3有效烃源岩在米脂凹陷中心和次级隆起则呈薄层状,累计厚度小、有机质丰度低;4有效烃源岩的有机碳含量变化范围为0.30%~8.45%,其生烃母质为浮游藻类和疑源类,有机质类型为腐泥型或偏腐泥混合型。结论认为:该盆地奥陶系有效烃源岩普遍处于过成熟阶段,以产干气为主,生气量大,是马家沟组天然气的主要贡献者。     

Precisely Controlled Hydration Water for Performance Improvement of Organic–Inorganic Perovskite Solar Cells

Recently, intensive studies on the role of water molecule in the formation of organic–inorganic perovskite film have been reported. However, not only the contradictive phenomena but also the complex processing technique has hindered the widespread use of water molecule in perovskite preparation. Here the hydration water is introduced into the precursors instead of water. By precisely controlling the content of hydration water, a smoother and more uniform perovskite film is obtained through a simple one‐step spin coating method. The improvement of perovskite film quality leads to highly efficient planar perovskite solar cells. Summing up the device studies and the investigation of morphology, crystallization, and optical properties, the impact of water molecule in the formation of perovskite crystal and consequences of device performance is understood. Due to its universal adaptability and simplified process, precise control of hydration water is therefore of great utility to high quality perovskite films fabrication and large‐scale production of this upcoming photovoltaic technology.     

Au‐Decorated Cracked Carbon Tube Arrays as Binder‐Free Catalytic Cathode Enabling Guided Li2O2 Inner Growth for High‐Performance Li‐O2 Batteries

Owing to their extremely high energy density, Li‐O₂ batteries have attained increasing attention in recent studies. However, deposition of the discharge product, insulating Li₂O₂, is known to seriously limit the electrochemical performance of Li‐O₂ batteries. While extensive studies have focused on relieving electrode deactivation by controlling Li₂O₂ growth, no permanent or effective mechanism is delivered. Here, a unique design comprising a catalytic cathode constructed by cracked carbon submicron tube (CST) arrays decorated with Au nanoparticles on inner walls is proposed. The introduction of Au nanoparticles not only improves electrode conductivity but also provides catalytic sites, guiding conformal growth of thin‐layered Li₂O₂ inside the cracked CST. Density functional theory calculations support that Au decoration on CST favors the conformal growth of Li₂O₂ on inner tubular walls. This growth behavior of Li₂O₂ renders easy decomposition of Li₂O₂, prevents carbon tube electrode from full, rapid deactivation, and preserves the free space for reactants transport. Li‐O₂ cells with Au@CST exhibit good rate capability (1208 mAh g^–1 at a high current density of 1000 mA g^–1) and long cycle life (112 cycles at a current density of 400 mA g^–1 with a limited capacity of 500 mAh g^–1).     

Light and Strong SiC Networks

The directional freezing of microfiber suspensions is used to assemble highly porous (porosities ranging between 92% and 98%) SiC networks. These networks exhibit a unique hierarchical architecture in which thin layers with honeycomb‐like structure and internal strut length in the order of 1–10 μm in size are aligned with an interlayer spacing ranging between 15 and 50 μm. The resulting structures exhibit strengths (up to 3 MPa) and stiffness (up to 0.3 GPa) that are higher than aerogels of similar density and comparable to other ceramic microlattices fabricated by vapor deposition. Furthermore, this wet processing technique allows the fabrication of large‐size samples that are stable at high temperature, with acoustic impedance that can be manipulated over one order of magnitude (0.03–0.3 MRayl), electrically conductive and with very low thermal conductivity. The approach can be extended to other ceramic materials and opens new opportunities for the fabrication of ultralight structures with unique mechanical and functional properties in practical dimensions.     

利用地层压力系数分析黄河口凹陷中央隆起带新近系油气输导体系

油气输导体系沟通烃源岩和圈闭,在油气成藏过程中具有关键作用。以黄河口凹陷中央隆起带新近系为研究目的层,基于层序地层发育特征,分析研究区4个油田的实测地层压力系数,进而探讨不同地层压力系数条件下的油气输导体系。研究结果表明,正常地层压力条件下黄河口凹陷中央隆起带新近系发育低地层压力系数—高渗透性储层油气输导体系、高地层压力系数—中等渗透性储层油气输导体系和中等地层压力系数—高渗透性储层油气输导体系。黄河口凹陷中央隆起带的凹陷区—缓坡带的馆陶组与明下段V油组、缓坡带—凸起区的明下段Ⅲ油组以低地层压力系数—高渗透性储层油气输导体系为主,凹陷区—缓坡带的明下段Ⅲ油组以高地层压力系数—中等渗透性储层油气输导体系为主,凸起区以中等地层压力系数—高渗透性储层油气输导体系为主。     

Synthesis, characterization and hydrolytic degradation study of polyetheresteramide copolymers based on ε-caprolactone, 6-aminocaproic acid, and poly(ethylene glycol)

In this paper, a new kind of biodegradable aliphatic polyetheresteramide copolymers (PEEA) based on -caprolactone, 6-aminocaproic acid, and poly(ethylene glycol) (PEG) were synthesized by melt polymerization method. The obtained copolymers were characterized by ¹H-NMR. The thermal properties of PEEA copolymers were studied by DSC and TGA/DTA under nitrogen atmosphere. The water absorption and hydrolytic degradation behavior was also studied in detail. With the increase in PEG content or the decrease in caprolactone content, the water absorption of the copolymers increased accordingly. For the hydrolytic degradation behavior, with the increase in PEG content or caprolactone content, the degradation rate increased then.     

Autonomously replicating plasmid transforms Sorangium cellulosum So ce90 and induces expression of green fluorescent protein

A recombinant plasmid, pRP-GFP, harboring the green fluorescent protein (GFP) gene from the broad-host-range mobilizable plasmid pRK415 of the RK2 family was constructed and transferred by conjugation from Escherichia coli S17-1 to Sorangium cellulosum So ce90. The results of Southern blot analysis showed that the plasmid replicated autonomously without being integrated into the chromosome of the bacterium. In pRP-GFP, gfp was driven by a So ce90 DNA fragment called EpoPro, which is an 890-bp DNA segment spanning from -890 to -1 relative to the start codon (GTG) of epoA, a gene that encodes EPOS A, which is presumed to be involved in the initiation of epothilone biosynthesis. The GFP in the transformed S. cellulosum So ce90 was detected by fluorescence microscopy, which suggests that the EpoPro fragment had the function of promoter. Because the green fluorescent bacilli could be directly observed by fluorescence microscopy, the stable expression of GFP was rapid and convenient for conjugation screening in addition to the antibiotic resistance genes within the constructed plasmid. This is the first report on an exogenous plasmid that can be stably maintained as an extrachromosomal element in S. cellulosum.     

Frequency-domain Analysis of ECG Signal

A new simple approach to effectively detect QRS-T complexes in ECG curve is described,so as to easily get the P-wave（when AF does not happen）or the f-wave（when AF happens）．By means of signal processing techniques such as the power spectrum function,the auto-correlation function and cross-correlation function,two kinds of ECG signal when AF does or does not happen were suc cessively analyzed,showing the evident differences between them．