一种基于机器视觉的表面缺陷快速检测方法

实际生产过程中,产品表面会不同程度地留下污渍和印记,这对基于机器视觉的表面缺陷识别带来严重干扰.基于图案统计分析的识别方法速度虽快,但抗干扰能力弱,出现较高的误判率.基于深度学习的人工智能识别方法计算量巨大,速度慢,难以满足生产实际的高速要求.因此介绍一种改进SIFT算法,并给出了相关参数的设置方法和经验公式,通过实际表面缺陷的检测,对比验证了SIFT算法较强的鲁棒性和抗干扰能力,以及相关参数设置方法的正确性和可行性.实验数据表明,SIFT算法在凹陷类和斑点类缺陷的检出率上具有明显优越性,在裂纹类的误检率上也具有较大优势.特别是在有噪声图像干扰情况下,检出率比神经网络提升了20％,误检率降低了3％.     

Rational Designs for Lithium-Sulfur Batteries with Low Electrolyte/Sulfur Ratio

Lithium-sulfur batteries (LSBs) are considered a promising next-generation energy storage device owing to their high theoretical energy density. However, their overall performance is limited by several critical issues such as lithium polysulfide (PS) shuttles, low sulfur utilization, and unstable Li metal anodes. Despite recent huge progress, the electrolyte/sulfur ratio (E/S) used is usually very high (≥20 µL mg⁻¹), which greatly reduces the practical energy density of devices. To push forward LSBs from the lab to the industry, considerable attention is devoted to reducing E/S while ensuring the electrochemical performance. To date, however, few reviews have comprehensively elucidated the possible strategies to achieve that purpose. In this review, recent advances in low E/S cathodes and anodes based on the issues resulting from low E/S and the corresponding solutions are summarized. These will be beneficial for a systematic understanding of the rational design ideas and research trends of low E/S LSBs. In particular, three strategies are proposed for cathodes: preventing PS formation/aggregation to avoid inadequate dissolution, designing multifunctional macroporous networks to address incomplete infiltration, and utilizing an imprison strategy to relieve the adsorption dependence on specific surface area. Finally, the challenges and future prospects for low E/S LSBs are discussed.     

Structural health analysis on cyber physical system based on reliability

The Journal of Supercomputing - Cyber physical system (CPS) is consisting of two interdependent networks, i.e., a cyber network embedding into a physical network. Although interdependence makes the...     

基于三相幅度测量的相控阵天线快速校准方法

提出了一种基于三相幅度测量的相控阵天线快速校准方法。该方法将天线阵列进行分组,利用每种分组在三种配相下的阵面合成场幅度测量值,可解算出各个天线单元的初始幅相值。该方法仅需幅度测量,避免了相位测量误差影响单元幅相值的计算精度,而且所需幅度测量次数仅为(2N+1)次,可显著提高校准时效性。另外,利用分组思想,同时改变多个单元相位,使总辐射场的幅度变化显著,提升校准准确性。仿真结果表明:校准后相位均方根误差为2.2°,幅度均方根误差为0.2 dB。     

基于个体协同触发强化学习的多机器人行为决策方法* .txt

摘要：为了提高多机器人行为最优决策控制中强化学习的效率和收敛速度，研究了多机器人的分布式马尔科夫建模与控制策略。根据机器人有限感知能力设计了个体 协同感知触发函数，机器人个体从环境观测结果计算个体 协同触发响应概率，定义一次触发过程后开始计算联合策略，减少机器人间通讯量和计算资源。引入双学习率改进Q学习算法，并将该算法应用于机器人行为决策。仿真实验结果表明，当机器人群组数量在20左右时，本文算法的协同效率较高，单位时步比为1085 0。同时距离调节参数η对机器人协同搜索效率有影响，当η=0008时，所需的移动时步比和平均移动距离都能达到最小值。通过双学习率的引入，该算法较基于环境模型的强化学习算法具有更高的学习效率和适用性，平均性能提升35%，对于提高多机器人自主协同能力具有较高的理论意义及应用价值。 .txt     

Structure and electrical properties of Ca2+-doped (Na0.47Bi0.47Ba0.06)TiO3 lead-free piezoelectric ceramics

The lead-free piezoelectric ceramics (Na_.47Bi_.47Ba_.06)_1-xCa_xTiO₃ (x?=?0, 0.01, 0.02, 0.03, 0.05, and 0.08, abbreviated as BNBTC/0, BNBTC/1, BNBTC/2, BNBTC/3, BNBTC/5, and BNBTC/8, respectively) were obtained using the solid-state reaction method. The structure, electric conductivity, and dielectric, ferroelectric, and piezoelectric properties of the Ca²⁺-doped (Na_.47Bi_.47Ba_.06)TiO₃ ceramics were thoroughly investigated. The ceramics sintered at 1200?°C exhibit dense microstructures, having relative densities higher than 96%. The X-ray diffraction results demonstrate that all ceramics have a pure perovskite structure. The mean grain sizes of the ceramics are related to the Ca²⁺ quantity. A small quantity of Ca²⁺ ions (x?≤?0.03) improves the piezoelectric and ferroelectric properties of the samples. The dielectric behavior of the samples is sensitive to the Ca²⁺ content and electric poling. The results demonstrate that the electrical properties of the (Na_.47Bi_.47Ba_.06)TiO₃ lead-free ceramics can be well tuned by varying the Ca²⁺ quantity.     

Effects of Cooling Rate and Component on the Microstructure and Mechanical Properties of Mg–Zn–Y Alloys

The microstructure and mechanical properties of Mg–6Zn–1Y and Mg–6Zn–3Y(wt%) alloys under different cooling rates were investigated. The results show that the second dendrite arm spacing(SDAS) of Mg–6Zn–1Y and Mg–6Zn–3Y is reduced by 32 and 30% with increasing cooling rates(Rc) from 10.2 to 23 K/s, which can be predicted using a empirical model of SDAS=68 R 0:45:45cand SDAS=73 R 0c, respectively. The compressive strength of both alloys increases with increasing the cooling rate, which is attributed to the increase of volume fraction(Vf) of secondary phases under high cooling rate. The interaction of the cooling rate and component with SDAS has been theoretically analyzed using interdependence theory.     

面向过程装备工程师培养的O2O课程体系构建

过程装备与控制工程专业的人才培养方案及课程体系可以划分为线上和线下两块。线上课程侧重于新知识传授,有助于学生开阔眼界,活跃思维,启迪智慧;线下课程侧重于基本知识传授,有助于学生夯实专业基础,培养专业素养,锻炼工程技能。研究线上和线下课程的主辅关系及交互模式,形成具有鲜明流程工业装备特征的“线上+线下”一体化课程群,建立培养效果(达成度)的评价方法与持续改进机制,有利于培养掌握综合知识、善于设计计算、了解制造检验的优秀过程装备工程师。