基于电信号特征分析的电机故障诊断技术

介绍了电机故障诊断技术平台的组成,分析了电机常见故障下电信号的特征。利用宜昌和景洪工厂两台电机进行了实际对比测试,宜昌工厂电机定子电流特征频率在49.2Hz时表现出峰值-36.08dB,在50.8Hz时表现峰值则为-37.23dB,表明电机存在转子断条故障;景洪工厂电机在转子特征频率为113.51Hz时,出现峰值-58.47dB,表明电机存在静态偏心故障。经电机现场抽芯检查,验证了电机故障快速诊断平台给出的电机健康状态评估结果,证实了基于电信号特征分析的电机故障诊断技术的准确性。     

基于Massive MIMO及频谱叠加的5G SA网络上行优化方法

大规模多输入多输出(Multiple-Input Multiple-Output, MIMO)可以有效提升5G SA网络的上行链路数据传输速率以及可靠性。针对5G SA网络上行链路速率和覆盖不均衡的情况,提出了基于大规模MIMO的分组算法,将发送信号矢量进行分组,组内采用最大似然检测,组外采用基于正交三角分解(QR分解)的干扰消除检测,并且结合5G频谱的叠加策略,在降低算法复杂度的同时,有效提升网络覆盖和速率。通过5G SA现网实测,通过MIMO降低分组数量能够提升分组检测性能,结合上行低频段频谱叠加策略能够有效提升5G SA网络上行覆盖30%,提升5G SA网络上行平均速率40%~80%,特别是弱覆盖边缘的网络速率,最高可达600%。     

Manufacturing catalyst-coated membranes by ultrasonic spray deposition for PEMFC: Identification of key parameters and their impact on PEMFC performance

This study deals with the manufacturing of catalyst-coated membranes (CCMs) for newcomers in the field of coating. Although there are many studies on electrode ink composition for improving the performance of proton-exchange membrane fuel cells (PEMFCs), there are few papers dealing with electrode coating itself. Usually, it is a know-how that often remains secret and constitutes the added value of scientific teams or the business of industrialists. In this paper, we identify and clarify the role of key parameters to improve coating quality and also to correlate coating quality with fuel cell performance via polarization curves and electrochemical active surface area measurements. We found that the coating configurations can affect the performance of lab-made CCMs in PEMFCs. After the repeatability of the performance obtained by our coating method has been proved, we show that: (i) edge effects, due to mask shadowing - cannot be neglected when the active surface area is low, (ii) a heterogeneous thickness electrode produces performance lower than a homogeneous thickness electrode, and (iii) the origin and storage of platinum on carbon powders are a very important source of variability in the obtained results.     

One-step preparation of the superhydrophobic Al alloy surface with enhanced corrosion and wear resistance

Corrosion and wear failures are bottlenecks for restricting applications and developments of Al-based functional materials. As a new lubrication technology, superhydrophobic preparation provides an effective way to settle Al alloy corrosion. The preparation methods of superhydrophobic Al alloys are mainly multistep strategies. In this study, superhydrophobic Al alloy, has been prepared by an efficient one-step electrochemical etching process. Meanwhile, its micromorphology has been observed by a scanning electron microscope. The wettability has been measured by video optical contact angle meter. The corrosion behavior has been tested by electrochemical workstation, and wear performance has been characterized by friction tester. The results show that the micro-nanoterraced concave–convex structure has been fabricated and an as-prepared surface exhibits excellent superhydrophobic behavior. Further electrochemical and tribological tests show that corrosion resistance and wear resistance have also been significantly improved. This study provides a new method to prepare wear-resistant and corrosion-resistant Al alloy for widening applications of multifunctional Al-based engineering materials.     

Stable Light-Emitting Electrochemical Cells Using Hyperbranched Polymer Electrolyte

The choice of an adequate electrolyte is a fundamental aspect in polymer light-emitting electrochemical cells (PLECs) as it provides the in situ electrochemical doping and influences the performance of these devices. In this study, a hyperbranched polymer (Hybrane DEO750 8500) blended with a Li salt is used as a novel electrolyte in state-of-the-art Super Yellow (a polyphenylenevinylene) based LECs. Due to the desirable properties of the hyperbranched polymer and the homogeneous and smooth films that it forms with the emitting polymer, PLEC with excellent electroluminescent properties are obtained using a pulsed current bias scheme. The devices are very stable, with lifetimes in excess of 2000 h with initial luminance values above 450 cd m⁻², a peak efficiency of 12.6 lm W⁻¹, and sub-minute turn-on times. The stability of the devices is also studied by measuring the photoluminescence (PL) of the semiconductor during electroluminescent operation. The findings suggest that it is possible to observe the quenching of the PL in vertically stacked devices due to the advancement of the doped fronts in the film and an immediate PL recovery when the bias is removed.     

Electrochemical Quantification of Neurotransmitters in Single Live Cell Vesicles Shows Exocytosis is Predominantly Partial

Exocytosis plays an essential role in the communication between cells in the nervous system. Understanding the regulation of neurotransmitter release during exocytosis and the amount of neurotransmitter content that is stored in vesicles is of importance, as it provides fundamental insights to understand how the brain works and how neurons elicit a certain behavior. In this minireview, we summarize recent progress in amperometric measurements for monitoring exocytosis in single cells and electrochemical cytometry measurements of vesicular neurotransmitter content in individual vesicles. Important steps have increased our understanding of the different mechanisms of exocytosis. Increasing evidence is firmly establishing that partial release is the primary mechanism of release in multiple cell types.     

激光在线测厚振动分析与精度优化

激光测厚具有安全可靠、测量精度高、测量范围大等优点,广泛应用于纸张、电池极片等薄膜类材料厚度的在线测量。带材宽幅方向扫描测厚时由于扫描架往复运动会产生机械振动,影响在线测厚精度。针对该问题,以锂离子电池极片厚度测量为例,使用双激光差动式测厚平台对电池极片和铜箔分别进行厚度测量,然后对测厚数据进行频谱分析,探究其振动规律的相似性,并基于频谱分析结果采用滑动带阻滤波方式对测厚数据进行处理,滤波后极片和铜箔的厚度极差分别降低了33.4%和73.8%,有效过滤了机械振动导致的测量误差,可满足极片和铜箔厚度测量的精度要求。     

Saliency4ASD: Challenge,dataset and tools for visual attention modeling for autism spectrum disorder

The recent studies showing that gaze features can be useful in the identification of Autism Spectrum Disorder (ASD), have opened a new domain where Visual Attention (VA) modeling could be of great help. In this sense, this paper presents a report of the Grand Challenge “Saliency4ASD: Visual attention modeling for Autism Spectrum Disorder”, organized at IEEE ICME’19, aiming at supporting the research on VA modeling towards this healthcare societal challenge. In particular, this paper describes the workflow, obtained results, and datasets and tools that were used within this activity, in order to help on the development and evaluation of two types of VA models: (1) to predict saliency maps that fit gaze behavior of people with ASD, and (2) to identify individuals with ASD from typical development.     

Corrosion behaviour of an industrial shot-peened and coated automotive spring steel AISI 9254

A high-strength low-alloy steel, AISI 9254 (54SiCr6), is widely used for suspension spring production in the automotive industry. In this work, industrially manufactured zinc phosphate coated helical springs are subjected to detailed microstructural and surface analysis for better understanding of corrosion evolution. The material’s free corrosion potential and anodic/cathodic behaviour were investigated in NaCl solutions and corrosion propagation mechanisms were studied using potentiostatic polarisation on cross-sectional and external surfaces. The bulk material is fully martensite with uniformly distributed MnS inclusions, while the spring surface has a 2–3?μm mechanically deformed region introduced by shot-peening and a thin zinc phosphate coating. The corrosion open circuit potential of bulk material and shot-peened spring surface was about –0.7V_SCE without significant difference, while phosphated surface is more noble (more positive potential). MnS inclusions, stimulating the anodic attack in the steel, influence corrosion propagation and pit morphology to a large extent that can have an impact on the spring performance.     

Q值正演模拟约束下的零偏移距VSP资料Q值估算

随着油气勘探目的层逐步走向深部,球面扩散、透射损失、环境噪声等使得VSP资料的初至子波发生改变,导致常规的Q值估算方法质量难以得到保证。为此,利用塔里木盆地托甫台地区TP327井零偏移距VSP资料,综合考虑透射损失和球面扩散的影响,提出一种Q值正演模拟约束下的零偏移距VSP资料Q值估算方法。该方法通过研究区的纵波速度、横波速度和密度建立层状地质模型,利用射线追踪的方法,用大地吸收介质模型的Q值正演模拟结果,对频谱比法和经验公式估算的初始Q值进行修正,使得Q值正演模拟结果与实际地震波的衰减记录在频谱特征上吻合,从而得到更为精确的Q模型。TP327井Q值估算结果表明,该方法与李庆忠经验公式得到的结果在浅层比较接近,但在中层和深层,两者差异较大;Q值正演模拟结果约束的子波与实际VSP资料子波的频谱比较吻合,证实用Q值正演模拟约束得到的层间Q值更为可靠。利用Q值正演模拟约束方法得到的Q模型对研究区地震资料进行反Q滤波能显著提高地震资料分辨率,有助于提高碳酸盐岩地层中缝洞的识别精度。