基于注意力TCN的滚动轴承剩余使用寿命预测方法

针对现有的基于数据驱动的滚动轴承剩余使用寿命(RUL)预测方法仍需要大量的先验知识来提取特征、构建健康指标和设定故障阈值的现状,提出了一种基于带多头注意力机制的时间卷积网络(TCN)的RUL直接预测方法。该方法首先将原始振动信号的短时傅里叶变换(STFT)作为堆栈降噪自动编码器(SDAE)的输入,得到深度特征表示;然后将其输入到注意力TCN中进行RUL预测。最后,在PRONOSTIA的滚动轴承数据集进行验证。结果表明,本文方法的预测误差指标MAE和MAPE分别比其它四种方法平均降低了53.92%和46.13%;得分指标也比这些方法平均提高了52.98%。     

Low Hysteresis Hydrogel Induced by Spatial Confinement

Stress concentration and hysteresis often occur in polymer hydrogels under large deformation, affecting their mechanical properties, and durability. Here, a new spatial confinement gelation strategy is proposed for fabrication of hysteresis-free polymer hydrogels, and stress concentration is avoided. Experimental results and theoretical calculations confirm that the hydratability difference between salts and polymer chains leads to spatial confinement of the polymer chains by control over the ratio of bound to free water. Spatial confinement acts in place of physical cross-linking of polymer chains, which slide to dissipate energy and effectively avoid stress concentration and hysteresis, resulting in ultra-tough hydrogels with fatigue resistance. This is also a universal strategy for preparing polymer hydrogels with different monomers and salts. Taking the prepared PAM-CaCl₂ hydrogel, it displays a hysteresis of only 0.13% during load-unload cycles, even under 1000% strain. This is the lowest value among hydrogels reported to date. Along with excellent fatigue resistance, water retention, antifreeze, and water-assisted healing ability, this hydrogel shows good performance in fatigue resistant capacitive strain sensors. Moreover, a fishtail-shaped PAM-CaCl₂ hydrogel operates as a bionic muscle to drive a bionic fish at a forward speed of 16.3 cm s⁻¹, when a voltage of 0.1 V is applied.     

轴承振动测量仪校准方法研究

轴承振动测量仪是用来测量轴承振动加速度的重要计量仪器,种类繁多,应用广泛,但缺乏有效的校准检定方法。文中结合作者多年来从事振动方向校准检定的实践经验和深入的理论分析,提出了两种切实可行的校准方法,对该类仪器的校准有积极的指导意义。     

Reversible Conversion Reactions and Small First Cycle Irreversible Capacity Loss in Metal Sulfide‐Based Electrodes Enabled by Solid Electrolytes

Solid‐state batteries can potentially enable new classes of electrode materials which are unstable against liquid electrolytes. Here, SnS nanocrystals, synthesized by a wet chemical method, are used to fabricate a Li‐ion electrode, and the electrochemical properties of this electrode are examined in both solid and liquid electrolyte designs. The SnS‐based solid‐state cell delivers a capacity of 629 mAh g^?1 after 100 cycles and exhibits an unprecedentedly small irreversible capacity in the first cycle (8.2%), while the SnS‐based liquid cell shows a rapid capacity decay and large first cycle irreversible capacity (44.6%). Cyclic voltammetry (CV) experiments show significant solid electrolyte interphase (SEI) formation in the liquid cell during the first discharge while SEI formation by electrolyte reduction in the solid‐state cell appears negligible. Along with CV, X‐ray photoelectron spectroscopy and energy dispersive spectroscopy are used to investigate the differences between the solid‐state and liquid cells. The reaction chemistry of SnS in solid‐state cells is also studied in detail by ex situ X‐ray diffraction and X‐ray absorption spectroscopy. The overarching findings are that use of a solid electrolyte suppresses materials degradation and electrolyte reduction which leads to a small first cycle irreversible capacity and stable cycling.     

基于数据融合的双基阵被动定位算法的研究

为了对低空飞行目标进行定位,提出一种基于数据融合的双基阵声测被动定位方法,并对定位算法和误差进行了理论分析和数值仿真。该方法采用单基阵估计的目标方位结合双基阵阵间时间延迟的方法进行目标融合定位,充分利用了基阵间的相干性。仿真表明,该方法具有较高的定位精度。该研究成果可直接用于空中运动目标的定位,也适用于地面运动目标的定位,还可推广到多基阵的运动目标声测被动定位。     

基于方位-能量的海底声学参数估计方法研究

估计海底声学参数并应用的方法有很多种,但由于过程复杂、投入较大,大都不容易实施.文中利用建立的方位-能量估计海底参数模型,在预先给出目标距离的情况下,使用遗传算法估计海底声学参数.这使得潜艇自身的声纳既可以用于在平时训练中积累海区海底声学参数又可以在战时直接使用这些参数为作战服务.这样海底声学参数的估计与应用有机的结合为一个整体,使得整个过程简便快捷、易于实现.     

CA1040型汽车变速器设计

变速器是连接发动机和驱动轮之间的连接纽带,它的目的是让汽车在起步,转弯,爬坡加速等情况下可以选择不同的发动机牵引力。让发动机在最有利的情况下进行工作发挥最大的作用。变速器设计有不同的档位。在特定情况下还需要有一定的动力输出功能。因为发动机在低档的时候可以使汽车发挥较大的力,变速箱的低档都布置在靠近轴的后支承处。然后按从低档到高档的顺序来排布档位。这样既能保证轴的刚性又能保证装配比较容易。变速箱整体结构刚性与轴和壳体的结构有关系。一般通过控制轴的长度即控制档数,来保证变速箱有足够的刚性。本文设计研究了三轴式手动变速器,对变速器的工作原理进行了一定的研究,对变速器的档位齿轮和轴以及变速器做了详细的计算,并且进行了校核,通过查询资料对一些标准件进行了选择。本文对变速器的传动方案进行了设计并讲述了变速器中各部件材料的选择。     

气垫轴承捻股机

在６／２００和１８／２００捻股机上采用气垫轴承支承装置表明,捻股机的转速较用托轮支承可成倍地提高,且噪音低,无温升,轴面与筒体摩擦力小。支承装置寿命长,是捻股机先进的支承装置之一。     

夯实水泥土桩在加固某工程杂填土地基中的应用

结合用夯实水泥土桩来加固杂填土地基的工程实例，对用夯实水泥土桩加固地基的原理、设计计算以及施工中的有关问题进行了详细的论述；同时根据加固后的桩体及复合地基的检测结果，评价和论证了用夯实水泥土桩加固杂填土地基不仅地基承载力提高，沉降减少，而且造价低，对周围环境影响少，是值得推广应用的地基加固技术。     

一种轴承在线激光打标自动送料系统的结构设计

轴承激光打标是目前轴承生产标记的发展方向,实现轴承在线激光打标的关键是轴承生产线自动送料系统与激光打标机的匹配使用。设计了一种轴承在线激光打标自动送料系统实际应用结果表明,此系统完全可实现轴承的在线激光打标。