Fault diagnosis of axial piston pumps with multi-sensor data and convolutional neural network

Axial piston pumps have wide applications in hydraulic systems for power transmission. Their condition monitoring and fault diagnosis are essential in ensuring the safety and reliability of the entire hydraulic system. Vibration and discharge pressure signals are two common signals used for the fault diagnosis of axial piston pumps because of their sensitivity to pump health conditions. However, most of the previous fault diagnosis methods only used vibration or pressure signal, and literatures related to multi-sensor data fusion for the pump fault diagnosis are limited. This paper presents an end-to-end multi-sensor data fusion method for the fault diagnosis of axial piston pumps. The vibration and pressure signals under different pump health conditions are fused into RGB images and then recognized by a convolutional neural network. Experiments were performed on an axial piston pump to confirm the effectiveness of the proposed method. Results show that the proposed multi-sensor data fusion method greatly improves the fault diagnosis of axial piston pumps in terms of accuracy and robustness and has better diagnostic performance than other existing diagnosis methods.     

基于ZigBee与GSM技术的智能家居安防系统设计

运用单片机、SIM900A模块和ZigBee无线透传模块设计了一种智能家居安防系统.结合实际需求,设计了该系统的硬件电路和应用层集中监控平台软件,实现了安装简便、工作可靠、运行成本低廉的感知单元.该智能家居安防系统可广泛应用于公司、政府、小区等区域,实用效果显著.     

逆向工程技术应用研究

随着社会的迅速发展,传统意义上的正向产品开发设计和制造模式已经不能满足企业的需要。逆向工程以产品开发周期大大缩短这一特点而在现代企业中的地位日益重要。介绍了逆向工程常用的软件,对逆向工程中常用的几种测量方法进行了对比,并用具体实例说明逆向工程的三维建模过程。     

虚拟仪器技术和数据库技术在某型两栖突击车液压系统测试软件中的应用

针对某型两栖突击车液压系统测试流程复杂、数据管理困难的特点,利用虚拟仪器技术和数据库技术等先进技术,构建了系统的数据库,完成了测试软件的设计,实现了对测试流程和相关数据的科学管理.该测试软件具有较强的移植性,在更新数据库的内容后,可直接移植到其他测试系统中.实践证明,这种方式使得用户不需掌握繁琐的测试程序编写,大大减轻了用户的负担,有很强的实践价值.     

基于RBF神经网络的底盘测功机控制算法

介绍了底盘测功机的类型并对电涡流测功机工作原理进行了说明,介绍了RBF(Radial Basis Function),神经网络的算法并分析了其控制系统模型,利用其在线整定PID(Proportion Integration Differentiation)控制技术对系统控制器进行设计,并通过MATLAB仿真给出了系统控制模式的控制效果.经试验验证,控制算法控制效果良好,完全满足底盘测功机对控制品质的要求.     

包覆层性能对输气管道纵向模态导波传播特性的影响

对带黏弹性包覆层管道中纵向模态的传播特性进行了理论分析,对纵向模态尤其是L（0,2)模态的频散和衰减特性进行了研究。建立了沥青包覆层管道的三维有限元模型,研究了激励频率、包覆层密度以及包覆层纵波衰减系数对导波传播的影响,并在带沥青包覆层钢管中进行激励和接收 L（0,2)模态的实验。结果表明,在低频范围下,随着激励频率和包覆层密度的增大,L（0,2)模态受沥青包覆层的影响也增加,其能量衰减也逐渐增大;对于带沥青包覆层的管道,其衰减频散曲线可用作模态选取的理论指导,采用低频纵向模态超声导波对带低密度包覆层管道检测时效果较好。     

电弧喷涂金属复合涂层防腐性能研究

采用电化学、耐中性盐雾、湿热、人工加速老化等测试方法,研究分析了电弧喷涂金属涂层及其复合涂层的各项防护性能,为电弧喷涂金属复合涂层体系的设计与施工应用提供了参考。     

RASAL2 acts as a tumor suppressor in cervical cancer cells

Background: This study was designed to investigate the roles of RASAL2 in cervical cancer (CC). Methods:Fifty-four CC tissues and 33 adjacent tissues were obtained from CC patients admitted to our hospital between March2012 and June 2014. Real-time polymerase chain reaction and western blotting were performed to analyze theexpression of RASAL2 mRNA and protein in these tissues, CC cell lines, and normal cervical cells. Over-expressionand silencing of RASAL2 were induced after transfection, and the migration, invasion, and proliferation of the CC celllines were examined. Results: RASAL2 mRNA and protein expressions were significantly down-regulated in CCtissues and cell lines than in adjacent tissues and normal cervical cells, respectively. While low RASAL2 expressioncorrelated with advanced stage and metastasis of CC, its over-expression significantly inhibited proliferation andmetastasis of CC cells and induced apoptosis. Under in vitro conditions, silencing of RASAL2 expression couldsignificantly increase the proliferation, invasion, and migration of CC cells. Conclusion: RASAL2 functioned as a tumor suppressor in CC, and was down-regulated in CC tissue samples and cell lines.tumor suppressor in CC, and was down-regulated in CC tissue samples and cell lines.     

机器鱼壳体三维建模及有限元分析

本文介绍了机器鱼壳体的一种建模的思路与方法,并通过ANSYSY软件对壳体进行性能分析,模拟了其在不同水深处的应力分布状况,给出壳体满足强度要求的最大水深,为探讨机器鱼的下潜深度提供了一种方法.     

美国换热器协会《电厂换热器标准》分析与讨论

介绍了美国换热器协会（HEI）《电厂换热器标准》的主要内容,对比其与GB151和TEMA换热器标准的差异,并讨论了采用该标准进行核电厂换热器设计需注意的事项。