半固态技术在材料连接和复合材料制备中的应用

半固态材料技术在材料成形加工领域得到了广泛的应用.综述了国内外将半固态技术作为材料连接与复合材料制备技术的研究及相关的专利,重点分析了半固态连接技术的优点并与传统工艺进行了比较,展望了这种新技术在材料科学与成形加工工程领域中的应用前景与研究方向.     

电液伺服系统的发展与应用(续)

综述了电液伺服系统的发展和研究现状,通过对电液伺服系统在力学环境模拟实验系统中的应用,分析了电液伺服系统在系统集成技术中的作用并对系统集成设计技术进行了研究。通过与电驱动系统的对比,对电液伺服系统的特性进行详细的描述,并对其发展趋势进行了分析与展望。最后介绍了我国近几年在电液伺服系统以及在基于电液伺服系统的系统集成技术的研究与应用方面取得的重要成果。     

电液伺服系统的发展与应用(续)

综述了电液伺服系统的发展和研究现状,通过对电液伺服系统在力学环境模拟实验系统中的应用,分析了电液伺服系统在系统集成技术中的作用并对系统集成设计技术进行了研究。通过与电驱动系统的对比,对电液伺服系统的特性进行详细的描述,并对其发展趋势进行了分析与展望。最后介绍了我国近几年在电液伺服系统以及在基于电液伺服系统的系统集成技术的研究与应用方面取得的重要成果。     

深海环境模拟技术在腐蚀研究上的应用现状与发展

本文论述了用环境模拟法研究钢构物在深海环境下腐蚀特性这一技术的现状与进展,包括深海腐蚀研究技术的各种主要参数及特点,重点介绍了用环境模拟法来研究钢结构在深海环境下腐蚀情况这一技术的难点,针对存在问题讨论了可行的改进方法与建议。     

人工免疫系统在智能故障诊断技术中的应用研究

在研究大量相关文献的基础上,综述了近几年来国内外对基于人工免疫系统的故障诊断技术的研究现状及人工免疫与其他智能技术融合的研究概况,并讨论了基于人工免疫系统的故障诊断技术进一步研究的方向。     

电液伺服系统的发展与应用

综述了电液伺服系统的发展和研究现状,通过对电液伺服系统在力学环境模拟实验系统中的应用,分析了电液伺服系统在系统集成技术中的作用并对系统集成设计技术进行了研究。通过与电驱动系统的对比,对电液伺服系统的特性进行详细的描述,并对其发展趋势进行了分析与展望。最后介绍了我国近几年在电液伺服系统以及在基于电液伺服系统的系统集成技术的研究与应用方面取得的重要成果。     

侯保荣院士荣获2014年度何梁何利“科学与技术进步奖”

2014年10月29日,何梁何利基金2014年度颁奖大会在北京举行,中国科学院海洋研究所侯保荣院士获得何梁何利＂科学与技术进步奖＂。侯保荣院士主要从事海洋腐蚀与防护技术研究,主持了我国近海腐蚀环境调查与研究,提出＂海洋腐蚀环境＂概念,建立了海洋腐蚀环境的理论体系。他致力于海洋钢结构浪花飞溅区防腐技术的研究与推广,在我国不同海域,     

国内外再制造技术体系及竞争力分析

为了科学评价再制造技术发展现状和竞争力,对再制造关键技术进行了分类、梳理和分析。采用文献计量学方法,重点分析了与废旧机电产品再制造相关的11项技术的国内外科技文献(SCI、CNKI)发文及专利申请情况,评价了再制造技术研究热点与趋势、研究水平和领先国家的技术发展态势。结果表明,再制造技术研究论文年均增长率达14.0%,专利年均增长率达27.8%。国外再制造技术热点主要集中在绿色清洗、无损检测与寿命评估、激光熔覆修复成形等,我国多集中在无损检测与寿命评估和修复成形两方面。我国再制造技术研究论文总体水平与发达国家还有较大差距,但部分再制造关键技术取得突破,已形成我国"尺寸修复、性能提升"的技术特色。我国在未来再制造技术体系构建中,应加强3类技术的协调发展,重点研发增材再制造技术、高效表面修复技术、智能先进涂层修复技术、绿色清洗技术以及无损检测与评估技术。     

声发射检测技术在齿轮故障诊断中的研究与应用现状

归纳了常见的齿轮故障类型,介绍了声发射技术的齿轮检测和监测原理,综述了声发射技术在齿轮故障检测中的研究与应用,包括机理研究、运行条件对声发射信号的影响以及声发射信号处理技术,着重分析了各种信号处理方法在齿轮箱故障诊断中的研究情况,并指出了声发射技术在齿轮故障诊断研究中的潜在问题和下一步研究方向,以为同行提供参考。     

欧美消失模铸造技术的现状及发展趋势——第四届(2006)Paderborn消失模研讨会侧记

根据第四届(2006)Paderborn消失模研讨会的相关内容,概述了当前欧美国家消失模技术的发展状况,并对该技术的未来发展趋势进行了展望。会议分4个主题:①消失模的国际市场;②泡沫模的设计与制造;③制造与研究;④消失模铸造研究与应用。在铝合金充型过程研究和镁合金的消失模铸造技术研究、泡沫模样材料及高表面质量模样的制备技术以及涂料透气性重要作用的研究等方面皆已取得了显著进展。     

平板件电磁成形技术的研究进展

在简述了平板件电磁成形原理的基础上,从以下4个方面综述了此技术的国内外研究进展:成形线圈设计方面,列举了平板线圈,匀压力线圈,并列线圈以及工艺校形线圈的使用;磁场力计算方面,讲述了解析法和有限元法的应用;试验研究方面,阐述了电磁成形板材成形性能研究、电磁辅助成形研究的进展;数值模拟方面,叙述了各种数值模拟方法以及有限元软件的应用。最后,指出了平板件电磁成形技术推广过程中所需攻克的技术难题。     

Finite element analysis for the semi-solid state forming of aluminium alloy considering induction heating

The major objective of this study is to establish an analytical technique in order to investigate the behavior of semi-solid material considering induction heating of the workpiece. The induction heating process is analyzed using the commercial finite element software, . The finite element program, , for the simulation of deformation in the semi-solid state is developed in the present study. The behavior of semi-solid material is described by a viscoplastic model for the solid phase and by Darcy’s law for the liquid flow. Simple compression and closed-die compression processes considering induction heating are analyzed. To validate the effectiveness of the proposed analytical technique, the results of simulation are compared with those of experiment.     

Polarisation behaviour of steel bar samples in concrete in seawater. Part 1: Experimental measurement of polarisation curves of steel in concrete

The most widely used technique for the investigation of corrosion of reinforcing steel in concrete is the linear polarisation resistance (LPR) method, which however needs to assume the Tafel slopes or the B constant for calculation of the corrosion rate. This paper aims to explore the use of a polarisation curve technique to study the polarisation behaviour and to evaluate simultaneously the corrosion rate and Tafel slopes of steel samples in concrete. As the first part of the study, this paper reviews the relevant literature, and examines the effect of the experimental technique on the measured polarisation curves of steel in concrete in seawater. In particular, differences in the results obtained by two different test procedures are examined. A comparison of the experimental polarisation curves with the theoretical curves based on charge transfer reactions is made.     

Impedance based damage detection under varying temperature and loading conditions

The impedance based damage detection technique utilizing piezoelectric materials has become a promising and attractive tool for structural health monitoring due to its high sensitivity to small local damage. However, impedance signals are also sensitive to time-varying environmental and operational conditions, and these ambient variations can often cause false-alarms. In this study, a data normalization technique using Kernel principal component analysis (KPCA) is developed to improve damage detectability under varying temperature and external loading conditions and to minimize false-alarms due to these variations. The proposed technique is used to detect bolt loosening within a metal fitting lug, which connects a composite aircraft wing to a fuselage. Model and full-scale tests are performed under realistic temperature and loading variations to validate the proposed technique. The uniqueness of this paper lies in that (1) a data normalization technique tailored for impedance based damage detection has been developed (2) multiple environmental parameters, such as temperature and static/dynamic loading are considered simultaneously for data normalization and (3) the effectiveness of the proposed technique is examined using data collected from a full-scale composite wing specimen with a complex geometry.     

双金属层状复合材料连铸工艺的研究进展

介绍用连续铸造的方法制备双金属层状复合材料的工艺特点和研究动态,提出一种双金属层状复合材料制备的新工艺--充芯连铸工艺.     

On the application of the PECLI technique (Photoelectrochemical Laser Imaging) to corrosion studies

The application of photoelectrochemistry for the micro-characterization and the study of passive films under corroding and non-corroding conditions is described. The various factors which influence the signal recorded in the PhotoElectroChemical Laser Imaging (PECLI) technique are discussed. In particular, the influence of parameters such as absorption coefficient, reflectivity, composition, structural properties and thickness of the passive film are considered. The application of the technique is demonstrated with examples of images of corroded surfaces, corroding surfaces and of a non-corroding alloy.     

Fault diagnosis of internal combustion engines using visual dot patterns of acoustic and vibration signals

An investigation of the fault diagnosis technique in internal combustion engines based on the visual dot pattern of acoustic and vibration signals is presented in this paper. Acoustic emissions and vibration signals are well known as being able to be used for monitoring the conditions of rotating machineries. Most of the conventional methods for fault diagnosis using acoustic and vibration signals are primarily based on observing the amplitude differences in the time or frequency domain. Unfortunately, the signals caused by damaged elements, such as those buried in broadband background noise or from smearing problems arising in practical applications, particularly at low revolution, are not always available. In the present study, a visual dot pattern technique is proposed to identify the acoustic emission and vibration signals for fault diagnosis in an internal combustion engine and drive axle shaft. Experiments are carried out to evaluate the proposed system for fault diagnosis under various fault conditions. The experimental results indicate that the proposed technique is effective in the fault diagnosis of an internal combustion engine and drive axle shaft.     

An improved remote sensing technique for estimating tool–chip interface temperatures in turning

This paper presents an improved remote thermocouple sensing technique for estimating cutting temperatures in a turning operation. The improved model can be used to monitor the transient cutting temperature in turning. The heat flux is estimated based on the measured remote temperature. Neither cutting forces nor heat partition factors are required for estimating the tool–chip interface temperatures. The computing time for the improved model is short. Thus the proposed remote sensing technique is suitable for industrial applications. Temperature-dependent thermal conductivity is considered in this study. Consequently, the influence of the remote sensor location on the accuracy of cutting temperature estimation is reduced. Both non-cutting tests and cutting tests are performed. Steady-state tool–chip interface temperature in cutting tests can be obtained in 5 s with the aid of Groover's model. It is found that the estimation errors are less than 8% with the improved remote sensing technique.     

激光焊接过程实时监测技术的研究现状及其发展

从监测信号和信号的处理方法两方面论述了激光焊接过程实时监测的发展现状。在激光焊接过程实时监测中常用的监测信号有声、光、热等信号，它们各具特点；信号处理和分析主要有阈值比较、时频分析、专家系统、模糊评判和人工神经网络等方法。展望了未来激光焊接过程实时监测技术的发展，提出了以传感信息融合技术为主的实时监测方式和基于高速摄影为主的实时监测方式。     

Cyclic polarization analysis of corrosion behavior of ceramic coating on 6061 Al/SiC<Subscript>p</Subscript> composite for marine applications

The study on the corrosion behavior of the composite and evaluation of surface modification technique are of importance since the addition of reinforcement particles affects the continuity of inherent oxide layer on the matrix and hence its corrosion resistance. The present study deals with the investigations of effect of ceramic coating on the corrosion behavior of 6061 Al/SiC_P (20 volume % reinforcement) composite in 3.5 M NaCl solution at high temperatures namely 30 and 40°C using potentiodynamic polarization technique and cyclic polarization plots. Aluminum coating by magnetron sputtering technique is employed on the composite and it is subjected to heat treatment at 200°C for duration of 2 h for the alumina formation. The alumina coating formed on the composite surface acts as corrosion protective coating. The potentiodynamic polarization technique is used to determine the corrosion rate of the composite specimen with and without ceramic coating in the corrosion media. The cyclic polarization technique is used to study the pitting behavior of the composite with and without ceramic coating. The microstructural analysis is carried out using scanning electron microscopy (SEM). X-RD analysis shows the amorphous nature of Alumina coating obtained on the composite. The results show that the peak aged composite is more prone to corrosion among the aged group of composites but when coated with alumina shows a vast improvement in pitting nucleation resistance even at high temperatures.