焊剂成分对INCONEL 625丝极埋弧焊粘渣的影响

根据INCONEL 625丝极埋弧焊焊剂研制过程中的试验数据和相关资料,对几种常用成分对烧结焊剂粘渣的影响进行了简单介绍和分析。试验结果表明,容易粘渣的焊剂通常具有熔点低,氧化性高,流动性较好的特点。含有大量CaSiO_3和SiO_2的焊剂粘渣严重,为横条状和膜状粘渣。只含有SiO_2不含CaSiO_3的焊剂通常只有膜状粘渣。只含有CaSiO_3不含SiO_2的焊剂通常只有横条状粘渣。TiO_2较多时容易产生横穿焊道的条纹状粘渣,TiO_2较少在焊道两侧产生条纹状和小颗粒状粘渣。CaCO_3由于在焊接过程中分解出氧化性较强的CO_2,造成布满焊道表面的块状粘渣。CaF_2为主要成分(70%以上)的焊剂,在高温时渣壳易发生崩裂,造成布满表面的颗粒状粘渣。Al_2O_3、CaO和MgO等高温稳定的氧化物,氧化性较低,在焊接过程中不会由于过多氧化合金元素而造成粘渣,但是这些成分能够通过改变焊剂的熔点、粘度、流动性影响粘渣程度。     

道路谱测量检测技术研究综述

通过回顾近年来车辆工程的设计开发和公路行业的检测监控中,道路谱测量检测技术的理论研究和发展现状,对比分析了近年来这一领域涌现出的多种测量和检测技术的新方法。根据测试原理的不同,分为接触式测量和非接触式测量两大类来介绍。接触式道路谱测量方法的优点是测量精度高、重复性好,缺点是测量速度慢,操作复杂,测量时需要进行交通管制。非接触式测量方法优点比较明显,即测量速度快、操作简单、运行效率高,且不影响道路交通的正常运行,缺点是精度相对比较低、误差源多、价格昂贵。最后针对真实路形测量仪器的设计与开发进行了阐述,并对道路谱测量检测技术未来的发展趋势和研究前景进行了探讨。     

Extraction and pharmacological properties of bioactive compounds from longan (Dimocarpus longan Lour.) fruit — A review

Mature longan (Dimocarpus longan Lour.) fruit has a succulent, edible and white aril, which has gained popularity as an exotic fruit in temperate regions. It is prized on the international market resulting in an increased production with significant contributions to local economic development. Longan fruit contains significant amounts of bioactive compounds such as corilagin, ellagic acid and its conjugates, 4-O-methylgallic acid, flavone glycosides, glycosides of quercetin and kaempferol, ethyl gallate 1-??-O-galloyl-d-glucopyranose, grevifolin and 4-O-??-l-rhamnopyranosyl-ellagic acid. The fruit has been used in the traditional Chinese medicinal formulation, serving as an agent in relief of neural pain and swelling. The application of ultrasonic-assisted extraction or high pressure-assisted extraction greatly increases the yield from longan pericarp or seeds. In recent years, some pharmacological activities such as anti-tyrosinase, anti-glycated and anticancer activities, and memory-enhancing effects of longan aril, pericarp or seed extract have been found, implicating a significant contribution to human health. Regarding the increasing cultivation area and increasing quantity of longan fruit in the world, further utilization of this fruit is expected in an effort to use more efficiently the inherent bioactive compounds. The paper reviews the recent advances in the extraction and pharmacological activities of bioactive compounds from longan fruit. Some novel pharmacological potential of longan fruit is also discussed in this paper.     

Harmonic reducer in-situ fault diagnosis for industrial robots based on deep learning

The harmonic reducer is an essential kinetic transmission component in the industrial robots. It is easy to be fatigued and resulted in physical malfunction after a long period of operation. Therefore, an accurate in-situ fault diagnosis for the harmonic reducers in an industrial robot is especially important. This paper proposes a fault diagnosis method based on deep learning for the harmonic reducer of industrial robots via consecutive time-domain vibration signals. Considering the sampling signals from industrial robots are long, narrow, and channel-independent, this method combined a 1-dimensional convolutional neural network with matrix kernels (1-D MCNN) adaptive model. By adjusting the size of the convolution kernels, it can concentrate on the contextual feature extraction of consecutive time-domain data while retaining the ability to process the multi-channel fusion data. The proposed method is examined on a physical industrial robot platform, which has achieved a prediction accuracy of 99%. Its performance is appeared to be superior in comparison to the traditional 2-dimensional CNN, deep sparse automatic encoding network (DSAE), multilayer perceptual network (MLP), and support vector machine (SVM).

     

金属正交切削模型研究进展

鉴于切削加工巨大的经济和工艺价值,建立切削过程的理论模型,用以预测切削状态,对于优化切削条件、提高加工效率具有重要意义。国内外学者致力于该领域的研究,并在过去的几十年里建立了许多经典的正交切削模型。然而由于切削过程异常复杂,现有的切削模型并不能满足人们对切削过程精确预测的要求。因此,总结并了解已有的切削模型,对于建立更为有效的切削过程预测模型具有重要的指导和启示作用。系统回顾近几十年来在正交切削领域具有代表性的力学模型,重点介绍Merchant、Piispanen、Shaw、Lee和Shaffer、Hill、Fang、Oxley及Atkins等人的工作,阐述各自模型的主要理论、成果及其联系。最后,对正交切削模型的发展方向进行简要探讨。     

基于人的视觉特性选取图像压缩预处理方式

图像经过高比例的有损压缩后往往在细节、轮廓方面都有较大失真．为解决这一问题，在对图像进行压缩前，根据人的视觉特性和压缩方法的不同选取合适的图像处理方法，对将要压缩的图像进行预处理，将压缩时会产生较大失真的视觉敏感部分在压缩前作增强处理，进而在一定程度上实现图像压缩比的提高和图像质量的增强，以解决图像实现高压缩比与图像质量下降过大的矛盾。