人工神经网络概述

近年来,随着人工神经网络在信息、自动化、医学、经济等领域的广泛应用和杰出表现,使得人工神经网络又开始得到广泛关注和重新重视。基于需求,本文对人工神经网络做了简单概述。     

二氧化碳膜分离技术

分离CO2是当前能源和环境领域最重要的课题之一,与传统方法相比,膜分离法由于具有投资少、能耗低且环境友好等优点备受关注。介绍了CO2膜分离技术的原理、传递机制、工艺流程,着重论述了国内外各种CO2膜分离技术的工作原理、研究现状,应用条件及优缺点,并对各种膜的发展方向进行了展望。     

YG20/45#钢激光焊焊缝组织与界面元素扩散研究

在无填充、不开坡口条件下,以5 k W光纤激光作为热源,研究激光扫描速度对YG20硬质合金与45#钢的焊缝组织与元素扩散的影响规律。分析了YG20/45#钢焊缝成形、组织及元素扩散。讨论了激光扫描速度对于热胀系数差异较大的异质材料焊接的焊缝成形的影响规律。研究结果表明,当被焊材料厚度为2 mm时,采用激光功率P=1.93 k W、激光扫描速度v=2.40 m/min,离焦量-8 mm时,可以获得冶金结合良好的YG20/45#钢焊接接头;随着焊接热输入的增加,硬质合金/焊缝侧界面的碳化钨晶粒粗化,裂纹倾向增加。主要分布在焊缝和硬质合金侧热影响区,降低焊接接头的性能。线扫描分析结果表明,硬质合金中的W、Co与钢中Fe发生了互相扩散,使整个接头达到了很好的冶金结合。     

Flexible and Highly Sensitive Strain Sensors Fabricated by Pencil Drawn for Wearable Monitor

Functional electrical devices have promising potentials in structural health monitoring system, human‐friendly wearable interactive system, smart robotics, and even future multifunctional intelligent room. Here, a low‐cost fabrication strategy to efficiently construct highly sensitive graphite‐based strain sensors by pencil‐trace drawn on flexible printing papers is reported. The strain sensors can be operated at only two batteries voltage of 3 V, and can be applied to variously monitoring microstructural changes and human motions with fast response/relaxation times of 110 ms, a high gauge factor (GF) of 536.6, and high stability >10 000 bending–unbending cycles. Through investigation of service behaviors of the sensors, it is found that the microcracks occur on the surface of the pencil‐trace and have a major influence on the functions of the strain sensors. These performances of the strain sensor attain and even surpass the properties of recent strain sensing devices with subtle design of materials and device architectures. The pen‐on‐paper (PoP) approach may further develop portable, environmentally friendly, and economical lab‐on‐paper applications and offer a valuable method to fabricate other multifunctional devices.     

漆包线电阻热压焊电极位移控制系统

多股漆包线与端子电阻热压焊过程中,随着焊接次数增加或焊接节拍变化,在电极上产生的热积累不同,传统的恒流控制方法难以保证接头加热的一致性.研制了一种电阻热压焊电极位移控制系统,在焊接过程中,利用光栅式位移传感器对电极位移进行实时检测,并建立模糊PID控制器实时调控焊接电流,使实际位移曲线跟踪目标位移曲线,通过控制接头热变形的方法控制接头加热的一致性.试验结果表明,与恒流控制方法相比,该方法可以实现对端子热输入的有效控制,焊接过程热输入稳定,在特定端子50次焊接试验中,焊后端子厚度误差减小了84.97％,接头的一致性有明显改善.而得益于一致性的提高,其良品率提高了13.64％.     

倒车后雾灯CMOS亮度检测及装配智能设备机构设计

针对汽车倒车后雾灯在检测装配过程中出现端子变形不良品易流出、人工主观估算亮度不准确、透气帽人工装配尺寸不能保证等问题,使用柔性检测装置检测端子偏移量是否符合要求,使用CMOS视觉系统进行灯具发光亮度检测,采用气缸自动压装透气帽.使用机械设计软件设计了一台新设备,结果表明,该设计科学合理,可以解决产品功能检测与透气帽装配的综合性问题.根据理论分析和实际验证发现:通过柔性检测装置可以检测出端子偏移量大的不良品;通过HSI机器视觉检测方法可以准确检测灯具发光亮度;采用气缸压装透气帽,位置精度可达到±0.15 mm.     

基于AMESim的组合式油压机冲盂系统仿真研究

以某型组合式油压机冲盂系统为研究对象,介绍了组合式油压机液压冲盂系统的组成和工作原理,利用AMESim软件分别建立冲盂回路中二通方向插装阀、二通压力插装阀、二通比例流量插装阀模型,并利用插装阀的样本实测曲线校正和优化仿真模型.在此基础上,建立油压机冲盂回路工作模型,完成冲盂工序油压机系统特性仿真分析,为油压机系统方案设计和驱动缸压力柔性控制提供参考.     

Wavelet Packet Analysis of Shotcrete-Rock Structures Using the Impact-Echo Method

Russian Journal of Nondestructive Testing - In this study, the contact quality of shotcrete-rock structures is studied using the impact-echo method (IE) to detect defects in shotcrete with a...     

Distensible air accumulators as a means of adiabatic underwater compressed air energy storage

In the near future, the electricity industry is likely to face historically significant changes. The onset of distributed generation, micro and smart grids will change the entire structured industry. An influx of intermittent renewable generators will make traditional grid balancing notably more difficult. The novel concept of underwater compressed air energy storage is a potentially promising solution that may be used to meet these challenges, especially during the current period of electrical infrastructure renewal and modernisation. Early results from a Lake Ontario Pilot Study point to the potential viability of the concept.     

Identifying the sources and fate of anthropogenically impacted dissolved organic matter (DOM) in urbanized rivers

Anthropogenic activities have dramatically changed the loads and compositions of dissolved organic matter (DOM) in urbanized streams. In this study, the spatial and temporal variations of DOM in the anthropogenically impacted Zhujiang River were investigated by analyzing the water samples in an upstream, urbanized area and downstream of the rivers on different days of one year. The results indicated that the levels of dissolved organic carbon (DOC) and total phosphorus (TP) were unaffected by seasonal changes, but the specific UV₂₅₄ absorbance (SUVA) values and the total nitrogen (TN) content were greater in the winter than those in the summer. Parallel factor (PARAFAC) analysis of the excitation emission matrices (EEM) revealed the presence of three anthropogenically derived components [tryptophan-like (C1) and tyrosine-like proteins (C3) and anthropogenic humic substances (C5)] in the urbanized rivers, and they had greater seasonal and spatial variability than the terrestrial and microbial humic substances (C2 and C4). Cluster analysis revealed that treated wastewater was an important source of DOM in the urbanized streams. Photodegradation experiments indicated that the DOM in the populous area of the rivers had greater photodegradation potentials than that in the downstream region or in the natural waters. Interestingly, that the anthropogenic humic substances (C5) were considerably more photoreactive than the other four PARAFAC components, which exhibited a decrease of 80% after exposure to sunlight for 0.5 d. This study suggests that the treated wastewater could be an important input to the DOM in the urbanized rivers and the naturally occurring photodegradation could help in eliminating the anthropogenic DOM during their transport.