数控机床保护接地探析

介绍了机床接地、接零两种保护方式的工作原理。结合相关电气安装及检验规范,在保证数控机床正常工作和操作安全的前提下,对其接地、接零提出具体要求。     

可收展卫星天线用金属网技术研究进展

随着卫星通信技术的不断发展,对卫星天线的口径要求越来越大,收展工作特性要求越来越高,这使天线用金属网材料和成网技术得到了较快发展.文章介绍了国外可收展星载卫星天线的概况,分析了天线用金属网面材料、网面织构参数、成网技术的发展,以及我国金属网的研究和应用发展状况.     

热镀锌工艺在天线钢结构件表面防护上的应用

根据市场的需求，天线产品上钢结构件的表面防护要求日益严格，根据天线产品上钢结构件的特点及产业化的发展要求，对其采用热镀锌工艺，增强了钢结构件的表面防腐蚀能力，提高了工作效率，降低了成本。     

某型车载雷达天线同步举升系统仿真研究

雷达天线快速、稳定的架设和撤收是举升系统最基本的要求之一,为提高车载雷达机动性,对其举升系统的研究十分重要。通过对天线举升液压系统的分析,建立系统的数学模型,采用交叉耦合控制方式,利用AMESim和Simulink联合仿真技术对系统进行仿真研究,分析比较举升系统在有、无偏载情况下的同步特性。仿真结果表明:交叉耦合控制方式下该举升系统具有工作平稳、可靠性好以及同步精度高等优点。     

对讲机天线模具设计

对讲机天线成型一般是嵌件注射成型,外套为TPU软料,天线使用环境比较恶劣,需要有较好的耐高低温,反复弯折不损坏等性能,外观要求较高,对模具设计开发提出了较高要求。以常见的对讲机天线为例,从保证外观、产品机械性能、生产效率等多个方面来探讨模具结构,生产工艺等。总结了些经验教训,希望为模具行业的工程师提供参考。     

东方明珠天线钢桅杆腐蚀防护涂层

上海东方明珠电视塔已建成10周年。支撑天线的钢结构腐蚀涂层经过10年时间的考验,涂层完整。有达到设计要求30年的可能。文章对10年前在这方面进行的工作作一回顾。     

手机天线注射模设计

介绍了手机天线的模具设计和成形工艺,对于既要保持产品原有品质性能,又有外观要求的此类模具设计,提出了嵌件设计和浇口设置方法及与立式注塑机配套使用的特殊模具结构。经实际验证,可进行批量生产,生产效率大大提高,质量稳定可靠,符合设计要求。     

表面波天线与压电陶瓷换能器在超声导波信号接收中的效果比较

在一定条件下,超声导波检测试验中的压电陶瓷片可以作为一种表面波天线生成电磁波。将表面波天线技术应用于结构的超声导波检测,并将表面波天线接收信号与压电陶瓷片接收信号进行对比,两者完全吻合,表明表面波天线可以有效接收到超声导波检测信号。同时,对表面波天线位置对接收信号的影响进行了试验研究,发现天线处于不同位置时,接收信号在时间轴上完全吻合,且当其与试件距离不变时,接收信号无明显变化,符合表面波的传播特性。     

高速列车天线梁高效TIG焊接工艺

高速列车的天线梁制造中,部分焊缝由于质量要求高,采用了TIG焊接工艺。目前生产中主要采用手工填丝TIG焊,其生产效率低、对焊工技能要求高;而TOP-TIG焊接工艺是一种高效的自动化焊接方法。本文以天线梁环焊缝的焊接应用为背景,针对生产中需要的工艺参数进行开发,并提出了针对自动焊需要改进的点固焊方法。工艺评定结果表明,TOP-TIG焊接工艺能够满足天线梁产品的生产需要。     

组合式板坯结晶器夹紧装置设计与计算

以组合式板坯结晶器常规使用的碟簧夹紧-液压松开型夹紧装置为研究对象,详细描述了夹紧装置的结构形式、工作原理,对该装置在正常工况下的工作状态进行了分析。尤其是尽可能全面的对宽面水箱进行了受力分析,最终可以看出在结晶器整体结构不变的情况下,铸坯规格的增大对夹紧装置的夹紧力要求更大。结合设计实例对230 mm×2 000 mm规格板坯结晶器用该型夹紧装置进行了设计计算,经计算确定了在正常工况下该规格结晶器用夹紧装置的夹紧力及碟簧组合形式,进一步确定了缸筒的设计参数和设计原则。     

Field pattern characteristics of GPR antennas

Sub-surface radar has become increasingly popular for carrying out completely non-invasive integrity tests on concrete structures. Commercial systems are available with a range of antenna frequencies that may be selected for an investigation. The choice of a particular antenna frequency is often a compromise between the physical size of the antenna and the penetration and resolution capabilities provided by the antenna. However, there is an interaction between a surface contact antenna and the substrate under investigation that will alter the field pattern being transmitted that may have significant implications for interpretation of results. An experimental programme is described in which the characteristics of commercially available 900 MHz and 1 GHz antennas are compared in air and when in contact with concrete and water surfaces, together with an emulsion used in previous studies to simulate the radar properties of concrete. Results are presented showing the influence of the material being measured upon the signal divergence. These effects are considered in terms of the practical implications for field-testing using radar.     

Comparison of laboratory and simulated data for radar image interpretation

It has been shown that the output from in-house ray-tracing simulation software provides a means by which the impulse radar response of a structural system can readily be simulated. Radar simulations were undertaken of re-bar targets in a tank. A 900 MHz commercial antenna was simulated. The simulations undertaken have shown the effects that target spacing and depth have on the radar signature shapes and the results compare well with real-case survey plots. Simulation data have been used to assess the output specification from a commercial antenna, with interesting findings. It is expected that simulation will allow the interpretation of actual surveys to be more readily understood, which will in turn allow a better engineering assessment to be made of a structure under investigation.     

Reliability of flip-chip bonded RFID die using anisotropic conductive paste hybrid material

A reliability of flip-chip bonded die as a function of anisotropic conductive paste (ACP) hybrid materials, bonding conditions, and antenna pattern materials was investigated during the assembly of radio frequency identification(RFID) inlay. The optimization condition for flip-chip bonding was determined from the behavior of bonding strength. Under the optimized condition, the shear strength for the antenna printed with paste-type Ag ink was larger than that for Cu antenna. Furthermore, an identification distance was varied from the antenna materials. Comparing with the Ag antenna pattern, the as-bonded die on Cu antenna showed a larger distance of identification. However, the long-term reliability of inlay using the Cu antenna was decreased significantly as a function of aging time at room temperature because of the bended shape of Cu antenna formed during the flip-chip bonding process.     

Laboratory characterization of a GPR antenna for high-resolution testing: Radiation pattern and vertical resolution

High-resolution ground-penetrating radar (GPR) evaluations of structures are usually carried out using antennas with high nominal centre frequencies (between 1 and 2 GHz). A comprehensive characterization of such an antenna would make it possible to determine the capabilities of a system and obtain accurate data interpretations. This paper describes the experimental determination of the radiation pattern of a commercial 1.6 GHz antenna, which forms part of a comprehensive experimental characterization. Radiation patterns are closely related to spatial resolution, so the horizontal and vertical resolutions are evaluated first. The footprint of the antenna is then measured in air using simple devices at different distances. The final result is the approximate spatial radiation pattern of the emitted energy, measured in air. Finally, these measurements are also taken in sand to obtain the radiation pattern and footprint of the antenna in this medium.     

电子束焊接技术在角锥喇叭天线上的应用

研究了角锥喇叭天线的电子束焊接工艺,并与传统的氩弧焊成形工艺进行了对比.采用正背面成形的对比试验和金相分析法进一步确定了电子束扫描的有效性.解决了喇叭口径精度、单面焊双面成形等技术难点并成功应用于产品.     

Reliability of flip-chip bonded RFID die using anisotropic conductive paste hybrid material

A reliability of flip-chip bonded die as a function of anisotropic conductive paste (ACP) hybrid materials, bonding conditions, and antenna pattern materials was investigated during the assembly of radio frequency identification(RFID) inlay. The optimization condition for flip-chip bonding was determined from the behavior of bonding strength. Under the optimized condition, the shear strength for the antenna printed with paste-type Ag ink was larger than that for Cu antenna. Furthermore, an identification distance was varied from the antenna materials. Comparing with the Ag antenna pattern, the as-bonded die on Cu antenna showed a larger distance of identification. However, the long-term reliability of inlay using the Cu antenna was decreased significantly as a function of aging time at room temperature because of the bended shape of Cu antenna formed during the flip-chip bonding process.     

手机天线冲压弯曲级进模设计

介绍了手机天线冲压弯曲模的工艺及级进模结构,并对压料与回弹、凸轮弯曲作了简单的分析.     

Properties of explosion welding titanium‐steel joints with a vanadium interlayer

Special features of the manufacture of brazed waveguide slot-array antennas are discussed. The method for calculating the approximate brazing conditions is described. Samples of equipment and devices for assembling and brazing of antenna arrays are outlined.