瓦楞纸板与EPS板材组合包装垫振动传递特性的实验研究

采用正弦扫描动态测试方法,研究双瓦楞纸板与薄EPS板材(23mm厚)组合试样在防振缓冲包装应用中的振动传递特性.测试在不同静应力下的频率响应曲线,探讨其固有频率和振动传递率与静应力之间的关系,所得数据对指导家电产品包装设计有一定实际意义.     

国外酸雨试验研究动态

酸雨对环境污染和材料的侵蚀性日趋严重,近年国外对其影响开展一系列试验研究。本文介绍其试验研究的一些情况。     

The modulation of worker behavior by the vibration signal during house hunting in swarms of the honeybee, Apis mellifera

During house hunting, honeybee, Apis melli- fera, workers perform the vibration signal, which may function in a modulatory manner to influence several aspects of nestsite selection and colony movement. We examined the role of the vibration signal in the house-hunting process of seven honeybee swarms. The signal was performed by a small proportion of the older bees, and 20% of the vibrating bees also performed waggle dances for nestsites. Compared to non-vibrating controls, vibrating bees exhibited increased rates of locomotion, were more likely to move into the interiors of the swarms, and were more likely to fly from the clusters and perform waggle dances. Recipients responded to the signal with increased locomotion and were more likely than non- vibrated controls to fly from the swarms. Because vibration signals were intermixed with waggle dances by some vibrators, and because they stimulated flight in recipients, the signals may have enhanced nestsite scouting and recruitment early in the house-hunting process. All swarms exhibited increased vibration activity within 0.5–1 h of departure. During these final periods, numerous vibrating bees wove repeatedly in and out of the clusters while signaling and motion on the swarms increased until it culminated in mass flight. The peaks of vibration activity observed at the end of the house-hunting process may therefore have activated the entire swarm for liftoff once a new nestsite had been selected. Thus, the vibration signal may help to integrate the behavior of numerous groups of workers during nestsite selection and colony relocation. Received: 17 January 2000 / Received in revised form: 5 April 2000 / Accepted: 3 May 2000     

水泥窑窑头余热锅炉热水器振动原因分析

本文对一台水泥窑窑头余热锅炉热水器的振动问题进行了分析,发现其成因为管屏内发生了脉动现象。根据锅炉运行参数与结构形式,提出了针对性的处理及预防措施,可为同类余热锅炉的运行操作与设计优化提供参考。     

Forecasting turbine problems by means of the state space framework

A forecasting system is set up to improve the diagnosis in a Condition Monitoring Programme of a critical turbine placed at an industrial plant. The system is based on a statistical model in a State Space framework, such that the local mean level of the vibration state of the equipment is estimated directly from the data, based on a continuous-time set up. This model is combined with a cost model in Conditioned Monitoring, by which the time of preventive replacement is produced when the minimum of the expected cost per unit of time is reached into the future. Such measure is a combination of the costs of failure, the costs of a preventive replacement and the probabilities of reaching the alarm levels fixed by some criteria. The system is estimated by Maximum Likelihood and thoroughly tested on the equipment. The main tests relate to statistical properties of the model residuals and a comprehensive comparison with an alternative system, namely a linear trend regression model in continuous time. The system produced a reasonable forecasting performance and sensible time of preventive replacement prediction and outperformed the alternative forecasting system.     

高架桥梁振动与结构噪声数值模拟

利用有限元软件Ansys与声学软件LMS Virtual.Lab Acoustics进行城市轨道交通高架桥梁的振动声辐射分析。首先使用Ansys对箱型梁三维模型进行瞬态动力学分析,用一列移动荷载模拟列车过桥,然后将位移响应结果导入Virtual.Lab Acoustics中,作为边界条件,计算外声场。另外通过改变桥梁参数与车辆参数,计算分析桥梁振动响应与辐射声压变化,为城市轨道交通振动与噪声的控制提供数值依据。     

优化爆破参数,减小对充填体的振动

采用机械化下向胶结充填采矿生产工艺,充填体假顶是采场生产安全的保证。为正确应用充填技术,做到安全生产,着重阐述了通过优化爆破参数,减小了爆破振动对充填体产生的危害,从而提高了井下职工在充填体下工作的安全性,并为减少矿山伤亡事故提供了经验。     

手传振动的危害及防护

综述了手传振动危害的现状及为减少振动危害开展的工作。对国内关于振动危害调查报告进行了汇总分析;研究了按行业、工种的分布情况并对常见的手持工具进行了振动测试及评价;对防振方面采取的措施进行了调查及分析;回顾及介绍了涉及手传振动的法规及标准     

水中溶解氧在受振动影响下保存条件的研究

研究的是水中溶解氧从采样到滴定分析过程中的保存条件。实验证明远距离输送样品时 ,应对溶解氧的采样瓶口进行水封处理后 ,再用胶带固定采样塞和瓶口 ,这样才能较真实的反映出所采集的原水样的准确性和可靠程度     

高层住宅水泵房噪声与振动治理

采取隔振、软联接、隔声、吸声、通风等措施,有效地控制了高层住宅水泵房的振动传递、降低了噪声,解决了高层住宅内水泵房的噪声振动影响居民生活的问题。