力限振动试验技术应用与研究

首先介绍传统加速度振动试验产生过试验的主要原因;接着介绍机械阻抗特性,给出视在质量、有效质量及剩余质量的定义;然后通过对复杂二自由度方法进行理论推导,给出力限试验条件的制定方法;最后以铝板为例,建立典型力限控制试验方案,提出力限试验方法及试验步骤。从试验结果看,力限控制试验方法是缓解试件过试验的一种有效方法。     

地震作用下浮放物体的运动研究

本文从浮放物体的基本运动方程出发,导出了浮放物体受震振动的运动参数表达式,它是用仿真技术研究浮放物体地震运动的基本公式.     

基于两级拓扑优化的振动台扩展台面设计与试验验证

根据拓扑优化基本原理,利用OptiStruct进行振动台扩展台面的结构最优化设计,通过两级拓扑优化完成结构的拓扑寻优。首先利用整体级拓扑优化,找到结构的整体最佳构造。然后利用局部级拓扑优化,对局部结构进行拓扑寻优,最终完成产品的结构设计。试验结果与仿真结果对比表明,误差在5%以内,表明方法的有效性和实用性。     

Lower back pain and its association with whole-body vibration and manual materials handling among commercial drivers in Sabah

A cross-sectional study was undertaken to determine the prevalence of lower back pain (LBP) and its association with whole-body vibration (WBV) and manual materials handling (MMH). We studied 110 commercial vehicle drivers using a self-administered questionnaire and the VI-400Pro human vibration monitor. Prevalence of LBP was 66.4%. The percentage of drivers who had frequent manual handling of heavy loads was 45.5% and those who handled heavy loads in awkward postures accounted for 86.4%. Daily vibration A(8) averaged on the z axis was 0.25 (0.06) m·s^?2 and at vector sum was 0.29 (0.07) m·s^?2. Daily vibration exposures on the z axis, frequent manual handling of heavy loads and awkward posture during MMH were significantly associated with LBP. Drivers who are exposed to WBV and frequently handle heavy loads manually and with awkward postures probably have more LBP than drivers who are exposed to only one of these risk factors.     

应用在线传感器实现前置反硝化工艺生物脱氮的过程控制

为了实现前置反硝化工艺硝化反硝化反应的过程控制,系统地研究了硝化反硝化过程中DO、pH和ORP的变化规律,并考察了它们作为硝化反硝化过程控制参数的可行性.结果表明,pH值在缺氧区的变化分为下降型和上升型,从而指示系统反硝化反应进行的程度以及内循环回流量是否充足;缺氧区末端ORP值和硝酸氮浓度具有较好的相关性;好氧区第1格室的DO浓度可以指示进水氨氮负荷高低;pH值在好氧区的变化也可分为下降型和上升型,可指示系统硝化反应进行的程度、曝气量和碱度是否充足;好氧区末端ORP值与出水氨氮、硝酸氮浓度具有很好的相关性.在此基础上建立了硝化反硝化反应在线控制系统,从而实现曝气量、内循环回流量和外碳源投加量的在线控制,提高系统出水水质、降低运行费用.图7表1参8     

广州地铁工程项目环境影响评价若干问题探讨

以广州地铁六号线环境影响评价为例，结合国内外开展地铁工程项目环境影响评价的经验，对地铁项目环境影响评价的指导思想、评价重点、工程污染再分析及环境影响预测与评价等若干问题进行了探讨，以期为国内地铁工程环境影响评价工作的开展提供一些参考。     

叠加振动试验分析与应用

结合试验标准和振动控制软件,从试验应用的角度对叠加振动中的随机加随机、随机加正弦振动进行了分析和归纳,并介绍了如何从图形上快速区分叠加振动,以及在软件设置中应注意叠加振动试验中扫频和不扫频的区别。     

传感技术用于甲醛测定的研究

甲醛是一种重要的工业原料,在化工、食品、建材等方面有着广泛的应用。由于甲醛毒性大,且被怀疑具有致癌作用,目前已被认为是工厂区和室内空气中最重要的污染物之一。随着人们对空气污染的日益关注,对甲醛的准确及时检测显得更加重要。基于传感器技术而研制出的甲醛测定仪,让我们看到传感技术运用于甲醛测定领域的发展前景。本文就测定甲醛的传感器技术如电化学传感器、光化学传感器、金属氧化物传感器、电子鼻以及声表面波式传感器的一些重要应用进行了阐述。     

Designing and Implementing a Network for Sensing Water Quality and Hydrology across Mountain to Urban Transitions

Water resources are increasingly impacted by growing human populations, land use, and climate changes, and complex interactions among biophysical processes. In an effort to better understand these factors in semiarid northern Utah, United States, we created a real‐time observatory consisting of sensors deployed at aquatic and terrestrial stations to monitor water quality, water inputs, and outputs along mountain to urban gradients. The Gradients Along Mountain to Urban Transitions (GAMUT) monitoring network spans three watersheds with similar climates and streams fed by mountain winter‐derived precipitation, but that differ in urbanization level, land use, and biophysical characteristics. The aquatic monitoring stations in the GAMUT network include sensors to measure chemical (dissolved oxygen, specific conductance, pH, nitrate, and dissolved organic matter), physical (stage, temperature, and turbidity), and biological components (chlorophyll‐a and phycocyanin). We present the logistics of designing, implementing, and maintaining the network; quality assurance and control of numerous, large datasets; and data acquisition, dissemination, and visualization. Data from GAMUT reveal spatial differences in water quality due to urbanization and built infrastructure; capture rapid temporal changes in water quality due to anthropogenic activity; and identify changes in biological structure, each of which are demonstrated via case study datasets.     

关于“正弦振动试验”现行国家标准与正在修订中的新版标准的解读

正弦振动试验是试验室经常采用的振动方式,对应正弦振动试验国家标准GB／T2423．10应用非常广泛。本文介绍了该标准的用途、制修订背景等,在此基础上分析了现行正弦振动试验国家标准GB／T2423．10—2008与正在修订的6B／T2423．10—201×之间的异同之处,并指明了此标准应用中的几点注意的问题。