多级增压控制管路节流气穴噪声的试验研究

在试验研究的基础上，论述了多级节流增压模拟水泵实际运行背压具有的低噪声特性，并在此基础上对管路系统的低噪声设计提出了几点建议。     

大功率电力电子变流技术在钢铁工业中的应用

讨论了当前大功率轧机主传动采用的交流调速系统,比较了交交变频,交直交变频,IGCT/IGBT三电平PWM变频等交流调速系统的特点.还介绍了中国大功率轧机主传动交流调速系统的现状与发展.     

冲击碾压的施工工艺及质量控制措施

有关冲击碾压施工工艺及质量控制措施的探讨表明，冲击碾压在施工方面有较大的优势，不仅能提高碾压质量，还可以加快施工进度。当然，该方法也存在一些不足，只有准确把握冲击碾压的施工工艺才能既节省时间又保证施工质量，达到事半功倍的效果。     

红外线阵探测器驱动电路的低噪声设计

论文首先介绍了红外线阵探测器的系统组成和各个组成部分的功能,详细分析了红外探测系统的噪声来源,并结合实际经验,从软件到硬件电路设计,总结了降低噪声的方法,最后通过分析实验数据,得出红外线阵探测系统输出信号的噪声均方差（RMS）等于0．68mV,计算得到中波线阵探测器的NETD等于80ink,长波红外探测器的NETD等于40mK。实验数据显示通过采用本文低噪声的设计,驱动采集电路达到了比较低的噪声值,红外焦平面探测系统总体成像性能达到理想效果。     

Numerical study on flow-induced noise for a steam stop-valve using large eddy simulation

The noise induced by the fluctuant saturated steam flow under 250 °C in a stop-valve was numerically studied.The simulation was carried out using computational fluid dynamics（CFD） and ACTRAN.The acoustic field was investigated with Lighthill＇s acoustic analogy based on the properties of the flow field obtained using a large-eddy simulation that employs the LES-WALE dynamic model as the sub-grid-scale model.Firstly,the validation of mesh was well conducted,illustrating that two million elements were sufficient in this situation.Secondly,the treatment of the steam was deliberated,and conclusions indicate that when predicting the flow-induced noise of the stop-valve,the steam can be treated as incompressible gas at a low inlet velocity.Thirdly,the flow-induced noises under different inlet velocities were compared.The findings reveal it has remarkable influence on the flow-induced noises.Lastly,whether or not the heat preservation of the wall has influence on the noise was taken into account.The results show that heat preservation of the wall had little influence.     

水面舰船流噪声数值预报研究与应用

在梳理流噪声数值预报方法的基础上,采用流场大涡模拟（large eddy simulation,LES）和声学边界元（boundary element method,BEM）方法在频域内计算预报了船体流噪声谱曲线,求取了其等效声中心.LES计算时选用动力学Smagorinsky-Lilly（dynamic Smagorinsky-Lilly,DSM）亚格子应力模型,流噪声由船体壁面脉动压力和法向速度特性决定,声源节点和声节点变量传递采用一对一的守恒传递方式.结果表明：某型船在航速14 kn时,裸船体流噪声在20 Hz~2 kHz频段内总声源级为133dB;当计算有效频段扩展到20 kHz时,总声源级达143.3 dB.流噪声主要来源于兴波引起的涡量,且主要集中于100 Hz~10 kHz频段.球首尾流区和船体尾涡区对流噪声辐射量贡献明显,特别是球首尾流区,对全频段都有明显的贡献,为水面舰艇流噪声研究提供了一条新的途径.     

Evaluating Locations for Intermodal Transport Terminals

Abstract

The choice of location for an intermodal transport terminal is an important component in a regional logistics system and a paramount decision for the investor as well as the community affected. The investor needs a realistic estimation of traffic potentials and incorporated cost-estimates of a location, since it serves as an important input to the investment decision process. Policy makers need instruments and tools to analyse the effect of intermodal terminals on the surrounding environment, which also enables a comparison between several possible locations in order to ensure sustainability and long-term competitiveness. The model in this paper allows a comparative evaluation of a set of possible intermodal terminal locations based on considerations by relevant actors. Furthermore, it presents a process of retrieving data and effectively communicating results. Considerations and interests of stakeholders are incorporated into the approach by means of evaluative criteria. The approach aims at facilitating the planning process of regional logistics systems in general and the evaluation process of intermodal terminal locations in particular by considering both public and private interests focusing on economic and environmental aspects.     

广西公路环境问题分析与对策研究

文章对公路建设及营运的环境问题进行分析,提出了提高环境意识与健全制度、强化环境监督管理、制定工程与技术措施等对策建议,为相关部门防治公路环境问题提供参考。     

某大型液压挖掘机驾驶室内噪声源识别试验研究

针对某大型液压挖掘驾驶室内噪声过大现象,采用频谱分析和阶次分析等方法对该型号挖掘机驾驶室内噪声源进行试验研究。首先介绍阶次分析方法在旋转机械应用的优越性,然后比较该挖掘机在不同工况下驾驶室内噪声水平,最后根据驾驶室内噪声频谱和阶次谱特征,结合发动机、冷却风扇、柱塞泵等相关参数识别出主要噪声源,为后续噪声控制提供可靠依据。