以微型加速度传感器测量电感振动并评估噪音的方法

个人电脑研发过程中,经常会遇到主板区域发出“滋滋滋”的恼人的电噪音。电噪音的主要来源之一是电感的振动。当电感中有大电流或者跳变电流通过时,电感的线圈和磁芯发生振动,振动较强且频率落在20Hz~20KHz范围时,即发出人耳可听到的噪声。

896例成人嗓音声学参数的计算机采集分析

目的 通过研究获得有关嗓音医学的数据标准及各种嗓音疾病的特征性客观指标 ,建立嗓音临床检测系统 ,为临床诊断与治疗提供有效的参考标准和方法。方法 应用Dr.Speech(DSS)软件的先进技术 ,按卫生部(司 ) :“语音、语言测试和矫治行业标准”的研究要求 ,采集、分析上海地区成人 5 0 0例正常嗓音以及 396例临床常见嗓音疾病的病理性嗓音的声学样本。结果 正常人的各嗓音声学参数 :基频微扰、振幅微扰、声门噪声、频率颤动、共振峰等值均在DSS软件提供的正常范围内 ,而病理性嗓音声学参数超出该范围 ,并具有各不同的特点。结论 我国成人嗓音声学参数与欧美的相似 ,应用Dr.

Measurement system for wind turbine acoustic noise assessment based on IEC standard and Qin＇s model

A novel measurement system specially used in noise emission assessment and verification of wind turbine generator systems is presented that complies with specifications given in IEC 61400-11 to ensure the process consistency and accuracy. Theory elements of the calculation formula used for the sound power level of wind turbine have been discussed for the first time, and detailed calculation procedure of tonality and audibility integrating narrowband analysis and psychoacoustics is described. With a microphone and two PXI cards inserted into a PC, this system is designed in Qin′s model using VMIDS development system. Benefiting from the virtual instrument architecture, it′s the first time that all assessment process have been integrated into an organic whole, which gives full advantages of its efficiency, price, and facility. Mass experiments show that its assessment results accord with the ones given by MEASNET member.

股票分红与股价变动的关系研究——以沪深300板块成分股为例

本文从上市公司股票分红前后股价的变动、分红幅度对股价变动的影响、分红形式对股价变动的影响三个方面入手,进行相应的回归分析法来研究各指标对于股价变动的影响。本文研究的结论为:股票分红对于股价的提升有促进作用,分红幅度越大,股价提升的幅度越高,其中现金股利与股价的波动呈现负相关关系,股票股利与股价的波动呈现正相关关系,公司成长机会和融资行为不会对股票分红与股价变动的关系产生影响。