电荷放大器的漂移问题

低频范围内的测量或可称为准静态测量。本文将就传感器和电荷放大器在准静态里的测量进行讨论,并就电荷放大器的漂移问题,时间常数及频率影响进行论述。1.传感器压电传感器是一种能量转换器,属于发电型的传感器,其输出量是电荷,也可以是电压信号。如果传感器是利用石英晶体二端     

压电式加速度传感器在振动测量系统的应用研究

压电式加速度计具有体积小、质量轻、测量范围宽等特点，在振动测量系统中得到广泛应用。分析了压电式传感器作为一种机电换能器，将振动加速度转变成为电量进行测振的具体原理；阐述了基于压电式加速度计构建振动测量系统的总体方案，整个测试系统主要由压电式加速度计、电荷放大器、动态信号分析仪组成，采集所得振动信号可以实时显示、存储、分析和处理。最后，将该系统应用于压路机实际测振进行了验证。     

《机床设计手册续编》选载——机床动态性能试验的方法和数据处理(九)

3.测力传感器 (1)测力传感器的工作原理、特点及应用 测力仪器包括三部分:测力传感器;二次仪表,包括放大器、滤波器等;记录和分析仪器。测力传感器的工作原理、特点及应用见表24。 压电式测力传感器和压电式拾振传感器,的输出为电荷量,不能直接测量,需用电压放大器或电荷放大器     

精密平衡秤的新应用--小力测量装置

对微型系统技术与毫微工艺所关心的毫牛、微牛范围内的微小力．可借助于平衡秤测量。本文介绍一种供测量范围为10毫牛～10牛的力接收器检验用的新式测力装置;这种测力装置使用了发力压电精调与测力用精密平衡秤。秤的计量特性有利于合格检验,说明了必要的改型。介绍测力装置在检验力接收器时的最初成果。     

被动红外系统用带CO2量子放大器的光电接收装置

分析了带ＣＯ２最子放大器的光电接收装置，预测放大所取ＣＯ２激光弱信号用的量子放大器的运用能将带量子放大器的光电接收装置的探测力与这种光电接收装置中运用的辐射接收器的探测力相比，提高２－５个数量级。介绍了带量子放大器的不电接收装置的结构诸元，并给出了它的主要特性。     

压电式阻抗头的测量误差分析

本文提出了压电式阻抗头的简化力学模形,用机械阻抗的方法分析,清析地表达了压电式阻抗头在机械阻抗测量中的力和运动的传递过程并导出它的力的测量误差和加速度测量误差表达式     

压电传感器的测量特性研究

本文根据W.Mahr,G.H.Gantschi在国际传感器学术会议上的发言材料和R.Kail及W.Mahr的《压电测量仪器及其应用》,就使用电荷放大器的压电传感器及其在测量应用里的特性综述如下。     

压电薄膜力传感器及其牙咬力的测量应用研究

本文介绍一种用于测量牙咬力的传感器-压电簿膜力传感器.它应用压电薄膜受到机械应力产生电极化,从而产生电荷的原理来测量牙咬力.这种压电薄膜厚度仅25μm,用它来作为传感器测量牙咬力时无咬合间隙,测量的值能反映出牙齿真实的咬力.     

阴极脉冲放大器在光点测量中的应用研究

CPT＆CDT分辨率的不同测量方法具有不同的测量精度，以脉冲静态光点测量方法测量CPT＆CDT分辨率是多种测量方法中最精确的一种，其特点是这种测量方法能在较大阴极电流变化范围内验证电子枪的设计性能和质量。脉冲静态光点测量法是利用阴极脉冲放大器输出一种周期为20ms的100ns负向视频高压脉冲，当它驱动CPT＆LCDT阴极时，阴极测试回路即可产生脉冲电流，从而使被测CPT＆CDT屏显示以50Hz为刷新频率的光点。应用于光点测试系统中的阴极脉冲放大器不仅可屏显示视觉上的稳定光点，而且能满足在宽变化阴极电流下测量光点时不烧屏的需求。阴极脉冲放大器的设计与实现是建立光点测试系统的基础，而阴极脉冲放大器在光点测量过程中的驱动方式又是能否输出高技术指标的负向视频高压脉冲的关键。     

力传感器灵敏度的动态标定

本文提出一种以单频正弦力激振标准质量块,用优选法设定电荷放大器的电荷灵敏度,实现力传感器电荷灵敏度动态标定的方法。并对力传感器的电容进行了测量,进而标定出力传感器的电压灵敏度。应用这一方法,对B&K公司生产的四个8001型阻抗头的力传感器进行了标定,结果证明,此法简便可靠,一般振动试验室几乎都可开展此工作。     

作用力作功、反作用力也作功

本文是"新功能理论"一文的第一部分,对保守力作功、保守反作用力也作功、非保守力作功、非保守反作用力也作功的分析,得出了"作用力作功、反作用力也作功"的结论.特别是对非保守力作功的研究,得到了非保守力作耗散功的同时、非保守反作用力也伴随着作耗散功,非保守力作功一般同时具有非保守性非耗散力作功、耗散力作功双重效果的结论.     

原子力显微镜的力曲线分析与转化

原子力显微镜测定的力曲线需转化为力位移曲线来应用.力位移曲线是以任意点为零点的,当研究粘附或者分子模型对比时,需要知道针尖样品间的作用力或确切的零点位置,这时需将其转化为力-距离曲线.本文首先从力曲线的测定原理得出了典型的力曲线,之后从理论上分析了力曲线、力位移曲线和力-距离曲线间的转化,从中得出了转化过程中需要的两个重要参量:灵敏度和零距离,并提出了确定方法.最后,利用MATLAB实现了曲线的自动转化.     

刮板输送机链条预紧力和紧链力计算

1引言 刮板链为一弹性体,运行时因受到拉力会产生弹性伸长,这个伸长量会使刮板链在驱动链轮分离点处松弛,甚至发生堆积而导致断链、卡链或断齿等事故的发生。为了防止这种现象,在初安装刮板链或运转一段时间后,要给其一初张力,使之产生一预加的弹性伸长。初张力（输送机静止时,封闭链条内的张力）的形成,是靠拉紧装置实现的。虽说目前使用的液压缸紧链器、液压马达紧链器和盘闸紧链器等均能准确地反映出拉紧力的大小,但对于某一特定的刮板输送机,究竟需要多大的拉紧力才满足要求,需要进行专门的计算。     

Advanced cantilevers for magnetic force microscopy and high frequency magnetic force microscopy

In order to improve the spatial resolution achieved by magnetic force microscopy (MFM) technique and its derivatives, we employ here advanced MFM tips fabricated by means of focused ion beam (FIB) milling. The magnetic coating applied on these tips is a CoCr film of 10 nm thickness. The MFM measurements on hard disk test samples reveal the achieved high resolution, and the measurement on a garnet film demonstrates the low invasiveness. High-frequency MFM (HF-MFM) is a development of the MFM technique to observe the HF stray fields emerging from magnetic recording writer poles at their operating conditions. By means of HF-MFM, magnetic recording writer poles are characterized in the frequency range 100-1,000 MHz. Up to now, all HF-MFM experiments conducted were using standard MFM cantilevers. From the HF-MFM images obtained using the advanced MFM cantilevers, it is clearly seen that the spatial resolution is considerably improved over the images obtained using standard MFM tips. However, the 10 nm thick magnetic coating of the cantilevers is found to work properly only at frequencies of up to about 500 MHz.     

Easy and direct method for calibrating atomic force microscopy lateral force measurements

We have designed and tested a new, inexpensive, easy-to-make and easy-to-use calibration standard for atomic force microscopy (AFM) lateral force measurements. This new standard simply consists of a small glass fiber of known dimensions and Young's modulus, which is fixed at one end to a substrate and which can be bent laterally with the AFM tip at the other end. This standard has equal or less error than the commonly used method of using beam mechanics to determine a cantilever's lateral force constant. It is transferable, thus providing a universal tool for comparing the calibrations of different instruments. It does not require knowledge of the cantilever dimensions and composition or its tip height. This standard also allows direct conversion of the photodiode signal to force and, thus, circumvents the requirement for a sensor response (sensitivity) measurement.     

Calibration of lateral force measurements in atomic force microscopy with a piezoresistive force sensor

We present here a method to calibrate the lateral force in the atomic force microscope. This method makes use of an accurately calibrated force sensor composed of a tipless piezoresistive cantilever and corresponding signal amplifying and processing electronics. Two ways of force loading with different loading points were compared by scanning the top and side edges of the piezoresistive cantilever. Conversion factors between the lateral force and photodiode signal using three types of atomic force microscope cantilevers with rectangular geometries (normal spring constants from 0.092 to 1.24 N/m and lateral stiffness from 10.34 to 101.06 N/m) were measured in experiments using the proposed method. When used properly, this method calibrates the conversion factors that are accurate to +/-12.4% or better. This standard has less error than the commonly used method based on the cantilever's beam mechanics. Methods such of this allow accurate and direct conversion between lateral forces and photodiode signals without any knowledge of the cantilevers and the laser measuring system.     

Development of a microlateral force sensor and its evaluation using lateral force microscopy

A microlateral force sensor (MLFS) was developed and evaluated using atomic force microscopy (AFM). The sensor was attached to a sensing table supported by a suspension system. The lateral motion of the sensing table was activated by a comb actuator. The driving voltage to the comb actuator was controlled to maintain a constant position of the sensing table by detecting the tunneling current at a detector, which consisted of two electrodes where the bias voltage was applied. An AFM was used to apply a lateral force to the sensing table of the sensor. When the probe of a cantilever was pressed against the sensing table and a raster scanning was conducted, the driving voltage of the comb actuator changed to compensate the friction force between the probe and sensing table. AFM measurements of an asperity array on the sensing table were conducted, and a lateral force microscopy image (LFM) was obtained from the change in driving voltage. The image by MLFS was very similar to the LFM image that was conventionally obtained from torsion of the cantilever. The LFM image strongly correlated with the gradient image calculated from the AFM topographic image. The force sensitivity of the MLFS was determined by comparing the LFM image obtained by using the MLFS with the tangential force derived from the gradient of the AFM image.     

Experiments and analysis of force transmission in force transducers to improve their characteristics

The influence of force transmission and transducer dimensions on the accuracy of the force measurement is studied experimentally by testing several force transducers designed and built by VTT. The results are analysed with a FEM-analysis of the transducer body. The transducers operate on the principle that the applied force creates shear forces in the transducer and these are registered with strain gauges. The testing of the transducers was performed so that the force was applied in different directions towards the transducer. In this way the inaccuracy resulting from the calibration method used can be reduced.