T型触探不同截面形状探头变形和强度分析

T型触探仪探头轴长比越小,表面粗糙度对测试结果的影响越小,但探头的变形会增加,强度会减小。针对T型触探探头与静力触探的丝扣式和锥槽式这两种结合方式,该文取一半探头进行分析,假定探头为悬壁梁,分别分析了探头挠度、探头底部中点强度随探头轴长比的变化情况。结果显示,矩形截面最优,菱形截面最差。随着轴长比的减小,探头端部的挠度迅速增加,探头强度逐渐降低。锥槽的存在对探头挠度和强度的影响很小。采用轴长比为0.5的探头,能够满足探头变形和强度的要求。     

小型超声波探头加工图

一、探头加工说明1、本图册包括探头插件(1—6),横波、表面波探头,纵波探头共三部分。2、探头插件由(1—6)零件图组成。3、横波、表面波探头由探头外壳及透声楔(7—12)零件图组成。4、纵波探头由探头手柄及透声楔(13—17)零件图组成。5、机械加工时,均按零件图要求,并需分别按组装图考虑公差配合尺寸。二、探头外形照片     

泰克公司推出三款新无源探头

泰克公司最近宣布,为TPP系列无源电压探头系列新增两款新产品——新TPP0850和TPP0502探头,同时推出P5100A高压探头。新的TPP系列探头具有业内最低的探头负载,是需要开发能效更高的电源和功率半导体器件的工程师的理想选择。     

开口同轴探头去嵌入技术的研究

开口同轴探头测量技术,由于可实现非破坏性测试,一直是众多科学家及工程技术人员关注的焦点。但对于同轴探头的误差分析,研究不够深入。相位补偿技术是最常用的同轴探头去嵌入技术,该技术假设同轴探头是理想器件,忽略了同轴探头加工精度带来的误差。为此,提出了一种更为精确的去嵌入技术,即基于传输线模型的开口同轴探头去嵌入技术,通过实测得到表征同轴探头误差的校准参量,从而量化同轴探头的误差模型,以去除在测量中同轴探头带来的误差。介绍了该技术的基本原理,并与相位补偿技术进行了对比,最终通过实测验证了该技术是有效可行的。     

超声波换能器的结构设计

介绍了一种性能良好的超声波换能器,在现有纵波探头基本结构的基础上,在内部增加高增益放大电路,并利用线路实现发射和接收的转变。实现了发射探头和接收探头可以互换的功能,避免了在应用中发射和接收探头用错而引起的探头损坏。     

菱形截面T型触探探头贯入阻力研究

T型触探是一种适用于软黏土勘察的原位测试方法。传统圆形截面探头受表面粗糙度的影响较大。为了减少探头表面粗糙度的影响,研究了菱形截面探头。假定软黏土强度服从Tresca强度条件,采用极限分析原理,求得了菱形截面探头阻力系数的解析解。结果表明,随着菱形探头轴长比的减小,探头表面粗糙度的影响逐渐减小。当轴长比小于0.8时,菱形截面探头优于圆形截面探头,从工程实用角度轴长比可取0.5。提出了菱形截面探头与静力触探机的结合方式和测试方法。     

差分和单端有源探头性能比较

本文叙述了Infinii Max探头系统,它既可用于差分检测,也可用单端检测,从而排除了过去拒用差分探头的理由。该探头系统使用可更换的探测接头,适于点测、插孔连接和焊点埋入连接的测量方式。本文从几个方面比较了差分探头和单端探头的优缺点。     

T型触探不同截面探头测量结果不确定度分析

制作圆形、轴长比为0.5的椭圆形、矩形和菱形截面T型触探探头,分别进行现场试验。采用不确定度评估方法,分析了各种可能的不确定度来源,评价了不同截面形状探头测量结果的不确定度。分析表明,不确定度主要来源于探头表面粗糙度和探头端部,探头加工带来的不确定度很小,可以忽略不计。矩形截面探头测试结果不确定度最小,椭圆形与菱形的不确定度大小相当,圆形的不确定度最大。     

示波器差分探头自动测试设计

本文以TEK公司示波器差分探头P5200为例,通过对共模抑制比CMRR参数进行详细分析,全面、系统地介绍了如何实现示波器差分探头的自动测试。与传统的手动检定相比,极大地提高工程测试的质量和效率,也为其他类型示波器探头,如电流探头,电压探头等的计量提供了一种全新的方法,具有广阔的应用前景。     

中径管母材探伤专用探头的制作

用通常的探头对中径管母材进行超声波探伤,效果不好甚至无法操作。为解决φ133×10无缝钢管的探伤问题,研制了对比试块与专用探头,应用于吉林热电厂。实践证明该专用探头的理论计算是正确的,检验结果准确可靠,探头具有实用价值。     

KPFM导电探针的制备及应用

开尔文探针力显微镜(KPFM)可以测量样品与探针之间的接触电势差(CPD),从而可以测得样品表面电势。为了更好地测量样品表面电势的微小变化,需要制备新型导电探针。金属铱稳定的化学性质与高导电率等特性能够稳定地测量尖端样品之间的电势差。实验使用物理气相沉积(PVD)的方法修饰硅探针,使针尖镀上一层厚度为纳米级的金属铱薄膜。在实验前使用透射电子显微镜(TEM)与能谱仪(EDS)对探针进行表征,证明针尖上确实存在纳米级厚度的金属铱薄膜。最后使用制备好的导电探针在超高真空的KPFM里进行硅表面的CPD测量,得到样品表面台阶电势图。     

Study on Pulse Compression Ultrasonic Imaging by a Stacked M‐Sequence Encoding Probe

If an ultrasonic imaging inside an object is possible without scanning by using an ultrasonic probe having a small aperture, the ultrasonic imaging system becomes a simpler and easier system. We have developed a stacked encoding ultrasonic transducer which can transceive an M‐sequence signal only by a pulse drive in order to realize an ultrasonic measurement with a high resolution and high sensitivity. When an ultrasonic probe with such transducer is used, a pulse compression measurement is enabled only with a general ultrasonic flaw detector and a personal computer (PC) without using special devices. In this study, we focused on the characteristic that the received waveform by this probe changes with transceiver directions of a wave. A stacked M‐sequence encoding probe of 7 bits length was manufactured and the one‐dimensional point spread function in transceiver angle was obtained. As a result, it was confirmed that this probe has not only the pulse compression characteristic, but also the angle selecting characteristic. Finally, by using the proposed probe, the cross‐sectional imaging for point objects without scanning was demonstrated.     

多通道七孔探针测速系统研究

为了满足低速流场的测速要求,基于七孔探针测速原理,设计了一套多通道七孔探针测速系统,给出了七孔探针测速系统的嵌入式硬件电路及基于Modbus通信协议的上下位机软件系统的详细设计方案,通过对传感器的压力系数标定提高了压力测量数据的一致性.在低速风洞中进行了探针标定实验,通过对标定实验数据的分析,得出探针的俯仰角和方位角的绝对误差为0.2°.并在此基础上进一步分析了探针孔径误差和传感器测量误差对系统测量结果造成的影响.     

Development of self-vibration/detection AFM probe using quartz tuning fork

We present a novel type of quartz tuning-fork probe, which oscillates and detects its own probe deformation, for atomic force microscopy (AFM) systems. The quartz tuning-fork structure was fabricated using anisotropic wet etching, and a sharp tip was formed on a beam using a focused ion beam (FIB) system. We evaluated the vibration properties of the fabricated tuning fork with the tip structure in an anti-phase vibration mode and obtained a Q-factor value of 2.5 to 2.8 × 10³. This value was one order larger than that of a conventional Si probe. We experimentally clarified that the tuning-fork probe measured a 100-nm step of the Si surface, as well as the debris with a thickness of a few tens of nanometers on the surface by self-vibration and self-detection in cyclic-contact mode AFM. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

高精度海底沉积物四点电极电阻率探针研究

海底沉积物的电阻率是现代海洋地球物理探测的重要参数。针对海底沉积物电阻率高精度测量的难点,对环形Wenner排列四点电极电阻率测量技术进行研究。利用有限元方法在有限空间柱状样内对该探针电极产生的电场强度进行仿真,并进一步实现了探针结构的优化。然后将现有文献中的电极配置因子进行了校正,以使其适用于非理想点电极且沉积物样品为有限空间时的情况。最后利用该探针进行标准KCl溶液的电导率测量实验,用以进一步验证该探针的测量精度。实验证明该技术操作方便,实用可靠,其测量相对误差小于1％。     

Eddy current testing by upgraded microloop magnetic sensor array

A micro-eddy current testing (ECT) probe, which consists of a planar microloop inductive magnetic sensor array and a pancake-type exciting coil, was developed to upgrade the ECT technology, especially as it is used for inspecting steam generator tubing in a pressurized nuclear power plant (PWR). Eddy currents and resultant magnetic fields are perturbed due to a flaw in a conductor. The flaw is detected via perturbation of the electromotive force (EMF) and phase from the array. Flaws manufactured by electric discharge machining in INCONEL 600 planar specimens, the thickness of which was 1.25 mm, were detected and reconstructed by using stacked database and simplified algorithm. Even an outer-edged 10 percent flaw could be detected. Measured EMF and phase signals were compared with numerical results obtained by using a three-dimensional eddy current and field analysis code and then verified. The experiment confirmed that the spatial resolution of detection of the micro-ECT probe is superior to that of the conventional pancake-type ECT probe. Finally, it was demonstrated that it is possible to establish the same measurement speed using the micro-ECT probe as it is by using the pancake-type ECT probe.     

数字示波器宽带探头系统的校准研究

微波射频芯片进行时域测量时,数字示波器的宽带探头是测试芯片的一个关键子系统,为准确测量芯片,必须要清楚示 波器探头系统的传输性能。 为此,设计了一种包含接地共面波导的数字示波器宽带探头校准系统,依据校准系统的信号传输特 性,用反卷积求出数字示波器宽带探头系统的频率响应,并计算其带宽,以实现对该探头系统的校准。 之后用该方法对 Keysight Infiniimax 高频差分有源探头系统进行了校准,得到其带宽数值约为 12 GHz 与标称带宽 12 GHz 相符,表明设计的校准系统合 理可行。     

Experimental studies on a structure of eddy current probe for detection of magnetic flux distorted by a flaw

Bobbin-coil-type eddy current probes, which are conventionally used for nondestructive inspection of steam generator tubes in pressurized-water-type nuclear power plants, have poor detection sensitivity to circumferential flaws. Hence a new type of eddy current probe was proposed to effectively detect the magnetic flux component that is indicative of a flaw and thus to eliminate the dependency on sensitivity in flaw detection. In the course of development of the proposed method, probe structures were investigated based on the measurement of magnetic fields induced by variously-shaped excitation flat coils. The new type of probe proposed here consists of differential pick-up coils detecting magnetic flux and excitation coils having a parallelogrammic shape. The structure of the coils was fabricated in order to detect flaws independently of their directions in trial. Nondestructive flaw detection tests were then conducted with the probe. The results obtained concrete evidence showing that both the horizontal, the vertical slit-flaws and even the small hole of 0.5 mm in diameter can be detected successfully.     

Resolution and signal processing technique of surface charge density measurement with electrostatic probe

When an electrostatic probe is used to measure the surface charge on an insulating plate of constant thickness, the measuring system is regarded a shift-invariant system and the relation between the surface charge density and the probe output can be treated in the spatial frequency domain. The distribution of the surface charge density on an insulating plate just after occurrence of a surface discharge is measured by a Pockels probe, which is regarded as a kind of electrostatic probe without the guard electrode, and restored by Wiener inverse filter. The performance of a Pockels probe and a conventional electrostatic probe are compared quantitatively in terms of the spatial resolution. In the case that the measured object is 3 mm thickness PMMA plate and is charged up to 10 nC/cm/sup 2/ in atmospheric air, it is estimated that the spatial resolution of the Pockels probe with 0.2 mm gap is 1.5 mm and that of the conventional electrostatic probe with the grounded guard electrode with 3 mm gap is 2.2 mm.     

脉冲功率装置中电容分压器的设计和应用

为了测量脉冲功率装置形成线和传输线的电压,设计和标定了自积分电容分压器和V-dot探测器。在电容分压器结构设计中,重点叙述了降低结构电感、削弱局部高电场以及保持灵敏度一致的方法。电容分压器采用在线标定,标定用电阻分压器安装在电容分压器相对于轴线对称的位置,以减小对探头位置电场分布的影响。对阳加速器水传输线、脉冲形成线和PTS单路样机中储探测器的标定和实验结果表明:无论是自积分电容分压器还是V-dot探测器,只要取值合适,同时在结构设计中注意分布参数的控制,就都可以响应前沿为几十ns至接近μs量级的信号。