磁性液体触觉传感器的设计及特性研究

磁性液体兼具液体材料的流动性和固体材料的磁性,能够在重力场和磁场的作用下长期稳定存在。磁性液体具有独特的一阶浮力特性,在磁场梯度的作用下能够悬浮起比自身密度大的非磁性物体。基于磁性液体的一阶浮力特性,设计了一种新型的磁性液体触觉传感器。当接触压力作用在悬浮触棒的非磁性触点时,悬浮触棒的移动将引起霍尔元件处的磁场变化,进而输出电压信号。该结构能够进行接触压力、表面轮廓和微小位移的同时测量。该触觉传感器体积小,相比于传统的硅片式触觉传感装置成本更低。磁性液体相比于固体材料来说,能够在系统中起到缓冲吸能的作用,进而提高了传感器系统的耐冲击性。在0~0.09 N的接触压力测量范围内,测量精度能够达到10-2 N量级,灵敏度3.34 V/N,线性度误差3.4%,迟滞误差1.4%,分辨率1.1%F.S.。     

一种高灵敏度磁性液体倾角传感器的研究

磁性液体独特的二阶悬浮力可以替代固体弹性元件为倾角传感器的惯性元件提供一个柔性弹性力,能够极大提高倾角传感器的抗冲击性能,已经在石油勘探行业成功应用。为进一步提高磁性液体倾角传感器的灵敏度,基于磁性液体的二阶悬浮特性提出了一种新的结构和检测方法,对传感器中两个永磁体间磁场的空间分布进行了理论计算和仿真,并通过试验对比分析了在选定不同参数条件下传感器的静态性能,最终得到当侧向间隙为3 mm,磁性液体注入量为1.4 g时,传感器量程为0°～50°,线性度误差为1.004 7%,灵敏度为2.3 mV/°,分辨率为0.023°,重复性误差为3.18%,工作性能最佳,且该传感器性价比高,壳体用材环保,具有很好的实用价值。     

光纤传感技术测量气液两相流持气率研究

文中提出了一种新型气液两相流体参数测试方法。传感机理为弯曲光纤的传输光功率随外界介质折射率而变化。在分析光纤弯曲波导传输光能损耗与弯曲半径、外界折射率等因素关系的基础上,提出一种 Ｕ 型结构的光纤传感器系统,并将其应用于气液两相流体持气率测试中,进行了初步研究和探讨。     

Environmental sensors based on micromachined cantilevers with integrated read-out

An AFM probe with integrated piezoresistive read-out has been developed and applied as a cantilever-based environmental sensor. The probe has a built-in reference cantilever, which makes it possible to subtract background drift directly in the measurement. Moreover, the integrated read-out facilitates measurements in liquid. The probe has been successfully implemented in gaseous as well as in liquid experiments. For example, the probe has been used as an accurate and minute thermal sensor and as a humidity sensor. In liquid, the probe has been used to detect the presence of alcohol in water.     

Modeling and characterization of piezoelectric cantilever in fluids at different temperatures

This paper introduces measurement and modeling of a piezoelectric beam used as a sensor in different types of liquids. It is immersed in different fluids at temperatures increasing from 20 °C to 50 °C. The working principle is based on detecting different resonance frequencies of the cantilever in different solutions. The oscillation of piezoelectric beam is measured using a vector network analyzer. An electrical equivalent circuit derived from a resonator model is used to simulate the experimental data. These calculated circuit constants have been related to physical properties of liquids under test. The combination of these liquids which includes non-conducting and conducting solutions, exhibiting low and high viscosity covers a good range of common physical properties of fluids. Main focus of this research is to explore the capability of piezoelectric cantilever as a liquid sensor with the influence of temperature. The equivalent circuit model has been proved to be viable to fit experimental data in non-conducting solution but less effective in conducting solution.     

ABS轮速传感器及其信号处理

分析了汽车防抱死制动系统电磁感应式轮速传感器的工作原理及其信号特征，在对轮速信号检测及其特性分析的基础上，设计了由低通滤波电路和迟滞电压比较器构成的信号处理电路，并在Multisim8．0环境下进行仿真研究，结果表明电路工作稳定可靠、抗干扰性强。     

The magnetic-distortion probe: velocimetry in conducting fluids

A new type of velocimeter, capable of local velocity measurements in conducting fluids, is introduced. The principle of the "magnetic-distortion probe" is based on the measurement of the induced magnetic field by the flow of a conducting fluid in the vicinity of a localized magnetic field. The new velocimeter has no moving parts, and can be enclosed in a sealed cap, easing the implementation in harsh environments, such as liquid metals. The proposed method allows one to probe both the continuous part and fluctuations of the velocity, the temporal and spatial resolution being linked to the actual geometric configuration of the probe. A prototype probe has been tested in a gallinstan pipe flow and in a fully turbulent flow of liquid gallium generated by the counter rotation of two coaxial impellers in a cylinder. The signals have been compared to a reference potential probe and show very good agreement both for time-averaged velocities and turbulent fluctuations. The prototype is shown to detect motion from a few cm s(-1) to a few m s(-1). Moreover, the use of the magnetic-distortion probe with large-scale applied magnetic field is discussed.     

交流励磁三维定位系统中磁传感器设计

交流励磁定位系统可以对介入式微型医疗装置在人体内的三维位置实现非接触式遥测。在定位系统中，为了测量磁场分布范围宽、下限磁场微弱的交变磁场，本文设计开发了感应线圈式磁传感器。根据电磁感应原理，感应线圈先将交变的磁信号转换为电信号，再通过后级信号处理电路在强大的噪声背景中提取出有用的电信号，结合传感器的输入输出特性，即获得待测磁场大小。实验结果表明：磁传感器能准确测量微弱交变磁场，且具有宽测量范围、高分辨率、高稳定性和高精度的优点。磁传感器还能适用于一切非导磁环境中跨度大的交变磁场的测量，具有通用性。     

Development of integrated high temperature sensor for simultaneous measurement of wall heat flux and temperature

In this paper, an integrated water-cooled sensor has been developed to simultaneously measure the heat flux and temperature at the wall of a scramjet combustor. The upgrade sensor was designed based on the principle of Gardon heat-flux gauge with many improvements. The sensor was well calibrated by both conductive heating sources and blackbody cavity device. The effects of structural material and dimensions on the sensor's responses were examined. Both the experimental measurements and numerical simulation were conducted and showed that the new sensor has the maximum measure ability of heat flux of 400 W∕cm(2) and stagnation temperatures up to 1920 K along with satisfactory response time.     

矩形脉冲涡流传感器的三维磁场量与缺陷定量评估

脉冲涡流是一种有效的电磁无损检测技术。基于脉冲涡流检测原理设计了脉冲涡流检测系统,并对矩形脉冲涡流传感器的三维磁场量进行了研究。分别在传感器的不同走向下,使用三维检测传感器获得了三维磁场量的Bx、By与Bz曲线。在传感器的不同走向下,提出使用三维蝶形图对缺陷进行检测识别。对三维信号进行特征分析后,分别在不同走向下,通过Bz曲线评估缺陷的深度。通过By与Bz曲线的特征可以测量缺陷的长度。为进一步实现飞机机身缺陷的成像检测提供了有价值的参考。     

扭转型张力转角传感器

综述了各种纱线张力测量传感器的优缺点,发明了一种全新的扭转型张力转角传感器,基于霍尔效应原理和独特的机械结构研制的一种高精度的纱线张力测量传感器.机械结构部分主要以游丝产生回复力,使传感器转轴能准确而平稳地回到起始位置点.     

Ferrofluids flow transducer for liquids

Water, being a limited and vulnerable natural resource, must be protected and economically administrated. A correct administration requires, among other things, flow measurements in order to control water consumption. Flowmeters whose characteristic equations are based on a pressure drop are generally non-linear, the flow measured not being proportional to the pressure drop. The flowmeters mostly used are those having local hydraulic resistance. Usually the local hydraulic resistance for liquid flows is obtained by decreasing the flowing section as, for example, in the Venturi tube. Although Venturi tubes have a high reliability, their disadvantages consist in the need for accurate manufacture, high price and the difficulty of replacement. These drawbacks may be avoided by realizing a flow transducer with a straight tube and a magnetic liquid manometer. In this context we present, for the first time, the operating principle and the “voltage–flow” characteristic curve of an inductive ferrofluids flow transducer for water. The transducer uses the properties of the magnetic liquid and has no moving parts (components). It can be used in steady flow conditions. The device can be adapted practically to any flow range by using a straight pipe of suitable section and an adequate U-tube manometer.     

Thermally compensated temperature sensor capable of highly accurate measurements on surfaces

A thermally compensated temperature sensor capable of highly accurate determination of surface temperatures has been demonstrated. The probe consists of a single crystal Y(3)Al(5)O(12) fiber terminating in a laser-heated Yb(3)Al(5)O(12) phosphor. It has been shown to have a measurement accuracy of approximately 1 degrees C. In principle, this device should work in the proximity as well as the contact mode.     

偏置磁场对磁致伸缩液位传感器检测电压的影响

为了提高磁致伸缩液位传感器的检测精度,研究了磁致伸缩液位传感器中产生偏置磁场的浮子磁铁的放置方式及其对检测电压的影响。利用ANSYS软件对浮子磁铁不同放置方式下形成的偏置磁场进行了有限元分析,分析显示:采用3块磁铁互成120°N极N极S极(NNS)放置或者采用圆环磁铁作为偏置磁场时检测效果比较理想。实验研究了磁致伸缩液位传感器的偏置磁场对检测电压的影响,并在浮子磁铁不同放置方式下进行多次实验。结果表明:偏置磁铁为3块磁铁互成120°NNS放置时或者为圆环磁铁时,检测电压的幅值达到50mV,比其它放置方式提高了近30mV。研究表明:磁致伸缩液位传感器应选择3块磁铁NNS放置或者选择圆环磁铁作为偏置磁场。     

泡沫液位传感器的研制

泡沫是一种特殊的两相流形态，其力学、热学、光学等多种性能均与单相气体或液体有很大区别，由于泡沫的形成机理多样、性质变化复杂，至今尚无完善的研究理论体系，泡沫的液位测量在国内外也是一个空白。开发了一种基于传热原理的测量泡沫液位的传感器，介绍了传感器的构造和原理，以及测量误差和动态响应的计算分析。     

旁路励磁的钢缆索索力传感器磁路分析

基于钢缆索逆磁致伸缩索力测量原理,讨论了一种旁路励磁的索力传感器。用磁导分析法对磁路做了详细的推导,结果表明可通过检测感应线圈的感应电压反映材料所受的外力,传感器输出与外力信号本身的变化、感应线圈的匝数、材料截面积、外激励磁化场及该磁场下的材料磁导率有关。在外力是缓慢变化情况下,可通过求感应积分电压得到外力;从激励磁化方式、参考工作点的选取,传感器的尺寸设计原则等三个方面做了讨论,确定传感器的参数。最后,利用万能拉力机对该种结构的传感器做了拉力模拟实验,实验结果表明旁路励磁的传感器磁路分析与参数设计比较合理,可用于钢缆索的索力测量。     

A combined surface stress and magneto-optical Kerr effect measurement setup for temperatures down to 30 K and in fields of up to 0.7 T

An optical 2-beam surface stress measurement and magneto-optical Kerr-effect has been combined with a liquid helium cooled cryostat. Sample temperatures down to 30?K and magnetic fields up to 0.7?T are achieved under UHV conditions. Low temperatures are exploited to obtain the first experimental data on the surface stress change induced by the adsorption of the noble gas Xe on Pt(111). High magnetic fields and low temperatures are used to characterize the magnetic properties of Co monolayers in longitudinal and polar Kerr geometries. The effective magnetic anisotropy is extracted from hard axis magnetization loops.     

厚膜电容式集成压力传感器压元件研究

采用厚膜技术研制新型电容式集成压力传感器用感压元件。具有抗干扰能力,灵敏度高,受分布电容、寄生电容影响小、耐腐蚀,耐高温的特点。文中主要介绍其电容式感压元件的原理、设计,并对非线性等相关技术及工艺问题进行了探讨。     

光纤磁场传感器的磁场探头设计

光纤磁场传感器的探头是光纤磁场传感器中最关键的部分，它直接影响到传感器的测量精度。根据光纤传感器的测量要求和磁敏元件(磁光晶体：BiGd：YIG-Y3-x-yBixGdyFe3O12)的工作原理及特点，必须在光纤磁场传感器探头中产生线偏振光，同时为了在磁敏元件加入传感器探头后不至于增加固有损耗，故在探头两端使用了两个光纤准直器。介绍了在探头设计中，各部分的工作原理和结构特点。     

An ultralow noise current amplifier based on superconducting quantum interference device for high sensitivity applications

An integrated ultrahigh sensitive current amplifier based on a niobium dc superconducting quantum interference device (SQUID) has been developed. The sensor design is based on a multiturn signal coil coupled to a suitable SQUID magnetometer. The signal coil consists of 60 square niobium turns tightly coupled to a superconducting flux transformer of a SQUID magnetometer. The primary coil (pick-up coil) of the flux transformer has been suitably designed in order to accommodate the multiturn input coil. It has a side length of 10 mm and a width of 2.4 mm. In such a way we have obtained a signal current to magnetic flux transfer coefficient (current sensitivity) as low as 62 nA∕Φ(0). The sensor has been characterized in liquid helium by using a direct coupling low noise readout electronic and a standard modulated electronic in flux locked loop configuration for the noise measurements. Beside the circuit complexity, the sensor has exhibited a smooth and free resonance voltage-flux characteristic guaranteeing a reliable and a stable working operation. Considering a SQUID magnetic flux noise of S(Φ)(1∕2) = 1.8 μΦ(0)∕Hz(1∕2) at T = 4.2 K, a current noise as low as 110 fA∕Hz(1∕2) is obtained. Such a value is about a factor two less than the noise of other SQUIDs of the same category. As an application, Nyquist noise measurements of integrated test resistors using the current sensing noise thermometer technique are reported. Due to its high performance such a sensor can be employed in all applications requiring an extremely current sensitivity like the readout of the gravitational wave detectors and the current sensing noise thermometry.