双端调谐音叉石英谐振器的结构设计方法研究

叙述了双端调谐音叉石英振梁式重力传感器的结构和工作原理。根据石英谐振器的谐振频率公式和石英晶体的压电效应原理，确定了石英谐振器的主要结构尺寸和电极设置。应用有限元法计算了该谐振器的谐振频率，显示了一阶模态振型，这为设计不同用途的石英振梁式加速度传感器提供了理论依据。     

基于SH-SAW谐振器的无线温度传感器研究北大核心CSCD

基于128°YX铌酸锂压电衬底设计制作了窄带、高Q值的水平剪切声表面波(SH-SAW)谐振器,研究了其温度特性,并基于该谐振器制作了无线温度传感器。研究结果表明,该SH-SAW谐振器在常温至250℃内保持良好的谐振性能,频率温度系数为-24.33 kHz/℃。基于该SH-SAW的无线温度传感器在常温至250℃温度范围内实现了温度的准确无线测试,测温误差为0.93%,且具有良好的重复性。     

基于SH-SAW谐振器的无线温度传感器研究

基于128°YX铌酸锂压电衬底设计制作了窄带、高Q值的水平剪切声表面波(SH-SAW)谐振器,研究了其温度特性,并基于该谐振器制作了无线温度传感器。研究结果表明,该SH-SAW谐振器在常温至250℃内保持良好的谐振性能,频率温度系数为-24.33 kHz/℃。基于该SH-SAW的无线温度传感器在常温至250℃温度范围内实现了温度的准确无线测试,测温误差为0.93%,且具有良好的重复性。     

电子式互感器数字接口的研究与设计

数字化变电站中电子式互感器与二次设备的数字接口是变电站自动化技术的一个关键点,该文分析了电子式互感器标准和IEC61850标准中对数字量输出的要求,并给出数字接口数字量通信帧的实现方案。在此基础上,提出了一种基于现场可编程门阵列（FPGA）和数字信号处理（DSP）技术的接口设计方案,详细介绍了硬件和软件设计方法。试验结果表明,该方案可以很好地实现数字接口。     

石英音叉传感器测量流体密度和黏度的研究

文中基于石英音叉传感器测量流体密度和黏度的理论,搭建了实验测试平台,验证了该传感器可同时测量流体密度和黏度的可行性.另外,实验测量了石英音叉谐振频率受温度影响的程度,为石英音叉传感器在更高温度下测量流体的密度和黏度提供温度校准依据.实验结果表明:当流体温度20～80℃变化时,石英音叉传感器测量5种流体密度的相对误差基本...     

使用机械谐振器的精密力传感器

<正>本文是叙述某种对称"双端谐振器音叉"谐振器的原理和特性(铁镍合金的机械型式石英晶体蚀刻型),以及将它们的做为压力传感器的运用。其温度系数和漂移非常小,输出信号——频率很容易测量准确。经微处理器线性化传感器特性——对铁镍合金型传感器线性在量程的0.001%之内。概论机械谐振器式的传感器早已被用于各种场合(Halford, 1964; Paros, 1973);它有着极好稳定性,很小的漂移或滞后,以及易于数字化输出(即,频率)——传感器的特性曲面很容易使用微处理器实现线性化。由于谐振频率是随加至轴向的力     

石英音叉液体密度传感器的阻抗谱测量

阐明了石英音叉液体密度传感器的工作原理,制备了石英音叉液体密度传感器探头,设计了以AD5933为核心的石英音叉密度传感器的阻抗谱测量系统,主要包括阻抗测量电路、信号调理电路、量程自动切换电路,结合人机交互模块,可以实现参数设置、数据处理和显示。最后测试实验表明,该阻抗谱测量系统具有较高的精度和稳定性。     

高精度光谱辐射计测量超低光谱透过率

设计并研制了一种基于光栅双单色仪的高精度全自动单光束光谱辐射计。该仪器主要由高稳定氙灯、带有快门的单光阑屏、石英透镜、中性减光片、紫外光栅双单色仪、光电探测器及电控系统组成,测量光谱范围为200~400 nm, 可以实现10^-6~10^-8量级光谱透过率高精度测量,测量过程由自行编制的计算机软件进行自动控制,能实现全自动单光束测量。给出了该仪器的测量原理、测量方法及数据处理方法。利用该仪器测量了紫外滤光片样品的光谱透过率,分析了测量不确定度。实验结果表明,该仪器测量精度高、速度快、测量合成标准不确定度＜3.16×10^-3,完全满足测量精度要求,可应用于对精度要求高的紫外滤光片光谱透过率的测量。     

一种新型高性能石英音叉温度传感器

文中阐述一种关于弯曲振动模式的石英音叉温度传感器的新型设计方案 ,该传感器用新的切型ZY(110°/10°)进行设计的弯曲振动模式的传感器优于其它切型 ,并对提高传感器的和减少环境等效电阻进行理论分析。采用可变结构方式调制传感器精确频率 ,同时提高传感器的灵敏度和减少非线性     

基于石英音叉温度传感器的测温仪表的设计与实现

介绍了一种基于音叉谐振式温度传感器的测温仪表电路的设计与实现.为了提高精度,降低功耗,采用MicroChip公司低功耗单片机PIC16F877和等精度数字频率测量原理设计仪表的硬件和软件,使测量精度达到0.5‰,同时系统功耗更小(<200μA).仪表在实际的应用中取得了较好的效果.     

Force-gradient-induced mechanical dissipation of quartz tuning fork force sensors used in atomic force microscopy

We have studied the dynamics of quartz tuning fork resonators used in atomic force microscopy taking into account the mechanical energy dissipation through the attachment of the tuning fork base. We find that the tuning fork resonator quality factor changes even in the case of a purely elastic sensor-sample interaction. This is due to the effective mechanical imbalance of the tuning fork prongs induced by the sensor-sample force gradient, which in turn has an impact on dissipation through the attachment of the resonator base. This effect may yield a measured dissipation signal that can be different from the one exclusively related to the dissipation between the sensor and the sample. We also find that there is a second-order term in addition to the linear relationship between the sensor-sample force gradient and the resonance frequency shift of the tuning fork that is significant even for force gradients usually present in atomic force microscopy, which are in the range of tens of N/m.     

A New Method for Measuring Normal Forces with Accurate Gap Control Using a Microfabricated Quartz Resonator for Lubrication at Nanometer Gaps

A new method using a microfabricated quartz double-ended tuning fork (DETF) resonator is presented for simultaneously measuring normal and lateral forces with accurate gap control. The quartz resonator provides high force sensitivity due to its smaller device size. An optical fiber probe for lateral force detection was combined with the resonator by adding a support frame, thereby for increasing lateral rigidity. The normal and lateral forces exerted by a lubricant in nanometer-sliding gaps were simultaneously measured using the quartz DETF resonator with the optical fiber probe. This method is useful for clarifying the tribological properties in small sliding gaps for micro/nano-mechanical devices such as the head–disk interface of hard disk drives.     

Computer simulation of a piezoelectric angular rate sensor

The paper presents the finite element (FE) modeling of operation of a rotational motion sensor that uses a balanced oscillator (tuning fork) to sense the angular rate. The 3D FE model has been employed for the investigation of the dynamic properties of the sensor. The sensitivity functions have been obtained for adjusting the geometric parameters of the quartz element in order to achieve the desired values of natural frequencies. The performance of dynamic computations has been improved by truncating the dynamic contributions of higher modes of the vibrating structure.

Results are presented in terms of performance characteristics of the sensor against the design parameters in various modes of operation.     

Atomic resolution ultrafast scanning tunneling microscope with scan rate breaking the resonant frequency of a quartz tuning fork resonator

We present an ultra-fast scanning tunneling microscope with atomic resolution at 26 kHz scan rate which surpasses the resonant frequency of the quartz tuning fork resonator used as the fast scan actuator. The main improvements employed in achieving this new record are (1) fully low voltage design (2) independent scan control and data acquisition, where the tuning fork (carrying a tip) is blindly driven to scan by a function generator with the scan voltage and tunneling current (I(T)) being measured as image data (this is unlike the traditional point-by-point move and measure method where data acquisition and scan control are switched many times).     

一种新型固支结构石英音叉陀螺的设计

石英音叉陀螺的固支结构对陀螺器件的性能影响很大.提出一种新型固支结构的石英音叉陀螺,把固支结构的支撑梁设计在元件拾取运动零位移线处,目的在于提高陀螺对外界振动和温度变化的抗干扰能力,从而改善零位稳定性.运用ANSYS软件对新结构做仿真验证,结果表明新结构在元件灵敏度、抗振动等重要性能上都有一定提高.新结构同时能缩短元件制造流程,更易工程实现.     

Design and Characterization of a Novel Z-axis Quartz Cross-fork Micromachined Gyroscope

The existing researches on quartz gyroscope mainly focus on the structure design of the tuning fork, which aim at obtaining a better vibration characterization. However, the fabrication of complicated structure is a challenge for present processes, and the imperfect fabrication process seriously affects the performances of the sensors. In this paper, a novel quartz cross-fork structure micromachined gyroscope is proposed. The sensor has a simple structure in x-y plane of quartz crystal. Unlike other quartz ...     

Ultra stable tuning fork sensor for low-temperature near-field spectroscopy

We report on a distance control system for low-temperature scanning near-field optical microscopy, based on quartz tuning fork as shear force sensor. By means of a particular tuning fork-optical fiber configuration, the sensor is electrically dithered by an applied alternate voltage, without any supplementary driving piezo, as done so far. The sensitivity in the approach direction is 0.2nm, and quality factors up to 2850 have been reached. No electronic components are needed close to the sensor, allowing to employ it in a liquid He environment. The system is extremely compact and allows for several hours of stability at 5 K.     

Trace gas detection based on off-beam quartz enhanced photoacoustic spectroscopy: optimization and performance evaluation

A gas sensor based on off-beam quartz enhanced photoacoustic spectroscopy was developed and optimized. Specifically, the length and diameter of the microresonator tube were optimized, and the outer tube shape is modified for enhancing the trace gas detection sensitivity. The impact of the distance between the quartz tuning fork and an acoustic microresonator on the sensor performance was experimentally investigated. The sensor performance was evaluated by determining the detection sensitivity to H(2)O vapor in ambient air at normal atmospheric pressure. A normalized noise equivalent absorption coefficient (1σ) of 6.2×10(-9)?cm(-1)?W/Hz(1/2) was achieved.     

Integrated electronic transport and thermometry at milliKelvin temperatures and in strong magnetic fields

We fabricated a He-3 immersion cell for transport measurements of semiconductor nanostructures at ultra low temperatures and in strong magnetic fields. We have a new scheme of field-independent thermometry based on quartz tuning fork Helium-3 viscometry which monitors the local temperature of the sample's environment in real time. The operation and measurement circuitry of the quartz viscometer is described in detail. We provide evidence that the temperature of two-dimensional electron gas confined to a GaAs quantum well follows the temperature of the quartz viscometer down to 4 mK.