超声波对石英晶体微天平响应性能的影响

该文以阻抗分析法研究了超声波对石英晶体微天平(QCM)响应特性的影响,结果表明,在超声波存在时QCM的纵波传播与反射受到干扰,QCM的阻抗-频率曲线上出现很多的毛刺干扰波,使QCM的信噪比下降.当采取消除纵波干扰的措施后,毛刺干扰波消失,实验测试了QCM的谐振频率及动态电阻对表面质量负载变化及液体粘度、密度改变的响应,证实超声波对QCM的厚度剪切模式无影响.QCM应用于监测表面活性剂去除油污膜的过程,结果表明在超声波作用下油污膜的去除速率大幅度提高.     

基于QCM的湿度传感器等效电路模型研究

基于石英晶体微天平(QCM)的湿度传感器是一种以石英晶体为核心元件的新型高灵敏度传感器.根据气相中晶体振荡电路的起振和稳定条件,对晶体表面敏感薄膜吸附水分时等效电路参数的变化进行建模,得到了一种新型的基于QCM的湿度传感器等效电路模型.通过电路仿真软件PSPICE对模型进行仿真,并搭建QCM湿度传感器实验测量平台,结果验证了基于QCM的湿度传感器等效电路模型的有效性和正确性,对QCM湿度传感器的振荡电路的进一步设计和优化具有指导意义.     

基于π网络零相位法石英晶体激励电平相关性的研究

本文阐述了基于π网络零相位法石英晶体测量中改变激励电功率对石英晶体电参数的影响.主要以π网络零相位法为测量方法,配以软件调节,硬件补偿等措施改变施加在石英晶体两端的激励功率,从而完成激励功率相关性的研究.重点阐述系统电阻校准方法和串联谐振电阻的测量.     

测定DMMP的PMPS-QCM传感器的研究

研究了新型敏感材料PMPS对神经性毒剂模拟剂甲基膦酸二甲酯(DMMP)的响应特性.在石英晶体微天平(QCM)的电极上滴涂上PMPS溶液得到敏感膜,发现QCM当响应、恢复时间为30-60 s时,可以产生大约11.83 Hz/ppm(ppm i.e.×10-6)的频率响应,理论上LOD为0.25 ppm(ppm i.e.×10-6),并具有较好的重复性和选择性.该实验结果表明,与PVDF相比,PMPS是一种更适宜检测DMMP的敏感材料.     

基于PVDF膜的QCM对DMMP的气敏特性研究

神经性毒剂是化学战剂的重要分支.为了检测神经性毒剂模拟剂甲基膦酸二甲酯(DMMP),使用毛细管在压电石英晶体(QCM)的电极上滴涂上不同质量的聚偏氟乙烯(PVDF)溶液,干燥后作为敏感膜.室温下测试QCM对不同浓度的DMMP的响应情况,发现QCM的频率变化与气体浓度有着良好的线性关系.该实验结果表明,PVDF可以作为检测DMMP的很好的敏感材料.     

高灵敏度QCM在阻尼介质中的分辨率改进

为改进晶体谐振器在阻尼介质中频率的稳定性和分辨率,研究了分辨率和干扰频率的理论关系,采用D触发器设计混频电路来减小回路的噪音干扰,由此分析了石英晶片上附着微小质量和液体时的等效电路,并制作了QCM传感器,得到了电路响应曲线;取4MHz、10MHz的谐振器在液体中进行了试验。结果表明:提高晶体谐振器的分辨率,减小噪音在谐振器中的出现比提高频率更有效。     

基于兀网络零相位法石英晶体激励电平相关性的研究

本文阐述了基于Ⅱ网络零相位法石英晶体测量中改变激励电功率列石英晶体电参数的影响。主要以Ⅱ网络零相位法为测量方法，配以软件调节，硬件补偿等措施改变施加在石英晶体两端的激励功率，从而完成激励功率相关性的研究。重点阐述系统电阻校准方法和串联谐振电阻的测量。     

液相QCM生物传感器电路系统设计

设计的石英晶体微天平（ QCM）仪器主要用于微量物质在液体中的生物化学反应的测量,根据液相QCM生物传感器的需要完成了电路系统部分的设计,选用Microchip的单片机为液相QCM生物传感器的电路系统的核心,主要包括电源部分、信号激励与接收部分、温控部分,实现了石英晶体的激励和频率的检测、温度的采集与控制等功能。上位机检测结果显示：实际温度控制精度误差为0.2℃,能顺利检测到最佳谐振频率,表明该系统能够较好地达到预期的要求。     

石英谐振器力-频特性与结构参数的关系

用绝热水套悬挂装置测试了石英晶体的力-频特性。实验表明,沿厚度方向剪切振动的AT切石英晶体谐振器的力-频特性与激励电平及电极大小无关;泛音振动下谐振器的力敏系数的增加与泛音次数的增加不成严格的倍数关系;晶体的活力与晶体外形、振动频率、电极面积及受力无关。     

多通道QCM信号采集与处理系统设计

为充分提取石英晶体微天平（QCM）输出信号所蕴含的信息,利用Visual C＋＋6．0设计了信号采集与处理程序,用高速A／D采集卡PCI8002对多通道QCM的模拟差频信号进行采样。通过对采集到的大量数据的分析计算,在获得各通道较高精度振荡频率的同时,还可获得电压幅值等参数,为样品特性的深入分析打下了基础。     

ZnO纳米棒修饰的QCM气体传感器检测NH_3研究

主要介绍了ZnO纳米棒修饰的石英晶体微天平(QCM)气体传感器的制备与测试。采用两步法在石英晶振片表面制备直径为100 nm的ZnO纳米棒敏感膜,构成QCM NH3传感器。检测系统为自主研发的基于LabVIEW平台的QCM气体传感器频率测试软件。检测NH3的体积分数为5×10-6~50×10-6,响应时间均在10 s以内,最大频差值为10.9 Hz,响应最大频差值与NH3体积分数呈现良好的线性关系。室温条件下,ZnO纳米棒敏感膜可以完全实现吸附解吸过程,具有可逆性。该传感器性能稳定,响应灵敏,具有重复性。     

Polyaniline–TiO2 nano-composite-based trimethylamine QCM sensor and its thermal behavior studies

Inorganic/organic composites are very attractive due to synergetic behavior and a wide range of potential use. A polyaniline–TiO₂ nano-composite, obtained by combination of chemical polymerization and a sol–gel method, was deposited on the electrode of quartz crystal to implement a quartz crystal microbalance (QCM) chemical sensor. The morphology of the composite film was studied by scanning electron microscopy (SEM) measurements. The coated quartz crystal and a non-coated quartz crystal were mounted in a sealed chamber, and their frequency difference was monitored. When analyte vapor was injected into the chamber, gas absorption decreased the frequency of the coated quartz crystal and thereby caused an increase of the frequency difference between the two crystals. The frequency difference change response towards trimethylamine was evident and could be recovered by N₂ purgation easily. The calibration curve towards trimethylamine, its long-term stability and selectivity were investigated. The thermal behavior of the sensing characteristics was compared with that of a polyaniline QCM sensor. Fourier transform infrared (FTIR) spectra of polyaniline and polyaniline–TiO₂ nano-composite and QCM data under various conditions were used to study the effect of thermal treatment.     

Out-of-plane vibrations of quartz resonators used in quartz crystal microbalance measurements in gas phase

The article reveals that shear-mode quartz crystal resonators, currently used in quartz crystal microbalance (QCM) measurements, exhibit an out-of-plane vibration without being in contact with a liquid. Laser assisted CVD was used to deposit carbon-nanoparticles on the surface of a quartz resonator. The in-plane, shear vibration of the quartz resonator, produces a mega-gravity acceleration which induces a sedimentation of the carbon-nanoparticles, while the out-of-plane vibration produces a mega-gravity acceleration, normal to the crystal surface, which induces an expelling of the deposited carbon-nanoparticles. The two opposite effects reveal a complex situation on the quartz resonator surface in QCM measurements.     

适体和蛋白质解离常数检测方法比较分析

对基于石英晶体微天平（QCM）生物传感器的两种检测核酸适体与蛋白质解离常数方法进行了比较,提出来一种更加精确合理的检测流程。以凝血酶和凝血酶适体 TBA15为模型,耗散型石英晶体微天平（QCM-D）为传感器,实时检测末端修饰巯基适体的固定、表面封闭剂对非特异性结合位点封闭以及两种不同的蛋白进样方式引起的频率响应,实验数据拟合得到解离常数。不同蛋白的进样方式得到的解离常数不同,非特异性位点的封闭也同样影响解离常数的检测。从低浓度到高浓度依次通入固定体积蛋白的进样方式,实验重复性高且消耗样品量小于1μg,是较为理想的检测方式。     

Mixed self-assembled lipopolymers with spacer lipids enhancing sensitivity of lipid-derivative QCMs for odor sensors

An odor sensing system using a quartz crystal microbalance (QCM) sensor array and pattern recognition technique has been for years a main research topic in our group. For the general field of artificial olfaction using acoustic-wave based sensors such as QCMs it is vital to search for novel sensing materials. Here we present recent results of our ongoing study on application of pegylated lipids as coatings for QCM odor-sensors. The method presented herein is based on self-assembling of lipids and lipid-derivatives on the QCM surfaces. The disulphide-terminated lipids and lipopolymers are co-chemisorbed onto gold electrodes of QCM sensors by simple immersion in ethanolic solutions. This creates porous supports onto which additional layers of lipopolymers are physisorbed. The method allows for fabrication of lipopolymeric QCM odor-sensors with enhanced sensitivity to odorants, capable of very good discrimination among odorant samples—according to the functional group of an odorant.     

采用聚吡咯修饰的QCM型三甲胺气体传感器

三甲胺是评估肉类食品新鲜度的重要指标之一,并且临床上也比较值得关注,因而三甲胺的检测具有十分重要的意义,为此,我们采用乳聚法制备了聚吡咯材料,并将其涂敷在晶振电极表面后制得敏感石英晶体微天平(QCM).根据敏感QCM和参比QCM间的频率差变化来实现气体的检测.在室温条件下,该气体传感器对三甲胺气体具有较明显的响应.实验从灵敏度、重现性、选择性和稳定性等方面出发,对该传感器的的性能进行了评价.结果表明,虽然传感器的制备方法简单,但它的性能优异.     

Comparison of surface plasmon resonance spectroscopy and quartz crystal microbalance for human IgE quantification

Surface plasmon resonance (SPR) and quartz crystal microbalance (QCM) have been known independently as surface sensitive analytical devices capable of label-free and in situ bioassays. In this study a SPR device and a 10 MHz QCM sensor are employed for the study of human IgE and anti-human IgE-binding reactions upon immobilizing the latter on the gold electrodes. The SPR and QCM response curves to the antibody immobilization and antigen binding are similar in shape but different in time scale, reflecting different resonation principles. Through optimization of the anti-human IgE coating, both the SPR and QCM sensors could detect IgE in a linear range from 5 to 300 IU/ml. Although the intrinsic sensitivity of the SPR device is five times of the 10 MHz QCM, the IgE detection sensitivity of the two methods is, however, different only in a factor of 2. The acceptable QCM sensitivity for the IgE detection is attributed to the fact that QCM measures the sum of molar mass of a protein layer and the entrapped water. Although both the devices use open, stand still liquid cell, and all the measurements are performed at room temperature, the SPR reproducibility and reliability are better than QCM, as the QCM frequency is more sensitive to temperature fluctuations, press changes and mechanical disturbances.