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.     

石英晶体微天平在蛋白吸附领域的研究进展

石英晶体微天平(Quartz Crystal Microbalance,QCM)是一类重要的质量敏感型传感器,其检测限可以达到10%～9g,具有特异性好、灵敏度高、样品无需标记和操作简便的优点.QCM最初应用于气相反应环境,从20世纪80年代开始逐步用于液相反应环境之中,现在已经广泛应用于环境监测和生物医学等各个领域.QCM用于蛋白吸附领域的研究,可以实时动态地监测蛋白吸附的整个过程,包括吸附蛋白的质量、吸附层的厚度、粘弹性变化信息及吸附蛋白的构象变化等等.本文就QCM的原理、应用和蛋白吸附的研究现状进行了简要介绍,综述了近几年QCM用于蛋白吸附领域的研究现状,并对其发展进行了展望.     

阻抗分析中激励电平对石英晶体微天平响应性能的影响

阻抗分析法是表征石英晶体微天平(QCM)响应特性的主要手段之一,能够给出QCM的谐振频率及其等效电路参数.在阻抗计分析法诸多测定仪器参数中,施加在石英晶体上的激励电位水平对测定结果的影响少见文献讨论.最近有文献报道称激励电平是一个很关键的测量条件,对QCM的粘度响应模式存在明显的影响.该文系统测定了激励电平对QCM的等效电路参数值以及QCM对表面质量、溶液粘度的影响,结果表明,在5～1 000 mV范围内改变施加在QCM上的激励电平,对QCM的响应特性影响很小,为QCM的阻抗分析中的参数设置提出不同的见解.     

基于有限元分析QCM电极尺寸的优化设计

提出了一种优化石英晶体微天平(Quartz Crystal Microbalance,简称QCM)结构、抑制寄生振动模的设计方法.用Ansys9.0有限元软件直接对QCM进行三维有限元分析,从而避免了一般解析和半解析中对控制方程的简化.首先通过对QCM谐振频率收敛性的分析,验证了有限元计算的正确性;然后分析了不同电极尺寸对QCM振动及能陷情况的影响,并找到了较佳的电极尺寸;最后针对不同电极尺寸的QCM进行了液体测量实验,实验结果验证了基于有限元分析QCM电极尺寸设计方法的有效性.     

基于相关性原理QCM频谱分析系统的设计

介绍了一种新型的QCM(Quartz Crystal Microbalance)频谱分析系统的设计,它具有结构简单,实时性好,抗干扰性强,应用领域广,精度高等特点.文中对最小阻抗频率等同谐振频率的合理性做了分析,提出了基于相关性原理采集QCM微弱有用信号的方法,设计了QCM频谱分析系统的结构.最后进行了液体测量实验,实验结果与理论值基本一致,从而证实了此设计的正确性.     

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。     

基于QCM传感器的液压油品质在线监测系统的开发

提出了一种利用QCM传感器对液压油品质进行在线监测的新方法,给出了系统软、硬件的设计方案 并且设计了适用于油液中的QCM振荡电路。     

电化学石英晶体微天平(EQCM)原理及应用中的几个问题

简要介绍了电化学石英晶体微天平(EQCM,electrochemical quartz crystal microbalance)的工作原理,并针对其在应用中经常遇到的几个问题进行了深入讨论.比较起单纯的电化学分析方法,EQCM系统中QCM元件与溶液接触的电极同时充当了电化学体系的工作电极及石英晶体振荡器的电极两个角色,从而在进行电化学实验的过程中,可同时得到氧化/还原电流及QCM频率两个参量.通过对这两个参量的综合分析,可更好地对电化学过程中的各种离子/分子在电极表面行为进行分析.由于EQCM同时利用了电化学检测的高灵敏度及QCM的可实时检测表面质量及阻尼的特点,在生物化学量的检测中具有非常好的应用前景.     

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LiCl湿敏涂层的QCM湿度传感特性的研究

对0.2%质量比LiCl薄膜涂层的QCM湿度传感单元湿敏特性进行了系统性的研究。研究结果表明:0.2%质量比LiCl—QCM的湿度传感单元的线性测量范围为13%～94%RH,克服了常规LiCl湿敏材料传感单元量程窄的缺点。另外,此湿度传感单元还具有重复性好、灵敏度高、湿滞小(小于10 Hz)、数字频率化输出等优点,因而,具有较好的潜在应用前景。     

QCM 气体传感器的优化设计及应用研究

本文主要介绍了一种新型的石英谐振气体传感器 QCM(Quartz Crystal Microbalance) .它具有灵敏度高、稳定性好、抗干扰能力强等特点 ,可用于多种领域 ,本文主要根据计算化学方法 ,研究其对呼吸气体的响应特性 .此外 ,采用电化学方法制备传感器敏感膜 ,设计了相应的测量系统 .从实验结果可看出这一传感器对呼吸气体的响应结果是令人满意的 ,具有实际应用前景     

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.     

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.     

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.     

Plastic antibodies as chemical sensor material for atrazine detection

Self-organization of monomers around template molecules, in bulk MIP generation, leads to selective molecular imprints with high sensitivity. Employing the host–guest chemistry, novel artificial receptors were fabricated via in situ MIP synthesis directly on gold electrodes of piezoelectric transducers (quartz crystal microbalance, QCM). The resultant label-free and robust biomimetic sensing material shows reversible as well as selective sensor responses for chlorotriazines moieties with minor structural differences. A detection limit of 20 ppb for atrazine was attained while showing selectivity up to 9 times higher than its metabolites des-ethyl-atrazine (DEA), des-isopropyl-atrazine (DIA), des-ethyl-des-isopropyl-atrazine (DEDIA) and structural analogues like simazine (SIM) and propazine (PRO). Furthermore, imprinted nanoparticles give linear characteristics over the wide range and show no saturation effects in comparison to bulk materials.     

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.     

Policy‐directed certificate retrieval

Any large scale security architecture that uses certificates to provide security in a distributed system will need some automated support for moving certificates around in the network. We believe that for efficiency, this automated support should be tied closely to the consumer of the certificates: the policy verifier. As a proof of concept, we have built QCM, a prototype policy language and verifier that can direct a retrieval mechanism to obtain certificates from the network. Like previous verifiers, QCM takes a policy and certificates supplied by a requester and determines whether the policy is satisfied. Unlike previous verifiers, QCM can take further action if the policy is not satisfied: QCM can examine the policy to decide what certificates might help satisfy it and obtain them from remote servers on behalf of the requester. This takes place automatically, without intervention by the requester; there is no additional burden placed on the requester or the policy writer for the retrieval service we provide. We present examples that show how our technique greatly simplifies certificate‐based secure applications ranging from key distribution to ratings systems, and that QCM policies are simple to write. We describe our implementation, and illustrate the operation of the prototype. Copyright © 2000 John Wiley & Sons, Ltd.