基于单片机的石英晶体微天平气体检测系统设计

在对石英晶体微天平(QCM)的工作原理和检测方法进行了研究之后,本文提出采用参比QCM补偿的方法来克服温湿度等非质量因素对测量结果的影响,并研制了以MSP430F112单片机为核心的低成本的QCM气体检测系统.详细阐述了该系统的硬件结构和软件设计.为验证系统设计的合理性,用聚苯胺作为敏感材料制备了QCM氨传感器,通过并使用该系统对它性能进行检测.结果表明,与QCM传感器一起配合,该系统可以用来检测环境中气体的浓度.     

QCM露点传感器水粘性影响的抑制方法研究

为了解决基于主控温式的石英晶体微天平（Quartz Crystal Microbalance， QCM）露点测量系统中冷凝水粘弹特性影响露点识别准确性的问题，对QCM电极进行疏水处理，改善凝结特性，减小水粘性引起的频率耗散，实现液态水质量变化引起的谐振频率偏移测量。在QCM电极上制备静态水接触角为133° ± 2°的疏水层并对其进行表征，将疏水电极与未经处理的电极用于露点识别实验，并与精密露点仪获得的标准露点进行比对。实验证明，通过疏水处理电极凝结面的方法能够有效提升QCM露点传感器的露点识别精度，为主控温式露点传感器结构的优化设计提供理论和实验依据。     

空间用油脂材料原位质损测试及出气成分分析方法

QCM（QuartzCrystal Microbalance）作为一种新型的高灵敏度质量传感器,具有测量精度高、稳定性好、体积小和工作温度范围广等优点,被用来监测微小质量的变化。针对QCM的原理,提出了将空间用油脂材料包裹在QCM电极上,在空间材料出气成分分析设备中原位监测材料的质损和出气成分的方法,并对实验方法进行了验证。     

低温空气等离子体改性PDMS的研究

为了改善聚二甲基硅氧烷（PDMS）的亲水性和稳定其电渗性能,采用空气微波等离子体在低温条件下对其表面进行改性。利用原子力显微镜（AFM）、X射线光电子能谱（XPS）及静态接触角对处理前后的PDMS进行分析。经空气微波等离子体处理3min后,PDMS的亲水性得到极大的改善,水在其表面的接触角接近零度。XPS结果表明：处理后PDMS表面形成SiOx薄层;AFM显示空气等离子体处理对PDMS的表面没有损伤。与文献报道的高、中真空氧等离子体处理方法相比,亲水效果基本一致,却大幅度降低了对设备真空系统的要求,并缩短了操作时间,节约了成本。最佳处理条件为：微波为100W,腔体内气压为1.0kPa,空气的流量为20sccm（1sccm=1cm3·min^-1）,时间3min。     

长程表面等离子体共振技术在检测大肠杆菌浓度中的应用研究

建立了一种基于长程表面等离子体共振技术检测大肠杆菌浓度的方法及系统。基于此,制备了能够产生长程表面等离子体共振效应的双层膜传感芯片,并在实验上将长程表面等离子体共振(LSPR)和传统表面等离子体共振(CSPR)两种生物传感器的性能进行了对比。结果表明LSPR生物传感器共振曲线的平均半高宽比CSPR传感器共振曲线的平均半高宽窄1.79倍,且其灵敏度是CSPR的2倍。由此,证实了基于LSPR的生物传感器对大肠杆菌浓度的改变更加敏感。此外,该方法分辨率高,试剂用量少,有效克服分界面所带来的影响,并能够对大肠杆菌进行实时检测。     

低温等离子体处理对纤维表面的影响

本文介绍了用低温等离子体处理纤维的情况，用低温等离子体处理羊毛纤维引起了 羊毛表面成份和表面结构的某些变化，但不会使基体性质改变。因此增加了处理后的羊 毛纤维的可湿性。改善了染色性能。结果表明，等离子体处理将成为印染工艺的一个新 方法。     

等离子体预处理对镀铜涤纶针刺毡性能的影响

采用射频磁控溅射技术在PET针刺毡表面沉积了纳米结构Cu薄膜,试图利用等离子体预处理的方法来改善薄膜与基材之间的结合牢度。采用扫描电子显微镜(SEM)对低温等离子体预处理前后基材表面形貌的变化进行了分析,同时利用静态液滴形状观察法和接触角测试分析了等离子体处理前后样品的润湿性能。采用X射线能谱仪(EDX)对纳米结构Cu薄膜进行了元素分布及定量分析。结合抗静电性能测试,采用冷热循环试验研究了Ar和O2等离子体预处理对Cu薄膜结合牢度的影响。研究发现,低温等离子体预处理不仅能改善沉积Cu薄膜PET针刺毡的抗静电性能,还能提高膜-基结合牢度和基材的润湿性能。用O2等离子体处理时,膜-基结合牢度和润湿性能较好。     

低温等离子体对铝弹性体表面改性的研究及其应用

铝弹性体表面用低温等离子体处理后 ,极大地提高了铝弹性体与应变片的粘结强度和防潮性能。与未经低温等离子体处理时相比 ,用相同的粘结剂 ,在拉伸试验过程中应变片不脱落的最大应变提高4倍以上 ,绝缘电阻高出一个数量级。此项成果已在金属材料拉伸实验和测力称重传感器中得到应用     

纳米微晶纤维素增强改性聚脲/丙烯酸树脂复合涂膜的性能研究

对纳米微晶纤维素(NCC)增强改性聚脲/丙烯酸树脂(PUA)复合涂膜的性能进行了研究。通过掺入占PUA不同质量分数的NCC来研究其对复合涂膜整体性能的影响。结果表明,随着NCC用量的增大,复合涂膜的拉伸强度先增大后减小。当NCC用量为5%时对涂膜的增强效果最佳,抗拉强度达到12.91 MPa,较未改性的复合涂膜提高了54.98%。而改性复合涂膜的吸水率呈现先减小后增大的趋势,NCC用量为5%左右时吸水率达到最小。5%NCC的加入对复合涂膜的热性能及透光性能影响不大,但改善了复合涂膜的耐高温性能和耐磨性能。     

防静电涂料在纺机上的应用研究

阐述了纺机行业上使用的防静电涂料的选用及表面抗静电涂膜的物化性能,同时提出了纺机行业防静电涂料表面电阻值测试方法及验收标准,现已纳入FZ/T 90074“纺织机械产品涂装”行业标准;对防静电涂料使用后出现的问题提出了处理方法和应对措施,采用抗静电涂料涂覆后,涂膜不仅力学性能特别优越,同时兼备了排除静电荷的功能,而且大大降低了生产成本,获得了良好经济效益,且该涂料对环境友好,提升了市场竞争力。     

Molecular-imprinted, polymer-coated quartz crystal microbalances for the detection of terpenes

A piezoelectric sensor coated with an artificial biomimetic recognition element has been developed for the determination of L-menthol in the liquid phase. A highly specific noncovalently imprinted polymer (MIP) was cast in situ on to the surface of a gold-coated quartz crystal microbalance (QCM) electrode as a thin permeable film. Selective rebinding of the target analyte was observed as a frequency shift quantified by piezoelectric microgravimetry with the QCM. The detectability of L-menthol was 200 ppb with a response range of 0-1.0 ppm. The response of the MIP-QCM to a range of monoterpenes was investigated with the sensor binding menthol in favor of analogous compounds. The sensor was able to distinguish between the D- and L-enantiomers of menthol owing to the enantioselectivity of the imprinted sites. To our knowledge, this is the first report describing enantiomeric resolution within an MIP utilizing a single monomer-functional moiety interaction. It is envisaged that this technique could be employed to determine the concentration of terpenes in the atmosphere.     

Detection of polycyclic aromatic hydrocarbons using quartz crystal microbalances

A chemically coated piezoelectric sensor has been developed for the determination of PAHs in the liquid phase. An organic monolayer attached to the surface of a gold electrode of a quartz crystal microbalance (QCM) via a covalent thiol-gold link complete with an ionically bound recognition element has been produced. This study has employed the PAH derivative 9-anthracene carboxylic acid which, once bound to the alkane thiol, functions as the recognition element. Binding of anthracene via pi-pi interaction has been observed as a frequency shift in the QCM with a detectability of the target analyte of 2 ppb and a response range of 0-50 ppb. The relative response of the sensor altered for different PAHs despite pi-pi interaction being the sole communication between recognition element and analyte. It is envisaged that such a sensor could be employed in the identification of key marker compounds and, as such, give an indication of total PAH flux in the environment.     

Ionic liquids: a new class of sensing materials for detection of organic vapors based on the use of a quartz crystal microbalance

A QCM device employing ionic liquids as the sensing materials for organic vapors has been developed and evaluated. The sensing mechanism is based on the fact that the viscosity of the ionic liquid membrane decreases rapidly due to solubilization of analytes in the ionic liquids. This change in viscosity, which varies with the chemical species of the vapors and the types of ionic liquids, results in a frequency shift of the corresponding quartz crystal. The QCM sensor demonstrated a rapid response (average response time of less than 2 s) to organic vapors with an excellent reversibility because of the fast diffusion of analytes in ionic liquids. Furthermore, the ionic liquids, with zero vapor pressure and stable chemical properties, ensure a long-term shelf life for the sensor.     

Paraoxon imprinted biopolymer based QCM sensor

In this study, a novel quartz crystal microbalance (QCM) based on the modification of paraoxon imprinted polymer (TCM-Cd(II)-paraoxon) film onto a quartz crystal sensor has been developed for the determination of paraoxon. The sensor is based on a molecular imprinted polymer (MIP) which can be synthesized using paraoxon as a template molecule, Thiourea Modified Chitosan-Cd(II) (TCM-Cd(II)) as the metal-chelate monomer, ephychlorohydrin as a crosslinking agent. The MIP particles have been characterized by FTIR measurements and QCM sensor has characterized using AFM and ellipsometer. The performance of the paraoxon imprinted sensor has indicated that a selective and sensitive paraoxon imprinted sensor could be fabricated. The sensor is able to discriminate paraoxon in solution owing to the specific binding of the imprinted sites. The obtained paraoxon imprinted sensor has 0.02–1 μM linear range and low detection limit (0.02 μM). The selectivity studies have shown that the selectivity of prepared paraoxon imprinted sensor has found as being very high in the presence of parathion which is similar in structure with paraoxon. The paraoxon imprinted sensor has been repeatedly used for more than 7 months in many continuous experiments.     

Ligand exchange based paraoxon imprınted QCM sensor

In the present work, a paraoxon imprinted QCM sensor has been developed for the determination of paraoxon based on the modification of paraoxon imprinted film onto a quartz crystal combining the advantages of high selectivity of the piezoelectric microgravimetry using MIP film technique and high sensitivity of QCM detection. The paraoxon selective memories have formed on QCM electrode surface by using a new metal–chelate interaction based on pre-organized monomer and the paraoxon recognition activity of these molecular memories was investigated. Molecular imprinted polymer (MIP) film for the detection of paraoxon was developed and the analytical performance of paraoxon imprinted sensor was studied. The molecular imprinted polymer were characterized by FTIR measurements. Paraoxon imprinted sensor was characterized with AFM and ellipsometer. The study also includes the measurement of binding interaction of paraoxon imprinted quartz crystal microbalance (QCM) sensor, selectivity experiments and analytical performance of QCM electrode. The detection limit and the affinity constant (K_affinity) were found to be 0.06 μM and 2.25 × 10⁴ M^? 1 for paraoxon [MAAP–Cu(II)–paraoxon] based thin film, respectively. Also, it has been observed that the selectivity of the prepared paraoxon imprinted sensor is high compared to a similar chemical structure which is parathion.     

Design and evaluation of an antiparallel coupled resonator for chemical sensor applications

In this paper, a new type of quartz crystal resonator in which the electrodes are located on one side has been developed for chemical sensing. The resonator has two electrodes for exciting thickness shear mode (TSM) vibrations on one side of the crystal and a conductive layer on the other side. These electrodes are capacitively coupled with the electric fields in opposite directions, forming an antiparallel coupled resonator (ACR). The resonant characteristics of the ACR were evaluated as a function of gap width between the two electrodes used to excite the TSM. The conductance value was observed to increase with decreasing gap width. We also discovered that the gap should be parallel with the crystallographic x-axis to obtain the highest sensitivity. The frequency response to a viscous loading was almost same as that of a standard quartz crystal microbalance (QCM). The ACR sensor is an attractive alternative to a QCM chemical sensor because it can be easily integrated into packaging and film coatings.     

Simple low-vacuum coating of paraffin wax on carbonaceous gas sensing layers

A simple low-vacuum coater has been fabricated by using a vacuum resin degassing chamber, in which an aluminum effusion cell is heated by a soldering iron. Our developed vacuum coater presents the versatile methods for depositing paraffin wax for skin-coating the sensing layers of quartz crystal microbalance (QCM). As the increase of the cell temperature, the thickness and inhomogeneity of the wax films were increased. Impedance analyses revealed that the energy dissipation of the QCM was remarkably enhanced with the amount of wax. It was also revealed that the as-deposited wax was fluidic until coagulation by heat radiation. This surface skin coating enhanced the ethyl acetate (EA) sorption capabilities of the polyethylene-sputtered QCM sensor, whereas, it reduced the EA sorption capacity of the d-phenylalanine-sputtered QCM sensor.     

A quartz crystal microbalance-based sensor system coated with functional polymers for SO2 and NO2 detection

In this work, a quartz crystal microbalance (QCM)-based adsorption sensor system with high sensitivity, selectivity, and reproducibility is designed and fabricated. The functional polymers such as polypyrrole, poly(3,4-ethylenedioxythiophene) (PEDOT), and polystyrene are coated on 8 MHz AT-cut quartz crystal surfaces as sensing materials for SO2 and NO2. All sensing materials on the QCM surface are characterized experimentally by SEM and AFM. The frequency shifts of the QCM by adsorption and desorption of gases are measured and analyzed to assess the practical applicability of the sensor system. The overall results show that the QCM coated with polypyrrole is highly selective for SO2 gas and that coated with PEDOT is for NO2. It is proven that the QCM-based adsorption sensor system is possible for monitoring SO2 and NO2 gases in the mixture of ppm level.