Quartz Sensor Research Articles

Determination of Daminozide in Apple Sample by Mip‐Coated Piezoelectric Quartz Sensor

A piezoelectric crystal sensor has been prepared by using a molecularly imprinted polymer as recognition element. A typical time‐response curve of the molecularly imprinted polymer (MIP)‐coated crystal to the daminozide (DM) solution has been described. Frequency shifts versus logarithm changes of DM showed good linear correlation within the concentration range of 1.0×10−9–10−6 mg ml−1 (y=11.38x+ 115.45, r=0.9872) and 1.0×10−6–10−1 mg ml−1 (y=25.22x+209.44, r=0.9938), respectively. The detection limit was 5.0×10−8 mg ml−1 (S/N=3). The obtained sensor has high sensitivity and selectivity, low cost, good reproducibility, and reusable property by combining with piezoelectric crystal and molecularly imprinted polymer.

水晶振動子計測によるプラズマ気相成分分析

Our partial pressure measurement for a binary gas with a quartz sensor can be applied to plasmas. In this study, the Q-sensor outputs, which depend on pressure, molecular weight and viscosity of gases, were compared to the results by gas analysis with a quadrupole mass spectrometer (QMS). For H2 plasmas, the Q-sensor outputs changed when discharges were turned on and off. On the other hand, the results from mass spectroscopy by the QMS showed the degas of carbon monoxide (CO) during the discharges. Since the changes of the Q-sensor outputs correspond to the CO production above, it can be concluded that the Q-sensor measurements can detect the gas composition changes in the plasmas, thereby, can be used as a simple gas analysis method compared to a conventional mass spectrometer.

Vacuum sealed surface acoustic wave pressure sensor

A vacuum sealed SAW pressure sensor is disclosed herein, which includes a sensing element configured as a SAW device (e.g. SAW resonator or SAW delay line) supported by a thin diaphragm. The substrate material can be implemented as a quartz wafer (i.e., “base” wafer). The SAW device can be configured on one side of the wafer and the diaphragm etched on the opposite side. A quartz micromachined pressure sensor can thus be realized, which operates based on a variation of the surface wave velocity of a SAW device situated on the thin diaphragm. The SAW sensor is generally sealed in a vacuum and diaphragm sustains the sensor, thereby implementing a sensor on a wafer scale while allowing for a cost reduction per chip.

Novel Applications of the QCM Technique in Biomaterials Science

ABSTRACTA quartz crystal microbalance (QCM) has been used to investigate polymer samples. The vapor sorption of three different polymer samples (poly(vinyl acetate), polybutadiene and polydimethylsiloxane) was studied. The change in resonance frequency of the quartz sensor uniformly coated with polymer films was measured as a function of the film thickness and water absorption at different temperatures. The range of linear frequency vs. mass response was determined in the absence of absorbed water. The glass transition temperature of thin poly(vinyl acetate) films (10 nm <thickness< 1000 nm) was found to be in reasonable agreement with published values for macroscopic samples.

Encapsulated surface acoustic wave sensor

Sensor package systems and methods are disclosed, which include a quartz sensor package encapsulated by an overmold material. A surface acoustic wave sensing element and one or more bonding pads can be integrated with the quartz sensor package. Additionally, one or more antennas can be respectively bonded to the quartz sensor package at the bonding pads, such that the antennas communicates electrically with the surface acoustic wave sensing element and permits wireless interrogation of the quartz sensor package including the surface acoustic wave sensing element from an external wireless source.

Interface circuits for quartz crystal sensors in scanning probe microscopy applications

Complementary to industrial cantilever based force sensors in scanning probe microscopy (SPM), symmetrical quartz crystal resonators (QCRs), e.g., tuning fork, trident tuning fork, and needle quartz sensors, are of great interest. A self-excitation scheme with QCR is particularly promising and allows the development of cheap SPM heads with excellent characteristics. We have developed a high performance electronic interface based on an amplitude controlled oscillator and a phase-locked loop frequency demodulator applicable for QCR with frequencies from 10 up to 10MHz. The oscillation amplitude of the sensing tip can be set from thermal noise level up to amplitudes of a tenth of nanometers. The device is small, cheap, and highly sensitive in amplitude and frequency measurements. Important features of the design are grounded QCR, parasitic capacity compensation, bridge schematic, and high temperature stability. Characteristic experimental data of the device and its operation in combination with a commercial SPM and a homemade scanning near-field optical microscope are reported. By using the 1MHz needle quartz resonator with a standard atomic force microscope tip attached, atomic scale resolution in ambient conditions is achieved. Furthermore, reproducible measurements on very soft materials (Langmuir-Blodgett layers) with a very stiff needle quartz (∼400000N∕m) are possible.

Detection of Folate Binding Protein with Enhanced Sensitivity Using a Functionalized Quartz Crystal Microbalance Sensor

In this report, we describe the development of a quartz crystal microbalance biosensor for detection of folate binding protein (FBP). Using a simple folate-BSA conjugate adsorbed onto a Au-coated quartz sensor, a detection limit of 30 nM was achieved. Binding of FBP to the sensor surface could be blocked at concentrations as high as 1 microM with a 100-fold excess of folic acid, indicating the specificity of the folate-FBP interaction and the absence of nonspecific binding to the functionalized surface. Moreover, capture could be achieved in the presence of blood serum, making the assay amenable to the analysis of bodily fluids. Further signal enhancement based on an anti-FBP antibody and protein-A-coated gold nanosphere sandwich assay extended the detection limit to 50 pM (approximately 3 orders-of-magnitude improvement). Given the overexpression of FBP in certain malignancies and inflammatory disorders, we expect the methodology described here to be useful to detect FBP as a possible biomarker for disease diagnosis.

Laser ultrasonic analysis of normal modes generated by a voltage pulse on an AT quartz sensor

Laser ultrasonic detection is a versatile and highly sensitive tool for the observation of surface waves. In the following study, laser ultrasonic detection is used for the experimental study of spurious normal vibration modes of a disk quartz sensor excited by a voltage pulse. The AT cut crystal (cut of the crystal relative to the the main crystallographic axis is 35.25°) is optimal for generating mainly thickness–shear vibrations (central frequency 6 MHz) on the quartz surface. However, resulting from shear-to-longitudinal and shear-to-surface mode conversion, and from the weak coupling with the other crystallographic axes, other modes (thickness-compressional and bending modes) are always present in the plate response. Since the laser vibrometer is sensitive to normal displacements, the laser investigation shows waves that can be considered as unwanted for the AT quartz used as a shear sensor. The scanned three dimensional (3D) amplitude–space–time signals are carefully analysed using their representation in three dual Fourier domains (space–time, wave number–frequency). Results on the transient analysis of the waves, the normal bending modes and the dispersion curves are shown.

Principle and manufacture of a new type of torque sensor based on the torsional effect of a piezoelectric quartz disc

This paper mainly investigates the theoretical foundation of a new-type torque sensor (namely, the torsional effect of a piezoelectric quartz disc), the design and calibration of the torque sensor and its engineering application. By using the theory of anisotropic elasticity and Maxwell electromagnetism, the torsion stress and the distribution of bound volume and surface charge densities of a piezoelectric quartz disc are calculated, and then by the finite element method the polarized electric field is simulated. The results show that the distributions of the potential and the electric field intensity in the quartz disc are both antisymmetric with respect to the y-axis. Based on the torsional effect, a new type of torque sensor is designed. The outstanding feature of the torque sensor, in contrast to other types of quartz torque sensor, is that the torque sensor adopts a torsional effect, rather than a shear effect. Only three Y0°-cut discs are used in the torsion quartz measuring cell of the torque sensor. After static and dynamic calibrations, the torque sensor has fully reached the dynamometer standard stipulated by CIRP-STCC. Finally, a drilling experiment is performed to test the application performance of the torque sensor. The experimental results prove that the theoretical analyses and design of the torque sensor are rational. The new type of torque sensor is the subject of an application for a Chinese Invention Patent, Application Number: 03133521.7.

Evaluation of Quartz Piezoelectric Weigh-in-Motion Sensors

Quartz piezoelectric weigh-in-motion (WIM) sensors are potentially appealing because of their low sensitivity to temperature fluctuations, according to information gathered from previous installations in other states. These installations also called into question the durability of the quartz sensors. Some sensors stopped producing a signal even though the sensor installation did not exhibit physical distress. After design changes were made, it was necessary to reevaluate the quartz sensor before any major investment in this technology in Texas. This research was undertaken to evaluate the performance and durability of quartz piezoelectric WIM sensors. To perform this evaluation, researchers instrumented two sites with quartz sensors and collected truck weight and sensor condition data to analyze the accuracy and durability of these sensors. The results of this research show that the sensors meet or exceed the weight accuracy specified by the ASTM specification for Type 1 highway WIM systems. The data further show that the truck weights produced by the WIM system are stable over time with minimal variation due to temperature change. There have been no sensor failures or degradation of the installations to date.

Evaluation of Quartz Piezoelectric Weigh-in-Motion Sensors

Quartz piezoelectric weigh-in-motion (WIM) sensors are potentially appealing because of their low sensitivity to temperature fluctuations, according to information gathered from previous installations in other states. These installations also called into question the durability of the quartz sensors. Some sensors stopped producing a signal even though the sensor installation did not exhibit physical distress. After design changes were made, it was necessary to reevaluate the quartz sensor before any major investment in this technology in Texas. This research was undertaken to evaluate the performance and durability of quartz piezoelectric WIM sensors. To perform this evaluation, researchers instrumented two sites with quartz sensors and collected truck weight and sensor condition data to analyze the accuracy and durability of these sensors. The results of this research show that the sensors meet or exceed the weight accuracy specified by the ASTM specification for Type 1 highway WIM systems. The data further show that the truck weights produced by the WIM system are stable over time with minimal variation due to temperature change. There have been no sensor failures or degradation of the installations to date.

The Effect of Secondary Piezoelectric Effect on the Measuring Precision of Quartz Dynamometers

People apply quartz dynamometers to measure of milling force extensively. It is mainly made from piezoelectric quartz sensor. In this paper, the theory of the secondary piezoelectric effect is deduced by four kinds of piezoelectric equations. With the measuring the quartz stack secondary piezoelectric effect is verified. By theory and experiment we can show that the secondary piezoelectric effect makes elastic compliance constant of piezoelectric quartz smaller and do elastic stiffness constant of piezoelectric quartz bigger. Obviously, the secondary piezoelectric effect will have direct effect on the measuring precision of quartz dynamometers. So the investigations of secondary piezoelectric effect contribute to improving measuring precision of piezoelectric dynamometers.

CMP시 SiO2슬러리의 마찰 특성과 연마결과에 관한 연구

The effects of mechanical parameters on the characteristics of chemical mechanical polishing(CMP) can be directly evaluated by friction force. The piezoelectric quartz sensor for friction force measurement was installed, and friction force could be detected during CMP process. Furthermore. friction energy can be calculated by multiplying relative velocity by integration of the friction force throughout the polishing time. Si02 slurry for interlayer dielectric(ILD) CMP was used in this experiment to consider the relation of frictional characteristics and polishing results. From. this experiment, it is proven that the friction energy is an essential factor of removal rate. Also, the friction force is related to removal amount per unit length(dH/ds) and friction energy has corelation to the removal rate(dH/dt) and process temperature. Moreover, within wafer non-unifornity(WIWNU) is related to coefficient of friction because of the mechanical moment equilibrium. Therefore, the prediction of polishing result would be possible by measuring friction force.

Application of Artificial Neural Networks in Multitouch- Sensitive Systems for the Detection of Nitrohydrocarbons in the Air

Artificial neural networks (ANN) were applied for use with electronic-nosegenerated analytical signals. The use of ANN as a sensor calibration means was evaluated.Piezoelectric quartz sensors array in addition to the ANN data allow recognition of aliphaticnitrohydrocarbons С1–С3.

Piezoelectric quartz sensor for caffeine based on molecularly imprinted polymethacrylic acid

The feasibility of a piezoelectric quartz caffeine sensor based on a molecularly imprinted poly methacrylic acid is described. The caffeine sensor was devised by depositing the polymer onto one side of an AT-cut quartz crystal through an electropolymerization process The sensor response exhibited a linear relationship between frequency shift and the logarithm of the caffeine concentration in the range of 1 × 10 −9 up to 1 mg/mL. The sensor showed a sensitivity of about 53 Hz/ln (conc., mg/mL) and a limit of detection of 5.9 × 10 −11 mg/mL. The performance of the sensor was affected by parameters such as the nature of the immobilizing agents, the polymer load, the thickness of the coating and the pH. Surface analysis techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were performed on the sensor surface to establish the imprinting of the caffeine molecule. The SEM micrographs, AFM image and XPS spectra provided evidences for the imprinting process and the recognition of caffeine by the MIP during the sensing process.

Measurement of the Osmotic Properties of Thin Polymer Films and Biological Tissue Samples

A new type of micro-osmometer is described in which water absorption of small tissue samples is measured by a quartz crystal microbalance (QCM). The swelling of the sample deposited on the surface of a quartz crystal is determined by monitoring the change in resonance frequency of the quartz sensor as a function of the vapor pressure in the surrounding environment. The measurement principle is verified by studying the water uptake of poly(vinyl alcohol) films. Reasonable agreement is found between the results obtained by the QCM-based osmometer and previous osmotic pressure measurements made on a similar poly(vinyl alcohol) sample. The feasibility of the new method is demonstrated by measuring the osmotic response of tissue-engineered cartilage samples. It is found that the osmotic pressure of cartilage substantially increases with culture time. The present result is consistent with cartilage models, suggesting that the proteoglycan content governs the compressive resistance of the tissue.

Preparation and Characterization of Thin Films by Pulsed Laser Deposition for NOx gas Sensor

ABSTRACTGas sensors based on WO3 thin films doped with platinum (Pt) or palladium (Pd) were prepared by KrF excimer pulsed laser deposition method combined with dc sputtering. The films were deposited on silicon, quartz and Al2O3 sensor substrate with Pt interdigital electrodes at various substrate temperatures from 300°C to 500 °C, and oxygen pressures from 100 mTorr to 300 m Torr, respectively during the deposition. The morphology and structure of the films were examined by AFM and XRD. The sensor property of the WO3−x thin films was measured by the two terminal resistance method at operating temperatures of 25 °C to 400 °C. The sensitivity of the WO3 thin film gas sensors with doping (platinum or palladium) was found to be higher than that of undoped WO3 thin films gas sensors. The sensitivity of the pt doped WO3 films to different concentration of NO gas was examined and the sensitivity was found to be increased with increasing NO gas concentration.

Quartz crystal microbalance-with dissipation monitoring (QCM-D) for real time measurements of blood coagulation density and immune complement activation on artificial surfaces

A recently developed variant of quartz crystal microbalance (QCM) called QCM-with dissipation monitoring (QCM-D) allows simultaneous and simple measurements of changes in adsorbed mass as well as the viscoelastic property (D-factor) of deposited protein layers on the sensor surface. We have taken the QCM-D technology a step further and demonstrated its advantages in the study of protein assembly as a consequence of surface induced immune complement activation, or contact activated blood coagulation. In the present study we have continued our QCM-D investigations of surface assembly of fibrin clot formation and complement activation and incubated differently modified quartz sensor surfaces in blood plasma and sera. Polymer surfaces used were spin-coated polyethylene, poly(ethylene terephtalate), poly(methylmetacrylate) and poly(dimethylsiloxane). Also used were sputtered titanium and heparin grafted surfaces. In this investigation we found that we could describe the surface induced coagulation with four independent parameters: (1) Time of onset of coagulation, (2) fibrin deposition rate, (3) total frequency shift at stable plateau, and (4) fibrin clot density. The most important finding was that the blood plasma clot density can be assessed with the use of D determinations and that the clot density varied significantly with the chemical composition of the surface. However, the D-factor did not give any new analytical information about the possible complement activation mechanisms. Nevertheless, the QCM-D was found to be a reliable tool for the analysis of surface induced complement activation. We also compared the QCM-D technique with traditional enzyme immuno assay (EIA) measurements of soluble products from the surface activation of the complement and coagulation systems. We found that the results from EIA and QCM-D measurements corresponded well for the complement activation but not for the coagulation, probably due to the biological complexity of the coagulation system.

Cell Attachment and Spreading Processes Monitored by the Thickness Shear-Mode Quartz Sensor

Kinetics of attachment and spreading processes of adherent living cells are investigated using the thickness shear-mode quartz-crystal sensor technique. Within the framework of the transmission line representation and its variant the lumped element model, experimental results of the shear electrical motional resistance derived from the Butterworth-Van Dyke equivalent circuit in the vicinity of the sensor mechanical resonant frequency have shown that the increase of this parameter is strongly correlated with the evolving surface coverage during attachment and spreading of the adherent living cells on the quartz sensor surface. Both the dependence of the shear electrical motional resistance on the cell concentration and the contribution of the extracellular matrix proteins on the shear acoustical response of the thickness shear-mode quartz sensor are analyzed. Shear acoustical results are further correlated to both optical microscopic observation and cell counting technique. Finally, the ability of the thickness shear-mode quartz resonator technique to monitor specific cell-substrate interactions is discussed.

CMP 결과에 영향을 미치는 마찰 특성에 관한 연구

Chemical mechanical polishing (CMP) process was studied in terms of tribology in this paper. CMP performed by the down force and the relative motion of pad and wafer with slurry is typically tribological system composed of friction, wear and lubrication. The piezoelectric quartz sensor for friction force measurement was installed and the friction force was detected during CMP process. Various friction signals were attained and analyzed with the kind of pad, abrasive and abrasive concentration. As a result of experiment, the lubrication regime is classified with ηv/p(η, v and p; the viscosity, relative velocity and pressure). The characteristics of friction and material removal mechanism is also different as a function of the kind of abrasive and the abrasive concentration in slurry. Especially, the material removal per unit distance is directly proportional to the friction force and the non~uniformity has relation to the coefficient of friction.