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Sensors Journal, IEEE

Issue 9 • Date Sept. 2008

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Displaying Results 1 - 22 of 22
  • [Front cover]

    Publication Year: 2008 , Page(s): C1
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    Freely Available from IEEE
  • IEEE Sensors Journal publication information

    Publication Year: 2008 , Page(s): C2
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  • Table of contents

    Publication Year: 2008 , Page(s): 1497 - 1498
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  • A Resonant Micromachined Electrostatic Charge Sensor

    Publication Year: 2008 , Page(s): 1499 - 1505
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (650 KB) |  | HTML iconHTML  

    A micromachined electrometer, based on the concept of a variable capacitor, has been designed, modeled, fabricated, and tested. The device presented in this paper functions as a modulated variable capacitor, wherein a dc charge to be measured is up-modulated and converted to an ac voltage output, thus improving the signal-to-noise ratio. The device was fabricated in a commercial standard SOI micromachining process without the need for any additional processing steps. The electrometer was tested in both air and vacuum at room temperature. In air, it has a charge-to-voltage conversion gain of 2.06 nV/e, and a measured charge noise floor of 52.4 e/rtHz. To reduce the effects of input leakage current, an electrically isolated capacitor has been introduced between the variable capacitor and input to sensor electronics. Methods to improve the sensitivity and resolution are suggested while the long-term stability of these sensors is modeled and discussed. View full abstract»

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  • Leakage Current Analysis of Nitride-Based Photodetectors by Emission Microscopy Inspection

    Publication Year: 2008 , Page(s): 1506 - 1510
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2013 KB) |  | HTML iconHTML  

    Leakage properties of nitride-based photodetectors (PDs) subjected to inductively coupled plasma (ICP) etching has been investigated by using emission microscopy inspection (EMMI). ICP etching would cause significant damage to GaN metal-semiconductor-metal (MSM) PDs. The damage was proven to induce leakage current via the conductive surface of the device by using emission microscopy inspection. However, the surface damage of MSM PDs could be partially recovered by E-beam SiO2 passivation. As for the passivation for p-i-n photodetectors, the effect was not significant in the reduction of dark current due to smaller etched area as compared to the whole area of p-i-n PDs. The leakage current path analysis of p-i-n PDs by EMMI technique had also been investigated. Finally, the plasma enhanced chemical vapor deposition (PECVD) SiO2 passivation was proven to be a potential process to improve the reliability of p-i-n PDs. View full abstract»

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  • A Monolithic CMOS-MEMS 3-Axis Accelerometer With a Low-Noise, Low-Power Dual-Chopper Amplifier

    Publication Year: 2008 , Page(s): 1511 - 1518
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1899 KB) |  | HTML iconHTML  

    This paper reports a monolithically integrated CMOS-MEMS three-axis capacitive accelerometer with a single proof mass. An improved DRIE post-CMOS MEMS process has been developed, which provides robust single-crystal silicon (SCS) structures in all three axes and greatly reduces undercut of comb fingers. The sensing electrodes are also composed of the thick SCS layer, resulting in high resolution and large sensing capacitance. Due to the high wiring flexibility provided by the fabrication process, fully differential capacitive sensing and common-centroid configurations are realized in all three axes. A low-noise, low- power dual-chopper amplifier is designed for each axis, which consumes only 1 mW power. With 44.5 dB on-chip amplification, the measured sensitivities of x-, y-, and z-axis accelerometers are 520 mV/g, 460 mV/g, and 320 mV/g, respectively, which can be tuned by simply changing the amplitude of the modulation signal. Accordingly, the overall noise floors of the x-, y-, and z-axis are 12 mug/radicHz , 14 mug/radicHz, and 110 mug/radicHz, respectively, when tested at around 200 Hz. View full abstract»

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  • Sensitivity Tuning in Terfenol-D Based Fiber Bragg Grating Magnetic Sensors

    Publication Year: 2008 , Page(s): 1519 - 1520
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (202 KB) |  | HTML iconHTML  

    In this work, the dependence of the magnetostrictive response on the prestress has been used to improve and fit the performance of Terfenol-D based fiber Bragg grating magnetic sensor. The possibility to tune sensitivity allows to work at different operative conditions and to develop advanced sensors with reconfigurable sensitivity. Performance improvements in terms of magnetic resolution up to 0.0116 A/m have been demonstrated. View full abstract»

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  • Ion-Beam Assisted Glancing Angle Deposition for Relative Humidity Sensors

    Publication Year: 2008 , Page(s): 1521 - 1522
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (396 KB) |  | HTML iconHTML  

    Ion-beam assisted glancing-angle deposition is used to fabricate relative humidity sensors. Ion currents of 3,5, and 7 mA were tested. The morphology and capacitance of the sensors are found to be dependent on the ion current density. The capacitance increases with increasing ion current, especially for the 7 mA case which exhibits a capacitance approximately one order of magnitude greater than a standard glancing-angle deposited film over much of the sensor range. View full abstract»

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  • Multiwalled Carbon Nanotubes Modified Electrode as a Sensor for Adsorptive Stripping Voltammetric Determination of Hydrochlorothiazide

    Publication Year: 2008 , Page(s): 1523 - 1529
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (355 KB) |  | HTML iconHTML  

    The study of electrochemical behavior and determination of hydrochlorothiazide, a thiazide diuretic and antihypertensive drug, on multiwalled carbon nanotubes (MCNTs) modified glassy carbon electrode (GCE) is described by adsorptive stripping voltammetry in open circuit potential. The cyclic voltammetric results indicate that MCNTs remarkably enhance the oxidation of hydrochlorothiazide in wide pH range of 2.0-9.5, which is leading to considerable improvement of anodic peak current for hydrochlorothiazide, and allow the development of a highly sensitive voltammetric sensor for determination of hydrochlorothiazide in pharmaceutical and urine samples. Electrochemical studies by alpha-Fe2O3 nanoparticles modified carbon paste electrode show these oxides have no electrocatalytic effect for hydrochlorothiazide oxidation and support iron oxide impurities in the MCNTs are not active sites in sensing of hydrochlorothiazide. Under optimized conditions, the oxidation peak have two linear dynamic range of 2.0-20.0 nM and 0.2-100.0 muM with experimental detection limit of 0.8 nM and a precision of < 4% (RSD for 8 analysis). View full abstract»

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  • Simulation and Fabrication of a Convective Gyroscope

    Publication Year: 2008 , Page(s): 1530 - 1538
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1333 KB) |  | HTML iconHTML  

    In this paper, we present the simulation and fabrication of the gas gyroscope. The gas flow inside the hermetically packed sensor is simulated by utilizing 3-D transient compressible flow analysis. The pump working principle and the effect of the Coriolis acceleration on the laminar jet are validated by both analytical formulas and experiments. The sensor utilizes a new sensing element consisting of a thermistor heated by an interior heater, which is independently power-supplied. The sensor performance can be adjusted by the applied voltage on the heater. Both heater and thermistor are optimized in terms of thermal stress. The effect of thermal stress in a p-type silicon thermistor reduces the performance of sensor by 9.5%. The sensor has been calibrated and the role of the heater is verified. View full abstract»

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  • Sensitive and Selective Photoacoustic Gas Sensor Suitable for High-Volume Manufacturing

    Publication Year: 2008 , Page(s): 1539 - 1545
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1460 KB) |  | HTML iconHTML  

    Sensitive and selective gas measurements are crucial for a large variety of applications. This paper describes the manufacturing and characterization of a photoacoustic gas sensor system. The system is based on a pressure sensor element with a sensitivity of 10 muV/V/Pa. To demonstrate and evaluate the concept, 12 prototypes for measuring CO2 have been manufactured and characterized. Detection limits ranging from 92 ppm to below 6 ppm CO2 were obtained with a path length of 10 cm, depending on the measurement time and photoacoustic cell design. Measurements showed no cross-sensitivity towards CO, CH4, or humidity in any of the sensors. The temperature drift of the uncompensated raw signal of two sensor designs was below 117 ppm CO2 in the range from 25degC to 50degC. View full abstract»

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  • High Sensitivity Plastic-Substrate Photonic Crystal Biosensor

    Publication Year: 2008 , Page(s): 1546 - 1547
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (149 KB) |  | HTML iconHTML  

    A photonic crystal biosensor incorporating a nanomolded porous dielectric is fabricated for the first time on a flexible polysulfone substrate. The plastic substrate necessitates several changes to the fabrication procedure, including reduced processing temperatures. The resulting structure shows excellent response uniformity across a large area in the steady state as well as for perturbations of the bulk and near-surface dielectric permittivity. Kinetic binding data for a representative biomolecular assay demonstrate robust sensor operation. View full abstract»

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  • Compensation of Angular Errors Using Decision Feedback Equalizer Approach

    Publication Year: 2008 , Page(s): 1548 - 1556
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (756 KB) |  | HTML iconHTML  

    Speed and position measurements of rotating shafts are very important in the field of mechanical engineering. In automotive applications, magnetic field sensors for such measurements (camshaft, crankshaft, anti-lock braking system, windshield wiper, etc.) have the largest market share of all sensor types. Camshaft applications are challenging due to their requirements on high angular accuracy under harsh environmental conditions. Due to mounting and packaging tolerances, the magnetic field at the sensors position varies, resulting in angular measurement errors for sensor concepts in use today. Mounting and packaging tolerances cannot be avoided; however, they can be compensated by a new filter structure which is described in this paper. The decision feedback equalizer (DFE) - known from digital communication - was analyzed and modified for the use in angular measurement applications. A new filter structure, using data prediction and an adaptive algorithm based on a physical model, is proposed. This filter calculates and compensates angular errors caused by mounting and packaging tolerances. View full abstract»

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  • Capacitive Transduction for Liquid Crystal Based Sensors, Part II: Partially Disordered System

    Publication Year: 2008 , Page(s): 1557 - 1564
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1352 KB) |  | HTML iconHTML  

    This paper presents the capacitive transduction technique involved with liquid crystal (LC) based sensors in partially disordered systems. These sensors have the potential applications in chemical and biological systems. The theory for tracking the average molecular deformation (state of alignment) and degree of ordering of anisotropic and partially disordered LC film via capacitive sensing is investigated. This system is modeled using the Q-tensor approach in modeling uniaxial LC material. The proposed sensor design is an interdigitated electrodes structure. Transverse and fringing capacitances as function of the molecular deformation are calculated. It is verified that three capacitance measurements are required to track the average molecular orientation and the degree of disorder in the LC film. The sensitivity for the sensor at different alignments and ordering degree is also studied. Toward practical sensor, neuro-fuzzy system is modeled to simulate the capacitive transduction and to monitor the LC profile. Sensors are fabricated and tested. Both the experimental and calculated capacitances are presented and compared. View full abstract»

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  • A Potentiometric \hbox {CO}_{2} Sensor Combined With Composite Metal Oxide and DOP Plasticizer Operative at Low Temperature

    Publication Year: 2008 , Page(s): 1565 - 1570
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (917 KB) |  | HTML iconHTML  

    A low-temperature lithium ion based potentiometric CO2 sensor has been developed by adding 10 mol% of SiO2, B2O3, Li2O, and Bi2O3 composite metal oxide mixture to (Li2-Ba)CO3 sensing bicarbonate. The sensors added with different mol% of oxides were tested at different operating temperatures. The sensor with 1:2:1:1 mol% of the SiO2:B2O3:Li2O:Bi2O3 composite metal oxide showed a fair Nernstian correlation and obtained n value equal to 2 at 300degC, where n is the number of reaction electrons. A glassy sensing phase resulted that improved response and recovery. The sensor is also found stable against humidity (70% RH) at 300 degC. However, it is further observed that the performance of the sensor deteriorated with increasing Li2O or decreasing B2O3 content. The sensor performance could further be improved at lower temperatures with the introduction of dioctyl phthalate (DOP) plasticizer into the sensing electrode. View full abstract»

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  • Development of a Disposable All-Solid-State Ascorbic Acid Biosensor and Miniaturized Reference Electrode Fabricated on Single Substrate

    Publication Year: 2008 , Page(s): 1571 - 1577
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (560 KB) |  | HTML iconHTML  

    A low-cost, small-size, and all-solid-state biosensor for the specific determination of L-ascorbic acid was developed. The sensor array was fabricated by screen printing, and the ruthenium oxide (RUO2) thin film was deposited on the working area of each sensor by an RF sputtering method for surface modification. A conductive polymer (polypyrrole) miniaturized reference electrode was used in combination with the biosensor. The ascorbate oxidase was immobilized with 3-glycidoxypropyltrimethoxysilane (GPTS) methods in the bioactive membrane layer. In accordance with experiment results, the sensor has the better average sensitivity of 51.85 mV/pH between pH 1 and pH 13. The investigated characteristics in the polypyrrole film modified reference electrode show a very small drift voltage (5 mV/h) and the standard deviation of the reference electrode is 1.093 mV. According to the experiment results, the potential response of the enzyme-based biosensor depends linearly on L-ascorbic acid concentration between 0.02 mM and 1 mM with a linear correlation coefficient of 0.86 and the sensitivity is 13.85 mV/mM. View full abstract»

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  • Bio-Assessing of Environmental Pollution via Monitoring of Metallothionein Level Using Electrochemical Detection

    Publication Year: 2008 , Page(s): 1578 - 1585
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB) |  | HTML iconHTML  

    In this paper, we report on an investigation of affecting guppy fishes (Poecilia reticulata) by silver ions (0, 0.3, 0.6, 1.2, 2.5, and 5 muM) for seven days under well-controlled experimental conditions. To observe the physiological changes, we attempted to determine metallothionein (MT) as a biomarker of heavy metal stress. For this purpose, we proposed a sensor utilizing a carbon electrode coupled with flow injection analysis. The experimental conditions, which have been optimized, were as follows-applied potential: 750 mV, mobile phase: Britton-Robinson buffer (pH 1.9) with flow rate of 0.6 ml/min, time filter: 2.5 s, "current R": 1 muA. Under these conditions, the detection limit of MT was estimated as 100 pM. After the optimizing step, the fish tissues were measured. Based on the results obtained, MT content increased with increasing dose of silver ions and time of the treatment. The results obtained were in good correlation with those obtained by adsorptive transfer stripping technique coupled with differential pulse voltammetry Brdicka reaction, which was used as the reference technique. View full abstract»

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  • Differentiation of Proteins and Viruses Using Pyrolysis Gas Chromatography Differential Mobility Spectrometry (PY/GC/DMS) and Pattern Recognition

    Publication Year: 2008 , Page(s): 1586 - 1592
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (621 KB) |  | HTML iconHTML  

    It is extremely important to develop novel analytical sensors for pathogen detection. Applications of such sensors range from ensuring environmental monitoring, to providing human health diagnostic measures, and to early warning systems for bioterrorism. Certain viruses and bacteria pathogens are of special concern for their ability to spread rapidly in human populations during a pandemic, and emerging variants of these pathogens are challenging to detect. This paper provides a reliable detection strategy to classify viruses from innocuous proteins. Our novel instrumentation is based on pyrolysis gas chromatography differential mobility spectrometry (PY/GC/DMS), and couples a genetic algorithm based machine learning method for pattern recognition with a microfabricated solid state biosensor. Together, this hardware and software combination allowed for an extremely high classification accuracy (94%) between the T4 bacteriophage from bovine serum albumin (BSA), an unrelated protein. This study suggests that this portable sensor can be used along with the sophisticated data mining method as a fast, reliable, and accurate tool for the recognition of viruses. View full abstract»

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  • Conductivity-Based Catechol Sensor Using Tyrosinase Immobilized in Porous Silicon

    Publication Year: 2008 , Page(s): 1593 - 1597
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (687 KB) |  | HTML iconHTML  

    A conductivity-based catechol biosensor was developed using porous silicon as an immobilization matrix for enzyme tyrosinase. The enzyme was extracted from plant source Amorphophallus companulatus and immobilized in an electrochemically etched surface of p-type silicon. The presence of enzyme in a porous structure and the retention of enzyme activity were confirmed by scanning electron microscopy and spectrophotometric studies, respectively. The principle of the sensor is based on the change in the conductivity of the tyrosinase-entrapped porous silicon matrix. When the entrapped tyrosinase interacted with catechol, the change in the current voltage (I-V) characteristics was obtained, which was proportional to analyte concentration. The analytical characteristics of the sensor including response time, linearity range, lower detection limit, reusability, and storage stability were studied. View full abstract»

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  • A Novel Fiber Bragg Grating Sensor Configuration for Long-Distance Quasi-Distributed Measurement

    Publication Year: 2008 , Page(s): 1598 - 1602
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (603 KB) |  | HTML iconHTML  

    A novel fiber Bragg grating (FBG) sensor configuration using three broadband light sources of different wavelength bands for the interrogation of FBG sensors distributed over 75 km of fiber is proposed and demonstrated. Rayleigh backscattering was reduced and a 60-dB effective dynamic range was demonstrated. View full abstract»

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  • Design of Bragg Grating Sensors Based on Submicrometer Optical Rib Waveguides in SOI

    Publication Year: 2008 , Page(s): 1603 - 1611
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (997 KB) |  | HTML iconHTML  

    A submicrometer integrated optical sensor based on Bragg gratings in silicon-on-insulator technology is theoretically proposed in this paper. The grating analysis is performed using a mixed numerical approach based on the finite-element method and coupled mode theory. The possibility to use third-order instead of first-order grating is discussed and performances compared, thus overcoming fabrication problems associated to submicrometer scale features. A detection limit of approximately 10-4 refractive index unit has been calculated for a 173-mum-long grating. Strategies to further improve this value have been discussed too. Finally, fabrication tolerances influence on optimized gratings has been investigated. View full abstract»

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  • IEEE Sensors Council Information

    Publication Year: 2008 , Page(s): C3
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    Freely Available from IEEE

Aims & Scope

The IEEE Sensors Journal is a peer-reviewed, monthly online/print  journal devoted to sensors and sensing phenomena

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Editor-in-Chief
Krikor Ozanyan
University of Manchester
Manchester, M13 9PL, U.K.