The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform

Jin Xie - One of the best experts on this subject based on the ideXlab platform.

  • Airborne particulate matter classification and concentration detection based on 3D printed virtual impactor and quartz crystal microbalance Sensor
    Sensors and Actuators A-physical, 2016
    Co-Authors: Jiuxuan Zhao, Minliang Liu, Liang Liang, Wen Wang, Jin Xie
    Abstract:

    Abstract In this paper, design, fabrication and experiment of a miniature system for detection of airborne particulate matter (PM) are presented. The miniature system contains a virtual impactor and a quartz crystal microbalance (QCM) Resonant Sensor. The virtual impactor is fabricated by three-dimensional (3D) printing process for classifying airborne particles according to their size. The QCM Resonant Sensor is utilized to detect the mass of the separated particles from the virtual impactor. The design of virtual impactor is optimized by computational fluid dynamics simulation and the QCM for its resonance in thickness shear mode is analyzed by finite element method. Silicon dioxide powders with diameter in the range from 0.5 to 8 μm are successfully separated according to their size by the virtual impactor, which indicates that the classification characteristic coincides with the theoretical and simulation results. PM concentration in a chamber is measured by the proposed monitoring system and the experimental results show that the Resonant frequency of the QCM turns downward linearly with the PM mass loading increasing.

  • Airborne particulate matter classification and concentration detection based on 3D printed virtual impactor and quartz crystal microbalance Sensor
    2016 IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS), 2016
    Co-Authors: Jiuxuan Zhao, Minliang Liu, Wen Wang, Jin Xie
    Abstract:

    This paper reports a miniature system for detection of airborne particulate matter (PM), which contains a virtual impactor and a quartz crystal microbalance (QCM) Resonant Sensor. Silicon dioxide powders with diameter in the range from 0.5 to 8 μm are successfully separated by the virtual impactor according to their size. PM concentration in a chamber is measured by the proposed monitoring system and the experimental results show that the Resonant frequency of the QCM turns downward linearly with the PM mass loading increasing. The proposed monitoring system can complete measurement of PM concentration of 35 μg/m3 in only 23 seconds.

Hyunjoo Lee - One of the best experts on this subject based on the ideXlab platform.

  • a capacitive micromachined ultrasonic transducer based Resonant Sensor array for portable volatile organic compound detection with wireless systems
    Sensors, 2019
    Co-Authors: Inug Yoon, Gayoung Eom, Sungwoo Lee, Bo Kyeong Kim, Sang Kyung Kim, Hyunjoo Lee
    Abstract:

    The development of portable volatile organic compound (VOC) Sensors is essential for home healthcare and workplace safety because VOCs are environmental pollutants that may critically affect human health. Here, we report a compact and portable Sensor platform based on a capacitive micromachined ultrasonic transducer (CMUT) array offering multiplex detection of various VOCs (toluene, acetone, ethanol, and methanol) using a single read-out system. Three CMUT Resonant devices were functionalized with three different layers: (1) phenyl-selective peptide, (2) colloids of single-walled nanotubes and peptide, and (3) poly(styrene-co-allyl alcohol). As each device exhibited different sensitivities to the four VOCs, we performed principal component analysis to achieve selective detection of all four gases. For the simultaneous detection of VOCs using CMUT Sensors, the changes in the Resonant frequencies of three devices were monitored in real time, but using only a single oscillator through an electrically controlled relay to achieve compactness. In addition, by devising a wireless system, measurement results were transmitted to a smartphone to monitor the concentration of VOCs. We used multiple Sensors to obtain a larger number of fingerprints for pattern recognition to enhance selectivity but interfaced these Sensors with a single read-out circuit to minimize the footprint of the overall system. The compact CMUT-based Sensor array based on a multiplex detection scheme is a promising Sensor platform for portable VOC monitoring.

  • mesoporous thin film on highly sensitive Resonant chemical Sensor for relative humidity and co2 detection
    Analytical Chemistry, 2012
    Co-Authors: Hyunjoo Lee, Kwan Kyu Park, Mario Kupnik, Nicholas A Melosh, B T Khuriyakub
    Abstract:

    Distributed sensing of gas-phase chemicals is a promising application for mesoporous materials when combined with highly sensitive miniaturized gas Sensors. We present a direct application of a mesoporous silica thin film on a highly sensitive miniaturized Resonant chemical Sensor with a mass sensitivity at the zeptogram scale for relative humidity and CO2 detection. Using mesoporous silica thin-film, we report one of the lowest volume resolutions and a sensitive detection of 5.1 × 10–4% RH/Hz to water vapor in N2, which is 70 times higher than a device with a nontemplated silica layer. In addition, a mesoporous thin-film that is functionalized with an amino-group is directly applied on the Resonant Sensor, which exhibits a volume sensitivity of 1.6 × 10–4%/Hz and a volume resolution of 1.82 × 10–4% to CO2 in N2.

  • zero bias Resonant Sensor with an oxide nitride layer as charge trap
    IEEE Sensors, 2010
    Co-Authors: Kwan Kyu Park, Hyunjoo Lee, Mario Kupnik, Omer Oralkan, B T Khuriyakub
    Abstract:

    We report on a capacitive Resonant Sensor with an oxide-nitride (ON) layer used as charge trap. The main idea is that we intentionally inject charges into the ON layer by biasing the device for 30 s with 160% of the pull-in voltage. We use a capacitive micromachined ultrasonic transducer (CMUT) to demonstrate this idea. The CMUT is fabricated via high temperature assisted direct wafer bonding after a local oxidation of silicon (LOCOS) to form evacuated cavities (vacuum gaps), and, thus, the device inherently has the ON layer beneath single-crystal silicon plates and vacuum gaps. Therefore, this device is ideal for this work. It allows us to test an elegant charge injection mechanism. By simply pulling in the plate a high electric field strength (∼ 8.9 MV/cm) is created in the ON layer for a designated time, which results in charge injection. These charges stay trapped in the ON layer and create an intrinsic electric field in the vacuum gaps, which would otherwise require an external dc bias voltage of 44% of the pull-in voltage. We successfully implemented a 5.3-MHz oscillator with this zero-bias resonator and achieved excellent noise performance of 0.06 Hz of Allan deviation.

  • highly sensitive detection of dmmp using a cmut based chemical Sensor
    IEEE Sensors, 2010
    Co-Authors: Hyunjoo Lee, Kwan Kyu Park, Mario Kupnik, Omer Oralkan, B T Khuriyakub
    Abstract:

    We present ppt-level detection of dimethyl methylphosphonate (DMMP), a common simulant used in detector calibrations for sarin gas, using a new capacitive micromachined ultrasonic transducer (CMUT) design with a mass sensitivity improved from 130 zg/Hz/µm2 to 48.8 zg/Hz/µm2. A low-noise oscillator using the CMUT as the frequency selective component exhibits an Allan deviation of 0.55 Hz at the presence of air flow. The CMUT Resonant Sensor was functionalized with a 50-nm thick proprietary polymer layer (Sandia National Laboratory, Albuquerque, NM). Our Sensor performance was reliably measured at the MIT Lincoln Laboratory where the accurate delivery of low concentrations of gases was ensured through stringent calibrations. Our Sensor response to various concentrations of DMMP in air (10 ppb-1 ppm) showed an excellent volume sensitivity of 30.6 pptv/Hz. Based on the system noise floor, we achieved a mass resolution of 26.9 zg/µm2 and a limit of detection of 16.8 pptv. In addition, the Sensor showed good selectivity to DMMP.

Jiuxuan Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Airborne particulate matter classification and concentration detection based on 3D printed virtual impactor and quartz crystal microbalance Sensor
    Sensors and Actuators A-physical, 2016
    Co-Authors: Jiuxuan Zhao, Minliang Liu, Liang Liang, Wen Wang, Jin Xie
    Abstract:

    Abstract In this paper, design, fabrication and experiment of a miniature system for detection of airborne particulate matter (PM) are presented. The miniature system contains a virtual impactor and a quartz crystal microbalance (QCM) Resonant Sensor. The virtual impactor is fabricated by three-dimensional (3D) printing process for classifying airborne particles according to their size. The QCM Resonant Sensor is utilized to detect the mass of the separated particles from the virtual impactor. The design of virtual impactor is optimized by computational fluid dynamics simulation and the QCM for its resonance in thickness shear mode is analyzed by finite element method. Silicon dioxide powders with diameter in the range from 0.5 to 8 μm are successfully separated according to their size by the virtual impactor, which indicates that the classification characteristic coincides with the theoretical and simulation results. PM concentration in a chamber is measured by the proposed monitoring system and the experimental results show that the Resonant frequency of the QCM turns downward linearly with the PM mass loading increasing.

  • Airborne particulate matter classification and concentration detection based on 3D printed virtual impactor and quartz crystal microbalance Sensor
    2016 IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS), 2016
    Co-Authors: Jiuxuan Zhao, Minliang Liu, Wen Wang, Jin Xie
    Abstract:

    This paper reports a miniature system for detection of airborne particulate matter (PM), which contains a virtual impactor and a quartz crystal microbalance (QCM) Resonant Sensor. Silicon dioxide powders with diameter in the range from 0.5 to 8 μm are successfully separated by the virtual impactor according to their size. PM concentration in a chamber is measured by the proposed monitoring system and the experimental results show that the Resonant frequency of the QCM turns downward linearly with the PM mass loading increasing. The proposed monitoring system can complete measurement of PM concentration of 35 μg/m3 in only 23 seconds.

B T Khuriyakub - One of the best experts on this subject based on the ideXlab platform.

  • mesoporous thin film on highly sensitive Resonant chemical Sensor for relative humidity and co2 detection
    Analytical Chemistry, 2012
    Co-Authors: Hyunjoo Lee, Kwan Kyu Park, Mario Kupnik, Nicholas A Melosh, B T Khuriyakub
    Abstract:

    Distributed sensing of gas-phase chemicals is a promising application for mesoporous materials when combined with highly sensitive miniaturized gas Sensors. We present a direct application of a mesoporous silica thin film on a highly sensitive miniaturized Resonant chemical Sensor with a mass sensitivity at the zeptogram scale for relative humidity and CO2 detection. Using mesoporous silica thin-film, we report one of the lowest volume resolutions and a sensitive detection of 5.1 × 10–4% RH/Hz to water vapor in N2, which is 70 times higher than a device with a nontemplated silica layer. In addition, a mesoporous thin-film that is functionalized with an amino-group is directly applied on the Resonant Sensor, which exhibits a volume sensitivity of 1.6 × 10–4%/Hz and a volume resolution of 1.82 × 10–4% to CO2 in N2.

  • zero bias Resonant Sensor with an oxide nitride layer as charge trap
    IEEE Sensors, 2010
    Co-Authors: Kwan Kyu Park, Hyunjoo Lee, Mario Kupnik, Omer Oralkan, B T Khuriyakub
    Abstract:

    We report on a capacitive Resonant Sensor with an oxide-nitride (ON) layer used as charge trap. The main idea is that we intentionally inject charges into the ON layer by biasing the device for 30 s with 160% of the pull-in voltage. We use a capacitive micromachined ultrasonic transducer (CMUT) to demonstrate this idea. The CMUT is fabricated via high temperature assisted direct wafer bonding after a local oxidation of silicon (LOCOS) to form evacuated cavities (vacuum gaps), and, thus, the device inherently has the ON layer beneath single-crystal silicon plates and vacuum gaps. Therefore, this device is ideal for this work. It allows us to test an elegant charge injection mechanism. By simply pulling in the plate a high electric field strength (∼ 8.9 MV/cm) is created in the ON layer for a designated time, which results in charge injection. These charges stay trapped in the ON layer and create an intrinsic electric field in the vacuum gaps, which would otherwise require an external dc bias voltage of 44% of the pull-in voltage. We successfully implemented a 5.3-MHz oscillator with this zero-bias resonator and achieved excellent noise performance of 0.06 Hz of Allan deviation.

  • highly sensitive detection of dmmp using a cmut based chemical Sensor
    IEEE Sensors, 2010
    Co-Authors: Hyunjoo Lee, Kwan Kyu Park, Mario Kupnik, Omer Oralkan, B T Khuriyakub
    Abstract:

    We present ppt-level detection of dimethyl methylphosphonate (DMMP), a common simulant used in detector calibrations for sarin gas, using a new capacitive micromachined ultrasonic transducer (CMUT) design with a mass sensitivity improved from 130 zg/Hz/µm2 to 48.8 zg/Hz/µm2. A low-noise oscillator using the CMUT as the frequency selective component exhibits an Allan deviation of 0.55 Hz at the presence of air flow. The CMUT Resonant Sensor was functionalized with a 50-nm thick proprietary polymer layer (Sandia National Laboratory, Albuquerque, NM). Our Sensor performance was reliably measured at the MIT Lincoln Laboratory where the accurate delivery of low concentrations of gases was ensured through stringent calibrations. Our Sensor response to various concentrations of DMMP in air (10 ppb-1 ppm) showed an excellent volume sensitivity of 30.6 pptv/Hz. Based on the system noise floor, we achieved a mass resolution of 26.9 zg/µm2 and a limit of detection of 16.8 pptv. In addition, the Sensor showed good selectivity to DMMP.

Minliang Liu - One of the best experts on this subject based on the ideXlab platform.

  • Airborne particulate matter classification and concentration detection based on 3D printed virtual impactor and quartz crystal microbalance Sensor
    Sensors and Actuators A-physical, 2016
    Co-Authors: Jiuxuan Zhao, Minliang Liu, Liang Liang, Wen Wang, Jin Xie
    Abstract:

    Abstract In this paper, design, fabrication and experiment of a miniature system for detection of airborne particulate matter (PM) are presented. The miniature system contains a virtual impactor and a quartz crystal microbalance (QCM) Resonant Sensor. The virtual impactor is fabricated by three-dimensional (3D) printing process for classifying airborne particles according to their size. The QCM Resonant Sensor is utilized to detect the mass of the separated particles from the virtual impactor. The design of virtual impactor is optimized by computational fluid dynamics simulation and the QCM for its resonance in thickness shear mode is analyzed by finite element method. Silicon dioxide powders with diameter in the range from 0.5 to 8 μm are successfully separated according to their size by the virtual impactor, which indicates that the classification characteristic coincides with the theoretical and simulation results. PM concentration in a chamber is measured by the proposed monitoring system and the experimental results show that the Resonant frequency of the QCM turns downward linearly with the PM mass loading increasing.

  • Airborne particulate matter classification and concentration detection based on 3D printed virtual impactor and quartz crystal microbalance Sensor
    2016 IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS), 2016
    Co-Authors: Jiuxuan Zhao, Minliang Liu, Wen Wang, Jin Xie
    Abstract:

    This paper reports a miniature system for detection of airborne particulate matter (PM), which contains a virtual impactor and a quartz crystal microbalance (QCM) Resonant Sensor. Silicon dioxide powders with diameter in the range from 0.5 to 8 μm are successfully separated by the virtual impactor according to their size. PM concentration in a chamber is measured by the proposed monitoring system and the experimental results show that the Resonant frequency of the QCM turns downward linearly with the PM mass loading increasing. The proposed monitoring system can complete measurement of PM concentration of 35 μg/m3 in only 23 seconds.