Micro Cantilever CO2 Gas Sensor Based on Mass

2015 ◽  
Vol 766-767 ◽  
pp. 528-533
Author(s):  
S. Subhashini ◽  
A. Vimala Juliet
Keyword(s):  
Residual Stresses ◽  
Resonant Frequency ◽  
Natural Frequency ◽  
Low Cost ◽  
High Sensitivity ◽  
The Other ◽  
Sensitive Coating ◽  
Metal Oxide Layer ◽  
Micro Cantilever

Sensors had gained importance in all fields of science and technology and development of real time small devices with high sensitivity for in situ measurements at low cost has gained momentum. Micromachined cantilever provides a solution to this hunt. MEMS cantilever are the simplest of all the other mechanical structures and hence is considered for the ease of fabrication. Here a chemical CO2 sensor is considered with the metal oxide layer as receptor to adsorb the CO2 molecules leading to an increase in mass and microcantilever as the transducer part converting the change in mass to change in natural frequency. The sensitive SnO2 layer increases the mass and hence decreases the resonant frequency. The inherent natural frequency of the cantilever is altered by the sensitive coating on top of the beam and the residual stresses present on the structure. In this paper, we investigate the SiO2 cantilever with SnO2 deposited on the top surface. Initially the microcantilever is analytically modelled and then is fabricated and characterized experimentally. Finally the error % is analysed between the analytical model and experimental results.

Micro-structured fibers and their applications in fiber-optic sensors and random fiber lasers

2018 ◽  
Vol 96 (4) ◽  
pp. 359-365
Author(s):  
Yanping Xu ◽  
Xiaoyi Bao
Keyword(s):  
Fiber Lasers ◽  
Fiber Optic ◽  
Axial Strain ◽  
Low Cost ◽  
High Sensitivity ◽  
Dynamic Parameter ◽  
Fiber Optic Sensors ◽  
Spectral Correlation ◽  
Sensing Applications ◽  
Micro Cantilever

Micro-structured fibers are important devices that have drawn intensive attentions and proved to be powerful platforms for various applications over the past decades due to their remarkable merits and advantages, such as small footprint, immunity to electromagnetic interferences, light weight, high physical flexibility, and low cost. Modifications in optical fibers can be used as light-steering elements to excite and couple back different core and cladding modes and form various in-fiber structures, including in-line fiber interferometer, fiber micro-cantilever, fiber random gratings, and so on. These micro-structures, when applied as fiber-optic sensors in the presence of external disturbances, show high sensitivity in terms of the significant changes in the guided light features. Novel micro-structured bend-insensitive fiber-based in-line fiber interferometer and micro-cantilever have been proposed to realize both static and dynamic parameter measurements, including temperature, axial strain, surrounding refractive index, and vibration. We have also developed a novel fiber random grating along with a spectral correlation algorithm for simultaneous measurement of three static measurands. To move a step forward, random fiber lasers based on fiber random grating are achieved for either improving the laser performances or sensing applications of temperature, strain, and ultrasound measurements with high sensitivity.

scholarly journals The Entangled Conductive Structure of CB/PA6/PP MFCs and Their Electromechanical Properties

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 961
Author(s):  
Yu Wang ◽  
Song Liu ◽  
Huihao Zhu ◽  
Huajian Ji ◽  
Guo Li ◽  
...  
Keyword(s):  
Treatment Process ◽  
Low Cost ◽  
Conductive Polymer ◽  
High Sensitivity ◽  
Polyamide 6 ◽  
Electromechanical Properties ◽  
Microfibrillar Composites ◽  
First Time ◽  
Selective Accumulation

In this work, carbon black (CB)/polyamide 6 (PA6)/polypropylene (PP) microfibrillar composites (MFCs) were fabricated through an extrusion (hot stretching) heat treatment process. The CB-coated conductive PA6 microfibrils with high aspect ratio were in situ generated as a result of the selective accumulation of CB at the interface. At the proper temperature, a 3D entangled conductive structure was constructed in the PP matrix, due to topological entanglement between these conductive microfibrils. This unique conductive structure provided the PP composites with a low electrical conductivity percolation threshold. Moreover, the electromechanical properties of conductive MFCs were investigated for the first time. A great stability, a high sensitivity and a nice reproducibility were achieved simultaneously for CB/PA6/PP MFCs. This work provides a universal and low-cost method for the conductive polymer composites’ (CPCs) fabrication as sensing materials.

Compliant and Low-Cost Humidity Sensors Using Nano-Porous Polymer Membranes

2004 ◽  
Author(s):  
Bozhi Yang ◽  
Burak Aksak ◽  
Shan Liu ◽  
Qiao Lin ◽  
Metin Sitti
Keyword(s):  
Relative Humidity ◽  
Room Temperature ◽  
Capillary Condensation ◽  
Low Cost ◽  
Polymer Membranes ◽  
High Sensitivity ◽  
Porous Polymer ◽  
Humidity Sensors ◽  
Water Leakage Detection

This paper proposes non-fragile compliant humidity sensors that can be fabricated inexpensively on various types of nano-porous polymer membranes such as polycarbonate, cellulose acetate, and nylon membranes. The sensor contains a pair of interdigitated electrodes deposited on the nano-porous polymer membranes. The resistance and/or capacitance between these electrodes vary at different humidity levels with a very high sensitivity due to the water adsorption (capillary condensation) inside the nano-pores. The proposed sensors are low-cost in both material and fabrication. Due to its compliance, the sensors can be suitable for certain applications such as in-situ water leakage detection on roofs, where people can walk on top of them. Testing results demonstrated that the sensor changes resistance within large range of humidity values. For most sensors, the resistance changes from 0.1 GΩ to 2000 GΩ when the relative humidity changes from 39% to 100% at room temperature. It takes about 4–8 minutes for the resistance to reach steady state when the sensor was taken from 100% to 39% relative humidity at the room temperature.

In/Ex-situ Detection of HBV DNA Using Dynamic Microcantilever

2009 ◽  
Vol 74 ◽  
pp. 337-340
Author(s):  
Tae Song Kim
Keyword(s):  
Dna Binding ◽  
Resonant Frequency ◽  
Protein Detection ◽  
High Sensitivity ◽  
Hbv Dna ◽  
Ex Situ ◽  
Label Free ◽  
Frequency Shifts ◽  
Label Free Detection

The microcantilevers have emerged as a versatile biosensor, and showed excellent performance such as high sensitivity, high selectivity, and label-free detection. They have been successfully used for the detection of nucleic acids, disease marker proteins, cells, and pathogens including small molecules. So far, our group has successfully demonstrated the marker protein detection using the actuating layer (PZT)-embedded microcantilevers for the last decade. Here, we introduce in/ex-situ monitoring of the DNA binding events using performance improved actuating layer-embedded microcantilever sensors. To obtain the stable and reliable resonant frequency shifts, the microcantilevers were passivated with parylene-C film for in-situ detection and perfluorosilane (PF-Si) film for ex-situ detection. To achieve the recognition layer, the probe DNA (37-mer including T10 spacers) specific to HBV DNA was immobilized on the gold-coated microcantilever, and followed by backfilling of ethylene glycol spacer (HSC11-EG3-OH) to increase the DNA binding efficiency. After the surface treatment, the detection of HBV DNA (27-mer) was performed through two manners, in-situ and ex-situ. Target DNA in the range of 1 to 20 M and 10 nM to 5 M were applied for the in-situ and ex-situ detection respectively, and the resonant frequency shifts according to the concentration was examined quantitatively. From the results, we explained the relationship between the DNA hybridization and the nanomechanical response. In addition, we presented a hypothesis on the different tendency of in-situ and ex-situ results.

Enhanced NO2 sensing performance of reduced graphene oxide by in situ anchoring carbon dots

2017 ◽  
Vol 5 (27) ◽  
pp. 6862-6871 ◽  
Author(s):  
Jing Hu ◽  
Cheng Zou ◽  
Yanjie Su ◽  
Ming Li ◽  
Nantao Hu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Gas Sensor ◽  
Carbon Dots ◽  
Room Temperature ◽  
Low Cost ◽  
High Sensitivity ◽  
Reduced Graphene ◽  
Sensing Performance

A room-temperature NO2 gas sensor of high sensitivity, selectivity and stability based on a low-cost, all-carbon nanoscale heterostructure and eco-friendly 2D rGO–CD hybrids.

scholarly journals An Hourglass-Shaped Wireless and Passive Magnetoelastic Sensor with an Improved Frequency Sensitivity for Remote Strain Measurements

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 359
Author(s):  
Limin Ren ◽  
Moyue Cong ◽  
Yisong Tan
Keyword(s):  
Resonant Frequency ◽  
Simple Structure ◽  
Low Cost ◽  
Signal Transmission ◽  
High Sensitivity ◽  
Detection Sensitivity ◽  
The Finite Element Method ◽  
Resonant Sensor ◽  
Parametric Studies ◽  
Sensitivity Problem

The conventional magnetoelastic resonant sensor suffers from a low detecting sensitivity problem. In this study, an hourglass-shaped magnetoelastic resonant sensor was proposed, analyzed, fabricated, and tested. The hourglass-shaped magnetoelastic resonant sensor was composed of an hourglass and a narrow ribbon in the middle. The hourglass and the narrow ribbon increased the detection sensitivity by reducing the connecting stress. The resonant frequency of the sensor was investigated by the finite element method. The proposed sensor was fabricated and experiments were carried out. The tested resonance frequency agreed well with the simulated one. The maximum trust sensitivity of the proposed sensor was 37,100 Hz/strain. The power supply and signal transmission of the proposed sensor were fulfilled via magnetic field in a wireless and passive way due to the magnetostrictive effect. Parametric studies were carried out to investigate the influence of the hourglass shape on the resonant frequency and the output voltage. The hourglass-shaped magnetoelastic resonant sensor shows advantages of high sensitivity, a simple structure, easy fabrication, passiveness, remoteness, and low cost.

scholarly journals Facile assembly and improved photocatalytic activity of a special cuprous oxide/copper fluoride heterojunction induced by graphene oxide

2021 ◽  
Vol 2 (6) ◽  
pp. 2000-2008
Author(s):  
Mengya Xi ◽  
Wanru Zhang ◽  
Zhiyuan Liu ◽  
Lixia Qin ◽  
Shi-Zhao Kang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Cuprous Oxide ◽  
Hydrogen Generation ◽  
Low Cost ◽  
The Other ◽  
Photocatalytic Hydrogen Generation

A low cost and stable Cu2O/CuF2 heterojunction was fabricated in situ induced by graphene oxide. Importantly, it showed a stable and greatly increased photocatalytic hydrogen generation compared with the other comparisons.

scholarly journals Cantilever-Based Sensor Utilizing a Diffractive Optical Element with High Sensitivity to Relative Humidity

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1673
Author(s):  
Catherine Grogan ◽  
Faolan Radford McGovern ◽  
Rory Staines ◽  
George Amarandei ◽  
Izabela Naydenova
Keyword(s):  
Relative Humidity ◽  
Diffraction Efficiency ◽  
Low Cost ◽  
Optical Element ◽  
High Sensitivity ◽  
Cantilever Deflection ◽  
Enhanced Sensitivity ◽  
Increased Sensitivity ◽  
Micro Cantilever ◽  
User Friendly

High-sensitivity and simple, low-cost readout are desirable features for sensors independent of the application area. Micro-cantilever sensors use the deflection induced by the analyte presence to achieve high-sensitivity but possess complex electronic readouts. Current holographic sensors probe the analyte presence by measuring changes in their optical properties, have a simpler low-cost readout, but their sensitivity can be further improved. Here, the two working principles were combined to obtain a new hybrid sensor with enhanced sensitivity. The diffractive element, a holographically patterned thin photopolymer layer, was placed on a polymer (polydimethylsiloxane) layer forming a bi-layer macro-cantilever. The different responses of the layers to analyte presence lead to cantilever deflection. The sensitivity and detection limits were evaluated by measuring the variation in cantilever deflection and diffraction efficiency with relative humidity. It was observed that the sensitivity is tunable by controlling the spatial frequency of the photopolymer gratings and the cantilever thickness. The sensor deflection was also visible to the naked eye, making it a simple, user-friendly device. The hybrid sensor diffraction efficiency response to the target analyte had an increased sensitivity (10-fold when compared with the cantilever or holographic modes operating independently), requiring a minimum upturn in the readout complexity.

scholarly journals A High Sensitive Flexible Pressure Sensor Designed by Silver Nanowires Embedded in Polyimide (AgNW-PI)

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 206 ◽  
Author(s):  
Hongfang Li ◽  
Guifu Ding ◽  
Zhuoqing Yang
Keyword(s):  
Pressure Sensor ◽  
Flexible Electronics ◽  
Silver Nanowires ◽  
Low Cost ◽  
Synthesis Method ◽  
High Sensitivity ◽  
Face To Face ◽  
Ultrathin Layers ◽  
Flexible Pressure Sensor

Silver nanowires (AgNW) have excellent electrical conductivity, transparency, and flexing endurance, and are broadly used in flexible electrodes and flexible sensors. This study mixed the silver nanowires and polyimide (PI) polymer using an in situ synthesis method, effectively reducing the problem of silver nanowires falling off the substrate. The selective wet etching method was firstly used to process the surface of AgNW-PI films, greatly enhancing the surface conductivity of AgNW-PI films. A flexible pressure sensor with high sensitivity was designed with two face-to-face AgNW-PI ultrathin layers. The experimental results show that our sensor presented a high sensitivity of about 1.3294 kPa−1 under a pressure of about 600 Pa, and when pressure continued to increase, the sensitivity decreased rapidly and reached saturation. Our flexible pressure sensor has the properties of low cost, high sensitivity, excellent repeatability, durability, and can detect various types of mechanical forces which could be utilized for flexible electronics.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Sign in / Sign up

Export Citation Format

Share Document