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Artykuły w czasopismach na temat "Microcantilever Beam"
1
Kim, Yun Young. "An evaluation technique for high-frequency dynamic behavior of a sandwich microcantilever beam". Journal of Sandwich Structures & Materials 21, nr 3 (22.05.2017): 1133–49. http://dx.doi.org/10.1177/1099636217708146.
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A method was developed to measure the first- and second-order vibration modes in a sandwich microcantilever beam oscillating in the megahertz frequency regime in the present study. Taking advantage of the ultrasonic frequency, a test platform was developed to induce free vibration of the microcantilever using a high-power radio frequency pulser that transmits tone burst signals to a contact transducer, and the resonant frequencies of the microcantilever were measured using a laser-optic interferometer. Results show that the microcantilever’s vibration above 8 MHz can be successfully detected, and its vibration modes were identified through a theoretical study based on the Euler–Bernoulli beam theory and a numerical analysis using the finite element method. The present study proposes a facile and effective way to actuate a high-speed sandwich microcantilever and detect its high-frequency response so that the technique can be employed to study the characteristics of micro- and nanomechanical sandwich structures and their properties.
2
LIM, TEIK-CHENG. "ANALYSIS OF AUXETIC BEAMS AS RESONANT FREQUENCY BIOSENSORS". Journal of Mechanics in Medicine and Biology 12, nr 05 (grudzień 2012): 1240027. http://dx.doi.org/10.1142/s0219519412400271.
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The mechanics of beam vibration is of fundamental importance in understanding the shift of resonant frequency of microcantilever and nanocantilever sensors. Unlike the simpler Euler–Bernoulli beam theory, the Timoshenko beam theory takes into consideration rotational inertia and shear deformation. For the case of microcantilevers and nanocantilevers, the minute size, and hence low mass, means that the topmost deviation from the Euler–Bernoulli beam theory to be expected is shear deformation. This paper considers the extent of shear deformation for varying Poisson's ratio of the beam material, with special emphasis on solids with negative Poisson's ratio, which are also known as auxetic materials. Here, it is shown that the Timoshenko beam theory approaches the Euler–Bernoulli beam theory if the beams are of solid cross-sections and the beam material possess high auxeticity. However, the Timoshenko beam theory is significantly different from the Euler–Bernoulli beam theory for beams in the form of thin-walled tubes regardless of the beam material's Poisson's ratio. It is herein proposed that calculations on beam vibration can be greatly simplified for highly auxetic beams with solid cross-sections due to the small shear correction term in the Timoshenko beam deflection equation.
3
Mouro, João, Rui Pinto, Paolo Paoletti i Bruno Tiribilli. "Microcantilever: Dynamical Response for Mass Sensing and Fluid Characterization". Sensors 21, nr 1 (27.12.2020): 115. http://dx.doi.org/10.3390/s21010115.
Pełny tekst źródłaStreszczenie:
A microcantilever is a suspended micro-scale beam structure supported at one end which can bend and/or vibrate when subjected to a load. Microcantilevers are one of the most fundamental miniaturized devices used in microelectromechanical systems and are ubiquitous in sensing, imaging, time reference, and biological/biomedical applications. They are typically built using micro and nanofabrication techniques derived from the microelectronics industry and can involve microelectronics-related materials, polymeric materials, and biological materials. This work presents a comprehensive review of the rich dynamical response of a microcantilever and how it has been used for measuring the mass and rheological properties of Newtonian/non-Newtonian fluids in real time, in ever-decreasing space and time scales, and with unprecedented resolution.
4
Song, Ya Qin, i Xiao Gang Yang. "Photothermal Response in Semiconducting Microcantilevers Produced by Laser Excitation". Advanced Materials Research 705 (czerwiec 2013): 81–84. http://dx.doi.org/10.4028/www.scientific.net/amr.705.81.
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The elastic vibration of semiconducting microcantilever, which was excited with a frequency-modulated pump laser, was optically detected use another probe beam. The photothermal signals were measurement near the resonant frequency. The changes of vibration amplitude and phase with the change of modulation frequency were obtained for a set of different sized microcantilevers. The results showed that the experimental results had a good agreement with the theoretical ones.
5
Liu, Xing Fang, Guo Guo Yan, Zhan Wei Shen, Zheng Xin Wen, Jun Chen, Ya Wei He, Wan Shun Zhao i in. "Theoretical Calculation and Simulation for Microcantilevers Based on SiC Epitaxial Layers". Materials Science Forum 954 (maj 2019): 26–30. http://dx.doi.org/10.4028/www.scientific.net/msf.954.26.
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The resonant frequency and Q factor of the SiC microcantilever were theoretically analyzed and calculated based on the stereotyped basic theories of the cantilever beam, and the relationship between the vibration mode and structure geometries was also simulated. Modal analysis by means of finite element method was performed on millimeter-, micron-and nanoscale microcantilevers, and the results showed that the smaller the microstructure was, the higher the resonant frequency can be obtained. The Q factor can be extracted from hamonic spectra after modal analysis, and the amplitude of Q factor was about 105. This paper shows that SiC epitaxial layers have great potential in microcantilevers.
6
Formica, Giovanni, Walter Lacarbonara i Hiroshi Yabuno. "Nonlinear Dynamic Response of Nanocomposite Microbeams Array for Multiple Mass Sensing". Nanomaterials 13, nr 11 (5.06.2023): 1808. http://dx.doi.org/10.3390/nano13111808.
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A nonlinear MEMS multimass sensor is numerically investigated, designed as a single input-single output (SISO) system consisting of an array of nonlinear microcantilevers clamped to a shuttle mass which, in turn, is constrained by a linear spring and a dashpot. The microcantilevers are made of a nanostructured material, a polymeric hosting matrix reinforced by aligned carbon nanotubes (CNT). The linear as well as the nonlinear detection capabilities of the device are explored by computing the shifts of the frequency response peaks caused by the mass deposition onto one or more microcantilever tips. The frequency response curves of the device are obtained by a pathfollowing algorithm applied to the reduced-order model of the system. The microcantilevers are described by a nonlinear Euler-Bernoulli inextensible beam theory, which is enriched by a meso-scale constitutive law of the nanocomposite. In particular, the microcantilever constitutive law depends on the CNT volume fraction suitably used for each cantilever to tune the frequency bandwidth of the whole device. Through an extensive numerical campaign, the mass sensor sensitivity estimated in the linear and nonlinear dynamic range shows that, for relatively large displacements, the accuracy of the added mass detectability can be improved due to the larger nonlinear frequency shifts at resonance (up to 12%).
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Munguia Cevantes, Jacobo Esteban, Juan Vicente Méndez Méndez, Hector Francisco Mendoza León, Miguel Ángel Alemán Arce, Salvador Mendoza Acevedo i Horacio Estrada Vázquez. "Si3N4 Young’s modulus measurement from microcantilever beams using a calibrated stylus profiler". Superficies y Vacío 30, nr 1 (25.03.2017): 10–13. http://dx.doi.org/10.47566/2017_syv30_1-010010.
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Stylus surface profiler has been widely used in order to measure Young’s modulus of silicon nitride (Si3N4) from microcantilever beams. Until now, several Si3N4 Young’s modulus values have been reported. It may be due to incomplete assessment of the microcantilever beams bending over its entire length or a lack of calibration of the stylus force system used in those works. We presented in this work an alternative method to measure the elastic modulus of MEMS thin layers in a rather accurate manner. A stylus force calibration is reported from a calibrated silicon microcantilever beam in order to measure the Si3N4 Young’s modulus. We reported Si3N4 Young´s modulus from three microcantilever beams, with values of 219.4 ± 0.6 GPa, 230.1 ± 3.4 GPa and 222 ± 11 GPa for 50 µm, 100 µm and 200 µm wide respectively, which are in good agreement with respect to the Si3N4 Young´s modulus which have been determined by other methods.
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Mojahedi, M., i M. Rahaeifard. "Static Deflection and Pull-In Instability of the Electrostatically Actuated Bilayer Microcantilever Beams". International Journal of Applied Mechanics 07, nr 06 (grudzień 2015): 1550090. http://dx.doi.org/10.1142/s1758825115500908.
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This paper deals with the static behavior of an electrostatically actuated bilayered microswitch on the basis of the modified couple stress theory. The beam is modeled using Euler–Bernoulli beam theory and equivalent elastic modulus and length scale parameter are presented for the bilayer beam. Static deflection and pull-in voltage of the beam is calculated using numerical and analytical methods. The numerical method is based on an iterative approach while the homotopy perturbation method (HPM) is utilized for the analytical simulation. Results show that there is a very good agreement between these methods even in the vicinity of the pull-in instability. Moreover, the effects of different parameters such as thicknesses of layers and length scale parameter on the static deflection and instability of the microcantilever are studied. Results show that for the cases with the equivalent length scale parameter comparable to the thickness of beam, the size-dependency plays significant roles in the static behavior of the bilayer microcantilevers.
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Nsubuga, Lawrence, Lars Duggen, Tatiana Lisboa Marcondes, Simon Høegh, Fabian Lofink, Jana Meyer, Horst-Günter Rubahn i Roana de Oliveira Hansen. "Gas Adsorption Response of Piezoelectrically Driven Microcantilever Beam Gas Sensors: Analytical, Numerical, and Experimental Characterizations". Sensors 23, nr 3 (17.01.2023): 1093. http://dx.doi.org/10.3390/s23031093.
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This work presents an approach for the estimation of the adsorbed mass of 1,5-diaminopentane (cadaverine) on a functionalized piezoelectrically driven microcantilever (PD-MC) sensor, using a polynomial developed from the characterization of the resonance frequency response to the known added mass. This work supplements the previous studies we carried out on the development of an electronic nose for the measurement of cadaverine in meat and fish, as a determinant of its freshness. An analytical transverse vibration analysis of a chosen microcantilever beam with given dimensions and desired resonance frequency (> 10 kHz) was conducted. Since the beam is considered stepped with both geometrical and material non-uniformity, a modal solution for stepped beams, extendable to clamped-free beams of any shape and structure, is derived and used for free and forced vibration analyses of the beam. The forced vibration analysis is then used for transformation to an equivalent electrical model, to address the fact that the microcantilever is both electronically actuated and read. An analytical resonance frequency response to the mass added is obtained by adding simulated masses to the free end of the beam. Experimental verification of the resonance frequency response is carried out, by applying known masses to the microcantilever while measuring the resonance frequency response using an impedance analyzer. The obtained response is then transformed into a resonance frequency to the added mass response polynomial using a polynomial fit. The resulting polynomial is then verified for performance using different masses of cantilever functionalization solution. The functionalized cantilever is then exposed to different concentrations of cadaverine while measuring the resonance frequency and mass of cadaverine adsorbed estimated using the previously obtained polynomial. The result is that there is the possibility of using this approach to estimate the mass of cadaverine gas adsorbed on a functionalized microcantilever, but the effectiveness of this approach is highly dependent on the known masses used for the development of the response polynomial model.
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Wong, WaiChi, HingWah Lee, Ishak A. Azid i K. N. Seetharamu. "Creep analysis of bimaterial microcantilever beam for sensing device using artificial neural network (ANN)". ASEAN Journal on Science and Technology for Development 23, nr 1&2 (30.10.2017): 89. http://dx.doi.org/10.29037/ajstd.95.
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In this study, a feed-forward back-propagation Artificial Neural Network (ANN) is used to predict the stress relaxation and behavior of creep for bimaterial microcantilever beam for sensing device. Results obtained from ANSYS® 8.1 finite element (FE) simulations, which show good agreement with experimental work [1], is used to train the neural network. Parametric studies are carried out to analyze the effects of creep on the microcantilever beam in term of curvature and stress deve loped with time. It is shown that ANN accurately predicts the stress level for the microcantilever beam using the trained ANSYS® simulation results due to the fact that there is no scattered data in the FE simulation results. ANN takes a small fraction of time and effort compar ed to FE prediction.
Rozprawy doktorskie na temat "Microcantilever Beam"
1
Norton, Andrew David. "Measuring and understanding grain boundary properties of engineering ceramics". Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:312cd97f-8680-4c02-b162-c0c7282bd343.
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This thesis aims to measure the mechanical properties of ceramics on the microscale using microcantilever beams. Focussed Ion Beam milled triangular cross-sectional beams (approximately 3 x 5 x 20µm) were fractured using a nanoindenter to measure the Young’s modulus, fracture strength, and fracture toughness. By developing the technique with a sapphire bicrystal, it was found that the mechanical properties could be successfully ascertained if correction factors were used. Experiments and theoretical work showed that sapphire and polycrystalline alumina beams undergo moisture assisted sub-critical crack growth when tested in air. Whilst corrections for the Young’s modulus have been previously reported, this is the first reported attempt to correct for the notch tip residual stress and the first to consider sub-critical crack growth. Once these factors were characterised using the sapphire bicrystal, the technique was applied to a range of different ceramics, such as polycrystalline α-alumina and silicon nitride. These are the first reported direct measurements the grain boundary toughness of these ceramics using microcantilever beams. The grain boundary toughness was correlated with the macroscopic fracture properties and the characteristics of the ceramic (grain boundary composition, impurities, and fracture mode). Two grades of α-alumina were used and the macro- and micro-scale properties extensively compared. The damage evolution during uniaxial compression of alumina was investigated in depth, and compared to a previous reported microcrack evolution model using the measured grain boundary toughness. Investigation of whether deformation twins formed during loading was undertaken and the phenomenon was shown to not occur.
2
Lin, Yi-Chun, i 林逸群. "Fatigue of an Electrostatically Driven Microcantilever Beam". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/ush77k.
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碩士國立清華大學
動力機械工程學系
93
With advancement of MEMS technology, the reliability of a microstructure has become a vital issue before a microdevice is widely accepted. Consequently, it is indispensable to understand the mechanical properties of a microstructure to meet the requirements of longer lifetime and reliable performance. This study investigates the fatigue characteristics of a microcantiliever beam (60-120μm long, 20μm wide, 2μm thick), one of the most common microstructures widely employed in sensors and actuators. Furthermore, a pad (500×500×2 and 560×560×2μm3 ), fabricated at the free end of the beam, is used for larger external electrostatic load generated between the specimen and the electrode with an air gap 525μm. In fatigue test, the specimen actuated by the applied voltage 150 and 200 V in the form of the digital wave at 100 Hz. The deflection of the beam is measured by the laser Doppler vibrometer. According to the experimental and ANSYS results, the displacement of the free end of the beam increases with the beam length, ranging from 61.3 to 597.8 nm; from S-N diagram, the maximum stress is inversely proportional to the corresponding fatigue life. The maximum stress occurs at the fixed end of the specimen between 14.3–32.0 MPa; the fatigue life lies between 6.1×10^6–1.4×10^8 cycles.
3
Hsieh, Kong-Yuan, i 謝庚源. "Fabrication of A Microcantilever Beam by Electroforming". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/31411329424289805856.
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碩士大葉大學
機電自動化研究所碩士班
94
This research focuses on the fabrication of a cantilever beam microstructure on a stainless steel substrate (SUS-301). Electroforming of a copper sacrificial layer and a nickel structural layer are used in the microfabriction process. A negative photoresist JSR-120N is used in the lithography process. The process parameters of soft bake, exposure and development are investigated. Pulse current is used in the electroforming process. A nickel cantilever beam is successfully fabricated by using a copper sacrificial layer and a nickel structural layer.
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Hung, Jeng-Nan, i 洪政男. "Bending Fatigue Life of Polycrystalline Silicon Microcantilever Beam". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/88312660424363932960.
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博士國立清華大學
動力機械工程學系
100
In light of the rapid advancement in IC/MEMS/NEMS technology, the reliability is an essential factor for a successful microdevice product. However, the reliable application of these devices often depends on the fatigue of their microstructure. Microcantilever beam and polycrystalline silicon (polysilicon) are the most often used structure and material in microdevices, respectively. Therefore, their mechanical fatigue properties need to be characterized to predict the lifetime of the microdevices. This study presents the fatigue life of polysilicon microcantilever beam in bending by various testing methods, including microactuator, MTS Tytron250 microforce testing system and piezoelectric actuator. During microactuator testing, the fatigue life persists up to millions of cycles without failure, because the amplitude of displacement is small. Based on the results of the MTS Tytron250 microforce testing system and the piezoelectric actuator, it can be concluded that large stress reduces the number of cycles, namely the fatigue life is inversely proportional to the stress. In this study, an empirical correlation is established for predicting bending fatigue of polysilicon microcantilever beam. This correlation demonstrated the influence of applied frequency on fatigue life. The high stress reduced the fatigue life, and low frequencies enhanced this effect. Moreover, the collective plot of polysilicon by various testing mechanisms, such as tension, bending and torsion, will provide the microdevice designer and researcher with a good reference for various applications.
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Chiou, Yong-Shan, i 邱永山. "Fabrication and Prostate Specific Antigen Testing of a Piezoresistive Microcantilever Beam Biosensor". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/13246312638502159199.
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碩士臺灣大學
應用力學研究所
95
Prostate cancer is becoming one of the top three major cancer killers for elderly men in the west, and it is also one of the ten major cancers reported of Taiwan in 2006. Prostate specific antigen (PSA) is found to be the most valuable tumor sign of prostate cancer. It has become the highest value of biomarkers in cancers. In this study, the piezoresistive microcantilever is required for operation in a phosphate buffered saline solution or human plasma which is to maintain a specific pH environment of a strong electrolyte. As a result, the device is required to be electrically insulated in solution environment. The selected silicon nitride is used to conform to the requirements for the insulting material. The cantilevers are designed in 150 or 200 μm long, 50 μm wide and about 1.4 μm thick. The integrated piezoresistive resistors are 100 μm long, 50 μm wide and 200 nm thick, and the expected resistance is approximately 4 kΩ. Meanwhile, the gold layer (30 nm thick) coated on the cantilever surface is necessary for chemical reaction of biolinker, and thus the sensing surface of specific protein adsorption and its associated recognition. In addition to the microcantilever device, several important issues need to be considered in height, length, width, and the total volume of the channel, as well as the flow field in the microchannel. In the micro-fluid system, the laminar flow is also required to reduce the noise from vibrations of the cantilever. The biosensor is wire bonded directly on the printed circuit board (PCB) with a height of 470μm, connected to the signal processing device on the PCB. Preliminary result of PSA detection was obtained by this piezoresistive microcantilever. The device is confirmed to be tested in solution environment and thus its preliminary feasibility. More testing is required for further verification in PSA detection.
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Lin, Kuan-Yi, i 林官毅. "Fabrication and C-Reaction Protein Testing of a Piezoresistive Microcantilever Beam Biosensor". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/93702483181517137559.
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碩士臺灣大學
應用力學研究所
95
C-reaction protein( CRP ) is becoming one of important biomarkers in cardiovascular disease, myocardial infarction( MI ), and atherosclerosis. Higher concentration of CRP in serum elevates the risk of those diseases. Despite of existing techniques of surface plasmon resonance( SPR ), enzyme-linked immunosorbent assay( ELISA ) and others developed, the present piezoresistive microcantilever biosensors are sensitive, potentially inexpensive, label-free and of ease-of-use in miniaturization. To be detected, the microcantilevers are placed inside a microfluidic system that has a volume of several ten microliters. As probed biomolecules are transported onto a sensing surface of microcantilevers, specific recognition occurs, resulting in biomolecular conformation change and associated nanomechanic deflection of induced surface stresses. The deflection is mostly detected by an optical lever of detection system. Despite sensitive detection, the entire optical measurement is bulky and hardly aligned in readout system. For biomolecular recognition, the piezoresistive cantilever is required for operation in a phosphate buffered saline solution or human plasma which is to maintain a specific pH environment of a strong electrolyte. As a result of device electrical insulation to its solution, the piezoresistive cantilever is required to be surrounded by the insulating material to prevent electric leakage and unwanted chemical reaction on the sensing surface. The selected silicon nitride is used to conform to the requirements for the insulting material. The cantilevers are designed in 150 or 200 μm long, 50 μm wide and about 1.4 μm thick. The integrated piezoresistive resistors are 100 μm long, 50 μm wide and 200 nm thick, and the expected resistance is approximately 4 kΩ. Meanwhile, the gold layer (30 nm thick) coated on the cantilever surface is necessary for chemical reaction of biolinker, and thus the sensing surface of specific protein adsorption and its associated recognition. Preliminary result of CRP detection was obtained by this piezoresistive microcantilever. The device is confirmed to be tested in solution environment and thus its preliminary feasibility. More testing is required for further verification in CRP detection.
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Phani, Arindam. "Novel Diffraction Based Deflection Profiling For Microcantilever Sensor Technology". Thesis, 2011. https://etd.iisc.ac.in/handle/2005/2433.
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A novel optical diffraction based technique is proposed and demonstrated to measure deflections of the order of ~1nm in microcantilevers (MC) designed for sensing ultra-small forces of stress. The proposed method employs a double MC structure where one of the cantilevers acts as the active sensor beam, while the other as a reference. The active beam can respond to any minute change of stress, for example, molecular recognition induced surface stress, through bending (~1nm) relative to the other fixed beam. Optical diffraction patterns obtained from this double slit aperture mask with varying slit width, which is for the bending of MC due to loading, carries the deflection profile of the active beam. A significant part of the present work explores the possibility of connecting diffraction minima (or maxima) to the bending profile of the MC structure and thus the possibility to measure induced surface stress. To start with, it is also the aim to develop double MC sensors using PHDDA (Poly – Hexane diol diacrylate) because this material has the potential to achieve high mechanical deformation sensitivity in even moderately scaled down structures by virtue of its very low Young’s modulus. Moreover, the high thermal stability of PHDDA also ensures low thermally induced noise floors in microcantilever sensors. To demonstrate the proposed optical diffraction-based profiling technique, a bent microcantilever structure is designed and fabricated by an in-house developed Microstereolithography (MSL) system where, essentially one of the microcantilevers is fabricated with a bent profile by varying the gap between the two structures at each cured 2D patterned layer. The diffraction pattern obtained on transilluminating the fabricated structure by a spherical wavefront is analyzed and the possibility of obtaining the deflections at each cross section is ascertained. Since the proposed profiling technique relies on the accurate detection and measurement of shifts of intensity minima on the image plane, analysis of the minimum detectable shift in intensity minima for the employed optical interrogation setup with respect to the minimum detectable contrast and SNR of the optical measurement system is carried out, in order to justify the applicability of the proposed minima intensity shift measurement technique. The proposed novel diffraction based profiling technique can provide vital clue on the origins of surface stress at the atomic and molecular level by virtue of the entire bent profile due to adsorption induced bending thereby establishing microcantilever sensor technology as a more reliable and competitive approach for sensing ultra-low concentrations of biological and chemical agents.
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Phani, Arindam. "Novel Diffraction Based Deflection Profiling For Microcantilever Sensor Technology". Thesis, 2011. http://hdl.handle.net/2005/2433.
Pełny tekst źródłaStreszczenie:
A novel optical diffraction based technique is proposed and demonstrated to measure deflections of the order of ~1nm in microcantilevers (MC) designed for sensing ultra-small forces of stress. The proposed method employs a double MC structure where one of the cantilevers acts as the active sensor beam, while the other as a reference. The active beam can respond to any minute change of stress, for example, molecular recognition induced surface stress, through bending (~1nm) relative to the other fixed beam. Optical diffraction patterns obtained from this double slit aperture mask with varying slit width, which is for the bending of MC due to loading, carries the deflection profile of the active beam. A significant part of the present work explores the possibility of connecting diffraction minima (or maxima) to the bending profile of the MC structure and thus the possibility to measure induced surface stress. To start with, it is also the aim to develop double MC sensors using PHDDA (Poly – Hexane diol diacrylate) because this material has the potential to achieve high mechanical deformation sensitivity in even moderately scaled down structures by virtue of its very low Young’s modulus. Moreover, the high thermal stability of PHDDA also ensures low thermally induced noise floors in microcantilever sensors. To demonstrate the proposed optical diffraction-based profiling technique, a bent microcantilever structure is designed and fabricated by an in-house developed Microstereolithography (MSL) system where, essentially one of the microcantilevers is fabricated with a bent profile by varying the gap between the two structures at each cured 2D patterned layer. The diffraction pattern obtained on transilluminating the fabricated structure by a spherical wavefront is analyzed and the possibility of obtaining the deflections at each cross section is ascertained. Since the proposed profiling technique relies on the accurate detection and measurement of shifts of intensity minima on the image plane, analysis of the minimum detectable shift in intensity minima for the employed optical interrogation setup with respect to the minimum detectable contrast and SNR of the optical measurement system is carried out, in order to justify the applicability of the proposed minima intensity shift measurement technique. The proposed novel diffraction based profiling technique can provide vital clue on the origins of surface stress at the atomic and molecular level by virtue of the entire bent profile due to adsorption induced bending thereby establishing microcantilever sensor technology as a more reliable and competitive approach for sensing ultra-low concentrations of biological and chemical agents.
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Kolli, Venkateswara Rao. "Integrated Optic Microring Resonator based Sub-μN force and Force and Acceleration Sensors". Thesis, 2017. http://etd.iisc.ac.in/handle/2005/4317.
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Microring resonators have rapidly emerged in the past few years as a new sensing platform for
miniaturization of modern integrated optical devices. Ring resonator are having advantages of
compactness, stability with respect to back reflections, do not need facets or gratings for optical
feedback, strong optical field enhancement inside cavities, high wavelength selectivity, narrow line
width, high Q-factor and high sensitivity. These unique characteristics made microring resonator as
promising platform for integrated photonics.. A generic ring resonator consists of an optical
waveguide which is looped back on it self and coupled with a single or double bus waveguide.
In this thesis, a compact microring resonator (MRR) is proposed and optimized to exhibit high
sensitivity and quality factor. Also, force and acceleration sensing applications of MRR are
discussed. Electromagnetic computations are done using Finite Difference Time Domain (FDTD)
method. Fabrication and characterization of microring is also carried out. While the main emphasis
is on design and analysis, this experimental work supports better understanding of practical issues
in study of microring resonators. Then, the force sensing application of the optimized microring
resonator is presented. The design and modeling of the devices, including the mechanical properties
of the microcantilever beam, are done by using a Finite Element Method (FEM). The force
sensing characteristics are presented for the force range of 0 to 1 μN. The drawbacks of single
MRR can be overcome by using serially coupled double microring resonator(SC-DMRR) and
serially coupled double racetrack resonator (SC-DRTR) with vernier effect. They provide, high
FSR, low FWHM, high Q-factor and high sensitivity. By using SC-DMRR as an optical sensing
element, a novel IO MEMS SC-DMRR based force sensor is proposed, resulting in high Q-factor of
19000 and force sensitivity of 100 pm/ 1μN. Further, in order to increase the sensitivity, a novel SCDRTR
based force sensor is proposed.
The study is expanded to photonic crystal microring resonator (PC-MRR) structures, where a PCMRR
is designed in a hexagonal lattice of air holes on a silicon slab. A novel approach is used to
optimize PC-MRR to achieve high Q-factor. A high sensitive force sensor based on PC-MRR
integrated with silicon micro cantilever is presented. The force sensing characteristics are presented
for forces in the range of 0 to 1 μN. For forces which are in the range of few tens of μN, a force
sensor with bilayer cantilever is considered. Further, the PC-MRR equivalent microring resonator is
designed and analyzed for comparison between the force sensors. Finally, a novel IO MEMS
serially coupled racetrack resonator based accelerometer is proposed and the required
characteristics like sensitivity and dynamic range are reported.
In conclusion, IO micro ring resonators are the best candidates to design and develop force and
acceleration sensors in the sub-μN sensitivities.
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Stacco, Jacques S. "Observation of Analyte-Induced Deflections for Uncoated Microcantilevers using the Focused Ion Beam Procedure". 2008. http://trace.tennessee.edu/utk_gradthes/454.
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It has been found that structural modifications, involving the creation of submicron scale grooves on uncoated silicon nitride microcantilevers, allow microcantilevers to display analyte-induced deflections which have not been previously observed. The submicron grooves were created through the use of a focused ion beam procedure to mill deep and narrow grooves without the subsequent deposition of a chemically reactive coating. These modifications significantly increase (by approximately 400%) an uncoated microcantilever’s ability detect analytes such as water vapor, ethyl alcohol, acetone vapor, argon, and 1-mononitrotoluene. The intention of the experiment was to achieve greater microcantilever deflections by increasing an uncoated microcantilever’s surface energy and surface area through the least amount of surface modifications. Accordingly, one to three grooves with a depth greater than the thickness of the microcantilevers were achieved by milling the grooves at a maximum angle of 45 degrees. One microcantilever, with a 100 nm wide groove (milled at an angle of 45 degrees relative to the surface normal and to a depth of 1.3 micrometers) deflected by 400 nm in the presence of an argon-ethanol mixture. The same microcantilever also exhibited a deflection magnitude which increased with gas concentration. When comparing the set of milled microcantilevers used in this experiment, deflections were found to increase as the width of the grooves decreased and the depth and number of grooves increased.
Części książek na temat "Microcantilever Beam"
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Schultz, Joshua A., Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Nicholas J. Nigro, Luke A. Beardslee i Oliver Brand. "Timoshenko Beam Model for Lateral Vibration of Liquid-Phase Microcantilever-Based Sensors". W MEMS and Nanotechnology, Volume 5, 115–24. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-00780-9_15.
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Wang, Ni, Bruce W. Alphenaar, Robert S. Keyton i Roger D. Bradshaw. "Improvement of Piezoresistive Microcantilever Beams for Gas Detection and Sensing". W MEMS and Nanotechnology, Volume 2, 147–55. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-8825-6_21.
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Sarkar, Dipta, Partha Pratim Chakraborty, B. Terry Beck i Zayd C. Leseman. "Two-Dimensional Heat Transfer Considerations for Thermoreflectance Measurements". W ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-88657.
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In the Suspended ThermoReflectance (STR) technique a microcantilever is heated with a laser power at the free end of the microcantilever and as heat propagates through it, another laser is used to measure the temperature along the beam.[1] In this paper, the heat equation is solved for two-dimensional heat flow in the microcantilever to determine the material’s thermal conductivity and heat capacity. Two of the dimensions of the microcantilever, width and length, are significantly greater than the third dimension, the thickness, leading to the two-dimensional approximation. Two boundaries along the length of the structure and one boundary along the width are assumed to be under Dirichlet boundary conditions, while the other boundary has Neumann condition. The Neumann or flux condition has a Gaussian profile due to the nature of laser beam intensity. The heat equation is solved using under 3 different flux conditions: (1) Steady-state, (2) Transient, and (3) Periodic. A steady-state condition mimics the experimental condition when a continuous wave laser is used to heat the microcantilever’s tip. A transient condition is possible when quickly removing or adding the continuous wave laser’s flux from the microcantilever’s tip using a chopper. Finally, a periodic condition can be achieved when an electro-optic modulator is utilized experimentally. Closed form analytical expressions are evaluated against the finite element model and experimental results for microcantilever beams and micro-structures of Si that have lengths on the order of a mm, width on the order of 100 microns, and thicknesses of 1 micron or less.
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Wavering, Thomas A., Scott A. Meller, Mishell K. Evans, Charles Pennington, Mark E. Jones, Roger VanTassell, Kent A. Murphy, William H. Velander i E. Valdes. "Interferometric optical fiber microcantilever beam biosensor". W Environmental and Industrial Sensing, redaktor Robert A. Lieberman. SPIE, 2000. http://dx.doi.org/10.1117/12.411717.
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Rogers, James W., Thomas J. Mackin i Leslie M. Phinney. "A Thermomechanical Model for Adhesion Reduction of MEMS Microcantilevers". W ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/mems-23823.
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Abstract We present a model for reducing adhesion in MEMS structures using laser heating and compare the model to experimental results. Using a fracture mechanics model, the interface between the stiction-failed microcantilever and the substrate is treated as a crack, and the energy release rate is calculated using elastic theory. In order to include the effect of laser irradiation of the microcantilevers, an associated thermal strain energy is included in the fracture model. As the beam peels, the free length reaches a critical value where the beam buckles, decreasing the energy of the system. The results of the model predict a temperature difference of 100 K is able to repair microcantilevers as long as 600 μm. Experiments are performed that demonstrate the peeling of stiction-failed beams from the substrate after laser irradiation as predicted by the thermomechanical model.
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Chou, Chia-Ching, Shu-Wei Chang i Chuin-Shan Chen. "Alkanethiol Self-Assembled Monolayers on Microcantilever Biosensor". W ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13214.
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Microcantilever-based biosensors are rapidly becoming an enabling sensing technology for a variety of label-free biological applications due to their wide applicability, versatility and low cost. It is thus imperative for us to reveal the physical origin of adsorption-induced deformation, and to further analyze its implication of microscopic mechanisms on macroscopic deformation. In the paper, we study adsorption-induced surface stresses and microcantilever motion in alkanethiolate SAMs on Au surface. We develop a multiscale method that can analyze deformation of micro-cantilever beam subjected to bio-adsorption mechanisms calculated by ab-initio simulation and classical molecular dynamics. The adsorption mechanisms of different SAMs adsorbed on Au(111) surface, in the dry and liquid phase, are studied by ab-initio simulation and the adsorption-induced stresses are calculated through the multiscale method. The results give insight into the atomic forces and positions that play a key role in producing adsorption-induced surface stresses and resultant mechanical bending of microcantilevers.
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Afshari, Mana, i Nader Jalili. "Modeling Molecular Interactions Arising From Adsorbed Biological Species on the Microcantilever Biosensor Surface". W ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15198.
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This paper presents a general framework for modeling resonance frequency changes induced due to the surface stress arising from the adsorption of biological species on the surface of the microcantilever biosensors. Very few works have dealt with the effect of surface stress on the resonance frequency shifts of microcantilevers and mainly assume a simple model for the vibrating microcantilever beam. In the proposed modeling framework, the nonlinear terms due to beam's flexural rigidity from macro- to micro-scale as well as varying nature of the longitudinal force resulting from the surface stress are considered. It is demonstrated that through applying the mathematical expression formulated in this paper, desired biological species can be easily and accurately detected.
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Faegh, Samira, Sohrab Eslami i Nader Jalili. "An Adaptive Amplitude-Based Self-Sensing Piezoelectrically-Driven Microcantilever Sensor". W ASME 2010 Dynamic Systems and Control Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/dscc2010-4146.
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This paper presents an adaptive amplitude-based self-sensing strategy for ultrasmall tip mass estimation utilizing piezoelectrically-driven microcantilevers. The proposed configuration overcomes the inherent shortfalls (e.g., thermal drifts, electronic noise, and restriction to use in liquid media) currently exist in conventional systems. The microcantilever operates in self-sensing mode utilizing a piezoelectric patch deposited on the cantilever surface. The piezoelectric patch actuates the beam and at the same time senses the beam vibration through inverse and direct piezoelectric effects, respectively, which enables measurement of the surface induced stress. To remedy the measurement limitation at the microscale due to lack of sensitivity and temperature dependency of piezoelectric, an advanced auto-tunable self-sensing controller is proposed which balances the capacitance bridge network. Moreover, an optimization strategy is developed to minimize the error of the output voltage considering the fact that the individual time dependent coordinates are not measurable. Mathematical models and equations of motion are obtained using the Hamilton’s principle treating the microcantilever as a distributed-parameters system. Simulations are performed to demonstrate the effectiveness of the proposed technique.
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He, J., i C. M. Lilley. "Modeling and Characterization of Nanowires With Microcantilever Beams". W ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13762.
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Mechanical behavior of a nanowire-microcantilever beam structure under electrostatic actuation was studied using the FE method. A comparison for the resonant frequencies between a nanowire-microcantilever structure and a microcantilever only is presented. Several factors affecting the resonant frequency of the nanowire-microcantilever structure, such as actuation voltage and fabrication effects on geometries are discussed. Also, alignment effect of the nanowires with the microcantilever beam is investigated. This study can be utilized to predict Young's modulus of nanowires.
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Rokni D. T., Hossein, Abbas S. Milani, Rudolf J. Seethaler i Jonathan Holzman. "The Effect of Carbon Nanotubes on the Natural Frequencies of Microcantilever Beams". W ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28494.
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In this study, the natural frequencies and mode shapes of carbon nanotube (CNT) reinforced polymer composite microcantilever beams are investigated by means of a micromechanical model and the three-dimensional finite element analysis. Microcantilever beams are made of Poly vinyl chloride (PVC) and reinforced with multi-wall carbon nanotubes (MWCNTs). MWCNTs can be distributed along the length/width/thickness of the nanocomposite beam. To validate the accuracy and effectiveness of the model, a direct comparison of results is made with an analytical solution for a test case. Next, various material types of the nanocomposite microcantilever beam are introduced and the effect of different distribution patterns and the weight-percents (wt%) of MWCNTs on the first six natural frequencies and mode shapes is found.
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Hosseini, Mahmoud Reza, i Nader Jalili. "A New Nanomechanical Cantilever Sensing Paradigm Using Piezoelectric Boron Nitride Nanotube-Based Actuation". W ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-35425.
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Nanomechanical Cantilever Sensors (NMCS) have recently attracted a widespread attention for use in different nano- and micro-size applications such as studying the nanoscale surface topography by scanning probe microscopy and atomic force microscopy (AFM). In newer AFM systems, a sharp probe is placed at the tip of the microcantilever and a piezoelectric patch actuator deposited on the cantilever surface produces the movements of the probe above the examined surface. Similar system can be also utilized for mass sensing purposes by adding an unknown mass to the tip and measuring the beam deflection and the amount of shift in the resonance frequency that is caused by the addition of the tip mass. This sensing paradigm finds many applications in medical and biological fields such as DNA strand and bacteria weight measurement. However, one of the major issues in all piezoelectrically-actuated microcantilevers is the low actuation energy of the piezoelectric patch. Most of the current and widely used piezoelectric materials possess low mechanical characteristics such as low Young’s modulus of elasticity, low yield strength and most importantly incompatibility with most biological species and environment. It has been shown that both carbon and boron nitride nanotubes (CNT and BNNT) possess outstanding mechanical, chemical and electrical properties with acceptable piezoelectricity which make them suitable for microcantilever actuation applications. In this paper, a multi-physics multi-scale model is proposed in which the actuation of microcantilevers is produced by two sets of nanotube layers. Through extensive simulations, BNNTs were chosen to be used as the actuators because of their enhanced piezoelectric characteristics compared to CNTs. The modeling framework proposed here is used to investigate the effects of deposited tip mass with different weights on frequency response and resonance frequency of the microcantilever beam. These microbeams are made of aluminum or titanium materials and the results are compared with each other.
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Hocheng, Hong, i Jeng-Nan Hung. "Various Fatigue Testing of Polysilicon Microcantilever Beam in Bending". W 2007 Digest of papers Microprocesses and Nanotechnology. IEEE, 2007. http://dx.doi.org/10.1109/imnc.2007.4456251.
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