Micromechanical Cantilever Arrays Research Articles

Dynamics of impurity attraction and repulsion of an intrinsic localized mode in a driven 1-D cantilever array.

Both low frequency and high frequency impurity modes have been produced in a SiN micromechanical cantilever array by illumination with either an infrared or visible laser. When such laser-induced impurities are placed near a driven intrinsic localized mode (ILM), it is either repelled or attracted. By measuring the linear response spectrum for these two cases, it was found that vibrational hopping of the ILM takes place when the natural frequency of the ILM and an intrinsic even symmetry linear local mode are symmetrically located about the driven ILM frequency so that parametric excitation of these two linear modes is enhanced, amplifying the lateral motion of the ILM. Numerical simulations are consistent with these signature findings. It is also demonstrated that the correct sign of the observed interaction can be found with a harmonic lattice-impurity model but the magnitude of the effect is enhanced in a nonlinear lattice.

A study on feedback control of intrinsic localized modes in a micro-mechanical cantilever array

ySchool of Engineering, The University of Shiga Prefecture2500 Hassaka-cho, Hikone, Shiga 522-8533, JapanzDepartment of Electrical Engineering, Kyoto UniversityKatsura, Nishikyo, Kyoto 615-8510, JapanEmail: kimura.m@e.usp.ac.jp, matsushita.y@e.usp.ac.jp, hikihara.takashi.2n@kyoto-u.ac.jpAbstract —Intrinsic localized mode (ILM), which isalso called discrete breather (DB), is an energy localizedvibration in nonlinear coupled oscillators. It is well knownthat the ILM can move in the system without decay of itsenergy concentration. This paper shows that the positionof ILM can be controlled by proportional-derivative con-trol. To create a force to the ILM, linear on-site coe cientsare modulated linearly with respect to the lattice number.Namely, value of the linear on-site coe cients linearly in-crease/decrease as the lattice number increases. Magnitudeof the tilt is adjusted with PD control scheme. As a result ofnumerical simulations, a standing ILM is successfully con-trolled toward a reference position with keeping its energyconcentration.1. IntroductionSpatially localized and temporary periodic vibrations of-ten appear in nonlinear coupled oscillators [1]. The energylocalized vibration in discrete media which is rst discov-ered by A. J. Sievers and S. Takeno [2] is called intrinsic lo-calized mode(ILM) or discrete breather(DB). Experimentalobservations of ILM have been reported for a variety ofphysical system in this decade as well as theoretical andnumerical studies. In particular of them, the observationin micro-mechanical cantilever array allow us to expectthe realization of applications using ILM in micro/nano-engineering [3], because it was also observed that ILM canmove without decaying its energy concentration and can bemanipulated by an extraneous stimulus [4].For the realization of such application, the controlscheme for the ILM should be established. In our previ-ous research, it has been shown that a standing ILM losesits stability by parametric excitation [5]. This result impliesthat appropriately adjusting parameter can creates a force tostanding ILM, because the parametric resonance is usuallycaused by changing a potential shape. Therefore, if the pa-rameter of the system is changed appropriately based on thedistance from the reference position, the position of ILMcan be controlled by using an ordinary control method. Inthis paper, proportional-derivative control is applied to thecontrol of the position of ILM. First, an approximate equa-tion describing the motion of traveling ILM is derived. Sec-ond, behavior of moving ILM is shown when on-site linearcoe cients are gradually changed with respect to the lat-tice number. Finally, the proportional-derivative control ofILM is demonstrated and discussed.2. Coupled Cantilever Array and Standing ILMMicro-cantilever array is one of nonlinear coupled oscil-lators having ILM [3]. By focusing on the rst mode ofbeam vibrations, motions of each cantilever's tip are ap-proximately described by the following ordinary di eren-tial equation [4,6,7],¨u

A numerical study on parametric resonance of intrinsic localized modes in coupled cantilever arrays

ySchool of Engineering, The University of Shiga Prefecture2500 Hassaka-cho, Hikone, Shiga 522-8533, JapanzDepartment of Electrical Engineering, Kyoto UniversityKatsura, Nishikyo, Kyoto 615-8510, JapanEmail: kimura.m@e.usp.ac.jp, matsushita.y@e.usp.ac.jp, hikihara.takashi.2n@kyoto-u.ac.jpAbstract —In a coupled cantilever array modeled as acoupled ordinary di erential equation, symmetric and an-tisymmetric intrinsic localized modes (ILMs) exist. Thesymmetric ILM is stable while the other is unstable underthe regime in which the ratio in nonlinearities of inter-siteand on-site potentials is less than the critical value at whichthe stability change occurs. This paper shows that a sta-ble ILM loses its stability when the system is parametri-cally excited. If the amplitude of parametric excitation islarge enough, the destabilized ILM wanders in the wholesystem. The parameter region where the instability occursare numerically investigated and compared with that in theMathieu equation. The similarity of the shape of the re-gions strongly suggests that the instability is caused by theparametric resonance.1. IntroductionSpatially localized and temporary periodic vibrations of-ten appear in nonlinear coupled oscillators [1]. The energylocalized vibration in discrete media which is rst discov-ered by A. J. Sievers and S. Takeno [2] is called intrinsic lo-calized mode(ILM) or discrete breather(DB). Experimentalobservations of ILM have been reported for a variety ofphysical system in this decade as well as theoretical andnumerical studies. In particular of them, the observationin micro-mechanical cantilever array allow us to expectthe realization of applications using ILM in micro/nano-engineering [3], because it was also observed that ILM canmove without decaying its energy concentration and can bemanipulated by an extraneous stimulus [4].For the realization of such application, the controlscheme for the ILM should be established. The capture andrelease manipulation using the stability change is proposedas an alternative method to manipulate ILM in a micro-cantilever array [5]. For the manipulation method, it isutilized that a stable ILM begins to move after it loses itsstability. Therefore, the manipulation is a way to generatemoving ILM. In this paper, we propose another method togenerate moving ILM by parametric excitation of the ratioin nonlinearities. We rst investigate how moving ILMsbehave around a stable ILM. The motion of moving ILM isapproximated by a simple equation of pendulum. Then, be-haviors of moving ILM created by parametric excitation areshown. Finally, the region where a stable solution loses itsstability by parametric excitation is computed for an ILM,and is compared with that of the Mathieu equation.2. Coupled Cantilever ArrayCantilever array, which is often used as a coupled me-chanical resonator in nano/micro-engineering, is one ofnonlinear coupled oscillators in which ILM can be ob-served experimentally [3]. The motion of cantilevers canapproximately be described by ordinary di erential equa-tion [4–6],u¨

Preface

This issue of Discrete and Continuous Dynamical Systems - Series S is a compilation of papers representing the current state-of-the-art on the field of localized excitations and their role in the dynamics of complex physical systems. During the last two decades, an impressive volume of theoretical and experimental work has been devoted to the existence, stability and dynamics of such coherent structures. They have been identified as critical components of numerous continuous and discrete dynamical systems and, depending on the context (and their particular form), they may be referred to as solitons, instantons, kinks, breathers, or quodons, among many others. We nowadays think of such localized nonlinear excitations as being ubiquitous in nature due to their experimental realization in many diverse systems including, but not limited to, optical fibers and waveguide arrays, photonic crystals, Bose-Einstein condensates, molecular crystals, quasi-one-dimensional solids, Josephson-junctions and arrays thereof, layered silicates, micromechanical cantilever arrays, uranium crystals, pendulum arrays, water waves, electrical transmission lines, ferromagnetic and antiferromagnetic materials, granular crystals and so on. Additionally, they are also conjectured to play an important role in denaturation transitions and bubble formation in DNA, protein folding, atom ejection and defect migration in crystals, low-temperature reconstructive transformations, and many others. The study of nonlinear localized excitations is a long-standing challenge for research in basic and applied science, as well as engineering, due to their importance in understanding and predicting phenomena arising in nonlinear and complex systems, but also due to their potential for the development and "design" of novel applications. <br><br>For more information please click the “Full Text” above.

Logic operations demonstrated with localized vibrations in a micromechanical cantilever array

A method is presented for realizing logic operations in a micro-mechanical cantilever array based on the timed application of a lattice disturbance to control the properties of intrinsic localized modes (ILMs). The application of a specific inhomogeneous field destroys a driver-locked ILM, while the same operation can create an ILM if initially no-ILM exists. Logic states "1" and "0" correspond to "present" or "absent" ILM.

Visualizing intrinsic localized modes with a nonlinear micromechanical array

Micromechanical cantilever arrays provide the opportunity to visualize the nonlinear excitations of a discrete nonlinear system in real time. Both stationary and moving localized nonlinear excitations can be produced either by driving the system at a frequency outside the plane wave spectrum or by driving the system at a frequency within the small amplitude dispersion curve range. To see these modes the tips of the cantilevers are imaged on a 1D CCD camera. The brightness of the image depends on the oscillation amplitude of the cantilever, so that a distribution of amplitudes in the array can be recorded as a function of position and time. Both the stationary and traveling excitations have been successfully simulated using a nonlinear lumped element lattice model. The former ILM can appear in any size lattice while the latter requires a low density of modes for the formation of smoothly running excitation.

Driven Localized Excitations in the Acoustic Spectrum of Small Nonlinear Macroscopic and Microscopic Lattices

Both bright and dark traveling, locked, intrinsic localized modes (ILMs) have been generated with a spatially uniform driver at a frequency in the acoustic spectrum of a nonlinear micromechanical cantilever array. Complementary numerical simulations show that a minimum density of modes, hence array size, is required for the formation of such locked smoothly running excitations. Additional simulations on a small 1D antiferromagnetic spin system are used to illustrate that such uniformly driven running ILMs should be a generic feature of a nanoscale atomic lattice.

Investigation of micromechanical cantilever sensors with microfocus grazing incidence small-angle x-ray scattering

Micromechanical cantilever arrays coated with polymer brushes are an alternative to traditional chemical sensors. A critical parameter for the sensor sensitivity is the coating quality, and small changes in the coating uniformity generate a different behavior of the sensors. Microfocus grazing incidence small-angle x-ray scattering proved to be a sensitive tool to characterize coating quality, enabling a structural and chemical coating analysis.

Thermal contributions to the bending of bimaterial cantilever sensors

The thickness dependent contribution of thermal expansion and surface potential to the thermal response behavior of polymer coated micromechanical cantilevers is investigated. Polystyrene films in a thickness range of 2–150nm are used as coatings on silicon micromechanical cantilever arrays. Depending on coating thickness, either thermal expansion or interfacial tension dominates the response. For thick films we obtain a thermal expansion coefficient of 2.3×10−5±1.0×10−5°C−1 for the polystyrene coating. Using this value a temperature coefficient of interfacial tension of −50×10−5±14×10−5Jm−2°C−1 is determined for the silicon oxide/polystyrene interface. This establishes a method to measure the temperature coefficient of interfacial tension at solid/solid interfaces.

Conformational Change of Bacteriorhodopsin Quantitatively Monitored by Microcantilever Sensors

Bacteriorhodopsin proteoliposomes were used as a model system to explore the applicability of micromechanical cantilever arrays to detect conformational changes in membrane protein patches. The three main results of our study concern: 1), reliable functionalization of micromechanical cantilever arrays with proteoliposomes using ink jet spotting; 2), successful detection of the prosthetic retinal removal (bleaching) from the bacteriorhodopsin protein by measuring the induced nanomechanical surface stress change; and 3), the quantitative response thereof, which depends linearly on the amount of removed retinal. Our results show this technique to be a potential tool to measure membrane protein-based receptor-ligand interactions and conformational changes.

Colloquium: Nonlinear energy localization and its manipulation in micromechanical oscillator arrays

It has been known for some time that nonlinearity and discreteness play important roles in many branches of condensed-matter physics as evidenced by the appearance of domain walls, kinks, and solitons. A recent discovery is that localized dynamical energy in a perfect nonlinear lattice can be stabilized by the lattice discreteness. Intrinsic localized modes (ILMs) are the resulting signature. Their energy profiles resemble those of localized modes at defects in a harmonic lattice but, like solitons, they can move. ILMs have been observed in macroscopic arrays as diverse as coupled Josephson junctions, optical waveguides, two-dimensional nonlinear photonic crystals, and micromechanical cantilevers. Such dynamically driven localized modes are providing a new window into the underlying simplicity of nonequilibrium dynamics. This Colloquium surveys the studies of ILMs in micromechanical cantilever arrays. Because of the ease of sample fabrication with silicon technology and the intuitive optical visualization techniques, these experiments are able to demonstrate the general nature and properties of dynamical energy localization while at the same time providing new information on ILM generation, locking, pinning, and interaction with impurities.

Micromechanical mass sensors for biomolecular detection in a physiological environment

Micromechanical cantilever arrays are used to measure time-resolved adsorption of tiny masses based on protein-ligand interactions. Here, streptavidin-biotin interactions are investigated in a physiological environment. A measurement method is introduced using higher flexural modes of a silicon cantilever in order to enhance the sensitivity of mass detection. Modeling the cantilever vibration in liquid allows the measurement of absolute mass changes. We show time-resolved mass adsorption of final 7+/-0.7 ng biotinylated latex beads. The sensitivity obtained is about 2.5 pg/Hz measuring at a center frequency of 750 kHz.

Micromechanical cantilever array sensors for selective fungal immobilization and fast growth detection

We demonstrate the use of micromechanical cantilever arrays for selective immobilization and fast quantitative detection of vital fungal spores. Micro-fabricated uncoated as well as gold-coated silicon cantilevers were functionalized with concanavalin A, fibronectin or immunoglobulin G. In our experiments two major morphological fungal forms were used--the mycelial form Aspergillus niger and the unicellular yeast form Saccharomyces cerevisiae, as models to explore a new method for growth detection of eukaryotic organisms using cantilever arrays. We exploited the specific biomolecular interactions of surface grafted proteins with the molecular structures on the fungal cell surface. It was found that these proteins have different affinities and efficiencies to bind the spores. Maximum spore immobilization, germination and mycelium growth was observed on the immunoglobulin G functionalized cantilever surfaces. We show that spore immobilization and germination of the mycelial fungus A. niger and yeast S. cerevisiae led to shifts in resonance frequency within a few hours as measured by dynamically operated cantilever arrays, whereas conventional techniques would require several days. The biosensor could detect the target fungi in a range of 10(3) - 10(6) CFUml(-1). The measured shift is proportional to the mass of single fungal spores and can be used to evaluate spore contamination levels. Applications lie in the field of medical and agricultural diagnostics, food- and water-quality monitoring.

Direct observation of the discrete character of intrinsic localized modes in an antiferromagnet

In a strongly nonlinear discrete system, the spatial size of an excitation can become comparable to, and influenced by, the lattice spacing. Such intrinsic localized modes (ILMs)--also called 'discrete breathers' or 'lattice solitons'--are responsible for energy localization in the dynamics of discrete nonlinear lattices. Their energy profiles resemble those of localized modes of defects in a harmonic lattice but, like solitons, they can move (although, unlike solitons, some energy is exchanged during collisions between them). The manipulation of these localized energy 'hotspots' has been achieved in systems as diverse as annular arrays of coupled Josephson junctions, optical waveguide arrays, two-dimensional nonlinear photonic crystals and micromechanical cantilever arrays. There is also some evidence for the existence of localized excitations in atomic lattices, although individual ILMs have yet to be identified. Here we report the observation of countable localized excitations in an antiferromagnetic spin lattice by means of a nonlinear spectroscopic technique. This detection capability permits the properties of individual ILMs to be probed; the disappearance of each ILM registers as a step in the time-dependent signal, with the surprising result that the energy staircase of ILM excitations is uniquely defined.

ZEOLITE AND POLYMER FILM BIO-CHEMICAL MEMS SENSORS

International Journal of Computational Engineering ScienceVol. 04, No. 02, pp. 239-242 (2003) BioMEMS and MicrofluidsNo AccessZEOLITE AND POLYMER FILM BIO-CHEMICAL MEMS SENSORSYIPING HUANG, JILIE KONG, JIA ZHOU, YINGCAI LONG, PO LI, HAIFEN XIE and MINHANG BAOYIPING HUANGDepartment of Microelectronics, 220 Handan Road, Shanghai, China, 200433, P. R. China Search for more papers by this author , JILIE KONGChemistry Department, Fudan University, 220 Handan Road, Shanghai, China, 200433, P. R. China Search for more papers by this author , JIA ZHOUDepartment of Microelectronics, 220 Handan Road, Shanghai, China, 200433, P. R. ChinaChina University of Science and Technology, Jinshan, 1000Xuefu Road, China, 201512, P. R. China Search for more papers by this author , YINGCAI LONGChemistry Department, Fudan University, 220 Handan Road, Shanghai, China, 200433, P. R. China Search for more papers by this author , PO LIDepartment of Microelectronics, 220 Handan Road, Shanghai, China, 200433, P. R. China Search for more papers by this author , HAIFEN XIEDepartment of Microelectronics, 220 Handan Road, Shanghai, China, 200433, P. R. ChinaChina University of Science and Technology, Jinshan, 1000Xuefu Road, China, 201512, P. R. China Search for more papers by this author and MINHANG BAODepartment of Microelectronics, 220 Handan Road, Shanghai, China, 200433, P. R. China Search for more papers by this author https://doi.org/10.1142/S1465876303000983Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractIn recent years, considerable interest has increased on the use of chemical and biomedical sensor arrays in conjunction with pattern recognition analysis for the identification of gases, liquid system or the determination of antigen-antibody interaction. Some sensor arrays technologies based on work carried out at Fudan University (China) are presented including (1) microcantilevers in resonating mode (2) polymer-based sensor arrays (3) capacitive immunosensor arrays.Keywords:sensor arraysmicrocantileverzeolitepolymer-based sensorgas sensorimmunosensor References H. P. Langet al., Analytica Chimica Acta 393, 59 (1999). Crossref, Google ScholarGuo-qing Guo and Ying-Cai Long, Separation and Purification Technology 24, 507 (2001). Crossref, Google ScholarY.-C. Long, H.-W. Jiang and H. Zeng, Langmuir 13, 4094 (1997). Crossref, Google ScholarE. Tsifrinaet al., Am. J. of Pathol. 155(5), 1625 (1999). Crossref, Google Scholar L. Castera, D. J. Hartmann, F. Chapel, C. Guettier, F. Mal, T. Lons and J. P. Richardet, Serum laminin and type IV collagen are accurate markers of histologically severe alcoholic hepatitis in patients with cirrhosis, J HEPATOL 32(3)(2000) 412-418 [1] H. P. Lang, M. K. Baller, et al, An artificial nose based on a micromechanical cantilever array, Analytica Chimica Acta 393 (1999) pp. 59-65 . Google Scholar FiguresReferencesRelatedDetails Recommended Vol. 04, No. 02 Metrics History Keywordssensor arraysmicrocantileverzeolitepolymer-based sensorgas sensorimmunosensorPDF download

Study of intrinsic localized vibrational modes in micromechanical oscillator arrays.

Intrinsic localized modes (ILMs) have been observed in micromechanical cantilever arrays, and their creation, locking, interaction, and relaxation dynamics in the presence of a driver have been studied. The micromechanical array is fabricated in a 300 nm thick silicon-nitride film on a silicon substrate, and consists of up to 248 cantilevers of two alternating lengths. To observe the ILMs in this experimental system a line-shaped laser beam is focused on the 1D cantilever array, and the reflected beam is captured with a fast charge coupled device camera. The array is driven near its highest frequency mode with a piezoelectric transducer. Numerical simulations of the nonlinear Klein-Gordon lattice have been carried out to assist with the detailed interpretation of the experimental results. These include pinning and locking of the ILMs when the driver is on, collisions between ILMs, low frequency excitation modes of the locked ILMs and their relaxation behavior after the driver is turned off.

Biased micromechanical cantilever arrays as optical image memory.

We show that an array of optically actuated biased cantilevers can work as an optical data storage, able to encode data stored as arrays of optical pixels (images). Each of these optical pixels can, in addition, have a predetermined pixel depth, expressed as a certain number of gray levels. This new optical memory is able to work at a data rate of approximately 7 GB/s for an image with 128 x 128 pixels.

An artificial nose based on a micromechanical cantilever array

A novel chemical sensor based on a micromechanical array of silicon cantilevers is presented. Chemical reactions are transduced by sensitization of cantilevers with coatings such as metals, self-assembled monolayers, or polymers into a mechanical response. This is read out using an optical beam-deflection technique by a sequential readout scheme. Reference cantilever sensors permit subtraction of background signals (differential measurement). Coating of each cantilever sensor with a different sensitive layer allows operation of the array-device as a new form of chemical nose. Detection of hydrogen, primary alcohols, natural flavors, and water vapor is demonstrated. We show that the magnitude of sensor response is proportional to the amount of analyte present.

A chemical sensor based on a micromechanical cantilever array for the identification of gases and vapors

We have built and operated a novel setup for the characterization and identification of gases or vapors based on sequential position readout via a beam-deflection technique from a microfabricated array of eight cantilever-type sensors. Each of the cantilevers can be coated on one side with a dif- ferent sensor material to detect specific chemical interactions. We demonstrate that disturbances from vibrations and turbu- lent gas flow can be effectively removed in array sensors by taking difference signals with reference cantilevers. For ex- ample, H2 can be detected by its adsorption on a Pt-coated sensor because a change in surface stress causes a static bending of the sensor. The diffusion of various alcohols into polymethylmethacrylate induces resonance frequency shifts in a dynamic measuring mode and bending in the static mode, which allows one to distinguish between the various alcohols. Sensor devices for detection of gases and vapors via spe- cific coatings are gradually gaining importance in chemistry, materials science, and biochemistry owing to the increas- ing demand for detection of analytes at monolayer coverage. A field of increasing interest is the construction of so-called electronic noses capable of discerning different odors via a typical response pattern of the receptor layers to an analyte. Most devices currently applied involve square centimeter- sized detection areas and comparatively large gas volumes (typically 50- 1000 cm 3 ) resulting in relatively long response