Search

This paper is devoted to investigating the propagation speed and direction of the bistable traveling wave for the Lotka–Volterra competition model with bistable nonlinearity. A range-estimation of the bistable wave speed is provided by comparing the bistable traveling wave with the monostable ones in the system. Comparison theorems on the speed and direction of wave propagation are first established by the method of upper and lower solutions. Through the construction of novel upper and lower solutions, we obtain some new criteria that explicitly determine the speed sign of the bistable traveling wave. Based on these results, we can predict which species will win in the competition for the same resources.

A theoretical model is proposed that describes the lasing dynamics in a gas ring laser (GRL) with coupled cavities. The conditions are found under which spontaneous phase symmetry of counterpropagating waves is broken in the GRL with an antiphase optical coupling of the cavities. It is shown that in the case of spontaneous phase symmetry breaking, two branches appear on the GRL frequency characteristic. In some region of frequency nonreciprocity of a ring cavity, both branches can exist under the same conditions. In this case, radiation bistability appears in the GRL, and hysteresis phenomena can be observed.

We study the existence of monotone wavefronts for a general family of bistable reaction–diffusion equations with delayed reaction term g. Differently from previous works, we do not assume the monotonicity of with respect to the delayed variable that does not allow to apply the comparison techniques. Thus our proof is based on a variant of the Hale–Lin functional-analytic approach to heteroclinic solutions of functional differential equations where Lyapunov–Schmidt reduction is done in appropriate weighted spaces of C 2-smooth functions. This method requires a detailed analysis of associated linear differential operators and their formal adjoints. For two different types of -unimodal functions , we establish the existence of a maximal continuous family of bistable monotone wavefronts. Depending on the type of unimodality (equivalently, on the sign of the wave speed), two different scenarios can be observed for the obtained bistable waves: (1) independently on the size of delay, each bistable wavefront is monotone; (2) wavefronts are monotone for moderate values of delays and can oscillate for large delays.

In this paper, we present an input-independent energy harvesting mechanism exploiting topological solitary waves. This class of medium transforming solitons, or transition waves, entails energy radiation in the form of trailing phonons in discrete bistable lattices. We observe numerically and experimentally that the most dominant frequencies of these phonons are invariant to the input excitations as long as transition waves are generated. The phonon energy at each unit cell is clustered around a single invariant frequency, enabling input-independent resonant harvesting with conventional energy transduction mechanisms. The presented mechanism fundamentally breaks the link between the unit cell size and the metamaterial’s operating frequencies, offering a broadband solution to energy harvesting that is particularly robust for low-frequency input sources. We further investigate the effect of lattice discreteness on the energy harvesting potential, observing two performance gaps and a topological wave harvesting pass band where the potential for energy conversion increases almost monotonically. The observed frequency-invariant phonons are intrinsic to the discrete bistable lattices, enabling broadband energy harvesting to be an inherent metamaterial property.

In this article, we proposed a new way to achieve monostable and bistable characteristics of composite layers based on liquid crystal elastomer (LCE). A smart trilayer composite structure is fabricated using LCE and acrylic elastomer, which can have several morphologies. It keeps flat at room temperature and can deform into a monostable saddle or bistable cylinder surface in response to simple temperature changes. The reversible deformation can be controlled through two parameters including geometrical size and actuation strain. The LCE can be programmed to generate different actuation strains by different formulas during synthesis or different mechanical stretches during UV radiation. The deformed morphology for different sample sizes and actuation strain is calculated using Finite element simulation. By comparison with the experimental results, we confirm that the phenomena can be captured through numerical simulations. Furthermore, to have a quantitative understanding, we use numerical simulation to calculate the deformation of the composite structure by tuning these two parameters and give a morphological portrait illustrating the relationship between the deformed shape and control parameters.

Soft bending actuators, as one of the most important components of soft robotics, have attracted significantly increasing attention due to their robustness, compliance, inherent safety, and ease of manufacture. However, the key disadvantages can be the low output force, slow response speed, large deformation and vibration, which can potentially be addressed by introducing a bistable mechanism enabled by a prestressed steel shell. This work proposes a novel soft actuator with bistable property, which can maintain the predefined initial state and enhance bending motion at the corresponding stable state. A novel dual-actuation mechanism, which utilises pneumatic pressure for closing and tendon-driven for opening process, is proposed for autonomous transition between both states, and for a fast response. Mathematical model is proposed and compared with the experimental result for triggering pressure, which serves as a threshold to activate the transition of the stable state. Experimental results also indicate that closing and opening speeds are enhanced by 9.82% and more than ten times, respectively, as compared with the existing pneumatic bistable reinforced actuator design. Mathematical and experimental results suggest that a programmable bending angle at the second stable state can also be achieved by adjusting the preset tendon extension. The tendon arrangement also acts as a passive damping mechanism to reduce the oscillation while closing. The damping ratio is increased by more than four times, indicating that the oscillation decay is significantly accelerated for quick stabilization. Finally, a three-finger soft gripper is developed based on the proposed actuator design, which demonstrates promising performance in grasping objects with various shapes and sizes. The experimental results also show that the proposed bistable gripper can grasp the object with a weight up to 2067 g, which is more than 17 times heavier than that of three actuators.

We address exotic optical response of a planar metasurface comprising a monolayer of regularly spaced quantum three-level emitters with a doublet in the ground state (the so-called Λ-emitters). All emitters are coupled by the retarded dipole field which depends on the current state of all emitters. This coupling introduces a feedback into the system. Complex interplay of the latter with the intrinsic nonlinearity of a three-level system results in several remarkable effects in the monolayer’s optical response, such as multistability, self-oscillations, and chaos. The peculiarity of the considered system is that some of the predicted nonlinear effects manifest themselves at very low excitation field intensities (on the order of 1 W/cm2), which is advantageous for possible applications: the monolayer can operate as a perfect reflector, a bistable mirror, and a THz or noise generator. It is argued therefore that the proposed system is a promising candidate for a building block for various photonic nano-devices.

Triboelectric energy harvesting has emerged as a promising route to scavenge ambient mechanical energy for cost-effective, clean and sustainable electricity. Disc-shaped triboelectric energy harvesters are suitable for two kinds of mechanical energy sources: continuous rotation and vibration. A majority of current studies about disc-shaped triboelectric energy harvesters focus on scavenging energy in continuous rotation, but there is a lack of investigations on angular vibration, especially in structural dynamics. In this work, a new disc-shaped triboelectric energy harvester with a bistable mechanism enabled by two repulsive magnets is developed for harvesting vibration energy. There are two discs in the harvester, one stationary and the other undergoing angular oscillation. Both have segmented triboelectric films on their contact surfaces. The magnetic bistable mechanism is utilized for the first time in a disc-shaped triboelectric energy harvester for efficiency enhancement. A comprehensive theoretical model coupling both structural dynamic and electric dynamic domains is established. A comparison between the coupled and uncoupled models reveals that the ET between electrodes can be ignored. Numerical simulations are carried out to investigate the effect of the potential wells due to the two magnets, basins of attractors and the influence of damping from the perspective of structural dynamics. A prototype is fabricated for experimental investigations, which demonstrate that the harvester with the bistable mechanism can achieve a better performance than the corresponding harvester without the bistable mechanism, and the output voltage of the harvester increases with the increase of excitation amplitude. Theoretical and experimental comparisons about the electric outputs between the triboelectric films with different segmentation structures reveal that increasing the number of sectors on the films effectively improves the harvesting efficiency. This work establishes a link between the structural dynamics and electric dynamics for the vibration-based disc-shaped triboelectric energy harvester, providing guidelines for its design and fabrication.

Bistable nanomagnets store a binary bit of information. Exchange coupled nanomagnets can increase the thermal stability at low dimensions. Here we show that the antiferromagnetically (AFM) coupled nanomagnets can be highly stable at low dimensions than that of the ferromagnetically (FM) coupled nanomagnets. By solving stochastic Landau-Lifshitz-Gilbert equation of magnetization dynamics at room temperature, we analyze the stability of the exchange coupled nanomagnets in the presence of correlated, uncorrelated, and anti-correlated noise. The results show that the correlated noise can make the stability of the AFM coupled nanomagnets very high. Such finding will lead to very high-density non-volatile storage and logic devices in our future information processing systems.

We theoretically study the polariton multistability in a solid state based optomechanical resonator embedded with a quantum well and aχ(2)second order nonlinear medium. The excitonic transition inside the quantum well is strongly coupled to the optical cavity mode. The polariton formed due to the mixing of cavity photons and exciton states are coupled to the mechanical mode which gives rise to the bistable behavior. A transition from bistability to tristability occurs in the presence of a strongχ(2)nonlinearity. Switching between bistability and tristability can also be controlled using exciton-cavity and optomechanical coupling making the system highly tunable. Tristability appears at low input power making it a suitable candidate for polaritonic devices which requires low input power.

Owing to the enormously enhanced oscillating wave, a minute variation of the incident light intensity will give rise to a change in the dielectric constant of the Kerr nonlinear medium and lead to a bistable reflection with an ultra-low threshold intensity, which is closely related to the angle of incidence and the thickness of the Kerr nonlinear medium. The criterion for the existence of optical bistability is derived. Our bistability scheme is simple and not limited to the TM-polarization.

The social reinforcement mechanism, which characterizes the promoting effects when exposed to multiple sources in the social contagion process, is ubiquitous in information technology ecosystems and has aroused great attention in recent years. While the impacts of social reinforcement on single-layer networks are well documented, extension to multilayer networks is needed to study how reinforcement from different social circles influences the spreading dynamics. To this end, we incorporate multilayer social reinforcement into an ignorant–spreader–ignorant model on multiplex networks. Our theoretical analysis combines the pairwise method and mean-field theory and agrees well with large-scale simulations. Surprisingly, we find this complex social contagion mechanism triggers the emergence of bistability phenomena, where extinction and outbreak states coexist. In particular, the hysteresis loop of stationary prevalence occurs in this bistable region, explaining why the fight against the spread of rumors is protracted and difficult in modern society. Further, we show that the final state of bistable regions depends on the initial density of adopters, the critical value of which decreases as the contagion transmissibility or the multilayer reinforcement increases. In particular, we highlight two possible conditions for the outbreak of social contagion: to possess large contagion transmissibility, or to possess a large initial density of adopters with strong multilayer reinforcement. Our results unveil the non-negligible power of social reinforcement on multiplex networks, which sheds lights on designing efficient strategies in spreading behaviors such as marketing and promoting innovations.

Coupling-induced logical stochastic resonance (LSR) can be observed in a noise-driven coupled bistable system where the behaviors of system can be interpreted consistently as a specific logic gate in an appropriate noise level. Here constant coupling is extended to time-varying coupling, and then we investigate the effect of time-varying coupling on LSR in a periodically driven coupled bistable system. When coupling intensity oscillates periodically with the same frequency with periodic force or relatively high frequency, the system successfully yields the desired logic output. When coupling intensity oscillates irregularly with phase disturbance, large phase disturbance reduces the area of optimal parameter region of coupling intensity and response speed of logic devices. Although the system behaves as a desired logic gate when the frequency of time-periodic coupling intensity is precisely equal to that of periodic force, the desired logic gate is not robust against tiny frequency difference and phase disturbance. Therefore, periodic coupling intensity with high frequency ratio is an optimal option to obtain a reliable and robust logic operation.

In resonantly pumped polariton superfluids we recently explored a new regime based on the bistability of the polariton system to enhance the propagation of polariton fluids up to macroscopic distances. This technique together with an all-optical imprinting method allowed the generation and control of various topological excitations such as quantized vortices and dark solitons. The flexibility and scalability of the new experimental scheme opens the way to the systematic study of quantum turbulence in driven dissipative quantum fluids of light. In this article we review the basic working principles of the bistability enhanced propagation and of the imprinting technique and we discuss the main achieved results as well as the most promising future research directions., Review, 12 pages, 16 figures

We consider an analytically tractable switching model that is a simplification of a nonlocal, nonlinear reaction–diffusion model of population growth where we take the source term to be piecewise linear. The form of this source term allows us to consider both the monostable and bistable versions of the problem. By transforming to a traveling frame and choosing specific kernel functions, we are able to reduce the problem to a system of algebraic equations. We construct solutions and examine the propagation speed and monotonicity of the resulting waves.

The aim of this paper is to introduce tunable continuous-stable metamaterials with reversible thermomechanical memory operations by four-dimensional (4D) printing technology. They are developed based on an understanding on glassy-rubbery behaviors of shape memory polymers and hot/cold programming derived from experiments and theory. Fused decomposition modeling as a well-known 3D printing technology is implemented to fabricate mechanical metamaterials. They are experimentally tested revealing elastic-plastic and hyper-elastic behaviors in low and high temperatures at a large deformation range. A computational design tool is developed by implementing a 3D phenomenological constitutive model coupled with a geometrically non-linear finite element method. Governing equations are then solved by an elastic-predictor plastic-corrector return map procedure along with the Newton-Raphson and Riks techniques to trace non-linear equilibrium path. A tunable reversible mechanical metamaterial unit with bistable memory operations is printed and tested experimentally and numerically. By a combination of cold and hot programming, the unit shows potential applications in mimicking electronic memory devices like tactile displays and designing surface adaptive structures. Another design of the unit shows potentials to serve in designing self-deployable bio-medical stents. Experiments are also conducted to demonstrate potential applications of cold programming for introducing recoverable rolling-up chiral metamaterials and load-resistance supportive auxetics.

The use of piezoelectric energy harvester to convert environmental low-frequency vibration energy into electrical energy has become a research hotspot in the field of new energy. However, the piezoelectric energy harvester developed at present has high natural frequency and narrow energy trapping band, which has become one of the main reasons restricting the application of this technology. To solve this problem, based on the principle of nonlinear three degrees of freedom, this paper proposes a three-degree-of-freedom bistable piezoelectric energy trapping method. Firstly, the three-degree-of-freedom bistable energy capture method is modeled, and the energy capture frequency and nonlinear force of the model are derived; then use COMSOL software to simulate the model. The simulation results prove that this model not only reduces the natural frequency of the piezoelectric energy harvester, but also the introduced nonlinear magnetic force significantly broadens the energy trapping band. Finally, the actual measurement and comparative analysis of the proposed method prove the effectiveness of the proposed method.

In this paper, by utilizing the transfer matrix method, a structure composed of one-dimensional (1D) periodic multilayer dielectrics, InSb, and nonlinear material is proposed to investigate the behavior of the spin Hall effect of light (SHEL) and its nonreciprocity and bistable features. The results demonstrate that, as the light intensity increases, the reflection coefficients under both TM and TE waves have a bistable phenomenon, and the points of both horizontal and vertical displacements are consistent with the regions where reflection is close to 0. Furthermore, to make our study complete, the thicknesses of the nonlinear and InSb layers are adjusted to study the effects on the performance of SHEL, and it can be found that, with the escalation of the thicknesses of the nonlinear and InSb layers, all the points of displacements are shifting to the direction of the angle. Besides, all parameters demonstrate the phenomenon of nonreciprocity. This research supplies meaningful guidelines for some optical instruments, such as light intensity sensors.

This paper presents a novel bistable vibration energy harvester with an elastic boundary (BVEH_EB). The bistable nonlinearity of the BVEH_EB is realized by an inclined spring, which could induce a large-amplitude inter-well response to pursue high harvesting efficiency. The elastic boundary brings additional dynamic coupling with the inclined spring to reduce the depth of the potential energy well, which could enhance the inter-well response. The bifurcation responses in terms of different parameters such as the magnet mass, the inclined spring stiffness, the excitation frequency, and the excitation amplitude are numerically investigated. Abundant nonlinear phenomena, such as intra-well oscillation, inter-well oscillation, chaos, etc., are observed. The design guidelines of the BVEH_EB are developed, which could provide a novel harvesting method.

Bistable crystal cover relays are widely used in aerospace and other electronic systems due to their outstanding resistance to mechanical environment. However, the bistable crystal cover relays have a complicated structure and are difficult to design and debug. There are still quality problems in this kind of relay such as low electromagnetic efficiency, small commissioning margin and large product dispersion. This paper aims at solving the problems of poor anti-interference of output characteristics caused by the imperfection of the reliability design. The finite element model of the electromagnetic system of the relay was established by using FLUX software and the electromagnetic characteristics of the relay were simulated and analyzed firstly. By comparing with the actual measurement, verified the correctness of the simulation results and guaranteed the accurate calculation of the experimental research. On the basis, this paper adopts the robust design method proposed by Taguchi Genichi to optimize the product parameters and tolerances of the relays. At present, the research conclusion is applied to the improvement of a certain type of aerospace electromagnetic relay. This paper provides necessary research means and basis for the robustness design of aerospace electromagnetic relay. The related methods and technologies can also be applied to the design of other electrical products.

Unsymmetric composite laminates exhibit two stable configurations at room temperature after being cured at elevated temperature. Bistability of cross-ply laminates is due to the presence of residual strains imparted during the curing process. A simple snap-through process can be used to switch from one stable shape to another. The amount of snap-through force required for attaining the other stable shape depends on the total strain energy of the laminate in the first cured shape. Bistable shapes of the conventional square laminates are in the same energy level, which means the stable configurations are equally stable and results in equal snap-through and snap-back forces. By tailoring the energy levels of stable shapes, snap-through and snap-back forces can be varied. From various studies in the past, it is observed that bistable laminates have enormous potential for morphing applications. In some of the practical applications, one may require stable shapes at different energy levels, with unequal snap-through and snap-back energies for the shape transition. This study aims to tailor the energy levels of bistable shapes of the square laminate by varying the thickness of individual layers in the considered [0/90] square laminates. A detailed parametric study is performed in commercially available finite element software. It is concluded from the study that individual lamina thickness has a noticeable influence on the bistability of cross-ply laminates.

A model is proposed in the framework of classical electrostatics to describe the behavior of an adsorbed polar molecule near the plane interface between two insulators under the action of an external electrostatic field. The molecule is considered as a permanent point dipole that polarizes the interface and interacts with it through electrostatic image forces. The latter and the applied field try to reorient the dipole in a competitive manner. The system behavior turns out to be rather complicated: it may show a bistable character with a hysteresis (a switch). Such a switch can serve as an element in a memory network made of adsorbed molecules.

Bistable elements are candidate structures for the evolving field of MEMS-based no-power event-driven sensors. In this paper, we present a strategy for producing bistable elements and investigate two compatible bilayer material systems for their realization using MEMS technology. Both bilayer systems leverage thermally-grown silicon dioxide as the principal stress-producing layer and a second material (either polyimide or aluminum) as the main structural layer. Arrays of buckled circular diaphragms, ranging in diameter from 100 μm to 700 μm in 50 μm increments, were fabricated and their performances were compared to modeled and FEA-simulated results. In all cases, the diaphragms buckled when DRIE-released as expected, and their buckled experimental heights were within 9.1% of the theory and 1.8% of the FEA prediction. Interestingly, the smaller diameter structures exhibited a directional bias which we investigate and forecast using FEA. These bistable mechanical elements have the ability to serve as building blocks for no-power threshold-driven smart switches. New contributions to the field include: (a) introduction of a new bistable material system made from aluminum and compressive oxide, (b) investigation of diaphragm diameter size as it related to the phenomena of bistability versus non-bistability, (c) FEA analysis of the critical transition between bistability and non-bistability, and (d) introduction of the ‘dome factor’ term to describe dome quality.

A scheme for switching of the optical bistability (OB) and multi-stability (OM) in a dielectric slab doped with a three-level ladder-configuration n-doped semiconductor quantum well is simulated. It is shown that the bistable behavior of the system in dielectric slab can be controlled via amplitude or relative phase of applied fields. This optical system may provide some new possibilities for test the switching process.

This paper presents a centrifugal softening impact energy harvester with the bistability using flextensional transducers. The bistability is firstly demonstrated to further enhance the advantages of the centrifugal softening effect in improving the impact energy output at low rotational speeds. In the harvester, two flextensional transducers are impacted by a centrifugal softening driving beam, which is experiencing the magnetic repulsive force at the same time. The flextensional transducers are adopted for their high electromechanical coupling coefficient and robustness under the large impact force. A theoretical model is built and validated by experiments. Experimental results show that the bistable harvester can generate higher energy output than the non-linear monostable and linear harvesters at the rotational speed ranging from 60 rpm to 360 rpm and a certain clearance of 1.07 mm. Its maximum instantaneous power and RMS voltage at 60 rpm are respectively increased by 323.1% and 184.3% compared with the non-linear monostable one, and 899.9% and 304.2% compared with the linear one. Such significant improvement cannot be achieved by changing the clearance in the linear harvester while it can be achieved by adding the bistability. Therefore, our proposed method facilitates the effective energy harvesting from widely-distributed low-speed rotations.

We theoretically explore optical bistability for the possible signature of all-optical switching and their performance in a hybrid quantum optomechanical system comprising of two semiconductor microcavities coupled optically. One of the cavity is driven by an external amplitude-modulated pump laser while the second cavity, which contains a quantum dot, is indirectly driven by light transmitted from the first cavity and a transverse optical field. The generated bistable behavior due to optomechanical nonlinearity shows a typical optical switching behavior and it can be controlled by changing the laser power, QD cavity coupling, modulating amplitude/frequency and the optomechanical coupling. A clear signature of energy exchange between the mechanical and optical modes is visible from the mechanical displacement spectrum. These results suggest that the present system can be used in sensitive optical switches and optical sensors.

Cytoplasmic dynein is an important molecular motor involved in the transport of vesicular and macromolecular cargo along microtubules in cells, often in conjunction with kinesin motors. Dynein is larger and more complex than kinesin and the mechanism and regulation of its movement is currently the subject of intense research. While it was believed for a long time that dynein motors are relatively weak in terms of the force they can generate, recent studies have shown that interactions with regulatory proteins confer large stall forces comparable to those of kinesin. This paper reports on a theoretical study which suggests that these large stall forces may be the result of an emergent, ATP dependent, bistability resulting in a dynamic catch-bonding behavior that can cause the motor to switch between high and low load-force states.

Benefiting from the latest experiment of nonlinearity in cavity magnon polaritons due to the magnetocrystalline anisotropy in the yttrium iron garnet (YIG) crystal, we theoretically propose a cavity magnonics model that can be used to study the bistable behaviors by changing the coupling strength, which presents the rich and interesting phenomena. In the case of resonance, the critical driving powers of the upper and lower polariton modes have the smaller values for the larger coupling strength but the larger values for the smaller coupling strength. In addition, the upper and lower polariton modes show the repulsive and attractive features, respectively, when the derivative of the coupling strength with respect to the position of the YIG sphere changes from positive to negative. Especially, the bistability of the lower polariton mode disappears when the driving power is strong enough. Our research broadens the means of manipulation of nonlinearity in cavity magnon system, which provides a promising application for cavity spintronics and information processing.

We study theoretically a driven dissipative one-dimensional XXZ spin$-1/2$ chain with dipole coupling and a tunable strength of the Ising and XY interaction. Within a mean-field approximation, we find a rich phase diagram with uniform, spin density wave, antiferromagnetic and oscillatory phases, as well as regions of phase bistability. We study the phase diagram of small quantum systems using exact diagonalisation, and compare the results to the mean-field theory. We find that while expectation values only capture the uniform phases of the mean-field theory, fluctuations about these expectation values give signatures of spatially non-uniform phases and bistabilities. We find these signatures for all ratios of the Ising to XY interaction, showing that they appear to be general features of spin$-1/2$ systems, 9 pages, 7 figures

The interplay of small, noncoding microRNAs (miRNAs), mRNAs and proteins plays crucial roles in almost all cellular processes. MiR-124, widely known as a memory-related miRNA, can regulate LTM by binding to the mRNA of CREB1 stimulated with 5-HT. In this paper, we establish a regulatory network model of CREB1 and miR-124 stimulated by 5-HT, in which miR-124 inhibits CREB1, which in turn enhances miR-124. Our model validates three protocols based on 5-HT in experiments on the induction of LTM in Aplysia. A steady-state analysis and numerical bifurcations of the abstracted system beyond memory formation, when the fast reaction has been in the equilibrium, can facilitate more abundant dynamical behaviors such as bistability and oscillation. The original system also exhibits bistability under appropriate feedback strengths, which is relevant to the mechanism of LTM formation. Furthermore, we specifically show a change in the transition from a reversible switch to an irreversible switch via bifurcations of the negative regulation of miR-124 on CREB1, which eventually maintains a high phosphorylated CREB1 level after initially elevated by 5-HT. These findings indicate that miR-124 provides an inhibitory constraint on long-term synaptic plasticity through the regulation of CREB1.

Based on the nonlocal strain gradient theory, a new nonlinear dynamic model for an arch micro resonator is developed in this paper. The governing nonlinear partial differential equations of the doubly clamped Euler–Bernoulli arch micro resonator are derived by employing Hamilton's principle. Electrostatic actuation and Casimir force are considered to provide the excitation of the micro resonator. By application of the Galerkin scheme, the nonlinear partial differential equation of dynamic motion of the micro resonator is discretized to the nonlinear ordinary differential equation with quadratic and cubic nonlinearities. Potential energy and bistability are investigated for the electrostatically actuated arch micro resonator. As an analytical approach, perturbation method is used to examine the nonlinear forced vibration behavior of the resonator. The frequency-response curves are obtained to study the effect of size-dependency on the amplitude of forced vibration of the arch micro resonator for the primary resonance.

As CMOS scaling limit is reached, no-charge based devices and non-equilibrium systems need to be investigated as alternative switching units. We present a non-volatile nanoelectromechanical switch with state variable mechanical positioning of a single-walled CNT bundle suspended over metal electrodes deposited in dry-etched trenches. The switch is fabricated using a single mask fabrication process followed by dielectrophoresis-based directed assembly of the CNT bundle. The design exhibits symmetric behavior with the same actuation voltage (

We propose a joint exponential function and Woods–Saxon stochastic resonance (EWSSR) model. Because change of a single parameter in the classical stochastic resonance model may cause a great change in the shape of the potential function, it is difficult to obtain the optimal output signal-to-noise ratio by adjusting one parameter. In the novel system, the influence of different parameters on the shape of the potential function has its own emphasis, making it easier for us to adjust the shape of the potential function. The system can obtain different widths of the potential well or barrier height by adjusting one of these parameters, so that the system can match different types of input signals adaptively. By adjusting the system parameters, the potential function model can be transformed between the bistable model and the monostable model. The potential function of EWSSR has richer shapes and geometric characteristics. The effects of parameters, such as the height of the barrier and the width of the potential well, on SNR are studied, and a set of relatively optimal parameters are determined. Moreover, the EWSSR model is compared with other classical stochastic resonance models. Numerical experiments show that the proposed EWSSR model has higher SNR and better noise immunity than other classical stochastic resonance models. Simultaneously, the EWSSR model is applied to the detection of actual bearing fault signals, and the detection effect is also superior to other models.