Resonant Behavior Research Articles

Verification and development of a metamaterial with large bandwidth smooth transmission properties for the thermal properties sensing of Xuan paper

Metamaterial sensors are widely used because of their rich resonance behaviors. However, due to the dependence on resonance properties, many metamaterial sensors are difficult to be applied in measurement of the stationary thermal properties of Xuan paper samples in a wide frequency range. Many important properties of Xuan paper samples are related to thermal resonance properties,. such as folding resistance, tensile strength, ink-run property, whiteness, dry heat and wet heat aging. Here, a metamaterial sensor with smooth transmission performance in the operating frequency band is designed and fabricated. In experiments, by increasing temperature, the time for the thermal response current of the Xuan paper samples to reach the peak value is significantly reduced, and the average peak value is increased. The heat conduction of the Xuan paper samples is increased and the thermal resistance is reduaced. When the thickness of the Xuan paper sample is gradually increased, the time required for the thermal response current to reach the peak value is gradually increased and the average peak value is decreased. When the concentration of alum gelatin solution applied on the surface of the Xuan paper sample is gradually increased, the corresponding thermal response current is enhanced, and the time required to reach the peak is significantly reduced. The results show that the metamaterial sensor can be used to measure the thermal properties of Xuan paper samples.

High-resolution spectroscopy of a single nitrogen-vacancy defect at zero magnetic field

We report a study of high-resolution microwave spectroscopy of nitrogen-vacancy (NV) centers in diamond crystals at and around zero magnetic field. We observe characteristic splitting and transition imbalance of the hyperfine transitions, which originate from level anti-crossings (LACs) in the presence of a transverse effective field. We use pulsed electron spin resonance spectroscopy to measure the zero-field spectral features of single NV centers for clearly resolving such LACs. To quantitatively analyze the magnetic resonance behavior of the hyperfine spin transitions in the presence of the effective field, we present a theoretical model, which describes the transition strengths under the action of an arbitrarily polarized microwave magnetic field. Our results are of importance for the optimization of the experimental conditions for the polarization-selective microwave excitation of spin-1 systems in zero or weak magnetic fields.

Metasurface supporting quasi-BIC for optical trapping and Raman-spectroscopy of biological nanoparticles.

Optical trapping combined with Raman spectroscopy have opened new possibilities for analyzing biological nanoparticles. Conventional optical tweezers have proven successful for trapping of a single or a few particles. However, the method is slow and cannot be used for the smallest particles. Thus, it is not adapted to analyze a large number of nanoparticles, which is necessary to get statistically valid data. Here, we propose quasi-bound states in the continuum (quasi-BICs) in a silicon nitride (Si3N4) metasurface to trap smaller particles and many simultaneously. The quasi-BIC metasurface contains multiple zones with high field-enhancement ('hotspots') at a wavelength of 785 nm, where a single nanoparticle can be trapped at each hotspot. We numerically investigate the optical trapping of a type of biological nanoparticles, namely extracellular vesicles (EVs), and study how their presence influences the resonance behavior of the quasi-BIC. It is found that perturbation theory and a semi-analytical expression give good estimates for the resonance wavelength and minimum of the potential well, as a function of the particle radius. This wavelength is slightly shifted relative to the resonance of the metasurface without trapped particles. The simulations show that the Q-factor can be increased by using a thin metasurface. The thickness of the layer and the asymmetry of the unit cell can thus be used to get a high Q-factor. Our findings show the tight fabrication tolerances necessary to make the metasurface. If these can be overcome, the proposed metasurface can be used for a lab-on-a-chip for mass-analysis of biological nanoparticles.

A coupled fractional-order system with fluctuating frequency and its application in bearing fault diagnosis

In this paper, a coupled fractional-order system with fluctuating frequency driven by different periodic signals under various damping strength is investigated. Firstly, based on the Shapiro-Loginov formula and Laplace transform method, the expressions for the output amplitude gain (OAG) of the two subsystems are derived and the resonant behaviors of particles are analyzed. The OAG exhibits various resonance behaviors in response to variations in system parameters, input signals and dichotomous noise, including parameter-induced stochastic resonance, bona-fide resonance and stochastic resonance. Especially, the average behavior of the two output signals is synchronized when two subsystems’ input signals and damping strengths are equal, which is verified in the numerical simulation. Finally, the proposed system is applied to the bearing fault diagnosis to evaluate its engineering application value. The results prove that the system is effective in diagnosing fault signals and has excellent performance.

Magnetoelastic Monitoring System for Tracking Growth of Human Mesenchymal Stromal Cells.

Magnetoelastic sensors, which undergo mechanical resonance when interrogated with magnetic fields, can be functionalized to measure various physical quantities and chemical/biological analytes by tracking their resonance behaviors. The unique wireless and functionalizable nature of these sensors makes them good candidates for biological sensing applications, from the detection of specific bacteria to tracking force loading inside the human body. In this study, we evaluate the viability of magnetoelastic sensors based on a commercially available magnetoelastic material (Metglas 2826 MB) for wirelessly monitoring the attachment and growth of human mesenchymal stromal cells (hMSCs) in 2D in vitro cell culture. The results indicate that the changes in sensor resonance are linearly correlated with cell quantity. Experiments using a custom-built monitoring system also demonstrated the ability of this technology to collect temporal profiles of cell growth, which could elucidate key stages of cell proliferation based on acute features in the profile. Additionally, there was no observed change in the morphology of cells after they were subjected to magnetic and mechanical stimuli from the monitoring system, indicating that this method for tracking cell growth may have minimal impact on cell quality and potency.

Dimension reduction of noisy interacting systems

We consider a class of models describing an ensemble of identical interacting agents subject to multiplicative noise. In the thermodynamic limit, these systems exhibit continuous and discontinuous phase transitions in a, generally, nonequilibrium setting. We provide a systematic dimension reduction methodology for constructing low-dimensional, reduced-order dynamics based on the cumulants of the probability distribution of the infinite system. We show that the low-dimensional dynamics returns the correct diagnostic properties since it produces a quantitatively accurate representation of the stationary phase diagram of the system that we compare with exact analytical results and numerical simulations. Moreover, we prove that the reduced order dynamics yields also the prognostic, i.e., time-dependent properties, as it provides the correct response of the system to external perturbations. On the one hand, this validates the use of our complexity reduction methodology since it retains information not only of the invariant measure of the system but also of the transition probabilities and time-dependent correlation properties of the stochastic dynamics. On the other hand, the breakdown of linear response properties is a key signature of the occurence of a phase transition. We show that the reduced response operators capture the correct diverging resonant behavior by quantitatively assessing the singular nature of the susceptibility of the system and the appearance of a pole for real values of frequencies. Hence, this methodology can be interpreted as a low-dimensional, reduced order approach to the investigation and detection of critical phenomena in high-dimensional interacting systems in settings where order parameters are not known.

The Electrical Behaviour of Railway Pantograph Arcs

Electric arcing is an unavoidable consequence of the current collection process by sliding contact in railways and metros, and in general in many electrified transportation systems (ETSs). The most relevant consequences in an electrical perspective are: the occurrence of transients triggering resonant behaviour and transient responses, reduction of the energy efficiency of the system, conducted and radiated disturbance, in particular for the new radio systems widely employed for signalling and communication. The involved parameters are many (type of materials, current intensity, DC and AC supply, relative speed, temperature), as well as the studied characteristics (arc instability and lifetime, dynamic behaviour, electrical system response, radiation efficiency and coupling to external radio systems). This work reports the state of the art in arc modelling, arcing experimental characterisation, interaction with the supply system, radiated emissions and disturbance to radio systems, providing a complete description of phenomena and of reference data, critically discussing similarity and differences between sources. Proposed arc models are many with different assumptions and simplifications for various applications, so that a critical review and discussion are a necessity, considering the many different approaches and not-so-obvious applicability. The comparison with experimental results highlights unavoidable discrepancies, also because of intrinsic arc variability and for the many involved parameters and operating conditions. The impact of the arc as embedded in the railway system is then considered, speaking of conducted and radiated phenomena, including interference to radio communication systems and arc detection. The most prominent effect for conducted emissions is the excitation of system resonances, including the LC filters onboard rolling stock and substations in DC railways, with consequences for disturbance and energy efficiency, and this is discussed in detail. Conversely, for high frequency emissions, the attenuation along the line circuit is significant and the effective distance of propagation is limited; nevertheless radiated electromagnetic field emissions are a relevant source of disturbance for radio systems within the ETS premises and outside (e.g., at airports). The published approaches to quantify performance reduction are discussed with emphasis on experimental methods.

Collective mode resonances in superfluid 3He–4He mixtures

The experimentally observed first and second sound resonances caused by vibrations of a closed quartz tuning fork in superfluid helium mixtures are studied. Taking into account the full set of hydrodynamic modes of the system allows us to explain the unusual behavior of second sound resonances observed in experiments due to the redistribution of energy between the dissipative mode and the second sound mode.

Dynamic analysis of boron nitride nanotube using different boundary conditions under influence of vacancy defect: Insights from finite element method

In this paper, the effect of defects such as atomic vacancies (single atom vacancies like boron atom(Vb) or nitrogen atom vacancy(Vn) and di-atomic vacancies(VB-N) corresponds to vacancy of one boron and adjacent one nitrogen atom) on the vibrational behaviour of a single-walled boron nitride nanotube (SWBNNT) are investigated using finite element modelling in context of their applicability as mass sensors. The change in resonance frequency produced by vacancy defects at various points throughout the span when a mass is connected to the tip has also been examined. Space frames with three-dimensional components and point masses have been used to explain the cantilevered armchair (5, 5) and zigzag (10, 0) SW-BNNT with changing vacancy defects. The position of atomic vacancy has been varied (i.e., at 25 %, 50 % and 90 % of length from fixed end) to investigate the effect of location of defect along the length on the resonance behaviour of SW-BNNT. Further defective BNNTs have been analysed in such a way that the same can be used as nanomechanical resonator for detecting small mass of the order of femtogram level. For this,a small mass (varying from 10-20 to 10−25kg) is attached at the tip of cantilevered SW-BNNT. Substantial drop in frequency shift is observed when the position of defect moves toward the free end. the excitation frequency of defective BNNT is larger near the free end as compared to pristine one.

Vanadium dioxide coatings with enhanced optical and thermochromic performances

Vanadium dioxide (VO2), a prospect intelligent heat-controlling materials, could be extensively applied in construction and automobiles as smart window coating for energy saving. However, the state-of-the-art VO2 coatings suffer from low solar modulation efficiency (ΔTsol) and unsatisfied transmittance in the visible region (Tvis), owing to the unreasonable particle size, small porosity as well as low-purity. In this line, herein, a simple, facile and cost-effective approach: i.e., annealing assisted solution strategy, was adopted to prepare VO2 coating with uniform particle size, high porosity and high-purity by using cetyltrimethylammonium bromide (CTAB) and home-made ammonium citrato-oxovanadate (IV) as dispersant and precursor, respectively. It is noticeable that the amount of CTAB is of vital importance for the particle size and porosity control, which in turn affects the overall performance of as-obtained VO2 coatings. The results demonstrate that the sample with small particle size and high porosity shows good local surface plasmon resonance behavior, high Tvis and enhanced ΔTsol. In correlation with simulation results, the sample prepared under molar ratio of CTAB to V is 0.1 displays superior ΔTsol of 13.4% and Tvis of 70.6%. Our work might provide a guidance for the modulation of the optical transmittance of VO2 nanoparticle coatings towards smart window coatings.

Characterization of Lab-on-Fiber-based dosimeters in ultra-high dose radiation fields

Next generation High Energy Physics (HEP) accelerators will require new devices and technologies capable of operating in extreme environments characterized by ultra-high radiation doses up to the MGy levels. To this aim, we report on an innovative Lab-On-Fiber (LOF) probe for the real-time dose monitoring. The proposed platform is based on a metallo-dielectric nanostructured grating made of gold and poly(methyl methacrylate) (PMMA) patterned on the termination of single mode fibers. The nanostructure has been judiciously designed to support a plasmonic resonance in the reflection spectrum occurring at near infrared wavelengths. Electron beam lithography was used for the fabrication of two LOF prototypes, which in turn, were exposed to X-rays with a total dose of 2.02 MGy and a dose rate of 88 kGy/h. Reflection spectra acquired during the irradiation revealed a clear dependence of the LOF resonance wavelength and depth on the absorbed dose, confirming the outcomes of our previous proton campaign. Morphological characterization of the irradiated samples showed that the main radiation induced effect is the reduction of the PMMA thickness (ranging between 26 % and 40 %), which in turn strongly affects the resonance behavior. Quantitative morphological measurements have been used to achieve a fair and objective correlation with our numerical modelling. Moreover, we investigated the effect of ultra-high doses of several radiation types, including X-rays, electrons and protons, on the thickness of PMMA nanolayers deposited on planar substrates. Experimental results revealed that the amount of absorbed dose (1.9–16.06 MGy) is the main parameter affecting the PMMA relative compaction (9.5–59.1 %), while the influence of the radiation type, dose rate and initial PMMA thickness can be considered negligible. Overall, these results pave the way to the development of radiation type independent PMMA assisted LOF dosimeters operating at MGy doses for the radiation monitoring in future HEP experiments.

Electromagnetically induced transparencies with two transverse Bose–Einstein condensates in a four-mirror cavity

We investigate electromagnetically induced transparencies with two transverse Bose–Einstein condensates in four-mirror optical cavity, driven by a strong pump laser and a weak probe laser. The cavity mode, after getting split from beam splitter, interacts with two independent Bose–Einstein condensates transversely trapped in the arms of the cavity along x-axis and y-axis. The interaction of intra-cavity optical mode excites momentum side modes in Bose–Einstein condensates, which then mimic as two atomic mirrors coupled through cavity field. We show that the probe field photons transition through the atomic mirrors yields to two coupled electromagnetically induced transparency windows, which only exist when both atomic states are coupled with the cavity. Further, the strength of these novel electromagnetically induced transparencies gets increased with an increase in atom-cavity coupling. Furthermore, we investigate the behavior of Fano resonances and dynamics of fast and slow light. We illustrate that the Fano line shapes and dynamics of slow light can be enhanced by strengthening the interaction between atomic states and cavity mode. Our findings not only contribute to the quantum nonlinear optics of complex systems but also provide a platform to test multidimensional atomic states in a single system.

Nonlinear planar and non-planar vibrations of viscoelastic fluid-conveying pipes with external and internal resonances

In this study, nonlinear vibrations of a viscoelastic fluid-conveying pipe under in-plane and out-of-plane transverse excitations are investigated, with emphasis on external and internal resonances. For this purpose, a three-dimensional pipe model that couples the in-plane and out-of-plane vibrations is developed based on the Euler–Bernoulli beam theory together with the Kelvin–Voigt viscoelasticity. The Galerkin method is performed on the nonlinear governing equations, and the resultant discretized equations are solved via the pseudo-arclength continuation method and a direct integration method. The dynamical responses of the pipe are examined in both sub- and super-critical regions and presented by plotting the frequency–amplitude curves, force–amplitude curves, basins of the attraction, time histories, and phase portraits. A comparison between the simplified two-dimensional model and the present three-dimensional model is presented to showcase the possibility of the in-plane and out-of-plane vibrations in regions of primary and principal parametric resonances, highlighting the modal interaction between the in-plane and out-of-plane transverse modes. In the presence of a two-to-one internal resonance, in addition to typical jumping and hysteresis, the two-peak resonance behavior is observed. The numerical results not only show complex nonlinear dynamics of the fluid–structure interaction system, but also provide hints for safe design and novel application of such structures.

Nonlinear coupled dynamics of suspended cables due to crossover points shifting and symmetry breaking

This work deals with the nonlinear coupled dynamics of suspended cables considering two unavoidable factors: temperature changes and damaged situations. Particularly, the thermal-induced crossover shifting and damage-induced symmetry-breaking are considered and investigated. A kinematically condensed mathematical model with thermal and damage effects simultaneously is employed for the transverse displacements. A weighted-residual technique based on the Galerkin method is adopted to reduce the continuous model from the partial differential equations to ordinary ones. Following the multiple scales procedure for a weakly nonlinear system, both the polar and Cartesian forms of modulation equations are achieved. Based on the eigenvalue analyses, natural frequencies and mode shapes with thermal and damage effects are presented, and the crossover and veering points between natural frequencies are observed. Resonant behaviors of suspended cables after crossover points shifting and symmetry-breaking are revealed by using the numerical continuation and bifurcation analysis. Quantitative and qualitative differences in dynamic behaviors induced by temperature and damage factors are exhibited and illustrated through some parametric studies. Direct numerical integration solutions are adopted to confirm the perturbation ones, and a good agreement is observed.

New magneto-polaron resonances in a monolayer of a transition metal dichalcogenide

Transition metal dichalcogenide (TMD) semiconductors are two-dimensional materials with great potential for the future of nano-optics and nano-optoelectronics as well as the rich and exciting development of basic research. The influence of an external magnetic field on a TMD monolayer raises a new question: to unveil the behavior of the magneto-polaron resonances (MPRs) associated with the phonon symmetry inherent in the system. It is shown that the renormalized Landau energy levels are modified by the interplay of the long-range Pekar–Fröhlich (PF) and short-range deformation potential (DP) interactions. This leads to a new series of MPRs involving the optical phonons at the center of the Brillouin zone. The coupling of the two Landau levels with the LO and A_1 optical phonon modes provokes resonant splittings of double avoided-crossing levels giving rise to three excitation branches. This effect appears as bigger energy gaps at the anticrossing points in the renormalized Landau levels. To explore the interplay between the MPRs, the electron-phonon interactions (PF and DP) and the couplings between adjacent Landau levels, a full Green’s function treatment for the evaluation of the energy and its life-time broadening is developed. A generalization of the two-level approach is performed for the description of the new MPR branches. The obtained results are a guideline for the magneto-optical experiments in TMDs, where three MPR peaks should be observable.

Development and evaluation of a titanium-based planar ultrasonic scalpel for precision surgery

This paper introduces a titanium-based planar ultrasonic microscalpel. The concept of silicon-based planar ultrasonic transducers has already been proven, but they are not yet suitable for clinical use due to material failure. The main objective of this work was to develop a smaller, lighter, and more cost-effective ultrasonic scalpel that could be used as an alternative or supplementary device to current surgical instruments. Various prototypes were fabricated and characterized, differing in bonding by three epoxy adhesives and two solder pastes as well as three variations in tip design. The instruments were designed to operate in the frequency range of commercial instruments and to generate a longitudinal displacement amplitude. The electro-mechanical characterization through impedance analysis and vibration measurements was complemented by an in vitro cutting trial and an acute in vivo animal experiment in comparison to commercial ultrasonic and electrosurgical devices. The operating frequency was around 40 kHz and 48 kHz depending on whether matched or unmatched operation was used. Unmatched operation turned out to be more suitable, achieving displacement amplitudes of 25.3 μm and associated velocity amplitudes of up to 7.9 m/s at an electrical power of 10.2 W. The cutting ability was demonstrated in vivo by successful dissection even under anticoagulation. The geometry of the instrument tip was found to have a major influence on cutting performance by affecting the resonance behaviour and tissue penetration.

Quantum interference between dark-excitons and zone-edged acoustic phonons in few-layer WS2

Fano resonance which describes a quantum interference between continuum and discrete states, provides a unique method for studying strongly interacting physics. Here, we report a Fano resonance between dark excitons and zone-edged acoustic phonons in few-layer WS2 by using the resonant Raman technique. The discrete phonons with large momentum at the M-point of the Brillouin zone and the continuum dark exciton states related to the optically forbidden transition at K and Q valleys are coupled by the exciton-phonon interactions. We observe rich Fano resonance behaviors across layers and modes defined by an asymmetry-parameter q: including constructive interference with two mirrored asymmetry Fano peaks (weak coupling, q > 1 and q < − 1), and destructive interference with Fano dip (strong coupling, ∣q∣ < < 1). Our results provide new insight into the exciton-phonon quantum interference in two-dimensional semiconductors, where such interferences play a key role in their transport, optical, and thermodynamic properties.

Model for vibrationally enhanced tunneling of proton transfer in hydrogen bond

Theoretical analysis of the effect of an external vibration on proton transfer (PT) in a hydrogen bond (HB) is carried out. It is based on the two-dimensional Schrödinger equation with trigonometric double-well potential. Its solution obtained within the framework of the standard adiabatic approximation is available. An analytic formula is derived that provides the calculation of PT rate with the help of elements implemented in Mathematica. We exemplify the general theory by calculating PT rate constant for the intermolecular HB in the Zundel ion H5O2+ (oxonium hydrate). This object enables one to explore a wide range of the HB lengths. Below some critical value of the frequency of the external vibration the calculated PT rate yields extremely rich resonant behavior (multiple manifestations of bell-shaped peaks). It takes place at symmetric coupling of the external vibration to the proton coordinate. This phenomenon is absent for anti-symmetric and squeezed mode couplings.

Triple-Band Square Split-Ring Resonator Metamaterial Absorber Design with High Effective Medium Ratio for 5G Sub-6 GHz Applications

This article proposes a square split-ring resonator (SSRR) metamaterial absorber (MMA) for sub-6 GHz application. The unit cell of the MMA was designed and fabricated on commercially available low-cost FR-4 substrate material with a dielectric constant o 4.3. The higher effective medium ratio (EMR) of the designed unit cell shows the compactness of the MMA. The dimension of the unit cell is 9.5 × 9.5 × 1.6 mm3, which consists of two split rings and two arms with outer SSRR. The proposed MMA operates at 2.5 GHz, 4.9 GHz, and 6 GHz frequency bands with a 90% absorption peak and shows a single negative metamaterial property. The E-field, H-field, and surface current are also explored in support of absorption analysis. Moreover, the equivalent circuit model of the proposed MMA is modelled and simulated to validate the resonance behavior of the MMA structure. Finally, the proposed MMA can be used for the specific frequency bands of 5G applications such as signal absorption, crowdsensing, SAR reduction, etc.

Reciprocal Ferromagnetic Resonant Behaviors Driven by Shear Strains in Isolated Skyrmions

Strain‐mediated magnetoelastic coupling provides a powerful way to manipulate the dynamics of magnetic textures because of its energy efficiency, which is promising for applications in spintronics. Herein, it is demonstrated that reciprocal ferromagnetic resonant behaviors can be induced in isolated skyrmions by applying inverse shear strains, physically originating from the symmetric deformations of skyrmions, which cannot exist in the ones induced by normal strains. A linear relationship between resonant frequencies (f) and shear strains (εxy) is given by f = ±24.4 × εxy + 0.03, where the symbols of + and − denote positive and negative shear strains, respectively. The resonant frequency increases from 0.1 to 0.98 GHz with the change of shear strains from −0.003 to −0.039 or from 0.003 to 0.039. The breathing mode is observed by profiles of temporal evolutions for dynamics of deformed skyrmions, ascribed to the applied microwave magnetic field along the out‐of‐plane direction. The proposed results can provide insight into controlling resonant frequencies by strain engineering.