Composite Resonator Research Articles

Mid‐life epigenetic age, neuroimaging brain age, and cognitive decline: Coronary Artery Risk Development in Young Adults (CARDIA) Study

AbstractBackgroundEstablishing biological aging markers that predict cognitive performance may aid early identification of individuals at risk for accelerated cognitive decline and promote the development of interventions to preserve optimal cognitive function across the lifespan. We investigated two distinct classes of biological aging markers, 1) epigenetic aging, an emerging class of blood‐derived DNA methylation markers that aggregate aging‐related DNA methylation information; and 2) Spatial Patterns of Abnormality for Recognition of Brain Aging (SPARE‐BA), a composite magnetic resonance imaging (MRI) index of brain aging.MethodWe evaluated the cross‐sectional and prospective associations between both classes of aging markers and cognitive performance across a 15‐year follow‐up in the biracial CARDIA cohort of approximately 1,000 middle‐aged adults, using multiple linear regression and logistic regression. We compared the diagnostic performance of both aging markers using receiver operating characteristic (ROC) curve analysis.ResultWe found that accelerated epigenetic aging and brain aging were both cross‐sectionally and prospectively associated with worse cognitive outcomes. Specifically, every 5‐year faster epigenetic/brain aging is on average associated with 9.7% standard deviation (SD) higher in Stroop Test score, 7.7% SD lower in Rey Auditory Verbal Learning Test score, and 10.3% SD lower in Digital Symbol Substitution Test (all false‐discovery‐rate‐adjusted p <0.05). ROC analysis showed that a combined model with both epigenetic aging and brain aging markers optimized discriminability of individuals with lower cognitive performance 5 to 10 years later (area under the ROC curve: 0.70; 95% confident interval: 0.63‐0.77, Figure). Epigenetic and brain aging markers were weakly correlated with one another (Person’s r =0.17) and not statistically significant.ConclusionOur results showcase the significance of novel biological aging markers for cognitive health. Accelerated epigenetic aging and brain aging may capture distinct facets of biological aging and may jointly serve as early indicators of future cognitive decline and inform early interventions to prevent or delay cognitive impairment.

Boron-nitride foam composite resonators

While boron-nitride foam (BNF) has shown remarkable properties, such as large surface area, wide bandgap, and high chemical and thermal stability, its realization as a resonator is a critical step toward its implementation into sensors, ultraviolet optical devices, and high-power systems. Here, we demonstrate BNF composite resonators. We first characterized the response of the resonators under mechanical loading, followed by their resonance excitation under the influence of Kelvin polarization force. In parallel, we built a model that clarifies the trends in the operation of our resonators. We found that the Kelvin polarization force induces a stiffening of the resonators, which allows resonance frequency tuning. Also, the Kelvin polarization force enables the excitation of BNF composites from a distance, while eliminating the need for high-precision fabrication and electrical wiring. Therefore, we uncover the fundamental physical behavior of BNF and pave the path toward its integration into advanced functional devices.

High-frequency magnetic response of superferromagnetic nanocomposites

Studies of the dynamical response of thin-film composites of magnetic nanoparticles embedded in dielectric matrices to the oscillatory magnetic field of the microwave-frequency range are performed using numerical simulations. Four soft-magnetic systems; (Co)0.42(MgF2)0.58, (Fe65Co35)0.57(SiO2)0.43, (Fe65Co35)0.75(Al2O3)0.25, (Fe65Co35)0.6(Al2O3)0.4, typical of a class of ”high-frequency ferromagnetic nanocomposites” are simulated. The necessary micromagnetic parameters are extracted from data within the model of random magnetic anisotropy (RMA). Those materials are candidates for use in micro-converters of power (inductors and transformers) due to their high saturation magnetization, high resistivity, and absence of intra-grain magnetic domains. Thus, they are able to create a high magnetic flux at low power losses. The simulations allow for an inspection into details of the spatial distribution of the oscillating magnetization. We predict noticeable differences in the ferromagnetic resonance (FMR) in different composites which are related to the shape of the static hysteresis. Operating ranges of the driving-field amplitude are related to the hysteresis width. Next to FMR, we analyze the magnetic response via the oscillatory motion of domain walls in a longitudinal field. Besides the response to the alternating field of a constant direction, we study the magnetization dynamics driven by in-the-plane-rotating field. Such a field can drive the magnetization rotations which are a strong-response (nonlinear) mode potentially useful for efficient power conversion.

Noise generation in a bilayer ferromagnet-piezoelectric heterostructure at the converse magnetoelectric effect

The paper describes first observation of parametric generation of noise in a composite multiferroic resonator. Resonator of a disk shape contains two mechanically coupled layers, one of which is the amorphous ferromagnet (FM) FeBSiC and the other is the piezoelectric (PE) lead zirconate titanate. DC magnetic field of 0–100 Oe is applied parallel to the plane of the resonator. Resonator is excited in the frequency range f = 2–10 kHz by a harmonic electric field with amplitude of up to 330 V cm−1 applied to the PE layer. Changes in the magnetization of the resonator caused by the converse magnetoelectric effect were recorded using an electromagnetic coil. With an increase in the excitation field to the threshold value, the parametric generation of harmonics and subharmonics with a discrete spectrum is observed, which then turns into a stochastic mode and a continuous spectrum of frequencies is generated. Noise density is hysterically dependent on the excitation field and non-monotonically depends on the dc magnetic field. Theory of parametric generation of the noise in a multiferroic resonator is developed, taking into account excitation of acoustic resonances and magnetoacoustic nonlinearity of the FM layer of the resonator. Theory, qualitatively describes the main characteristics of noise generation.

Whispering gallery mode resonance excitations on a partially gold coated bottle microresonator

The study on the excitations of whispering gallery mode (WGM) resonances optical bottle microresonator (BMR) partially coated with a thin gold Au metal film is presented. The BMR was fabricated through “soften-and-compress” technique on a small section of standard optical fibre. Depositing Au particles on the spheroidal curvature of the BMR surface yields a thin metal-film of a meniscus profile with 200 nm maximum gold thickness and tapered edges. A polarization resolved experimental setup was used to excite TE- and TM-mode resonances. Coupling strengths of the excited WGMs would vary with different coupling arrangements relative to the position of the meniscus Au film. Calculated Q-factor values of composite TE and TM mode resonances were determined to be in the range 1800 and 2700, respectively.

A novel hybrid composite phononic crystal plate with multiple vibration band gaps at low frequencies

The low-frequency vibration isolation of a new hybrid phononic crystal plate are numerically and experimentally demonstrated in this paper. The proposed structure is composed of two types of periodic double-sided composite resonators deposited on a two-component plate. The dispersion relations, transmission spectra, and displacement fields of the eigenmodes are calculated by the finite element method. Compared to the classical phononic plate, the proposed structure can generate multiple flexural and longitudinal band gaps (BGs) at low frequencies. The formation mechanisms of the BGs can be explained by the corresponding “analogous-rigid modes”. The results of the parametric analyses show that the BGs can be significantly modulated by adjusting the material and geometric parameters. Furthermore, shake tests on a fabricated specimen were performed to verify the attenuation performance for elastic waves of specific frequency ranges. This research indicates that the proposed structure is a promising option for broadband low-frequency vibration insulation.

1.5 μm Eye-safe self-optical parametric oscillator with composite resonator based on Nd3+-doped MgO:PPLN

The self-optical parametric oscillator with composite resonator based on Nd3+-doped MgO:PPLN is reported in this paper, which can achieve 1.5 μm eye-safe laser. Under different thermal focal length of Nd:MgO:PPLN, the focusing parameter ratio of 1084 nm to 1512 nm, and 1084 nm spot radius are simulated, which settle the best parameters of the resonator. By 813 nm double-end pumping, a laser pulse of 15.3 μJ at 1512 nm is realized with 60 kHz Q-switched repetition rate. The conversion efficiency of 1084 nm to 1512 nm is 33.7%, the peak power is 1.26 kW, and the power fluctuation is 3.1% respectively.

2.1 μm self frequency conversion optical parameter oscillator based on Nd3+ doped MgO:PPLN

A 2.1 μm integrated self frequency conversion optical parametric oscillator which based on Nd3+ doped MgO:PPLN with intra-cavity acousto-optic Q-switched is reported. Under different thermal focal lengths of Nd3+ doped MgO:PPLN, the focusing parameter ratio of 1084 nm and 2168 nm and the spot radius of 1084 nm are simulated, and the optimal parameters of the composite resonant cavity are determined. According to the quasi-phase matching principle, 1093 nm is effectively suppressed by the design of the composite resonator, and a single-wavelength output of 1084 nm is obtained. The 2.1 μm self frequency conversion optical parametric oscillator with Nd3+ doped MgO:PPLN is realized for the first time, the output power is 1.21 W, the highest down-conversion efficiency from 1084 nm to 2.1 μm is 15.1%. The pulse width of 2168 nm is around 7.8 ns when the repetition rate is 40 kHz.

Electromagnetic characterization of tuneable graphene‐strips‐on‐substrate metasurface over entire THz range: Analytical regularization and natural‐mode resonance interplay

Scattering and absorption of the H-polarized plane wave by the infinite grating of flat graphene strips are considered in the environment met most frequently—on or at the surface of a dielectric-slab substrate. The full-wave meshless code is based on the analytical semi-inversion using the Riemann–Hilbert problem solution. This leads to a Fredholm second-kind matrix equation for the Floquet harmonic amplitudes that guarantees code convergence and provides easy control of computational error, which can be reduced to machine precision. The matrix elements are combinations of elementary functions, and therefore, the code is accurate and quite economical. This enables computation of the reflectance, transmittance, and absorbance as a function of the frequency in the wide band from static case to 10 THz. Numerical results show that such a metasurface with micrometre-sized strips is a composite periodic open resonator. It is highly frequency-selective thanks to the interplay of three types of natural modes—low-Q slab, moderate-Q plasmon strip, and ultra-high-Q lattice—that do not exist in the absence of the substrate. Varying the chemical potential of graphene, one can manipulate the electromagnetic characteristics of the metasurface at a fixed frequency from almost total transmission to almost total reflection.

Multiple cooperative amplification paper SERS aptasensor based on AuNPs/3D succulent-like silver for okadaic acid quantization

Okadaic acid (OA) is the main toxic component of diarrhetic shellfish poisoning, which can cause vomiting, diarrhea, and even induce tumor formation in people who accidentally ingest it. To strengthen the front-end prevention and control of shellfish safety, a surface-enhanced Raman scattering (SERS) paper swab based on high-affinity binding and high-specific recognition performance of nucleic acid aptamer was proposed to detect OA by virtue of enhanced multistage plasmon coupling effect. Composite resonance bilayer constituted by evenly dispersed gold nanoparticles integrating with a three-dimensional (3D) succulent-like silver particle was facilely manufactured in-situ on the paper substrate. Subsequently, with the assistance of 3D nanotopography structured silver nano-octahedra connected on the signal probe, a multistage SERS signal cooperative amplification platform was formed with about 10-fold enhanced Raman intensity higher than either single-layer substrate. Owning to the unique strategy of superimposed signal enhancement, such paper SERS aptasensor possessed admirable specific recognition and sensitivity has been successfully used in the on-site quantization of OA, with a detection limit of 0.31 ng/mL. Furthermore, the construction of the SERS paper swab is of great significance to the promotion of rapid on-site analysis approach of OA content in seafood by customs, seafood market supervision departments and ordinary consumers.

DEPENDENCE OF PHYSICAL PROPERTIES OF PIEZOELECTRIC ALUMINUM-SCANDIUM NITRIDE ON SCANDIUM CONCENTRATION

In this work the physical properties of the piezoelectric aluminum-scandium nitride (ASN) solid solution as a function of scandium concentration were studied using the density functional theory and experimental methods. The phase transition from the wurtzite phase to the rock salt phase at a Sc concentration of 43% was shown. The barriers of transformation from the wurtzite phase to the rock salt phase for various Sc concentrations were obtained. The behavior of the ASN piezoelectric constant d33 calculated by the piezoelectric constants e33, e31, and e15 shows a sharp increase with increasing Sc concentration compared to aluminum nitride AlN. The relationship between the increase in the piezoelectric response of ASN and the softening of the lattice, accompanied by a decrease in the main elastic constants C11, C33, C44 and C66, as well as a decrease in the c/a ratio with increasing Sc concentration, is shown. ASN films with a predominance of the crystal orientation (00·2) were obtained experimentally by magnetron sputtering. The structural properties of the films were studied by X-ray diffraction analysis. A comparison of the experimentally obtained dependence of the c/a ratio on the Sc concentration with the theoretical values showed a good correspondence. Studies of the physical properties of ASN thin films were performed using microwave multi-overtone composite resonators on diamond substrates with a longitudinal bulk acoustic wave (BAW) as the operating mode in the range of 0.5 – 20 GHz. The frequency dependences of the Q-factor of BAW-resonators with different ASN films were obtained, and the frequency dependences of the square of the modulus of the form factor as |m|2 were calculated. The dependences of the elastic constant С33 and the piezoelectric constant e33 for the ASN films with different Sc concentrations were calculated. The calculated and measured values of these constants are agreed within the experimental error.

Ultrawide FSR microring racetrack resonator with an integrated Fabry–Perot cavity for refractive index sensing

We propose a simple route to obtain an ultrawide free spectral range (FSR) using a composite racetrack microring resonator (RMRR) with Fabry–Perot cavities. The presence of two Fabry–Perot cavities in the straight arm of the RMRR suppresses other peaks while yielding a single resonance dip with a high extinction ratio. A comprehensive, detailed mathematical description and finite difference time domain (FDTD) simulations investigate the proposed device performances. The modified RMRR yields an FSR value greater than 150 nm while retaining the unmodified ring resonator’s Q -factor. Other than its application in communications, the device also will be highly useful for sensing. FDTD simulations show a sensitivity of 185 nm/RIU, which is 2.6 times larger than the unmodified RMRR. The proposed device also enjoys compactness and a wide tunability range and has less fabrication complexity. The proposed sensor could be a strong candidate in optical communications, optical switching, and many other applications.

A compact hybrid dielectric resonator antenna for multiband in wireless applications

This article exhibits the composite dielectric resonator antenna (DRA) for ISM band, Wi-Max and WLAN applications. The proposed DRA is aiming for speech signal and video transmission in the range of wi-max/WLAN. DRA’s are used in many digital signal processing applications because they are capable of locating signal sources. Microstrip feed line excites the exhibited structure. A circular dielectric resonator antenna with circular ring and cross shaped strip is designed to generate tri-band characteristics. The proposed antenna structure cover three different frequency bands, i.e. 1.85–2.5 GHz, 2.97–3.92 GHz and 4.821–5.9 GHz, with the fractional bandwidth of 30.1%, 27.5% and 20.9% respectively. An ISM band, Wi-max as well as WLAN are being utilized for correspondence of continuous traffic including speech signal, video and information to supervise medical issues in wireless body area networks (WBAN) advancement. To strengthen the resonator appearance as well as miniaturize the volume, the customized circular metallic component and cross shaped strip are stacked onto the substrate. The simulated results are verified by using fabricated antenna and the results are compared. The proposed model is strongly encouraging the wireless applications.

Use of the Composite Properties of a Microwave Resonator to Enhance the Sensitivity of a Honey Moisture Sensor.

A moisture sensor based on a composite resonator is used to measure different honey samples, which include imitation honey. The sensor changes its frequency response in accordance with the dielectric permittivity that it detects in the measured samples. Although reflectometry sensors have been used to measure the percentage of moisture in honey for almost a century, counterfeiters have achieved that their apocryphal product is capable of deceiving these kinds of sensors. Metamaterial features of the composite resonators are expected to improve their response when detecting lossy samples such as organic samples. It is also sought that these sensors manage to detect small differences not only in the real parts of the dielectric permitivities of samples but also in their imaginary parts, and, thus, the sensors are able to discern between real honey and slightly altered honey. Effectively, not only was it possible to improve the response of the sensors by using lossy samples but it was also possible to identify counterfeit honey.

CarDiac magnEtic Resonance for prophylactic Implantable-cardioVerter defibrillAtor ThErapy in Non-Ischaemic dilated CardioMyopathy: an international Registry

The aim of this registry was to evaluate the additional prognostic value of a composite cardiac magnetic resonance (CMR)-based risk score over standard-of-care (SOC) evaluation in a large cohort of consecutive unselected non-ischaemic cardiomyopathy (NICM) patients. In the DERIVATE registry (www.clinicaltrials.gov/registration: RCT#NCT03352648), 1000 (derivation cohort) and 508 (validation cohort) NICM patients with chronic heart failure (HF) and left ventricular ejection fraction <50% were included. All-cause mortality and major adverse arrhythmic cardiac events (MAACE) were the primary and secondary endpoints, respectively. During a median follow-up of 959 days, all-cause mortality and MAACE occurred in 72 (7%) and 93 (9%) patients, respectively. Age and >3 segments with midwall fibrosis on late gadolinium enhancement (LGE) were the only independent predictors of all-cause mortality (HR: 1.036, 95% CI: 1.0117-1.056, P < 0.001 and HR: 2.077, 95% CI: 1.211-3.562, P = 0.008, respectively). For MAACE, the independent predictors were male gender, left ventricular end-diastolic volume index by CMR (CMR-LVEDVi), and >3 segments with midwall fibrosis on LGE (HR: 2.131, 95% CI: 1.231-3.690, P = 0.007; HR: 3.161, 95% CI: 1.750-5.709, P < 0.001; and HR: 1.693, 95% CI: 1.084-2.644, P = 0.021, respectively). A composite clinical and CMR-based risk score provided a net reclassification improvement of 63.7% (P < 0.001) for MAACE occurrence when added to the model based on SOC evaluation. These findings were confirmed in the validation cohort. In a large multicentre, multivendor cohort registry reflecting daily clinical practice in NICM work-up, a composite clinical and CMR-based risk score provides incremental prognostic value beyond SOC evaluation, which may have impact on the indication of implantable cardioverter-defibrillator implantation.

High-Overtone Thin Film Ferroelectric AlScN-on-Silicon Composite Resonators

This letter presents the first demonstration of thin-film ferroelectric Aluminum Scandium Nitride (AlScN)-on-silicon composite resonators, targeting high-overtone resonance modes in the sub-6GHz band with a high figure of merit (FoM). The resonators are based on sputtered ferroelectric AlScN films with Sc/(Al+Sc) ratio of ~30% and thickness of $\sim 1 {\mu }\text{m}$ . Two types of AlScN thickness-extensional (TE) resonators are co-fabricated on the same SOI platform; with and without a $3.55~\mu \text{m}$ -thick Si layer in the resonant stack. We show that although the passive Si device layer underneath the thin piezo-stack results in degradation of the electromechanical coupling coefficient $({k}_{t}^{2})$ , it boosts the quality factor $({Q})$ , provides structural robustness, and improves the overall ${Q} \times {k}_{t}^{2}$ FoM. The resonant frequency spectrum of the high-overtone TE modes of AlScN-on-Si composite resonator is analyzed and the dependency of ${k}_{t}^{2}$ on the Si device layer properties is studied. A high ${k}_{t}^{2}$ value of 11.7% at the 3rd-order TE resonant frequency of 2.4 GHz is reported, yielding a high ${k}_{t}^{2}\times {Q}_{\textit {max}}$ FoM of 84. The reported FoM shows $2\,\, {\times }$ improvement compared to the co-fabricated AlScN-only FBARs.

Glucose detection by gold modified carboxyl-functionalized graphene quantum dots-based surface plasmon resonance

In this work, a graphene quantum dots composite thin film-based surface plasmon resonance (SPR) sensor was developed and experimentally demonstrated for glucose detection. The proposed work incorporates the modification of SPR gold film with carboxyl-functionalized graphene quantum dots-nanocrystalline cellulose (CGQDs-NCC) to improve the detection sensitivity of glucose. The sensing performances of gold/CGQDs-NCC thin film as a function of the sensitivity and binding affinity were analysed. The experimental results show that the linear response of the gold/CGQDs-NCC thin film were 13.296° μM−1, 0.13983° μM−1 and 0.00753° μM−1 for the 0 μM to 0.03 μM, 0.03 μM to 0.5 μM and 0.5 μM–10 μM of glucose concentrations, respectively. The binding affinity has been analyzed using Langmuir and Sips model where it revealed that gold/CGQDs-NCC thin film has higher affinity constant as compared to unmodified gold film. All in all, this paper gives the idea that the introduction of gold-modified CGQDs-NCC thin film in SPR has good potential for detecting glucose solution.

A High-Order Load Model and the Control Algorithm for an Aerospace Electro-Hydraulic Actuator

It is difficult to describe precisely, and thus control satisfactorily, the dynamics of an electro-hydraulic actuator to drive a high thrust liquid launcher engine, whose structural resonant frequency is usually low due to its heavy inertia and complicated mass distribution, let alone one to drive a heavy kerolox engine with high-order dynamics. By transforming classic control block diagrams, a baseline two-mass-two-spring load model and a normalized actuator-engine system model were developed for understanding the basic physics and methodology, where a fourth-order transfer function is used to model the multi-resonance-frequency engine body outside of the rod position loop, another fourth-order transfer function with two pairs of conjugated zeros and poles to represent the composite hydro-mechanical resonance effect in the closed rod position loop. A sixth-order model was thereafter proposed for even higher dynamics. The model parameters were identified and optimized by a full factor search approach. To meet the stringent specification of static and dynamic performances, it was demonstrated that a notch filter network combined with other controllers is needed since the traditional dynamic pressure feedback (DPF) is difficult to handle the high-order dynamics. The approach has been validated by simulation, experiments and successful flights. The models, analysis, data and insights were elaborated.

Single-Frequency Amplitude-Modulation Sensor for Dielectric Characterization of Solids and Microfluidics

A microfluidic sensor based on a microstrip line loaded with a composite resonator is reported in this paper. The composite resonator combines a shunt connected step impedance resonator (SIR) and a complementary split ring resonator CSRR) etched in the ground plane. By etching the CSRR beneath the patch of the SIR, the composite CSRR-loaded SIR resonator exhibits two transmission zeros and a pole in between. The operating principle of the sensor is the variation of the transmission coefficient at the pole frequency of the bare resonator, when a material or liquid under test (LUT) is in contact with the CSRR (the sensitive element). By designing the CSRR-loaded SIR resonator with closely spaced pole and transmission zeros, highly sensitive sensors are obtained. Despite the fact that the proposed sensor can also operate as a frequency variation sensor, using it as a single-frequency sensor based on the variation of the transmission coefficient (caused by the LUT) at a specific frequency reduces sensor costs. The reason is that a harmonic signal injected to the input port of the microstrip-based sensor plus a simple amplitude modulation (AM) detector (connected to the output port) suffices for measuring purposes. The proposed microfluidic sensor is applied to the characterization of volume fraction of solutions of isopropanol in deionized (DI) water. The sensor is able to resolve volume fractions as small as 5%, and the maximum measured sensitivity is as good as 4 mV/%.

Athermal high-Q tantalum-pentoxide-based microresonators on silicon substrates

Integrated microresonators with low thermal drift of resonant wavelength are imperative photonic devices to provide stable multiplexing/filtering functions on silicon substrates with large thermo-optic coefficient. To realize athermal microresonators with high quality factor and small footprint, we present an undercut Ta2O5-based microdisk resonator on the Si substrate using a facile lift-off process on the sputtered film and chemical etching. Dependences of surface morphology, crystalline property, refractive index and extinction coefficient of Ta2O5 film on the annealing temperature are studied to reveal favorable parameters for the microresonator production. The produced 40 μm-diameter Ta2O5 microdisk resonator exhibits low thermal drift (7.40 pm/°C), high quality factor (1.65 × 104) and wide free spectral range (11.5 nm). The measured thermo-optic coefficient at the wavelength 1550 nm is 3.0 × 10−6/°C. The thermal stability is further enhanced by using the TiO2 film with the negative thermo-optic coefficient. The study of Ta2O5/TiO2 composite microdisk resonators achieves high thermal stability as best as 0.26 pm/°C.