Antiresonance Research Articles

Predicting the dental implant stability based on the antiresonance phase of a piezo-based impedance sensor

Background: The stability of dental implants (DIs) in in vivo tests can be determined using noninvasive resonance frequency analysis technique. A low-cost piezo-based sensor has been developed for this purpose which uses a readily available two-terminal piezo element, to which a metal substrate is adhesively glued for attaching the implant. Aim: The attainment of implant stability in dynamic tests using this sensor must be standardized in terms of the major antiresonance (AR) in the impedance phase responses using sensor-DI assembly. This will be used to predetermine the dimensions of the glued metal substrate in the sensor design. Materials and Methods: Multiple sensors with varying sensor dimensions were developed. Static and dynamic impedance studies were performed on these and corresponding sensor-implant assemblies. Static tests as well as in vitro tests with the sensor-implant assembly dipped in a standardized dental plaster mixture were performed in controlled laboratory conditions. Results: The probability of acceptance of the hypothesis has been checked using binomial distribution with a significance level of 5%. Statistically observed that for 95% of the cases where the DI becomes stable in dental plaster, both AR phase and AR frequency (ARF) return to their corresponding static values. Furthermore, for a piezo element, whose ARF is within 6–6.6 kHz, the sensor yields maximal phase when the length of the metallic strip is 2 cm. Conclusions: Experimental validation supports both claims. Hence, this work can be extended to in vivo DI stability determination and design aspects of the corresponding sensor.

Impact of contact couplings on thermoelectric properties of anti, Fano, and Breit-Wigner resonant junctions

Quantum interference is a well-known phenomenon which results in unique features of the transmission spectra of molecular junctions at the nanoscale. We investigate and compare the thermoelectric properties of three types of junctions like the anti, Breit-Wigner, and Fano resonances. Due to its asymmetric line-shaped transmission function, Fano resonances lead to a larger thermoelectric figure of merit (ZT) than the symmetric anti and Breit-Wigner resonances. The occurrence of quantum interference in molecular and other nanoscale junctions is independent of contact couplings between the sandwiched molecules and left/right electrodes. However, it is found that the contact couplings determine the electric and thermoelectric performances of quantum interference junctions. In anti-resonant junctions, the Seebeck coefficient is enhanced by strong contact couplings. By contrast, for Breit-Wigner resonant junctions, this same property will increase in the weak contact coupling regime. Contrary to what is observed for anti and Breit-Wigner resonant junctions, some optimal contact couplings are found in Fano-resonant junctions for which the maximum Seebeck coefficient and ZT are obtained. Finally, thermoelectric properties are also investigated when the resonances crossover from Breit-Wigner to Fano types and, subsequently, to anti resonances.

Novel mass detection based on magnetic excitation in anti-resonance region

A novel mass sensor resonator in anti-resonance mode to detect the particles in the order of picogram is proposed. The model is a cantilever beam composed of a PZT-5A layer as readout and Metglas 2605SC as a magnetostrictive material. The cantilever beam is exposed to harmonic magnetic field; once the Metglas experiences the magnetic field, undergoes mechanical strain and as a result the PZT-5A gives off electrical potential difference throughout the output circuit. The governing motion equations in the presence of the added distributed mass is derived and numerically integrated over the time. The voltage frequency response curves are determined. The results reveal that for small enough external loads in the output circuit between two successive natural frequencies, there exist an anti resonance region where the steady state response amplitude dramatically drops. Once the added mass is deposited on the micro beam the frequency response curve is shifted along the frequency domain and as a result the response amplitude suddenly jumps which is used as a measure of the added mass.

反共振を含む制御対象におけるSACの問題点とPFCの設計による改善

反共振を含む制御対象におけるSACの問題点とPFCの設計による改善

Zero-conductance resonances and spin polarizations in three-terminal rings in the presence of spin-orbit coupling

Spin dependent transport in one-dimensional (1D) three-terminal rings is investigated in the presence of the Rashba spin-orbit coupling (RSOC). We focus on zero-conductance resonances and spin polarizations. For these purposes, the transmission functions are derived analytically. The total conductances are analyzed in the complex energy plane with a focus on the zero-pole structure characteristic of transmission (anti)resonances. The spin polarizations in symmetrically and asymmetrically coupled three-terminal rings are studied as a function of the incident electron energy. It is found that in the absence of the RSOC there are three kinds of conductance zeros. In the presence of the RSOC, the zeros of the first and the third kinds are lifted, while some of the second kind persist. The lifting of the conductance zeros is related to the breaking of the spin-reversal symmetry, and the lifted conductance zeros evolve into spin polarization zeros.

Conductance in quantum wires by three quantum dots arrays

A noninteracting quantum-dot arrays side coupled to a quantum wire is studied. Transport through the quantum wire is investigated by using a noninteracting Anderson tunneling Hamiltonian. The conductance at zero temperature develops an oscillating band with resonances and antiresonances due to constructive and destructive interference in the ballistic channel, respectively. Moreover, we have found the number of antiresonant exactly depends on the number of quantum dot in every array and increasing array make antiresonants wide increase.

Zero-conductance resonances and spin filtering effects in ring conductors subject to Rashba coupling

We investigate the effect of Rashba spin-orbit coupling and of a tunnel barrier on the zero conduc- tance resonances appearing in a one-dimensional conducting Aharonov-Bohm (AB) ring symmet- rically coupled to two leads. The transmission function of the corresponding one-electron problem is derived within the scattering matrix approach and analyzed in the complex energy plane with focus on the role of the tunnel barrier strength on the zero-pole structure characteristic of trans- mission (anti)resonances. The lifting of the real conductance zeros is related to the breaking of the spin-reversal symmetry and time-reversal symmetry of Aharonov-Casher (AC)and AB rings, as well as to rotational symmetry breaking in presence of a tunnel barrier. We show that the polarization direction of transmitted electrons can be controlled via the tunnel barrier strength and discuss a novel spin-filtering design in one-dimensional rings with tunable spin-orbit interaction.

Design Method of Sound Absorber for Anti Acoustic Resonance in Tube Bundles Based on Acoustic FEM

Equipment of sound absorbers mid-air in the duct is an effective countermeasure for anti acoustic resonance in tube bundles of heat exchangers. Its design method, including the number or placement of absorbers in the duct space for efficient performance, was developed based on acoustic FEM. Here, the acoustic characteristics of absorbers, such as effective bulk modulus, loss factor or density of the air within the absorbers are needed. These parameters are evaluated by flow resistance method or impedance tube method. Complex eigenvalue analysis with acoustic FEM is executed which yields the increase of modal damping ratio by the equipment of absorbers. In order to verify the above-mentioned method, the acoustic experiment with the scale model of coal-fired boilers was conducted and experimental and analytical results are in good agreement. Finally this method was applied to the actual boiler plant and based on these results, it was confirmed that the proposed method is the effective countermeasure for the and acoustic resonance in heat exchangers.

Effect of spin-orbit coupling on zero-conductance resonances in asymmetrically coupled one-dimensional rings

The influence of Rashba spin-orbit coupling on zero conductance resonances appearing in one dimensional ring asymmetrically coupled to two leads is investigated. For this purpose, the transmission function of the corresponding one-electron scattering problem is derived analytically and analyzed in the complex energy plane with focus on the zero-pole structure characteristic of transmission (anti)resonances. The lifting of real conductance zeros due to spin-orbit coupling in the asymmetric Aharonov-Casher (AC) ring is related to the breaking of spin reversal symmetry in analogy to the time-reversal symmetry breaking in the asymmetric Aharonov-Bohm (AB) ring.

Study of piezoelectric, magnetic and magnetoelectric measurements on SrBi 3Nb 2FeO 12 ceramic

SrBi 3Nb 2FeO 12 (SBNF) is a three-layered perovksite in the system SrBi 2Nb 2O 9 (SBN) + ( n). BiFeO 3 (BF) system with n=1. In order to achieve the magnetic and magnetoelectric (ME) nature, the material should consist of ferroelectric and magnetic ordering. In the present system, the addition of BiFeO 3 to SBN makes the material both ferroelectric and magnetic, to realise magnetoelectric output. The piezoelectric nature of the material is investigated by using the resonance and anti resonance measurement. The magnetisation measurements carried out at room temperature showed a slim hysteresis loop indicating the material consists of antiferromagnetic ordering. The dynamic magnetoelectric measurements performed at room temperature and at 77 K, showed that magnetoelectric output is high at 77 K.

Delocalized polarons in self-assembled poly(3-hexyl thiophene) nanocrystals

We have studied the characteristic properties of charged excitations (polarons) in thin films of regioregular poly(3-hexylthiophene) (RRPHT) by optical spectroscopies. We found that the increased interchain coupling that exists in self-assembled lamellae in these films drastically changes the properties of the polaron excitations. The traditional self-localized polaron in one-dimension delocalizes in two-dimensions, resulting in a much-reduced relaxation energy and multiple absorption bands, the most dominant being in the mid-infrared (IR) spectral range. Also it has associated IR and Raman active vibrations with reverse absorption bands [anti-resonances (AR)] compared with the continuum electronic band. The AR are attributed to the electron–phonon interaction.

Fano antiresonances of Cr 3+ in alkaline disilicate glasses

This work is devoted to a study of the features of the long-wavelength 4A 2→ 4T 2 absorption band of Cr 3+ ions in alkaline disilicate glasses. These features result from interaction of the 2E and 2T 1 sharp levels with the vibrationally broadened 4T 2 quasicontinuum via spin-orbit coupling and have been analysed in the frame of the Fano antiresonances model. The anti resonance profiles have been obtained from the ratio of the observed absorption spectra to the background spectra, the latter consisting of a single- or double-Gaussian function. The four fitted parameters involved in this model give information about the fraction of the quasicontinuum which takes part in the interference processes, the lineshape profile of the antiresonance, the width of the sharp level and its shift due to interaction with the quasicontinuum. These parameters have been calculated for Li, Na, and K disilicate glasses in the temperature range from 12 to 300 K.

Effects of a Series Capacitor on the Energy Consumption in Piezoelectric Transducers at High Vibration Amplitude Level

In this paper, a driving method for low-loss generation in piezoelectric transducers at a high vibration amplitude level is presented. First, we analyze the power consumption of several loss mechanisms of piezoelectric transducers using an electrical equivalent circuit model. In this model, loss due to piezoelectric effect is explicitly represented by a series resistor, and pure dielectric loss is separately denoted by a parallel resistor. Mechanical loss is represented by a series resistor in the mechanical arm. The reason for the high efficiency at the anti resonance frequency is explained by this analysis. Next, the effect of an external series capacitor is discussed by comparing the experiment with the calculation, based on the equivalent circuit model for the high vibration amplitude level. By using the external series capacitor, the loss generated at the high vibration amplitude was significantly reduced without a large increase in electrical impedance.

How does a cone mimic a doubly closed pipe?

An idealized conical bore that is complete to its apex has been used as the basic model for several wind instruments with tone holes, such as oboe, bassoon, saxophone, and cornetto. The useful playing frequencies for these relatively short instruments include those near the first peak in |Z|. A uniform pipe that is closed at both ends has been proposed as the basic bore shape for the brasses, including even their strongly conical representatives, such as tube and cavalry bugle [R. D. Ayers, J. Acoust. Soc. Am. 98, 81–87 (1995)]. The relationship should be considered one of mimicry, since there are major discrepancies at low frequencies, and these extend to the first (anti)resonance or higher. The nature of that relationship and the way in which it is achieved are perhaps most easily understood by examining a conical frustum, with or without a lumped-element mouthpiece, from this new perspective. Fairly simple behaviors in the time domain provide the explanation for the mimicry in the frequency domain.

The origin of anti‐resonance in preresonance Raman scattering

The origin of anti‐resonance in preresonance Raman scattering

The origin of anti-resonance in preresonance Raman scattering

The origin of anti-resonance in preresonance Raman scattering

Traces of a quantum antiresonance in a driven system.

It has been previously shown, that classically chaotic kicked systems, whose unperturbed spectrum posseses one energy scale, admits a quantum anti-resonance (QAR) behavior. In this study we extend the conditions under which which this QAR occurs for the case of a two-sided kicked 1D infinite potential well. It is then shown by a perturbative argument that this QAR effects the behavior of the equivalent driven well, i.e., the number of periods needed to leave the initial state has a sharp peak around the QAR. We give a numerical evidence that the anti resonance persists even for large values of the perturbation parameter.

The Aharonov-Casher theorem and the axial anomaly in the Aharonov-Bohm potential

The spectral properties of the Dirac Hamiltonian in the the Aharonov-Bohm potential are discussed. By using the Krein-Friedel formula, the density of states (DOS) for different self-adjoint extensions is calculated. As in the nonrelativistic case, whenever a bound state is present in the spectrum it is always accompanied by a (anti) resonance at the energy. The Aharonov-Casher theorem must be corrected for singular field configurations. There are no zero (threshold) modes in the Aharonov-Bohm potential. For our choice of the 2D Dirac Hamiltonian, the phase-shift flip is shown to occur at only positive energies. This flip gives rise to a surplus of the DOS at the lower threshold coming entirely from the continuous part of the spectrum. The results are applied to several physical quantities: the total energy, induced fermion-number, and the axial anomaly.

Parameter Identification Method for Two Inertia Resonant Systems by Use of Both Observer and FFT.

In this paper, we propose a new parameter identification method for two inertia resonant systems with unknown Coulomb friction. The proposed method consists of two parts : the rigid model identification of the low-frequency band and the vibration model identification of the high frequency band. In the rigid model identification, we use the disturbance observer to identify the rigid model parameters. On the other hand, in the vibration model identification, fast Fourier transform is used to obtain the gains at the mechanical resonance frequency and at the anti resonance frequency. The gain curve fitting method based on both the rigid model parameters and the vdbration model parameters enables the elimination of the gain distortion caused by Coulomb friction and the estimation of the exact parameters.

Total respiratory input impedance with the upper airway wall shunt minimized

Respiratory impedances (Zrs) measured with the cheeks manually supported (Zsc) demonstrate an antiresonance (AR) at approximately 170 Hz, whereas those measured with the head generator (Zhg) have an AR at significantly lower frequencies (150 Hz). The differences in the AR between methods were previously attributed to upper airway wall (UAW) shunting in Zsc, and Zhg was believed to represent shunt-free impedance. To test this hypothesis, we measured four independent estimates of Zrs (4-256 Hz) in five healthy adults. Applying the oscillations at the mouth, we measured Zrs with the cheeks unsupported (Zuc) and when the subject's head and neck were enclosed in a rigid chamber completely filled with water (Zwa). We also measured Zhg with the oscillations applied around the head. Because water is incompressible, Zwa should minimize UAW shunt if not completely eliminate it. There were no significant differences in any of the AR features (e.g., location and bandwidth) of Zuc, Zsc, and Zwa. Conversely, all AR features of Zwa and Zhg were significantly different. To assess wall motion during both forms of oscillations (i.e., applied at the mouth and around the head), we measured two UAW local impedances by use of accelerometers placed on the cheeks (Zch) and submental (Zsm) region. Above 40 Hz, Zch and Zsm estimates were significantly dependent on the forcing method. Furthermore, Zch and Zsm made with the standard oscillations were consistent with the lumped UAW impedances measured with a head plethysmograph, whereas those made with the oscillations around the head were not. Therefore we conclude that, at > 32 Hz, Zsc more closely represents shunt-free impedance than does Zhg and hence should be preferred when Zrs are measured.