Resonant Branch Research Articles

Visualization of spin-polarized surface resonances in Pb-based ternary topological insulators

The formation of the topological surface state originates from bulk band inversion at the top of the valence band and the bottom of the conduction band. The transition between normal and topological insulators is known as a topological phase transition. Here we show spin-polarized electronic states of Pb-based ternary topological insulators Pb(Bi1-xSbx)2Te4 (x = 0.55, 0.70, 0.79) investigated by spin- and angle-resolved photoemission spectroscopy and first-principles calculations. We visualize a pair of spin-polarized surface resonances dispersing along the upper edge of projected bulk bands in occupied states. Interestingly, a branch of the spin-polarized surface resonances continuously connects to the topological surface state. The coexistence of the topological surface state and the spin-polarized surface resonances can be explained by considering the topological phase transition.

Resonant soliton interaction for the Date-Jimbo-Kashiwara-Miwa equation

Investigated in this paper is the resonant soliton interactions for the (2+1)-dimensional Date-Jimbo-Kashiwara-Miwa equation. A comprehensive classification of these interactions is presented, based on the exact expression of resonant soliton branches derived from asymptotic analysis. Two types of resonant interactions between two solitons are identified, characterized by the parameter Aij, which directly determines the phase shift. One-resonant and two-resonant three-soliton interactions are discussed, in which certain new soliton branches are revealed. Some graphical analyses are provided to illustrate these resonant interactions.

An improved soft-switching inverter to eliminate pre-charge current

To address the current stress problem brought on by the auxiliary resonant pole inverter’s pre-charge state, this paper gives an improved auxiliary circuit based on the original inverter. The improved circuit avoids a pre-charge state by adding auxiliary capacitors to form a resonant branch. In contrast to the original inverter, this inverter lowers the current stress on both the auxiliary and primary switches by resolving the pre-charge state’s current stress issue. As a result, the inverter’s losses are decreased, which raises the system’s efficiency. The working principle of this inverter is given in the paper. After a comparison and analysis of the inverter’s pre-charge state, an experiment is used to confirm the device’s viability.

Dual LC parallel multi‐resonant DC‐DC converter with wide output‐voltage range

SummaryAlthough LLC converters have widespread applications due to their advantages of high efficiency, high power density, and soft switching, in wide voltage gain range applications, a large switching frequency range is inevitably required, which may bring difficulties in converter design and efficiency improvement. In this paper, a dual LC parallel multi‐resonant converter (MRC) is introduced. The converter contains two parallel LC resonant branches in the resonant tank, which exhibit the notch filter characteristic on the gain curve. It enables the converter to provide wide voltage gain regulation, soft startup, and overcurrent protection over a limited frequency range. Compared to other five‐element MRCs, since the converter provides different current loops for the fundamental wave and the third harmonic to transmit active power, the circulating reactive energy and stress on the resonant components are reduced. Finally, a detailed design procedure for a 3.3 kW converter prototype with an output voltage range of 250–450 V is provided.

Study on a Modified CLLC Converter Paralleling a Resonant Branch With the Transformer for Wide Voltage Range Applications

Study on a Modified CLLC Converter Paralleling a Resonant Branch With the Transformer for Wide Voltage Range Applications

Current Sharing for a Multiphase Inverter Based on Coupled External Parallel Resonant Branches for Wireless Power Transfer System

Current Sharing for a Multiphase Inverter Based on Coupled External Parallel Resonant Branches for Wireless Power Transfer System

Nonlinear analysis and vibro-impact characteristics of a shaft-bearing assembly

This study investigates the nonlinear frequency response of a shaft-bearing assembly with vibro-impacts occurring at the bearing clearances. The formation of nonlinear behavior as system parameters change is examined, along with the effects of asymmetries in the nominal, inherently symmetric system. The primary effect of increasing the forcing magnitude or decreasing the contact gap sizes is the formation of grazing-induced chaotic solution branches occurring over a wide frequency range near each system resonance. The system's nominal setup has very hard contact stiffness and shows no evidence of isolas or superharmonic resonances over the frequency ranges of interest. Moderate contact stiffnesses cause symmetry breaking and introduce superharmonic resonance branches of primary resonances. Even if some primary resonances are not present due to the system's inherent symmetry, their superharmonic resonances still manifest. Branches of quasiperiodic isolas (isolated resonance branches) are also discovered, along with a cloud of isolas near a high-frequency resonance. Parameter asymmetries are found to produce a few significant changes in behavior: asymmetric linear stiffness, contact stiffness, and gap size could affect the behavior of primary resonant frequencies and isolas.

IFD-MDCN: Multibranch denoising convolutional networks with improved flow direction strategy for intelligent fault diagnosis of rolling bearings under noisy conditions

Rolling bearings are the core components of rotating machinery, and their normal operation is crucial to the entire industrial production. Most existing condition monitoring methods have been devoted to extracting discriminative features from vibration signals that reflect bearing health status information. However, the complex working conditions of rolling bearings often make the periodic impulsive characteristics related to fault information easily buried in noise interferences. Therefore, it is challenging for existing approaches to learning discriminative fault-related features in these scenarios. To address this issue, a novel multibranch CNN named IFD-MDCN is developed in this paper, which represents multibranch denoising convolutional networks (MDCN) with an improved flow direction (IFD) strategy. The main contributions of this research work include: 1) designing a multiscale denoising branch to extract multi-level information and reduce noise information. More specifically, the multiscale denoising branch adopts a Gaussian multi-level noise reduction procedure to represent vibration signals at multiple levels and filter out the noise components, and then it uses a multiscale convolutional module to extract abundant features from these denoised signal representations; 2) establishing an improved flow direction strategy-based adaptive resonance branch to learn periodic impulsive features associated with fault information from vibration signals. Extensive experimental results reveal that the IFD-MDCN outperforms five state-of-the-art approaches, especially in strong noise scenarios.

A ground fault section location method based on active detection approach for non-effectively grounded DC distribution networks

Identifying and locating the single-pole-to-ground fault for the non-effectively grounded DC distribution networks is highly challenging due to the topology arrangement limitations and the grounding mode. To solve this problem, a ground fault section location method based on active detection approach is proposed. Firstly, an approach based on an additional control strategy in coordination with a resonant branch setup is proposed to inject the detection signals. Then, the parameters of the resonant branch and the detection signals to be injected are obtained after careful consideration to ensure the optimal distribution characteristics of the injected signals. Finally, a protection principle based on a coordinating time interval scheme is proposed to locate and isolate the fault section according to the single terminal information. Simulation results show that the proposed method achieves excellent performance.

New insights into the pole parameters of the Λ(1380), the Λ(1405) and the Σ(1385)

A coupled-channel S- and P-wave next-to-leading order chiral-unitary approach for strangeness S = −1 meson-baryon scattering is extended to include the new data from the KLOE and AMADEUS experiments as well as the Λπ mass distribution of the Σ(1385). The positions of the poles on the second Riemann sheet corresponding to the Σ(1385) pole and the Λ(1380) and Λ(1405) poles as well as the couplings of these states to various channels are calculated. We find that the resonance positions and branching ratios are on average determined with about 20% higher precision when including the KLOE and AMADEUS data. Additionally, for the first time, the correlations between the parameters of the poles are investigated and shown to be relevant. We also find that the Σ(1385) has negligible influence on the properties of the Λ states given the available data. Still, we identify isospin-1 cusp structures in the present solution in light of new measurements of π±Λ line-shapes by the Belle collaboration.

Combined wave emission system based on dual resonance method for airborne transient electromagnetic detection

To improve the detection efficiency of airborne transient electromagnetic method (ATEM) and reduce the times of flight experiments, a dual resonance-based combined wave emission circuit is proposed in this paper, which realizes the combined emission of half-sine wave and triangular wave through the selection of different resonant branches. Based on the operating principle of the proposed emission circuit, the model of second-order resistor-inductor-capacitor equivalent circuit is established. Then, the generation process of the combined wave is analyzed, and the segmentation control method is proposed. Finally, the feasibility and effectiveness of the proposed combined wave emission system are verified by simulation model building and prototype testing, and the results show that the emission current has good quality and high stability. Compared with the traditional emission of single wave current, the combined wave current has the advantages of large magnetic moment of half-sine wave and rich high-frequency components of triangular narrow pulse, which can effectively expand the detection range and improve the measurement efficiency of ATEM.

Resonant solitons of the B-type Kadomtsev-Petviashvili equation

In this letter, we study the resonant soliton interactions for the B-type Kadomtsev-Petviashvili equation. For the interaction between two solitons, we obtain two kinds of resonant interaction in terms of the value of Aij which determines the interaction intensity. Using the asymptotic analysis, we derive the exact expression of resonant soliton branch. One-resonant three soliton interaction is also discussed. Some graphic analysis are discussed to show these resonant interactions.

Filtering Power Divider Design Using Resonant LC Branches for 5G Low-Band Applications

This paper proposes an ultra-compact filtering power divider with a wide harmonic suppression band. In this design, the proposed power divider (PD) in the ideal case has 100% size reduction and an infinite number of harmonics suppression. However, in the real case, the proposed divider has a 92% size reduction and suppresses the 2nd to 45th harmonics. The small-proposed divider is designed at 0.9 GHz. The typical Wilkinson divider has two long quarter-wavelength branches. In the proposed design, new resonant series LC branches are used instead of the divider’s typical branches, leading to performance improvements in the proposed PD. To the best of the authors’ knowledge, the proposed filtering PD has the best size reduction, and harmonics suppression reported thus far. The proposed divider has a filtering response with good insertion loss at the passband, which is desirable for modern communication systems.

An extended KdV6 hierarchy of nonlinear evolution equations: Painlevé integrability and variety of branches of resonances

PurposeThe purpose of this paper is to study an extended hierarchy of nonlinear evolution equations including the sixth-order dispersion Korteweg–de Vries (KdV6), eighth-order dispersion KdV (KdV8) and many other related equations.Design/methodology/approachThe newly developed models have been handled using the simplified Hirota’s method, whereas multiple soliton solutions are furnished using Hirota’s criteria.FindingsThe authors show that every member of this hierarchy is characterized by distinct dispersion relation and distinct resonance branches, whereas the phase shift retains the KdV type of shifts for any member.Research limitations/implicationsThis paper presents an efficient algorithm for handling a hierarchy of integrable equations of diverse orders.Practical implicationsMultisoliton solutions are derived for each member of the hierarchy, and then generalized for any higher-order model.Social implicationsThis work presents useful algorithms for finding and studying integrable equations of a hierarchy of nonlinear equations. The developed models exhibit complete integrability, by investigating the compatibility conditions for each model.Originality/valueThis paper presents an original work with a variety of useful findings.

Flexural–flexural internal resonances 3:1 in initially straight, extensible Timoshenko beams with an axial spring

This work investigates the dynamics of a hinged–simply supported beam with an axial spring in the neighbourhood of a 3:1 internal resonance between two successive transversal vibration modes. Multiple time scale method is applied to the analytical model of the planar extensible-shearable beam with associated boundary conditions, and a second order approximate solution is obtained. The phenomena that we investigate occur on the resonant branch of the frequency response curve around the main natural frequency, and consists of a localized extra (bent) peak on that branch. Also some detached branches have been theoretically detected in the neighbourhood of this extra peak. The analytical frequency response curves are analysed extensively and have been compared with finite element numerical simulations, finding an overall good agreement. Stability of the analytical solutions is checked by computing the eigenvalues of the Jacobian matrix and looking at the sign of their real part. Strain energies due to flexural, axial, shear deformability and axial spring are determined and compared between each other to ascertain their relative importance.

Periodic Motion and Frequency Energy Plots of Dynamical Systems Coupled With Piecewise Nonlinear Energy Sink

Abstract The frequency-energy plots (FEPs) of two-degree-of-freedom linear structures attached to a piecewise nonlinear energy sink (PNES) are generated here and thoroughly investigated. This study provides the FEP analysis of such systems for further understanding to nonlinear targeted energy transfer (TET) by the PNES. The attached PNES to the considered linear dynamical systems incorporates a symmetrical clearance zone of zero stiffness content where the boundaries of the zone are coupled with the linear structure by linear stiffness elements. In addition, linear viscous damping is selected to be continuous during the PNES mass oscillation. The underlying nonlinear dynamical behavior of the considered structure-PNES systems is investigated by generating the fundamental backbone curves of the FEP and the bifurcated subharmonic resonance branches using numerical continuation methods. Accordingly, interesting dynamical behavior of the nonlinear normal modes (NNMs) of the structure-PNES system on different backbones and subharmonic resonance branches has been observed. In addition, the imposed wavelet transform frequency spectra on the FEPs have revealed that the TET takes place in multiple resonance captures where it is dominated by the nonlinear action of the PNES.

A Fixed Frequency Zero-Voltage-Switching On-Board EV Charger

For electric vehicle (EV) onboard charging, high efficiency and power density of the charger is required. Soft switching technique is an effective way to increase On-Board Charger (OBC) power density and efficiency. This paper presents a fixed frequency zero-voltage-switching OBC topology which can realize Zero-Voltage-Switching (ZVS) of all the power semiconductor devices. An auxiliary resonant branch is used to realize Zero-Voltage-Switching for both front-end full-bridge rectifier and phase-shift full-bridge dc-dc converter. A novel PWM scheme is proposed for the OBC topology. ZVS conditions are derived. Finally, the proposed OBC is verified by the experiment.

A novel miniaturized gain‐enhanced antipodal Vivaldi antenna with back radiation reduction

AbstractIn this paper, a novel miniaturized planar antipodal Vivaldi antenna (AVA) with high gain and back radiation reduction for 5G millimeter‐wave (mm‐Wave) communication is presented. First, due to the use of the gradual corrugated edges (GCE), the operating band of the antenna is extended in the direction of lower frequencies and the overall gain is also improved as well. Second, its gain of the antenna is better enhanced at the high frequency band through I‐Shape Metal Director (IMD). Lastly, to further reduce the back radiation, the split ring resonance branches (SRB) are added to the ground. The antenna front‐back ratio has improved considerably to over 20 dB. Meanwhile the antenna gain is improved further. Furthermore, a prototype antenna array was fabricated and the measurement results clearly show that the antenna array gain varies in the range of 15.86–16.43 dB when operating in the 5G millimeter wave band (24.75–28.35 GHz).

THE STUDY OF THE INFLUENCE OF X-RAY IRRADIATION ON DISLOCATION CHARACTERISTICS IN LiF CRYSTALS

The dependences of the absorption α and the ultrasound velocity in LiF single crystals with residual deformation ε = 0.65% at 300 K in the range of radiation doses 0...1057 R were studied using the acoustic pulse echo method at a frequency of 7.5 MHz. Based on the results of measurements of the acoustic characteristics, the absolute values of the parameters of the dislocation structure – the average effective length of the dislocation loop L and the dislocation density Λ and their dependences on the irradiation time are determined. The calculated characteristics are compared with the previously obtained results for the high-frequency branch of the damped dislocation resonance and using the selective etching method. The revealed noticeable discrepancy in the values of these parameters is explained by the impossibility of describing a single attenuation mechanism for acoustic measurements carried out in a wide frequency range.

Direct measurement of the resonance strengths and branching ratios of low-energy (p, γ) reactions on Mg isotopes * *Supported by the National Natural Science Foundation of China (11490563, 11961141003) and the Continuous Basic Scientific Research Project (WDJC-2019-13)

Proton capture reactions on Mg isotopes are significant in the Mg-Al cycle in stellar H-burning. In particular, the resonance strengths and branching ratios of low-energy resonances in 25Mg( )26Al reactions determine the production of 26Al, which is one of the most important long-lived radioactive nuclei in nuclear astrophysics. In this article, we report our first experiment using the intense proton beam of approximately 2 mA provided by the JUNA accelerator ground laboratory and a new technique that can minimize the composition change of targets under intense beam irradiation. The resonance strengths and branching ratios of E = 214, 304, and 326 keV resonances in the reactions of 24Mg( )25Al, 25Mg( )26Al, and 26Mg( )27Al, respectively, were measured with high accuracy. The success of this experiment provides a good calibration for the nuclear astrophysical experiment at the Jinping underground laboratory.