Narrow Results

We have investigated the short-channel effect (SCE), floating-body effect, and three-dimensional coupling effect in triple-gate MOSFET with various fin widths, gate lengths and number of fins. It is found that the SCE of these devices is alleviated as the fin width shrinks and does not depend on the number of fins. The gate-induced floating-body effect (GIFBE) is visible even in fully depleted (FD) triple-gate transistors when the film-buried oxide (BOX) interface is swept from depletion to accumulation by the back-gate bias. The 3-D coupling effect in vertical, lateral, and longitudinal directions was investigated for different channel geometries. The biasing condition which enables the simultaneous activation of all channels and gives rise to volume inversion is discussed.

In this paper, we present a coupled fluid flow and geomechanics model for simulating coalbed methane recovery. In the model, the fluid flow process is simulated with a triple porosity/dual permeability representation, and the coupling effects of effective stress and matrix swelling/shrinkage approach are simulated with a coupled fluid flow, geomechanics and gas adsorption/desorption model. The mathematical model is implemented with a fully implicit finite volume method and simulation is conducted to evaluate the effect of coupled fluid flow, geomechanics, and gas adsorption/desorption.

In this paper, a fractional-order (and an integer-order) chaotic system, obtained from Chua’s circuit by substituting Chua’s diode with two active coupled memristors (MRs) characterized by quadratic nonlinearity, is introduced to probe the memristive coupling effect. Two MRs connected in parallel are coupled by the flux. For the integer-order memristive system, the dynamical characteristics depending on the coupling strength coefficient between MRs without changing the circuit parameters are illustrated theoretically and numerically by using phase portraits, time domain diagram, bifurcation diagram and the Lyapunov diagram. Then based on the Adams–Bashforth–Moulton algorithm, the study of dynamic behavior of the fractional-order memristive system containing the time-delay reveals that appropriately setting the coupling strength between MRs generates more interesting attractors that differ from its integer-order counterpart. Besides, the effects of the order and the time-delay on dynamics are discussed briefly. Finally, the simulation results verify the validity of the theoretical analysis.

In this paper, we propose a two-dimensional (2D) boundary element method (BEM) to explore the coupling properties of two distorted graphene nanoribbons (GNRs) with wrinkles. From the calculation results, it is found that the resonant wavelengths are redshifted compared with a single GNR, and the scattering intensity is greatly increased, due to the coupling between the two GNRs. In the non-degenerate structure, the coupling resonance modes of the two GNRs are the superposition of the resonance modes of every single GNR, and the resonant wavelength and scattering intensity of different modes change differently with the gap between the two GNRs and their heights. When the coupling effect becomes stronger, some modes will split. We explain the results through the charge and current distribution of the GNRs. This work will help to understand the coupling mechanism of surface plasmon resonances of GNRs.

In this paper, the stability and evolutionary trend of Hopf bifurcations are investigated thoroughly for the double-input SEPIC DC–DC converter with one-cycle control (OCC), which is widely used in hybrid power systems. By means of cycle-by-cycle simulations, the evolutionary trend of bifurcation behaviors is identified. The inherent mechanisms of two types of bidirectional Hopf bifurcations are uncovered based on the proposed averaged model. Moreover, stability boundaries in the parameter space are derived with the help of eigenvalue analysis to optimize the circuit design. Furthermore, some important indices with respect to coupling effects are evaluated to assess the coupling effects in the system. Finally, PSpice circuit experiments are performed to verify the bifurcation analysis.

Different from single-input single-output (SISO) converters, strong nonlinear coupling effect between input ports is one of the most salient features in multi-input converters (MICs), which leads to at least three-piecewise ripple of inductor current. This paper deals with the analysis of bifurcation-based dynamical stabilities and nonlinear coupling effects in the dual-input Buck-Boost DC–DC converter. Firstly, a sampling-based averaged continuous model is proposed to describe the coupling characteristics of the dual-input DC–DC converters with three-piecewise current ripple. Based on the proposed model, the inherent mechanism of low-frequency oscillation is revealed in terms of the movement of the eigenvalue loci. It shows that Hopf bifurcation takes the responsibility for the low-frequency oscillation. Moreover, multiparameters stability boundaries are identified to establish the nonlinear mapping relations between parameter space and state space. Particularly, Gershgorin band analysis is used to give a qualitative analysis in order to evaluate the coupling effects between different state variables of the system. In addition, Gershgorin band sensitivity is proposed to reveal the influence of parameters on the coupling effects of the system. Finally, the correctness of these theoretical analyses is verified by PSpice circuit experiments. These results are beneficial to the practical optimization design as well as the understanding of coupling effect of MICs.

We propose a new broadband metamaterial perfect absorber (MPA) based on structure of metallic dishes in the THz region. It demonstrated that the coupling interaction between the central dish and adjacent dishes leads to absorption characteristics. By optimizing the geometrical structure, the bandwidth is gained up to 1.0THz with absorption better than 90%. The mechanism of the absorption results was explained by induced current, magnetic and electric distributions. Furthermore, LC equivalent circuit was used to elucidate resonant frequencies. The obtained results can provide a general guideline for fabricating broadband MPA.

A mathematical model is proposed to analyze the stability of composite shafts, considering the internal damping, transverse shear deformation and Poisson’s coupling effect at the same time. The strain–displacement relations are described using the Timoshenko beam theory, and the strain energy and kinetic energy are expressed using the weak form quadrature element method (QEM), for which each nodal point has 4 degrees of freedom. Then, the motion equation of the system is established using the Lagrange equation. The instability thresholds of the composite shaft are determined using the proposed model. The results were compared with those calculated by the equivalent modulus beam theory (EMBT), equivalent single layer theory (ESLT) and simplified homogenized beam theory (SHBT). Good agreement has been achieved. Therefore, the proposed model can be effectively used for the dynamic analysis of composite shafts.

The Bayesian model updating approach (BMUA) has been widely used to update structural parameters using modal measurements because of its powerful ability to handle uncertainties and incomplete data. However, a conventional BMUA is mainly used to update stiffness with the assumption that structural mass is known. Because simultaneously updating stiffness and mass leads to unidentifiable case or coupling effect of stiffness and mass, this assumption in conventional BMUA is questionable to update stiffness when the mass has significantly changed. This study proposes a new updating framework based on two structural systems: original and modified systems. A modified system is created by adding known mass to the original system. Different from the conventional Bayesian approach, two sets of measured vibration data in the proposed Bayesian approach are obtainable to address the coupling effect existing in the conventional Bayesian approach. To this end, a new approach reformulates the prior probability distribution function and the objective function. Two numerical simulations are considered to demonstrate the performance of the proposed approach, including (1) parameter identification, (2) posterior uncertainties, (3) probabilistic damage detections. The proposed BMUA outperforms a conventional BMUA in identifying both stiffness and mass.

In this paper, numerical simulations of ship motion coupled with LNG tank sloshing in waves are considered. The fully coupled problems are performed by our in-house RANS/DES solver, naoe-FOAM-SJTU. The internal tank sloshing and external wave flow are solved simultaneously. The considered model is a three-dimensional simplified LNG FPSO with two prismatic tanks. The ship motion responses are carried out in beam waves to compare with existing experimental data to validate this solver. The coupling effects between ship motion and sloshing tanks are observed. The anti-rolling characteristics are found, and this kind of characteristic is obvious in low-filling conditions. Different incident wave amplitudes and frequencies are considered. When the incident wave frequency is close to ship motion natural frequency, the ship motion response is strong and an overturning behavior in sloshing tanks is observed. Meanwhile, impact pressures on bulkhead are also discussed. The pressure signal explains the phenomenon in tanks we discussed before.

In this paper, the transmission mechanism of a charge-controlled water–carbon nanotubes (CNTs) fluidic transmitting nanodevice is investigated by using molecular dynamics simulation with the loading, charging and thermal effects on the starting process being considered. The results show that the external load on the driven CNT can slow down the startup speed of the nanotransmission while the transmitting stability is better than that in non-loading transmitting process. The startup speed of the water–CNTs transmission increases with the increase in the charge magnitude on CNTs since the charges on CNT atoms can increase the water–CNT interfacial coupling strength. The control of the water temperature can also affect the startup speed of the driven CNT attributed to the thermal effect on the slip velocity of confined water. The configuration, dynamic motion behaviors and temperature of the confined water in both the starting and steady transmitting processes are studied to understand the thermo-electromechanical coupling effects on the transmission mechanism of the water–CNTs charge-controlled fluidic transmitting nanodevice.

We have investigated the short-channel effect (SCE), floating-body effect, and three-dimensional coupling effect in triple-gate MOSFET with various fin widths, gate lengths and number of fins. It is found that the SCE of these devices is alleviated as the fin width shrinks and does not depend on the number of fins. The gate-induced floating-body effect (GIFBE) is visible even in fully depleted (FD) triple-gate transistors when the film-buried oxide (BOX) interface is swept from depletion to accumulation by the back-gate bias. The 3-D coupling effect in vertical, lateral, and longitudinal directions was investigated for different channel geometries. The biasing condition which enables the simultaneous activation of all channels and gives rise to volume inversion is discussed.

Elastic scattering of ⁶He on both proton and carbon targets were measured at 82.3 MeV/nucleon. For both targets, the measured differential cross sections show a large enhancement at small angles relative to the Rutherford cross section, similar to those observed at lower energies for the scattering of halo nuclei. For the proton target, the experimental results were well reproduced by optical model calculations by using the global potential KD02 with a reduction of the real part, as well as by using the microscopic JLM potential with a reduction of imaginary part. For the carbon target, the overall structure of the cross section is reasonably reproduced by the optical model calculations.