Modern Physics Letters B

Interfacial thermal conductance between dissimilar materials plays an important role in solving the overheating problem and thus improving the performance of photonic and electronic devices, especially those at micro- and nano-scale. However, conclusive heat transfer mechanism across interfaces is absent, especially across metal–nonmetal interfaces. Heat transfer across a metal–nonmetal interface is determined by the interplay among different heat carriers. In the metal, both electrons and phonons carry heat, while in the nonmetal, only the phonons are the dominant heat carriers. The interactions among these carriers can be classified into three categories, which correspond to three heat transfer channels, i.e. (i) phonon(metal)–phonon(nonmetal) interactions, which have been widely studied on the basis of the acoustic mismatch theory, diffuse mismatch model, lattice/molecular dynamics simulations; (ii) electron(metal)–phonon(metal) interactions followed by phonon(metal)–phonon(nonmetal) interactions, which were introduced to provide thermal resistance in series with that of the first channel; (iii) electron(metal)–phonon(nonmetal) direct interactions. The third channel has been introduced in order to explain the deviation between experimental results and the existing models incorporating the channel (i) and the channel (ii). Currently, there have been no models to comprehensively capture the underlying mechanism, mainly due to the difficulty in determining/defining the interfacial states at microscopic level and the temperature. Experimentally, it is hard to distinguish the contributions from these channels due to the resolution/sensitivity of the experimental system. Therefore, we here mainly concern with the investigations on the contributions of the channel (iii) from both experimental and theoretical aspects.

Super network modeling has become an effective approach for analyzing complex systems. In this study, a super network is proposed in terms of systems science. A vital aspect of the modeling is the unique dynamic mechanism of the complex system, particularly the preferential mechanism. The preferential mechanism is the driving force of system evolution. However, in current studies, preferential probability has been mostly related to node degree, and there has been little consideration of multi-attribute decision-making based on complex system characteristics (multi-level, multi-traffic, etc.). Furthermore, association analysis of driving forces and the topology structure of the complex system should be highlighted to explore the operating mechanism. In this study, we consider a complex production system (CoPS) as the research object, propose a unique learning motivation mechanism and interaction mechanism of the CoPS, develop a preferential algorithm based on the interval-valued intuitionistic uncertain linguistic (IVIUL) operator, and construct a multi-organization knowledge learning super network model. A simulation experiment was conducted to explore the effect of the preferential parameter on learning performance. The results show that the feature of the project team has an important influence on the learning improvement velocity of the super network.

Through symbolic computation with Maple, two classes of lump solutions, rationally localized in all directions in space, are presented for a new extended (2+1)-dimensional Boussinesq equation. Analyticity of the solutions is naturally achieved, and particularly, taking special choices of the involved parameters will guarantee the positiveness of the constant term in the quadratic function f. Moreover, it deserves a note that one parameter in f plays an important role in order to maintain the positiveness of the quadratic function f. As illustrative examples, two particular lump solutions with specific values of the involved parameters are worked out and their three-dimensional plots, contour plots, x-curves and y-curves are made.

In this paper, we investigate the influence of the Unruh effect on the achievement of the nonlocal advantage of quantum coherence for a two-qubit system under a relativistic frame. The results show that with the increase of acceleration, it is difficult to realize the nonlocal advantage of quantum coherence and when the acceleration exceeds a certain value, nonlocal advantage of quantum coherence cannot be realized. In addition, we explore the dynamics of Bell nonlocality, steering, quantum coherence, entanglement and quantum discord (QD) under Unruh thermal noise. It is shown that nonlocal advantage of quantum coherence, Bell nonlocality, steering and entanglement experience “sudden death” for a finite acceleration, while quantum coherence and QD vanish only in the limit of an infinite acceleration. We also find that not all nonlocal states can achieve the nonlocal advantage of quantum coherence. It is also demonstrated that the robustness of Bell nonlocality is better than nonlocal advantage of quantum coherence under the influence of the Unruh noise.

In this paper, motorized traffic flow in the vicinity of an unsignalized crosswalk on a provincial highway in China was studied. Based on the Kerner–Klenov–Schreckenberg–Wolf (KKSW) three-phase cellular automaton (CA) traffic flow model for single-lane roads, the cars’ moving rules when there were pedestrians walking on the crosswalk was redefined. A series of simulations were carried out to reveal the cars’ travel process and the influence of pedestrians crossing behavior on traffic flow. The simulations results show the redefined model can be used to study not only the characteristics of traffic flow in the vicinity of crosswalks on provincial highways but also some complex traffic problems such as traffic breakdown, synchronized flow, and moving jams. Moreover, some suggestions about signal control for the pedestrians crossing in the future were presented. Thus, this work is helpful for managing traffic flow and improving road safety and capacity in the vicinity of crosswalks on provincial highways in China.

Delafossite CuFeO${}_{2-x}$ thin films were fabricated on quartz substrate using radio-frequency sputtering deposition under low O₂ flow ratios from 9% to 0% at room temperature. The as-deposited films were in amorphous phase and crystallized into rhombohedral 3R (R3m) delafossite structure after post annealing at 900${}^{\circ }$C for 2 h in flowing N₂ atmosphere. SEM images showed that the films were composed of nano-sized crystallized grains, thin film composed of smoother surface and higher oxygen content was obtained under higher oxygen percentage in sputtering gas. The optical transmission spectra of these films were studied in the wavelength range 200–1500 nm and the results revealed a narrowing trend of direct bandgap from 3.09 eV to 2.98 eV with the decrease of oxygen flow ratio during deposition. All of the post-annealed CuFeO${}_{2-x}$ thin films exhibited p-type conductivity and linear ohmic contact feature with Cu electrodes. The carrier concentration of thin films increased from $2.8\times 10^{17}{\mathrm{\text{cm}}}^{-3}$ to $9.2\times 10^{19}{\mathrm{\text{cm}}}^{-3}$ whereas the carrier mobility decreased from $9.74{\mathrm{\text{cm}}}^2\cdot {\mathrm{\text{V}}}^{-1}\cdot {\mathrm{\text{s}}}^{-1}$ to $0.035{\mathrm{\text{cm}}}^2\cdot {\mathrm{\text{V}}}^{-1}\cdot {\mathrm{\text{s}}}^{-1}$ as the oxygen flow ratio reduced from 9% to 0%. The ability of controlling compound composition enables tuning of carrier concentration and mobility in CuFeO${}_{2-x}$ and offering essential technical basis in engineering photoelectronic devices.

A systematic investigation of structural, mechanical, elastic anisotropy and electronic properties of a recently reported novel superhard material orthorhombic $C_{20}$ ($o$-$C_{20}$) under pressure is performed utilizing the density functional theory in this work. The crystal structure parameters are obtained at zero as well as at high pressure. Pressure induced elastic constants $C_{ij}$, polycrystalline aggregate elastic modulus $(B,G,E)$, $B/G$ ratio, and Debye temperature changes for $o$-$C_{20}$ have been determined. The crystal elastic anisotropies of the ultra-incompressible $o$-$C_{20}$ are investigated in the pressure range of 0–100 GPa. The Lyakhov–Oganov model is applied to predict the hardness as functions of pressure. The calculated results reveal that $o$-$C_{20}$ possesses high elastic anisotropy under zero pressure and high pressure, and the hardness of $o$-$C_{20}$ decreases with pressure, while the Debye temperature behaves with the opposite trend. The results of electronic structure indicate that $o$-$C_{20}$ exhibits insulator characteristics, and the band gap increases with pressure. This work is expected to provide a useful guide for the future synthesis and application of $o$-$C_{20}$.

The dynamics of the tripartite thermal entanglement measured by Negativity (N) and the tripartite quantum correlation described by measurement-induced disturbance (MID) under Ornstein–Uhlenbeck noise are investigated. This study has found that the tripartite N and MID can be preserved more effectively in the non-Markovian environment than in the short-time limit and the Markov limit cases. The short-time limit is a better approximation than the Markov limit. MID vanishes only in the asymptotic limit, while entanglement sudden death may occur, and the decreasing duration of MID far outweighs entanglement. This implies that MID is more robust than Negativity. As the noise bandwidth increases, the disentanglement time and the decay time of MID are significantly shorter. The increase of XZX+YZY three-site interaction is more effective than XZY−YZX three-site interaction to enhance Negativity and MID as well as the disentanglement time. The magnetic field diminishes Negativity and MID, but has no significant influence on the decreasing durations of both Negativity and MID.

Drivers would adjust the speeds in response to not only the external environment, but also the anticipated traffic condition. In this paper, we propose a new continuum model considering the driver’s self-anticipative effect. Such effect is mainly reflected by the difference between the current speed and optimal speed within the anticipation time step. By applying the linear stability theory, the stability condition of the new model is obtained. Through the nonlinear analysis method, the KdV–Burgers equation of the model is provided. The solution describes the evolution of density waves near the neutral stability region. The simulation example verifies that the self-anticipative effect of the driver contributes to suppressing traffic congestion and reducing exhaust emissions effectively. We thus suggest that the traffic flow stability could be improved in an ad hoc manner.

In this study, the Lie symmetry method is used to perform detailed analysis on the modified Zakharov–Kuznetsov equation. We have obtained the infinitesimal generators, commutator table of Lie algebra and symmetry group. In addition to that, optimal system of one-dimensional subalgebras up to conjugacy is derived and used to construct distinct exact solutions. These solutions describe the dynamics of nonlinear waves in isothermal multicomponent magnetized plasmas.

Speaker recognition is the technique to identify the identity of a person from statistical features obtained from speech signals. Many speaker recognition techniques have been designed and implemented so far to efficiently recognize the speaker. From the existing review, it is found that the existing speaker recognition techniques suffer from the over-fitting issues. Therefore, to overcome the over-fitting issue in this paper, we design, a novel ensemble-based quantum neural network. It selects one base model (i.e. expert) for each query, and concentrates on inductive bias reduction. A set of quantum neural networks are trained by considering different kinds of quantum features and are afterwards used to recognize the speaker. In the end, ensembling is used to combine these classification results. Extensive experiments have been carried out by considering the proposed technique and existing competitive machine learning-based speaker recognition techniques on speaker recognition data. It is observed that the proposed technique outperforms existing speaker recognition techniques in terms of accuracy and sensitivity by 1.371% and 1.291%, respectively.

In this paper, a novel astrophysics-based approach is proposed for automatically finding the clusters and features simultaneously. A novel agent encoding scheme is used to encode both the number of clusters and features. A novel dynamic threshold technique is proposed for an efficient searching. The validation of proposed technique is tested on eight real-life data sets. The statistical significance of proposed technique is attributed by statistical tests. It is also applied on solving image segmentation and microarray data analysis problems. Experimental results reveal that the proposed technique outperforms the other competitive approaches.

We propose and investigate a polarization-independent high-efficiency encapsulated subwavelength grating with a connecting layer in this paper. Numerical simulated method of rigorous coupled-wave analysis is adopted for optimization. Based on the simulated precise results, a simplified modal method is used to give perspicuous physical propagating fundamentals and explain wideband performance in the grating, where the coupled efficiencies by means of the simplified modal method are to be in conformity with the calculated values of the rigorous coupled-wave analysis for TE and TM polarizations. Compared with the researched surface-relief polarization-independent single-port grating, efficiencies are improved with 98.1% for TE polarization and 98.2% for TM polarization. Hence, the novel gratings with some superiorities are suitable for promising photonic devices.

In this paper, the exact solutions to the (2+1)-dimensional extended shallow water wave (SWW) equation are investigated by using its bilinear form and ansatz techniques. Following the method given by Ma [Phys. Lett. A 379 (2015) 1975–1978], two classes of lump solutions are constructed by searching for positive quadratic function solutions to the associated bilinear equation. Furthermore, two kinds of interaction solutions between a lump and solitary waves are presented by taking the solution of the associated bilinear equation as a linear combination function of a quadratic function and the double exponential function, one of which is the interaction solution between a lump and an exponentially decayed soliton, and the other one is the interaction solution between a lump and an exponentially decayed twin soliton. Finally, some figures are given to illustrate the dynamic properties of these obtained solutions.