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We investigate the finite size effects of a three-dimensional second-order topological insulator with fourfold rotational symmetry and time-reversal symmetry. Starting from the effective Hamiltonian of the three-dimensional second-order topological insulator, we derive the effective Hamiltonian of four two-dimensional gapped surface states by perturbative methods. Then, the sign alternation of the mass term of the effective Hamiltonian on the adjacent surface leads to the hinge state. In addition, we obtain the effective Hamiltonian and its wave function of one-dimensional gapless hinge states with semi-infinite boundary conditions based on the effective Hamiltonian of two-dimensional surface states. In particular, we find that the hinge states on the two sides of the same surface can couple to produce a finite energy gap. [ABSTRACT FROM AUTHOR]

We have studied in detail the influence of same-orbit and different-orbit hopping disorders in HgTe/CdTe quantum wells. Intriguingly, similar to the behavior of the on-site Anderson disorder, a phase transition from a topologically trivial phase to a topological phase is induced at a proper strength of the same-orbit hopping disorder. For different-orbit hopping disorder, however, the phase transition does not occur. The results have been analytically verified by using effective medium theory. A consistent conclusion can be obtained by comparing phase diagrams, conductance, and conductance fluctuations. In addition, the influence of Rashba spin-orbit interaction (RSOI) on the system has been studied for different types of disorder, and the RSOI shows different influence on topological phase at different disorders. The topological phase induced by same-orbit hopping disorder is more robust against the RSOI than that induced by on-site Anderson disorder. For different-orbit hopping disorder, no matter whether the RSOI is included or not, the phase transition does not occur. The results indicate, whether or not the topological Anderson insulator can be observed depends on a competition between the different types of the disorder as well as the strength of the RSOI in a system. [ABSTRACT FROM AUTHOR]

Tremendous efforts have been dedicated to developing sorbents for water remediation due to their high efficiency and non-secondary pollution. However, the majority of sorbents still face the challenges of complex processing, low mechanical strength and volume absorption. Hence, the functional hydrothermal carbonization coatings (HTCCs) were prepared on carbon fibers in carbon fiber braid via a facile hydrothermal carbonization process of widely sourced carbohydrate to obtain a robust sorbent, which possessed the controllable microstructure and composition for various requirements of water remediation. The gradient surface structure of carbon fiber braid with interior smooth coatings carbon fibers and exterior rough surface could be fabricated at pH value of 1. The HTCCs-carbon fiber braid had superior yield strength and compressive strength. By regulating the reaction process, the yield strength could range from 0.044 MPa to 0.235 MPa and the max compressive strength change from 0.198 MPa to 1.113 MPa. The HTCCs-carbon fiber braid showed excellent adsorption for Rhodamine B with a high removal degree of 98.5%, which kept more than 90% even after 10 squeezing adsorption cycles. The HTCCs-carbon fiber braid could be adjusted to effectively absorb oil pollutants from water by a facile heat treatment. After heat treatment, the HTCCs-carbon fiber braid exhibited excellent volume absorption capacity for contaminants, which could change from 83.9% to 88.5%. Thus, the HTCCs-carbon fiber braid prepared by a green, high-efficiency and low-cost process has great potential for sorption multiple contaminations in water by virtue of the combination of controllable carbonaceous coatings and robust carbon fiber braid. [ABSTRACT FROM AUTHOR]

Naturally occurring indole alkaloids are ubiquitously present in nature and possess extensive biological properties and structural diversity. Mechanistically, naturally occurring indole alkaloids have the potential to inhibit cancer cell proliferation, arrest cell cycle and induce apoptosis. Accordingly, naturally occurring indole alkaloids exhibit promising activity against both drug-sensitive and drug-resistant cancers including multidrug-resistant forms. Therefore, naturally occurring indole alkaloids constitute an important source of anticancer drug leads and candidates. The goal of this review is to highlight the current scenario of naturally occurring indole alkaloids with anticancer potential, covering articles published from 2018 to present. The names, sources, and antiproliferative activity are discussed to continuously open up a map for the remarkable exploration of more effective candidates. The goal of this review is to highlight the current scenario of naturally occurring indole alkaloids with anticancer potential, covering articles published from 2018 to present. [Display omitted] [ABSTRACT FROM AUTHOR]

Performing the non-equilibrium Green's function method, we calculate the Seebeck coefficient (S) and the thermoelectrical figure of merit (Z T) in the quantum anomalous Hall insulator-topological superconductor-quantum anomalous Hall insulator hybrid structure with temperature gradient. It is found that a high thermoelectrical figure of merit can be achieved with the helical topological superconductor phase. The S and the Z T are mainly affected by the temperature and the device size. At a certain temperature and the right device size, the Seebeck coefficient and the figure of merit can reach very high values. [ABSTRACT FROM AUTHOR]

A novel control scheme is proposed to improve the yaw stability of a tractor semitrailer vehicle in critical situations. The control scheme is a two-layer structure consisting of an upper yaw moment controller and a lower brake force distributor. The tractor and the trailer are, respectively, stabilized by two independent fuzzy logic based yaw moment controllers. The controllers for the tractor and the trailer are, respectively, designed to track the reference yaw rate of the tractor and the hitch angle between the tractor and the trailer while considering the variation of the hitch angular rate at the same time. The corrective yaw moments determined by the corresponding upper fuzzy yaw moment controllers are realized by active wheel braking. The performance of the proposed control scheme is evaluated by simulations on a nonlinear vehicle model. The results demonstrate that the proposed control scheme is robust and effective in stabilizing the severe instabilities such as jackknife and trailer oscillation in the chosen simulation scenarios. It is believed that this control scheme is robust to the variation of road adhesion conditions. [ABSTRACT FROM AUTHOR]

The Seebeck effect in graphene with uniform Kekulé lattice distortion has been studied using the tight-binding model combined with the nonequilibrium Green's function method. The numerical results of this work show that the Seebeck coefficient of the O-shaped Kekulé graphene can be enhanced by modulating the gate voltage. At room temperature (T ≈ 300 K), the Seebeck coefficient for the armchair nanoribbon is S c ≈ 1370 μV/K and for the zigzag nanoribbon is S c ≈ 1260 μV/K. At low temperature (T ≈ 128 K), the Seebeck coefficient for the armchair nanoribbon is S c ≈ 2500 μV/K. In addition, the nano-structuration of the O-shaped Kekulé graphene layer induces an anisotropic behavior in the Seebeck effect. Our work provides an idea for the fabrication of efficient and controllable thermoelectric effect devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Recent advances on alkali-metal ion batteries are reviewed for CrB 4 and MoB 4 monolayer. • Metal-ion adsorption, diffusion, storage capacity and charge/discharge are discussed. • Metallicity remains well maintained throughout the adsorption process. • Excellent stability during lithiation, sodiation, and potassiation, demonstrating its potential for practical applications in advanced battery systems. Finding high-storage-capacity anode materials has been a focus of ion-battery research. Two-dimensional (2D) materials have shown promise as high-performance electrode-materials as they have developed gradually. Here we examined the viability of 2D CrB 4 and MoB 4 monolayers as optimal anode-materials for Li/Na/K ion batteries using first-principles DFT calculations. Preliminary investigations showed that both materials exhibited thermodynamic, structural, and mechanical stability. We found that a strongly negative adsorption energy can help in stabilizing the adsorption of metal-ions on materials surface instead of clustering, that ensures metal-ion-batteries stability. The maximum theoretical storage capacities of Li, Na, and K ions adsorbed on the CrB 4 monolayer surface were 1689,1126 and 750 mA h g−1, respectively, while those on the surface of MoB 4 were 1155,770 and 513 mA h g−1, respectively. Additionally, calculated open-circuit voltages for Li-ions (0.84,0.82 V), Na-ions (0.25,0.32 V), and K-ions (0.85,0.81 V) for CrB 4 and MoB 4 monolayers, respectively. Electronic properties showed that increasing the metal ions concentration enhanced both materials' electrical conductivity and remained the metallic in nature after adsorption. However, Li/Na/K energy barriers are nevertheless consistent with various typical 2D anode materials. The light shaded on 2D MoB 4 and CrB 4 is anticipated to identify new anode materials for LIBs, NIBs, and KIBs. [ABSTRACT FROM AUTHOR]

The Nernst and Seebeck effects in graphene with uniform Kekulé lattice distortion have been studied using the tight-binding model combined with the nonequilibrium Green's function method. Numerical results of this work showed that due to the electron–hole symmetry, the Nernst coefficient is an even function of the Fermi energy, while the Seebeck coefficient is an odd function regardless of the magnetic field. The Nernst and Seebeck coefficients show peaks when the Fermi energy crosses the Landau levels at high magnetic fields or crosses the transverse subbands at the zero magnetic fields. The peak height can be very large when the Fermi energy approaches the Dirac point, the Seebeck coefficient can reach about 0.78 mV/K, and the Nernst coefficient can reach about 0.95 mV/K at the corresponding hopping energy modification parameter δ = 0.03 and T = 0.009 t / k B ≈ 288 K. When δ = 0.08 and T = 0.024 t / k B ≈ 766 K, the Seebeck coefficient (or Nernst coefficient) is still up to about 0.78 mV/K (or 0.95 mV/K). This suggests that tunable Seebeck and Nernst coefficients can be achieved because the bandgap is a function of the corresponding hopping energy modification parameter δ. Experimentally, δ can be modulated by changing the type and amount of atoms adsorbed on graphene. In strong magnetic fields, the Nernst coefficient does not depend on the chirality of the nanoribbon. [ABSTRACT FROM AUTHOR]

As a rapidly evolving 2D monolayer material, tungsten tetraboride MBene exhibits innate advantages in electrochemical applications because of its unique graphene-like structure and metallic properties. In this study, we utilized first-principles calculations to identify the potential applications of WB 4 as an anode material in rechargeable alkali-metal-ion batteries. The findings imply that the Li, Na, and K adsorption on the WB 4 surface results in exceptionally high conductivity, and the WB 4 monolayer can effectively adsorb these ions with significant adsorption energies of −2.516 eV, −2.356 eV, and −2.941 eV for Li, Na, and K ions, respectively. The results indicate that WB 4 exhibits excellent stability during lithiation, sodiation, and potassiation. Notably, we propose high storage capacities for LIBs (708mAh/g), SIBs (472mAh/g), and KIBs (177 mAh/g), with maintained structural stability for the adsorption of these metal ions. The measured average open circuit voltages for WB 4 were found to be 0.77 V (Li), 0.73 V (Na), and 0.80 V (K), and metallicity remain good maintained within the entire adsorption process. The calculated migration energy barriers for Li, Na, and K were 0.47 eV,0.21 eV and 0.13 eV respectively. The notable properties of WB 4 make it an advantageous electrode material for alkali-metal ion batteries. [Display omitted] • This research investigates recent advancements in alkali-metal ion batteries, focusing on WB 4. • Key aspects such as metal-ion adsorption, diffusion, storage capacity, and charge/discharge processes are examined. • The material upholds its metallicity consistently throughout the adsorption stages. • WB 4 showed remarkable stability during lithiation, sodiation, and potassiation, highlighting its significant potential for practical use in advanced battery systems. [ABSTRACT FROM AUTHOR]

We consider a ring geometry with a quantum dot (QD) embedded in one of its arms, which is coupled symmetrically to two normal leads and threaded by Aharonov-Bohm (AB) flux φ. The QD is coupled to a topological nanowire. Using scattering matrix method, the differential conductance and current cross correlation are investigated. By varying the external magnetic field strength and the coupling strength between the QD and Majorana bound state (MBS), the zero-bias conductance peak (ZBCP) will split and oscillate due to the overlapping of the two MBSs. Due to the sum rule in a pair of well-separated MBSs, the total differential conductance at zero bias voltage is quantized to 2 e 2/ h. The total differential conductance and the current cross correlation show the periodicity of π with zero QD energy level and 2 π with nonzero QD energy level. • The differential conductance and the current cross correlation in an AB ring with QD embedded in one of its arms are investigated. • The zero-bias conductance peak split and oscillate due to the overlapping of the two MBSs. • The total differential conductance and the current cross correlation show the periodicity of π with zero QD energy level. [ABSTRACT FROM AUTHOR]

Smooth, uniform and controllable hydrothermal carbon coatings (HTCCs) had been successfully constructed on the carbon fibers through the efficient hydrothermal transformation approach from renewable carbohydrate. The thickness of HTCC could be effectively tailored from nano-scale to micro-scale by just adjusting the concentration of carbohydrate solution and the oxygen content in the HTCC could be significantly controlled through the high-temperature treatment. As for the growth model of the HTCC, FeCl 3 played a critical role in improving the transformation from glucose to the dehydrated intermediate, mainly composed of 5-hydroxymethylfurfural (HMF), and promoting the conversion from HMF to carbonaceous structure, subsequently. The efficient and scalable preparation route not only offered promising prospects for radically substituting the traditional methods to prepare the carbon coating, but also provided a novel surface modification strategy of carbon fibers in the fields of carbon fiber reinforced composites and flexible textile electronic devices. Unlabelled Image • Multiscale thickness carbon coating had been prepared by the environmental and low-cost carbohydrates as raw material. • The formation process of hydrothermal carbon coatings was investigated based on the comparison experiment. • The novel route made the fiber coating promising candidate for the application of composites and energy storage. [ABSTRACT FROM AUTHOR]

Performing the scattering matrix approach, we calculate the current noise cross correlation and the differential conductance in the Majorana bound states (MBSs) comb. The teeth on the comb consist of topological super-conducting nanowire sandwiched between two quantum dots (QDs). We find that the nonlocal property of MBSs comb can be effectively modulated by the quantum dots. For only one "QD-MBSs-QD" building block, N = 1, the current noise cross correlation is negative at small bias and becomes positive at lager bias. A zero bias conductance peak of 2 e 2/ h can be found, and it splits with ϵ u increasing, where ϵ u is the energy level of up-part QD. For N ≥ 2, the current noise cross correlation is zero at small bias and becomes positive at larger bias. Different from the case of N = 1, the zero bias conductance peak is 4 e 2/ h due to the local Andreev reflection. Besides, we find that the differential conductance is robust against the influence of N. • The current noise cross correlation and the differential conductance in the Majorana bound states (MBSs) comb are investigated. • The MBSs comb can be effectively modulated by the up-part quantum dots due to the effective resonance between the Majorana bound state and the dot. • For only one "QD-MBSs-QD" building block, N = 1, a zero bias conductance peak of 2 e 2/ h can be found. For N = 2, the zero bias conductance peak is 4 e 2/ h. [ABSTRACT FROM AUTHOR]