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In this work, tB-MoS2 and MoSe2 flower-like structures were produced using a CVD method. An indirect-to-direct energy band gap transition was shown in the region away from the flower center in the structures, accompanied by an enhanced PL intensity.

Here, we use KPFM to directly distinguish AB-BLG (BLG), ABA-TLG (TLG), and twisted bilayer graphene (tBLG). Furthermore, we have explored the relationship between the surface potential and the different twist angles of tBLG.

Aconiti Kusnezoffii Radix (Caowu) is often combined or processed with Chebulae Fructus (Hezi) to achieve attenuation purposes in Mongolian medicine. Mesaconitine (MA), a main bioactive ingredient of Caowu, is also famous for its high cardiotoxicity while exerting good anti-inflammatory and analgesic properties. Gallic acid (GA), one of the leading chemical components in Hezi, possesses cardiac protection. This study aimed to clarify the detoxification effects of GA from Hezi on MA-induced cardiotoxicity and whether the detoxification mechanism is related to the TRPV1 channel. Cell viability was determined by methyl thiazol tetrazolium (MTT), and lactate dehydrogenase (LDH) leakage rate was determined by ELISA. Hoechst 33258, JC-1, DCFH-DA, and Fluo-3 AM staining were conducted to detect apoptosis, mitochondrial membrane potential, reactive oxygen species (ROS), and Ca2+ respectively; TRPV1 channel current was recorded by whole-cell patch-clamp technology to observe the effect of GA and MA alone or in combination on TRPV1 channel. The results showed that GA exhibited pronounced detoxification effects on MA-induced cardiotoxicity. GA significantly inhibited the MA-induced decrease in cell viability; suppressed the MA-induced LDH leakage rate, apoptosis, and the release of ROS and Ca2+; and alleviated the reduction of mitochondrial membrane potential. We found that MA-induced cardiotoxicity was significantly attenuated in H9c2 cells pretreated with the TRPV1 antagonist BCTC. In the whole-cell patch-clamp experiment, the TRPV1 channel current increase was caused by the GA and MA treatment, whereas it was reduced by the cotreatment of GA and MA. Our data demonstrate that GA in Hezi can reduce MA-induced cardiotoxicity by inhibiting intracellular Ca2+ influx, restoring mitochondrial membrane potential, and reducing apoptosis. The detoxification mechanism may be related to the desensitization of the TRPV1 channel by the combined application of MA and GA.

Scanning probe microscopy (SPM) allows the spatial imaging, measurement, and manipulation of nano and atomic scale surfaces in real space. In the last two decades, numerous advanced and functional SPM methods, particularly atomic force microscopy (AFM), have been developed and applied in various research fields, from mapping sample morphology to measuring physical properties. Herein, we review the recent progress in functional AFM methods and their applications in studies of two-dimensional (2D) materials, particularly their interfacial physical properties on the substrates. This review can inspire more exciting application works using advanced AFM modes in the 2D and functional materials fields.

Transition-metal chalcogenides (TMCs) materials have attracted increasing interest both for fundamental research and industrial applications. Among all these materials, two-dimensional (2D) compounds with honeycomb-like structure possess exotic electronic structures. Here, we report a systematic study of TMC monolayer AgTe fabricated by direct depositing Te on the surface of Ag(111) and annealing. Few intrinsic defects are observed and studied by scanning tunneling microscopy, indicating that there are two kinds of AgTe domains and they can form gliding twin-boundary. Then, the monolayer AgTe can serve as the template for the following growth of Te film. Meanwhile, some Te atoms are observed in the form of chains on the top of the bottom Te film. Our findings in this work might provide insightful guide for the epitaxial growth of 2D materials for study of novel physical properties and for future quantum devices., 16 pages, 5 figures

Urban traffic is the lifeblood of urban economic activities and plays a very important role in the development of the urban economy and the improvement of people’s living standards. Although the automobile industry brings convenience, it also brings a heavy burden to urban traffic. The imbalance of urban traffic supply and demand has become a serious problem faced by major cities, especially in large cities, the phenomenon of traffic congestion. This not only affects the normal operation of the city, but also reduces the daily work efficiency of people. This paper is based on mature scientific principles and physical devices, such as dynamic Bayesian network, machine vision, machine learning, pattern recognition technology, temperature sensor, optical fiber sensor, etc. The application of artificial intelligence technology in highway traffic is discussed in detail, which lays a theoretical foundation for the development of intelligent traffic in the future.

Butanol fermentation comprises two successive and distinct stages, namely acidogenesis and solventogenesis. The current lack of clarity regarding the underlying metabolic regulation of fermentation impedes improvements in biobutanol production. Here, a proteomics study was performed in the acidogenesis phase, the lowest pH point (transition point), and the solventogenesis phase in the butanol-producing symbiotic system TSH06. Forty-two Clostridium acetobutylicum proteins demonstrated differential expression levels at different stages. The protein level of butanol dehydrogenase increased in the solventogenesis phase, which was in accordance with the trend of butanol concentration. Stress proteins were upregulated either at the transition point or in the solventogenesis phase. The cell division-related protein Maf was upregulated at the transition point. We disrupted the maf gene in C. acetobutylicum TSH1, and Bacillus cereus TSH2 was added to form a new symbiotic system. TSH06△maf produced 13.9 ± 1.0 g/L butanol, which was higher than that of TSH06 (12.3 ± 0.9 g/L). Butanol was furtherly improved in fermentation at variable temperature with neutral red addition for both TSH06 and TSH06△maf. The butanol titer of the maf deletion strain was higher than that of the wild type, although the exact mechanism remains to be determined.

We study the electronic waiting time distributions (WTDs) in a non-interacting quantum dot spin valve by varying spin polarization and the noncollinear angle between the magnetizations of the leads using scattering matrix approach. Since the quantum dot spin valve involves two channels (spin up and down) in both the incoming and outgoing channels, we study three different kinds of WTDs, which are two-channel WTD, spin-resolved single-channel WTD and cross-channel WTD. We analyze the behaviors of WTDs in short times, correlated with the current behaviors for different spin polarizations and noncollinear angles. Cross-channel WTD reflects the correlation between two spin channels and can be used to characterize the spin transfer torque process. We study the influence of the earlier detection on the subsequent detection from the perspective of cross-channel WTD, and define the influence degree quantity as the cumulative absolute difference between cross-channel WTDs and first passage time distributions to quantitatively characterize the spin flip process. The influence degree shows a similar behavior with spin transfer torque and can be a new pathway to characterize spin correlation in spintronics system., Comment: 9 pages, 7 figures

The bismuth-antimony (Bi-Sb) alloys with some specific Sb concentrations are three-dimensional topological insulators (3D TIs). For the thin Bi-Sb alloy films, the quantum confinement effect can suppress the bulk conduction channels and enhance the transport of the topological surface states. However, the fabrication of Bi-Sb films is still challenging. Here, we have successfully prepared the Bi-Sb alloy films by surface Bi-alloying of the epitaxial Sb nanofilm on highly oriented pyrolytic graphite (HOPG) substrate. The morphology, atomic structure, and electronic structure of the Bi-Sb alloy films were characterized by a combination of scanning electron microscopy (SEM), atomic force microscopy (AFM), and scanning tunneling microscopy/spectroscopy (STM/STS). The formation of hexagonal Bi-Sb surface alloy was confirmed by the atomic-resolution STM images. The quantum-well states (QWS) were directly observed in the STS spectra of Bi-Sb films due to the strong quantum confinement effect. The standing-wave patterns of QWS are further observed in the real-space spectra maps. Our work suggests a promising route to fabricate Bi-Sb alloy films and lays the foundation for further exploring their topological electronic structures.

The ultrathin β-Sn(001) films have attracted tremendous attention owing to its topological superconductivity (TSC), which hosts Majorana bound state (MBSs) for quantum computation. Recently, β-Sn(001) thin films have been successfully fabricated via phase transition engineering. However, the understanding of structural phase transition of β-Sn(001) thin films is still elusive. Here, we report the direct growth of ultrathin β-Sn(001) films epitaxially on the highly oriented pyrolytic graphite (HOPG) substrate and the characterization of intricate structural-transition-induced superstructures. The morphology was obtained by using atomic force microscopy (AFM) and low-temperature scanning tunneling microscopy (STM), indicating a structure-related bilayer-by-bilayer growth mode. The ultrathin β-Sn film was made of multiple domains with various superstructures. Both high-symmetric and distorted superstructures were observed in the atomic-resolution STM images of these domains. The formation mechanism of these superstructures was further discussed based on the structural phase transition of β to α-Sn at the atomic-scale thickness. Our work not only brings a deep understanding of the structural phase transition of Sn film at the two-dimensional limit, but also paves a way to investigate their structure-sensitive topological properties.

Turbulent structures generated by vegetation patches play a dominant role in the dispersion of suspended sediment, which in turn is of great significance for ecosystem cycling and river geomorphology development. High fidelity Large Eddy Simulations (LES) coupled with the Discrete Phase Method (DPM) were used to explore the particle distribution and its variance (the non-uniformity in temporal and spatial space) in a partially vegetated straight channel. The novel findings and conclusions are outlined here. Firstly, the contour of the vertical vorticity component coincides well with particle preferential gatherings in the outer edge of the mixing layer in the near-bed region. Large-scale turbulent structures grow in mixing layer along the side of a vegetation patch (VP), which deplete particles away from the mixing layer into the neighbouring region. Also, higher vegetation densities (Dn) promote this depletion trend. Secondly, the Probability Density Function (PDF) and its variance were defined to quantify these phenomena, illustrating that the VP continuously interrupts the flow condition and promotes higher non-uniformity of particle distribution among the vegetated and non-vegetated regions. The variance of the PDF in the non-vegetated region is significantly higher than that in the neighbouring vegetated region located in the same streamwise location. The particle parcels are highly unevenly located along the periphery of the large eddies and are exchanged by the mixing flow between the non-vegetated and vegetated regions. Finally, the vertical entrainment of particles occurs in the vegetated region of the present cases. This is because the horseshoe structures provide an upwards velocity for the current Dn conditions (Dn

In the present paper, the authors investigated the adsorption of cadmium on magnetic Levextrel resin containing about 352 mg g−1 Cyanex 272 (C272) as adsorbent. Magnetic Levextrel resin (mPst-DVB-C272) was synthesized through adding Cyanex 272 and oleic acid-coated magnetite nanoparticles directly to the mixture of styrene (st) and divinylbenzene (DVB) monomers during the bead polymerization. It is a new method for preparing magnetic Levextrel resins with less organic solvents and less steps MPst-DVB-C272 was characterized with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravity (TG) and differential thermal gravity (DTG), and vibrating sample magnetometry (VSM). Then mPst-DVB-C272 was applied to remove cadmium. The effects of pH, initial Cd(II) concentration, and contact time on Cd(II) removal were investigated in batch experiments. The optimized pH value for the Cd(II) adsorption was 6.5. The maximum adsorption capacity was 18.77 mg g−1 for mPst-DVB-C272. The adsorption reached equilibrium within 90 min and the experimental data fit the pseudo-second-order model.

The highly viscous liquid (glycerin) sloshing is investigated numerically in this study. The full-scale membrane-type tank is considered. The numerical investigation is performed by applying a two-phase numerical model based on the spatially averaged Navier-Stokes equations. Firstly, the numerical model is validated against the available numerical model and a self-conducted experiment then is applied to systematically investigate the full-scale sloshing. In this study, two filling levels (50% and 70% of the tank height) are considered. The fluid kinematic viscosity is fixed at a value being 6.0 × 10−5 m2/s with comparative value to that of the crude oil. A wide range of forcing periods varying from 8.0 s to 12.0 s are used to identify the response process of pressures as well as free surface displacements. The pressures are analyzed along with breaking free surface snapshots and corresponding pressure distributions. The slamming effects are also demonstrated. Finally, the frequency response is further identified by the fast Fourier transformation technology.

Natural Language Processing is an important direction in the fields of computer science and artificial intelligence. It has a wide range of applications, such as text classification, machine translation, emotional analysis, etc. where text classification is typically characterized of capturing the language features of e-mails to identify the authors. In this paper, mathematic models are set up and compared based on the traditional text classification method and the Deep Learning text classification method respectively. Finally, the following results are obtained: The accuracy of the model using the improved network architecture based on TextCNN reaches 87% on the training set and 88.97% on the test set. The accuracy of using the improved network architecture based on CLSTM reaches 90% on the training set and 88.34% on the test set. The accuracy of the new network architecture based on recurrent neural network (RNN) and convolutional neural network (CNN) has reached 92.32% on the training set and 92.80% on the test set. Using integrated learning to integrate the model, the accuracy rate is 94% on the training set and 92.36% on the test. The model based on SVM are tested with the test set to get the accuracy rate 60.44%.

The viscous effects on the horizontally-excited sloshing under resonant and off-resonant excitations are investigated experimentally. Both tap water and glycerin at different temperatures are chosen as the experimental fluids. The intermediate depth ratio h/L = 0.2 is chosen. The sloshing of water and glycerin at four kinematic viscosities ranging from 1.14 × 10−6 m2/s to 1.1 × 10−3 m2/s is studied. Through well-controlled experiments, by analyzing the pressure and free surface snapshot, the sloshing gradually turns from the resonant-steady state to the harmonic state for a certain viscosity threshold. The free surface profiles of low and high viscous fluids under resonant excitations are further analyzed, in connection with the dynamic pressures and excitation accelerations. The peak dynamic pressures are successively out of synchrony with the peak excitation accelerations, obvious phase shift occurs which eventually goes to one fifth of the resonant frequency. Through the fast Fourier transform, it is found that the dominant response frequencies of high viscous fluids are integral times of the forcing frequency behaving a distinct state from the low viscous fluids especially for the water.

Fractal dimension is an appropriate indicator to describe the complexity of a certain geometry, and box-counting analysis is proved to be an effective and appropriate method for fractal dimension estimation which is widely used. However, traditional box-counting methods based on images may not always accurate especially in small box scale due to the restriction of pixels. This paper aims to introduce a method based on generating fractal and determining boxes by rigid mathematical definition to eliminate the deviation of each box scale and to carry out more dependable results. Several samples of the simple and recursive fractal are analyzed to verify the accuracy of the box-counting method based on mathematical definition and interval in this paper. Keywords: Fractal, Fractal dimension, Box-counting method

We investigate the waiting time distributions (WTDs) of superconducting hybrid junctions, considering both conventional and topologically nontrivial superconductors hosting Majorana bound states at their edges. To this end, we employ a scattering matrix formalism that allows us to evaluate the waiting times between the transmissions and reflections of electrons or holes. Specifically, we analyze normal-metal-superconductor (NIS) junctions and NISIN junctions, where Cooper pairs are spatially split into different leads. The distribution of waiting times is sensitive to the simultaneous reflection of electrons and holes, which is enhanced by the zero-energy state in topological superconductors. For the NISIN junctions, the WTDs of trivial superconductors feature a sharp dependence on the applied voltage, while for topological ones they are mostly independent of it. This particular voltage dependence is again connected to the presence of topological edge states, showing that WTDs are a promising tool for identifying topological superconductivity., 11 pages, 3 figures

It is important to develop full-performance bio-jet fuel based on alternative feedstocks. The compound 1-butanol can be transformed into jet fuel through dehydration, oligomerization, and hydrogenation. In this study, a new catalyst consisting of Zn-Mn-Co modified γ-Al2O3 was used for the dehydration of high-concentration 1-butanol to butenes. The interactive effects of reaction temperature and butanol weight-hourly space velocity (WHSV) on butene yield were investigated with response surface methodology (RSM). Butene yield was enhanced when the temperature increased from 350 °C to 450 °C but it was reduced as WHSV increased from 1 h−1 to 4 h−1. Under the optimized conditions of 1.67 h−1 WHSV and 375 °C reaction temperature, the selectivity of butenes achieved 90%, and the conversion rate of 1-butanol reached 100%, which were 10% and 6% higher, respectively, than when using unmodified γ-Al2O3. The Zn-Mn-Co modified γ-Al2O3 exhibited high stability and a long lifetime of 180 h, while the unmodified γ-Al2O3 began to deactivate after 60 h. Characterization with X-ray diffraction (XRD), nitrogen adsorption-desorption, pyridine temperature-programmed desorption (Py-TPD), pyridine adsorption IR spectra, and inductively coupled plasma atomic emission spectrometry (ICP-AES), showed that the crystallinity and acid content of γ-Al2O3 were obviously enhanced by the modification with Zn-Mn-Co, and the loading amounts of zinc, manganese, and cobalt were 0.54%, 0.44%, and 0.23%, respectively. This study provides a new catalyst, and the results will be helpful for the further optimization of bio-jet fuel production with a high concentration of 1-butanol.

The quasi-bound states of a superconducting quantum dot that is weakly coupled to a normal metal appear as resonances in the Andreev reflection probability, measured via the differential conductance. We study the evolution of these Andreev resonances when an external parameter (such as magnetic field or gate voltage) is varied, using a random-matrix model for the $N\times N$ scattering matrix. We contrast the two ensembles with broken time-reversal symmetry, in the presence or absence of spin-rotation symmetry (class C or D). The poles of the scattering matrix in the complex plane, encoding the center and width of the resonance, are repelled from the imaginary axis in class C. In class D, in contrast, a number $\propto\sqrt{N}$ of the poles has zero real part. The corresponding Andreev resonances are pinned to the middle of the gap and produce a zero-bias conductance peak that does not split over a range of parameter values (Y-shaped profile), unlike the usual conductance peaks that merge and then immediately split (X-shaped profile)., Contribution for the JETP special issue in honor of A.F. Andreev's 75th birthday. 9 pages, 8 figures

We calculate the conductance of a two-dimensional bilayer with inverted electron-hole bands, to study the sensitivity of the quantum spin Hall insulator (with helical edge conduction) to the combination of electrostatic disorder and a perpendicular magnetic field. The characteristic breakdown field for helical edge conduction splits into two fields with increasing disorder, a field $B_{c}$ for the transition into a quantum Hall insulator (supporting chiral edge conduction) and a smaller field $B'_{c}$ for the transition to bulk conduction in a quasi-metallic regime. The spatial separation of the inverted bands, typical for broken-gap InAs/GaSb quantum wells, is essential for the magnetic-field induced bulk conduction --- there is no such regime in HgTe quantum wells., 4 pages, 6 figures; Corrected a factor of two error in the magnetic field scale and effective g-factor

We show how the superconducting phase difference in a Josephson junction may be used to split the Kramers degeneracy of its energy levels and to remove all the properties associated with time reversal symmetry. The superconducting phase difference is known to be ineffective in two-terminal short Josephson junctions, where irrespective of the junction structure the induced Kramers degeneracy splitting is suppressed and the ground state fermion parity must stay even, so that a protected zero-energy Andreev level crossing may never appear. Our main result is that these limitations can be completely avoided by using multi-terminal Josephson junctions. There the Kramers degeneracy breaking becomes comparable to the superconducting gap, and applying phase differences may cause the change of the ground state fermion parity from even to odd. We prove that the necessary condition for the appearance of a fermion parity switch is the presence of a "discrete vortex" in the junction: the situation when the phases of the superconducting leads wind by $2\pi$. Our approach offers new strategies for creation of Majorana bound states as well as spin manipulation. Our proposal can be implemented using any low density, high spin-orbit material such as InAs quantum wells, and can be detected using standard tools., Comment: Source code available as ancillary files. 10 pages, 7 figures. v2: minor changes, published version

The phase-dependent bound states (Andreev levels) of a Josephson junction can cross at the Fermi level, if the superconducting ground state switches between even and odd fermion parity. The level crossing is topologically protected, in the absence of time-reversal and spin-rotation symmetry, irrespective of whether the superconductor itself is topologically trivial or not. We develop a statistical theory of these topological transitions in an N-mode quantum-dot Josephson junction, by associating the Andreev level crossings with the real eigenvalues of a random non-Hermitian matrix. The number of topological transitions in a 2pi phase interval scales as sqrt(N) and their spacing distribution is a hybrid of the Wigner and Poisson distributions of random-matrix theory., Comment: 12 pages, 15 figures; v2 to appear in PRL, with appendix in the supplementary material

We show how a quantum dot with a ballistic single-channel point contact to a superconductor can be created by means of a gate electrode at the edge of a quantum spin Hall insulator (such as an InAs/GaSb quantum well). A weak perpendicular magnetic field traps a Majorana zero-mode, so that it can be observed in the gate-voltage-averaged differential conductance as a 4e^2/h zero-bias peak above a (2/3{\pi}^2 - 4)e^2/h background. The one-dimensional edge does not permit the braiding of pairs of Majorana fermions, but this obstacle can be overcome by coupling opposite edges at a constriction, allowing for a demonstration of non-Abelian statistics., Comment: 6 pages, 4 figures

We calculated the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between the magnetic impurities mediated by electrons in nanoribbons. It was shown that the RKKY interaction is strongly dependent on the width of the nanoribbon and the transverse positions of the impurities. The transverse confinement of electrons is responsible for the above size effect of the RKKY interaction. It provides a potential way to control the RKKY interaction by changing nanostructure geometry.