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False data injection (FDI) attacks are common in the distributed estimation of multi-task network environments, so an attack detection strategy is designed by combining the generalized maximum correntropy criterion for the above problem. Based on this, a diffusion least-mean squares algorithm based on the generalized maximum correntropy criterion (GMCC-DLMS) for multi-task networks is proposed. The algorithm achieves gratifying estimation results. Even more, compared to the related work, it has better robustness when the number of attacked nodes increases. Besides, the assumption about the number of attacked nodes is relaxed, which is applicable to multi-task environments. In addition, the performance of the proposed GMCC-DLMS algorithm is analyzed in the mean and mean-square senses. Finally, simulation experiments confirm the performance and effectiveness against FDI attacks of the algorithm.

To realize precise and stable power grid dispatching, it is urgent to realize the combined scheduling of Pumped Storage and Thermal Power (PSTP). Considering some factors in the power system, a multi-objective combined optimization model of PSTP is proposed in this paper. Then, this paper proposes an improved multi-objective optimization algorithm base on deep reinforcement learning to solve the above model. Finally, this paper analyzes the advantages and disadvantages of the proposed multi-objective optimization model and finds that the model proposed in this paper sacrifices certain economic benefits but can reduce the system’s fluctuation and improve the power system’s reliability.

The β-Ga2O3 films with different thicknesses are prepared by an atomic layer deposition system. The influence of film thickness on the crystal quality is obvious, indicating that the thicker films perform better crystal quality, which is verified from x-ray diffraction (XRD) and scanning electron microscope (SEM) results. The Ga2O3-based solar blind photodetectors with different thicknesses are fabricated and studied. The experimental results show that the responsivity of the photodetectors increases exponentially with the increase of the film thickness. The photodetectors with inter-fingered structure based on 900 growth cycles β-Ga2O3 active layers (corresponding film thickness of 58 nm) exhibit the best performances including a low dark current of 134 fA, photo-to-dark current ratio of 1.5 × 107, photoresponsivity of 1.56 A/W, detectivity of 2.77 × 1014 Jones, and external quantum efficiency of 764.49% at a bias voltage of 10 V under 254-nm DUV illumination. The photoresponse rejection ratio (R 254/R 365) is up to 1.86 × 105. In addition, we find that the photoelectric characteristics also depend on the finger spacing of the MSM structure. As the finger spacing decreases from 50 μm to 10 μm, the photoresponsivity, detectivity, and external quantum efficiency increase significantly.

Compared with traditional orthopedic surgical instruments, the ultrasonic bone scalpel (UBS) has obvious advantages in both safety and effectiveness. Based on the structure of the sandwich piezoelectric transducer, a design of half-wavelength UBS with a longitudinal vibration frequency of 22.5 kHz is proposed in this study. Firstly, the dimensions of each component of the UBS are calculated by the transmission matrix method, the initial design is verified by modal analysis, and the error is optimized by the response surface method. Then the harmonic response analysis is used to calculate the UBS’s tip amplitude, impedance and stress distribution. In addition, the influence of bolt pre-tightening force on the vibration characteristics of the UBS is analyzed. When the bolt pre-tightening force is 50-90MPa, the vibration performance of the UBS is stable, and the tip amplitude is large, which provides a reference for selecting appropriate tightening torque when the UBS is assembled. Finally, the bone-cutting experiment shows that the UBS has good cutting performance.

Based on two-mode continuous Hadamard gate (TCHG) and multi-photon catalysis, this paper presents a scheme to generate non-classical quantum states via coherent state. When considering the m-photon input and m-photon detection in a-mode, the output state is obtained for the input coherent in b-mode. An interesting finding is that as the amplitude of the output coherent state increases, both the detection efficiency and the fidelity of the output quantum state gradually approach zero. Thus, only certain low-intensity quantum light field states can pass through Hadamard gate. In addition, the quantum statistical distribution and squeezing properties of the output quantum states are also analyzed in detail. Our results show that TCHG is a powerful tool for generating non-classical quantum states under multi-photon catalysis.

This paper proposes a class of high-performance surface acoustic wave (SAW) waveguides based on AlN-on-SiC substrates. Under the existing crystal growth and processing technology, these SAW waveguides offer excellent performance in single mode, low loss, ultra-broadband, operating at gigahertz frequencies. Quasi-Rayleigh SAWs can be excited by traditional interdigital transducers and guided freely with excellent efficiency. Based on these SAW waveguides, we further demonstrate SAW splitters and ring cavities with ultra-high qualities up to 107. These SAW components complement future integrated phononic circuits for high-frequency and compact acoustic manipulating, signal processing, sensing, computing, etc.

Herein, the interaction and relative motion of two circular magnetic particles in a static flow and planar Poiseuille flow is investigated via numerical simulation. A two-dimensional numerical model is constructed based on Maxwell’s finite element method, fully considering the interactions between particles and particles, particles and magnetic fields, and particles and flow fields. First, the motion state and action mechanism of the magnetic particles in contact state in the static fluid are analyzed under a vertical magnetic field; then, the simulation results are verified via experiments. Based on the motion state of the magnetic particles in the planar Poiseuille flow, the feasibility of effectively controlling the trajectory of magnetic particles in the planar Poiseuille flow using a magnetic field is discussed. In the static flow, the vertical magnetic field was unable to separate the contacting magnetic particles; thus, the magnetic field cannot effectively control magnetic particles in static flows. In the planar Poiseuille flow, the free contact and separation of magnetic particles was effectively controlled by the combined action of the magnetic field and the fluid. This study provides insights into the interactions among magnetic particles in static flows and summarizes a set of methods for effectively controlling two circular magnetic particles.

We report the experimental generalized oscillator strengths (GOSs) for transitions from the ground state X ~ A 1 ′ 1 to the Rydberg states B ~ E ′ ′ 1 , C ~ ′ A 1 ′ 1 , D ~ E ′ 1 + D ~ ″ A 2 ′ ′ 1 , E ~ E ′ 1 ( v 2 ′ = 0 – 7 ) + ( F ~ E ′ 1 + G ~ A 2 ′ ′ 1 ) ( v 2 ′ = 0 – 4 ) and an ‘undefined’ state U ~ ( v 2 ′ = 0 – 4 ) in ammonia. The experiment was performed using an angle-resolved electron energy loss spectrometer operated at an incident energy of 1500 eV and an energy resolution of about 80 meV. The experimental observation confirms the recent theoretically predicted appreciable vibrational effects on the GOS for the transition B ~ E ′ ′ 1 ← X ~ A 1 ′ 1 (2021 J. Phys. B: At. Mol. Opt. Phys. 54 135202). The measured GOS data are fitted with the Lassettre formula to determine the corresponding optical oscillator strengths for dipole-allowed transitions. Furthermore, the fitted curves enable the integrations of GOSs over the momentum transfer squares to obtain the Born excitation cross sections. The integral cross sections are scaled to an accurate scale by using the BE-scaling method. The data in this work can supplement the molecular database and deepen our understanding of the scattering mechanism.

An analytical method for the spherical stress wave equation in linear hardening materials under impact loading is given in this paper. In this method, the elastic, unloading and plastically loading wave equations are solved, separately. In the elastic region, the solutions under different wave velocity ratio conditions are given. In the unloading region and the plastically loading region, the general solutions of the equations are given and the ordinary differential equations of the arbitrary functions are obtained. And then the exact solutions of the equations are given. The stress contour diagrams in the medium under typical loading conditions are given by the analytical method. The correctness of the analytical method is verified by comparing with the numerical results. On the stress contour diagrams, the discontinuities of the analytical results are clearer than that of the numerical results. A parametric study is conducted to show the effects of the parameters on the behaviour of stress distributions. This method can be useful for the rapid calculation of the elastic-plastic spherical stress waves in engineering and the theoretical analysing and law studying of the elastic-plastic spherical stress wave researches.

The magnetic properties of single crystals Si, SrTiO3, LaAlO3, MgO, and (La,Sr)(Al,Ta)O3 were investigated systematically. Three origins of the magnetizations of these crystals, namely, an intrinsic diamagnetic, a paramagnetic, and a ferromagnetic contribution, have been found to influence the magnetic signals measured on the crystals, in some important application scenarios such crystals being served as substrates with the magnetic thin film epitaxially grown on. Quantitative analyses methodologies were developed and thorough investigations were performed on the crystals with the intrinsic materials parameters thus revealed, especially that the intrinsic diamagnetic susceptibility differential dχ dia/dT were identified quantitatively for the first time in SrTiO3, LaAlO3, MgO, and (La,Sr)(Al,Ta)O3. The paramagnetic contribution is found to be the key in terms of the magnetic properties of the crystals, which in turn is in fact a consequence of the 3d impurities doping inside the crystal. All the intrinsic materials parameters are given in this paper as datasets, the datasets are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00028.

The property of concrete is very significant to structural safety, and the early hydration process plays a critical role in the final concrete property. This paper develops a self-emission and detection (SED) principle with a single piezoelectric smart aggregate (SA) transducer, which is used as both an actuator and a sensor, to monitor the concrete early age strength development. The signal analysis is carried out by the coda wave energy (CWE). Experiments of concrete specimens with and without the SAs were conducted. Experimental results show a high correlation between the strength of early-age concrete and the CWE and non-linear fitting is used to establish the relationship between them. The proposed CWE features a simple analysis method, and the SED principle does not require consideration of the matching between the transmitting transducer and the receiving sensor, such as frequency range, sensitivity. Furthermore, the proposed method can be used as a reference for health monitoring of other structures and has good application prospects.

Nonlinear optical waveguides play a crucial role in the wavelength/frequency conversion of light. Femtosecond laser direct writing is an efficient and flexible technique to produce waveguides in dielectrics. We report on the nonlinear waveguides in LiB3O5 crystals by femtosecond laser writing. The double-line and depressed-cladding structures inscribed by femtosecond laser pulses show excellent guiding properties at 405 nm or 810 nm for both TE and TM polarized light. The investigations of the confocal micro-Raman spectroscopy have indicated that lattice structures in waveguide cores remain almost unchanged compared with those of the bulk. Based on type-I phase matching condition, both second harmonic generation of 810 nm and spontaneous parametric down conversion of 405 nm have been obtained in the laser-written lithium triborate waveguides, suggesting potential applications in integrated nonlinear optics and quantum photonics.

We demonstrate an optical frequency comb (OFC) based on a turnkey mode-locked laser with a figure-9-shape structure and polarization-maintaining fibers, for the comparison of frequency among optical clocks with wavelengths of 698 nm, 729 nm, 1068 nm, and 1156 nm. We adopt a multi-branch approach in order to produce high power OFC signals at these specific wavelengths, enabling the signal-to-noise ratio of the beatnotes between the OFC and the clock lasers to exceed 30 dB at a resolution bandwidth of 300 kHz. This approach makes the supercontinuum spectra much easier to be generated than a single branch OFC. However, more out-of-loop fibers degrade the long-term frequency instability due to thermal drift. To minimize the thermal drift effect, we set the fiber lengths of different branches to be similar, and we stabilize the temperature as well. The out-of-loop frequency instability of the OFC due to the incoherence of the multi-branch is about 5.5 × 10−19 for 4000 s, while the in-loop frequency instability of f ceo and that of f beat are 7.5 × 10−18 for 1 s and 8.5 × 10−18 for 1 s, respectively. The turnkey OFC meets the requirement for the comparison of frequency between the best optical clocks.

In order to solve the problems of poor versatility and high clamping damage rate faced by the end-effector of picking robots in today’s picking operation, a universal spherical fruit and vegetable picking die end-effector based on vision recognition with adaptive flexible force clamping is designed. This end-effector is a pneumatic three structure, while integrating a small air source device, in the control of a variety of sensors, through the fusion of multiple sensing and algorithm improvement and other ways, so that the mold end-effector in the picking operation, through visual recognition to determine the type of fruit and vegetables, and then provide the optimal gripping force. At the same time, the fingertip is equipped with a pressure sensor to adjust the pressure output in real time to achieve the overall picking process, the pressure is kept constant, and in the judgment of the completion of fruit and vegetable picking, a torque sensor is equipped to presume the completion of the picking operation by twisting the fruit strength. Finally, the actual product was made and several fruit and vegetable simulation experiments were carried out. The experimental structure is good, which verifies that the end-effector has good versatility and flexibility.

Vibration-based damage detection using the 2D modal curvature has become a research focus. However, the traditional methods based on modal curvature lack the sensitivity to direction of the damage. To address this problem, a directional 2D Morlet wavelet modal curvature is proposed in this paper. The directional wavelet modal curvatures show the following merits: robust to noise interference and sensitive to direction of damage. By the numerical simulation, the efficiency of the proposed method is demonstrated in the plate-like structure.

Ternary transition metal chalcogenides provide a rich platform to search and study intriguing electronic properties. Using angle-resolved photoemission spectroscopy and ab initio calculation, we investigate the electronic structure of Cu2TlX 2 (X = Se, Te), ternary transition metal chalcogenides with quasi-two-dimensional crystal structure. The band dispersions near the Fermi level are mainly contributed by the Te/Se p orbitals. According to our ab-initio calculation, the electronic structure changes from a semiconductor with indirect band gap in Cu2TlSe2 to a semimetal in Cu2TlTe2, suggesting a band-gap tunability with the composition of Se and Te. By comparing ARPES experimental data with the calculated results, we identify strong modulation of the band structure by spin–orbit coupling in the compounds. Our results provide a ternary platform to study and engineer the electronic properties of transition metal chalcogenides related to large spin–orbit coupling.

A quantum entangled state is easily disturbed by noise and degenerates into a separable state. Compared to the entanglement with bipartite quantum systems, less progress has been made for the entanglement with multipartite quantum systems. For tripartite separability of a four-qubit system, we propose two entanglement witnesses, each of which corresponds to a necessary condition of tripartite separability. For the four-qubit GHZ state mixed with a W state and white noise, we prove that the necessary conditions of tripartite separability are also sufficient at W states side.

To ensure the safety of water quality, pipe network cleaning and security management are put forward higher requirements. Traditional single-phase water flushing pipe technology requires high velocity and large flow rate of water, which does not suitable for large-diameter pipes. Air and water flushing pipes are new pipeline cleaning technology, which has high efficiency, good washing effect, and can save a lot of water. The principles of airwater flushing large-diameter, large-deviation-elevation, and many- ups-and-downs pipes are described in this paper. Based on the two-phase flow theories, it analyzes complex hydraulic characteristics and control parameters for flushing pipeline. Combine with engineering practice, air and water flushing diameter of 800 mm pipeline in Shanghai city and flushing pipe parameters are introduced. The air and water flushing effect and water resource consumption reduction are analyzed, as well.

The reasonable scale of urban river ecological space and the connectivity of bank and slope water and soil exchange are the basic conditions to keep the flow of matter, energy and species in water unimpeded, as well as the way out for the dilemma of urban river ecological governance. The concept of resilience in spatial planning is used to break the artificial partition between river land space and water space, explore the compound function of urban space, and realize the way of integration and synergism of land and water space.The research shows that scientific overall planning and rational utilization of urban space is the basis of realizing land function combination and solving urban river governance predicament. Urban spatial planning and layout should highlight the backbone role of river-dominated urban eco-environment texture, restore the function of river network ecological corridor, build the integration of public open space and river space, optimize the use of land resources for achieving functional compounding; Meanwhile, expand the three-dimensional space of the river, increase the spatial diversity, improve the openness of the waterfront space for achieving functional balance through collaboration. To break the artificial boundaries of waters and land areas and form the integration of land and water area, the water environment management of river spatial design needs to focus on key elements such as the urban river network plane shape, the spatial layout of river sections, the ecological treatment and reconstruction of bank protection, and the temporal and spatial evolution of rivers. Application of multi-natural river ecological restoration, near-natural river construction, semi-natural ecological flood control and other technologies can achieve the ecological treatment effect of bank protection and improve the ecological permeability of bank slope. By opening up the river space, it provides a limited dynamic change space for the river bed and a space that evolves with time, which is conducive to exerting the function of ecological corridor of urban river system and driving the improvement and promotion of ecological environment in urban areas.

Underwater transportation of bubbles and gases has essential applications in manipulating and using gas, but achieving this function at the microscopic level remains a significant challenge. Here, we report a strategy to self-transport gas in water along a laser-induced open superhydrophobic microchannel with a width less than 100 µm. The femtosecond laser can directly write superhydrophobic and underwater superaerophilic microgrooves on the polytetrafluoroethylene (PTFE) surfaces. In water, the single laser-induced microgroove and water medium generate a hollow microchannel. When the microchannel connects two superhydrophobic regions in water, the gas spontaneously travels from the small region to the large area along this hollow microchannel. Gas self-transportation can be extended to laser-drilled microholes through a thin PTFE sheet, which can even achieve anti-buoyancy unidirectional penetration. The gas can overcome the bubble’s buoyance and spontaneously travel downward. The Laplace pressure difference drives the processes of spontaneous gas transportation and unidirectional bubble passage. We believe the property of gas self-transportation in the femtosecond laser-structured open superhydrophobic and underwater superaerophilic microgrooves/microholes has significant potential applications related to manipulating underwater gas.

In Lamb wave-based structural health monitoring, amplitude damage imaging is commonly used because the defects feature can be easily amplified by summing all the response signals together. However, the grating and side lobes affect the imaging quality and blind areas further restrict the inspection area. Considering that the existing phase-based imaging algorithms are either unfit for dispersive Lamb wave or strict to many requirements to guarantee better performance, inspired by the absence of phase information in focusing phased array, a novel focusing phase imaging (FPI) method for Lamb wave phased array is developed. The main contribution of the paper is introducing the phase information to focusing phased array. By applying the inverse-dispersion effect to the excitation signals and the superposition operation, the energy can be focused at every inspection point. The phase damage index is constructed by directly measuring the degree of consistency and alignment of the instantaneous phases. The experiments for the circular and linear array under various excitation signals with multiple defects verify that the FPI is effective for both surface damage and through-hole damage. The proposed algorithm is superior for its ability in energy focusing for defects, the capability in suppression of grating and side lobes, strong anti-disturbance ability from boundary reflection, the nonexistence of imaging blind area, and its adaptability for various excitation parameters and array layout.

Breast Cancer (BC) is the most common malignant tumor for women in the world. Histopathological examination serves as basis for breast cancer diagnosis. Due to the low accuracy of histopathological images through manual judgment, the classification of histopathological images of breast cancer has become a research hotspot in the field of medical image processing. Accurate classification of images can help doctors to properly diagnoses and improve the survival rate of patients. This paper reviews the existing works on histopathological image classification of breast cancer and analysis the advantages and disadvantages of related algorithms. Findings of the histopathological image classification of the Breast Cancer study are drawn, and the possible future directions are also discussed.

Under the action of an external magnetic field, the magnetic particles will be arranged along the direction of the magnetic field. The laws of physics that control these processes are well described in the literature. However, when the magnetic particles move in the fluid, the magnetic particles with different initial distances have different mutual influences, so there will be different laws of motion. Therefore, based on the motion theory of magnetic particles in Stokes fluid, this article discusses the motion law of the contact and separation of two circular magnetic particles in Newtonian fluid. First, we conduct theoretical and simulation modeling of two magnetic particles under the action of a uniform magnetic field, and verify the correctness of the simulation through experiments; secondly, we use numerical simulation to study the angle of repulsion and attraction of magnetic particles at different initial distances, and analyze at the same time the changes in the trajectory, speed, torque and force of magnetic particles in the process of motion are studied. Finally, the influence of external field conditions on the phenomenon of contact and separation of magnetic particles is studied. The study found that even when the initial angle between the magnetic particles is 90° with the direction of the magnetic field, the magnetic particles with different initial distances will repel under the action of repulsive force and then contact again and keep repelling these two states, a better explanation the reason for the agglomeration of magnetic particles at close range is explained.

The notion of non-Hermitian optics and photonics rooted in quantum mechanics and photonic systems has recently attracted considerable attention ushering in tremendous progress on theoretical foundations and photonic applications, benefiting from the flexibility of photonic platforms. In this review, we first introduce the non-Hermitian topological physics from the symmetry of matrices and complex energy spectra to the characteristics of Jordan normal forms, exceptional points, biorthogonal eigenvectors, Bloch/non-Bloch band theories, topological invariants and topological classifications. We further review diverse non-Hermitian system branches ranging from classical optics, quantum photonics to disordered systems, nonlinear dynamics and optomechanics according to various physical equivalences and experimental implementations. In particular, we include cold atoms in optical lattices in quantum photonics due to their operability at quantum regimes. Finally, we summarize recent progress and limitations in this emerging field, giving an outlook on possible future research directions in theoretical frameworks and engineering aspects.