Abstract:This paper discusses the existence and uniqueness of solutions for the boundary value problem of a class of nonlinear second-order ordinary differential system. By using the Leray-Schauder fixed point theorem, the existence and uniqueness of solutions is obtained.

Abstract:We investigate the dynamical behavior of lattice FitzHugh-Nagumo equation with fast-varying delays and obtain the existence and uniqueness of pullback attractor for the equation. Generally, studying the attractors of a time-varying delay equation require that the derivative of the delay term is less than 1 ( slow-varying delay). However, in this paper, by using some differential inequality techniques we remove this constraint. Therefore, our method can be used to deal with the equations with fast-varying delays.

Abstract:We propose three Grad-Div stabilized Taylor-Hood finite elements for the steady Navier-Stokes equation. To keep the law of mass conservation, the Grad-Div stabilized term is added to the known discrete solutions obtained with Taylor-Hood elements, so as to get continuous velocity and pressure, and velocity solutions obeying the law of mass conservation. Under the strong uniqueness conditions, we also show that the Grad-Div stabilized Taylor-Hood finite element iterative solutions converge to the Scott-Vogelius solutions. Finally, numerical examples verify the efficiency of the finifte elements.

Abstract:In this study, we combine the semantic segmentation technology based on full convolution neural network and image segmentation technology based on level set method and use Deeplab V2 and Distance Regularized Level Set Evolution (DRLSE) model to realize general color images segmentation. To improve the evolution speed of the zero level set segmentation, a new shape energy term is added to the DRLSE model. Numerical simulations verify the efficiency of our method.

Abstract:We investigate the crossing periodic orbits of a piecewise linear Lienard-like system with symmetric admissible foci. By reducing the system to a normal form with less parameters and constructing the Poincare maps for the left and right subsystems, we show the existence of at least one crossing periodic orbit, give a sufficient condition for the non-existence of crossing periodic orbits, and provide an upper bound for the number of crossing periodic orbits under some conditions.

Abstract:Remote sensing image denoising plays a very important role in the subsequent classification and detection tasks for remote sensing images. In order to retain more the edge details information in the denoised images and enhance the discrimination for contaminated regions, in this paper, the authors propose a new Attention based Residual Encoder-Decoder network aided by VGG (ARED-VGG) for remote sensing image denoising, which combines attention mechanism, and perceptual loss. First, considering that the different ground objects have different sizes, the network utilizes both spatial and spectral information to extract multiscale features. Second, in order to better represent the extracted features and improve the denoising effect, the residual autoencoder network is used in image reconstruction stage. Moreover, convolution operations that are responsible to extract high-frequency features should be paid more attention to facilitating the location of noise-affected regions. Based on these considerations, the attention mechanism is introduced to adaptively modulate feature representation. Finally, perceptual loss is adopted to maintain the visual results consistent to the human perception. In the experiments, the proposed method demonstrates superior performance in noise suppression and detail preservation to NLM3D, BM4D, LRMR, HSID-CNN and 3DADCNN. Simulation experiments were carried out on the Washington DC mall remote sensing image data set, d the results of mean peak signal-to-noise ratio and mean structure similarity index of the proposed method are better than the other methods. Real experiments were carried out on the AVIRIS Indian pines data set. The classification results for the denoised images were evaluated. The overall classification accuracy and kappa coefficient were 96.90% and 0.9647, respectively. The ablation experiment was carried out on the network structure on both data sets the proposed network architecture achieved best results. This paper proposes a deep neural network based on attention mechanism and perceptual loss to denoise remote sensing images, which improves the recognition ability of the network, achieves good denoising performance, and effectively preserves the detailed information and spectral information of the image.

Abstract:Extracting the relation of the property involved from laws and regulations to build a knowledge base is of great significance to the intelligent management of the property involved in the judicial practice. However, in this scenario, the training corpus is small and single, while high extraction accuracy required, so the relation extraction method of machine learning is not applicable. Aiming at addressing this problem, we propose a new relation extraction approach that extracts relations by template matching with fuzzy logic mechanism. In this approach, in order to cater to the actual needs of the knowledge base for property involved, two attributes are added to the traditional threetuple relation to obtain the five-tuple relation model. Three extraction templates were designed from different dimensions, and the extraction results were judged with the help of fuzzy logic to compete for a better five-tuple relation, which provided support for the construction of the knowledge base for property involved.

Abstract:When using Autonomous Mobile Robot (AMR) cluster to process airport baggage intelligently and efficiently, in order to solve the allocation and scheduling problem of AMR cluster in the airport environment, a task scheduling strategy with an improved greedy algorithm is proposed. According to the random baggage quantity, the appropriate AMR quantity is allocated to perform the processing task. The proposed algorithm comprehensively considers the arrival rules and AMR characteristics of baggage tasks in an airport environment, and accordingly improves the greedy selection strategy, which making it better than other algorithms to reflect the scheduling and allocation relationship between baggage tasks and AMR. Firstly, the A* algorithm is used to calculate the cost, which can obtain a substitute value that is more in line with the actual environment. Secondly, the type division of AMR and the use of advance departure strategies reduce the task allocation time and system runtime. Simulation results show that the algorithm can obtain at least 8.9% improvement in system runtime compared with the greedy algorithm.

Abstract:Password identification is one of the most popular way of identification. Generating a large-scale password set based on password-generation techniques is a principal method to research password security, which can be applied to evaluate the efficiency of password-generation algorithm and detect the defects of existing user-password protective mechanisms. In this paper, we propose a password-generation model based on an ordered Markov enumerator and critical neural network (OMECNN). The OMECNN model combines both Markov chain and neural network techniques. OMECNN utilizes the ordered Markov passwords enumerator to generate the passwords according to the probability of combinations, and then uses the critic neural network to score those passwords, and selects the passwords whose score is higher than the threshold to form the final password set. The generated password set has the characteristics of sorting according to the combination probability of passwords and the distribution of passwords in accordance with the real training password set. The experimental results show that when 1e7 passwords are generated, the hits of OMECNN model on Rockyou test set is 16.60% higher than that of OMEN model and 220.02% higher than that of Pass GAN model.

Abstract:Data set matrix is missing in data analysis, data elements can be completed by data matrix, and the efficient completion data matrix algorithm can be optimized and improved from the aspects of algorithm accuracy. A Symmetric Weighting (SW) algorithm is proposed. Firstly, according to the general matrix completion model, the regularization method is used to complete the low-rank matrix decomposition. Secondly, a new matrix completion model and a regularization weighting function are obtained by weighting the decomposed matrix factors with a common symmetric matrix. Finally, using block coordinate descent and alternate least square optimization algorithm, the optimal solution of the objective function is obtained iteratively, and the optimal completion matrix of data completion is obtained. Compared with APALM, IRSVF and IRNN, the symmetric weighting algorithm has better improvement in the precision and convergence speed of data matrix completion.

Abstract:Research shows that the role of body posture in emotion recognition is always underestimated. Aiming at the problems of low face resolution and low expression recognition accuracy in public space, an emotion recognition method based on facial expression and body posture is proposed. Firstly, the video data is preprocessed to obtain the input sequence of expression channel and posture channel; then, the emotional features of expression and posture are extracted by deep learning method; finally, fusion and classification are carried out in decision level. The emotion dataset (SCU-FABE) based on public space video is constructed. On this basis, combined with posture emotion recognition data enhancement, the effective recognition of individual emotions in public space is realized. The experimental results show that the recognition rate of expression and posture is 94.698% and 88.024%; fusion emotion recognition rate is 95.766%. The proposed method effectively integrates emotional information expressed by facial expression and body posture, and has good generalization ability and applicability in real scene video data.

Abstract:The traffic signal system controls the order of urban vehicles, and its efficiency directly affects the development of the social economy. This paper takes the traffic signal control system at the intersection as the research object, an improved algorithm is introduced based on the deep deterministic policy gradient (DDPG), in which the feature enhancement and sample deduplication algorithms combined with the characteristics of the traffic environment are designed to improve the performance of the algorithm. By analyzing the operation of the actual traffic system, a traffic simulation platform for intersections is set up based on the SUMO simulation environment. The FEPG algorithm is used to control traffic signals to achieve efficient vehicle traffic. Experimental results show that the algorithm can effectively reduce vehicle waiting time and reduce vehicle emissions.

Abstract:In order to obtain the flat-top beam, an offset reflector antenna that works at 19 GHz-22 GHz is designed using reflector shaping method. Using Zernike polynomial expansion method and the genetic algorithm to optimize reflector shape. The difference between actual and ideal value of the irradiation intensity of a specific area on the far-field radiation surface of the antenna is selected as the objective function to achieve flat-top beam. The simulation results show that irradiation intensity ripple of the antenna is less than 0.6dB and the amplitude is greater than 20.5 dBi within ±8° in the azimuth pattern.

Abstract:With respect to the need for online γ-ray monitoring in the containment of nuclear reactors, a γ spectrometer with high integration, low power consumption, high energy resolution, long endurance and automatic measurement is designed in this paper. A LaBr3(Ce) scintillator detector with high energy resolution is used in the spectrometer. And an active cone-shaped voltage divider circuit is designed to supply power to the detector and to improve the dynamic range of energy response of the spectrometer. Additionally, a low noise charge-sensitive preamplifier circuit is designed to amplify output signal of detector, and a second-order active low-pass filter circuit is designed to shape the front-end signal into a quasi-Gaussian pulse signal. A high integrated multi-channel pulse amplitude analysis circuit is designed by using STM32L4 series microprocessor to complete the analog-to-digital conversion and on-line data processing of the pulse signal and obtain γ energy Spectrum. In addition, we also designed a low-noise high-voltage power supply circuit based on the CC228P-09Y small high-voltage power supply module to provide high voltage for the LaBr3(Ce) detector. The power management circuit powered by lithium battery is designed by using STM32L4 series processor, thus the spectrometer can enter the working mode or standby mode automatically, realizing the automatic γ spectrum measurement function of long endurance time. In the end, a detailed performance test of the spectrometer is carried out: the energy resolution of the spectrometer is 3.0% (@ 662 keV), and the energy response integral nonlinearity is 9.5%. It can work stably for a long time and has the characteristics of low power consumption and long endurance time.

Abstract:Based on the laser waveform control scheme, we propose a method to obtain the water window single order harmonic. The results show that by properly introducing the chirps of two-color laser field, the single order harmonic with the intensity enhancement of one order of magnitude can be obtained. Furthermore, by introducing a half-cycle pulse at the chirped waveform region, the single order harmonic can be extended to the higher energy region, covering the whole water window region. Finally, with the different combinations of chirped pulses and half-cycle pulses, the wavelength tunable single order harmonic in the water window region can be obtained.

Abstract:Based on one dimensional aerodynamic analysis theory, a three-stage centrifugal turbine was designed by using R123 as working fluid. The aerodynamic performance of the centrifugal turbine was studied by numerical simulations. Numerical results showed that the circumferential efficiency of the three-stage centrifugal turbine with equal blades and high straight blades can reach 86.7% under design conditions. Under the off-design conditions, the efficiency increases initially with increasing expansion ratio, reaches a maximum and then decreases. The thermal parameters such as expansion ratio, enthalpy drop and reaction degree of each stage of centrifugal turbine increase from high pressure stage to low pressure stage with the change of expansion ratio of each stage group, and the last stage changes the most.

Abstract:We report the fast neutron flux and spectrum in the PE room at the China Jinping Underground Laboratory (CJPL) with a liquid scintillator detector doped with 0.5% gadolinium (Gd-Ls). The difference between nuclear recoil signals and electronic recoil signals is used to select neutron events in a liquid scintillator detector doped with gadolinium. The signature of gadolinium-captured thermal neutrons is used to time discrimination. The fast neutron flux range of 1~10 MeV measured in the PE room at the CJPL is 4.45×10-8 cm-2 s-1 based on 206 days of data. A similar selection method is used to analyze the degree of α contamination in the Gd-Ls. The α contamination of the natural radioactivity series including 238U, 235U, and 232Th are (0.0227±0.0001) s-1, (0.0329±0.0001) s-1, and (0.1471±0.0002) s-1, respectively. Compared with the fast neutron flux of other deep laboratories around the world, the fast neutron flux of CJPL is at an extremely low level, which is an ideal place for rare-events measurement experiments.

Abstract:To obtain reasonable bond performance parameters of GFRP bars, the indoor pull-out test and numerical simulation are used to study the bond performance between GFRP bars and mortars. Through the pull-out tests of different reinforcement diameters and mortar strengths, the relation curves between bond strength and slip under different working conditions are obtained, and the influence of reinforcement diameter and mortar strength on the bond strength of GFRP bars is revealed. Based on the results of indoor pull-out test, the finite difference software FLAC3D is used to simulate and reproduce the pull-out test of GFRP bars. The back analysis of the bond performance parameters is carried out in FLAC3D, and the calculation formulas of the grouting stiffness and grouting cohesion of GFRP bars are modified. The results show that the bond strength between GFRP bars and mortar is negatively correlated with the diameter of bars, while positively correlated with the mortar strength. In the absence of pull-out test data, the ultimate bond strength of GFRP bars should be one fifth of the compressive strength of mortar to obtain the grouting cohesion. The grouting stiffness of GFRP bars can be calculated by formula of ordinary steel bars, but it should be multiplied by the reduction factor in the interval of (1/10, 1/15).

Abstract:In order to realize the comprehensive simulation of the multi-physics and multi-scale field of the reactor, based on the unified coupling interface concept Interface for Code Coupling (ICoCo) and the unified data transfer model MED library, the space-time neutronics simulation code CORCA-K and the sub-channel code CORTH have been packaged. Furthermore, the coupling between CORCA-K and CORTH was realized by using the supervisor method. The code was verified by the rod ejection cases of 3D LWR core transient benchmark NEACRP. The numerical results show that the CORCA-K and CORTH coupling code based on the unified coupling framework can realize the field data transfer and coupling calculation between CORCA-K and CORTH. The calculation results are in good agreement with those of the CORCA-K coupling interface, and the two results are basically consistent with the benchmark ones.

Abstract:As an important lithium-ion battery, ternary nickel-cobalt-lithium manganese (NCM) battery has a broad development prospect and application value. This paper summarizes the advantages of ternary lithium-ion battery compared with traditional battery, analyzes the components of ternary battery, and focuses on the different recycling methods and reaction mechanisms of ternary cathode materials. The application prospect of NCM ternary lithium-ion battery is prospected. Combined with the new process route of technological innovation and development projects, the problems existing in the present recycling methods, such as the difficulty in separating cathode active substances from aluminum foil and the easy generation of secondary waste liquid, are effectively solved.

Abstract:In order to effectively solve the environmental pollution caused by dye wastewater, a copper ion chelated chitosan magnetic composite was prepared for the adsorption of dye wastewater. The composite Cu@CTS@Fe3O4 was successfully prepared by the coordination chelation of chitosan with copper ion and the introduction of magnetic particles Fe3O4. The structure and morphology of the prepared materials were characterized by FTIR, SEM and TGA. At the same time, the adsorption kinetics and isotherm adsorption of reactive brilliant red (RBR) were studied in detail. The adsorption experiments showed that the adsorption capacity of Cu@CTS@ Fe3O4 to RBR reached the maximum of 831.22 mg/g when pH=2. This study provides some relevant data and theoretical guidance for the application of chitosan-based adsorbents in the field of dye wastewater treatment.

Abstract:In order to explore the allelopathy of leaf litter of Larix kaempferi on native plants, the effects of different concentrations (0.01, 0.05, 0.1 g/mL) of water extracts of Larix kaempferi litters (LkLWE) on seed germination and seedling growth of native plants were studied using petri dish filter paper method and pot soil culture method with 5 native plants in Wolong. The results showed that LkLWE had an effect on the seed germination and seedling growth of 5 native plants.1) The intensity of the comprehensive effect of the allelopathy of LkLWE on seed germination was in order of M.sativa > P.vulgaris > M.officinalis > P.depressa > E.dahuricus. The LkLWE mainly inhibited the seed germination of M.sativa, M.officinalis and P.vulgaris, and the inhibition degree was positively correlated with the concentration of the extract; the seed germination of E.dahuricus and P.dipressa showed a phenomenon of low promotion and high inhibition. 2) The intensity of allelopathic comprehensive effect of LkLWE on the growth of seedlings was in the order of M.sativa > M.officinalis >P.vulgaris > E.dahuricus > P.depressa. Among them, the extract mainly inhibited the seedlings growth of M.sativa and M.officinalis, and was positively correlated with the concentration. The LkLWE has a lo-promoting and high-inhibiting effect on the seedlings growth of E. dahuricus and P. vulgaris, and has always been a positive effect on the growth of P.depressa seedlings. The results suggest some management measures for artificial replanting under Larix kaempferi forest and increasing plant diversity.

Abstract:In order to study the members and classification of protein phosphatase 2C (PP2C) family in Tartary buckwheat and to explore its function in the growth and development of Tartary buckwheat, this study used bioinformatics methods to identify and classify the PP2C genes of Tartary buckwheat (FtPP2C), and its genes structure, conservative motifs, and molecular evolution were analyzed. The results revealed that 81 FtPP2C genes divided into 11 subgroups (A-K), and the sequence characteristics in the same subgroups were similar, but there were certain differences in sequence characteristics among different subgroups. The results also revealed that FtPP2C genes had 14 gene duplication events. In addition, the expression patterns of FtPP2C clade A genes were analyzed by qRT-PCR, and the results revealed that all FtPP2C clade A genes were expressed in five organs (roots, stems, leaves, flowers, and fruits), among them, 8 genes except FtPP2C44 were highly expressed in flowers and fruits; in seedlings, all 8 genes except FtPP2C08 were up-regulated after ABA treatment. The above results revealed that the composition, sequence characteristics, and amplification of the FtPP2C genes. These results also revealed the tissue expression pattern and the expression induced by ABA of FtPP2C clade A genes.

Abstract:In order to solve the problem of heavy metal Cr (Ⅵ) pollution in water, a strain with high resistance and removal rate to Cr (Ⅵ) was screened from the soil contaminated by heavy metals near a leather factory in Chengdu. After identification, it was named Cellulosimicrobium sp. strain C6 (Cellulosimicrobium sp). Based on singlefactor experiments, four factors (pH, temperature, contact time and initial Cr (Ⅵ ) concentration) affecting the removal of Cr (Ⅵ) were optimized by BoxBehnken response surface method. The results showed that when the pH was 7.85, the temperature was 34.07 ℃, the contact time was 2.88 days, and the initial Cr (Ⅵ) concentration was 40.08 mg/L, the maximum removal efficiency of Cellulosimicrobium sp. strain C6 on Cr (Ⅵ) can reach 95.75%. Scanning electron microscope results showed that the surface of the untreated Cellulosimicrobium sp. strain C6 was clear, smooth and dispersed. The surface of Cr (Ⅵ) treated strain was irregular with granular precipitation. Fourier transform infrared spectroscopy analysis showed that the functional groups on the surface of Cellulosimicrobium sp. strain C6 might be related to the adsorption of Cr (Ⅵ). Cellulosimicrobium sp. strain C6 can be used to treat Cr (Ⅵ)containing wastewater .

Abstract:In order to reveal the characteristics of the entire chloroplast genome of Chara globularis and explore its phylogenetic relationship in Characeae, highthroughput sequencing technology was used to assemble and sequence the entire chloroplast genome. The study showed that C. gloublaris is a circular molecule of 180 652 bp in length with a typical quadripartite structure and a 26.6% GC-content. 137 chloroplast genes were successfully annotated, including 94 protein-coding genes, 37 tRNA genes and 6 rRNA genes. There are 2 more protein-coding genes and 3 more tRNA genes than Nitella hyalina. Compared to land plants, C. globularis has four special genes: rpl12, trnL(gag), rpl19, and ycf20. A total of 87 SSR loci were detected in the genome, and most of them were composed of A and T. In addition, C. gloublaris contains a total of 24 989 codons and the codon usage prefers A and T. Leucine (Leu) is the codon that encodes the most amino acids. The phylogenetic tree constructed by the Neighbor Joining(NJ) on the entire chloroplast genomes of 5 species including C. gloublaris. showed that the phylogenetic relationship of C.gloublaris was closer to that of Chara vulgairs. This study analyzed the entire chloroplast genome of Chara globularis, and established its phylogenetic status by using the existing data.