Abstract:The inversion of a mass matrix is often involved in solving partial differential equations by finite element method. Mass lumping can be used to improve the computational efficiency by diagonalizing mass matrix with special numerical integration. In this paper, a fully discrete hybrid stress quadrilateral finite element method for the wave propagation in viscoelastic solid media is presented. To realize the diagonalization of the mass matrix, the Gauss-Lobatto numerical integration with displacement interpolation nodes as quadrature nodes is used. A numerical examples is given to verify the performance of the method.

Abstract:This paper discusses the reconstruction of experimental data of the discrete measurement of γ-ray counting. By establishing the matrix model for the forward direction computation of experimental data, we firstly transform this engineering problem into a mathematical problem of solving indefinite nonlinear equations. Then we present two reconstruction models respectively based on the optimization objective function and the Lagrange multiplier method to find the optimal solution. Numerical experiments show that both reconstruction models can obtain closer results to the true value than the detection value, and the reconstruction result of the second model is more accurate than the first one. Moreover, the second reconstruction model allows the direct using of initial value of the iterative solver.

Abstract:Gaussian distribution， also called normal distribution, plays an important role in mathematics, statistics, physics, engineering etc. Inequalities on Gaussian distribution attract many attentions, in which a famous example is the Gaussian minimum conjecture. In this note, we show that this conjecture holds if and only if n=2.

Abstract:We consider the existence of positive radial solutions to a class of elliptic boundary value problem with gradient term. The existence of positive radial solutions is obtained by using the Leray-Schauder fixed point theorem.

Abstract:Let a,b,n be positive integers and let S={x_1,…,x_n } be a set of n distinct positive integers. Denoted by (S^a) (resp. [S^a]) the n×n matrix having the ath power of the greatest common divisor (resp. the least common multiple) of x_i and x_j as its (i,j)-entry, we iIn this paper study the divisibility among the determinants of power matrices on GCD-closed sets and extend Hong’s theorem obtained in 2003 and the theorems of Chen and Hong obtained in 2020.

Abstract:The use of capsule network in the fields of image and language have progressed tremendously over the past few years, with the extensive research of the capsule network. However, the capsule network has the disadvantages of too many parameters and long training time. The group feedback routing mechanism is a supervised routing strategy called group-routing. The strategy divides the capsules into several groups evenly, and the capsules locally share the conversion weights, thereby reducing routing parameters and computational complexity, and achieving better results in image classification. In this paper, a new text classification model CapsNet-GSR(CapsNet-Grouped capsule based on Static Routing) is proposed based on the capsule grouping method, and the capsule compression and static routing mechanism are also introduced. The model uses capsule grouping to extract local information of the text while reducing parameters. In addition, it uses capsule compression and static routing mechanisms to further improve the quality of the capsule and reduce the number of parameters. The experiment on the 20 news text classification dataset proves that the number of parameters and training time of the proposed model decrease obviously. The experiment results on AG’s news, TREC, and 20 news datasets show that the accuracy of the proposed model is also improved.

Abstract:In order to monitor the combustion state and measure the temperature distribution in the furnace, a threelayer progressive grid temperature field reconstruction algorithm based on acoustic tomography (AT) is proposed. The algorithm first computes the sparse grid temperature information with the least squares method (LSM), and then uses the least squares support vector machine (LSSVM) to establish a fine grid model for the temperature field. In order to further improve the reconstruction accuracy, the parameters of the LSSVM reconstruction model are tuned by the differential evolution algorithm (DE) (Referred to as the LLD algorithm) to establish a detailed temperature description of the entire measured temperature field. Through the reconstruction of three different types of temperature fields provided by Dongfang Boiler Industry Group, the results and error analysis show that the LLD algorithm can describe the temperature distribution information of the measured combustion zone globally and achieve high-precision reconstruction of the temperature field.

Abstract:Drug-Drug Interaction refers to the inhibition or promotion between drugs. In order to solve the problem that the extraction results of the current model are quite different in different relationship categories, this paper proposes a relationship extraction model based on external knowledge. This method first processes the information in the external drug database, constructs a data set with drug description information on which the model is trained and then the optimal model is saved. Finally, the resulting optimal model is combined with the drug relationship extraction model to extract drug relationships, which can make better use of the existing knowledge in drug database, alleviate the problem of large differences in the extraction results of different relationship categories, and improve the extraction result. The experimental results on the DDIExtraction 2013 dataset show that the F1 value of the proposed approach in this paper is 2.47% higher than the current best approaches.

Abstract:In this paper, a new type of five axis groove cutting robot based on machine vision is designed to meet the reaquirements of the groove cutting operation of flat steel. First, the SOILDWORKS model of five axis groove cutting robot is established to verify whether the design of the robot mechanical body can meet the working requirements. Secondly, the DH parameter table and DH coordinate diagram of the robot is defined according to the SOILDWORKS model. Then, the forward kinematics and inverse kinematics of the robot are analyzed through the homogeneous transformation of the robot, and the rationality analysis of the robot structure is conducted from a numerical point of view.Finally, by using MATLAB software, the kinematics modeling and Simulation of the robot is carried out in this paper. The kinematics simulation of the robot is mainly divided into three parts which are the static model simulation of the robot, the motion space simulation and the motion simulation of robot end effector under different path planning. The simulation results of the designed robots in this paper demonstrates the feasibility of the robot mechanical structure design, which provides theoretical support for the design of robot control system and control algorithm.

Abstract:A new efficient dehazing algorithm is proposed to address the failure of the dark channel prior method in bright areas such as the sky and the blur problem at the edges caused by guided filtering. In this algorithm, a novel adaptive segmentation and correction method is first proposed; the bright areas are segmented based on the relative depth of field threshold, and the value of saturation and grey level are used to calibrate the dark channel in the bright areas. Then, the weighted aggregate guided filtering instead of guided filtering is adopted to refine the initial transmittance to solve the problem of edge blur caused by guided filtering. Finally, an effective brightness correction method is proposed; the restored image is converted to HSV color space to equalize brightness, and the results before and after brightness equalization are linearly weighted to obtain the final result by using relative fog density average as the weigh. The experimental results shows that the proposed algorithm can segment the bright area accurately, restore the image texture clearly and remove the fog thoroughly; the maximum improvement of peak signal to noise ratio, average gradient, information entropy are 34.46%, 99.49%, 21.18%, respectively, by comparing with the previous results.

Abstract:Based on related researches on the index system and evaluation approache of green hydropower at home and abroad, with respect to the characteristics of cascade hydropower development environmental protection in river basin t and the life cycle management of hydropower projects, this study constructed a three-tiered comprehensive green hydropower evaluation index system comprising river health, environment protection and social economy, established an improved matter-element extension model with variable weight for green hydropower rating. This study selected Shenxigou hydropower station which has been built and operated for a long time as the typical hydropower station for empirical analysis.We obtained the score of each evaluation index by computing the data which have been collected and investigated, then utilized the improved matter-element extension model with variable weight to assess green hydropower grade of this power plant, and then analyzed the sensibility of the evaluation index, thus having verified the applicability and effectiveness of this index system and evaluation model. According to the analysis results of green hydropower evaluation, it is necessary to optimize and improve the environmental management of hydropower development in the basin, so as to further improve the evaluation level of green hydropower and promote the healthy and sustainable development of hydropower projects in the basin.

Abstract:Aiming at the multi-objective optimization problem that it is difficult to effectively improve current efficiency and reduce DC energy consumption in the aluminum electrolysis manufacturing system (AEMS), a functional evolutionary operator-based NSGA-II (FEONSGA-II) is proposed in this paper. Based on the stable operation of the system, the Pareto non-inferior solution set can be obtained to meet the demands of increasing the efficiency and reducing the consumption of aluminum electrolysis. The crowding entropy is used to update the population, and the distribution of the front solution set at all levels is accurately estimated. To reduce the possibility of destroying the excellent solution set, we introduce arithmetic crossover with a new α-function operator. Then, according to the Gaussian Cauchy variation characteristics, the perturbation related to the number of iterations is generated to expand search ranges and accuracy. Finally, the standard test function is used to detect the performance of the algorithm and three comparison algorithms are applied to solve the aluminum electrolysis example. The experimental results show that the proposed algorithm can obtain the Pareto optimal solution set with uniform distribution, which is conducive to the reference decision of aluminum electrolysis plant to achieve the purpose of improving efficiency and reducing consumption.

Abstract:By regulating the nonlinear chirp waveforms, a method to extend the harmonic cutoff and enhance the harmonic intensity by combining two kinds of nonlinear chirp forms has been proposed. The results show that by appropriately adjusting the second-order and third-order chirp parameters, the chirp delays and the other laser parameters of the combined pulse, the laser waveforms can be optimized. Driven by the optimal waveforms, the harmonic cutoff and harmonic radiation intensity can be significantly increased, which can lead to the generation of the isolated pulses with the durations of 39 as.

Abstract:The traditional pressure vessel safety margin characterization model does not consider the time-varying nature of the crack propagation process, which makes it impossible to accurately reflect the residual safety margin. This paper establishes a large pressure vessel residual safety margin model based on the velocity product concept. The form of crack growth directly affects the determination of safety margin, so the Paris formula is used to obtain the crack growth law formula with the closure effect, and the theory of Newman and Raju numerical calculation of the stress intensity factor is used to obtain the correlation function of the changes in the depth and length of different cracks. Taking surface cracks as an example, the safety attenuation path is obtained based on the correlation function model, then the characterization change of the path velocity product safety margin model is calculated, and the path velocity product safety margin model is evaluated from the perspective of life safety margin. It is shown that as the crack propagation changes at different speeds, the safety evaluation results are more consistent with the actual safety margin changes, and provides new ideas for engineering applications.

Abstract:To study the thermal stress of thermal barrier coating (TBC) piston, a new three-dimensional control volume finite volume method (CV-FEM) has been developed for thermal stress problem with composite material. The numerical discrete process of the governing equation is given in detail with 10-node high-order tetrahedral grid. Using the staggered grid technique, the unknown variables are defined at the cell vertex, while the physical parameters of material are defined at the cell center．The developed high-order CV-FEM was used to simulate the thermoelastic fields of annulus, the predicted results show good agreement with the ANSYS results. Then, the developed CV-FEM was used to simulate the thermoelastic field of the piston with laminated material and functional graded material (FGM). The results show that the maximum temperature is located in the boundary area between the combustion chamber and the top surface, and the maximum stress is around the cohesive layer, the maximum stress amplitude cannot be effectively reduced by changing the composition and distribution of the laminated TBC piston, or by changing the material gradient coefficient of FGM TBC piston, the maximum stress in the laminated and FGM pistons can be reduced effectively by introducing FGM which material properties gradually change from metal matrix to adhesive into the cohesive layer, the maximum stress can be decreased about 20%～30%, and the stress concentration problem can be improved significantly.

Abstract:In order to achieve infrared stealth under different background temperatures, it is necessary to study infrared stealth materials with adjustable emissivity. In addition, multi-band compatible stealth technology has important research value in modern mili-tary, science and technology. In this paper, a metamaterial absorber with a single multi-layer structure is designed to realize efficient multi-spectral manipulation. Ge2Sb2Te5 (GST) is a phase-changing material. Crystalline GST and amorphous GST have different infrared electromagnetic properties. Utilizing this property of GST, the maximum absorptivity of the designed structure can be controlled from 94.93% to 9.19% in the wavelength range of 8~13 μm. Moreover, the intermediate GST can be obtained by controlling the external conditions, and the absorptivity of the structure to the electro-magnetic wave can be changed continuously. At the same time, the structure has tunable structure color based on interference effect, and the surface color of the device can be tuned by changing the thickness of the top film. Therefore, the independent tuning of electromagnetic wave in both infrared and visible bands is realized at the same time. The metamaterial absorber has the potential application of infrared-visible compatible stealth.

Abstract:Using the first-principles method based on density functional theory, the luminescence mechanism of Mn2+/ Eu3+ co-doped Zn2GeO4 long afterglow system was studied theoretically. The crystal structure model of Mn2+/ Eu3+ co-doped Zn2GeO4 was constructed based on the experimental results of related literatures. Studies show that Mn2+ doping makes the crystal structure of Zn2GeO4 more stable, and at the same time, it causes the charge delocalization in the crystal, Mn2+ ions become the luminescence centers; Eu ions exist in the Zn2GeO4 crystal with valence of +3 and become the trap centers. On this basis above, the long afterglow luminescence mechanism model of Mn2+/ Eu3+ co-doped Zn2GeO4 crystal system was discussed.

Abstract:In this study, a constructed wetland-microbial fuel cell system was constructed to treat pesticides represented by Atrazine, and to understand the pesticide treatment efficiency and treatment mechanism of the system. The results show that the system has a good treatment performance for Atrazine. When the concentration of Atrazine is less than 4 mg/L, the treatment performance of the system remains stable above 85%. Under the condition of Atrazine concentration of 4 mg/L, the system has the best power generation performance. At this time, the average daily voltage, maximum power density and current density of the system output are 284.4 mV, 19.64 mW/m3 and 46.09 mA/m3, respectively. Pesticides have a significant impact on the microbial diversity of the system, but have no significant impact on microbial gene function, and have less impact on system bacteria than the electric field. The dominant bacteria phylum of the system includes the Proteobacteria, and the dominant electrochemically active bacteria includes the Bacteroides and Firmicutes, while the dominant bacteria phylum degrading pesticides includes the Actinobacteria, the dominant bacteria classes includes Alphaproteobacteria and Actinobacteria, and the dominant bacteria genus includes Christensenellaceae_R-7_group.

Abstract:300M steel is an important material for fabricating main bearing structure of aircrafts. However, the surface oxidation and decarburization of this material will occur in varying degrees during the heat treatment of die forging process, which seriously affects the yield of forgings. Herein, the decarburization behavior of 300M steel under different heat treatment conditions is systematically studied. The morphology and thickness of the oxide layer are analyzed by scanning electron microscope (SEM) and the corresponding Energy Dispersive Spectrometer (EDS). The variation of decarburization depth is measured using microhardness method. The evolution of decarburization behavior of 300M steel under different heat treatment conditions is clarified, and the effect of anti-oxidation coating on the depth of decarburization layer is presented. The results show that the dense oxide layer formed on the surface of 300M steel during heat treatment has distinct protective effect, which can prevent the matrix carbon from diffusing to the surface, thus reduce the depth of decarburization layer. There is a balance between the diffusion rate of carbon and the surface oxidation rate at different temperatures, and the application of anti-oxidant coating on the surface of 300M steel will change the original balance. The results of microstructure analysis show that the full decarburization zone on the surface of 300M steel is composed by pearlite or ferrite, and the semi-decarburization zone is mainly martensite and precipitated carbide. We also expound the evolution of the near-surface microstructure of 300M steel with the increase of holding time. Finally, the coupling mechanism of decarburization and oxidation on the surface of 300M steel is revealed from the perspective of thermodynamics. The results of this paper are expected to provide important data and theoretical support for establishing optimization process of die forging and developing heat treatment protection technology of 300M steel.

Abstract:In order to explore the new antibacterial strategy against Mycobacterium abscessus, this study used the microplate alamar blue assay (MABA) method to determine the minimum inhibitory concentrations (MICs) of fusidic acid and other drugs on the standard strains and clinical isolates. The checkerboard method was used to determine the antibacterial effect of fusidic acid combined with drugs, while the minimum bactericidal concentrations (MBCs) were determined by the plate coating method. The results showed that the MIC90 of fusidic acid, azithromycin, ceftriaxone sodium, bedaquiline alone against the standard strain of M.ab was 50 μg/mL, 6.25 μg/mL, 3.13 μg/mL, and 3.13 μg/mL, respectively. And the MBCs of those alone against the standard strain of M.ab were 50, 12.5, 3.13, 6.25 μg/mL, respectively. The fractional inhibitory concentration index (FICIs) of fusidic acid combined with azithromycin ranged from 0.09~2.0. Fusidic acid has good antibacterial activity against M. ab in vitro, and the combination of fusidic acid with azithromycin showed an obvious synergistic effect in vitro bacteriostatic effect on both standard and clinical strains of M.ab, which significantly reduced the MICs and MBCs of the drug, and the combination with ceftriaxone sodium showed synergistic on standard strains and additive effect on clinical strains. After combined with bedaquiline, it showed additive effects on standard strains while irrelevant effects on clinical strains.

Abstract:In order to enrich the microbial resources that can be used in functional foods, a Bacillus (XQ) strain with high production of extracellular polysaccharide and lactic acid was isolated from the fermented rice cake workshop in Huaiyuan, Sichuan，and it was identified as Bacillus pumilus. The lactic acid content detected by HPLC was 8 mg/mL and the concentration of crude exopolysaccharide detected by the phenol-sulfuric acid method was 7.16 mg/mL. It was determined by the filter paper method that the extracellular polysaccharides and fermentation broth had inhibitory effects on common foodborne pathogens Salmonella, Staphylococcus aureus, and Escherichia coli. The extracellular polysaccharide was further separated to obtain neutral polysaccharides E1 and acidic polysaccharides E2. When the concentration was 10 mg/mL, the scavenging activity of E1 on hydroxyl radicals was 3.24%, while the scavenging activity of hydroxyl radicals of E2 was as high as 84.58%; the scavenging activities of E1 and E2 on DPPH free radicals were 26.07% and 47.03%, respectively. E2 also had obvious anti-tumor activity. When the concentration was 4 mg/mL, the growth inhibition rate of E2 on A549 cells could reach 81.30%, and when the concentration was 6 mg/mL, the growth inhibition rate of E2 on HepG2 cells was 53.40%. In the simulated gastrointestinal tolerance experiments, it was found that XQ has a high tolerance to trypsin, pepsin and bile salts. In terms of safety, XQ has not been found to have hemolysis, is not resistant to Gram-positive antibiotics, and has good drug safety. In summary, this study indicated that XQ can be used as a potential probiotic.

Abstract:In order to explore the possibility of tobacco rattle virus overexpression and silencing system for oil-related gene research, this study cloned Arabidopsis thaliana WRI1 and FAD2 genes, and constructed TRV overexpression and silencing vectors, respectively. The transient infection technique was used to infect Nicotiana benthamiana, and the material was collected for RT-PCR and fatty acid content detection. The results showed that the WRI1 gene and related fatty acid synthesis genes ACP1, KAS1, and BCCP2 in both infected and non-infected leaves were significantly up-regulated in Nicotiana benthamiana overexpressing the WRI1 gene, and the fatty acid content test results showed that the levels of fatty acids increased 16% and 28%, respectively. In Nicotiana benthamiana plants that silenced the FDA2 gene, the content of polyunsaturated fatty acids was found to be reduced by approximately 25% and 24%, respectively. Therefore, it is possible to use TRV system to study lipid related genes.

Abstract:To explore the function of pectin methylesterase (PME) in forest plants, in this study, we cloned the Arabidopsis thaliana PME34 homologous gene PtoPME34-1 from Populus tomentosa, and elucidated the biological function of this gene in Populus tomentosa. Bioinformatics analysis shows that the similarity between the PtoPME34-1 gene of Populus tomentosa and the PtrPME34-1 of Populus tomentosa is 100%, and the similarity of the sequence with AtPME34 of Arabidopsis thaliana was 93%. Tissue specific expression analysis shows that PtoPME34-1 gene is expressed in all tissues, with higher expression levels in the basal stems and xylem, and the lowest expression level in the old leaves. The results of subcellular localization show that GFP- labeled PtoPME34-1-GFP fusion protein is localized in the cell wall of tobacco leaves. The overexpression of PtoPME34-1 gene significantly improved drought resistance of Populus tomentosa. The double mutants of Populus tomentosa PtoPME34-1 and PtoPME34-2 increased the degree of pectin methylesterification level and drought resistance. These results confirm that PtoPME34-1 plays an important role in regulating plant development and drought stress resistance.

Abstract:This paper studies a version of vehicle routing problem with spatial-temporal correlated stochastic travel times in real road networks. First,a two-stage stochastic optimization model is established for this problem. An intelligent stochastic optimization method is then proposed to solve the model, in which an efficient intelligent optimization algorithm is developed to find candidate solutions, and the scenario generation technology is adopted to generate spatial-temporal correlated stochastic travel time scenarios to evaluate the solutions. This paper proposes a hybrid particle swarm optimization algorithm combined with a variable neighbourhood descent algorithm to perform effective optimization. Finally, a series of testing instances are established based on the road network of Beijing to verify the effectiveness of the hybrid particle swarm optimization algorithm. The experimental results show that considering the spatial-temporal correlation of stochastic vehicle travel times in real traffic environment will affect the best vehicle routing decisions.

Abstract:Promoting the sharing of big data is the key to development and prosperity of the sharing economy, and it is of great practical significance to study the influence mechanism of data sharing. Based on consumers' risk attitudes and corporate privacy protection methods, this paper constructs a game model of data sharing between enterprises and consumers, in which the mechanism that affects data sharing behavior is analyzed and specific policies are recommended. The main findings of this paper are: (1) the risk-biased consumers’ data sharing behavior is mainly affected by factors such as data leakage losses and data protection cost differences. (2) The risk aversion of risk-averse consumers is highly correlated with the game results of data sharing. For the consumers who have a moderate level of risk aversion, there are dual equilibria when the loss caused by data leakage is greater than the difference between the cost of high and low privacy data protection. (3) When the proportion of risk-biased consumers is high, the behavior of risk-averse consumers to use the high quality of sharing data will be increased, while the enterprises will reduce the high-quality protection behavior on protecting consumers' privacy.

Abstract:Informal governance can coordinate symbiotic relationships and behaviors among members, promote interdependence and interaction among members, and promote the healthy symbiotic development and value co-creation of the innovation ecosystem. Based on the social embedding theory and organizational ecology, this paper summarizes four types of informal governance: trust, reputation, cooperative culture, and joint sanctions based on existing research. Using the Logistic model, we construct a symbiosis model of the informal governance influence on the symbiosis relations evolution among members of the innovation ecosystem from the perspective of symbiosis theory, and conduct evolutionary stability analysis and simulation of the symbiosis model. The research results show that the symbiosis evolution of members of the innovation ecosystem depends on the strength of the symbiosis coefficient between members. Among them, the symbiosis coefficient of trust, reputation, and cooperative culture has a positive impact on the symbiosis evolution of system members, which is conducive to the formation of mutual symbiosis. The impact of joint sanctions on the symbiosis and evolution of system members is both positive and negative, which may produce parasitic, partial or reciprocal symbiosis. The income of the symbiosis and stable state of system members is affected by the symbiosis coefficient of informal governance and the maximum income of the main body. Informal governance affects the evolution of enterprises in the innovation ecosystem to a mutually beneficial symbiosis relationship, and provides enlightenment for the formulation of informal governance of enterprises, the realization of value co-creation and the healthy operation of cooperation and symbiosis of the innovation ecosystem.