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28 June 2022, Volume 48 Issue 3 Previous Issue    Next Issue

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Materials Science and Engineering

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Preparation of nanoporous Co phosphide and its electrocatalytic performance for hydrogen evolution LI Chang-feng, ZHOU Qi, WANG Deng-hui, LIN Wen-bin 2022, 48 (3):  1-6.  Abstract ( 178 )   PDF (3789KB) ( 303 )   Save Nanoporous Co, NiCo(OH)2/Co and NiCo(OH)2-P composite electrodes were prepared by Dealloying, Hydrothermal synthesis and Chemical vapor deposition. The phase, morphology and structure of the electrode were characterized by the X-ray diffractometer (XRD) and scanning electron microscope(SEM). In 1 mol·L－1 KOH solution, the electrocatalytic hydrogen evolution properties of the electrode were measured by the linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The results show that the properties of nanoporous Co, NiCo(OH)2/Co, NiCo(OH)2-P electrode materials increase in turn. The overpotential of nanoporous NiCo(OH)2-P after chemical vapor deposition(CVD)phosphorization is 139 mV at 10 mA·cm－2 current density, and Tafel slope is 123.57 mV·dec－1, the double layer capacitance is 30.16 mF·cm－2. After 1 000 cycles of cyclic voltammetry, nanoporous NiCo(OH)2-P electrode show excellent hydrogen evolution reaction (HER) stability with only 7 mV change of hydrogen evolution overpotential at 10 mA·cm－2 current density. References | Related Articles | Metrics

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Crystal characteristics of nugget zone of friction plug welded joints for 6082 aluminum alloy LI De-fu, WANG Xi-jing 2022, 48 (3):  7-12.  Abstract ( 207 )   PDF (4292KB) ( 330 )   Save In order to reduce the requirements of equipment, on the basis of friction stir welding filling technology with solid state joining, the friction plug repair welding tests were carried out by shoulder auxiliary heating methods for 6082 aluminum alloy, and well-formed repair welding joints were obtained. EBSD analysis of nugget zone of joint shows that the grain refinement is significantand there is obviouspreferred orientation. With the increase of rotating speed from 1 800 r/min to 2 000 r/min, the grain shape changes from equiaxed grain to linear hammer, the average grain size increases, and thecomposition of high-angle grain boundary decreases slightly. The mixed texture of deformation, shear and recrystallization is found in the nuggest zone, and the composition of recrystallization texture increases with the increase of rotational speed. With the increase of the rotating speed, the effectof the increasing speed on the deformation rate decreases, while the effectof the increasing speed on the recrystallization increasesaccordingly. References | Related Articles | Metrics

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Example of analytical solution of welding temperature field for infinite plate WANG Yi, YIN Xiang, ZHOU Kai, WANG Xin-min, WANG Xiao-jun 2022, 48 (3):  13-16.  Abstract ( 201 )   PDF (810KB) ( 300 )   Save Based on the idea of combination of equation and graph, welding temperature field was analyzed by example plate analytical solution under the action of mobile line heat source. The three-dimensional distribution graph and the two-dimensional temperature and isotherm curve of the temperature field of the infinite plate were accurately drawn. The results showed that the temperature increases slowly and then decreases rapidly with x variation when y takes a fixed value. The highest temperature point moves slowly to the left with the increase of y value. The temperature is symmetric about straight line y=0 mm when x takes a fixed value and takes a maximum value when y=0 mm. A single isotherm is similar to an ellipse and is symmetric about its horizontal axis. The front of the temperature field has dense lines and large temperature gradient, while the back of the temperature field has sparse lines and small temperature gradient. Then the surface shape and size of welding pool in the case of example are calculated, the molten pool looks like an ellipse and is 30.16 mm long, 22.13 mm wide. References | Related Articles | Metrics

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Non-isothermal crystallization kinetics of PA56/66 copolyamide FAN Song-hong, GAO Jun-fei, GU Qun, ZHANG Jian-qiang 2022, 48 (3):  17-26.  Abstract ( 342 )   PDF (8127KB) ( 178 )   Save The crystallization kinetics of semi-crystalline polymer has a great influence on the structure and properties of polymer materials, and it is a important parameter in the process of polymer processing. The non-isothermal crystallization behavior of PA56,PA66 and PA56/66copolyamide was studied by differential scanning calorimetry (DSC). Jeziorny and Mo’s method were used to describe the non-isothermal crystallization kinetics of PA56, PA66 and PA56/66 copolyamide. The activation energy of non-isothermal crystallization of PA56, PA66 and PA56/66 copolyamide was calculated by Kissinger’s method. The results show that Jeziorny method can describe the main part of crystallization of PA56, PA66 and PA56/66 copolyamide, but it can not describe the whole process of them. Mo’s method can well describe the whole non-isothermal crystallization process of PA56, PA66 and PA56/66 copolyamide. Avrami index n shows that PA56, PA66 and PA56/66 copolyamide have more complex nucleation and crystal growth mechanism. PA56 is introduced into PA66 matrix at molecular level to change its crystal structure and accelerate its crystallization rate. References | Related Articles | Metrics

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Effect of glass powder/silica fume mixture on durability of concrete under corrosive environment WU Duo-ming, WANG Jin-man, WANG Xin, SHI Xu-dong 2022, 48 (3):  27-34.  Abstract ( 323 )   PDF (2559KB) ( 239 )   Save Based on the species and contents of corrosive ions in the soil of Golmud area, the composite solutions of Na2CO3, NaCl, Na2SO4 and MgSO4 were designed for full immersion test, the influence of glass powder/silica fume mixture on the durability of concrete was studied by the variation of relative quality evaluation parameter (ω1) and relative dynamic modulus of Elasticity (ω2) .The influence of glass powder/silica fume mixture on the hydration reaction of cementitious materials under standard curing condition was analysed and the microcosmic mechanism of glass powder/silica fume mixture concrete corroded incompound salt solution was discussed. The service life of concrete corroded by compound salt solution was predicted according to Wiener theory.The results showed that the degradation range of concrete in the corrosion environment of compound salt solution is different with the change of glass powder content. The hydration products of cementitious materials are not affected by the addition of glass powder/silica powder under standard curing condition, and the pozzolanic effect of SiO2 is still obvious after curing from56 d to 120 d.When the content of glass powder is 10% and silica fume is 6%,the air hole structure of the concrete is improved, so the average air hole diameter of the concrete is smaller than that of the concrete without glass powder and silica fume. The glass powder should not exceed 10% when glass powder/silica powder is added to concrete. References | Related Articles | Metrics

Mechanical Engineering and Power Engineering

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Thermal error modeling analysis of CNC machine tool based on optimized least squares support vector machine LI You-tang, TANG Lei-wu, HUANG Hua, WU Rong-rong 2022, 48 (3):  35-41.  Abstract ( 261 )   PDF (2275KB) ( 364 )   Save The thermal error of CNC machine tools is one of the main factors that reduce the accuracy of the machining operation. For the establishment of the thermal error model, combined with the cuckoo algorithm random Levi flight mechanism, the least squares support vector machine structure risk minimization and linear programming advantages, a thermal error modeling method is proposed based on the least squares support vector machine which optimized by cuckoo algorithm. When the least squares support vector machine transforms the low-dimensional nonlinear problem into the high-dimensional linear problem, a hybrid kernel function is constructed, and the cuckoo algorithm is used. The penalty factor γ, the kernel width parameter σ and the mixed kernel weight λ of the least squares support vector machine is optimized by cuckoo algorithm. Taking the GMC2000A machine tool as the experimental object, clustering analysis and modeling analysis of the thermal error data are carried out. The prediction comparison analysis concluded that the error model established based on the cuckoo algorithm to optimize the hybrid kernel least squares support vector machine has achieved good prediction results, and is significantly better than the predictive effect of BP neural network model and the unoptimized least squares support vector machine model. References | Related Articles | Metrics

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Rolling bearing fault data set dimension reduction method of improved D-t-SNE ZHAO Rong-zhen, XUE Yong, WU Yao-chun 2022, 48 (3):  42-49.  Abstract ( 184 )   PDF (3658KB) ( 227 )   Save Aiming at the problem that the traditional dimensionality reduction method is difficult to maintain the local and global geometric structure characteristics of the datasets, geodesic distance is selected as the measurement index, and an improved t-SNE fault data set dimensionality reduction method is proposed. In this algorithm, firstly, the multi-domain high-dimensional fault data set of denoising vibration signal is extracted and normalized, then D-t-SNE algorithm improved by GD index is used to reduce the dimension of high-dimensional fault data set, remove the redundant information, and then identify the fault modes of the low-dimensional feature subsets through different classifiers. Taking UCI data set and the simulated fault data set of the double-span rotor test bench as experimental objects, the above methods are verified and compared with the implementation results with SNE and t-SNE. The results show that this method can reduce the dimensionality of high-dimensional fault data set, thus it can reduce the difficulty of fault classification and improve the performance of fault identification accuracy. This study can provide a theoretical reference for reducing the scale of the original fault feature data set of rotating machinery, reducing the difficulty of fault classification as well as improving the visualization of fault identification results. References | Related Articles | Metrics

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Fault analysis and structure improvement of multi stage driving machine of performance stage wagons NIU Zhan-hai, WANG Xue, WANG Ya-bin, YU Xiao-qin 2022, 48 (3):  50-55.  Abstract ( 131 )   PDF (4066KB) ( 126 )   Save Stage wagon driver is the core component to realize the accurate and stable operation, prolong the service life and reliable start and stop of performance platform. In view of the vibration and noise of the traditional rack and pinion stage wagon when it is driven from the first stage to the second stage, the structure of the driving machine is improved and designed through fault analysis. The specific work includes: rounding the end of the rack to gradually mesh, adding spring device to reduce the impact, using frequency conversion speed control system to ensure the synchronous operation of the multi-stage drive machine, and using elastic sleeve pin coupling to drive the gear to drive the rack. Based on joint simulation of Solidworks and Adams, the instantaneous contact stress of gear rack meshing of the improved driving machine is analyzed. Compared with the traditional driving mechanism, the improved driving mechanism designed by the method proposed in this paper makes the stage wagon run well, and its vibration and noise are reduced compared with the traditional rack and pinion drive stage wagon. References | Related Articles | Metrics

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Study on influence of tip clearance on external characteristics and cavitation performance of axial flow pump ZHAO Wei-guo, CHENG Chao, XUE Zi-yang 2022, 48 (3):  56-64.  Abstract ( 267 )   PDF (7407KB) ( 239 )   Save In order to explore the effect of tip clearance on the external characteristics and cavitation performance of the axial flow pump, based on the modified SST k-ω turbulence model and Z-G-B cavitation model, the numerical simulation of the 350ZQ-70 submersible axial flow pump in different tip clearance was carried out to compare and analyze the external characteristic, the pressure pulsation and the distribution of cavitation volume fraction in the impeller passage. The results show that the pump head and efficiency decrease with the increase of the tip clearance, the flow instability phenomenon is obviously strengthened under the condition of small flow, and the hump phenomenon appears in the head curve. Cavitation of inlet edge is more likely to occur near the hub than near the shroud. At the design flow rate, cavitation of tip clearance first appears in the middle of the blade, not at the blade inlet. The cavitation at the back of the blade will affect the pressure distribution on the working face of adjacent blades. There is a critical value of clearance, before this value, the increase of the tip clearance mainly reduces work capacity of the impeller, and has little effect on cavitation performance; beyond this value, the stability of the leakage vortex decreases and the pressure pulsation increases. For the test pump, the critical value is between 1.5~2 mm; The degree of cavitation of inlet is reduced with the increase of clearance; According to the assembly structure of axial flow pump impeller, in the light of protecting the impeller body, considering the work capacity and operation stability, it is more appropriate to select a clearance of 1.5 mm for the test pump. References | Related Articles | Metrics

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Abnormal power data cleaning method of the wind turbine based on improved DBSCAN LI Lin, DONG Bo, ZHENG Yu-qiao 2022, 48 (3):  65-70.  Abstract ( 157 )   PDF (1187KB) ( 332 )   Save The anomalous power data of wind turbine are difficult to clean effectively, an improved DBSCAN method was proposed. Firstly, the data set was segmented discretely. Then, the parameters of DBSCNA algorithm were estimated adaptively and clustered in each discrete interval. Ultimately, the statistical feature similarity was calculated to correct the clustering results. The proposed method is validated with the measured data of the wind turbine SCADA system in a wind field of 2.5 MW. The findings indicate that the recall rate, accuracy rate and F1 value of the improved method are 97.97%, 97.97% and 97.85%, respectively. The improved method can effectively clean the wind turbine power data set, and the improved method is more stable when the data set is changed. References | Related Articles | Metrics

Chemical Industry and Light Industry

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Preparation of mitomycin analogs mediated by laccase/lipase and optimization using response surface method XUE Xiao, LI Kai-yuan, LIU Cui, DENG Ya-shan, XU Hui, WANG Fan-ye 2022, 48 (3):  71-76.  Abstract ( 151 )   PDF (2250KB) ( 97 )   Save Mitomycins and its analogs have been widely used for treating various tumors. In order to obtain excellent yield and environmental friendliness, an efficient one-pot process for the synthesis of 2-(butylamino)-3-methyl-1, 4-benzoquinone (c), a mitomycin-like compound by the domino reaction of 2-methylbenzene-1, 4-diol and butylamine using laccase/lipase as co-catalysts, has been developed. In the work, the process proposed here was improved by optimizing the relevant factors using the response surface methodology. The optimum conditions were obtained as follows: molar ratio of 2-methylbenzene-1, 4-diol to amine was 1.16∶1, activity ratio of laccase to lipase was 1.14∶2 and reaction temperature was 38.9 ℃, in which the highest yield was 87.17%. The yield model was established, which considered the effects of the amount of 2-methylbenzene-1, 4-diol to amine, the activity ratio of laccase to lipase and the reaction temperature on the yield and could accurately predict the yield (R=0.994 1). The results obtained indicate that this process may be useful as a green alternative process forhigher yield production of mitomycin analogs. References | Related Articles | Metrics

Automation Technique and Computer Technology

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Output feedback H∞ control of cyber-physical systems triggered by two terminal dynamic events WANG Zhi-wen, CHEN Wan-jie, SUN Hong-tao 2022, 48 (3):  77-85.  Abstract ( 236 )   PDF (1879KB) ( 297 )   Save This paper is concerned with the dynamic output feedback control of cyber-physical systems with two terminal dynamic event triggering strategy H∞control problem. Firstly, the closed-loop system is modeled as a linear system with two interval time-varying delays based on an input delay method and a delay partition method. The internal dynamic variables are introduced into the event triggering strategies of sensor controller and controller actuator channels, respectively, and the communication mechanism of asynchronous dynamic event triggering strategy is established to reduce the amount of data transmission by enlarging the inter-event intervals. Secondly, to ensure the stability of the closed-loop system, asymptotic stability criteria satisfying H∞ performance is derived, by applying the Lyapunov-Krasovskii functional approach. Based on this stability criterion, the co-design of dynamic output feedback controller and dynamic event triggering strategy are realized. Furthermore, it is proved that minimum inter-event time of event generator are lower bounded by a positive scalar, which thus excludes Zeno phenomenon. Finally, an example of satellite system is given to illustrate the effectiveness of the proposed strategy. References | Related Articles | Metrics

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Rolling bearing fault diagnosis method based on residual neural network ZHU Qi-xian, LIANG Hao-peng, ZHAO Xiao-qiang, SONG Zhao-yang 2022, 48 (3):  86-93.  Abstract ( 295 )   PDF (2374KB) ( 454 )   Save Because the rolling bearing has been working for a long time in an environment with complex and changeable working conditions and large noise interference, the bearing fault diagnosis method has a poor diagnostic effect under variable working conditions, aiming at this problem, a method of rolling bearing fault diagnosis based on residual neural network is proposed. First, the time domain signal data of rolling bearing is used as the input. Because the signal has a strong time-varying nature, the data pooling layer is improved for this characteristic. The improved data pooling layer is constructed by using three consecutive convolution layers in series. The purpose is to effectively extract feature information of the vibration signal and reduce the calculation amount of residual neural network parameters. Then a kind of dilated residual block combined with dilated convolution and residual block is designed for feature information learning. Finally, the dropout layer is added after the full connection layer to discard a certain proportion of neurons, which can effectively avoid the negative effects of over fitting. The bearing data sets of Case Western Reserve University is used for simulation experiment, and compared with SVM+EMD+Hilbert envelope spectrum, BPNN+EMD+Hilbert envelope spectrum and Resnet, the results show that the proposed method has higher diagnosis accuracy, stronger noise resistance and generalization ability in the fault diagnosis of rolling bearing under variable working conditions. References | Related Articles | Metrics

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Sentiment analysis of Chinese text based on feature fusion ZHAO Hong, FU Zhao-yang, WANG Le 2022, 48 (3):  94-102.  Abstract ( 301 )   PDF (1771KB) ( 659 )   Save To address the problems that the existing methods cannot comprehensively consider the semantic information of text in terms of syntactic structure, contextual information and local semantic features, a feature fusion-based Chinese text sentiment analysis method is proposed. Firstly, Jieba word segmentation tool is used for word segmentation and part of speech tagging of the review text, and a word vector training tool GloVe is used to obtain pre-trained word vectors with part of speech. Then, the word vector is used as the input of BiGRU and TextCNN with self attention respectively. The global features are extracted from the syntactic structure and the contextual information of the text using BiGRU with Self-Attention, and the local semantic ones are extracted using TextCNN. Finally, the global features and local semantic features are integrated, and Softmax is used for text sentiment classification. The experiment result shows that the proposed method can effectively improve the accuracy of text sentiment analysis. References | Related Articles | Metrics

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An improved grey wolf optimization for solving flexible job shop scheduling problem ZHANG Qi-wen, WANG Chao 2022, 48 (3):  103-109.  Abstract ( 228 )   PDF (1364KB) ( 434 )   Save This paper focuses on the flexible job shop scheduling problem and proposes an improved gray wolf optimization (IGWO) algorithm, with the goal of minimizing the maximum completion time. A two-phase coding method is used to construct the relationship between the individual locations and the scheduling scheme. The initial population method based on the heuristic rule is used to improve the quality of initial solution. In order to balance global search and local search, a hyperbolic-tangent-function-based non-linear convergence factor formula is proposed, in the individual update stage of the algorithm, a weighting method based on fitness value is proposed, the variable neighborhood search algorithm is embedded into the decision-making layer of the algorithm. Simulation results show that the algorithm is effective in solving the flexible job shop scheduling problem. References | Related Articles | Metrics

Architectural Sciences

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Study on mechanical properties of buckling-restrained braces with ductile cast connections under uniaxial loading YIN Zhan-zhong, ZHANG Xian-dong 2022, 48 (3):  110-114.  Abstract ( 170 )   PDF (1595KB) ( 128 )   Save In order to improve the high residual stress of traditional beam-column joints, 5 buckling-restrained braces of ductile casting connectors with different parameters was tested subjected to axial compression loading, and the length of the energy dissipating section of the casting connectors and the width-to-thickness ratio of the energy dissipating plate were analyzed. The effect of the stiffener width-thickness ratio and other parameters on the mechanical properties such as the bearing capacity, ductility and stiffness of the specimen is analyzed. The results show that the buckling-restrained braces with ductile casting connector has good bearing capacity, ductility and rigidity, and its bearing capacity is proportional to the length of the energy dissipating section of the connector and the width to thickness ratio of the energy dissipating plate. This new type of support concentrates the inelastic deformation of the structure on the ductile casting connector, protects the safety of the rest of the structure, and improves the plastic deformation ability of the structure. References | Related Articles | Metrics

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Analysis on joint distribution of wind speed and direction of wind power plant in Northwest China based on long-term measured data LI Wan-run, ZHANG Guang-li, LI Lin, DU Yong-feng 2022, 48 (3):  115-124.  Abstract ( 316 )   PDF (8642KB) ( 321 )   Save In order to study the structural response of wind power generation structure under wind load more accurately, based on long-term field-measurement data in six regions of Gansu Province from 1981 to 2017 provided by Gansu Meteorological Bureau, the extreme value samples were selected by the extreme value sampling method using one day as the basic interval, and the joint distribution of wind speed and direction in each region was obtained through statistical analysis. Based on the linearization of Gumbel, Frechet and Weibull distribution functions, the least square method was used to fit the parameters of each distribution function. The parameters of each distribution function are fitted by the least square method, and the extreme wind speed with return periods of 10, 50 and 100 years in each region is calculated according to the parameter fitting results, and compared with the recommended value of the maximum basic wind speed standard in each region. The results show that the basic wind speed considering the influence of wind speed and direction probability is more in line with the actual situation, and the value of the maximum basic wind speed recommended by the code is conservative. References | Related Articles | Metrics

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Two-stage optimization method for bearing layout of isolated structures DANG Yu, ZHAO Gen-xiong, TIAN Hong-tu 2022, 48 (3):  125-132.  Abstract ( 268 )   PDF (859KB) ( 284 )   Save A two-stage optimization method is proposed to determine the optimum layout of isolation bearings. In the first stage, genetic optimization is performed to identify the parameters of the isolated layer. In the second stage, a linear programming method is adopted to optimize the layout of isolators. This study constructs a hybrid framework in which the nonlinear time history analyses are conducted using the software SAP2000 and the optimization is accomplished by MATLAB. The former provides the responses of isolated buildings, and the latter calculates the associated objective function and identifies the optimal design. The proposed method is demonstrated in a typical isolated building in China. Compared with the original design scheme, the horizontal damping coefficient of the isolation bearing arrangement scheme determined by this method can be reduced by about 12%, the maximum displacement of bearing can be reduced by about 21%, and the cost of the isolation layer can be increased by about 14%. It shows that the optimization result of this method is reliable and can effectively improve the design quality and efficiency of isolation engineering. References | Related Articles | Metrics

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Field measurement and finite element analysis of foundation reinforcement for a high-rise building in soft soil area SUN Kang-cai 2022, 48 (3):  133-139.  Abstract ( 236 )   PDF (2644KB) ( 252 )   Save Improper foundation treatment, unreasonable foundation design or other reasons will cause uneven settlement of a building, which will affect normal usage of the building. Taking a high-rise building with uneven settlement as an example, the two foundation reinforcement processes experienced by the building were introduced in detail. Combined with on-site monitoring and numerical simulation method, the effect of the two reinforcements were analyzed, and the development trend of settlement in the next two years was predicted. The results show the uneven stratum and the negative friction of the pile foundation caused by the soil consolidation are the reasons for the uneven settlement of the building; the excess pore water pressure is basically dissipated three years after superstructure construction. In foundation reinforcement, a reasonable bearing layer should be selected for foundation piles, for example, if the pile length is short, even if there are many piles, it can not function well. There is a hysteresis effect for the foundation reinforcement, since the construction of the reinforced pile has a disturbance to the soil, the settlement of a building will not stop immediately, but tend to be stable after the disturbance stopped. Settlement joints are of great significance to the control of large-scale uneven settlement, so special attention should be paid to them in the design. References | Related Articles | Metrics

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Study on calculation method of effect of subway foundation pit dewatering on surrounding environment in northwest China CAI Xiao-ling, YU Li, LI Ji-ming 2022, 48 (3):  140-145.  Abstract ( 156 )   PDF (757KB) ( 210 )   Save In order to ensure the smooth construction of subway in northwest China, the deep foundation pit dewatering projects of subway stations in Xi’an and Lanzhou are studied and analyzed, and the additional settlement estimation formula for the ground settlement deformation around the foundation pit caused by the deep foundation pit dewatering of the subway station is summarized and the seepage is considered. The settlement calculation formula under the action of force, combined with the actual project, compares the two theoretical calculation results with the measured settlement results. The results show that the calculation results of the additional settlement estimation formula are conservative compared to the actual measured settlement results, and empirical coefficients should be brought in to make the results to match the actual situation better. The accuracy of settlement calculation formula considering the seepage force is greatly improved in comparison with the additional settlement estimation formula, and it is closer to the measured settlement results, which can be used as a calculation formula for the impact of dewatering on the surrounding environment of subway foundation pits in the northwestern region. References | Related Articles | Metrics

Scientific

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N-projective modules relative to a fully invariant submodule F of module N WANG Yong-duo, DU Xiao-wei 2022, 48 (3):  146-153.  Abstract ( 177 )   PDF (301KB) ( 216 )   Save The concepts of N-projective modules relative to a fully invariant submodule F of module N and R-projective modules relative to an ideal I are introduced.Basic properties of these modules are studied, some conclusions of N-projective modules,τ-N-projective modulesand Rad-N-projective modules are unified. References | Related Articles | Metrics

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The spectra of distance related matrices of some subdivision join graphs of regular graphs LU Peng-li, LUAN Rui, LIU Wen-zhi 2022, 48 (3):  154-162.  Abstract ( 115 )   PDF (408KB) ( 124 )   Save By using the relationship of the incidence matrix and the adjacency matrices of a regular graph and its line graph, the spectra of the distance matrices, distance Laplacian matrices and distance signless Laplacian matrices of the subdivision-edge join, subdivision-vertex join, subdivision-(vertex-edge) join of two regular graphs are proved to be presented by the adjacency spectra of their original graphs. References | Related Articles | Metrics

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Super-biderivations and super-commuting maps on super Lie algebras Alg(K3,ω3) HUANG Zhong-xian 2022, 48 (3):  163-168.  Abstract ( 138 )   PDF (401KB) ( 192 )   Save Using the basic properties of super double derivations, the super-skewsymmetric super-biderivations of the super Lie algebras Alg(K3,ω3) are determined, and it is proved that all super-biderivations of the Alg(K3,ω3) are inner derivations. Furthermore, it is obtained that the linear super-commuting map of the Alg(K3,ω3) is standard. References | Related Articles | Metrics

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Dual τ-Rickart modules LI Yu-yan, HE Dong-lin 2022, 48 (3):  169-172.  Abstract ( 159 )   PDF (346KB) ( 178 )   Save Let τ=(T,F) be a hereditary torsion theory, the concept of dual τ-Rickart module is introduced. A module M is called dual τ-Rickart if π－1τ(Im ψ－ ) =Im ψ+τ(M) is a direct summand of M for every ψ∈End(M).Properties of dual τ-Rickart module are studied, some equivalent characterizations to be dual τ-Rickart are given. Moreover, it is proved that M isτ-Rickart and M/(τ(M)) has C2 condition if and only if M is dual τ-Rickart and M/(τ(M)) has D2 condition. References | Related Articles | Metrics