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28 June 2025, Volume 51 Issue 3 Previous Issue    Next Issue

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Materials Science and Engineering

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Evolution of non-dendrite microstructure of Mg-xZn-0.3La-0.3Si magnesium alloy HUANG Xiao-feng, HE Guang-liang, CHEN Xuan-yu ZHANG Xin-tao, TAO Wei, HE Dan-dan 2025, 51 (3):  1-8.  Abstract ( 194 )   PDF (5598KB) ( 90 )   Save The Mg-9Zn-0.3La-0.3Si alloy was subjected to isothermal heat treatment at different temperatures and different durations, and the influence of holding temperature and holding time on the evolution of non-dendritic structure in Mg-9Zn-0.3La-0.3Si alloy were studied. The formation mechanism of non-dendritic grains was also analyzed. The experimental results showed that isothermal heat treatment can transform the as-cast dendritic structure of Mg-9Zn-0.3La-0.3Si alloy into spherical non-dendritic grain structure. The ideal non-dendritic structure is obtained at a holding temperature of 585 ℃ for 30 minutes, with a solid-phase fraction, shape factor, and average grain size of 74%, 1.32, and 63.59 μm, respectively. With the extension of holding time or the increase of holding temperature, the average size and shape factor of non-dendritic grains first decrease and then increase, while the solid-phase fraction of non-dendritic structure continues to decrease. The evolution of non-dendritic structure mainly includes three stages: initial coarsening, dendrite melting and grain spheroidization, grain coalescence and maturation. References | Related Articles | Metrics

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First principles simulation of thermoelectric transport characteristics of phosphorene XU Yi-fan, LIU Yuan-chao, JIANG Xu-hao 2025, 51 (3):  9-14.  Abstract ( 103 )   PDF (3428KB) ( 43 )   Save Phosphorene is a two-dimensional layered material which have special structure and excellent physical properties. The phosphorene is a kind of medium temperature thermoelectric material with application prospect. Based on the density functional theory, the thermoelectric transport properties of the phosphorene were simulated, which were given the anisotropy thermoelectric transport mechanism and the method of regulating thermoelectric properties in this paper. The results showed that the phosphorene has a size effect and an adjustable band gap. By adjusting the feature size, phonon scattering can be increased and thermal conductivity can be reduced. Phosphorene has anisotropy and excellent thermal transport performance in zigzag direction (ZZ direction), and its thermal conductivity decreases with increasing temperature. The armchair direction (AC direction) has excellent electrical transport performance, and the ZT values increases with the increase of temperature. At the thermal transport performance, the thermal conductivity in ZZ direction is κZZ=142.7 W/mK at 300 K, and the AC direction is κAC= 24.9 W/mK. At 800 K, κZZ=44.45 W/mK,κAC=9.50 W/mK. In the thermoelectric performance, ZT value in AC direction is 0.21 and ZT value in ZZ direction is 0.01 at 300 K. At 800 K, the ZT value in the AC direction is 0.71, and the ZT value in the ZZ direction is 0.05. References | Related Articles | Metrics

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3D printed porous TiO2 photocatalytic degradation sieve and photocatalytic performance LI Cui-xia, YUAN Bo, WANG An-hang, ZHANG Xin 2025, 51 (3):  15-23.  Abstract ( 110 )   PDF (4048KB) ( 21 )   Save A technique for fabricating a porous TiO2 photocatalytic degradation screen using direct ink writing (DIW) 3D printing method had been developed. The influence of P25 powder, TiO2 precursor sol and polyvinyl alcohol (PVA) content on the molding performance of the printing slurry had been clarified. Further studies were conducted on the phase composition, microscopic morphology, band structure, and carrier lifetime of the degradation screen, and its photocatalytic degradation performance and cyclic stability under simulated natural light for tetracycline hydrochloride (TC) were determined. The results showed that the TiO2 precursor sol can disperse P25 particles and stabilize the slurry, while the addition of PVA further improves the rheological properties of the slurry. When 9 g of P25 powder is mixed with 10 mL of TiO2 precursor slurry and 1 mL of 7% PVA solution, the printing slurry with the best molding performance is obtained. The degradable screen structure made by the prepared material is intact, without collapse and crack. After thermal treatment, the TiO2 precursor dispersion is converted into small-sized TiO2 particles, which fill the voids between P25 particles and enhance the mechanical strength. Meanwhile, PVA serves as a pore former to greatly enrich the pore structure of the degradable screen. TiO2 photocatalytic degradation screen exhibits excellent photocatalytic performance and cyclic stability towards TC, with a degradation rate of 98.4% within 140 minutes and a degradation rate of 96.0% after five cycles. References | Related Articles | Metrics

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Effect of steel slag single addition and dual addition on the properties of magnesium oxychloride cement QIAO Hong-xia, WANG Jin-pen, SHANG Ming-gang, HAN Yue-hui 2025, 51 (3):  24-31.  Abstract ( 114 )   PDF (6415KB) ( 137 )   Save In order to expand the application of steel slag in different cementitious materials, the effects of single addition of steel slag and dual addition of steel slag and fly ash on the flowability, heat of hydration, compressive strength, and water resistance of magnesium oxychloride (MOC) cements were investigated. Microscopic methods such as X-ray diffraction (XRD), low-field nuclear magnetic resonance (LF-NMR) and scanning electron microscopy (SEM) were used to characterize the hydration products and microscopic morphology.The results showed that theaddition of steel slag as supplementary cementitious materials to MOC can improve the working performance of MOC. When the dosage of steel slag is 10%, the effect on the compressive strength of MOC at all ages is not obvious, and the water resistance of MOC is improved. The compressive strength and water resistance of MOC decrease significantly when the dosage is greater than 10%. There is a hydration superposition effect of steel slag and fly ash in MOC, and when the dual addition ratio is 1∶1, the specimen has the highest total hydration exotherm, the best water resistance, and the softening coefficient is increased by 0.38. References | Related Articles | Metrics

Mechanical Engineering and Power Engineering

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Optimization of cooling channel structure of air-cooled oil-cooled oil-free scroll compressor based on RBF PENG Bin, DOU Wang-hong, NIU Ke 2025, 51 (3):  32-40.  Abstract ( 201 )   PDF (5518KB) ( 120 )   Save In order to improve the uniformity of air supply in the cooling channel of the air-cooled oil-free scroll compressor, reduce the energy loss, and improve the heat dissipation effect of the dynamic and static scroll disk, the structure of the cooling channel is optimized through numerical simulation and multi-objective optimization. The cooling channel section, transition form, and the shape and number of deflectors are used as the research objects for numerical simulation. The radial basis neural network is used to construct an approximate model, and the NSGA-Ⅱ algorithm is used to carry out multi-objective optimization to select structural parameters, and then the final model of the cooling channel is determined. The relationship between inlet velocity and flow field was studied. The results show that, after optimization, the relative standard deviation of outlet velocity was reduced by 30.73%, the relative standard deviation of center section velocity was reduced by 50.17%, and the inlet and outlet pressure drop was reduced by 87.16%, which significantly improved the uniformity of air supply and reduced energy loss. While the flow field uniformity was relatively insensitive to variations in inlet velocity, the pressure drop exhibited sharp changes. References | Related Articles | Metrics

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Experimental study of a new flow channel enhanced air gap membranedistillation WU Jiang-bo, MA Feng, DU Xiao-ze, GUO Xin-rui 2025, 51 (3):  41-47.  Abstract ( 97 )   PDF (4049KB) ( 74 )   Save Membrane distillation is very promising in the field of wastewater treatment as a means of water recovery method driven by industrial low-temperature waste heat. A variety of new membrane modules with different sizes of semi-cylindrical baffles were constructed by incorporating different sizes of hot liquid flow channels in the air-gap membrane modules. A test rig was set up to systematically investigate the membrane flux and thermal efficiency of the new modules under different conditions of hot and cold liquid inlet temperatures and flow. The results show that the hot feed inlet temperature and flow as well as the cold feed flow are positively correlated with membrane flux, while the cold feed inlet temperature is negatively correlated with membrane flux. Additionally, the hot feed inlet temperature is positively correlated with thermal efficiency. In the new modules, as the size of the semi-cylindrical baffle in the hot channel increases, the membrane flux increases by 4.3%, 6.4%, and 8.7%, respectively, and the thermal efficiency increases by 2.4%, 3.4%, and 4.8%, respectively, compared with the module without the baffle. The results indicate that this new module configuration has the advantages of high flux and high thermal efficiency, providing an optimized basis for the development of high-efficiency air-gap membrane distillation modules. References | Related Articles | Metrics

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Optimization design of wheel reducer transmission system based on particle swarm hybridization algorithm WEI Yong-qiao, ZHANG Zhen-ning, LIU Yong-ping, YAN Chang-feng, XIE He-ping 2025, 51 (3):  48-54.  Abstract ( 155 )   PDF (2342KB) ( 197 )   Save Aiming at the problems of heavy weight and low efficiency in the wheel reducer of the mining electric wheel dump truck, the multi-objective optimization design of the wheel reducer drive system is carried out on the premise of satisfying the smooth operation of the wheel reducer. The particle swarm optimization (GA-PSO) hybrid algorithm with the genetic idea is adopted. The volume and transmission efficiency of planetary gear trains are taken as the optimization objectives, which is constrained by 8 constraints such as assembly, and the mathematical model is established and solved accordingly. By comparing and analyzing the original model and the optimized model, it is shown that the transmission efficiency of the wheel reducer after optimization is increased by 0.79% and its volume is reduced by 11.36%. The load spectrum is set according to the actual working conditions, and the life of each gear after optimization is analyzed. The results show that the damage ratio of the secondary sun gear is the largest which is 9.63%, with a total service life reaching 756 400 h. The service life of other gears meets the design requirements. References | Related Articles | Metrics

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Fault recognition of rolling bearing based on multi scale atrous convolution-convolutional neural network WANG Xiao-hu, ZHAO Rong-zhen, DENG Lin-feng, ZHENG Yu-qiao 2025, 51 (3):  55-63.  Abstract ( 108 )   PDF (4047KB) ( 37 )   Save Aiming at the problems of low intelligent diagnosis efficiency of rolling bearings due to the excessive number of parameters of existing convolutional neural network models and the limited recognition accuracy due to the number of training samples, a rolling bearing fault recognition method based on multi-scale atrous convolution-convolutional neural network (MSAC-CNN) was proposed. In this method, a large atrous convolution kernel and a standard convolution kernel are used in the input layer of the model to extract the multi-scale sensitive features of one-dimensional vibration signals. Then, the sensitive features extracted in the input layer were further extracted by using the 1×1 and 3×1 small convolution kernel and the 2×1 maximum pooling operation. Finally, the fully connected layer in the traditional convolutional neural network is replaced by the global average pooling layer. The experimental verification results with bearing fault data from Western Reserve University and our laboratory show that the proposed method has good generalization performance and performs the task of fault identification with fewer training samples. Moreover, it can accurately identify weak bearing faults under certain noise interference. References | Related Articles | Metrics

Chemical Industry and Light Industry

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Study on F- modification and Na+ storage capacity of negative battery electrode material Ti3C2/MoS2 DONG Ming-hui, ZHAGN Yan, SHEN Shi-ying, LIU Na, ZHAO Shu-ping 2025, 51 (3):  64-72.  Abstract ( 91 )   PDF (4152KB) ( 23 )   Save The ion insertion positions provided by graphene for Na+ batteries are very limited, resulting in low electrical activity and capacities of the battery, which affects the charging and discharging behaviors. In order to search for a new kind of negative electrode material for Na+ batteries, three different adsorption sites of F-groups were constructed, namely the top of Ti1 (Ⅰ-Ti3C2F2), the top of C (Ⅱ-Ti3C2F2), and the top of Ti2 (Ⅲ-Ti3C2F2). The stability and Na+ storage capacity of the three configurations were also calculated. The calculation results indicate that the F-functional group can reduce the formation energy, enhance structural stability, and increase the atomic layer spacing at the interface between the two heterojunctions, which is beneficial for the insertion and detachment of Na+. For Ti3C2 and three Ti3C2F2 structures, the most stable adsorption sites for Na+ are at the top of Ti1 atom, S atom, and Ti2 atom, respectively. As the dielectric constant increases, the adsorption energy of Na+ also increases, especially for I-Ti3C2F2 and Ⅲ-Ti3C2F2.For Ⅰ-Ti3C2F2 and Ⅲ-Ti3C2F2, the diffusion barrier can be reduced due to the electrolyte, which is beneficial for rapid charging and discharging. The OCV curves for Ⅰ-Ti3C2F2 and Ⅲ-Ti3C2F2 show a gradual decline and a high open-circuit voltage, making them ideal candidates for energy storage materials. References | Related Articles | Metrics

Automation Technique and Computer Technology

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Distributed coordination control of microgrid system based on event-triggered consensus algorithm WU Li-zhen, JIANG Wen-dong, CHEN Wei, HAO Xiao-hong 2025, 51 (3):  73-80.  Abstract ( 171 )   PDF (3079KB) ( 37 )   Save There are some problems such as communication delay, high sampling rate, and frequent controller updates in the networked microgrid system, the paper proposes a distributed coordination control method for a microgrid system based on event-triggered consensus algorithm, which combines the event-triggered method with the consensus algorithm. The distributed generation unit is an intelligent node in the distributed sparse network, and the state observer is designed using the consensus algorithm, and designs event-triggered conditions based on the state information of smart nodes. When an event is triggered, the observer transmits the actual state value to the controller, while also sharing the information to the neighbor controller. This control method requires the distributed controller to communicate when the event is triggered, effectively reducing the number of controller updates and minimizing thesystem’s requirements for network bandwidth. The stability of the control system was analyzed by the Lyapunov function. Finally, simulation platform is built by Matlab/Simulink simulation software to validate the proposed control method, demonstrating its robustness dynamic performance under communication delay. References | Related Articles | Metrics

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An elliptical extended target tracking method based on variational Bayesian filtering under abnormal noise conditions CHEN Hui, WANG Li, ZHANG Tian-you, ZHANG Guang-hua 2025, 51 (3):  81-88.  Abstract ( 128 )   PDF (2256KB) ( 65 )   Save Aiming at the problem of ellipse extended target tracking under thick-tailed noise, a robust Student’s t extended target method is proposed based on variational Bayesian inference. Firstly, the Student’s t distribution is used to model the non-Gaussian thick-tailed process and measurement noise. The K-L divergence is adopted to find the Gaussian distribution closest to the Student’s t distribution, allowing the posterior probability densityto be approximated as a Gaussian distribution. Secondly, a random positive definite matrix following an inverse Wishart distribution is applied to describe the size and direction of the ellipse shape. Based on the hierarchical Gaussian state space model and variational Bayesian method, the unknown scale matrix and auxiliary random variables are derived to jointly derive the motion state and shape expansion state of the target recursively. Finally, simulation experimental results verify the proposed algorithm efficiency and robustness. References | Related Articles | Metrics

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Feature selection for simultaneous optimization of SVM based on improved sooty tern algorithm ZHAO Xiao-qiang, XIAN Wen-xia 2025, 51 (3):  89-98.  Abstract ( 109 )   PDF (4255KB) ( 64 )   Save To address the significant impact of features selection and parameter optimization on classification accuracy in support vector machine (SVM), a feature selection algorithm based on the improved sootytern algorithm to optimize SVM synchronously is proposed. Firstly, the Tent chaotic map is used to initialize the sooty tern population to increase the diversity of the population. On this basis, cosine adaptation and simulated annealing algorithm are introduced to avoid the defect of the sooty tern algorithm falling into local optimality, enhance the global search ability of the algorithm, and improve the convergence accuracy. Secondly, the improved algorithm is combined with feature selection and SVM, and the parameters of binary feature selection and SVM are optimized simultaneously. Finally, feature selection simulation comparison experiments are carried out on 10 standard datasets. Compared to the original and other optimization algorithms, the proposed algorithm can effectively reduce the data dimension and improve the classification accuracy. References | Related Articles | Metrics

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Chinese authorship identification based on fine-grained word feature ZHAO Hong, ZHANG Chen-peng, WANG Ao-long, ZHANGYang 2025, 51 (3):  99-106.  Abstract ( 109 )   PDF (2308KB) ( 25 )   Save Most existing authorship identification models are primarily designed for English texts. However, due to the differences between Chinese and English in grammar and language elements, the English authorship identification models have large deviations when applied to Chinese text. To solve the problem of Chinese author identification, a model adapted to Chinese features is proposed, termed the Chinese author recognition model with fine-grained word features. The model uses parallel convolution to extract fine-grained features from 1 to 4 characters and combines with an attention mechanism for weight assignment. Finally, Chinese authorship identification is obtained by the classifier. The experimental results show that the accuracy of this model is average improved by 2.09%, 7.2%, and 6.71% on three Chinese author identification datasets compared with the baseline models of BERT, TextCNN, and RNN, separately. Therefore, this model has a high value in reality. References | Related Articles | Metrics

Architectural Sciences

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Analysis ofmechanical behavior of bucklingrestrained brace with ductile casting connectors under cyclic loadings YIN Zhan-zhong, YANG Yong-an, ZHANG Su-feng 2025, 51 (3):  107-112.  Abstract ( 98 )   PDF (4774KB) ( 32 )   Save When the braces in the centrally braced steel frame are connected with the beam-column of the frame, the triaxial stress field is easy to occur in the joint area, which leads to brittle failure. To address this issue, ductile casting connectors are used instead of nodal plates and beam-column connections and conducts numerical simulations to analyze the mechanical performance of buckling-restrained braces (BRBs) with ductile cast connections under cyclic loading. The failure mode, hysteretic curve, and energy dissipation of of these BRBs were analyzed. Additionally, the effects of the length of energy-dissipating section, energy dissipation plate, and stiffener of ductile castings on the performance of BRBs are analyzed. The results indicate that, under loading, the energy-dissipating segment of the cast connection is the first to yield.. With the increase of load, the supporting core tube enters into the plastic stage and consume energy together with the casting connector. The hysteretic curves of BRBs with ductile casting connector exhibit a stable and symmetrical shape, demonstrating excellent energy dissipation capacity. References | Related Articles | Metrics

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Effect of cross fracture angle on mechanical properties and damage propagation failure of sandstone CHEN Xiang, XIAO Tao-li, SHE Hai-cheng 2025, 51 (3):  113-118.  Abstract ( 97 )   PDF (5095KB) ( 32 )   Save Cross crack, as one of the common forms of fractured rock mass, the overlapping geometry properties affect the expansion damage of rock mass and the catastrophe mechanism. Taking rock samples containing a single group of cross fractures as the research object, the mechanical properties and propagation failure laws of rock samples affected by the dip angles of primary and secondary fractures are emphatically discussed. The results show that: when the inclination angle of the primary fracture is less than or equal to 45°, the horizontal projection length of the primary fracture is larger than that of the secondary fracture, and the inclination angle of the primary fracture has a great influence on the peak strength and elastic modulus of the rock sample. When the inclination angle of the primary fracture is greater than 45°, the horizontal projection length of the secondary fracture is larger, and the inclination angle of the secondary fracture has a great influence on the peak strength and elastic modulus of the rock sample.The macroscopic crack propagation on the surface of rock samples is mainly characterized by the cracks at the primary crack tip and the secondary crack tip, while the far-field cracks and surface spalling are less.The failure mode of rock samples is controlled by the horizontal projection length of the primary and secondary fractures, that is, when the projection length of the primary fracture is larger than the secondary fracture, the failure is controlled by the primary fracture. Otherwise, it is controlled by the secondary fracture. References | Related Articles | Metrics

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Bond slip constitutive model of circular steel tube and high-strength pebble mechanism sand concrete GUAN Min-sheng, ZHENG Zong-ying, ZHANG Kun, DU Hong-biao 2025, 51 (3):  119-126.  Abstract ( 82 )   PDF (996KB) ( 5 )   Save In order to study the interfacial bond and slid performance of high-strength pebble mechanism sand concrete with circular steel tube, pull-out tests were conducted on 27 short column specimens of high-strength pebble mechanism sand concrete and circular steel tubes to obtain load slip curve parameters. The development stages and mechanisms of bond and slid of the specimens were analyzed, and the influence of different position distributions on bond and slid performance was investigated. A bond stress slip constitutive model considering position changes was derived. The results show that the bond and slid of high-strength pebble mechanism sand concrete with round steel tubes go through four stages: bond, slid, frictional resistance, and post slid. The order of slid at different positions of the specimen is different. The applicability of the proposed constitutive model for bond and slid of circular steel tube and high-strength pebble mechanism sand concrete in the experimental specimens introduced in this paper was verified. Based on the above constitutive model, the changes in local bond strength and slid values of the specimens were reflected by introducing a position function. A bond and slid constitutive model considering position changes was proposed, which can more fully reflect the local bond and slid laws and mechanisms. References | Related Articles | Metrics

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Experimental study on shear mechanical properties of cement-soil-concrete interface under different normal pressure loading modes LIU Hong-yuan, ZHU Ming-xing, LI Xiao-juan, PENG Shun-kai, YIN Qian 2025, 51 (3):  127-133.  Abstract ( 99 )   PDF (6198KB) ( 12 )   Save The current research on cement-soil mainly focuses on its strength characteristics, while studies on the shearing mechanical properties of the cement-soil-structure interface remain relatively limited, which will restrict the promotion and application of cement-soil reinforcement technology in large-scale block foundations under horizontal loading. Thus, based on the self-developed large-scale interface shearing equipment, a series of shear tests and mechanistic studies on the cement-soil-concrete interface under repeated loading-unloading of variable normal stress mode and continuous normal stress loading mode have been performed, respectively. Moreover, based on the Mohr-Coulomb criterion, the formula for the minimum friction coefficient of the interface was derived.The results show that the solidification effect of cement-soil can significantly enhance the interface shear mechanical properties. The friction coefficient of the cement-soil-concrete interface gradually increases with the increase of curing time. The sliding shear plane can be remolded under pre-loaded normal pressure. As a result, the interfacial shear characteristics of a single specimen under cyclic loading-unloading modes are approximately equivalent to that of multiple identical specimens separately loaded. The shear behavior of the cement-soil-concrete interface under continuous normal stress loading will become weaker. Thus, in practical engineering, the shear performance of interfaces under such loading conditions should not be overestimated. References | Related Articles | Metrics

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Internal force optimization and experiment of variable parameter bridge based on energy methods YANG Guo-jun, LI Xi-mei, ZHAO Hang, LYU Ming-hang 2025, 51 (3):  134-142.  Abstract ( 150 )   PDF (5378KB) ( 243 )   Save In order to determine the optimal internal force of variable parameter bridge, the model in the 14th National College Students’ structural design competition is theoretically analyzed and optimized, and the single objective linear optimization design mathematical model and the simplified calculation model of bridge structure are established. The exhaustive algorithm and Visual C++ programming is used for optimization calculation, including the optimization of bridge main span and the selection of load value at loading point, the static analysis, structural optimization design and actual model test are carried out. The numerical calculation formula is deduced, and the random optimization method of bridge span, load loading position and other parameters aiming at the minimum bending strain energy is proposed. The minimum values of vertical displacement and internal force of the structure under load are sought, obtaining the load layout. The span of the main span is inversely calculated. Then the finite element software is used for modeling analysis and experimental verification. Testing confirms that the load distribution mode 1 is the optimal load distribution, withP1-P8 values set to 40 N, 50 N, 120 N, 130 N, 60 N, 70 N, 80 N and 90 N. References | Related Articles | Metrics

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Study on the closing effect and influencing factors of double-row piles HE Qing-wen 2025, 51 (3):  143-149.  Abstract ( 108 )   PDF (2538KB) ( 34 )   Save Taking a foundationpit ina highway project as anexample, a numerical model was established using finite element software. Based on the verification of the model’s correctness through on-site monitoring results and improved formulas, the deformation of the foundation pit under two working conditions of double row pile closure and single row pile closure was compared and analyzed. The influence of pile diameter, row spacing, and pile spacing on the stability of double row pile support structure through variable analysis method were studied and range values were provided. The results show that the stiffness and stability of the double row pile support structure are higher than the single row pile support structure, and the closing effect is also better. The calculated values obtained by improving the formulas have a similar growth trend to the finite element simulation values, which verifies the correctness of the formula and model. The pile diameter, row spacing, and pile spacing can affect the deformation of the double row pile support structure. When the pile diameter is 0.8~1.1 m, the row spacing is 2~3.5 times the pile diameter, and the pile spacing is 2~4 times the pile diameter, the best effect of the double row pile support structure can be achieved. References | Related Articles | Metrics

Scientific

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Enumerative problem on the 2-G-Motzkin paths YANG Sheng-liang, ZHANG Yu-yuan 2025, 51 (3):  150-155.  Abstract ( 98 )   PDF (524KB) ( 34 )   Save The concept of the 2-G-Motzkin path is introduced. By using the symbolic method, the Lagrange inversion formula, and the Riordan array, some enumerative problems on the 2-G-Motzkin paths are studied and the corresponding generating functions and computing formulas are given. References | Related Articles | Metrics

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Maximal (completely) isolated subsemigroups of semigroup BI(n,r) LUO Yong-gui, XIAO Jian, YU Jiang-hui 2025, 51 (3):  156-160.  Abstract ( 97 )   PDF (504KB) ( 29 )   Save Let In and Sn be symmetric inverse semigroup and symmetric group on the finite set Xn={1,2,…,n}, respectively. For 0≤r≤n－1, put I(n,r)={α∈In:|im(α)|≤r}, then the I(n,r) is a two-sided ideals of symmetric inverse semigroup In. Denote Bn=〈δn〉, where there is i δn=n+1－i for any i∈Xn, saying that Bn is a circle group on Xn. By analyzing the Green’s relation and generative relation of the semigroup BI(n,r)=I(n,r)∪Bn, the complete classification of the (completely) isolated subsemigroups of BI(n,r) is obtained. Furthermore, the coincide of maximal isolated subsemigroups and maximal completely isolated subsemigroups of BI(n,r) be proved. References | Related Articles | Metrics

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Conformal-projectively equivalence of statistical manifolds and its affine immersion XU Xiao-li, WANG Yu, QIN Hua-jun 2025, 51 (3):  161-166.  Abstract ( 100 )   PDF (435KB) ( 18 )   Save Statistical manifolds with a flat structure or a conformal projective flat structure are the main objects studied in information geometry. The conformal projective equivalence of statistical manifolds is investigated, and several properties are obtained. Meanwhile, relative affine immersions with codimension 2 are studied, and the relationships between statistical structures derived from different immersion methods are obtained. References | Related Articles | Metrics

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Core-monotonicity characterizations for nonnegative matrices LIN Lin, ZHONG Jin 2025, 51 (3):  167-172.  Abstract ( 87 )   PDF (567KB) ( 23 )   Save Characterizations for the core-monotonicity of nonnegative matrices are studied. A sufficient and necessary condition for core-monotonicity of nonnegative matrices is presented by nonnegative full-rank decomposition, and the representation of the core inverse is also given when it is nonnegative. It is shown by some numerical examples that the nonnegativity of the core inverse and the Moore-Penrose is not equivalent to the group inverse of nonnegative matrices. Furthermore, a sufficient and necessary condition for the core-monotonicity of nonnegative matrices is given by using the Moore-Penrose inverse and group inverse. Additionally, a sufficient and necessary condition for the core-monotonicity of real matrices is presented, which extends the results of Collatz. References | Related Articles | Metrics