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Liu Zi’ang, Yang Lining, Yang Guang, Liu Guang
2026,47(4):343-352, DOI: 10.7535/hbkd.2026yx04001
Abstract:
To address the issues of insufficient lubrication retention capacity and wear resistance of polycarbonate-polyurethane(PCU) artificial meniscus, this study utilized the fused deposition modeling(FDM) process to fabricate PCU specimens with periodic grid-like blind hole structures. The key size parameters such as the width and depth of the microholes were systematically controlled. Through wetting tests and repetitive friction experiments simulating the joint environment, the influence laws of microstructure geometric features on the surface lubrication behavior, lubricant retention characteristics, and friction and wear mechanisms of the specimens were systematically explored. The results show that increasing the depth of the microholes can enhance the lubricant storage capacity, but excessive depth would lead to a decrease in the penetration rate of the lubricant and a weakening of the bearing capacity of the hole wall structure. Increasing the width of the microholes can effectively promote the penetration of the lubricant, expand the coverage area of the liquid film, and thereby improve the interface lubrication effect. Reasonably matching the depth and width parameters of the microholes can ensure the storage capacity of the lubricant while achieving timely replenishment of the lubricant, significantly reducing the friction coefficient and alleviating the wear degree. Among them, the parameter combination of hole depth of 1.0 mm and hole width of 0.6~0.8 mm can achieve a dynamic balance between lubricant storage and replenishment, and achieve the optimal matching among the storage capacity, supply efficiency and structural integrity. This research provides a reliable experimental basis and theoretical reference for the surface functionalization design and improvement of the frictional properties of PCU artificial meniscus.
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Xi Lele, Xu Jun, Li Zhijie, Hua Changchun
2026,47(4):353-363, DOI: 10.7535/hbkd.2026yx04002
Abstract:
To address the core challenges in multi-UAV collaborative path planning-balancing computational efficiency and optimization accuracy for large-scale tasks, and coupling real-time response with constraint adaptation in complex scenarios- an improved GPU(graphics processing unit)-accelerated artificial hummingbird algorithm(AHA-GPU) was proposed. Firstly, the study constructed a multi-objective mathematical model integrating path length, task balance, and obstacle avoidance cost, with clear constraints including coverage integrity, UAV dynamics, collision and obstacle avoidance. Secondly, a hybrid exploration strategy combining territorial foraging, migratory foraging, and directed foraging was designed, and a constraint compensation mechanism was introduced to achieve synergy between obstacle avoidance and optimization. Finally, a CPU+GPU heterogeneous parallel framework based on CUDA(compute unified device architecture) was built, in order to improve computational efficiency through thread block optimization and shared memory scheduling. Simulation and real-machine experimental results show that the AHA-GPU algorithm achieves a 10~48x speedup in computation and reduces the total path length by 7%~13% compared with traditional CPU-based algorithms. In obstacle-containing environments, the algorithm reaches a 97.05% area coverage rate and an obstacle avoidance cost of 4.709 0. In 5 m×5 m indoor real-machine experiments, the obstacle avoidance success rate hits 100%. All indicators rank among the top, ensuring excellent solution quality while significantly improving performance. This algorithm effectively breaks through the multi-dimensional contradiction of "efficiency-accuracy-safety" in large-scale complex tasks, providing an efficient and reliable path planning solution for multi-UAV collaborative operations in complex environments.
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Zhang Lijun, Chen Shuo, Li Zhijie, Liu Na, Wang Yan, Lu Jiyong, Ji Yude
2026,47(4):364-374, DOI: 10.7535/hbkd.2026yx04003
Abstract:
To achieve encirclement control of non-cooperative targets by leader agents, a cooperative encirclement strategy integrating prescribed-time convergence and prescribed performance constraints was proposed. A prescribed-time geometric center estimator was designed, which enabled the leader agents to accurately estimate the geometric center of the non-cooperative target agents within a user-specified time. Building upon this, combined with the designed velocity field and prescribed performance function, an encirclement control strategy was developed. This strategy not only drove the leader agents to form a circular formation for encirclement but also ensured that the geometric center of the non-cooperative target agents moved along the desired trajectory. Based on Lyapunov stability theory, it was rigorously proven that the proposed control strategy guaranteed that the encirclement error converges within the prescribed performance function and within a prescribed time. Numerical simulations validated the effectiveness of the proposed strategy. The results demonstrate that the proposed control strategy achieves precise encirclement control within a prescribed time and guides the geometric center to follow the desired trajectory. The proposed approach not only ensures that the upper bound of the convergence time is independent of the system′s initial state but also satisfies prescribed performance constraints, providing reference for the cooperative control of multi-agent systems.
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Qiao Fangqi, Mi Cuili, Wu Zhe, Cui Haiting, Zhang Kai, Jiang Jingzhi
2026,47(4):375-386, DOI: 10.7535/hbkd.2026yx04004
Abstract:
In order to solve the problem of low temperature uniformity caused by the arrangement of traditional swirl burners in the roller hearth heat treatment furnace, an arrangement of low nitrogen burners in the roller hearth heat treatment furnace based on gas classification technology was proposed. First of all, the optimized low nitrogen burners that have been simulated were placed on the heat treatment furnace in four different arrangements. Secondly, the Ansys Fluent software system was used to simulate the influence of different arrangements of low nitrogen burners on the temperature uniformity in the heat treatment furnace. Finally, by comparing the temperature distribution cloud map and the horizontal temperature change map of the hydrogen storage tank, the optimal arrangement of the burner was determined. The results show that compared to the other three arrangements of burners in the heat treatment furnace, the horizontal positions of y=100 mm and y=700 mm are evenly arranged, and the dislocation spacing is 400 mm, which can enhance the convection, help to improve the temperature uniformity in the furnace, and also bring about the reduction of energy consumption. After designing the low nitrogen burner, a specific way is given for the arrangement of the burner in the roller hearth heat treatment furnace, providing an optimization direction for the temperature uniformity design of the roller hearth heat treatment furnace.
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Tian Xiaosong, Gao Shihao, Zhang Zijian, Wang Qunjing, Li Guoli
2026,47(4):387-396, DOI: 10.7535/hbkd.2026yx04005
Abstract:
To address the issues of low trajectory tracking accuracy and weak cooperative capability in multi-motor systems caused by strong coupling, nonlinearity, and time-varying parameters, a cooperative control strategy based on model reference adaptive control(MRAC) was proposed. Firstly, a dynamic model explicitly incorporating inter motor coupling effects was established, and an ideal reference model suitable for three degree of freedom motion was designed. Secondly, a Lyapunov adaptive law integrating coupling term compensation was derived, which theoretically ensures the global asymptotic stability of the closed loop system. Finally, simulation and platform experiment were conducted. The results show that, in three degree of freedom trajectory tracking, the steady state error of each axis is less than 0.5°, and the dynamic response time is reduced by more than 50% compared with fuzzy PID control; In the embedded implementation, the single cycle execution time of the algorithm is only 32 μs, enabling real time control at 2 kHz on a low cost processor. This strategy overcomes the application limitations of conventional MRAC in single motor systems, significantly improves the cooperative control accuracy and robustness of multi motor systems, which provides reference for high precision control of strongly coupled multi motor systems.
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Shi Yuwei, Niu Zhi, Xin Liang, Zhang Yongdi, Liu Yuxin
2026,47(4):397-406, DOI: 10.7535/hbkd.2026yx04006
Abstract:
To address the problems of large sampling errors, low efficiency, sample contamination, and poor system stability in conventional water sampling technologies, a fully automated water sampling robot was developed. The robot was consisted of a hull frame, a multi-depth sampling module, an automatic bottle filling and sealing module, a bottle storage module, and a power module. The multi-depth sampling module employed a reel-based hose deployment mechanism, a 360° rotary joint, and electromagnetic directional valves to achieve continuous multi-depth sampling and pipeline self-cleaning. The filling and sealing module utilized an impeller-driven transmission assembly as a unified power source to accomplish bottle filling, capping, and bottle switching through mechanical linkage, thereby reducing contamination risk. A four-motor vector propulsion system was adopted to improve maneuverability, while a depth sensor combined with a fuzzy PID closed-loop control algorithm enabled real-time depth regulation. Ansys was used to perform static structural analysis on the hull frame and vector steering shaft, as well as a fluid-structure coupling analysis on the impeller to verify structural strength. The results show that the maximum stress and deformation of the hull frame are 3.22×107 Pa and 0.030 mm, respectively, while those of the vector steering shaft are 3.81×106 Pa and 0.13×10-3 mm. At a flow velocity of 15 m/s, the impeller exhibits a maximum stress of 4.77×107 Pa and a maximum deformation of 0.031 mm, with a safety factor of 5.8. All components satisfy the strength requirements. The proposed robot integrates automation, mechanical linkage, and closed-loop control, effectively improving sampling efficiency and reliability and providing a technical reference for water environment monitoring in complex aquatic environments.
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Yin Ziru, Zheng Zhizhe, Zhang Meina, Zhao Xinyan, Li Yandong, Wu Xiaofei, Zhou Tao, Han Xue
2026,47(4):407-416, DOI: 10.7535/hbkd.2026yx04007
Abstract:
In order to investigate the application value of different addition levels of Rumex hanus by.（RHB）whole powder in traditional steamed bread, and solve the problem of single nutritional structure of steamed bread, the effects of different addition levels of RHB whole powder on dough characteristics and steamed bread quality were studied using texture properties and sensory quality as evaluation indicators. The flavor and nutritional properties of steamed bread were analyzed by comprehensive application of electronic tongue, headspace solid-phase microextraction-gas chromatography-mass spectrometry(HS-SPME-GC-MS), automatic amino acid analyzer and other techniques. The results show that as the addition level of RHB whole powder is increased from 0% to 10%, the specific volume and whiteness of steamed bread are significantly decreased, while the hardness is significantly increased. The taste values of saltiness and astringency are found to exhibit a gradual upward trend. When the addition level exceeds 2%, the proofing volume of dough is significantly reduced, indicating that its proofing ability and gas retention performance are inhibited. Compared with the control steamed bread, the relative content of sweet amino acids in steamed bread with 10% addition is increased by 10%, while the relative content of umami amino acids is decreased by 9%. In sensory evaluation, the highest score(84.33 points) is obtained by the group with 2% addition, while a significant reduction in sensory evaluation score is caused by excessive addition(>6%). In addition, a total of 77 volatile organic compounds are detected in the RHB whole powder-added steamed bread. Ketones and olefins are significantly enriched at low and medium addition levels(<6%). Among them, some short-chain alcohols, esters and ketones are only present in the 2% addition group, and ketones account for 17% of the total volatile compounds.Therefore,the nutritional and functional properties of steamed bread can be enhanced and its good eating quality can be maintained by moderate addition(2%~4%) of RHB whole powder, which can provide a theoretical reference for the development and application of RHB whole powder in functional staple foods.
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Liu Bin, Zhao Jianghui, Qu Ying, Ma Teng, Zhang Hongbin, Liu Qing, Cui Chunxing, Zhang Xinzhu, Dong Jiaxing, Han Ya’nan, Wei Hailong
2026,47(4):417-425, DOI: 10.7535/hbkd.2026yx04008
Abstract:
To address the issues of semantic sparsity and fuzzy topic boundaries in public-opinion comment topic recognition, a CoSENT and feature expansion-based topic recognition method(CE-TRM) was proposed. In the sentence embedding stage, CoSENT′s ranking optimization mechanism was introduced to resolve the inconsistency between training objective and inference requirements of Sentence-BERT（SBERT）. A feature expansion framework covering both the original texts and comments was constructed, and a multi-head cross-attention mechanism was used to fuse the keywords from the original texts with the comment embeddings. Dimensionality reduction was performed using PCA combined with UMAP, and topic identification was ultimately achieved through clustering and c-TF-IDF(class-based term frequency-inverse document frequency). In the experimental stage, two cases were used: the "Mercedes Queue-Cutting Incident at Xuwen Port" and the "Excessive Blood Lead Levels in a Kindergarten in Tianshui, Gansu" ， from which 21 884 and 11 822 comments were collected, respectively. The results show that in terms of the mainstream topic recognition evaluation metric C _ v coherence score, CE-TRM（CoSENT and feature expansion-based topic recognition method） improves upon SBERT-LDA and BERTopic by 19.3% and 5.6%, respectively. These findings demonstrate that CE-TRM mitigates, to a certain extent, the negative impact of short-text feature sparsity on topic recognition, improves the accuracy of public-opinion comment topic identification, and provides new technical ideas for public-opinion evolution analysis and public decision-making.
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Xing Jingxuan, Wang Chaoying, Jia Xiaomeng, Gao Hesen, Sun Qujiang, Wang Qiujun, Wang Bo
2026,47(4):426-435, DOI: 10.7535/hbkd.2026yx04009
Abstract:
To address the issues of poly(1,3-dioxolane)(PDOL)-based electrolytes for sodium metal batteries(SMBs), such as insufficient interfacial stability with high-voltage cathodes under high potentials and a narrow electrochemical stability window, a PDOL-based gel polymer electrolyte(GPE) was prepared via in-situ polymerization of 1,3-dioxolane combined with a synergistic modification strategy using sodium difluoro(oxalato) borate(NaDFOB), fluoroethylene carbonate(FEC), and succinonitrile(SN) additives. A dual-anion aggregated Na+ solvation structure was constructed using NaDFOB, and the introduction of FEC and SN additives enabled synergistic regulation of high ionic conductivity and a highly stable interface. The results indicate that the GPEs interfacial layer modified by composite additives contains inorganic fluorine-, phosphorus-, and boron-rich components, which can effectively suppress the dissolution of transition metals(TM) from the cathode. The assembled NFM111 ‖ Na battery exhibits a capacity retention of 80% after 200 cycles at 0.5 C, and still delivers a discharge specific capacity of 101.5 mA·h/g[BFQB] at a 3.0 C rate. The multi-additive modified PDOL-based electrolyte demonstrates excellent interfacial compatibility with high-voltage cathodes, inhibits sodium dendrite growth, and improves the cycling stability of the battery, providing a new strategy for the design of high-performance SMBs.
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Liang Guozhuang, Wei Yuxuan, Han Peisong, Yu Xinran, Tian Hanlei
2026,47(4):436-447, DOI: 10.7535/hbkd.2026yx04010
Abstract:
To meet the application requirements of electrolytic hydrogen production for low-voltage, high-current, and high-power-density power supplies, a parallel-type virtual 36-pulse rectifier based on an asymmetric current injection circuit(ACIC) was proposed. Firstly, an ACIC module was integrated into the DC side of a traditional 6-pulse rectifier(6-PR), and the AC input current waveform was reshaped by injecting specific compensation currents. Subsequently, pulse-wave expansion of each ACIC unit was achieved using an interphase reactor(IR), enabling equivalent 36-pulse operation at the input side. Finally, the key parameters of the ACIC unit were derived and optimized, its capacity was quantitatively evaluated, and the effectiveness and performance advantages of the designed system were verified through simulation. The results show that this scheme significantly reduces current harmonic content, yielding an approximately sinusoidal input current. The total harmonic distortion(THD) of the grid-side current decreases to 4.68%, and the system efficiency reaches 98.2%. Compared to traditional 36-pulse rectifiers, the grid-side current THD is reduced by 0.32 percentage points, and the system efficiency is improved by 3.2 percentage points. This scheme offers significant advantages in harmonic suppression and energy efficiency enhancement. Moreover, its parallel structural design provides excellent system fault tolerance and high-power scalability, offering an effective solution for electrolytic hydrogen production scenarios.
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Xiong Zhangwei, Liu Chun, Zhang Jing, Wang Yanqiong, Zhang Jiayuan, Xu Dongyu, Mu Situ, Wang Guoqiang
2026,47(4):448-460, DOI: 10.7535/hbkd.2026yx04011
Abstract:
To address the key challenges of high chemical oxygen demand (COD), intense color, and poor biodegradability commonly found in the biological effluent of actual pharmaceutical wastewater, an electrochemical-ultraviolet-ozone(EC-UV-O3) ternary coupling advanced oxidation system was developed, and its treatment performance and underlying mechanisms were systematically investigated. The performance of three individual systems (UV,O3,EC), three binary coupling systems (O3-UV, EC-UV, EC-O3), and the EC-UV-O3 ternary system were compared. The results reveal that the EC-UV-O3 system achieves the highest treatment efficiency, COD removal rate reaches 91.1% in this system, color is completely eliminated within 40 min, and the BOD5/COD ratio increases from 0.11 to 0.59, indicating a marked improvement in biodegradability. Optimization results indicate that the system achieves the best overall performance at an electric current density of 30 mA/cm2, an O3 dosage ratio of 1.0 (mO3/mCOD), an electrode spacing of 1.0 cm, and an initial pH of 7.2, balancing high pollutant removal efficiency with energy consumption. Mechanistic analyses confirm that the enhanced generation of reactive oxygen species (ROS), including ·OH and 1O2, is the primary factor driving the improved organic pollutant removal in the EC-UV-O3 system. This study provides certain data support and theoretical basis for the engineering application of the EC-UV-O3 process in the advanced treatment of actual pharmaceutical wastewater.
Volume 47,2026 Issue 4
National Young Scholar/Local Science Foundation
Mechanical, Electronics and Information Science
Food Science and Biological Science
Data Analysis and Calculation
New Energy Resources, Energy Conservation and Environmental Protection
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WANG Jianxia, LIU Menglin, XU Yunfeng, ZHANG Yan
2021,42(1):48-59, DOI: 10.7535/hbkd.2021yx01007
Abstract:
Most of the real-life networks are heterogeneous networks that contain multiple types of nodes and edges, and heterogeneous networks integrate more information and contain richer semantic information than homogeneous networks. Heterogeneous network representation learning to have powerful modeling capabilities, enables to solve the heterogeneity of heterogeneous networks effectively, and to embed the rich structure information and semantic information of heterogeneous networks into low-dimensional node representations to facilitate downstream task applications. Through sorting out and classifying the current heterogeneous network representation learning methods at home and abroad, reviewed the current research status of heterogeneous network representation learning methods, compared the characteristics of each category model , introduced the related applications of heterogeneous network representation learning, and summarized and prospected the development trend of heterogeneous network representation learning methods. It is proposed that in-depth discussion can be carried out in the following aspects in future: First, avoid predefined meta-paths and fully release the automatic learning capabilities of the model; Second, design heterogeneous network representation learning method suitable for dynamic and large-scale networks.
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2021,42(1):67-74, DOI: 10.7535/hbkd.2021yx01009
Abstract:
As the side effects of antibiotics are becoming increasingly prominent and the number of approvals is declining year by year, it is urgent to develop other active substances that are similar in functions and not easy to develop drug resistance. Antimicrobial peptides (AMPs) have broad-spectrum antibacterial activities, thermal stability and unique mechanism of action. They can not only play the role of anti-bacterial infection in vivo and promote apoptosis of cancer cells, but also be used as chemotherapeutic agents against virus and antibacterial materials for hospital settings. In this paper, developments related to antimicrobial mechanisms and activities of antimicrobial peptides against drug-resistant bacteria, anticancer and antiviral infection in the field of medicine are systematically reviewed. The problems of stability, hemolytic and toxicity of antimicrobial peptides are elucidated and the development prospects of AMPs in medicine are provided. Further research on AMPs can be carried out in the following aspects in the future. 1) Antibacterial mechanism in vivo are studied to promote the development and application of antimicrobial peptides；2）Structures of AMPs are optimized by replacing and modifying amino acid residues and hybrid peptides are synthesized to improve their activities, reduce side effects and prevent drug resistance; 3）Application of delivery systems for AMPs or combination of AMPs with green natural extracts is investigated to improve their antibacterial activity and bioavailability.
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SUI Bingdong, ZHANG Pai, WANG Xiaojun
2021,42(1):22-29, DOI: 10.7535/hbkd.2021yx01004
Abstract:
In order to solve the problems of low recognition accuracy and easily affected by illumination conditions in the gesture recognition, an improved YOLOv3 gesture recognition algorithm was proposed. Firstly, a smaller detection scale was added to the original three detection scales to improve the detection ability of small targets; secondly, DIoU was used instead of the original mean square error loss function as the coordinate error loss function, the improved focal loss function was used as the confidence loss function of the boundary frame, and the cross entropy was used as the loss function of the target classification loss function. The results show that when the improved YOLOv3 gesture recognition algorithm is applied to gesture detection, the map index reaches 90.38%, which is 6.62% higher than that before the improvement, and FPS is nearly twice as high as before. After the new model is trained by the improved YOLOv3 method, the gesture recognition accuracy is higher, the detection speed is faster, the overall recognition efficiency is greatly improved, the loss weights of simple samples and difficult samples are balanced, and the training quality and generalization ability of the model are effectively improved.
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MA Jing, WANG Ruiyang, WEN Ning
2021,42(1):75-81, DOI: 10.7535/hbkd.2021yx01010
Abstract:
In order to improve the oxidation resistance of 304 stainless steel, SiO2 thin film was prepared on the surface of stainless steel by sol-gel method with tetraethyl orthosilicate (TEOS) as raw material. The effect of film layers on the high temperature oxidation resistance of stainless steel at 900 ℃ was studied by means of oxidation kinetics, XRD, SEM and EDS. The results show that the adhesion of SiO2 film to stainless steel matrix is good, which promotes the selective oxidation on the stainless steel surface and the formation of protective Cr2O3 and NiCr2O4 oxide layers. The high temperature oxidation resistance of stainless steel is improved remarkably. The oxidation resistance of the sample coated with three layers of SiO2 film proforms the best, and the oxidation weight gain and oxidation spalling of the sample are only 58.1% and 41.4% of the uncoated sample after 100 hours of cyclic oxidation at 900 ℃. The high temperature oxidation resistance of stainless steel is effectively improved through SiO2 film coating, which is another attempt of surface treatment method applied to high temperature environment, and provides reference for other thin films prepared by sol-gel method.
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XIE Yinghua, LIU Zhaoxia, ZHANG Meimei, ZHANG Dongmei
2021,42(1):60-66, DOI: 10.7535/hbkd.2021yx01008
Abstract:
In order to avoid the irritation of metformin hydrochloride to the stomach and realize its release in the intestine, with metformin hydrochloride as the main drug and chitosan/sodium alginate as the composite support, the optimal formulation and preparation technology of metformin hydrochloride loaded pH-sensitive hydrogel microspheres were selected, and the pH-sensitivity and in vitro drug release characteristics were investigated. The formulation and process were optimized by single factor test and orthogonal test. The morphology was characterized by SEM. The entrapment efficiency and drug-loaded amount were determined by UV. The release degree was studied by rotating basket method. The results show that the optimized prescription is as following: chitosan and sodium alginate with a total concentration of 2%(mass-volume ratio), mass ratio of sodium alginate to chitosan =1∶1, mass ratio of drug to sodium alginate=2∶5, and 3.5% CaCl2(mass-volume ratio). The cumulative release rate is less than 4% in artificial gastric juice within 6 h, and up to 96.4% in artificial intestinal juice within 6 h. The formulation and process are stable and reliable, and the hydrogel microspheres have high mechanical strength, good biodegradability and stability. So it is a new metformin hydrochloride delivery system.
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CHEN Qi, ZHANG Renhui, HE Zhongyi, XIONG Liping
2021,42(1):1-7, DOI: 10.7535/hbkd.2021yx01001
Abstract:
In order to explore the lubrication performance of alcohols under high loads and high speeds conditions, especially the relationship between carbon-chain length and hydroxyl number and lubrication performance, the effects of carbon-chain length and hydroxyl number on the lubrication performance were well studied. The tribological properties of a series of alcohols were investigated by a four-ball tribological machine, and the effects of the carbon-chain length and the hydroxyl number on their lubricating properties were investigated by means of viscometer, transmission electron microscopy (TEM) and Raman. Experiments show that with the increasing of the carbon-chain length, the run-in period and the time for achieving stable friction coefficient were shorted, and the wear was reduced; with the increasing of the hydroxyl number, the wear decreased with no obvious run-in period and consistent fluctuation of friction coefficient for ethylene glycol and continuous decrease of friction coefficient for glycerol. It is found that friction-induced graphene is superior to amorphous carbon in effectively promoting the tribosystem to achieve the stable friction coefficient and shorten run-in period, which provides reference for the application of alcohols in the field of mechanical equipment.
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2021,42(1):8-14, DOI: 10.7535/hbkd.2021yx01002
Abstract:
In order to improve the positioning ability of ultra wideband network in non-cooperative indoor environment, the theory of centreless positioning algorithm was used to solve and analyze the output distance information of ultra-wideband ranging, and the relative positioning results were obtained. The positioning results of the system were compared with the results of the photoelectric calibration system, and the accuracy was evaluated. The results show that, compared with the traditional ultra-wideband positioning model, the combination of ultra-wideband ranging and centreless positioning algorithm can realize the centreless positioning and the relative positions among nodes, and finally determine the relative positions among nodes. The combination of UWB ranging and centreless positioning algorithm has good stability and accuracy in relative positioning, and can be widely used in various indoor and outdoor scenes.
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ZHANG Chunhui, WANG Laigui, ZHAO Quansheng, LI Weilong
2015,36(1):90-99, DOI: 10.7535/hbkd.2015yx01016
Abstract:
How to quantitatively evaluate the permeability change of coalbed subjected to liquid nitrogen cooling is a key issue of enhanced-permeability technology of coalbed. To analyze the evolution process of permeability of coupled coal deformation, failure and liquid introgen cooling, the coal is supposed as elastic, brittle and plastic material. Its deformation process includes elastic deformation stage, brittle strength degradation stage and residual plastic flow stage. Combined with strength degradation index, dilatancy index of the element and Mohr-Column strength criterion, the element scale constitutive model with the effects of confining pressure on peak-post mechanical behaviors is built. Based on the deformation process of coal rock, there exist two stages of permeability evolution of the element including decrease of permeability due to elastic contraction and increase due to coal rock element's failure. The relationships between the permeability and elastic deformation, shear failure and tension failure for coal are studied. The permeability will be influenced by the change of pore space due to elastic contraction or tension of element. Conjugate shear zones appear during the shear failure of the element, in which the flow follows so-called cubic law between smooth parallel plates. The calculation formulas of the permeability and the aperture of the fractures are given out based on the volumetric strain. When tension failure criterion is satisfied with the rock element fails and two orthogonal fractures appear. The calculation formulas of the permeability and the width of the fractures are given out based on the volumetric strain. Further, combined with the thermal conduction theory the permeability evolution model of coupled coal deformation, failure and liquid nitrogen cooling is presented. Then Fish function method in FLAC is employed to perform the model. The permeability's evolution process for coal bed cryogenically stimulated by flowing liquid nitrogen through gas production well in Wangyingzi mine, Liaoning province, is simulated and the results include: 1) When liquid nitrogen(LN2) is injected into a rock at warm reservoir temperature, heat from the rock will quickly transfer to the liquid nitrogen resulting in rapid cooling and contraction of coal bed. The nearer the position is to bore hole, the bigger the shrinkage deformation and thermal stress and coal fail when tension stress sufficiently built up. In this paper the tension failure band after 10 days' LN2 cooling is 0.65 m. 2) In tension failure area the cracks from cooling stimulation lead to the significant growth of permeability. The maximum permeability for element is 1.97×105 times more than that before cooling. 3) Apart from the bore hole, the thermal tensile stress leads to the growth of permeability at a rate of 1%~14%, far less than that in the tension failure area. 4) With increasing time the failure area gradually slowly grows up. It indicates that the longer cooling time does not mean better effects. 5) The cooling fracturing area is found to have a 1.0 m band. In practical engineering the pressure in hole bore and phase transition of water also influences the deformation and failure of coal, which leads to much more failure zone of cooling. 6) The evolution process of permeability of coupled coal deformation, failure and liquid introgen cooling can be better reflected by the model in this paper. This study is hoped to provide a simple but reasonable description of the permeability evolution of rocks subject to liquid nitrogen cooling.
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MENG Zhian, LU Suling, YAN Huajun, HAN Pengbiao, HU Xilei, WANG Tonghui, WANG Hao
2021,42(1):82-90, DOI: 10.7535/hbkd.2021yx01011
Abstract:
In order to solve the problems of backward production technology, long processing cycle and low material utilization rate in traditional U-shaped steel tie rods, an integrated steel tie rod forming process was proposed. Taking the preform forming of 35 steel tie rod U-shaped head as the research object, a three-pass heating upsetting method was designed. The DEFORM-3D finite element software was used to analyze the simulation results of the temperature field and stress field after upsetting under different process conditions. The hot forming process parameters with better forming effect were discussed, and the feasibility of forming was verified through experiments. The results show that the optimum hot forming process parameters of each pass are as follows: the initial forging temperature of the first pass is 1 150 ℃, while the punch speed is 20 mm/s; the initial forging temperature of the second pass is 1 150 ℃, while the punch speed is 30 mm /s; the initial forging temperature of the third pass is 1 100 ℃, while the punch speed is 20 mm/s. Under the hot forming process parameters, the forming forces of each pass are 1 520, 2 090, 5 290 kN, and the expansion forces of each pass are 5 870, 6 710, 8 830 kN, respectively. After upsetting, the metal streamline distribution is reasonable, there is no crossover and folding phenomenon, and the forming effect is good. The equivalent stress distribution inside the part is relatively uniform while preparing the preform in the three-pass hot upsetting method, which can form a good quality part. It provides a certain reference for the upsetting aggregate process design and equipment selection of the U-shaped head perform of 35 steel tie rod.
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YIN Yanan, ZHEN Ran, WU Xiaojing, ZHANG Chunyue, WU Xueli
2021,42(1):38-47, DOI: 10.7535/hbkd.2021yx01006
Abstract:
In order to solve the problem that ant colony algorithm is easy to fall into local optimum in UAV route planning, an improved ant colony algorithm was proposed. The upper and lower limits of pheromone volatilization factor and pheromone were set to prevent ants from falling into local optimum because pheromone on short path was too high or pheromone on long path was too low. At the same time, under the influence of multiple heuristic factors, the overall length of the path was taken as an adaptive heuristic function factor to determine the state transition probability. When the path length was large, the adaptive heuristic function factor was small, which reduced the probability of choosing the path by the ant colony. The experimental results show that the improved algorithm reduces the path length by 6.4% and the variance of the optimal path length by 85.78%, which increases the consideration of environmental integrity, shortens the path length, reduces the number of iterations, and jumps out of the local optimum. In the case of increasing environmental complexity, the algorithm can effectively choose a better path and provide a theoretical basis for UAV route planning after introducing the adaptive heuristic function factor.
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Research on impulse interference suppression method based on short time fractional Fourier transform
WANG Xiaojun, XUE Linbo, WANG Yanpeng
2021,42(1):15-21, DOI: 10.7535/hbkd.2021yx01003
Abstract:
In order to solve the problem that the impulse interference near the service frequency band of aviation radio navigation affects the receiver, and further improve the anti-jamming ability of GNSS system, a impulse interference suppression method based on STFRFT (short time fractional Fourier transform) was proposed. The optimal rotation order of the received signal was determined, and STFRFT was applied to the signal to obtain the two-dimensional distribution of time-frequency surface through coordinate rotation. Under the optimal order, the adaptive time-varying filter was used to separate the interference and the signal, so as to suppress the interference. The simulation results show that the adaptive filtering algorithm based on STFRFT has the best effect of eliminating interference compared with several traditional methods, and retains more useful signals while suppressing impulse interference. By combining STFRFT and adaptive time-varying filtering technology, the ability of suppressing impulse interference is improved, which provides some reference for the impulse anti-jamming technology of aviation radio navigation service.
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LI Chunhua, QIN Yunfan, LIU Yukun
2021,42(1):30-37, DOI: 10.7535/hbkd.2021yx01005
Abstract:
Aiming at the problem of poor precision performance of traditional Bayesian model saliency detection algorithm, a Bayesian model saliency detection algorithm based on improved convex hull was proposed. Firstly, the foreground of the image was extracted by the manifold ranking algorithm, which was used as the prior probability in Bayesian model. Secondly, Harris corner detection algorithm based on color enhancement was used to detect the feature points of the image in three color spaces of RGB, HSV and CIELab; the convex hulls in RGB, HSV and CIELab spaces were constructed respectively; and the intersection of convex hulls were obtained. Thirdly, the saliency region map was calculated by Bayesian model according to the prior probability and the observed likelihood probability obtained by combining convex hulls and color histograms. Finally, the proposed algorithm was tested in two public data sets MSRA and ECSSD. The experimental results show that the proposed algorithm can suppress the background noise effectively and detect the salient areas completely. The test results of F-measure value in MSRA and ECSSD databases are 0.87 and 0.71 respectively, and the accuracy-recall rate curve is higher than that of traditional classical algorithms in complex image databases. The proposed algorithm improves the detection effect of the traditional classical algorithm and the accuracy of saliency map detection.
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LIU Qing, LIU Bin, WANG Guan, ZHANG Chen, LIANG Zhixing, ZHANG Peng
2019,40(1):68-78, DOI: 10.7535/hbkd.2019yx01011
Abstract:
In recent years, the research on Digital Twin is in the ascendant. As a new paradigm or concept, it shows great potential. However, the connotation and scope of the Digital Twin concept is still uncertain, especially the Digital Twin Model definition is not clear.According to the pattern category, the Digital Twin Model can be divided into general model and special model, in which the special model is still the focus of current research, and the research content is mainly embodied in the use of Digital Twin method to model specific projects. It also includes concept for developing specialized models. These specific projects in addition to the traditional manufacturing related to parts measurement and quality control, manufacturing, design and work processes, as well as system management, but also in the field of biomedical applications and applications for petroleum engineering and so on. There are many tools and techniques for developing special models, such as general industrial software, special industrial software, simulation platform and self-developed secondary development tools, etc.The research object of the Digital Twin general model is not specific to a specific project, but how to represent the controlled elements of the model as a group of common objects and the relationships between these objects. This provides a consistent approach to the management and communication of controlled elements between different environments. The research on the general model is mainly divided into the conceptual research and the model implementation method; the research heat of the two directions is almost the same. Conceptual research ranges from product lifecycle management to system behavior description, such as general system behavior and system reconfiguration, and to product configuration management, to specific workflow, such as design methods, manufacturing systems and manufacturing processes. The research content is relatively divergent, and there is no particularly prominent hot spot. The research of Digital Twin general model implementation is mainly reflected in the modeling language construction, the model development methods exploration, the specific tools usage, the Meta-model concept implantation and the model algorithm exploration.Digital Twin Model is one of the core areas of Digital Twin research. Its future research focuses on how to integrate the external features and intrinsic properties from different Digital Twin artifacts into a model with interoperability, interactivity and scalability for more efficiently realizing the information flow between the physical world and the digital world, thus achieving the universal Digital Twin application, and then supporting the CPS (Cyber Physical Space) and CPPS (Cyber Physical Production System) construction. To this end, the next problem in the Digital Twin Model needing to be solved first is how to dock the standard reference architecture, such as the RAMI4.0 (Reference Architecture Model Industrial 4.0) proposed by Germany and the IMSA (Intelligent Manufacturing System Architecture) by China, etc. Secondly, the Digital Twin Model needs a unified method to describe and it also needs consistent conclusions, in order to standardize the models established by independent development, thus improving the interoperability and scalability of the model. Otherwise, the performance of the model will decrease significantly as the system scales raise. Thirdly, the research on China's Digital Twin Model requires the support of domestic professional industrial software and modeling software, so that the Chinese scholars can carry out in-depth research that is more in line with national conditions.
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2021,42(2):180-194, DOI: 10.7535/hbkd.2021yx02011
Abstract:
As one of the important supporting technologies for the construction of CPS(cyber-physical space),the digital twin has been applied in many fields,such as aerospace,intelligent manufacturing,smart city,smart medical care,smart education,etc.However, some problems in the practice process has also appeared: the generalization of the concept of digital twin leads to the misunderstanding,which results in the inconsistency of production,teaching,research and application goals,and the practice results are not recognized by the target users; The lack of general and effective methods in concrete implementation leads to the limitation of the results,which results in the lack of universal practical cases and difficulty in forming recognized typical cases.To solve these problems,it is necessary to restrict the concept boundary of digital twin and extend the boundary of digital twin method,so as to form a new boundary of digital twin,promote the formation of consensus,increase implementation methods and promote its better development. 河北科技大学学报 2021年 第2期 刘〓青，等：数字孪生的新边界 Conceptually,physical entity is a collection of materials with various properties,which is characterized by complexity,authenticity and immediacy,and can dynamically evolve with the change of external conditions according to objective laws.In the study of mapping physical entities to digital twins,it is easy to expand the scope of concept to include simulation (the simulation of dynamic evolution process),data (external conditions),and even physical entities (objects).As a result,the concept of digital twin will lose its core and it is difficult to from a consensus.In terms of methods,based on the detailed investigation and analysis of related applications in multi-scenarios,the existing research on digital twin often goes beyond the perception process of physical entities,and directly relies on the models or modelconstruction methods in the original professional fields.While this method has made some progress,its limitations have already been revealed.Firstly,the existing models are mostly focused on subdivision fields,which can not be used universally among fields.Secondly,there are few existing models that reflect the characteristics of high fidelity,multi-scale and multi-physical fields of the digital twin model,and even less information flow corresponding to the whole life cycle.Direct application can not guarantee the effective realization of digital twin; Thirdly,entering the modeling process directly from the height of existing cognition may cause huge costs.For example,the ADT program,a world recognized typical case of US military,was constructed in ten years and with huge investment in manpower and material resources,which further hinders the industry from entering the practice of digital twin.In order to meet these challenges,in terms of conceptual boundary,this paper proposed that the digital twin should return to the essence of its digital model,and effectively restrict the model as the center,so as to promote the understanding of all parties involved in production,teaching and research to reach an agreement.As for the extension of method boundary,this paper put forward a multi-sensory oriented digital twin model construction method,that is,according to the general process of human understanding of the physical world,firstly obtained perceptual knowledge of features through various perception methods,and then further formed rational knowledge through various cognitive processes,from shallow to deep,from easy to difficult,from simple to complex.At first,the digital twin initial model of physical entity was established by multi-sensory methods,such as visual perception,auditory perception,tactile perception and dynamic perception,gustatory/taste perception,and combination with control data reflecting the change of conditions,thus focusing on the complexity and authenticity of physical entity at the beginning of the model establishment,fully embodying the characteristics of the digital twin model,and effectively enhancing the practicability and universality of the model. Then,the initial model was gradually matched with the existing cognitive knowledge framework,and the control data returned from the physical entity was used for continuous iteration.In this way,information of various property changes,real-time/near-real-time reactions,various objective laws and behavioral logic affecting the physical entity under specific external conditions can be gradually added to the digital twin model according to the actual needs of the research field,thus effectively controled the scale and cost of the model and gradually realized the information flow in the whole life cycle. Third,the optimized digital twin model was further used in theoretical and practical research,such as simulation,planning,optimization,decision-making,etc.,so as to promote the development of various studies.The application prospect of the multi-sensory oriented digital twin model in computer image scanning,cultural heritage protection,medical treatment,education and some special fields was prospected.
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QIN Si-liang, WANG Qing-guo, QU Zhao-ming, LEI Yi-san
2012,33(4):309-312, DOI: 10.7535/hbkd.2012yx04007
Abstract:
The permittivity of carbon fibers in different composites is calculated and discussed by using M-G equations, Bruggeman equations and generalized M-G equation. Results show that for high draw ratio fibers, all the three equations can calculate out the permittivity with the same numerical level and variation trend. Generalized M-G equation and M-G equation have a similar result but Bruggeman''s result is smaller. All three equations become invalidation when fibers'' concentration reaches its percolation threshold, which means that all three equations are useful at low concentration.
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WEN Juan, LI Fu, DING Junjun, LI Gang
2015,36(1):1-8, DOI: 10.7535/hbkd.2015yx01001
Abstract:
Urban rail transit vehicles have been more and more attractive to people as a kind of fast, comfortable, energy-saving, environmental protection and safe transportation. But because of the vehicle noise and vibration, urban rail vehicles also face severe challenges. The research of resilient wheels has been continuously developed and improved. Based on the review of development background and structure sorts of resilient wheels, the advantages of resilient wheels are described, and the research status of noise and vibration reducing, infinite element strength analysis, vehicle dynamic analysis and the wheel-rail wear of resilient wheels are discussed. Taking the low-floor LRVs (light rail vehicles) in domestic and overseas as example, the development and application of the resilient wheels in city rail transit is described, and the application prospects of the resilient wheels in LRVs in domestic and the future research direction of elastic wheel are discussed.
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CUI Hai-ting, ZHANG Gai, JIANG Jing-zhi
2012,33(5):453-458, DOI: 10.7535/hbkd.2012yx05016
Abstract:
By using the solidification/melting model of FLUENT software, the melting and solidification process of the aluminum-silicon alloy in a cylinder heat storage with double wall were simulated numerically. Considering the third kind of boundary condition, the dynamic temperature field distribution and the position of the phase interface change moving with time are obtained. And the melting and solidification duration time is also calculated. The results have important reference value for the numerical simulation of the phase change problem and the design of phase change energy storage device.
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2008,29(4):299-304, DOI: 10.7535/hbkd.2008yx04010
Abstract:
Based on the developed rehabilitation manipulator, study on the control system is carried out, such as embedded system platform with the ARM microprocessor S3C2410as its core, motor control module and data acquisition module based on serial peripheral interface (SPI) bus, control software and graphical user interfaces (GUI) etc. According to the mechanical system, a sensor system is also designed to realize the function of acquisition of rehabilitation dada during rehabilitation motion. The test proves the feasibility of the system which can be used in clinic in future.
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2020,41(2):133-147, DOI: 10.7535/hbkd.2020yx02004
Abstract:
The network representation learning algorithm represents the information network as a low-dimensional dense real vector carrying the characteristic information of network nodes, and is applied to the input of downstream machine learning tasks. With the development of machine learning and deep learning, network representation learning has been widely used due to its powerful modeling capabilities and extensive applications. The network representation learning methods and their application were summarized. Firstly, the current network representation learning methods at home and abroad were categorized into different groups, including traditional methods, network structure-based embedding, embedding with attribute information, and spectral-based Graph Convolutional Networks, spatial-based Graph Convolutional Networks and Graph Attention Networks. Then various models were expounded, and the applicability and characteristics of the models were compared. Secondly, the related applications of network representation learning, including recommender system and biomedical field, were introduced. Commonly used data sets are also given, and open source implementations of representation learning models and powerful graph deep learning libraries for reference were organized. Finally, the developing trend of network representation learning was summarized and forecasted. Deep graph neural network, dynamic and heterogeneous network representation, and generalization ability of network model will need to be further studied.
