Table of Content

30 August 2023, Volume 29 Issue 4

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Application advances of ionic liquids in hydrometallurgical leaching and electrodeposition 

WANG Fuqian, LU Minghui, WANG Shujuan, WANG Fei, XIA Xuewen, GENG Shuhua, ZOU Xingli, LU Xionggang

2023, 29(4):  569-589.  doi:10.12066/j.issn.1007-2861.2506

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Because of their excellent physical and chemical properties, namely, their good solubility, high conductivity, wide electrochemical window, good thermal and chemical stability, reusability, and easy regeneration, ionic liquids have been widely used in many fields such as organic synthesis, separation, electrochemistry, catalysis, metallurgy, nuclear energy recycling, and nanomaterials. In particular, the introduction of ionic liquids enables metallurgical reactions to occur at low temperatures, which in turn reduces energy consumption and pollution. Therefore, this new “green” solvent has great application potential in the field of metallurgy. This paper summarizes the research and application status of ionic liquids in hydrometallurgy, with a focus on the dissolution of metals and their oxides, the leaching of complex minerals and electronic wastes, and the preparation of various metals and their alloys by electrodeposition with ionic liquids as the medium. The developmental prospects of ionic liquids in metallurgy are also discussed.



Effect of blanching combined with 1-MCP treatment on quality of fresh-cut celery during storage 

KONG Qianqian , ZHANG Jianhua , ZHONG Yaoguang , CHENG Yang

2023, 29(4):  590-601.  doi:10.12066/j.issn.1007-2861.2522

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The effects of treatment using 1-methylcyclopropene (1-MCP) and blanching on the storage quality of fresh-cut celery stored at low temperature were explored. Freshcut celery was blanched at 50 ℃ for various durations (0∼80 s) and treated with different 1-MCP volume fractions (0∼1.8 µL/L). The results showed that the optimum conditions for blanching were 50 ℃ for 20 s and that for 1-MCP treatment were 0.9 µL/L for 24 h. Fresh-cut celery samples were treated by one or both of the techniques and then refrigerated at (4±1) ℃. The results showed that the combination of blanching and 1-MCP treatment was more effective in slowing membrane lipid peroxidation during storage, reducing the levels of reactive oxygen species (ROS) such as superoxide anion (O₂^-) and hydrogen peroxide (H₂O₂), and decreasing the malondialdehyde (MDA) content. Furthermore, this treatment preserved high superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities in the fresh-cut celery as well as maintained the content of endogenous antioxidants such as reduced vitamin C (VC) and reduced glutathione (GSH). Thus, the treatment retained both the hardness and color of fresh-cut celery to a certain extent and increased the refrigeration storage time by 3∼6 d.



Effect of high-pressure homogenization on the structure and properties of insoluble dietary fibres of millet bran and fibre dispersion in water 

XU Chan , PEI Hua , WANG An , LU Zhaoxin , ZHAO Haizhen

2023, 29(4):  602-614.  doi:10.12066/j.issn.1007-2861.2527

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This study investigated the effects of number of times of high-pressure homogenization on the structural properties of insoluble dietary fibres (IDFs) derived from millet bran fermented using Bacillus amylolyticus and the physical stability of aqueous IDF suspensions. Millet bran dietary fibres (DFs) were obtained through liquid-state fermentation (30 ◦C, 180 r/min, 48 h) using Bacillus amylolyticus and further modified via high-pressure homogenization. The physicochemical properties of the homogenised IDFs were evaluated using various techniques, and their structural characteristics were analysed through Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The particle size distribution, viscosity, zeta potential, and physical stability of the IDF suspensions in water were evaluated before and after high-pressure homogenization. The water-holding capacity and swelling capacity of the IDFs obtained via millet bran fermentation using Bacillus amylolyticus increased significantly after 0, 5, 10, 15, 20, and 25 cycles of high-pressure homogenization. In particular, the water-holding capacity and swelling capacity increased by 80.5 and 81.84%, respectively, after 25 cycles of high-pressure homogenization compared with those of the untreated IDFs. FTIR spectra revealed that no new chemical functional groups were generated after high-pressure homogenization, but the intensities of certain FTIR peaks were weakened, indicating the partial degradation and rearrangement of lignin and hemicellulose, and decreased ordering degree of the crystalline domains. Combined with the XRD results, it can be inferred that, although the millet bran IDFs exhibited the characteristics of natural type I cellulose, their crystallinity decreased with increasing cycles of high-pressure homogenization. The average particle size of the IDFs in aqueous suspensions gradually decreased with the increase in high-pressure homogenization recirculation, and the absolute zeta potential value increased gradually. When the homogenization recirculation reached 20 times, the aqueous fibre suspension exhibited good physical stability. Moreover, as the cycle number of high-pressure homogenization recirculation increased, the apparent viscosity of the aqueous IDF suspension increased steadily, and all samples exhibited shear-thinning behaviour. High-pressure homogenization can improve the structure and physicochemical properties of IDFs derived from fermented millet bran and enhance the stability of aqueous IDF suspensions.



Effect of a bacterial laccase LacHa protein from Halomonas alkaliantartica on the quality of wheat bread 

WANG Jingjing, ZHOU Peng, BAI Han, ZHANG Ran, FANG Xue, ZHANG Yan

2023, 29(4):  615-627.  doi:10.12066/j.issn.1007-2861.2516

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In this study, the laccase from Halomonas alkaliantartica was used as the research material. The laccase gene was heterolytically expressed in Escherichia coli; a recombinant laccase was obtained with a molecular weight of 68.5 kDa and an enzyme activity of 224.5 U/L. This enzyme was then used in the production of wheat bread, with a blank group of bread produced without laccase as the control. To create the various experimental groups, laccase was added in amounts of 1, 2, 3, 4, 5, or 6 U. Compared with the blank group, the specific volume of the wheat bread was the largest in the 5 U laccase group. Under this condition, the hardness, adhesion, and chewability of the wheat bread significantly decreased (p < 0.01). As storage duration increased, the quality of the bread decreased, but the hardness and stickiness of the experimental bread (5 U laccase) were still better than those of the control group on the third day. This study shows that laccase, as a flour improver, has considerable potential for use in the preparation of baked foods and broad application prospects in the field of food processing. 



Effects of applying livestock manure and mushroom residues on heavy metal accumulation in crops

Jin Zhi, Hu Xuefeng, Lan Wenchong, Li Mei, Zhang Weijie

2023, 29(4):  628-638.  doi:10.12066/j.issn.1007-2861.2296

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The effects of applying the culturing residues of Agaricus bisporus and Flammulina velutipes, pig manure and cattle manure on the growth of and heavy metal accumulation in the crops were studied through two field experiments. The content of heavy metals such as Cu and Zn in pig manure was significantly higher than that of the mushroom residues and cow manure. The content of Cu, Zn, Pb and Cd in Agaricus bisporus residue was significantly higher than that of Flammulina velutipes residue, which was related to the addition of a small amount of chicken manure to the culture base of Agaricus bisporus. The applications of the mushroom residues and manures have significant effects on yield increase. The yield of green pepper in the pig manure treatment was significantly higher than the other fertilization treatments. In pig manure treatment, the heavy metals of Cu, Pb, and Cd in crops are mainly concentrated in the roots; the content of Zn, Pb, and Cd in green pepper fruits increased significantly; the content of Cu, Zn, Pb, and Cd in rice increased significantly. However, the heavy metal content of green pepper and rice are within the safe range of food. The treatment of Agaricus bisporus residue significantly increased Cd in the roots of green peppers and increased Pb content in the fruits. In the treatment of Agaricus bisporus residue in a double amount, heavy metals are mainly concentrated in the roots of rice; the content of Pb and Cd in rice also increased significantly. The long-term application of pig manure and Agaricus bisporus residue will cause heavy metal accumulation risks in the soil and crops, which should be paid high attention to. In contrast, the application of Flammulina velutipes residue and cow manure has a lower risk of heavy metal accumulation in soil and crops



A cellular automaton model for urban road networks considering global traffic information 

LI Shujian , SHENG Zhe , DONG Liyun ,

2023, 29(4):  639-650.  doi:10.12066/j.issn.1007-2861.2515

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The origin-destination pair of vehicles was introduced into the Biham-MiddletonLevine (BML) model with four-directional traffic to investigate the dynamical evolution process of urban traffic flow under a periodic boundary. The driver selects the shortest path to their destination considering not only the relative position but also the parity of rows (columns). When a static route choice strategy is used, local gridlocks occur at very low density because the path is already determined at the initial moment, and it is ineffective to improve the critical density. Using the dynamic route choice strategy based on global traffic information, the driver can change the direction of motion to avoid congested areas when the steering condition is satisfied according to the speed threshold. Simulation results show that using a smaller threshold value can effectively reduce traffic congestion without significantly increasing travel distance. The fluctuations of mean speed can be further reduced if a local control strategy in a subdomain is adopted. 



Pedestrian crossing simulation driven by a coupled model of deepdeterministic policy gradient algorithm 

SONG Tao , , WANG Yanlin , WEI Xinkai , WEI Yanfang

2023, 29(4):  651-665.  doi:10.12066/j.issn.1007-2861.2519

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The simulation of pedestrian flow plays an important role in public safety research. However, the enhancement of agent authenticity in simulation environments remains a challenge. Herein, we propose simulating pedestrian crossing behaviour at unsignalized intersections using a deep deterministic policy gradient algorithm to drive a two-dimensional optimal velocity pedestrian model. We constructed a strategy exploration scheme that considered two types of two-dimensional optimal velocity pedestrian models: non-velocity and velocity difference terms. The analysis revealed that the model considering the velocity difference term tended to flexibly select relatively safe actions, thus its action-selection strategy was considered optimal. Furthermore, this model completely avoided pedestrian collisions and ensured pedestrian safety. 



Urban expressway on-ramp control based on improved NSGA-II algorithm of reinforcement learning 

CHEN Juan, GUO Qi

2023, 29(4):  666-680.  doi:10.12066/j.issn.1007-2861.2435

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To alleviate urban expressway congestion and exhaust emissions, an improved NSGA-II algorithm based on dueling deep recurrent Q network (Dueling DRQN-NSGAII) was proposed. This method combined dueling deep Q network (Dueling DQN), deep recurrent Q network (DRQN), non-dominated sorting genetic algorithm II (NSGA-II), and applied Dueling DRQN-NSGA-II to ramp control. In addition to considering the merging of ramp vehicles to improve expressway traffic efficiency, the environmental and energy indicators were also considered, and the exhaust emissions and fuel consumption were used as evaluating indicators. Dueling DRQN-NSGA-II algorithm was compared with NSGAII algorithm in addition to no control situation and other algorithm. The experimental results showed that compared to the no control situation, the proposed algorithm effectively improved the road network traffic efficiency, alleviated environmental pollution and reduced energy consumption. Compared with the no control situation, the total time spent (TTS) was reduced by 16.14%, the total emissions (TE) was reduced by 9.56%, while the total fuel consumption (TF) was improved by 43.49%.



Shared parking slot allocation considering parking preferences and priorities of users 

JI Yangbeibei , LU Xueqing , DONG Jichang , LAI Zerong

2023, 29(4):  681-693.  doi:10.12066/j.issn.1007-2861.2395

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In order to optimize the allocation of shared parking spaces for hospital parking users, the differences in urgency and parking preferences of hospital parking users are considered. Two parameters, assignment priority and subjective parking utility, are introduced, and a shared parking space allocation model with the primary objective of maximizing the acceptance rate of requests considering assignment priority and the secondary objective of maximizing the total subjective parking utility is proposed. Three allocation mechanisms are proposed and comparatively analyzed: static allocation mechanism (SA), a dynamic allocation mechanism (DA) and dynamic allocation mechanism considering emergency parking space reservation (IDA). The study shows that this model can significantly improve the acceptance rate of requests from urgent and elderly parking users, and match users with parking spaces that better meet their parking preferences. It can effectively increase the request acceptance rate of emergency parking users by setting a certain percentage of emergency reserved spaces.Setting 8% of spaces as emergency reserved spaces can keep the request acceptance rate of emergency parking users at a high level (above 95%) and significantly increase the comprehensive benefits of shared parking allocation. 



Anylogic-based bottleneck identification and evacuation organization optimization of large passenger flow in rail transit stations 

CHEN Leiyu, ZHANG Ruhua, MA Mingdi

2023, 29(4):  694-704.  doi:10.12066/j.issn.1007-2861.2433

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This study takes Jinan Yuanboyuan Metro Station as the research object and establishes a pedestrian flow model by analyzing the behavior characteristics of pedestrians at different equipment and facilities. AnyLogic software is used to build a simulation experiment platform to simulate emergency evacuation for three different types of large passenger flow situations. The simulation results reveal the following: In the case of predictable large passenger flow, when the increase in station passenger flow is small, the passenger flow density on the platform layer is large, and the evacuation capacity of the station can be improved by shortening the train running interval. When the station passenger flow increases significantly, the station security check area is congested, and a security check channel needs to be added. In the event of unpredictable large passenger flow, the station can meet the evacuation standards in most cases, but the stairway and exit gate are still the bottleneck of passenger flow; therefore, the evacuation of passenger flow during peak hours needs to be guided by certain measures. By simulating the emergency evacuation process under two large passenger flow conditions, the bottleneck of the station is identified, and effective measures are taken to improve it, which is of great significance to ensure the safety and efficiency of passenger evacuation, improve station service capacity, and formulate the emergency evacuation plan. 



ANALYTIC SOLUTION OF BENDING DEFORMATION OF COMPOSITE BEAMS WITH INTERFACIAL SLIP AND LIFT

YANG Xiao, WANG Huan

2023, 29(4):  705-719.  doi:10.12066/j.issn.1007-2861.2309

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In order to consider effects of longitudinal slip and vertical uplift of composite beam connection surface, the governing equations of composite beam bending deformation are established with fundamental unknowns of the longitudinal slip and vertical deflections of sub beams under assumption of sub-beams satisfying Euler-Bernoulli bending theory. By using Laplace transform and its inverse Laplace transform, the analytical solutions of deflection, slip displacement, axial force and bending moment of simply-supported composite beam under uniform load are obtained. Assuming that the material and geometric parameters of the two sub-beams are the same, the effects of the loading mode and the longitudinal slip and vertical uplift stiffnesses of the connection surface on the bending deformation and internal forces of the simply supported composite beam are analyzed. The results show that with the increase of interface longitudinal stiffness, the deflection, slip displacement and bending moment of composite beams decrease first and then tend to be constant, while the axial force of composite beams increases first and then remains constant; And when the composite beam is loaded from the top sub-beam, with the increase of the vertical stiffness of the interface, the deflection and bending moment of the upper beam first decrease and then tend to be constant, while the deflection and bending moment of the lower beam first increase and then tend to be constant; When the composite beam is loaded at the bottom sub-beam, it is opposite to that at the top; The deformation and internal force of composite beams have nothing to do with the vertical stiffness when the upper and lower loads are the same.



Research on Optimization of the Location of Precast components in Prefabricated Shear Wall Structures

LI Jiazhe, ZHU Jiejiang

2023, 29(4):  720-733.  doi:10.12066/j.issn.1007-2861.2313

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The optimization of the location of precast components is an important method of cost control in the optimal design of prefabricated shear wall structures. With the selection of precast components determined, the location of precast wall-beam combined components is optimized by combining immune genetic algorithm, the minimum precast component volume is the objective function, the structural torsional displacement ratio and story drifts are the constraints. The optimization results of the algorithm show that the optimized location of the precast components combined with the immune genetic algorithm can satisfy the structural constraints, the volume of the precast components is smaller and the optimization is more economical.



An efficient damping system for continuous girder bridges 

LI Ziyang, XU Hao, ZHANG Qiang, YANG Qiaorong, XU Zidong

2023, 29(4):  734-744.  doi:10.12066/j.issn.1007-2861.2344

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In this study, an efficient damping system for continuous girder bridges (EDBs) is proposed to improve the energy dissipation efficiency by amplifying the relative displacement of the dampers. To investigate the applicability of this damping system in the seismic resistance of continuous girder bridges, an experimental model of both common and magnified viscous dampers with triple displacements is designed to conduct a reciprocating loading test under the action of a sine wave. The amplification effect is verified by comparing the test results with those under ordinary dampers. Finite element software is used to establish a multi-mass point model of a six-span continuous bridge to analyze the pier bottom shear force, pier bottom bending moment, displacement, hysteresis curve, and energy dissipation curve of different damping schemes under the action of three seismic waves. The results show that the efficient damping system of the continuous girder bridge effectively dissipates the seismic energy and reduces the seismic response of the bridge structure.



Mechanical model and seismic response analysis of a double-layer conical unbonded base isolation bearing 

HAO Ruikang, HE Wenfu, ZHANG Qiang, CHEN Mufeng

2023, 29(4):  745-757.  doi:10.12066/j.issn.1007-2861.2366

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To solve the insufficient seismic capacity of rural houses in high intensity areas, a double-layer conical non-bonded isolation bearing that has a good damping limit and simple and practical characteristics is proposed for seismic resistance of low-rise and multistorey buildings. Through the analysis of the deformation of the double-layer conical unbonded isolation bearing, third-order mechanical properties and the restoring force model of the bearing are obtained. The reliability of the numerical analysis model is verified by comparing the results of the static test of the single-layer conical non-bonded isolation bearing and those of a finite element model. Based on the numerical model of the bearing, the influence of the main parameters, such as the thickness of rubber material, inclination angle of the bearing, vertical compressive stress and horizontal displacement on the mechanical properties and energy dissipation capacity of the double conical isolation bearing, is further investigated. The results show that an increase in the thickness of the rubber material leads to a higher energy dissipation of the bearing. Furthermore, the increase in inclination angle results in a higher third-order stiffness of the bearing. Finally, based on the structural response analysis of the double conical non-bonded isolation structure, the structure composed of the double conical non-bonded isolation bearing has good damping effect. 



Effect of fiber concrete on the mechanical properties of deeply-buried water storage and sewage shie^ld tunnel 

ZHANG Jinsheng , ZHUANG Qianwei , , LI Dong , ZHANG Chi

2023, 29(4):  758-768.  doi:10.12066/j.issn.1007-2861.2397

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Taking the deeply-buried water storage and sewage shield tunnel project implemented in Suzhou River of Shanghai as the background, the full-scale static load tests of segment beams and joints poured with three groups of different fiber reinforced and one group of non-fiber reinforced concrete were carried out. The tests were conducted using the multi-functional return frame test system to explore the effects of three kinds of fiber reinforced concrete on the mechanical properties of segments of deeply-buried water storage and sewage shield tunnel. The results of segment beam test demonstrated that synthetic fiber improved the tensile capacity of concrete. When the internal water pressure reached 0.5 MPa, different fibers could reduce the stress of reinforcement by 8%∼22%; moreover, synthetic fiber could effectively delay the occurrence and inhibit the development of cracks. The crack width of Barchip fiber segment was reduced by 40%, that of T&W fibers was reduced by 20%, and that of steel fiber was reduced by 28%. The results of segment joint test indicated that synthetic fiber could improve the overall rigidity of joint specimens; accordingly, the strength of Barchip fiber was increased by 24%, that of T&W fiber was increased by 10%, and that of steel fiber was increased by 17%. The synthetic fiber-reinforced concrete could effectively reduce the degree of broken corner failure in the joint compression zone when the bolt underwent yielding. In general, Barchip fiber performed better than steel fiber in inhibiting crack development and improving the overall rigidity of segments and joints, while the T&W fiber performed slightly worse than steel fiber.



Analytical study on temperature field of high-level radioactive waste disposal repository 

HE Luqiang, ZHOU Xiangyun, SUN Dean

2023, 29(4):  769. 

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The temperature distribution characteristic of a high-level radioactive waste disposal repository is important for evaluating its safety performance and designing appropriate thermal dimensions. Based on the conceptual design of the KBS-3V disposal repository, a two-dimensional axisymmetric heat transfer model for a single nuclear waste canister is established. By means of the finite Fourier sine transform, the separation of variables and the impulse theorem, an analytical expression is obtained from which the surrounding rock temperature at any point, under a single-waste-canister heat release condition, can be determined. The validity of the proposed model is verified by comparing the results of existing semi-analytical solutions with linear heat source solutions. The surface temperature of the waste canister is obtained by superposing the temperature difference of the buffer layer on the rock wall temperature, before analyzing the near-field temperature evolution of the waste canister. Finally, the effect of material thermal parameters, nuclear waste decay parameters, and geometric parameters on the waste canister surface temperature are analyzed. The results show that the near-field temperature of the waste canister increased rapidly, reaching a peak within the first two years of the canister being disposed of, after which the temperature decreases slowly with the disposal time. The buffer temperature gradient is large while the rock temperature gradient is small. The larger the thermal conductivity of the buffer material and surrounding rock, the thinner the buffer layer, the smaller the combustion value of nuclear waste, and the longer the cooling time, the lower the surface temperature of the waste canister. The thickness of the bentonite pellet layer has a greater effect on the surface temperature of the waste canister than that of the bentonite block layer, mainly because of the lower thermal conductivity of granular layer material.



Experimental analysis based on three fracture toughness test methods 

WANG Yongdong , BAO Chen , NING Dong , WANG Yiqing , JING Yi , PU Chenghao

2023, 29(4):  786-795.  doi:10.12066/j.issn.1007-2861.2429

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The theories of fracture toughness measurement for three J-integral test methods, including unloading compliance method, normalization method and S_pb separation parameter method, are summarized, and the three methods are used to test the fracture toughness of a metal material. It is found that all the three methods can obtain effective J_IC values. The J_IC value obtained by the unloading compliance method is slightly greater than those obtained by the other two methods, and the result obtained by the normalization method is slightly smaller than those obtained by the other two methods but close to that by the S_pb separation parameter method.



Effect of electrode on the performance of Cd_1−xZn_xTe photodetector 

SHI Haozhi , WANG Linjun

2023, 29(4):  796-802.  doi:10.12066/j.issn.1007-2861.2484

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CdZnTe has a wide band gap and chemical stability, making it an ideal material for the preparation of UV (ultraviolet) photodetectors. Good contact between the electrode and CdZnTe plays a key role in the preparation of highly sensitive and stable UV detectors. In this work, a single electrode Au/CdZnTe/Au detector and a composite electrode Au/GaZnO(GZO)/CdZnTe/GZO/Au detector were prepared, and the effects of different electrodes on the performance of CdZnTe UV photodetectors were investigated.