Table of Content

30 August 2024, Volume 30 Issue 4

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Entrance ramp control of expressway considering macro carbon emission threshold

JI Yangbeibei, TONG Shaocheng, LIU Jingwen, DONG Jichang, FU Wurong

2024, 30(4):  565-580.  doi:10.12066/j.issn.1007-2861.2576

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To alleviate the increasing serious traffic congestion and pollution problems on expressways, the impact of carbon emissions was considered based on the classic ALINEA ramp control algorithm. A macrocarbon emission threshold index was proposed by combining real-time carbon emission measurement indicators with occupancy indicators using a macroscopic fundamental diagram. A carbon emission-ALINEA (CE-ALINEA) hierarchical control algorithm was constructed, which considers the carbon emissions reduction of the mainline and ramps as well as the improvement in road network operation efficiency. Furthermore, the control effects of different control algorithms were compared via VISSIM simulation experiments. The results showed that when compared to ALINEA control, the CE-ALINEA control can not only effectively reduce mainline emissions and improve main-line operation efficiency, but also significantly reduce the increase in ramp carbon emissions due to ramp control. Furthermore, CE-ALINEA control can effectively measure mainline carbon emissions and have a stable control effect on mainline traffic by changing the layout of detectors. As the penetration rate of electric vehicles increases, the carbon reduction effect of CE-ALINEA weakens. However, when compared to ALINEA, it continues to exhibit a better reduction effect on ramp carbon emissions.



Control strategy of lateral stability for double trailer trains

ZHAO Kan, QU Huaikun, QUAN Yukun, SONG Yunlong, LIU Qingjie, QIU Zhaowen

2024, 30(4):  581-594.  doi:10.12066/j.issn.1007-2861.2491

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Compared with the traditional semi-trailer, the double trailer train has higher transport efficiency and lower transport cost, and is more suitable for the future development trend of green, convenient and efficient road transport. However, the long total length of the vehicle body and the number of its components will inevitably affect the stability of the vehicle. In order to study and verify the improvement of the control strategy on the lateral stability of the double-trailer train, a dynamic model of the double trailer train (Type B double trailer) was built based on Trucksim simulation platform, which is a simplified reference model of Simulink double trailer train established according to the laws of mechanics. The yaw rate deviation and lateral load transfer rate deviation of each unit in the dynamic and reference model are taken as inputs respectively, based on fuzzy inference and PID (proportional-integral-derivative control) control theory. The active control strategy of vehicle yaw and roll stability is constructed, and the intervention time of control strategy is adjusted according to the result of vehicle state identification. The simulation results show that the active control strategy can significantly reduce the fluctuation amplitude of lateral stability evaluation parameters, and the peak value of the sideslip angle of each unit can be reduced by 5.7%∼53%, the yaw rate decreases by 4.9%∼23.8%, the roll angle decreases by 0.5%∼24.9%, and the lateral declination angle decreases by 0.3%∼32.9%. The results show that the control strategy designed in this paper can improve the lateral stability of the double trailer train, and the research results can provide a reference for the future study of the lateral vehicle stability of the double trailer train.



Rocking state analysis of nuclear power isolation structures under far and near field earthquakes

HE Wenfu, JI Min, REN Yifei, XU Hao, MIYAMA Takafumi

2024, 30(4):  595-607.  doi:10.12066/j.issn.1007-2861.2526

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This paper explored the various effects of far and near field earthquakes by investigating the rocking response and bearing states of nuclear power isolation structures under both far and near field vibrations. The influence of seismic characteristics on the structural swing response was discussed, including the swing angle of the superstructure, tension and compression stresses, and shear displacement of the isolation bearings. The swing angle of the superstructure increased linearly with an increase in the acceleration amplitude. Moreover, the swing angle of the superstructure caused by near field vibration was larger than that caused by far field vibration, with greater discreteness. When the acceleration amplitude was 1.2 g, the mean and standard difference of the swing angle of the superstructure caused by near field vibration could reach 2.88 times and 3.90 times those caused by far field vibration, respectively. Near field vibrations were more likely to cause the bearing to enter a state of unsteady deformation, and appear to be in a state of tension. This paper provided engineering reference values for the seismic isolation design of nuclear power structures.



Seismic reliability analysis of the curved surface sliding isolated structure under the stochastic ground motion

WANG Changhong, HU Shitao, HU Baolin

2024, 30(4):  608-621.  doi:10.12066/j.issn.1007-2861.2474

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Curved surface sliding isolated structures (CSSIS) is a new technology with wide application potentials. However, in engineering practice, the selection of seismic waves controls the seismic design and risk assessment of the CSSIS. A stochastic ground motion model that reflects specific earthquake characteristics was proposed, and the seismic reliability of the CSSIS was evaluated via Monte Carlo simulation (MCS). A mechanical model of the CSSIS was established, and the key structural parameters were determined via shaking-table tests and theoretical analysis. A random ground motion was generated using a stochastic method. Considering the Ninghe area in Tianjin as an example, the failure probability Pf of the CSSIS subjected to the first excursion criterion was calculated. The results show that earthquake magnitude M and source-to-site distance D significantly influence the seismic reliability of the CSSIS. As D increases, Pf of the superstructure decreases rapidly. Conversely, an increase in the earthquake magnitude M leads to an increase in Pf . The research results will provide an important design reference for the wide spread application of CSSIS.



Low carbon design of prefabricated shear wall structure

WANG Xinxin, ZHU Jiejiang

2024, 30(4):  622-634.  doi:10.12066/j.issn.1007-2861.2464

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A calculation model for carbon emissions from the physicochemical stage was built to establish an integrated carbon emission factor bank based on quotas. The objective function is the lowest carbon emission from the physicochemical stage of the fabricated shear wall structure, and the variables are the section size of the beam, wall thickness, wall length, and strength of the concrete wall. Considering the strength, building condition, and displacement constraint of the member, an optimization model is established using the optimization software Lingo, and the optimal size of the member and the strength of the concrete are determined. The feasibility of the optimization method is verified using a practical case study, which provides a reference for further promoting the development of prefabricated buildings in the design stage.



Consolidation drainage of compacted clay based on multistage direct-shear test

GAO Yu, ZHANG Yiming, DONG Yi

2024, 30(4):  635-643.  doi:10.12066/j.issn.1007-2861.2514

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Shear strength is an important mechanical parameter that determines the stability of soil and structures, such as foundations and slopes. Its value is generally obtained via direct-shear or triaxial tests. In these tests, three or four samples are typically used to measure the cohesion and internal friction angle of soil; the differences among samples will inevitably affect the accuracy of the results. Hence, this study improves the conventional direct-shear instrument so that it can be used to obtain the shear strength of a sample via repeated shears as well as the cohesion and internal friction angle of soil using the Mohr–Coulomb envelope. The results of multistage direct-shear tests for the consolidation drainage of compacted soil are compared with those of conventional direct-shear tests. The results show that the shear strength obtained from the multistage direct-shear test is slightly lower than that obtained from the conventional direct-shear test. Additionally, the error for the internal friction angle is ±2.5◦, which verifies that the multistage direct-shear scheme of consolidation drainage can be used to evaluate the shear strength of compacted soil.



Extraction process of soluble proteins from discarded tobacco leaves

SHA Yunfei, DU Huaiqing, XIONG Junwei, WANG Yangzhong, SHU Ruxin, CHEN Xu, DAI Xiaofeng

2024, 30(4):  644-654.  doi:10.12066/j.issn.1007-2861.2554

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This study innovatively combined ultrasonic extraction, ultrafiltration, and weakly alkaline isoelectric precipitation technologies to devise a process for the efficient ex-traction of soluble proteins from discarded tobacco leaves. Additionally, a comprehensive evaluation system incorporating physical, chemical, and biological parameters was established. By optimizing the process, an effective protocol was identified as follows. A pH 7.85 phosphate buffer at a concentration of 0.085 mol/L was utilized for ultrasonic ex-traction with a material-to-liquid ratio of 1∶8. Subsequently, fractionated centrifugation and filtration/ultrafiltration were performed, followed by adjustment of the solution to an isoelectric point pH of 5.5 using a 0.11 mol/L [H+] solution. This protocol facilitated the successful extraction of mixed proteins with molecular weights of approximately 55 kDa and exceeding 200 kDa. The amino-acid composition of the extracted proteins satisfied the essential amino-acid requirements of adults. Infrared-spectrum analysis indicated the absence of significant pectin or polysaccharide features. This research introduced a gentle,weakly alkaline isoelectric point extraction approach, combined with physical-extraction techniques. This method not only overcomes the limitations of conventional extraction processes but also exhibits broad applicability. Innovative pathways are presented herein for the resourceful utilization and industrial-scale production of discarded tobacco leaves.



Intent-extraction joint model with expertise integration

CHENG Feng, WAN Weibing, WANG Yuxuan, HU Jimi

2024, 30(4):  655-668.  doi:10.12066/j.issn.1007-2861.2548

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This paper proposed an intent-extraction joint model by fusing various expertise, which integrated knowledge graphs of vertical domains so that it could identify hidden information by understanding the user’s original intention. The relationship be-tween intent detection and slot filling was explicitly modeled, and the two were jointly trained to improve the overall performance of the model. The proposed model was evaluated on public datasets, Airline Travel Information System (ATIS) and The Snips Voice Platform (SNIPS), and the results yielded were superior to those of other intent detection models. Additionally, experiments were conducted on the constructed industrial quality traceability questions (QTQ) and product repair dataset (PR), where the proposed model yielded the best results. Specifically, the accuracy of intent detection on the QTQ dataset was 87.2%, the F1 value of slot filling was 86.7%, and the entire-sentence accuracy was 75.6%. Meanwhile, the accuracy of intent detection on the PR dataset was 92.5%, the F1 value of slot filling was 90.1%, and the entire-sentence accuracy was 88.5%, which indicated improvements to varying degrees compared with other mainstream models. Experiments showed that the proposed model could perform intent detection tasks with high accuracy and generalizability in industrial fields.



Light field image coding based on multi-feature fusion and geometry-aware networks

LIU Faguo, BAI Xiaoqi, ZHANG Qian, WANG Bin, SI Wen

2024, 30(4):  669-681.  doi:10.12066/j.issn.1007-2861.2546

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To address the inherent limitations of light field image coding methods relying on single parallax synthesis, which hinders the recovery of texture details from occluded regions, an innovative light field image coding approach grounded in multi-feature fusion and geometric perception networks is introduced in this research. The primary objective is to further enhance the compression performance of light-field images captured in occluded scenes. The methodology begins by employing sparse sampling of the dense light field, followed by the application of versatile video coding (VVC) to effectively compress the resulting sparse light field. Subsequently, two pivotal branch modules, the parallax estimation module and the spatial angle joint convolution module, were deployed during the decoding process. These branches collectively capture the global geometric attributes of the optical field image and ensure a more comprehensive recovery of the features, particularly from regions characterized by dense textures and occlusions. To exploit the structural information embedded within the fused features originating from these two branches fully, a stack structure featuring bidirectional views was constructed. Furthermore, a refinement network with geometric perception capabilities was used to reconstruct high-quality dense light fields. The experimental results demonstrate the significant advantages of our pro-posed method over current international light-field image coding techniques.



Using reconfigurable quaternary logic operators for constructing a configurable encryption technology for digital file encryption

WANG Hongjian, HAN Yichen, CHEN Xunlei, JIN Yi

2024, 30(4):  682-693.  doi:10.12066/j.issn.1007-2861.2561

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The universal circuit of reconfigurable quaternary-logic operators proposed in 2018 provides a core device for configurable encryption technology. A 32-bit configurable encryption device comprising an encryptor, decryptor, and a key derivation operator can be constructed on an area of approximately 1.6 thousandths of a square millimeter on a microchip. Within a 250 MB read-only memory, the source data for 1013 generalized keys can be preset, and each generalized key’s source data can configure the encryption device into a unique encryption system. These configured encryption systems can be sufficient for hundreds of years without reuse. The generalized key source data prestored in the configurable encryption device combined with reservation code technology can realize an utomatic change in the generalized key, thus avoiding any issues inherent in the memorization of keys. The security of the configurable encryption technology is high because of the one-time use of each generalized key. Because both the encryption and decryption processes are performed in hardware, the configurable encryption operation achieves a high speed. Furthermore, owing to the small size of the core circuitry and a memory capacity of only a few hundred megabytes, the configurable encryption device can be made as compact as a USB flash drive. Experimental tests demonstrated that the configurable encryption technology can implement block encryption on a variety of common digital files. It is theoretically speculated that the cipher text of this configurable encryption technology can resist various common attacks. Therefore, this technology has good application prospects.



Extrapolation methods for accelerating LeaderRank

WANG Ke, MU Xuejie, XU Xinjian

2024, 30(4):  694-703.  doi:10.12066/j.issn.1007-2861.2478

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Identifying vital nodes in complex networks is important for investigating net-work structures and their corresponding propagation processes. LeaderRank, as an algorithm for ranking the nodes of complex networks, has been widely applied in various fields. Based on the power method, this study proposes three methods for accelerating the computation of LeaderRank, i.e., the Aitken extrapolation method, the power extrapolation method, and the modified version of the latter. Experiments on the dataset of four real networks show that the Aitken extrapolation method is faster than the power extrapolation method, albeit with a lower precision, and that the modified power extrapolation method provides good balance between accuracy and speed.



Steady-state perching modeling and grasping leg/claw design of bionic raptor robot

XU Yong, GUO Shuyan, WEI Xinmei

2024, 30(4):  704-720.  doi:10.12066/j.issn.1007-2861.2564

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To solve the limitations in the abilities of aerial robots with legs/claws in grasping and perching on complex objects, a bionic raptor robot that can be integrated with a robot body and has the ability to reliably grasp and maintain stable perching in unstructured environments was presented in this paper. In this study, a steady-state perching model of a robot was established, and the optimal leg sizes with the minimum overturning moment were obtained. Angular momentum and linear momentum models of the robot were established, and a successful perching parameter domain satisfying the overturning moment and momentum constraints, which were generated by a combination of the three-dimensional parameters of the centroid velocity angle, centroid velocity, and leg angle, was obtained. A pair of under-actuated grasping legs/claws was designed to passively transform instantaneous impact energy into a strong grasping force and passively maintain a reliable grasping state by self-locking. In the perching experiments and perching motion simulations of this robot prototype, the kinematic parameters changed consistently and steadily. The above achievements confirm the rationality of the steady-state perching model, momentum model, and robot structural design scheme proposed in this study and lay theoretical and methodological foundations for the subsequent realization of the real-time position control of a bionic raptor perching robot and its wide applications in remote sensing, search and rescue, and environmental monitoring in unstructured environments.



Preparation and electromagnetic interference properties of GO modified C/C composites

NING Lixin, CHEN Zechao, HONG Jianting, WANG Xu, PENG Yuqing, ZHANG Fangzhou, WU Yifeng, LIU Liqi

2024, 30(4):  721-732.  doi:10.12066/j.issn.1007-2861.2531

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In order to obtain a simple and low-cost electromagnetic shielding material, the 2D carbon fiber (CF) precast was loaded with graphene oxide (GO) by spraying method, and the boron-phenolic resin (BPF) was used as the precursor, and the graphene supported carbon fiber (GO/CF) was used as the precast. GO modified carbon/carbon composites (GO/C/C) were prepared by hot press molding method and carbonization process. X-ray Diffraction (XRD), scanning electron microscope (SEM), Raman spectrum, densitometer and vector network analyzer were used to characterize the composites. The results show that the surface morphology of GO/CF preform is the best when the load of GO is 0.1% and 0.3%. When GO content is 0.3%, the composites have the highest porosity and the lowest resistivity. When the load of GO is 0.1%, the total electromagnetic shielding efficiency of the composite in the X-band is the highest, reaching 43.84 dB, which is 28.3%higher than that of the blank sample, and has met the basic commercial requirements.



High-precision Roothaan-Hartree-Fock calculation method for atomic ground state energy

LI Yongle, GUI Xiongfei, GAO Heng, REN Wei

2024, 30(4):  732-740.  doi:10.12066/j.issn.1007-2861.2412

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The Roothaan-Hartree-Fock (R-H-F) approximation in quantum mechanics plays an important role in the calculation of the electronic structure of atoms, molecules and materials, and is the basis for other high-precision electronic structure calculation methods. Based on the rich basis set resources in the open-source website Basis Set Exchange, this paper uses the characteristics of the analytic expression of the Gaussian basis set matrix elements, and the in-house Roothaan-Hartree-Fock computer program, to easily achieve high-precision calculation results. The ground state energies of various atoms and ions are calculated with basis sets of different sizes, and it is found that with the increase of the number of basis functions, different types of basis sets exhibit different convergence properties. Furthermore, using the self-written R-H-F program, this work calculated the first ionization energies of He, Be, and Ne, with a maximum error of 6.84 percent compared to the experiment.



Band-gap soliton transport

CHENG Lu, CHEN Yuanyuan

2024, 30(4):  741-750.  doi:10.12066/j.issn.1007-2861.2334

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In nonlinear periodic systems, the relation between nonlinearity and dispersion can generate spatially localized band-gap solitons. One of the outstanding features of these solitons is that they are practically immobile. In this study, we propose a means of spatially moving band-gap solitons through the periodic modulation of periodic potentials. We first numerically identify stable band-gap solitons, then set them as initial states and allow them to evolve with the modulation of the relevant phases of periodic potentials. We find that if the modulation is sufficiently slow, the band-gap solitons can be transported away at a very high fidelity. This work provides a possible theoretical scheme for transporting band-gap solitons.



First principles calculation of photoelectric response in GaAs nanojunctions

CAO Rui, CHEN Jingzhe

2024, 30(4):  751-757.  doi:10.12066/j.issn.1007-2861.2414

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As a direct bandgap semiconductor with high electron mobility, GaAs and its photoelectric response have been the focus of academic researches. Macroscopic finite element methods combined with semi-classical theory are normally used to simulate the photoelectric response of semiconductor devices with specific structures. With the miniaturization of devices, the microscopic structural features become more important. In this paper, the non-equilibrium Green’s function method with density functional theory(NEGF-DFT) was firstly adopted to calculate the light response of GaAs nanojunctions under chemical doping and gate voltage, and qualitative analysis of the doping density on light response is achieved. This work casts light on the first-principle analysis of photoelectric response of semiconductor devices and will be meaningful to the future researches in this field.



Fast and robust magnetization dynamics control of ferromagnetic thin films

LI Xinhe, BAN Yue

2024, 30(4):  758-768.  doi:10.12066/j.issn.1007-2861.2339

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A fast control protocol for magnetization dynamics of submicron ferromagnetic thin films is proposed. Because of spin-orbit coupling, the spin-polarized current generated by the external electric field induces magnetization rotation in the local magnetic moment of the ferromagnetic layer via s-d exchange coupling. We apply an inverse engineering method, a shortcuts to adiabaticity technique, to flip the magnetization orientation in the submicron ferromagnetic thin films and optimise the intensity of the electric field. We also analyze the control schemes for ferromagnetic thin films with both isotropic and anisotropic shapes. Our proposed protocol can shorten the reversal time of the magnetization vector compared to that of the existing methods by an order of magnitude and exhibits better robustness.



Fast splitting of ultracold atom based on variational approach

ZHANG Jia, HAO Minjia, CHEN Xi

2024, 30(4):  769-776.  doi:10.12066/j.issn.1007-2861.2417

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Shortcuts to adiabaticity can speed up an adiabatic process along a nonadia-batic route. Inspired by the shortcuts to adiabaticity, in this paper we propose a method for fast and stable splitting of atom in a double well based on ultracold atomic interferometers. Specifically, we firstly apply the variational approximation approach to solve the Gross-Pitaevskii (GP) equation in the mean-field approximation theory to derive the dynamic equation of the Bose-Einstein condensation. Then we use the inverse engineering to design the frequency of external potential, which enables fast splitting of ultracold atom in a shorter time. And this method avoids the final excitation.