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  • Yu-fei YANG, Yong-qi LU, Ting-ting LIU, Si-qi XU, Rui-xiao HUANG, Qing-qi DIE
    Science Technology and Engineering. 2025, 25(13): 5285-5296.

    Long-term stockpiling of coal fly ash releases a large amount of toxic and hazardous substances, posing a threat to the soil and water environment. In order to have a comprehensive understanding of the research progress in this field, a bibliometric method was conducted to systematically and deeply visualize and analyze the relevant literature in CNKI and Web of Science databases from the period of database construction to 2023. The results show that the annual total number of publications in this field is generally on the rise. Among them, Chinese scientists have conducted a substantial amount of research in this field, accounting for the highest publication volume, which makes up 18.87% of the total, providing important scientific foundation for subsequent studies. The betweenness centrality of publications from the United States (0.51) is significantly higher than that of other countries, and its research results have greater international influence. The research hotspots focus on contaminants like heavy metals in coal fly ash, investigating their leaching and release patterns under various conditions, and revealing the environmental impacts of contaminants migration from coal fly ash landfills. Based on high-frequency keyword analysis, the composition of contaminants in coal fly ash and the types of contaminants potentially released into the water environment were examined. A systematic review and analysis of contaminants release mechanisms, release regularity, key influencing factors, and the migration regularity of mechanisms in environmental media were conducted. Future research should further focus on the release of heavy metals such as Pb, Cr, and Hg, trace elements like As, Se, and Mo, and specific mechanisms such as F-, Cl-, and $\mathrm{SO^{2-}_{4}}$, $\mathrm{PO^{3-}_{4}}$ during the coal fly ash stockpiling. Studies should explore the release characteristics of these mechanisms under complex environmental conditions, investigate whether synergistic or inhibitory mechanisms exist between various factors, and establish quantitative relationships between mechanisms indicators in the solid phase of coal fly ash and their release into water environment. This will provide a theoretical basis for scientifically evaluating the environmental impacts of coal fly ash and effectively preventing potential threats to water environment.

  • Qin-chao YANG, Li ZHANG, Lu-xing DOU, Hong-ping LIU
    Science Technology and Engineering. 2025, 25(13): 5316-5329.

    Seasonal deltas are deltaic sedimentary systems controlled by seasonal rivers in continental basins. Modern seasonal deltas are mainly developed in arid and semi-arid climate with gentle topography. However, the study on the sedimentary model of seasonal deltas in ancient sedimentary records is still insufficient. Suweiyi Formation in Tabei area, Tarim Basin was selected as the research object. Based on 63 logging data and 215.52 m core data in the study area, logging facies templates of different sedimentary microfacies and lithofacies type combination templates were established, and the vertical evolution law of sedimentary facies plane characteristics was analyzed and summarized, and the overall sedimentary model of the study area was established. The results show that the Suweiyi Formation in Tabei area developed 4 categories and 17 subtypes of rock facies. During the depositional period of the lower Suweiyi Member, seasonal shallow water braided river deltas were developed in the study area. A seasonal shallow meandering river delta with multiple flood events and retrograde accumulation developed in the north of the study area during the sedimentary period of the upper Suweiyi Member. Finally, the profile and single well sedimentary model of seasonal shallow water delta affected by factors such as accommodable space, frequent change of sedimentary base level and sudden events were established. The results provide a reference for further understanding of the seasonal shallow water delta depositional model under the background of arid climate, and also provide geological basis for lithologic trap exploration.

  • Yu GUO, Shi-ming CHENG, Yang LI, Xiao-lei LIU
    Science Technology and Engineering. 2025, 25(13): 5351-5358.

    Recently, the vessel-shaped aquacultural farm has received much attention from the academia and industry because of its importance in promotion and sustainability of marine fishery. Polluted surroundings unsuitable for fish growth are always introduced by traditional multiple point mooring system. Therefore, single point mooring system is more suitable for the aquacultural farm. In recent years, mooring scheme optimization and performance assessment was frequently investigated in most existing literature, while studies on design of the single point mooring system are rare. Based on the requirement of reducing hull reconstruction, an external turret single point mooring system was proposed, which is composed of the turret device, the mooring anchor, the truss structure and the bearings. And their working principle were also clearly illustrated. Then, three dimensional potential theory was applied to obtain the hydrodynamic coefficients of the ship by use of the software AQWA. Finally, in order to verify the positioning ability of the mooring system under both operational and survival conditions, the direction of wind, wave and current was combined according to the rules, and time-domain coupling analysis of the farm-mooring system was carried out. From the numerical results, it can be seen that yaw, relatively large sway and roll motions will be induced due to different direction of the wind, current and wave. The mooring line tension is adequate and safe under all conditions, indicating that this proposed single point mooring system exhibits good positioning performance.

  • Fang-hao ZHANG, Jian-zhong LI, Er-lei GONG, Qian YAO, Ren-chuan ZHENG
    Science Technology and Engineering. 2025, 25(13): 5671-5680.

    In order to reveal the unsteady flow characteristics during the pre-compression process of the radial wave rotor combustor, the pre-compression mechanism induced by complex wave systems under typical operating conditions was simulated and analyzed using three-dimensional unsteady simulations. The impact of pressure differential across intake and exhaust ports, as well as rotor speed, on the propagation behavior of compression waves within the channels was focused on. The results indicate that as compression waves propagate within the channels, they are influenced by the curvature of the curved channels, leading to wave reflection, refraction, and attenuation. This results in energy loss and waveform distortion, which affect the propagation path and speed of the compression waves. Although a higher pressure difference enhances the intensity of the compression waves, it exacerbates overfilling of the fuel and flow instability, increases thermodynamic losses, and significantly reduces the isentropic compression efficiency. The rotational speed affects the propagation characteristics of compression waves within the channels by adjusting the operational timing of the wave rotor. At 1 200 r/min, the opening time of the intake port is extended, causing the compression waves to reflect and form expansion waves that propagate in the reverse direction. This results in a pressure ratio within the channel of only 103% and a substantial decrease in isentropic compression efficiency.

  • Yun-guang WEI, Guo-lin LIU, Feng-yun WANG, Hu-zhen HE
    Science Technology and Engineering. 2025, 25(13): 5305-5315.

    On December 18, 2023, a MS6.2 earthquake occurred in Jishishan County, Gansu Province, marking the largest earthquake recorded in the area since seismic observations began. To investigate the practical application of interferometry synthetic aperture radar(InSAR) technology in monitoring surface deformation in Jishishan County and its surrounding areas before and after the earthquake, 13 C-band Sentinel-1A SAR images covering the earthquake event and study area were utilized. D-InSAR and SBAS-InSAR techniques were employed to process the data, obtaining surface deformation information along the radar line of sight before and after the earthquake, and a comparative analysis of the deformation rates before and after the event was conducted. The results show that the monitoring results of the two techniques show a bulge phenomenon centered in Liugou Township (the epicenter), which gradually expands outward in an elliptical shape, and then evolves into irregular subsidence. The maximum line-in-line shape variables before and after the earthquake are 41 mm and 16 mm, respectively. The overall deformation of the whole region after the earthquake is relatively stable, which is consistent with the relevant data. The D-InSAR and SBAS-InSAR technologies can be used to monitor the long-term surface deformation process and abnormal conditions before and after earthquakes, and provide effective support for quickly obtaining the distribution range of coseismic geological disasters and guiding post-earthquake emergency rescue and post-disaster recovery and reconstruction.

  • Jun-hai AN, Yan-hua ZHANG, Qiao-feng LIU, Xue-hui ZHANG
    Science Technology and Engineering. 2025, 25(12): 5128-5140.

    In order to study the applicability of the assembled subway station structure in the liquefiable site of the seismic fortification area, based on the engineering practice of Shuangfeng Station of Changchun Metro, the seismic response analysis of the assembled subway station structure in the liquefiable stratum was carried out by using the finite difference software FLAC3D. Compared with the calculation results of the corresponding cast-in-place subway station conditions, the pore water pressure of the foundation, the dynamic response and floating characteristics of the subway station structure and the deformation characteristics of the assembled subway station structure were studied. The results show that, similar to the calculation condition of cast-in-place underground structure, in the calculation condition of assembled subway station in liquefiable site, the pore pressure ratio of site soil shows three stages: initial slow increase stage, middle rapid increase stage and final gentle stage. When the seismic intensity is high, the underground structure has a significant inhibitory effect on the liquefaction of the surrounding soil. The acceleration response of the prefabricated station structure is smaller than that of the cast-in-place structure, which reflects its flexible adaptation to the deformation of the terrain in the liquefiable site. The connection between the side wall and the middle plate is the key part of structural strength control. When the intensity of the input ground motion is low, the vertical displacement changes of the structure are manifested at different positions of the bottom plate show the development stage of a small amount of sinking at the beginning, then a sharp rise, and finally a downward trend, but with the increase of the intensity of the ground motion, this phenomenon is gradually not obvious. The deformation of the assembled subway station structure under horizontal ground motion is closer to the shear deformation. Its flexible connection is easier to adapt to the larger vertical relative deformation than the rigid connection of the cast-in-place station, and its anti-overturning ability is better.

  • Yang-yang QU, Tao LI, Wang-shui HU, Yang ZHANG
    Science Technology and Engineering. 2025, 25(12): 4957-4966.

    The evolution of submarine channels and their sedimentary units under a million-year scale is related to factors such as sediment supply, sea-level change, paleotopography and tectonic movements. However, the changing rate of sea level has not been deeply associated with the type, scale, and sand-body distribution of submarine channels and their surrounding sedimentary units. Taking the central Oligocene submarine channel in the northern Atlantic basin as an example, based on three-dimensional seismic data cube, seismic-facies characteristics of submarine channels with their sedimentary units were characterized. 90°-phasing transformation and stratal slicing techniques were used to depict the planar distribution of submarine channel with sedimentary units. Frequency spectral decomposition was used to analyze the evolution of sedimentary units and the distribution of sand bodies. The sedimentary model of submarine channels with changing rate of sea level at a million-year scale was established. The results indicate that from the early to late Oligocene, a composite system of sandy submarine channel-terminal fan, a composite system of sandy-muddy filled submarine channel-crevasse fan and a composite system of muddy submarine channel are developed in sequence. The mass transport deposits are always accompanied. Sedimentary evolution process is mainly controlled by global sea level and can be divided into a slow sea-level dropping period of early Oligocene, a rapid sea-level rise period of middle Oligocene and a rapid sea-level dropping period of late Oligocene. The slow sea-level fall is conducive to the transportation of coarse terrestrial clastics through submarine channels into the oceanic basin, which is an important prerequisite for the formation of sandy submarine channels, terminal fans and large associated mass transport deposits. Therefore, sand bodies are most developed in the lower Oligocene.

  • Kun-long FAN, Sheng-hai WANG, Jian-chao QIU, An-qi NIU, Wei-han QIU, Hai-quan CHEN
    Science Technology and Engineering. 2025, 25(12): 5209-5217.

    Due to the complexity and variability of the marine environment as well as the complexity of the dynamic characteristics of the offshore stabilized corridor bridge in a series-parallel hybrid configuration, the analysis of the dynamic characteristics of the offshore stabilized corridor bridge in the working process has always been a key point and a difficult point in the related research process. To address this problem, firstly, the projection matrix and Jacobi matrix of each component of the bridge were derived based on the vector method and Kane's method, as well as the dynamic equations under the generalized coordinate system, and the overall explicit dynamics model of the bridge was derived by using the Kane's method and the principle of virtual work. Secondly, a joint simulation model of MATLAB and Adams was constructed based on Simulink and the simulated motion of the vessel was simulated by the MSS toolbox to simulate the ship's motion as an excitation for analysis. Finally, theoretical calculations and simulation analysis were carried out under two working conditions, with and without personnel and cargo transfer, to verify the correctness of the established model. Further, the effects of loads of different masses on the driving force of the strut chain were investigated, and the compensating effect of the sea-stabilised corridor bridge was analysed. The research results are of guiding significance for the development of the sea-stabilised corridor bridge and its application on real ships.

  • Ai-lin ZHANG, Kai WANG, Chao DING, Ze-wen YAN, Xiu-ying LANG
    Science Technology and Engineering. 2025, 25(12): 5058-5065.

    Aiming at the issue of how to realize the dynamic updating of the digital twin model of historic buildings, a “build-compare-update” updating idea was proposed. Firstly, the shape distribution method was used to draw the shape distribution curve of the digital twin model of the historical building at different time points, based on completing the construction of the digital twin model of the historical building. Secondly, the mean absolute error method was used to assess the similarity of the two models. Furthermore, according to the results of the similarity assessment, the updating strategy for the model of the components of the historic building was set up and the updating of the digital twin model was completed with the help of relevant software. Finally, to validate the design, the arch column component of the Jade Buddha Hall of Hongci Temple was used as a case study. The results show that the proposed idea of updating the historical building model and its implementation method not only lay the foundation for realizing the dynamic updating of the digital twin model of historical buildings, but also provide reference value for the intelligent protection of historical buildings.

  • Quan ZHANG, Jing-song GE, Nan LI, Hui-juan NIE, Xiao-ying LI
    Science Technology and Engineering. 2025, 25(12): 5151-5163.

    Cultural relics protection units are important carriers of Chinese outstanding traditional culture. It is of great significance to study the spatial differentiation of cultural relics protection units and the differences in the results of multi-scale driving factors, in order to continuously promote the inheritance of history and culture, and to prosper the development of regional cultural undertakings and cultural industries. Huizhou cultural relics protection units were taken as the research object, and standard deviation ellipse, kernel density estimation and geographic detector methods were used in the analysis of spatial and temporal differentiation and driving factors of cultural relics protection units. The results show that the cultural heritage units in Huizhou region present the time series characteristics of “dispersed-concentrated-dispersed”, and the center of distribution gradually shifts from the middle to the south. The spatial aggregation of cultural heritage units is remarkable, the overall performance of the “V” distribution pattern, specifically concentrated in Shexian County and Jixi County. Natural geographic factors and human geographic factors have an impact on the spatial differentiation of cultural heritage units.