International Core Journal of Engineering
International Core Journal of Engineering is an international journal to promote all fields of Engineering, it considers original and timely contributions containing new results in mechanical engineering, electrical engineering, civil engineering, chemical engineering, etc. All articles published are rigorously and fast reviewed meeting the Journal Quality standards.
A Two-Stage Pre-Positioning Method for Resolver Zero-Offset Calibration in PMSM
High-performance control of Permanent Magnet Synchronous Motors (PMSMs) heavily relies on accurate rotor position information. However, the inherent zero-offset error in resolvers can lead to controller output disturbances and even induce significant safety hazards such as system shutdown. Therefore, this paper designs and implements a detection strategy for the zero-offset angle suitable for zero and low-speed operating conditions. To overcome the dead-zone issue in single pre-positioning at a power angle of π-where zero electromagnetic torque prevents rotor movement-a "two-stage pre-positioning" correction method is proposed. This approach implements an open-loop angle injection strategy. First, a 0° virtual angle and quadrature-axis current are injected for initial positioning. Then, the virtual angle steps to 90°, triggering a second positioning. This instantaneous 90° commutation of the stator field generates maximum transient torque, overcoming static friction and load torque to precisely align the rotor. Experiments validate that the proposed two-stage pre-positioning method safely and rapidly aligns the rotor to a determined position, enabling the acquisition of the actual zero-offset angle.
PMSM; Zero-Offset Angle; Two-Stage Pre-Positioning.
Copyright (c) 2026 International Core Journal of Engineering https://creativecommons.org/licenses/by-nc/4.0
Numerical Analysis of Buried Pipeline under Land Subsidence Action
Buried pipelines operate in complex environments, where factors such as non-uniform soil settlement and corrosion from surrounding substances can alter their stress state, potentially leading to pipeline failure and subsequent accidents. To tackle these challenges, a finite element model was developed using ABAQUS to simulate the coupled pipe-soil interaction under ground subsidence conditions. With emphasis on the settlement behavior of an intact pipeline, numerical investigations were conducted to identify the threshold of pipe-soil coordinated deformation and to characterize the evolution of Mises stress distributions throughout the final settlement phase. Based on this, the Mises stress variations in the pipeline were compared at soil settlements of 0.22 m and 0.5 m. The findings reveal that the maximum Mises stress occurs in the vicinity of the settlement interface and moves progressively farther from this boundary as the degree of settlement increases, accompanied by an overall elevation in pipeline stress. On the left side of the interface, tensile stresses develop at the pipe crown, whereas on the right side, tension is observed at the pipe invert; in both cases, the tensile-side stresses remain consistently higher than their compressive counterparts. These findings can provide a basis for the protection of buried pipelines.
Buried Pipeline; Corrosion Defects; Nonuniform Settlement; Loca Stress.
Inter-Module Connections and Global Structural Behavior of Modular Steel Buildings: A Review
Modular steel buildings are mainly constructed through factory prefabrication and on-site assembly. Their global structural performance is governed to a large extent by inter-module connections. Existing studies have shown that local nonlinear behaviors in connections, such as gap closure, frictional slip, semi-rigid rotation, and cyclic degradation, can be amplified into global structural effects through load-path reconfiguration and deformation compatibility. These effects include the redistribution of inter-story drift, the accumulation of residual deformation, and the formation of weak stories. As a result, they can influence seismic and wind-resistant design outcomes as well as structural robustness assessment. This paper reviews the structural forms and load-transfer mechanisms of inter-module connections in modular steel buildings. Experimental and numerical evidence on global structural behavior is systematically summarized. A performance evaluation framework oriented toward global response is then outlined, together with approaches for describing system-level coupling effects. The development of equivalent connection modeling and global analysis methods is also reviewed. Finally, research prospects are discussed from the perspectives of high-rise development, performance-based design, reparability, and robustness. The study aims to provide reference for engineering design and standardized application of modular steel buildings.
Modular Steel Buildings; Inter-Module Connections; Global Structural Behavior; Performance Evaluation.
Dynamic Optimization Design of the Base Plate Structure of a Track Inspection Robot based on Modal Analysis
The detection accuracy of track-based inspection robots is directly related to the smoothness of equipment operation on the track. Harmful vibrations caused by defects in the dynamic characteristics of the equipment structure are the fundamental reason for blurred monitoring images and distorted data. Addressing the issue of insufficient rigidity in the load-bearing base plate of a certain type of track-based inspection robot, this paper conducts analysis and parameter optimization based on the resonance risk induced by dense low-frequency modes. The parameterized finite element model, after simulation analysis using the Constrained Modal Analysis tool, reveals that the original structure's 3rd-order natural frequency within the narrow frequency band from 90 Hz to 102.60 Hz highly overlaps and is densely distributed with the drive system's second harmonic excitation frequency band from 90 Hz to 110 Hz. The same frequency can cause equipment resonance and pose a hazard to reliability. Modal analysis of the optimized structure shows significant improvement in the dynamic performance of the equipment structure, with the fundamental frequency increasing from 99.60 Hz to 186.58 Hz (an increase of 87.3%). The original dense mode group is effectively separated, the distribution of frequencies at various orders tends to be reasonable, and the natural frequencies are all migrated to the safe frequency band, resolving the resonance risk from the source. Although the optimized model weighs 0.9 kg more (an increase of 36.3%), the resulting improvement in dynamic performance is more significant. This study verifies the effectiveness of the structural dynamic design optimization method based on modal analysis, providing a reference for early risk prediction and design iteration of similar equipment.
Modal Analysis; Structural Optimization; Inspection Robot; Natural Frequency; Resonance; Finite Element Simulation.
Fatigue Life Analysis of Welded Joints in Spigot-and-Socket Connections for Arch-Beam Structures
Using finite element numerical simulation, the influence of wind load on the fatigue life of welded joints in spigot-and-socket connections of arch-beam structures was investigated. Two methods were employed: the nominal stress method specified in the Chinese steel structure design standard GB 50017-2017, and the hot-spot stress method based on extrapolation as prescribed in the IIW (International Institute of Welding) documents XIII-1539-96/XV-845-96. The results indicate that the fatigue life predicted by the hot-spot stress method is longer than that obtained from the nominal stress method. Consequently, fatigue analysis based on the nominal stress method yields more conservative results. However, compared with the nominal stress approach, the hot-spot stress method demonstrates better integration with numerical simulation.
Numerical Simulation; Weld Fatigue; Nominal Stress; Hot-Spot Stress.
Application of MOF Material Modification Strategy in Electrolysis of Water
As a key component of sustainable hydrogen production technology, electrocatalytic water decomposition has promoted the development of various catalysts. Metal organic frameworks (MOFs) have become potential candidate catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). However, MOFs materials face challenges related to stability, conductivity and scalability. This review systematically summarizes the basic chemical reactions and reaction mechanisms of electrolytic water reaction, deeply analyzes the application of MOFs materials in electrolytic water, and finally puts forward suggestions for the structural modification strategy of MOFs materials in the future.
MOFs Materials; Electrolytic Water; Material Modification.
Research on PMSM Speed Control of Rotary Steerable System based on Modified LADRC
In response to the complex working conditions of the permanent magnet synchronous motor in the rotary steerable system under multiple sources of disturbance, the traditional Linear Active Disturbance Rejection Control(LADRC) has a large observation burden, hysteresis, and low accuracy due to significant load changes, which affects the adjustment of the drilling tool face angle and trajectory stability. Based on the permanent magnet synchronous motor (PMSM) speed current dual closed-loop vector control system, this paper introduces a disturbance observer to optimize the observation mechanism on the basis of the speed loop LADRC, and proposes an modified LADRC(MLADRC) speed control strategy.A simulation model of underground PMSM speed regulation was built in MATLAB/Simulink, and a comparative simulation was carried out under the conditions of speed step and load sudden changes of different amplitudes. The results showed that the designed disturbance observer could accurately capture load torque sudden changes. MLADRC achieved 0 overshoot under speed step and steady-state error control within ±1RPM. During load sudden changes of 5N·m and 15N·m, the speed fluctuation was smaller, the recovery time was shorter, and the anti-interference performance was better, which is suitable for underground load fluctuation scenarios.The MLADRC proposed in this article effectively solves the observation lag problem of traditional LADRC, providing a feasible solution for the optimization of PMSM speed regulation and the improvement of drilling trajectory stability in rotary directional drilling systems.
Rotary Steerable System; Permanent Magnet Synchronous Motor; Linear Active Disturbance Rejection Control; Disturbance Observer.
Near-Infrared Self-Powered Photodetector based on Graphene/Si Heterojunction
High-performance self-powered infrared photodetectors that operate without consuming external power are of great significance for applications in optical communication, sensing, and motion detection. Herein, we constructed a vertical Graphene/Si heterojunction. Benefiting from the structural design and interface purification, the device exhibits a significantly enhanced self-powered photocurrent response and near-infrared detection capability. It demonstrates a responsivity of 5.55 A/W and a specific detectivity of 4.62 × 1012 Jones at 808 nm, along with a fast response time of 5.5/7.2 μs. Furthermore, the device retains its performance without degradation after 200 days, exhibiting stable temporal response characteristics and long-term repeatability. These results suggest that this heterostructure provides an effective strategy for high-performance self-powered infrared photodetectors.
Graphene/Si Heterojunction; Self-Powered; Near-Infrared Photodetection.
Power Battery Recycling Path Planning Considering Risk and Priority Scheduling
As power batteries from new energy vehicles reach retirement, the need for efficient and safe recycling is becoming urgent. Existing studies often focus on cost and transport efficiency, while risks such as leakage and explosion, and inefficiencies from small-scale, fragmented collections, are overlooked. This study proposes a priority-based scheduling strategy that classifies recycling tasks into emergency and normal levels based on inventory thresholds and storage duration. A mixed-integer programming model is developed, integrating constraints like minimum load limits and urban traffic peaks. The model is validated in five simulated scenarios. Results show a 100% task completion rate and vehicle load factors ranging from 92.4% to 97.9%. In emergency-heavy cases, the priority mechanism improves efficiency significantly. These findings highlight the model’s role in enhancing reliability and mitigating risk, offering useful insights for optimizing battery recycling and guiding hazardous waste transport policy.
Power Vehicle; Reverse Logistics; Route Optimisation; Priority.
Logging Evaluation Methods for Irreducible Water Saturation in Tight High-Water-Cut Gas Reservoirs: A Case Study of the Dongsheng Gas Field in the Ordos Basin
As a crucial parameter for the evaluation and development decision-making of high-water-cut tight sandstone gas reservoirs, irreducible water saturation (Swi) plays a decisive role in reservoir productivity assessment and development plan design. However, traditional determination methods such as the existing core mercury injection experiment and nuclear magnetic resonance (NMR) logging inversion suffer from high costs, long cycles, and low coverage, which severely restrict gas reservoir development decisions. Taking the high-water-cut tight sandstone gas reservoir in the Dongsheng Gas Field of the Ordos Basin as an example, this paper proposes a new low-cost and continuous prediction method based on conventional logging data and the Random Forest (RF) machine learning algorithm. Through logging sensitivity analysis, the pore structure index (PSI) and density-neutron difference were introduced, and combined with the Random Forest algorithm, 5 sensitive parameters (GR, PERM, PSI, AC, DEN) were selected. Using the Swi calculated from the NMR logging T2 spectrum of 1,135 sets in 18 wells as the true value, a prediction model was constructed. For the test set of the model, the coefficient of determination (R²) is greater than 0.9, and the mean absolute error (MAE) is less than 0.05, indicating reliable generalization ability. The prediction results of this method in Well A of the Dongsheng Gas Field are highly consistent with the NMR resultsThis method can realize continuous evaluation of the entire well section, significantly reduce the reliance on special logging and associated costs, and provide technical support for low-cost and high-precision reservoir evaluation of tight gas reservoirs in the gas field.
Irreducible Water Saturation; Conventional Logging; Machine Learning Model.
Overview of Research Methods for Shear Lag Effect of LVL-UHPC Composite Box Girder
In the development and application of bridges, box section is the most common section used in bridges, mainly because the box section bridge has good mechanical performance and stiffness. Although the good mechanical performance of box girder structure is outstanding, it must be considered in the design of engineering structure because of the existence of shear lag. Otherwise, it is easy to have safety accidents, and many accidents of tube structures and bridges are caused by shear lag. Therefore, strengthening the research on shear lag of box-section structural system is not only the need of the development of civil engineering analysis theory, but also has important practical significance and application value.
Box Girder; Shear Lag Effect; Theoretical Analytical Method; Numerical Simulation; Experimental Investigation.
Three-Degree-of-Freedom Semi-Active Seat Suspension System based on Magnetorheological Dampers
In this study, the parameters of the Bouc-Wen model were identified using Particle Swarm Optimization (PSO) based on experimental data regarding the damping characteristics of magnetorheological (MR) dampers. By analyzing the dynamic characteristics of seat suspension systems, a three-degree-of-freedom (3-DOF) semi-active seat suspension model was developed. To overcome the inherent limitations of traditional passive suspensions in adapting to diverse road conditions, a semi-active suspension system was designed. Numerical simulations were subsequently conducted to evaluate the dynamic performance of both passive and semi-active suspension systems under random road excitation. The comparative analysis demonstrates that the proposed semi-active seat suspension significantly outperforms the passive system in vibration mitigation.
Intelligent Magnetorheological Materials; Bouc-Wen Simulation Model; Three-degree-of-freedom (3-DOF) Seat Suspension; Vibration Reduction.
Spatio-Temporal Case Study of Carbon Emissions and Balance in a County of Shaanxi Province
Global warming has heightened concerns about carbon emissions, prompting China to implement the “Dual Carbon” strategy. As pivotal connectors between urban and rural areas, counties’ carbon emissions research is essential for green, low-carbon development. this study investigates the spatiotemporal patterns of county-level carbon emissions from 2006 to 2021 using nighttime light data and carbon emission statistics. Standard deviation ellipse analysis reveals a steady southeastward shift of the emission center and a near doubling of emissions over the study period. Based on a “Production-Living-Ecological” spaces(PLES) land-use framework, the study evaluates 2021 emissions and applies the Ecological Support Coefficient (ESC) to analyze the spatial distribution of carbon balance. Results show that industry and tourism are the main emission sources, with major carbon sources in the east and sinks concentrated in the northeast. To meet “Dual Carbon” goals, counties should reduce emissions from key sectors and strengthen carbon sink protection to support low-carbon development.
County-level Carbon Emissions; Nighttime Light Data; Spatial Pattern;
Research on Hull Design and Path Planning of Unmanned Garbage Collection Boats in Small Water Areas
With the acceleration of urbanization, the pollution problem caused by floating debris on the water surface of small water areas such as artificial lakes in parks and landscape water systems has become increasingly prominent. Meanwhile, the traditional manual cleaning methods suffer from low efficiency and high costs. To address this issue, this paper develops a catamaran-type unmanned surface vessel (USV) for garbage collection, which is suitable for small enclosed water areas, and focuses its research on the hull design and path planning of the USV. This paper constructs a set of regional full-coverage path planning methods, which provides algorithmic support for the comprehensive cleaning of water surface garbage. Simulations are carried out on MATLAB, and prototype experimental verification is completed, thus designing an effective path planning scheme for USVs to perform garbage collection tasks in small water areas.
Unmanned Ship; Hull Design; Path Planning; MATLAB.
Design and Implementation of a Laser Combat Smart Car Integrating Target Tracking and Obstacle Avoidance
Laser combat tasks require high dynamic target-tracking accuracy, fast real-time response, and reliable obstacle-avoidance capability in complex environments. However, in conventional intelligent vehicle systems, coordination among target tracking, motion control, and obstacle-avoidance decision-making is often degraded by response delays and control conflicts, thereby reducing pointing stability and task completion rate. To address these issues, a laser combat smart car system integrating target tracking and obstacle avoidance was designed and implemented. A hierarchical cooperative architecture based on a Raspberry Pi 5B and an STM32F407 was adopted: grayscale preprocessing was performed on the Raspberry Pi side, and target detection was completed using a YOLOv8 model to output the pixel deviation of the target center; the deviation data were received by the STM32 via a serial interface, and an “obstacle-avoidance-first” motion-control strategy was implemented by fusing ultrasonic ranging, while a dual-axis pan–tilt mechanism was driven to coordinate laser pointing with vehicle motion. Experimental results showed that the system operated stably at a resolution of 640 × 480 and achieved real-time target tracking and pointing control. In multi-obstacle scenario tests, an obstacle-avoidance success rate of over 95% was obtained, and the laser pointing deviation was maintained within a small range. These results indicated that good real-time performance and stability were achieved, providing a reference for the engineering implementation of laser combat mobile platforms.
Laser Countermeasure; Intelligent Vehicle; YOLOv8; Target Tracking; Obstacle Avoidance Control; Gimbal Control.
Performance and Durability Evaluation of New Admixtures in Concrete Production
To address the drawbacks of high energy consumption and insufficient durability in traditional concrete, and to promote the greening and high-performance development of concrete, this study focuses on the application performance and durability of new industrial solid waste admixtures in concrete. Through single-factor variable experiments, the influence of different admixture dosages on the workability and mechanical properties of concrete was explored. Various testing methods were used to evaluate its impermeability, freeze-thaw resistance, chemical erosion resistance, and carbonation resistance, and the mechanism of action was analyzed using microscopic testing. The results show that, at appropriate dosages (15%–25%), the new admixtures can significantly optimize the workability and mechanical properties of concrete and improve durability indicators. A durability evaluation system based on multi-dimensional indicators was established, providing theoretical support and technical basis for the engineering application of the new admixtures.
Concrete; New Admixture; Application Performance; Durability; Experimental Evaluation.
A Single-phase Grounding Fault Location Method for Active Distribution Networks based on CPCA-CNN
Aiming at the problems of weak fault features and localization difficulties in active distribution networks, this paper proposes a fault location method that integrates Channel Prior Convolutional Attention (CPCA) and Convolutional Neural Networks (CNN). A Butterworth band-pass filter is utilized to preprocess zero-sequence currents, filtering out power frequency components and high-frequency noise. The one-dimensional transient signals are then transformed into high-dimensional time-frequency images through Transient Extraction Transform (TET). A CNN-based model is constructed to perform deep learning and feature extraction from these images. Generalization tests verify the effectiveness of the proposed method, achieving an overall accuracy of 99.98%.
Active Distribution Network; Fault Location; Transient Extraction Transform; Attention Mechanism.
Research on Standardized Maintenance Technology and Quality Control of Flameproof Motors and Electromagnetic Starters
Flameproof motors and electromagnetic starters are core electrical equipment in industrial production, especially in special operating scenarios such as underground coal mines. Their operational reliability is directly related to production efficiency and operational safety. Currently, equipment maintenance faces challenges including inconsistent technical standards, inadequate quality control systems, and insufficient intelligent monitoring methods, which are prone to inducing equipment failures and even safety accidents. Based on relevant national and industry standards, combined with advanced concepts such as lean management and intelligent monitoring, this paper systematically sorts out the standardized maintenance technical requirements for motors and electromagnetic starters, and constructs a full-process quality control system covering pre-maintenance, in-maintenance, and post-maintenance stages. By integrating technical means such as equipment full-life cycle management and intelligent monitoring and early warning, this study provides more comprehensive theoretical and practical support for improving equipment maintenance quality and ensuring stable equipment operation.
Flameproof Motor; Electromagnetic Starter; Standardized Maintenance; Quality Control; Lean Management; Explosion-proof Performance.
Global Path Planning for Unmanned Surface Vehicles based on Adaptive Parameter Q-Learning Algorithm
Global path planning is one of the core issues in the field of Unmanned Surface Vehicle (USV) navigation. As a classic method in reinforcement learning, the Q-Learning algorithm is widely applied to USV global path planning. However, the traditional Q-Learning algorithm typically employs a fixed learning rate, greedy rate, and discount factor, which leads to issues such as redundant exploration in the late training stage and slow convergence speed. To address these limitations, this paper proposes an adaptive parameter Q-Learning path planning algorithm. The proposed algorithm dynamically adjusts the greedy rate to balance exploration and exploitation, adaptively optimizes the learning rate based on the temporal difference (TD) error, and dynamically adjusts the discount factor by combining the distance between the current state and the destination. These improvements enhance both the convergence efficiency and path planning performance of the algorithm. Comparative experiments between the improved algorithm and the traditional Q-Learning algorithm were conducted in a simulated water environment. Experimental results demonstrate that the improved algorithm increases the training convergence speed by over 30% and shortens the optimal path length by 11%, indicating a significant improvement in algorithm performance. This study provides a more efficient algorithmic scheme for USV global path planning and holds great significance for enhancing the real-time performance, reliability, and environmental adaptability of USV navigation.
Unmanned Surface Vehicle (USV); Global Path Planning; Q-Learning Algorithm; Adaptive Parameters; Reinforcement Learning.
Building Surface Defect and Damage Detection Method based on YOLOv8-act
Detecting surface defects and damage on buildings is crucial for ensuring structural safety and durability. Traditional manual inspection methods are inefficient and highly subjective, making them inadequate for large-scale, high-precision engineering demands. This paper proposes a building surface defect detection method based on YOLOv8-act. By replacing the original SILU activation function with the SELU activation function-which possesses self-normalizing properties-the model's ability to extract features from low-contrast, irregularly shaped defects is enhanced. Experimental results demonstrate that the YOLOv8-act model achieves an mAP50 of 0.641, outperforming other compared models. This approach maintains real-time processing and deployment convenience while improving detection accuracy, providing an effective solution for automated and precise detection of building surface defects.
YOLOv8-act; Building Surface Defect Detection; Object Detection; Deep Learning; Computer Vision.
"Afflictions" and "Remedies" of Wooden Arch Lounge Bridges
Wooden arch lounge bridges in Zhejiang and Fujian provinces represent a unique heritage in the history of world bridge engineering. Their preservation faces ongoing challenges from both natural and anthropogenic factors. Focusing on the Shunde Bridge, part of the Chuzhou Lounge Bridges in Longquan City, Zhejiang Province-a national key cultural heritage protection unit-this paper addresses its structural safety crisis. Through comprehensive literature review, on-site investigation, and 3D laser scanning technology, a systematic survey and diagnosis of the bridge’s damages were conducted. The results reveal major deteriorations, including severe decay and insect infestation of key structural members of the wooden arch (e.g., three-joint seedlings), overall tilting and tenon dislocation of the lounge timber frame, and persistent leakage due to roofing system damage. Based on an analysis of the causes-natural aging, biological erosion, and limitations of prior interventions-and adhering to the principles of authenticity, integrity, and minimal intervention in cultural heritage conservation, this paper argues that partial repairs are insufficient to ensure the safety and value preservation of the heritage structure in its current state. Consequently, a systematic conservation and restoration design centered on "complete dismantling and major repair" is proposed. This study aims to provide a direct basis for eliminating fundamental safety risks to Shunde Bridge, while also offering a referential case for the holistic conservation practice of similar wooden heritage structures-from refined diagnosis to scientific intervention.
Wooden Arch Lounge Bridge; Shunde Bridge; Damage Investigation; 3D Laser Scanning; Complete Dismantling and Major Repair; Cultural Heritage Preservation.
Research Progress on the Recovery of Zinc from Steelmaking Dust by Calcination-Chlorination-Deep Eutectic Solvent Complexation Technology
Zinc, as a key raw material for the national economy, has seen a continuous increase in demand in China over the past two decades. In 2018, China's global consumption share exceeded 50%, making the recycling of zinc-containing waste an important way to ensure resource security. Steelmaking dust, a typical zinc-containing waste, had a zinc content of 400,000 to 1.5 million tons in China in 2018. However, traditional acid leaching consumes a large amount of acid and has complex iron removal processes, while ammonia leaching has a low leaching rate and high pollution risks, which have restricted the efficiency of zinc recovery. Low-melting eutectic solvents (DESs), with advantages such as being green and degradable and having an atomic utilization rate of 100%, offer a new direction for hydrometallurgical zinc extraction. The calcium-chlorination-DES composite technology breaks down the ZnFe2O4 spinel structure at low temperatures with a calcination agent, releasing easily soluble zinc compounds, which are then selectively leached by DES. The hydrogen bond complexation effect of DES enhances the solubility of zinc, achieving efficient separation of zinc and iron simultaneously. The zinc recovery rate reaches 85% to 95%, and the leaching time is reduced by 50%. This paper reviews the theoretical mechanism and research progress at home and abroad of this technology, analyzes the core challenges such as the optimization of calcination agents and the recycling and regeneration of DES, and proposes solutions such as the compounding of calcination agents and multi-stage recycling processes. Looking ahead, the optimization of compound calcination agents and the modification of DES molecules will be key research directions. This composite technology provides a green and efficient path for the resource utilization of zinc-containing waste and is of great significance for ensuring the strategic security of zinc resources in China.
Steelmaking Dust; Deep Eutectic Solvents; Calcination Chlorination; Composite Technology; Hydrometallurgical Zinc Extraction.
Study on Modification Methods for Supports of Methanol Steam Reforming Catalysts: Mini-Review
Load-type catalysts are widely used in heterogeneous catalytic reaction systems due to their high active component utilization, tunable structure, and ease of industrial scaling. Among these, methanol catalytic reforming for hydrogen production represents a significant hydrogen energy acquisition pathway. Methanol's abundant sources, convenient storage and transportation, and relatively high energy density make it highly promising for distributed hydrogen production. However, this reaction system features high Gibbs free energy and involves complex multistep processes including dehydrogenation, bond cleavage, and multivalent redox transformations. This complexity inevitably generates various carbon-containing chemical intermediates such as CO, formates, and methoxy groups. These intermediates not only occupy catalytic active sites and reduce reaction rates but may also lead to coking or metal sintering, causing catalyst deactivation and severely limiting overall reaction kinetics and stability. Therefore, there is an urgent need to develop supported catalysts with high activity, high selectivity, and long lifetime to achieve efficient hydrogen production with low byproduct formation. This paper focuses on supported catalysts, systematically reviewing current research progress in catalytic methanol reforming from two perspectives: support regulation and modification of supported active components. It emphasizes the influence of support acidity/basicity, defect/pore structure, metal dispersion, and interfacial interactions on catalytic performance. Finally, it summarizes and outlines future design strategies and development directions.
Supported Catalyst; Methanol Catalytic Reforming; Product Selectivity; Sintering; Carrier Modification.
Carbon Footprint Accounting Models and Methodologies for Industrialized Buildings
With the ongoing advancement of the "Dual Carbon" goals, the development model characterized by high carbon emissions in the traditional construction industry has become increasingly incompatible with the demands of green and low-carbon development. Industrialized construction, leveraging its advantages of standardization and intensification, has emerged as a critical pathway for carbon reduction. Carbon footprint accounting serves as a core mechanism for monitoring and managing carbon emissions throughout the entire life cycle of industrialized buildings. The scientific rigor of its accounting models and methodologies directly influences the effectiveness of carbon reduction efforts. This study concentrates on the essential issues of carbon footprint accounting for industrialized construction, conducting a systematic investigation into the construction rationale of accounting models and specific methodologies. It aims to provide data support and practical references for the formulation of comprehensive carbon reduction strategies and the practical implementation of low-carbon transformation in the industrialized building sector.
Industrialized Construction; Carbon Footprint; Accounting Model; Accounting Methodology.
Research on Trajectory Planning of a 6R Robotic Manipulator based on Jacobian Iteration
To meet the requirements of end-effector positioning accuracy and trajectory smoothness for laser positioning tasks of a 6R robotic manipulator, this paper investigates trajectory planning for a 6R robot based on a Jacobian iterative inverse kinematics method. First, a complete kinematic model of the 6R manipulator is established, and the mapping relationship between the end-effector pose and the joint variables is derived. On this basis, to address the limited applicability of analytical methods for manipulators with complex configurations, a Jacobian matrix–based iterative approach is introduced to solve the inverse kinematics problem, and an error-feedback mechanism is employed to achieve the gradual convergence of the end-effector pose to the desired target. Furthermore, considering the application scenario of laser positioning, straight-line trajectory planning of the end effector is performed in Cartesian space. Continuous linear motion trajectories are generated through linear interpolation between trajectory points. Simulation and experimental results demonstrate that the proposed Jacobian iterative method ensures convergence while effectively reducing the pose error between the robot end effector and the laser spot. The method also exhibits good stability and positioning accuracy within a certain range of motion.
Jacobian Iteration; Trajectory Planning; Laser Positioning; Kinematics.
Grey Relational Analysis of the Correlation between Various Crop Yields and Annual Precipitation in Henan Province Over the Last Decade
As a major agricultural province in China, the stable production of grain, oilseeds, and cash crops in Henan is critical to food security. In recent years, influenced by climate change, interannual precipitation fluctuations in the province have intensified, and the frequency of extreme drought and flood events has increased, exerting complex impacts on crop yields. Existing research predominantly focuses on individual crops, lacking comprehensive correlation analyses. Based on annual precipitation and major crop yield data from 2015 to 2024 in Henan Province, this study utilizes the Grey Relational Analysis (GRA) method to systematically quantify the correlation intensity between precipitation and 12 types of crops across three categories: grain, oilseed, and cash crops. Through data normalization, trend visualization, and relational grade calculation, the sensitivity differences of various crops to precipitation fluctuations were identified. This research provides theoretical and practical references for optimizing cropping structures, enhancing agricultural resilience, and ensuring food security.
Henan Province; Precipitation; Crop Yield; Grey Relational Analysis; Cropping Structure Optimization; Food Security.
Research on Hysteretic Model of Damaged H-Section Steel Columns
To address the insufficient consideration of residual deformation in traditional damage models for H-section steel columns, this study proposes a modified hysteretic model. Low-cycle cyclic loading tests were conducted on 5 Q355B H-section steel column specimens (HW150×150×7×10) to collect data on cumulative damage, residual deformation, and stiffness degradation. The classic Park-Ang model was modified by introducing residual deformation as a key parameter, and model parameters were calibrated using test data. Combined with trilinear skeleton curve fitting and adaptive hysteretic rules, a comprehensive hysteretic model was established. Verification results show that the model accurately predicts the hysteretic behavior and residual bearing capacity of damaged steel columns, with the error between simulated and test data within 8%. This research provides a reliable basis for seismic design and post-earthquake damage assessment of steel structures.
H-section Steel Columns; Residual Deformation; Park-Ang Model; Hysteretic Model; Low-cycle Cyclic Test.
Machine Vision-Based Laser-Powered Unmanned Aerial Vehicle System
To address the issues of short flight endurance and lengthy charging times for drones, a laser-powered drone system based on machine vision has been designed.This system centers on machine vision technology, integrating laser wireless power transmission. It employs the YOLOv11 object detection algorithm enhanced with an attention mechanism to improve detection accuracy for photovoltaic cells on drones, while utilizing PID control to optimize laser targeting precision.Experimental testing indicates that the system achieves over 95% confidence in detecting photovoltaic cell targets, with an inference time of 10.9 milliseconds per frame.This system features high recognition accuracy, rapid identification speed, and precise tracking, making it a portable and efficient laser-powered unmanned aerial vehicle system.
Machine Vision; Attention Mechanism; YOLOv11 Algorithm; PID Control.
Study on Sealing Performance of Packers for Supercritical CO2 Flooding
During the process of supercritical CO2 injection, the corrosion of rubber materials frequently leads to the sealing failure of packer elements. To address this issue, this study employs Hydrogenated Nitrile Butadiene Rubber (HNBR) sealing elements and conducts finite element simulations based on the Yeoh hyperelastic constitutive model. The impact on sealing performance is analyzed from four dimensions: the phase state of the corrosive medium, temperature, acid gas composition, and corrosion duration. The simulation results indicate that: Phase state and temperature primarily compromise structural integrity: Under conditions involving formation water or high temperatures (160°C), physical swelling and constrained thermal expansion induce severe stress concentrations at the element's shoulder (with increases of 80.47% and 165.81%, respectively). This phenomenon significantly increases susceptibility to bulk rupture or extrusion failure. H₂S content and service duration primarily govern the decay of contact pressure: Chemical attack by H₂S and prolonged service (8 days) lead to modulus degradation and stress relaxation. These factors result in a substantial decline in contact sealing stress (reductions of 28.26% and 62.92%, respectively), thereby significantly elevating the risk of interfacial leakage.Based on finite element analysis, this study elucidates the impact of various corrosion factors on sealing performance, providing a theoretical basis for the long-term safety evaluation of packers in supercritical CO2 injection applications.
Packer Element; Supercritical CO2; Sealing Performance; Corrosion; Finite Element Analysis.
Numerical Analysis of the Stability of Excavation Support and its Impact on Factory Foundation
This paper establishes a three-dimensional detailed numerical model of foundation pit excavation using the finite element simulation software Midas GTS NX to analyze the deformation characteristics of the excavation support structure, factory cap foundation, and pile foundations under three working conditions. The study shows that during the excavation process, due to lateral soil movement, the maximum horizontal displacement of the excavation support piles is concentrated in the middle and lower parts, while the vertical displacement is influenced by the reinforcing effect of the pile foundations. The support piles closer to the piles exhibit smaller vertical displacement, while those farther from the piles exhibit larger displacement. The horizontal and vertical displacements of the cap beams and steel pipe supports show relatively symmetric distribution. In the case of pile foundations and cap foundations, the impact of the excavation on horizontal and vertical displacements is small, with the largest displacement concentrated in the upper part of the pile foundations and the middle inner part of the cap foundations. In conclusion, the impact of foundation pit excavation is minimal on the displacement of pile foundations and cap foundations due to the shallow excavation depth and good overall stability of the excavation support structure. However, the numerical simulation only considers ideal conditions, and variations during construction are not fully reflected. Therefore, construction quality must be strictly controlled during the project, especially regarding the construction quality of cement-soil mixing piles, to ensure the smooth progress of the project.
Foundation Pit Excavation; Finite Element Numerical Simulation; Midas GTS NX; Excavation Support Structure; Pile Foundation; Cap Foundation; Construction Quality.