期刊：
International Journal of Heat and Fluid Flow,2026年117:110035 ISSN：0142-727X
通讯作者：
Yanfeng Yang
作者机构：
[Chaolin Liu; Chaofan Xiao] School of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114, China;[Sanqi Liu] Chengnan College, Changsha University of Science and Technology, Changsha 410015, China;Hebei Key Laboratory of Physics and Energy Technology, Baoding 071003, China;[Yanfeng Yang] School of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Hebei Key Laboratory of Physics and Energy Technology, Baoding 071003, China
通讯机构：
[Yanfeng Yang] S;School of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Hebei Key Laboratory of Physics and Energy Technology, Baoding 071003, China
摘要：
In this study, a two-dimensional cylindrical tube array model was established using the finite element method. The effects of sound wave frequency (50–200 Hz) and sound pressure level (118–140 dB) on the flow characteristics in the inter-tube gap under laminar ( Re = 150) and turbulent ( Re = 500) conditions were systematically investigated. The results show that under laminar conditions, the average gap flow velocity increases from 0.025 m/s to 0.048 m/s when the sound pressure level rises from 118 dB to 130 dB at a 50 Hz sound wave, representing a 177 % increase. However, at a constant sound pressure level of 130 dB, the flow velocity of the front row tubes (C1-C7) significantly decreases as the frequency increases from 50 Hz to 200 Hz. Under turbulent conditions, the flow velocity increases linearly by 33 % within the range of 130–140 dB at 50 Hz sound waves. Even though the flow velocity decreases when the frequency increases to 140 dB sound pressure, it is still higher than that without sound waves. The study found that low-frequency sound waves have a more significant effect on enhancing the flow of the front row tubes, while high-frequency sound waves need to consider energy dissipation. Overall, low-frequency and high sound pressure level sound waves can effectively increase the inter-tube flow velocity, and the enhancement effect is more obvious under laminar conditions. This provides a theoretical basis for the optimization of sound wave parameters in engineering applications.
In this study, a two-dimensional cylindrical tube array model was established using the finite element method. The effects of sound wave frequency (50–200 Hz) and sound pressure level (118–140 dB) on the flow characteristics in the inter-tube gap under laminar ( Re = 150) and turbulent ( Re = 500) conditions were systematically investigated. The results show that under laminar conditions, the average gap flow velocity increases from 0.025 m/s to 0.048 m/s when the sound pressure level rises from 118 dB to 130 dB at a 50 Hz sound wave, representing a 177 % increase. However, at a constant sound pressure level of 130 dB, the flow velocity of the front row tubes (C1-C7) significantly decreases as the frequency increases from 50 Hz to 200 Hz. Under turbulent conditions, the flow velocity increases linearly by 33 % within the range of 130–140 dB at 50 Hz sound waves. Even though the flow velocity decreases when the frequency increases to 140 dB sound pressure, it is still higher than that without sound waves. The study found that low-frequency sound waves have a more significant effect on enhancing the flow of the front row tubes, while high-frequency sound waves need to consider energy dissipation. Overall, low-frequency and high sound pressure level sound waves can effectively increase the inter-tube flow velocity, and the enhancement effect is more obvious under laminar conditions. This provides a theoretical basis for the optimization of sound wave parameters in engineering applications.
关键词：
Internet of Vehicles;blockchain;federated learning;cybersecurity;distributed systems
摘要：
The Internet of Vehicles (IoV) operates in an environment characterized by asymmetric security threats, where centralized vulnerabilities create a critical imbalance that can be disproportionately exploited by attackers. This study addresses this imbalance by proposing a symmetrical security framework that integrates Blockchain and Federated Learning (FL) to restore equilibrium in the Vehicle-Road-Cloud ecosystem. The evolution toward sixth-generation (6G) technologies amplifies both the potential of vehicle-to-everything (V2X) communications and its inherent security risks. The proposed framework achieves a delicate balance between robust security and operational efficiency. By leveraging blockchain's symmetrical and decentralized distribution of trust, the framework ensures data and model integrity. Concurrently, the privacy-preserving approach of FL balances the need for collaborative intelligence with the imperative of safeguarding sensitive vehicle data. A novel Cloud Proxy Re-Encryption Offloading (CPRE-IoV) algorithm is introduced to facilitate efficient model updates. The architecture employs a partitioned blockchain and a smart contract-driven FL pipeline to symmetrically neutralize threats from malicious nodes. Finally, extensive simulations validate the framework's effectiveness in establishing a resilient and symmetrically secure foundation for next-generation IoV networks.
摘要：
The high-rate operation of lithium-ion batteries induces rapid heat accumulation, posing critical challenges for thermal safety and longevity. This study presents a hybrid thermal management system integrating phase change material (PCM) with liquid cooling under high-rate operation. Key parameters including coolant flow rate, temperature, channel geometry, and PCM configuration are systematically optimized at a 5C discharge rate. An S-shaped channel with a 2mm × 4 mm cross-section is optimized, achieving a peak temperature of 47.5 °C (below the 50 °C safety threshold) and a PCM liquid fraction of 0.4, while maintaining a maximum temperature difference of 5.5 °C. Enhanced convective cooling at 0.06 m/s flow velocity can balance the cooling efficiency and energy consumption. The length of cross-sectional optimization (4 mm cross-section, triple-bend structure) can minimise thermal gradients. Multi-cell PCM encapsulation strategies improve temperature performance ensuring thermal safety. These results demonstrate that the novel hybrid thermal management system can effectively enhance temperature uniformity. It offers a scalable solution for high-power battery systems in electric vehicles and energy storage applications.
The high-rate operation of lithium-ion batteries induces rapid heat accumulation, posing critical challenges for thermal safety and longevity. This study presents a hybrid thermal management system integrating phase change material (PCM) with liquid cooling under high-rate operation. Key parameters including coolant flow rate, temperature, channel geometry, and PCM configuration are systematically optimized at a 5C discharge rate. An S-shaped channel with a 2mm × 4 mm cross-section is optimized, achieving a peak temperature of 47.5 °C (below the 50 °C safety threshold) and a PCM liquid fraction of 0.4, while maintaining a maximum temperature difference of 5.5 °C. Enhanced convective cooling at 0.06 m/s flow velocity can balance the cooling efficiency and energy consumption. The length of cross-sectional optimization (4 mm cross-section, triple-bend structure) can minimise thermal gradients. Multi-cell PCM encapsulation strategies improve temperature performance ensuring thermal safety. These results demonstrate that the novel hybrid thermal management system can effectively enhance temperature uniformity. It offers a scalable solution for high-power battery systems in electric vehicles and energy storage applications.
关键词：
First principles;LiFePO4;Doping;Lithium-ion battery;Electrochemical properties
摘要：
In order to improve the electrochemical performance of LiFePO 4 (LFP) electrode, Cu and Mg co-doped LFP cathode materials were synthesized via a high-temperature solid-state reaction method. The phase purity and morphology were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). Based on co-doped cathode material, the coin-type cells was assembled for galvanostatic charge-discharge testing. The combined synergistic effect of co-doping into LFP were investigated through density functional theory(DFT) calculations. The first-principles calculation method was employed to study the thermodynamic stability, electronic structure properties, intercalation voltage, and lithium-ion diffusion characteristics of Cu and Mg-doped LiFePO 4 . The results show that smaller particle sizes and larger specific surface areas for Cu and Mg co-doping. It facilitates the diffusion of LFP on the surface and within the bulk of the cathode material during charge and discharge processes. This leads to reduce polarization and thus improve electrochemical performance. A higher initial discharge specific capacity of 142.4 mAh/g is exhibited compared to the undoped counterpart. The incorporation of Cu and Mg reduces the band gap from 3.66 eV to 0.4 eV. This suggests that the electrical conductivity is improved due to electrons more easily transition from the valence band to the conduction band. After co-doping, the lithium ion diffusion barrier decreases from 1.08 eV to 0.75 eV. It is predicted that lithium ions diffuse in LFP-CM six orders of magnitude faster than in its intrinsic counterpart. Meanwhile, a platform with a high operating voltage of 3.64 V makes a positive contribution to the electrochemical performance.
In order to improve the electrochemical performance of LiFePO 4 (LFP) electrode, Cu and Mg co-doped LFP cathode materials were synthesized via a high-temperature solid-state reaction method. The phase purity and morphology were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). Based on co-doped cathode material, the coin-type cells was assembled for galvanostatic charge-discharge testing. The combined synergistic effect of co-doping into LFP were investigated through density functional theory(DFT) calculations. The first-principles calculation method was employed to study the thermodynamic stability, electronic structure properties, intercalation voltage, and lithium-ion diffusion characteristics of Cu and Mg-doped LiFePO 4 . The results show that smaller particle sizes and larger specific surface areas for Cu and Mg co-doping. It facilitates the diffusion of LFP on the surface and within the bulk of the cathode material during charge and discharge processes. This leads to reduce polarization and thus improve electrochemical performance. A higher initial discharge specific capacity of 142.4 mAh/g is exhibited compared to the undoped counterpart. The incorporation of Cu and Mg reduces the band gap from 3.66 eV to 0.4 eV. This suggests that the electrical conductivity is improved due to electrons more easily transition from the valence band to the conduction band. After co-doping, the lithium ion diffusion barrier decreases from 1.08 eV to 0.75 eV. It is predicted that lithium ions diffuse in LFP-CM six orders of magnitude faster than in its intrinsic counterpart. Meanwhile, a platform with a high operating voltage of 3.64 V makes a positive contribution to the electrochemical performance.
作者机构：
[Liu, Yaru; Xiong, Lingyun; Liu, YR] Changsha Univ Sci & Technol, Natl Key Lab Green & Long Life Rd Engn Extreme Env, Changsha 410114, Hunan, Peoples R China.;[Liu, Yaru; Liu, YR] Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Peoples R China.;[Xiong, Lingyun] Changsha Univ Sci & Technol, Chengnan Coll, Changsha 410076, Peoples R China.;[Zeng, Qing] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Peoples R China.;[Lai, Jianping] Southwest Univ Sci & Technol, Key Lab Testing Technol Mfg Proc, State Key Lab Environm friendly Energy Mat, State Key Lab Environm Friendly Energy Mat, Mianyang 621010, Peoples R China.
通讯机构：
[Liu, YR ] C;Changsha Univ Sci & Technol, Natl Key Lab Green & Long Life Rd Engn Extreme Env, Changsha 410114, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Peoples R China.
摘要：
The present work investigated the effect of destabilization time on the mechanical properties and microstructure evolution of high chromium cast iron, and scanning electron microscopy and electron probe microanalysis techniques were employed. The results show that the hardness of hypoeutectic high chromium cast iron is related to the size and volume fraction of secondary carbides precipitated from the matrix. The hardness of the alloy continues to rise due to the continuous increase of the volume fraction of the secondary carbide at the initial stage of destabilization. The alloy reaches its peak hardness value at 950 degrees C and 1000 degrees C for 1 hour holding time. The solid solubility of carbon and alloying elements in the matrix increases as the holding time extends, resulting in a large number of carbides redissolved into the matrix, making the hardness of the alloy decrease; the hardness of the alloy at 14 h is less than that at 10 min. Under 1050 degrees C, the size and density of the secondary carbide increase significantly; extending the holding time will lead to the continuous reduction of the carbide rod that provides strength, thus, the hardness curve shows a downward trend. The present work investigated the effect of destabilization time on the mechanical properties and microstructure evolution of high chromium cast iron, and scanning electron microscopy and electron probe microanalysis techniques were employed.
摘要：
Desiccation cracking is a major cause of shallow failure of lateritic soil slopes. Knowledge of soil tensile strength helps better understand the cracking behavior of vegetated lateritic soil. This study aims to examine the surficial cracking behavior and tensile strength of remolded lateritic soil containing horizontally arranged vetiver roots. Desiccation cracking tests, root pullout tests and direct tensile tests were performed on lateritic soil considering various porosities, degrees of saturation, and root contents. The mechanism underlying the root reinforcement was analyzed by scanning electron microscopy. The results demonstrate that adding 0.4% grass roots can reduce the crack width and crack intensity factor, and thus mitigate crack developments in lateritic soil. The interfacial shear strength exhibits a decreasing trend with increasing root diameter. As the root content increases from 0% to 1.0%, the tensile strength of lateritic soil increases to reach the peak at a root content of 0.4%-0.5% and then drops greatly. This is why the optimal root content in resisting crack development is about 0.4%. Microscopic tests show that the interfacial shear strength originates from the friction, interlocking force, cementation and capillary force between the rough root surface and surrounding soil particles. A power function-based empirical equation expressed by the root diameter and porosity is proposed to estimate the interfacial shear strength of rooted lateritic soil. Additionally, a semi-theoretical equation of the tensile strength of rooted lateritic soil is deduced based on the tensile strength of soil matrix and the interfacial shear strength between the roots and soil matrix. This equation considers the root content and root diameter distribution and is applicable to the soil of different state parameters (e.g., porosity, degree of saturation and water content). The results could provide insights into the mitigation of desiccation cracking in lateritic soil slopes with root-reinforcement technology.
通讯机构：
[Fudong Li] S;School of Mechanical and Electrical Engineering, Beijing Information Science and Technology University, Beijing 100192, China<&wdkj&>Author to whom correspondence should be addressed.
期刊：
Proceedings of the Institution of Civil Engineers: Engineering and Computational Mechanics,2023年176(2):65-83 ISSN：1755-0777
作者机构：
[Xiaofang Kang; Yi Cai] Professor, Anhui Institute of Intelligent Underground Detection Technology, School of Civil Engineering, Anhui Jianzhu University, Hefei, China;[Shuai Li] Post-graduate, School of Civil Engineering, Anhui Jianzhu University, Hefei, China;[Jun Hu] Professor, School of Civil Engineering, Anhui Jianzhu University, Hefei, China;Professor, chool of Civil Engineering, Anhui Jianzhu University, Hefei, China (corresponding author: xgh@ahjzu.edu.cn );[Jun Zheng; Jiaxin Luo; Guoliang Liu; Xinqi Wang; Qiwen Huang] Undergraduate, School of Civil Engineering, Anhui Jianzhu University, Hefei, China
摘要：
In this paper, two adjacent buildings of unequal height are established using finite-element software, and damping devices are connected between the two buildings. The results of three models were obtained through non-linear analysis. These include the adjacent building model (CAIM-T) based on the tuned viscous mass damper, the adjacent building model (CAIM-V) with the viscous damper connection (CAIM-V) and adjacent building structure no additional damping model (CAIM). The results show that through reasonable parameter design and adjustment, compared with the CAIM system, the CAIM-T system and the CAIM-V system can weaken the interlayer drift and floor acceleration of the building structure, and the CAIM-T system has better vibration control effect than the CAIM-V system.
In this paper, two adjacent buildings of unequal height are established using finite-element software, and damping devices are connected between the two buildings. The results of three models were obtained through non-linear analysis. These include the adjacent building model (CAIM-T) based on the tuned viscous mass damper, the adjacent building model (CAIM-V) with the viscous damper connection (CAIM-V) and adjacent building structure no additional damping model (CAIM). The results show that through reasonable parameter design and adjustment, compared with the CAIM system, the CAIM-T system and the CAIM-V system can weaken the interlayer drift and floor acceleration of the building structure, and the CAIM-T system has better vibration control effect than the CAIM-V system.
关键词：
Mesostructure;High temperature performance;Low temperature performance;Digital image processing;Correlation analysis
摘要：
The distribution characteristics of the mesostructure of asphalt mixtures have an important influence on the macroscopic performance of asphalt mixtures. In this study, by means of industrial computed tomography and voxel analysis, the distribution of voids and skeleton microstructure of asphalt mixture is characterized from multiple perspectives. The relationship between mesostructural characteristic parameters and macroscopic properties of asphalt mixtures was established by the indirect tensile test, uniaxial compression test, and digital image correlation test. The results show that the mesostructural distribution of the voids of different types of asphalt mixtures shows a certain degree of transverse isotropy. Air voids content and fractal dimension of voids are the mesostructural characteristic parameters that affect the cracking resistance of asphalt mixtures at low temperatures. The air voids content has a negative exponential relationship with the strength of asphalt mixture. When the void fractal dimension is 1.3, the splitting tensile strength of asphalt mixture reaches the maximum value. Skeleton structure is a mesostructure characteristic parameter that affects the high temperature stability of asphalt mixture. The lower voids in coarse aggregate skeletons and degree of anisotropy are positively correlated with the uniaxial compressive strength. After voids in coarse aggregate skeletons are lower than 35 %, the uniaxial compressive strength of asphalt mixture is significantly improved. The proposed skeleton evaluation index can effectively characterize the material composition differences of different types of asphalt mixtures. The strain cloud diagram of the digital correlation experiment shows the place where the void distribution first reached the maximum strain of about 0.003 during loading, and the high strain area corresponds to the void centroid distribution. The air voids centroid distribution is the mesostructural characteristic parameter of the indirect tensile strain distribution.
