摘要：
Internal damage imaging in concrete structures has consistently presented significant challenges as a complex multi-component material. To enhance the accuracy and efficiency of internal damage identification in concrete structures, an improved plane wave imaging technique based on the wavenumber algorithm is proposed in the paper. The introduction of the wavenumber algorithm provides a mathematical solution to the inverse problem for the assumed forward wave propagation model, which is more rigorous than the ray-based theory in mathematics. By comparing with the total focusing method and the conventional plane wave imaging technique, the proposed imaging technique exhibits significant advantages in imaging different types of damage in concrete structures. Subsequently, the 3D damage state of the simulated reinforcement steel debonding in concrete structures was reconstructed employing the proposed imaging technique. The enhanced imaging efficiency and optimized imaging quality settled the proposed imaging technique a promising candidate for future internal damage identification of concrete structures.
Internal damage imaging in concrete structures has consistently presented significant challenges as a complex multi-component material. To enhance the accuracy and efficiency of internal damage identification in concrete structures, an improved plane wave imaging technique based on the wavenumber algorithm is proposed in the paper. The introduction of the wavenumber algorithm provides a mathematical solution to the inverse problem for the assumed forward wave propagation model, which is more rigorous than the ray-based theory in mathematics. By comparing with the total focusing method and the conventional plane wave imaging technique, the proposed imaging technique exhibits significant advantages in imaging different types of damage in concrete structures. Subsequently, the 3D damage state of the simulated reinforcement steel debonding in concrete structures was reconstructed employing the proposed imaging technique. The enhanced imaging efficiency and optimized imaging quality settled the proposed imaging technique a promising candidate for future internal damage identification of concrete structures.
摘要：
This paper focuses on the existence of normalized solutions for the Chern–Simons–Schrödinger system with mixed dispersion and critical exponential growth. These solutions correspond to critical points of the underlying energy functional under the L 2 $$ {L}^2 $$ -norm constraint, namely, ∫ ℝ 2 u 2 d x = c > 0 $$ {\int}_{{\mathrm{\mathbb{R}}}^2}{u}^2\mathrm{d}x=c>0 $$ . Under certain mild assumptions, we establish the existence of nontrivial solutions by developing new mathematical strategies and analytical techniques for the given system. These results extend and improve the results in the existing literature.
关键词：
Corporate financialization;Environmental investment;Internal control quality;Managerial myopia;Preference
摘要：
Corporate executives often favor short-term "end-of-pipe" solutions to comply with environmental regulations. In this study, we examine how managerial myopia influences corporate preferences for environmental investments, using data from listed Chinese firms between 2007 and 2021. Grounded in the upper-echelon and time orientation theories, this analysis reveals that managerial myopia discourages environmental investments, with a more pronounced impact on preventive measures compared to treatment-focused approaches. Mechanism tests indicate that managerial myopia impacts environmental investments by increasing financialization and reducing the quality of internal controls. Heterogeneity analysis further reveals specific contexts where managerial myopia is particularly inhibitory. Notably, preventative environmental investments can yield "innovation compensation" that ultimately improves financial performance. These findings may provide valuable insights for investors, analysts, board directors, and regulators seeking to understand and shape corporate strategies for environmental management.
摘要：
The solid propellant is a particle-reinforced material with significant tension-compression asymmetry. Based on the constant-speed tensile test, constant-speed compression test, and cross-sectional SEM scanning test, this study investigated the differences in the mechanical properties of the HTPB propellant under tensile and compressive loading and the underlying mechanisms. The results show that the tensile strength of HTPB propellant is much smaller than compressive strength. According to the SEM test results of the failure surface, the tensile mechanical properties of the propellant are mainly affected by matrix, and the influence of particles on the mechanical properties is more obvious during the compression process. According to test data, a tension-compression integrated nonlinear constitutive model was constructed, and its application in simulation calculation was realized. The results show that the theoretical, simulation calculation and test results are in good agreement. At 15% strain, the maximum error between the theoretical results and the experimental curve is 9.1% and 4.8% respectively in the process of tension and compression. Therefore, the model can accurately describe the stress-strain relationship of HTPB propellant under different strain rates of tensile and compression. This model can provide theoretical support for accurately evaluating the structural integrity of SRMs.
关键词：
Circulating fluidized bed fly ash;Ground granulated blast-furnace slag;Grout materials;Geopolymers;Performance;Microstructure
摘要：
Circulating fluidized bed fly ash (CFBFA) is a significant byproduct of power plants and has attracted considerable attention due to its potential as a low-cost geopolymer precursor. However, unstable components in CFBFA, such as sulfur trioxide (SO 3 ) and free lime (f-CaO), can lead to volumetric expansion, which limits its widespread application in cementitious materials. To address this issue, this study effectively combines CFBFA with ground granulated blast furnace slag (GGBS) to develop an environmentally friendly micro-expansive geopolymer subgrade grouting material. This approach enhances the utilization of CFBFA in cementitious applications. The research demonstrates that the utilization rate of CFBFA in the geopolymer grouting material can reach 70 %, and the material meets the subgrade grouting specifications for fluidity, setting time, and compressive strength. The developed grout material exhibits micro-expansive behavior that significantly improves repaired subgrade performance. Furthermore, freeze-thaw cycle test results confirm the durability of the grouting material, indicating that micro-expansion has a negligible effect on its durability. Additionally, X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP) analyses were conducted to investigate the composition and microstructure of the grouting material with varying CFBFA dosages. These analyses reveal the performance evolution mechanisms of the grouting material, providing valuable insights into its preparation. Based on the experimental results, it is recommended to use a CFBFA content of 65–70 %, a GGBS content of 30–35 %, a 1.0 M alkaline activator at 35 % dosage, and a water-to-solid ratio of 0.65 to prepare high-performance subgrade grouting materials with micro-expansive properties and excellent durability. Therefore, this paper introduces a novel method for producing geopolymer subgrade grouting materials using CFBFA and GGBS, offering a new perspective on the wide application of CFBFA in cementitious materials and contributing to the reduction of its environmental impact.
Circulating fluidized bed fly ash (CFBFA) is a significant byproduct of power plants and has attracted considerable attention due to its potential as a low-cost geopolymer precursor. However, unstable components in CFBFA, such as sulfur trioxide (SO 3 ) and free lime (f-CaO), can lead to volumetric expansion, which limits its widespread application in cementitious materials. To address this issue, this study effectively combines CFBFA with ground granulated blast furnace slag (GGBS) to develop an environmentally friendly micro-expansive geopolymer subgrade grouting material. This approach enhances the utilization of CFBFA in cementitious applications. The research demonstrates that the utilization rate of CFBFA in the geopolymer grouting material can reach 70 %, and the material meets the subgrade grouting specifications for fluidity, setting time, and compressive strength. The developed grout material exhibits micro-expansive behavior that significantly improves repaired subgrade performance. Furthermore, freeze-thaw cycle test results confirm the durability of the grouting material, indicating that micro-expansion has a negligible effect on its durability. Additionally, X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP) analyses were conducted to investigate the composition and microstructure of the grouting material with varying CFBFA dosages. These analyses reveal the performance evolution mechanisms of the grouting material, providing valuable insights into its preparation. Based on the experimental results, it is recommended to use a CFBFA content of 65–70 %, a GGBS content of 30–35 %, a 1.0 M alkaline activator at 35 % dosage, and a water-to-solid ratio of 0.65 to prepare high-performance subgrade grouting materials with micro-expansive properties and excellent durability. Therefore, this paper introduces a novel method for producing geopolymer subgrade grouting materials using CFBFA and GGBS, offering a new perspective on the wide application of CFBFA in cementitious materials and contributing to the reduction of its environmental impact.
摘要：
Thin-layer covers easily crack under traffic load, shortening their service life. Incorporating fiber materials into the mix can enhance crack resistance thanks to their abundance, affordability, and flexibility. However, different types of fibers have different performances in bitumen and mixtures due to different material properties. To explore this problem, basalt fiber, polypropylene fiber, and glass fiber were selected in this paper. The surface characteristics, internal structure, and adsorption capacity of oily substances were observed via scanning electron microscopy and oil absorption rate testing. The effects of fibers on the high-temperature and low-temperature properties of styrene-butadiene-styrene block copolymer-modified bitumen were investigated using the dynamic shear rheometer and the force ductility method. Ultimately, through indirect tensile testing and semi-circular bending tests, and the introduction of the toughness index and fracture toughness, a comprehensive evaluation was conducted on how varying fiber types and content affect the crack resistance and toughness of bitumen mixtures. The results show that the density and dispersion of the bundle fibers are the key to the oil absorption capacity under similar internal and external structural conditions. The oil absorption rate of polypropylene fiber is the best, reaching 5.423. Fiber incorporation can significantly improve the high-temperature rheological properties of bitumen. At 4% dosage, G*/sinδ increased by about 107.04% on average at 76 °C. At low temperatures, the increase in fiber content leads to a decrease in bitumen elasticity, and the influence of glass fiber is more obvious. The area of toughness did not reach 2000 N·mm at 4% dosage. After adding fibers, the toughness index and fracture toughness of the mixture increased by more than 2% and 35%, respectively. The maximum increases in fracture energy and crack initiation energy of the mixture are 14.29% and 47.29%, respectively. It shows that the fiber enhances the toughness, crack resistance, and crack propagation resistance of the mixture. The research results can provide some reference for the application of fiber-reinforced bitumen mixtures.
摘要：
In order to investigate the influence of the coexistence of clay and silt on the compression characteristics of sand, one-dimensional compression consolidation tests were carried out on reconstituted saturated sand-silt-clay mixtures with a constant initial void ratio, and the effects of fines content (FC) and clay-silt ratio (CS) on the compression characteristics of mixed soils were studied. The mechanism of the experimental results was additionally explained from a microscopic perspective. The test results show that: the compressibility of mixed soil increased with the increase in FC; the compressibility change rule of mixed soils with different CS is consistent under the same FC; the influence of CS on the e-lgp (the void ratio (e) versus logarithm of the pressure (p)) curve of mixed soil is inconsistent when FC is different: when FC = 3%, the compressibility of mixed soil decreased with the increase in CS; when FC = 7% and 10%, the compressibility of mixed soil gradually increased with the increase in CS; when FC = 5%, the compressibility of mixed soil did not show an obvious changing law with the increase in CS, and the compressibility of the specimen with FC = 5%-CS = 1 (FC = 5%, CS = 1) was the largest; when CS was same, the difference between e-lgp curves of mixed soil with different FC increased with the increase in CS. The compression model of sand-silt-clay mixtures was established, which can consider the effects of FC and CS. The reliability and applicability of the proposed model were verified by combining the experimental results of this paper and the test data of sand-clay mixture and sand-silt mixture in other literature.
作者机构：
[Song, Jun; Wang, Xiangjun; Li, Chunguang] School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, China;Elite Engineering School, Changsha University of Science & Technology, Changsha 410114, China;State Key Laboratory of Disaster Prevention & Reduction for Power Grid, Changsha University of Science & Technology, Changsha 410114, China;[Li, Kai] School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Elite Engineering School, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>State Key Laboratory of Disaster Prevention & Reduction for Power Grid, Changsha University of Science & Technology, Changsha 410114, China;[Han, Yan] School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Elite Engineering School, Changsha University of Science & Technology, Changsha 410114, China
通讯机构：
[Kai Li] S;School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Elite Engineering School, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>State Key Laboratory of Disaster Prevention & Reduction for Power Grid, Changsha University of Science & Technology, Changsha 410114, China
摘要：
Nonlinear flutter has attracted wide attention due to the bottleneck caused by linear flutter theory on flutter-resistant design of super-long-span bridges. The longer the span, the more closely spaced the natural modes, which may cause competition among flutter-modes in a nonlinear flutter, but it is rarely reported so far. To this end, this study experimentally investigates the 3D nonlinear flutter characteristics of a long-span suspension bridge with closely spaced natural modes based on full-bridge aeroelastic model wind tunnel tests. Since there are two unstable flutter-modes within the interested post-critical regime and thus various complex but interesting flutter-modes competition processes were observed, such as continuous modes competition where the vibration amplitude evolution exhibits various different types of “sawtooth” shapes during stable vibration stages. Meanwhile, the complex nonlinear bifurcation behaviors caused by modes competition were also observed. The evolutionary characteristics of flutter-modes competition are analyzed in detail and relevant mechanisms are discussed. As the wind speed increases, the flutter of the studied bridge mainly undergoes a transition from being dominated by the symmetric mode to being dominated by the antisymmetric mode, accompanied by a continuous modes competition zone in between as a transitional zone. The results show that the continuous modes competition will result in a decrease in the maximum amplitude RMS of the full-span, which is beneficial for the structure. But it may also lead to a transient increase in the maximum amplitude of the full-span due to the coupling vibration shape formed by the two significant flutter-modes, which may be bad for the structure.
Nonlinear flutter has attracted wide attention due to the bottleneck caused by linear flutter theory on flutter-resistant design of super-long-span bridges. The longer the span, the more closely spaced the natural modes, which may cause competition among flutter-modes in a nonlinear flutter, but it is rarely reported so far. To this end, this study experimentally investigates the 3D nonlinear flutter characteristics of a long-span suspension bridge with closely spaced natural modes based on full-bridge aeroelastic model wind tunnel tests. Since there are two unstable flutter-modes within the interested post-critical regime and thus various complex but interesting flutter-modes competition processes were observed, such as continuous modes competition where the vibration amplitude evolution exhibits various different types of “sawtooth” shapes during stable vibration stages. Meanwhile, the complex nonlinear bifurcation behaviors caused by modes competition were also observed. The evolutionary characteristics of flutter-modes competition are analyzed in detail and relevant mechanisms are discussed. As the wind speed increases, the flutter of the studied bridge mainly undergoes a transition from being dominated by the symmetric mode to being dominated by the antisymmetric mode, accompanied by a continuous modes competition zone in between as a transitional zone. The results show that the continuous modes competition will result in a decrease in the maximum amplitude RMS of the full-span, which is beneficial for the structure. But it may also lead to a transient increase in the maximum amplitude of the full-span due to the coupling vibration shape formed by the two significant flutter-modes, which may be bad for the structure.
期刊：
Electric Power Systems Research,2025年238:111132 ISSN：0378-7796
通讯作者：
Yu Peng<&wdkj&>Sheng Su
作者机构：
[Chengcheng Yi; Yu Peng; Sheng Su; Bin Li; Xiaoqian Wang; Wenqing Zhou; Hongming Yang] The College of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha, Hunan 410114, China;[Xin Guo] The School of Intelligent Manufacturing, Hunan First Normal University, Changsha, Hunan 410205, China;[Wenchuan Meng] Energy Development Research Institute, China Southern Power Grid, Guangzhou, 510663, China
通讯机构：
[Yu Peng; Sheng Su] T;The College of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha, Hunan 410114, China
关键词：
Photovoltaic power generation;Power outlier detection;Sunny day screening;Quantile regression recurrent neural network;Power output correlation
摘要：
Distributed photovoltaic (PV) power generation systems are widely spread. Moreover, due to the randomness of meteorological conditions and the complexity of installation environments, it is difficult to eliminate the interference of factors such as meteorological fluctuations in the monitoring of abnormal states of PV equipment. Based on this, this paper proposes a PV power generation anomaly detection method based on Quantile Regression Recurrent Neural Network (QRRNN). First, the characteristics of solar irradiance on clear days are analyzed, and the clear day masking method is used to eliminate the interference of cloudy and rainy weather. Then, the output correlation of different power stations is analyzed to obtain PV stations with high output correlation as the horizontal reference, which is used to exclude interferences such as permanent faults at the power stations. At the same time, vertical comparison of the output curves of the station under test on different clear days is conducted to eliminate interference factors such as weather and environmental conditions. Subsequently, the metered active power output data, which is free from interference, is input into the QRRNN model to obtain the normal active power output range of the PV. The power threshold of the normal output range is utilized to identify anomalies in PV power generation. Finally, simulation analysis of actual PV system data is conducted, and the results show that the method can effectively identify PV power generation anomalies and has high accuracy in PV fault detection.
Distributed photovoltaic (PV) power generation systems are widely spread. Moreover, due to the randomness of meteorological conditions and the complexity of installation environments, it is difficult to eliminate the interference of factors such as meteorological fluctuations in the monitoring of abnormal states of PV equipment. Based on this, this paper proposes a PV power generation anomaly detection method based on Quantile Regression Recurrent Neural Network (QRRNN). First, the characteristics of solar irradiance on clear days are analyzed, and the clear day masking method is used to eliminate the interference of cloudy and rainy weather. Then, the output correlation of different power stations is analyzed to obtain PV stations with high output correlation as the horizontal reference, which is used to exclude interferences such as permanent faults at the power stations. At the same time, vertical comparison of the output curves of the station under test on different clear days is conducted to eliminate interference factors such as weather and environmental conditions. Subsequently, the metered active power output data, which is free from interference, is input into the QRRNN model to obtain the normal active power output range of the PV. The power threshold of the normal output range is utilized to identify anomalies in PV power generation. Finally, simulation analysis of actual PV system data is conducted, and the results show that the method can effectively identify PV power generation anomalies and has high accuracy in PV fault detection.
摘要：
To meet the stringent requirements of industrial applications, modern Ethernet datacenter networks widely deployed with remote direct memory access (RDMA) technology and priority-based flow control (PFC) scheme aim at providing low latency and high throughput transmission performance. However, the existing end-to-end congestion control cannot handle the transient congestion timely due to the round-trip-time (RTT) level control loop, inevitably resulting in PFC triggering. In this article, we propose a Sub-RTT congestion control mechanism called SRCC to alleviate bursty congestion timely. Specifically, SRCC identifies the congested flows accurately, notifies congestion directly from the hotspot to the corresponding source at the sub-RTT control loop and adjusts the sending rate to avoid PFC's head-of-line blocking. Compared to the state-of-the-art end-to-end transmission protocols, the evaluation results show that SRCC effectively reduces the average flow completion time (FCT) by up to 61%, 52%, 40%, and 24% over datacenter quantized congestion notification (DCQCN), Swift, high precision congestion control (HPCC), and photonic congestion notification (PCN), respectively.
期刊：
Journal of Materials Processing Technology,2025年:118909 ISSN：0924-0136
通讯作者：
Cong Mao<&wdkj&>Yongle Hu
作者机构：
College of Mechanical and Vehicle Engineering, Changsha University of Science and Technology, Changsha 410114, China;Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical Equipment, Changsha University of Science and Technology, Changsha 410114, China;[Jun Gong] Hunan Wuxin Tunnel Intelligent Equipment Co., Ltd., Changsha 410100, China;[Z.M. Bi] Department of Civil and Mechanical Engineering, Purdue University Fort Wayne, Fort Wayne, IN 46805, USA;[Dejia Zhang; Yongle Hu; Jien Guo; Mingjun Zhang; Wentao Wang; Yuanqiang Luo] College of Mechanical and Vehicle Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical Equipment, Changsha University of Science and Technology, Changsha 410114, China
通讯机构：
[Cong Mao; Yongle Hu] C;College of Mechanical and Vehicle Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical Equipment, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>College of Mechanical and Vehicle Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical Equipment, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Hunan Wuxin Tunnel Intelligent Equipment Co., Ltd., Changsha 410100, China
摘要：
Grinding-induced white and dark layers play a critical role in determining the surface integrity of hardened AISI 52100 steel. However, the atomic-scale formation mechanisms remain inadequately characterized. This study systematically investigated carbon redistribution governing the differentiation of superficial and subsurface layers, focusing on the interplay between carbon atom migration and localized structural transformations. Through FIB-TEM characterization, a competitive grain refinement pathway was deciphered within the white layer, and its nanocrystallization model was established. This model reflects adaptive grain evolution driven by dislocation slip, offering new perspectives on surface integrity regulation via multiscale analysis. Results revealed that grinding-induced superficial re-austenitization followed by rapid cooling caused carbon saturation in α -Fe lattices, which generated asymmetric distortion that promoted twinning-dominated martensitic transformation and formed a hardened white layer composed of acicular martensite grains. Subsurface regions with insufficient thermal input for austenitization underwent carbon desolvation during cooling, triggering significant relaxation of lattice distortion. This process enabled high-temperature tempering that generated a softened dark layer of over-tempered martensite and ferrite composites. Under the thermomechanical coupling effect, dislocation slips were accumulated within the workpiece surface microstructure. This led to a nanocrystallization model that progressively transitioned from dynamic recovery (DRV) to major continuous dynamic recrystallization (cDRX) supplemented by minor discontinuous dynamic recrystallization (dDRX). Meanwhile, the pinning effect of carbide particles enhanced dislocation proliferation and cross-slip. The synergistic interactions among these mechanisms resulted in substantial grain refinement down to the nanoscale. These findings provide valuable insights for optimizing grinding processes and improving the performance of machine elements.
Grinding-induced white and dark layers play a critical role in determining the surface integrity of hardened AISI 52100 steel. However, the atomic-scale formation mechanisms remain inadequately characterized. This study systematically investigated carbon redistribution governing the differentiation of superficial and subsurface layers, focusing on the interplay between carbon atom migration and localized structural transformations. Through FIB-TEM characterization, a competitive grain refinement pathway was deciphered within the white layer, and its nanocrystallization model was established. This model reflects adaptive grain evolution driven by dislocation slip, offering new perspectives on surface integrity regulation via multiscale analysis. Results revealed that grinding-induced superficial re-austenitization followed by rapid cooling caused carbon saturation in α -Fe lattices, which generated asymmetric distortion that promoted twinning-dominated martensitic transformation and formed a hardened white layer composed of acicular martensite grains. Subsurface regions with insufficient thermal input for austenitization underwent carbon desolvation during cooling, triggering significant relaxation of lattice distortion. This process enabled high-temperature tempering that generated a softened dark layer of over-tempered martensite and ferrite composites. Under the thermomechanical coupling effect, dislocation slips were accumulated within the workpiece surface microstructure. This led to a nanocrystallization model that progressively transitioned from dynamic recovery (DRV) to major continuous dynamic recrystallization (cDRX) supplemented by minor discontinuous dynamic recrystallization (dDRX). Meanwhile, the pinning effect of carbide particles enhanced dislocation proliferation and cross-slip. The synergistic interactions among these mechanisms resulted in substantial grain refinement down to the nanoscale. These findings provide valuable insights for optimizing grinding processes and improving the performance of machine elements.
通讯机构：
[Zhou, CJ ] G;Guangzhou Univ, Sch Civil Engn & Transportat, Guangzhou 510006, Peoples R China.
关键词：
urban rail transit ridership;land use;temporal heterogeneity;panel data analysis;transit-oriented development
摘要：
Understanding how land use affects urban rail transit (URT) ridership is essential for facilitating URT usage. While previous studies have explored the way that land use impacts URT ridership, few have figured out how this impact evolves over time. Utilizing URT turnstile and land use data in Beijing, we employed panel data analysis methods to verify the existence of the temporal heterogeneity of the impact and capture this temporal heterogeneity. The results identified time-varying impacts of land use on the URT boarding and alighting trips on weekdays and non-weekdays and also demonstrated the rationality of the mixed effects time-varying coefficient panel data (TVC-P) model in capturing this temporal heterogeneity accurately. The TVC-P model revealed how land use density appealed to URT commuting during weekday morning peak times, and how it triggered the generation of URT commutes during the weekday evening rush hours. The land use diversity promoted URT trips over an extended period on non-weekdays. Additionally, the study identified the time-varying impacts of specific land use on URT ridership. These insights provide both theoretical and empirical support for developing policies and actions that improve the efficiency of transportation systems and foster alignment between land use and transport.
期刊：
Journal of Solid State Chemistry,2025年345:125205 ISSN：0022-4596
通讯作者：
Huang, Jincheng;Peng, ZY
作者机构：
[Huang, Jincheng; Zhu, Yuxiang; Zhang, Yuanfang; Peng, Zhuoyin; Zhang, Xinlong; Li, Wei; Liao, Kai; Peng, ZY; Gu, Yongjie] Changsha Univ Sci & Technol, Hunan Prov Collaborat Innovat Ctr Clean Energy & S, Sch Energy & Power Engn, Educ Dept Hunan Prov, Changsha 410111, Peoples R China.;[Zhu, Yuxiang] Wuxi Municipal Bur Ind & Informat Technol, Wuxi, Peoples R China.
通讯机构：
[Huang, JC; Peng, ZY ] C;Changsha Univ Sci & Technol, Hunan Prov Collaborat Innovat Ctr Clean Energy & S, Sch Energy & Power Engn, Educ Dept Hunan Prov, Changsha 410111, Peoples R China.
关键词：
Carbon based PbS quantum dot solar cells;Direct one-step dual ligand passivation;Charge transfer;Photovoltaic performance
摘要：
The surface traps of quantum dots are still serious problems to limit the photovoltaic performance of carbon based quantum dot solar cells. In order to optimize the surface state of quantum dot solar cells, PbI 2 /MPA dual surface ligand is introduced for direct one-step surface passivation strategy to reduce the generated undercoordinated sites and OH group in PbS quantum dot solar cells, which can provide uniform, compact and stable structure for PbS thin films. The optical absorption and charge separation properties of carbon based PbS quantum dot solar cells have been improved under this PbI 2 /MPA dual surface ligand passivation process. The excellent trap passivation has effectively improved the charge transfer efficiency of the solar cells, which exhibits higher open-circuit voltage (25.33 mA/cm 2 ), short-circuit current density (507.8 mV) and fill factor (0.525) value for carbon based PbS quantum dot solar cells. As a result, photovoltaic conversion efficiency of carbon based PbS quantum dot solar cells has been enhanced from 5.36 % to 6.75 % under this direct one-step dual PbI 2 /MPA surface ligand passivation. This work provides an effective traps passivation process to further optimize the PbS quantum dots for optoelectronic devices applications.
The surface traps of quantum dots are still serious problems to limit the photovoltaic performance of carbon based quantum dot solar cells. In order to optimize the surface state of quantum dot solar cells, PbI 2 /MPA dual surface ligand is introduced for direct one-step surface passivation strategy to reduce the generated undercoordinated sites and OH group in PbS quantum dot solar cells, which can provide uniform, compact and stable structure for PbS thin films. The optical absorption and charge separation properties of carbon based PbS quantum dot solar cells have been improved under this PbI 2 /MPA dual surface ligand passivation process. The excellent trap passivation has effectively improved the charge transfer efficiency of the solar cells, which exhibits higher open-circuit voltage (25.33 mA/cm 2 ), short-circuit current density (507.8 mV) and fill factor (0.525) value for carbon based PbS quantum dot solar cells. As a result, photovoltaic conversion efficiency of carbon based PbS quantum dot solar cells has been enhanced from 5.36 % to 6.75 % under this direct one-step dual PbI 2 /MPA surface ligand passivation. This work provides an effective traps passivation process to further optimize the PbS quantum dots for optoelectronic devices applications.
摘要：
Bridge steel, frequently employed in cross-sea bridge construction, exhibits excellent weldability, superior strength, and toughness. The service life and stability of steel structures are influenced by the presence of corrosive ions within marine environments, necessitating an in-depth examination of the corrosion mechanisms affecting bridge steel. In this study, Q370qD bridge steel was subjected to heat treatment to evaluate the influence of microstructural variations on its corrosion behavior. The microstructure of untreated steel (alloy F) predominantly consists of granular ferrite. Subsequent high-temperature heat treatment induces a partial transformation in the steel microstructure (alloy A), yielding lath carbide-free bainite. Post-immersion tests show both alloy surfaces densely covered with gamma-FeOOH, alpha-FeOOH, and a mixture of Fe3O4 and Fe2O3. Over time, gamma-FeOOH undergoes partial conversion into the more stable alpha-FeOOH form, enhancing the protective barrier against the matrix for both alloys. Alloy F exhibits a significant reduction in corrosion rate compared to alloy A. The proportion of alpha-FeOOH in alloy A initially decreases then increases with prolonged exposure, while in alloy F, it consistently rises. The corrosion resistance of alloy A surpasses that of alloy F, which is attributed to the lath-shaped carbide-free bainite's effectiveness in obstructing Cl- penetration and thereby improving corrosion resistance.
