This study examines the water-use efficiency and conservation potential of Guangzhou Railway Polytechnic(GRP)using an integrated methodology that combines water balance testing,functional-zone diagnostics,and behavior...This study examines the water-use efficiency and conservation potential of Guangzhou Railway Polytechnic(GRP)using an integrated methodology that combines water balance testing,functional-zone diagnostics,and behavioral surveys conducted between 2022 and 2024.Technical results show robust performance,with per capita consumption averaging 32.83 m3/person∙year—far below the provincial benchmark of 80 m3—and a distribution-network leakage rate of 3.5%.Functional-zone analysis identifies dormitories(44.9%)and laboratory/practical buildings(20.9%)as the dominant water-use areas,underscoring the need for zone-specific strategies.Behavioral findings reveal that although students and faculty exhibit high awareness and positive conservation attitudes,students demonstrate weaker behavioral execution and limited familiarity with institutional policies(62.8%),contributing to elevated residential consumption.Drawing on the Theory of Planned Behavior and Triple-Loop Learning,the study concludes that while GRP has established a strong technical and governance foundation,further gains depend on digital monitoring,differentiated management,and targeted behavioral interventions.These findings provide actionable insights for developing data-driven and behavior-responsive water management systems in vocational institutions.展开更多
The silt soft soil in Nansha District of Guangzhou was the softest soft soil in China. It had the characteristics of high natural water content, high compressibility, long consolidation time, and complex layered distr...The silt soft soil in Nansha District of Guangzhou was the softest soft soil in China. It had the characteristics of high natural water content, high compressibility, long consolidation time, and complex layered distribution of soil layers. These characteristics formed the clogging characteristics of silt soft soil, which greatly increased the construction difficulty and hindered the construction progress. Therefore, based on the basic physical and mechanical properties of silt soft soil in Nansha District of Guangzhou, this paper evaluated the clogging characteristics of three silt soft soil areas in Nansha District of Guangzhou through long-term permeability test, and carried out scanning electron microscope test to explore the influence of different parameters and microstructure on the clogging difficulty of silt soft soil. The results showed that the silt soft soil Zone I and Zone II (shallow layer) in Nansha District of Guangzhou were divided into slight siltation levels, and the silt soft soil Zone III (deep layer) was mild siltation level. Large pores were widely distributed in shallow silt soft soil, while the continuity of large pores in deep silt soft soil was poor. The migration of fine particles that failed to establish contact with surrounding particles in the soil blocks the small pores of seepage and thus produces siltation.展开更多
As light metals,aluminum and magnesium have been widely used in automotive manufacturing,but the welding of Al/Mg joints is facing challenges.However,it is difficult to obtain high-quality aluminum/magnesium joints wi...As light metals,aluminum and magnesium have been widely used in automotive manufacturing,but the welding of Al/Mg joints is facing challenges.However,it is difficult to obtain high-quality aluminum/magnesium joints with traditional arc welding methods.As a solid-phase welding technology,ultrasonic metal welding has the characteristics of high welding efficiency and less welded defects.It is also suitable for welding sound metal bonds.Aluminum and magnesium ultrasonic welding has become a research hotspot.Therefore,the evolution of microstructures and mechanical performance of Al/Mg and multi-layer Al/Mg ultrasonic welding,and the new study works,including the molecular dynamic simulation of Al/Mg ultrasonic welding and hybrid based on ultrasonic welding are summarized.Furthermore,several promising research directions are proposed to guide in-depth investigations into the ultrasonic welding of Al/Mg dissimilar joints.展开更多
Prediction of water inflow into a tunnel is a crucial prerequisite for the waterproof and drainage design of mountain tunnels in water-rich areas.Based on the proposed Baiyun Mountain Tunnel project in Guangzhou,a num...Prediction of water inflow into a tunnel is a crucial prerequisite for the waterproof and drainage design of mountain tunnels in water-rich areas.Based on the proposed Baiyun Mountain Tunnel project in Guangzhou,a numerical percolation model of random fractured rock of a tunnel underpassing a water reservoir is established to study the seepage characteristics of surrounding rock,the law of water inflow,and the change of lining water pressure,considering the local artificial boundary conditions for seepage in large rock mass,.In addition,the influences of rock permeability,fracture aperture,grouting circle thickness,and penetration are analyzed.The results show that:(1)Only fractures with aperture wider than 0.1 mm can play a significant role in water conduction in rocks with the permeability lower than 10^(-11)m^(2);(2)The greater the permeability difference between the fractures and rocks,the more remarkable the effects of fractures on the surrounding rock seepage field and cavern water inflow;(3)The sensitivity of grouting waterproof function to grouting circle thickness,grouting ring penetration,and rock permeability is significantly higher than that of tunnel buried depth and fracture aperture;(4)The lining water head is much more sensitive to the grouting circle thickness and penetration than to the tunnel buried depth;(5)With the grouting range enlarging,the impact of grouting circle permeability on the precipitation pressure role of the grouting ring increases;(6)For the interesting tunnel designed to be built at the depth of 70 m,the grouting circle with the thickness of 0.5 m and permeability of 10-^(14)m^(2)is recommended.展开更多
As the dominant seepage channel in rock masses,it is of great significance to study the influence of fracture roughness distribution on seepage and heat transfer in rock masses.In this paper,the fracture roughness dis...As the dominant seepage channel in rock masses,it is of great significance to study the influence of fracture roughness distribution on seepage and heat transfer in rock masses.In this paper,the fracture roughness distribution functions of the Bakhtiary dam site and Oskarshamn/Forsmark mountain were fitted using statistical methods.The COMSOL Multiphysics finite element software was utilized to analyze the effects of fracture roughness distribution types and empirical formulas for fracture hydraulic aperture on the seepage field and temperature field of rock masses.The results show that:(1)The fracture roughness at the Bakhtiary dam site and Oskarshamn/Forsmark mountain follows lognormal and normal distributions,respectively;(2)For rock masses with the same expected value and standard deviation of fracture roughness,the outflow from rock masses with lognormal distribution of fracture roughness is significantly larger than that of rock masses with normal distribution of fracture roughness;(3)The fracture hydraulic aperture,outflow,and cold front distance of the Li and Jiang model are significantly larger than those of the Barton model;(4)The outflow,hydraulic pressure distribution,and temperature distribution of the Barton model are more sensitive to the fracture roughness distribution type than those of the Li and Jiang model.展开更多
Higher education is transitioning from mass expansion to high-quality development.In this process,mental health issues among college students have become increasingly prominent,encompassing not only academic stress-in...Higher education is transitioning from mass expansion to high-quality development.In this process,mental health issues among college students have become increasingly prominent,encompassing not only academic stress-induced anxiety but also complex challenges such as interpersonal adaptation difficulties and career planning confusion.Traditional“problem-oriented”intervention models have shown limitations in responsiveness and adaptability,often only passively addressing existing psychological crises rather than preventing them in advance.This study aims to explore an AI-powered“positive psychology”proactive intervention model through developing an intelligent system.The system automatically collects,filters,and personalizes recommendations for positive activities on campus.Using a randomized controlled trial design,we conducted an 8-week intervention study involving 126 college students at a university.The study found that AI-based“campus positive activity”recommendations effectively boost students’positive emotions and promote psychological capital development through cumulative micro-interventions.This provides universities with empirical evidence and innovative methods to implement low-cost,efficient,and scalable mental health promotion programs through smart technology.展开更多
Multispectral imaging plays a crucial role in simultaneously capturing detailed spatial and spectral information,which is fundamental for understanding complex phenomena across various domains.Traditional systems face...Multispectral imaging plays a crucial role in simultaneously capturing detailed spatial and spectral information,which is fundamental for understanding complex phenomena across various domains.Traditional systems face significant challenges,such as large volume,static function,and limited wavelength selectivity.Here,we propose an innovative dynamic reflective multispectral imaging system via a thermally responsive cholesteric liquid crystal based planar lens.By employing advanced photoalignment technology,the phase distribution of a lens is imprinted to the liquid crystal director.The reflection band is reversibly tuned from 450 nm to 750 nm by thermally controlling the helical pitch of the cholesteric liquid crystal,allowing selectively capturing images in different colors.This capability increases imaging versatility,showing great potential in precision agriculture for assessing crop health,noninvasive diagnostics in healthcare,and advanced remote sensing for environmental monitoring.展开更多
Magnesium(Mg)has great potential for application in the automotive and aerospace sectors due to its abundant resources and low density.However,the industrial applications of Mg alloys are far below alu-minum alloys.At...Magnesium(Mg)has great potential for application in the automotive and aerospace sectors due to its abundant resources and low density.However,the industrial applications of Mg alloys are far below alu-minum alloys.At present,most commercial Mg alloys exhibit a low yield strength of<300 MPa,and their specific strength does not exhibit an advantage over that of aluminum alloys and high-strength steels.Improving the strength of Mg alloys is one of the key topics in this field.In the past two decades,high-strength Mg alloys made by powder metallurgy and severe plastic deformation techniques have been reported,but the small sample dimension and high-cost limit their industrial production.Extru-sion can be used to fabricate bulk materials with fine-grained microstructures and improved mechanical properties,which is considered as a suitable route of producing high-strength Mg alloys at the indus-trial level.In this review,recent advances in the extrusion of different Mg alloys are briefly summa-rized,including commercial Mg alloys,high-alloyed Mg-RE alloys,and Ca-containing Mg alloys.Different strengthening strategies,including alloying,grain refinement,texture modification,etc.,are employed in developing high-strength Mg alloys,with special attention to a novel strengthening mechanism,namely hetero-deformation-induced strengthening,which has recently been applied to simultaneously improve the strength and ductility of Mg alloys.Therefore,the heterostructured Mg alloys prepared by extrusion are also introduced in this work,and the influences of alloying elements and extrusion parameters on the preparation of heterostructured Mg alloys are discussed systematically.Furthermore,this review summa-rizes the effect of post-extrusion treatment on the mechanical properties of extruded Mg alloys,along with a brief comparison of the mechanical properties between Mg and Al alloys.Finally,some poten-tial research directions for further advancing the high-performance and low-cost extruded Mg alloys are suggested.展开更多
A large-scale Mg-6Al-Zn plate was prepared by multi-pass submerged friction stir processing(M-SFSP)and its superplastic deformation behavior was investigated.The maximum elongation of 467%,332%and 421%was attained for...A large-scale Mg-6Al-Zn plate was prepared by multi-pass submerged friction stir processing(M-SFSP)and its superplastic deformation behavior was investigated.The maximum elongation of 467%,332%and 421%was attained for the samples oriented in the processing direction(PD),45°tilted toward the PD,and transverse direction(TD),respectively,when deformed at 623 K and a strain rate of 1×10^(−3) s^(−1).This was attributed to the homogeneous and fine-grained structure with mostly high-angle grain boundaries facilitating the prevalent deformation mechanism of grain boundary sliding,along with the weakened texture and dynamic recrystallization during hot deformation.展开更多
In China, systemic techno-economic analysis for solar tracker has been absent. To fill the blank, by taking the economic analysis of solar tracker application as the research object and using the LCOE method widely us...In China, systemic techno-economic analysis for solar tracker has been absent. To fill the blank, by taking the economic analysis of solar tracker application as the research object and using the LCOE method widely used internationally, the techno-economic analysis model of solar tracker was established according to conditions in China. Influence factors on LCOE were analyzed by using the established model, and the relationship between each cost factor and the cost component of energy leveling of tracker was further studied. In addition, the calculation method of investment payback period based on energy leveling analysis was established, and the influence of various factors on investment payback period was revealed through an example calculation. The research results will help to measure the economy of tracker application more accurately and comprehensively, and promote the popularization and application of solar tracker. The economic analysis model of solar tracker application was established by using LCOE method. The influence factors and cost component of LCOE were analyzed with the model. The payback period of solar tracker investment was also analyzed based on LCOE method.展开更多
In view of class imbalance in data-driven modeling for Prognostics and Health Management(PHM),existing classification methods may fail in generating effective fault prediction models for the on-board high-speed train ...In view of class imbalance in data-driven modeling for Prognostics and Health Management(PHM),existing classification methods may fail in generating effective fault prediction models for the on-board high-speed train control equipment.A virtual sample generation solution based on Generative Adversarial Network(GAN)is proposed to overcome this shortcoming.Aiming at augmenting the sample classes with the imbalanced data problem,the GAN-based virtual sample generation strategy is embedded into the establishment of fault prediction models.Under the PHM framework of the on-board train control system,the virtual sample generation principle and the detailed procedures are presented.With the enhanced class-balancing mechanism and the designed sample augmentation logic,the PHM scheme of the on-board train control equipment has powerful data condition adaptability and can effectively predict the fault probability and life cycle status.Practical data from a specific type of on-board train control system is employed for the validation of the presented solution.The comparative results indicate that GAN-based sample augmentation is capable of achieving a desirable sample balancing level and enhancing the performance of correspondingly derived fault prediction models for the Condition-based Maintenance(CBM)operations.展开更多
With the rapid development of global transportation track equipment, the running speed of modern rail transit equipment keeps refreshing records. High-speed EMUs, inter-city EMUs and urban rail vehicles have become th...With the rapid development of global transportation track equipment, the running speed of modern rail transit equipment keeps refreshing records. High-speed EMUs, inter-city EMUs and urban rail vehicles have become the main types of domestic passenger transport vehicles, especially the lightweight production and manufacture of high-speed EMUs and urban rail vehicles, which are the main topics of railway transport modernization research and discussion. Track manufacturing is a successful example of China's industrial transformation and strategic restructuring through systematic innovation since the reform and opening up. In this paper, the application of some advanced manufacturing technologies in the track equipment manufacturing industry and the opportunities and challenges faced by the whole track equipment manufacturing industry were mainly studied, hoping to provide some help for the development of the track equipment manufacturing industry in China.展开更多
Phase transformation is one of the factors that would significantly influence the ability to resist cavitation erosion of stainless steels. Due to the specific properties of duplex stainless steel, the heat treatment ...Phase transformation is one of the factors that would significantly influence the ability to resist cavitation erosion of stainless steels. Due to the specific properties of duplex stainless steel, the heat treatment would bring about significant phase transformations. In this paper, we have examined the previous studies on the phase transition of stainless steel, including the literature on the classification of stainless steel, spinodal decomposition, sigma phase transformation, and cavitation erosion of double stainless steel. Through these literature investigations, the destruction of cavitation erosion on duplex stainless steel can be clearly known, and the causes of failure of duplex stainless steel in seawater can be clarified, thus providing a theoretical basis for subsequent scientific research. And the review is about to help assess the possibility of using bulk heat treatment to improve the cavitation erosion (CE) behaviour of the duplex stainless steel 7MoPLUS.展开更多
The rapid development of the electronic information industry brings to the irreplaceable role of electronic components, therefore the search of a more reliable packaging material has become increasingly important. In ...The rapid development of the electronic information industry brings to the irreplaceable role of electronic components, therefore the search of a more reliable packaging material has become increasingly important. In the electronic packaging system, the failure phenomenon caused by residual stress is one of the key factors restricting the development of electronic packaging technology. In order to use the in-situ characterization technology to explore the residual stress inducing mechanism and failure mechanism of epoxy-based advanced packaging materials, this paper gives a review of related previous research, and lays a theoretical foundation for the upcoming research. The classification and generation mechanism of residual stress are clarified in this paper, which provides data support for future related research.展开更多
Pore water pressure fluctuations are an inherent phenomenon during the consolidation process of clayey foundations, and understanding its mechanism is crucial for comprehending the consolidation process and addressing...Pore water pressure fluctuations are an inherent phenomenon during the consolidation process of clayey foundations, and understanding its mechanism is crucial for comprehending the consolidation process and addressing issues such as drainage blockage during consolidation. This study investigates the consolidation behavior of clay, particularly focusing on pore water pressure fluctuations during the consolidation process of dredged marine sedimentary mud from Daya Bay, Guangdong Province. Given the prevalent use of clay in large-scale construction projects in southern China, understanding the factors influencing pore water pressure is crucial for optimizing consolidation times and improving construction efficacy. Using a custom vacuum preloading model, the research explores the impact of sodium hydroxide on the bound water content and its subsequent effects on pore water pressure dynamics. Experimental findings reveal a distinct inflection point in pore water pressure dissipation, suggesting that particle migration and bound water interactions contribute to the observed fluctuations. These results provide valuable insights for enhancing engineering applications in clay consolidation and mitigating drainage issues, ultimately informing construction practices and reducing project timelines.展开更多
In today’s era,with the increase in the number of enterprise innovations,enterprises must adopt project portfolio management for various innovations,select alternative projects from the perspective of enterprise stra...In today’s era,with the increase in the number of enterprise innovations,enterprises must adopt project portfolio management for various innovations,select alternative projects from the perspective of enterprise strategy.This paper primarily explores the use of project portfolio management in enterprise project management,hoping to improve the quality of enterprise project management and the utilization efficiency of project portfolio management in enterprise project management.展开更多
As the core carrier of Lingnan culture and a nationally famous historical&cultural city,Guangzhou preserves more than 3000 immovable historic buildings,including arcade rows,ancestral halls,Xiguan mansions and mod...As the core carrier of Lingnan culture and a nationally famous historical&cultural city,Guangzhou preserves more than 3000 immovable historic buildings,including arcade rows,ancestral halls,Xiguan mansions and modern public edifices.Their brick-timber hybrid structures,high-density“bambootube”street pattern and hot-humid subtropical climate create unique fire challenges.This study systematically summarizes an“inherent-acquired-environmental”superimposed fire-risk mechanism.By integrating traditional Cantonese fire-resistance wisdom—such as Qingyun fire lanes,wok-ear gables and courtyard smoke vents—and heritage-friendly innovations,a three-level policy-technology-management protection framework is established.Hierarchical protection aligned with value grading,life-cycle technology pathways and multistakeholder collaboration is proposed.The“minimum-intervention and performance-based”route and the“regulation-guideline-standard”policy loop developed by Guangzhou reduce the fire incidence of priority historic buildings while retaining heritage authenticity,offering a replicable paradigm for balancing fire safety and conservation in hot-humid,high-density contexts.展开更多
文摘This study examines the water-use efficiency and conservation potential of Guangzhou Railway Polytechnic(GRP)using an integrated methodology that combines water balance testing,functional-zone diagnostics,and behavioral surveys conducted between 2022 and 2024.Technical results show robust performance,with per capita consumption averaging 32.83 m3/person∙year—far below the provincial benchmark of 80 m3—and a distribution-network leakage rate of 3.5%.Functional-zone analysis identifies dormitories(44.9%)and laboratory/practical buildings(20.9%)as the dominant water-use areas,underscoring the need for zone-specific strategies.Behavioral findings reveal that although students and faculty exhibit high awareness and positive conservation attitudes,students demonstrate weaker behavioral execution and limited familiarity with institutional policies(62.8%),contributing to elevated residential consumption.Drawing on the Theory of Planned Behavior and Triple-Loop Learning,the study concludes that while GRP has established a strong technical and governance foundation,further gains depend on digital monitoring,differentiated management,and targeted behavioral interventions.These findings provide actionable insights for developing data-driven and behavior-responsive water management systems in vocational institutions.
文摘The silt soft soil in Nansha District of Guangzhou was the softest soft soil in China. It had the characteristics of high natural water content, high compressibility, long consolidation time, and complex layered distribution of soil layers. These characteristics formed the clogging characteristics of silt soft soil, which greatly increased the construction difficulty and hindered the construction progress. Therefore, based on the basic physical and mechanical properties of silt soft soil in Nansha District of Guangzhou, this paper evaluated the clogging characteristics of three silt soft soil areas in Nansha District of Guangzhou through long-term permeability test, and carried out scanning electron microscope test to explore the influence of different parameters and microstructure on the clogging difficulty of silt soft soil. The results showed that the silt soft soil Zone I and Zone II (shallow layer) in Nansha District of Guangzhou were divided into slight siltation levels, and the silt soft soil Zone III (deep layer) was mild siltation level. Large pores were widely distributed in shallow silt soft soil, while the continuity of large pores in deep silt soft soil was poor. The migration of fine particles that failed to establish contact with surrounding particles in the soil blocks the small pores of seepage and thus produces siltation.
基金supported by Key Projects of Science and Technology Research Plan of Hubei Provincial Department of Education(D20221306)the National Natural Science Foundation of China(51605103)Key Project of Hubei Provincial Science and Technology Department(2020BAB055).
文摘As light metals,aluminum and magnesium have been widely used in automotive manufacturing,but the welding of Al/Mg joints is facing challenges.However,it is difficult to obtain high-quality aluminum/magnesium joints with traditional arc welding methods.As a solid-phase welding technology,ultrasonic metal welding has the characteristics of high welding efficiency and less welded defects.It is also suitable for welding sound metal bonds.Aluminum and magnesium ultrasonic welding has become a research hotspot.Therefore,the evolution of microstructures and mechanical performance of Al/Mg and multi-layer Al/Mg ultrasonic welding,and the new study works,including the molecular dynamic simulation of Al/Mg ultrasonic welding and hybrid based on ultrasonic welding are summarized.Furthermore,several promising research directions are proposed to guide in-depth investigations into the ultrasonic welding of Al/Mg dissimilar joints.
文摘Prediction of water inflow into a tunnel is a crucial prerequisite for the waterproof and drainage design of mountain tunnels in water-rich areas.Based on the proposed Baiyun Mountain Tunnel project in Guangzhou,a numerical percolation model of random fractured rock of a tunnel underpassing a water reservoir is established to study the seepage characteristics of surrounding rock,the law of water inflow,and the change of lining water pressure,considering the local artificial boundary conditions for seepage in large rock mass,.In addition,the influences of rock permeability,fracture aperture,grouting circle thickness,and penetration are analyzed.The results show that:(1)Only fractures with aperture wider than 0.1 mm can play a significant role in water conduction in rocks with the permeability lower than 10^(-11)m^(2);(2)The greater the permeability difference between the fractures and rocks,the more remarkable the effects of fractures on the surrounding rock seepage field and cavern water inflow;(3)The sensitivity of grouting waterproof function to grouting circle thickness,grouting ring penetration,and rock permeability is significantly higher than that of tunnel buried depth and fracture aperture;(4)The lining water head is much more sensitive to the grouting circle thickness and penetration than to the tunnel buried depth;(5)With the grouting range enlarging,the impact of grouting circle permeability on the precipitation pressure role of the grouting ring increases;(6)For the interesting tunnel designed to be built at the depth of 70 m,the grouting circle with the thickness of 0.5 m and permeability of 10-^(14)m^(2)is recommended.
基金College Students Innovation and Entrepreneurship Project of Guangzhou Railway Polytechnic(2025CXCY015)。
文摘As the dominant seepage channel in rock masses,it is of great significance to study the influence of fracture roughness distribution on seepage and heat transfer in rock masses.In this paper,the fracture roughness distribution functions of the Bakhtiary dam site and Oskarshamn/Forsmark mountain were fitted using statistical methods.The COMSOL Multiphysics finite element software was utilized to analyze the effects of fracture roughness distribution types and empirical formulas for fracture hydraulic aperture on the seepage field and temperature field of rock masses.The results show that:(1)The fracture roughness at the Bakhtiary dam site and Oskarshamn/Forsmark mountain follows lognormal and normal distributions,respectively;(2)For rock masses with the same expected value and standard deviation of fracture roughness,the outflow from rock masses with lognormal distribution of fracture roughness is significantly larger than that of rock masses with normal distribution of fracture roughness;(3)The fracture hydraulic aperture,outflow,and cold front distance of the Li and Jiang model are significantly larger than those of the Barton model;(4)The outflow,hydraulic pressure distribution,and temperature distribution of the Barton model are more sensitive to the fracture roughness distribution type than those of the Li and Jiang model.
文摘Higher education is transitioning from mass expansion to high-quality development.In this process,mental health issues among college students have become increasingly prominent,encompassing not only academic stress-induced anxiety but also complex challenges such as interpersonal adaptation difficulties and career planning confusion.Traditional“problem-oriented”intervention models have shown limitations in responsiveness and adaptability,often only passively addressing existing psychological crises rather than preventing them in advance.This study aims to explore an AI-powered“positive psychology”proactive intervention model through developing an intelligent system.The system automatically collects,filters,and personalizes recommendations for positive activities on campus.Using a randomized controlled trial design,we conducted an 8-week intervention study involving 126 college students at a university.The study found that AI-based“campus positive activity”recommendations effectively boost students’positive emotions and promote psychological capital development through cumulative micro-interventions.This provides universities with empirical evidence and innovative methods to implement low-cost,efficient,and scalable mental health promotion programs through smart technology.
基金supported by the National Key Research and Development Program of China(No.2022YFA1203700)the National Natural Science Foundation of China(NSFC)(Nos.62405129 and 62035008)+1 种基金the University Research Project of Guangzhou Education Bureau(No.202235053)the Natural Science Foundation of Jiangsu Province(No.BK20241197).
文摘Multispectral imaging plays a crucial role in simultaneously capturing detailed spatial and spectral information,which is fundamental for understanding complex phenomena across various domains.Traditional systems face significant challenges,such as large volume,static function,and limited wavelength selectivity.Here,we propose an innovative dynamic reflective multispectral imaging system via a thermally responsive cholesteric liquid crystal based planar lens.By employing advanced photoalignment technology,the phase distribution of a lens is imprinted to the liquid crystal director.The reflection band is reversibly tuned from 450 nm to 750 nm by thermally controlling the helical pitch of the cholesteric liquid crystal,allowing selectively capturing images in different colors.This capability increases imaging versatility,showing great potential in precision agriculture for assessing crop health,noninvasive diagnostics in healthcare,and advanced remote sensing for environmental monitoring.
基金sponsored by the Key-Area Research and De-velopment Program of Guangdong Province(No.2020B010186002)the Natural Science Foundation of Guangdong for Research Team(No.2015A030312003)+2 种基金the Yangcheng Scholars Research Project of Guangzhou Education Bureau(No.202032806)Daolun Chen is grateful for the financial support from the Natural Sci-ences and Engineering Research Council of Canada(NSERC)Hua Wang thanks the Study Abroad Fund for supporting his study at Toronto Metropolitan University。
文摘Magnesium(Mg)has great potential for application in the automotive and aerospace sectors due to its abundant resources and low density.However,the industrial applications of Mg alloys are far below alu-minum alloys.At present,most commercial Mg alloys exhibit a low yield strength of<300 MPa,and their specific strength does not exhibit an advantage over that of aluminum alloys and high-strength steels.Improving the strength of Mg alloys is one of the key topics in this field.In the past two decades,high-strength Mg alloys made by powder metallurgy and severe plastic deformation techniques have been reported,but the small sample dimension and high-cost limit their industrial production.Extru-sion can be used to fabricate bulk materials with fine-grained microstructures and improved mechanical properties,which is considered as a suitable route of producing high-strength Mg alloys at the indus-trial level.In this review,recent advances in the extrusion of different Mg alloys are briefly summa-rized,including commercial Mg alloys,high-alloyed Mg-RE alloys,and Ca-containing Mg alloys.Different strengthening strategies,including alloying,grain refinement,texture modification,etc.,are employed in developing high-strength Mg alloys,with special attention to a novel strengthening mechanism,namely hetero-deformation-induced strengthening,which has recently been applied to simultaneously improve the strength and ductility of Mg alloys.Therefore,the heterostructured Mg alloys prepared by extrusion are also introduced in this work,and the influences of alloying elements and extrusion parameters on the preparation of heterostructured Mg alloys are discussed systematically.Furthermore,this review summa-rizes the effect of post-extrusion treatment on the mechanical properties of extruded Mg alloys,along with a brief comparison of the mechanical properties between Mg and Al alloys.Finally,some poten-tial research directions for further advancing the high-performance and low-cost extruded Mg alloys are suggested.
基金sponsored by the National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials Open Fund(No.2020009)the Natural Science Foundation of Guangdong Universities for Innovative Team(No.2020KCXTD043)+1 种基金the Natural Sciences and Engineering Research Council of Canada(NSERC)in the form of international research collaborationNSERC-Alberta Innovates for the financial support。
文摘A large-scale Mg-6Al-Zn plate was prepared by multi-pass submerged friction stir processing(M-SFSP)and its superplastic deformation behavior was investigated.The maximum elongation of 467%,332%and 421%was attained for the samples oriented in the processing direction(PD),45°tilted toward the PD,and transverse direction(TD),respectively,when deformed at 623 K and a strain rate of 1×10^(−3) s^(−1).This was attributed to the homogeneous and fine-grained structure with mostly high-angle grain boundaries facilitating the prevalent deformation mechanism of grain boundary sliding,along with the weakened texture and dynamic recrystallization during hot deformation.
文摘In China, systemic techno-economic analysis for solar tracker has been absent. To fill the blank, by taking the economic analysis of solar tracker application as the research object and using the LCOE method widely used internationally, the techno-economic analysis model of solar tracker was established according to conditions in China. Influence factors on LCOE were analyzed by using the established model, and the relationship between each cost factor and the cost component of energy leveling of tracker was further studied. In addition, the calculation method of investment payback period based on energy leveling analysis was established, and the influence of various factors on investment payback period was revealed through an example calculation. The research results will help to measure the economy of tracker application more accurately and comprehensively, and promote the popularization and application of solar tracker. The economic analysis model of solar tracker application was established by using LCOE method. The influence factors and cost component of LCOE were analyzed with the model. The payback period of solar tracker investment was also analyzed based on LCOE method.
基金supported by National Natural Science Foundation of China(U2268206,T2222015)Beijing Natural Science Foundation(4232031)+1 种基金Key Fields Project of DEGP(2021ZDZX1110)Shenzhen Science and Technology Program(CJGJZD20220517141801004).
文摘In view of class imbalance in data-driven modeling for Prognostics and Health Management(PHM),existing classification methods may fail in generating effective fault prediction models for the on-board high-speed train control equipment.A virtual sample generation solution based on Generative Adversarial Network(GAN)is proposed to overcome this shortcoming.Aiming at augmenting the sample classes with the imbalanced data problem,the GAN-based virtual sample generation strategy is embedded into the establishment of fault prediction models.Under the PHM framework of the on-board train control system,the virtual sample generation principle and the detailed procedures are presented.With the enhanced class-balancing mechanism and the designed sample augmentation logic,the PHM scheme of the on-board train control equipment has powerful data condition adaptability and can effectively predict the fault probability and life cycle status.Practical data from a specific type of on-board train control system is employed for the validation of the presented solution.The comparative results indicate that GAN-based sample augmentation is capable of achieving a desirable sample balancing level and enhancing the performance of correspondingly derived fault prediction models for the Condition-based Maintenance(CBM)operations.
文摘With the rapid development of global transportation track equipment, the running speed of modern rail transit equipment keeps refreshing records. High-speed EMUs, inter-city EMUs and urban rail vehicles have become the main types of domestic passenger transport vehicles, especially the lightweight production and manufacture of high-speed EMUs and urban rail vehicles, which are the main topics of railway transport modernization research and discussion. Track manufacturing is a successful example of China's industrial transformation and strategic restructuring through systematic innovation since the reform and opening up. In this paper, the application of some advanced manufacturing technologies in the track equipment manufacturing industry and the opportunities and challenges faced by the whole track equipment manufacturing industry were mainly studied, hoping to provide some help for the development of the track equipment manufacturing industry in China.
文摘Phase transformation is one of the factors that would significantly influence the ability to resist cavitation erosion of stainless steels. Due to the specific properties of duplex stainless steel, the heat treatment would bring about significant phase transformations. In this paper, we have examined the previous studies on the phase transition of stainless steel, including the literature on the classification of stainless steel, spinodal decomposition, sigma phase transformation, and cavitation erosion of double stainless steel. Through these literature investigations, the destruction of cavitation erosion on duplex stainless steel can be clearly known, and the causes of failure of duplex stainless steel in seawater can be clarified, thus providing a theoretical basis for subsequent scientific research. And the review is about to help assess the possibility of using bulk heat treatment to improve the cavitation erosion (CE) behaviour of the duplex stainless steel 7MoPLUS.
文摘The rapid development of the electronic information industry brings to the irreplaceable role of electronic components, therefore the search of a more reliable packaging material has become increasingly important. In the electronic packaging system, the failure phenomenon caused by residual stress is one of the key factors restricting the development of electronic packaging technology. In order to use the in-situ characterization technology to explore the residual stress inducing mechanism and failure mechanism of epoxy-based advanced packaging materials, this paper gives a review of related previous research, and lays a theoretical foundation for the upcoming research. The classification and generation mechanism of residual stress are clarified in this paper, which provides data support for future related research.
文摘Pore water pressure fluctuations are an inherent phenomenon during the consolidation process of clayey foundations, and understanding its mechanism is crucial for comprehending the consolidation process and addressing issues such as drainage blockage during consolidation. This study investigates the consolidation behavior of clay, particularly focusing on pore water pressure fluctuations during the consolidation process of dredged marine sedimentary mud from Daya Bay, Guangdong Province. Given the prevalent use of clay in large-scale construction projects in southern China, understanding the factors influencing pore water pressure is crucial for optimizing consolidation times and improving construction efficacy. Using a custom vacuum preloading model, the research explores the impact of sodium hydroxide on the bound water content and its subsequent effects on pore water pressure dynamics. Experimental findings reveal a distinct inflection point in pore water pressure dissipation, suggesting that particle migration and bound water interactions contribute to the observed fluctuations. These results provide valuable insights for enhancing engineering applications in clay consolidation and mitigating drainage issues, ultimately informing construction practices and reducing project timelines.
文摘In today’s era,with the increase in the number of enterprise innovations,enterprises must adopt project portfolio management for various innovations,select alternative projects from the perspective of enterprise strategy.This paper primarily explores the use of project portfolio management in enterprise project management,hoping to improve the quality of enterprise project management and the utilization efficiency of project portfolio management in enterprise project management.
基金supported by Guangzhou Railway Polytechnic(No.GTXYRC 250107)Guangzhou Municipal Education Bureau(No.2025YBJG010).
文摘As the core carrier of Lingnan culture and a nationally famous historical&cultural city,Guangzhou preserves more than 3000 immovable historic buildings,including arcade rows,ancestral halls,Xiguan mansions and modern public edifices.Their brick-timber hybrid structures,high-density“bambootube”street pattern and hot-humid subtropical climate create unique fire challenges.This study systematically summarizes an“inherent-acquired-environmental”superimposed fire-risk mechanism.By integrating traditional Cantonese fire-resistance wisdom—such as Qingyun fire lanes,wok-ear gables and courtyard smoke vents—and heritage-friendly innovations,a three-level policy-technology-management protection framework is established.Hierarchical protection aligned with value grading,life-cycle technology pathways and multistakeholder collaboration is proposed.The“minimum-intervention and performance-based”route and the“regulation-guideline-standard”policy loop developed by Guangzhou reduce the fire incidence of priority historic buildings while retaining heritage authenticity,offering a replicable paradigm for balancing fire safety and conservation in hot-humid,high-density contexts.
