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.
作者机构：
[Zhang, Chipeng; Li, Wei; Zhou, Hui; Jiang, Dapeng; Bo, Guowei; Deng, Cuiling] Changsha Univ Sci & Technol, Coll Energy & Power Engn, Changsha 410114, Peoples R China.;[Bo, Guowei; Sun, Youping] Guangxi Univ Sci & Technol, Guangxi Key Lab Automobile Components & Vehicle Te, Liuzhou 545006, Peoples R China.;[Peng, ZR; Wang, Chenyang; Peng, Zirong; Bo, Guowei; Wang, CY] Tech Univ Munich, Chair Mat Engn Addit Mfg, Dept Mat Engn, Boltzmannstr 15, D-85748 Garching, Germany.;[Mao, Guoling] China North Engine Res Inst, Natl Key Lab Vehicle Power Syst, Tianjin 300400, Peoples R China.;[Jiang, Fulin] Hunan Univ, Coll Mat Sci & Engn, Changsha 410082, Peoples R China.
通讯机构：
[Mao, GL ] C;[Peng, ZR ; Wang, CY] T;Tech Univ Munich, Chair Mat Engn Addit Mfg, Dept Mat Engn, Boltzmannstr 15, D-85748 Garching, Germany.;China North Engine Res Inst, Natl Key Lab Vehicle Power Syst, Tianjin 300400, Peoples R China.
关键词：
Al-Si alloy;Microstructural classification;Automatic phase extraction;Unsupervised machine learing;Supervised deep learing
摘要：
Microstructural classification based on microscopic images are mostly done manually by human experts, which is time-consuming and generally leads to uncertainties due to subjectivity. In this work, machine learning and deep learning are used to automatically retrieve the useful morphology information of Si phase in Al-Si alloys which are widely used as various automotive components. Concretely, both clean mircographs without oxidization and noisy micrographs with oxidization are prepared under optical microscopy. Then an unsupervised machine learning algorithm (K-means clustering) is employed without manually labeled training data. The results show that a 92 % accuracy of extracting Si phase could be achieved on clean data, while only 75 % on noisy data. On the other hand, a supervised deep learning method (U-Net convolutional neural network) based on mixture of clean and noisy training dataset achieves high accuracy of recognizing Si phase in both clean (92 %) and noisy (87 %) micrographs. Meanwhile, the influence of the amount of training data and the proportion of the Si phase in training micrographs on the accuracy are also discussed. Further, when the training data used in U-Net method are labeled by K-means method instead of human efforts, U-Net method can achieve high accuracy in clean and noisy data.
Microstructural classification based on microscopic images are mostly done manually by human experts, which is time-consuming and generally leads to uncertainties due to subjectivity. In this work, machine learning and deep learning are used to automatically retrieve the useful morphology information of Si phase in Al-Si alloys which are widely used as various automotive components. Concretely, both clean mircographs without oxidization and noisy micrographs with oxidization are prepared under optical microscopy. Then an unsupervised machine learning algorithm (K-means clustering) is employed without manually labeled training data. The results show that a 92 % accuracy of extracting Si phase could be achieved on clean data, while only 75 % on noisy data. On the other hand, a supervised deep learning method (U-Net convolutional neural network) based on mixture of clean and noisy training dataset achieves high accuracy of recognizing Si phase in both clean (92 %) and noisy (87 %) micrographs. Meanwhile, the influence of the amount of training data and the proportion of the Si phase in training micrographs on the accuracy are also discussed. Further, when the training data used in U-Net method are labeled by K-means method instead of human efforts, U-Net method can achieve high accuracy in clean and noisy data.
作者机构：
[Gan, Lang; Han, Linhu; Peng, Yifan; Qiu, Wei; Jiang, Chenmeng; Gan, L] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Hunan, Peoples R China.;[Ren, YJ; Ren, Yanjie] Zhejiang Univ Sci & Technol, Sch Mech & Energy Engn, Hangzhou 310023, Zhejiang, Peoples R China.;[Zhao, Yuhang] Natl Energy Grp Shenhua Harwusu Open Pit, Recycling Econ Sci & Technol Innovat Ctr, Erdos 010300, Inner Mongolia, Peoples R China.
通讯机构：
[Ren, YJ ] Z;[Gan, L ] C;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Hunan, Peoples R China.;Zhejiang Univ Sci & Technol, Sch Mech & Energy Engn, Hangzhou 310023, Zhejiang, Peoples R China.
关键词：
PEMFCs;Bps;DC magnetron sputtering;Cr 2 AlC MAX phase;Corrosion behavior
摘要：
Developing highly effective anticorrosive coating for stainless steel bipolar plates is essential to proton exchange membrane fuel cells. In this work, Cr2AlC MAX phase coatings are deposited on SS304 substrates using direct current magnetron sputtering technology with various substrate temperatures. The optimized coating deposited at 600 °C exhibits superior corrosion resistance, with a corrosion current density (Icorr) of 1.45 × 10−8 A·cm−2 and an interface contact resistance (ICR) of 9.04 mΩ cm−2. Additionally, the Cr2AlC-600 °C exhibits the largest Rct value after 500 h of immersion in the electrolyte, a value four orders of magnitude higher than that of SS304, highlighting the remarkable commercial application of the novel coating.
Developing highly effective anticorrosive coating for stainless steel bipolar plates is essential to proton exchange membrane fuel cells. In this work, Cr2AlC MAX phase coatings are deposited on SS304 substrates using direct current magnetron sputtering technology with various substrate temperatures. The optimized coating deposited at 600 °C exhibits superior corrosion resistance, with a corrosion current density (Icorr) of 1.45 × 10−8 A·cm−2 and an interface contact resistance (ICR) of 9.04 mΩ cm−2. Additionally, the Cr2AlC-600 °C exhibits the largest Rct value after 500 h of immersion in the electrolyte, a value four orders of magnitude higher than that of SS304, highlighting the remarkable commercial application of the novel coating.
摘要：
SiO2 soot preform sintering is a critical step in the indirect chemical vapor deposition (CVD) method for synthesizing high-quality silica glass, which involves hydroxyl (OH) decomposition, heat and mass transfer, as well as densification. These phenomena are not fully coupled in the traditional models, which leads to inaccurate numerical predictions. To address this, a porous media model with multiphase transport and solid mechanics bidirectional coupling (MTM) is proposed for the soot preform sintering process in this paper. The model is validated by experimental results. Using this model, the densification behavior of soot preform during sintering process is predicted, and the effects of densification on heat and mass transfer are thoroughly examined. The OH decomposition rate and gas phase transport are intensified in the later sintering stage when densification occurs significantly. Consequently, the OH is concentrated, presenting a ringed-shape distribution. The temperature distribution is also affected, which transforms from a layered shape to a ringed shape, with the maximum temperature decreasing by approximately 20 °C. Furthermore, the effects of the temperature rise curve are explored. It is found that a higher preheating temperature and a longer holding time are preferable for the synthesis of high-quality silica glass.
SiO2 soot preform sintering is a critical step in the indirect chemical vapor deposition (CVD) method for synthesizing high-quality silica glass, which involves hydroxyl (OH) decomposition, heat and mass transfer, as well as densification. These phenomena are not fully coupled in the traditional models, which leads to inaccurate numerical predictions. To address this, a porous media model with multiphase transport and solid mechanics bidirectional coupling (MTM) is proposed for the soot preform sintering process in this paper. The model is validated by experimental results. Using this model, the densification behavior of soot preform during sintering process is predicted, and the effects of densification on heat and mass transfer are thoroughly examined. The OH decomposition rate and gas phase transport are intensified in the later sintering stage when densification occurs significantly. Consequently, the OH is concentrated, presenting a ringed-shape distribution. The temperature distribution is also affected, which transforms from a layered shape to a ringed shape, with the maximum temperature decreasing by approximately 20 °C. Furthermore, the effects of the temperature rise curve are explored. It is found that a higher preheating temperature and a longer holding time are preferable for the synthesis of high-quality silica glass.
关键词：
bionic amphibious robot;composite drive;motion control;track mechanism;undulating fin
摘要：
Amphibious robots offer promising applications in field scenarios such as search and rescue, exploration and reconnaissance, and environment monitoring. However, achieving high locomotion performance in terrestrial, aquatic, and soft muddy transition areas remains challenging. This study presents a novel amphibious robot based on the hybrid drive of tracks and bionic fins. The robot is driven by a pair of tracks on land and by a pair of undulating fins underwater, without the need for switching operating modes due to the simultaneous drive of the two components. The structure design is introduced and the united operating strategies are derived for propulsion in multiple environments propulsion. A land-water united controller for the heading angle and track/fin frequency is designed based on a mathematical model. In field experiments, the robot achieved the maximum linear velocities of 2 m/s on land and 0.51 m/s underwater, with maximum yaw rates of 225 / degrees s ${}<^>{\circ }/{\rm{s}}$ and 100 / degrees s ${}<^>{\circ }/{\rm{s}}$, respectively. The robot could transition seamlessly between land and water in less than 2 s. The closed-loop control experiments demonstrated that the robot could quickly follow the desired angle with minimal error in both media using the same controller and parameters. The proposed simultaneous drive method enhances the multi-terrain motion capacity and cross-medium performance while reducing control complexity of amphibious robot, providing a new perspective for the development of self-adaptive and high-performance amphibious robots for practical application.
摘要：
A new method was proposed for predicting residual stress in light alloys using truncated conical indentation. In this method, a truncated conical indenter with a cone angle of 120°, insensitive to edge-chamfer and friction effects, was used to test the residual stress of light alloys. Selecting the ratio of indentation work between stressed and unstressed specimens as an analytical parameter, a dimensionless truncated conical indentation (TCI) model related to the ratio of indentation work between stressed and unstressed, material properties, and normalized residual stress was established via dimensional analysis and numerical calculations. The TCI model could predict equi-biaxial residual stress and uniaxial residual stress, and its accuracy was verified in a wide range of light alloys with varying residual stress by numerical simulation. The stability of the TCI model is verified numerically by introducing errors in material parameters. Truncated conical indentation tests were conducted on cruciform specimens and rectangular specimens respectively made of three aluminum alloys. The results exhibited the residual stress predicted by proposed method agrees well with the applied stress, and the relative errors between them were within ±10 % in most cases.
A new method was proposed for predicting residual stress in light alloys using truncated conical indentation. In this method, a truncated conical indenter with a cone angle of 120°, insensitive to edge-chamfer and friction effects, was used to test the residual stress of light alloys. Selecting the ratio of indentation work between stressed and unstressed specimens as an analytical parameter, a dimensionless truncated conical indentation (TCI) model related to the ratio of indentation work between stressed and unstressed, material properties, and normalized residual stress was established via dimensional analysis and numerical calculations. The TCI model could predict equi-biaxial residual stress and uniaxial residual stress, and its accuracy was verified in a wide range of light alloys with varying residual stress by numerical simulation. The stability of the TCI model is verified numerically by introducing errors in material parameters. Truncated conical indentation tests were conducted on cruciform specimens and rectangular specimens respectively made of three aluminum alloys. The results exhibited the residual stress predicted by proposed method agrees well with the applied stress, and the relative errors between them were within ±10 % in most cases.
期刊：
Thermal Science and Engineering Progress,2025年:103665 ISSN：2451-9049
通讯作者：
Jing Zhao
作者机构：
[Xinxuan Cheng; Zixun Zhong; Yongkang Ma; Caiting Zhou] College of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114 Hunan, China;State Key Laboratory of Disaster Prevention and Reduction for Power Grid, Changsha University of Science and Technology, Changsha 410114 Hunan, China;[Jing Zhao] College of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114 Hunan, China<&wdkj&>State Key Laboratory of Disaster Prevention and Reduction for Power Grid, Changsha University of Science and Technology, Changsha 410114 Hunan, China
通讯机构：
[Jing Zhao] C;College of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114 Hunan, China<&wdkj&>State Key Laboratory of Disaster Prevention and Reduction for Power Grid, Changsha University of Science and Technology, Changsha 410114 Hunan, China
摘要：
Proton exchange membrane fuel cells are promising for clean energy applications, but thermal management remains a critical challenge. This study experimentally investigated the temperature distribution and evolution of an air-cooled proton exchange membrane fuel cell stack under various dynamic operating conditions. Using 60 thermocouples inserted into the cathode channels, the formation, development, and propagation of high-temperature regions were thoroughly studied. The research results indicated that temperature distribution became increasingly non-uniform with rising current density, particularly under overload conditions. Hot spots first appeared near the hydrogen inlet and air outlet, expanding to central regions as current density increased. Overload operation led to rapid temperature rises and the formation of thermal bridges between hot spots, highlighting the risks of thermal instability. Moreover, the study established a connection between temperature variations and water management problems. Anode flooding intensified heat generation and led to voltage fluctuations. In addition, it was found that the maximum temperature difference could serve as a sensitive indicator for detecting water flooding inside fuel cells. The results of this study are helpful for a better understanding of the internal thermal behavior of air-cooled proton exchange membrane fuel cells and are of great significance for optimizing their thermal management strategies.
Proton exchange membrane fuel cells are promising for clean energy applications, but thermal management remains a critical challenge. This study experimentally investigated the temperature distribution and evolution of an air-cooled proton exchange membrane fuel cell stack under various dynamic operating conditions. Using 60 thermocouples inserted into the cathode channels, the formation, development, and propagation of high-temperature regions were thoroughly studied. The research results indicated that temperature distribution became increasingly non-uniform with rising current density, particularly under overload conditions. Hot spots first appeared near the hydrogen inlet and air outlet, expanding to central regions as current density increased. Overload operation led to rapid temperature rises and the formation of thermal bridges between hot spots, highlighting the risks of thermal instability. Moreover, the study established a connection between temperature variations and water management problems. Anode flooding intensified heat generation and led to voltage fluctuations. In addition, it was found that the maximum temperature difference could serve as a sensitive indicator for detecting water flooding inside fuel cells. The results of this study are helpful for a better understanding of the internal thermal behavior of air-cooled proton exchange membrane fuel cells and are of great significance for optimizing their thermal management strategies.
通讯机构：
[Jiang, FL; Zhang, H ] H;[Li, W ] C;Changsha Univ Sci & Technol, Coll Energy & Power Engn, Changsha 410114, Peoples R China.;Hunan Univ, Coll Mat Sci & Engn, Changsha 410082, Peoples R China.
关键词：
Al-Cu-Mg alloys;Multi-stage hot deformation;Warm deformation;Dynamic softening and hardening;Static softening and hardening;Pre-precipitation microstructure
摘要：
Complex dynamic and static softening behaviors in flow stress evolutions serve as important indicator for optimizing the power or load required by thermomechanical processes of Al-Cu-Mg alloys. However, the flow stress behaviors during the commonly employed industrial multi-stage warm and hot forming of Al-Cu-Mg alloys are rarely reported. In this work, therefore, the complicated flow hardening or softening mechanisms during multi-stage warm (200 ºC) and hot (300 ºC and 400 ºC) deformation of the air-cooled (AC) and water-quenched (WQ) Al-Cu-Mg-Zr alloy after solution treatment were studied by means of isothermal (1, 2, 3, 6 passes) compression tests, microstructural characterization and in-situ electrical resistivity monitoring. During warm deformation at 200 ºC, clear flow hardening was presented until high strain level (0.8–1.0) for AC and WQ alloy, after which slight flow softening and hardening was observed due to the dynamic recovery caused by high strain energy, respectively. But the more the number of deformation pass, the stronger static hardening caused by static precipitation, leading to higher flow stress and enhancing the flow softening behaviors within high strain range (0.8–1.2). During hot deformation at 300 ºC and 400 ºC, the clear dynamic and static softening of AC and WQ alloy are mainly attributed to dynamic/static recovery (DRV and SRV) and precipitation, respectively. However, the strain energy consumed by static recovery and/or precipitation would increase significantly with rising number of static holding process. Consequently, the stored strain energy for the occurrence of DRV during later stage of deformation ( ε >0.8) was insufficient, leading to flow hardening of 3- and 6-pass deformation.
Complex dynamic and static softening behaviors in flow stress evolutions serve as important indicator for optimizing the power or load required by thermomechanical processes of Al-Cu-Mg alloys. However, the flow stress behaviors during the commonly employed industrial multi-stage warm and hot forming of Al-Cu-Mg alloys are rarely reported. In this work, therefore, the complicated flow hardening or softening mechanisms during multi-stage warm (200 ºC) and hot (300 ºC and 400 ºC) deformation of the air-cooled (AC) and water-quenched (WQ) Al-Cu-Mg-Zr alloy after solution treatment were studied by means of isothermal (1, 2, 3, 6 passes) compression tests, microstructural characterization and in-situ electrical resistivity monitoring. During warm deformation at 200 ºC, clear flow hardening was presented until high strain level (0.8–1.0) for AC and WQ alloy, after which slight flow softening and hardening was observed due to the dynamic recovery caused by high strain energy, respectively. But the more the number of deformation pass, the stronger static hardening caused by static precipitation, leading to higher flow stress and enhancing the flow softening behaviors within high strain range (0.8–1.2). During hot deformation at 300 ºC and 400 ºC, the clear dynamic and static softening of AC and WQ alloy are mainly attributed to dynamic/static recovery (DRV and SRV) and precipitation, respectively. However, the strain energy consumed by static recovery and/or precipitation would increase significantly with rising number of static holding process. Consequently, the stored strain energy for the occurrence of DRV during later stage of deformation ( ε >0.8) was insufficient, leading to flow hardening of 3- and 6-pass deformation.
摘要：
Condensation assessment of a residential building in Changsha, China-located in the hot summer and cold winter climate zone-was conducted during the Plum Rain Season (PRS) using Energy Plus simulations and field measurements. Window-opening behaviour significantly influences indoor air quality and thermal comfort. This study specifically examines how window-opening patterns, including opening duration and opening degree, affect interior surface condensation risk in a rural residential building during PRS. Results indicate that window operational status (open/closed) exerts a dominant influence on condensation risk, while varying window opening degrees during identical opening duration showed negligible differential impacts. Critical temporal patterns emerged: morning window openings during PRS should be avoided, whereas afternoon (15:00-18:00) and nighttime (18:00-06:00) ventilation proves advantageous. Optimisation analysis revealed that implementing combined afternoon and nighttime ventilation windows (15:00-18:00 + 18:00-06:00) achieved the lowest condensation risk of 0.112 among evaluated scenarios. Furthermore, monthly-adjusted window operation strategies yielded eight recommended ventilation modes, maintaining condensation risks below 0.11 and providing occupant-tailored solutions for Changsha's PRS conditions. These findings establish evidence-based guidelines for moisture control through optimised window operation in climate-responsive building management.
作者机构：
[Dongying Dong; Kun Chen; Linjun Zeng] College of Energy and Power Engineering, Changsha University of Science & Technology, Changsha, 410114, China;[Jianing Zhang; Zhoucheng Wu] International College of Engineering, Changsha University of Science & Technology, Changsha, 410114, China;[Xu Zhang] College of Automotive and Mechanical Engineering, Changsha University of Science & Technology, Changsha, 410114, China;[Junjia Cui] State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, 410082, China
通讯机构：
[Linjun Zeng] C;College of Energy and Power Engineering, Changsha University of Science & Technology, Changsha, 410114, China
摘要：
TC4 based composites were facing an urgent need to enhance physical performance. In this work, electromagnetic powder compaction (EMPC) technology was used to prepare carbon nanotubes reinforced TC4 based (CNTs/TC4) composites. The micro morphology and properties of the sintered bodies were studied through scanning/transmission electron microscopy (SEM/TEM) and a universal material testing machine at different sintering temperatures. Results showed that there was a significant turning point at 1100 °C, with a relative density of 98.01%. The relationship between the relative length and density of sintered bodies was established through Gaussian fitting. The CNTs partially reacted with the TC4 matrix after 700 °C, generating equiaxed TiC particles. The compressive strength and strain reached the maximum values at 1300 °C and 600 °C, respectively, with values of 1884.64 MPa and 0.2336. The enhancement factors for compressive strength were only alloying and TiC particles at 1100 °C. There was not much difference in the fusion effect of particles at 1100 °C and 1300 °C. From the above analysis, it can be concluded that the CNTs/TC4 composites prepared by EMPC had relatively good comprehensive mechanical properties when sintered at 1100 °C.
TC4 based composites were facing an urgent need to enhance physical performance. In this work, electromagnetic powder compaction (EMPC) technology was used to prepare carbon nanotubes reinforced TC4 based (CNTs/TC4) composites. The micro morphology and properties of the sintered bodies were studied through scanning/transmission electron microscopy (SEM/TEM) and a universal material testing machine at different sintering temperatures. Results showed that there was a significant turning point at 1100 °C, with a relative density of 98.01%. The relationship between the relative length and density of sintered bodies was established through Gaussian fitting. The CNTs partially reacted with the TC4 matrix after 700 °C, generating equiaxed TiC particles. The compressive strength and strain reached the maximum values at 1300 °C and 600 °C, respectively, with values of 1884.64 MPa and 0.2336. The enhancement factors for compressive strength were only alloying and TiC particles at 1100 °C. There was not much difference in the fusion effect of particles at 1100 °C and 1300 °C. From the above analysis, it can be concluded that the CNTs/TC4 composites prepared by EMPC had relatively good comprehensive mechanical properties when sintered at 1100 °C.
摘要：
Co-combustion of coal gangue (CG) and biowaste, such as wheat straw (WS), offers a sustainable approach to waste valorization and emissions reduction. However, the combustion characteristics of CG in the presence of WS have been insufficiently explored. This study investigates the co-combustion behavior of CG, WS, and their mixtures at five different ratios using a thermogravimetric analyzer (TGA). The results reveal that the addition of WS significantly lowers both the ignition and burnout temperatures of CG. Pure CG exhibits ignition and burnout temperatures of 474.4 degrees C and 770.2 degrees C, respectively, while CG/WS blends show reduced temperatures of 255.6-267.9 degrees C for ignition and 608.9-710.5 degrees C for burnout. A pronounced synergistic interaction occurs mainly between 200 and 600 degrees C during the co-combustion process. Kinetic analysis demonstrates that WS addition substantially decreases the apparent activation energy of the blends, from 75.41 kJ mol-1 for CG to 34.14 kJ mol-1 for the blend with 20% WS. The findings such as the reduced ignition and burnout temperatures, and lower activation energy indicate that CG/WS co-combustion can significantly improve combustion behaviors. Hence, this study provides valuable insights into the thermochemical behavior and kinetics of CG/WS co-firing, promoting the optimal utilization of biomass-coal waste for efficient energy production in industrial applications while offering waste-to-energy solutions.
摘要：
The global shortage of fresh-water resources is becoming increasingly serious, while the photothermal evaporation has a broad application in the desalination of seawater. However, the physical modeling for photothermal evaporation is not perfect enough to support further improvement of the evaporation performance of photothermal materials. In this study, a photothermal evaporation model using Ti 3 C 2 -wood as a photothermal material is established. The impact of various external environmental factors, including light intensity, initial ambient temperature and air humidity, on the evaporation performance of photothermal materials has been investigated. Additionally, an internal relationship is created between the photothermal material's evaporation behavior and its physical properties, such as thermal conductivity, surface absorbance, and material thickness. On the basis of analytical research, some conclusions have been demonstrated that the evaporative properties of photothermal materials are positively correlated with light intensity and initial ambient temperature, but opposite to air humidity. Besides, the evaporation performance of photothermal materials is generally enhanced by increases in thermal conductivity, surface absorbance and material thickness. Moreover, it should be pointed out that the numerical analysis indicates if the photothermal material's thickness goes above a particular range, it may lead to insufficient water supply, thereby suppressing the evaporation rate conversely. This work can provide theoretical guidance for exploring the methods to enhance the photothermal material's evaporation performance, which is of great significance to solve the increasingly serious problem of the lack of fresh-water resources.
The global shortage of fresh-water resources is becoming increasingly serious, while the photothermal evaporation has a broad application in the desalination of seawater. However, the physical modeling for photothermal evaporation is not perfect enough to support further improvement of the evaporation performance of photothermal materials. In this study, a photothermal evaporation model using Ti 3 C 2 -wood as a photothermal material is established. The impact of various external environmental factors, including light intensity, initial ambient temperature and air humidity, on the evaporation performance of photothermal materials has been investigated. Additionally, an internal relationship is created between the photothermal material's evaporation behavior and its physical properties, such as thermal conductivity, surface absorbance, and material thickness. On the basis of analytical research, some conclusions have been demonstrated that the evaporative properties of photothermal materials are positively correlated with light intensity and initial ambient temperature, but opposite to air humidity. Besides, the evaporation performance of photothermal materials is generally enhanced by increases in thermal conductivity, surface absorbance and material thickness. Moreover, it should be pointed out that the numerical analysis indicates if the photothermal material's thickness goes above a particular range, it may lead to insufficient water supply, thereby suppressing the evaporation rate conversely. This work can provide theoretical guidance for exploring the methods to enhance the photothermal material's evaporation performance, which is of great significance to solve the increasingly serious problem of the lack of fresh-water resources.
期刊：
Chemical Engineering Journal,2025年511:162058 ISSN：1385-8947
通讯作者：
Zou, Liangyu;Jia, CK;Liang, ZW
作者机构：
[Zou, Liangyu; Jia, CK; Jia, Chuankun; Huang, Yunkun; Xiao, Junbing] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Dept Energy Storage Sci & Engn, Changsha 410114, Hunan, Peoples R China.;[Huang, Yangqiang; Liang, Zhiwu] Hunan Univ, Coll Chem & Chem Engn, Joint Int Ctr CO2 Capture & Storage iCCS, Prov Hunan Key Lab Cost Effect Utilizat Fossil Fue, Changsha 410082, Hunan, Peoples R China.
通讯机构：
[Zou, LY; Jia, CK ] C;[Liang, ZW ] H;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Dept Energy Storage Sci & Engn, Changsha 410114, Hunan, Peoples R China.;Hunan Univ, Coll Chem & Chem Engn, Joint Int Ctr CO2 Capture & Storage iCCS, Prov Hunan Key Lab Cost Effect Utilizat Fossil Fue, Changsha 410082, Hunan, Peoples R China.
关键词：
Di-n-butylamine;Fomic acid dehydrogenation;Absorption/desorption rate;CO2 capture;Cyclic CO2 capacity
摘要：
Background Secondary amines with strong alkalinity can be used as additives in the field of formic acid hydrogen production. The novel absorbent system combing secondary amine and tertiary amine is prosperous in industrial application of CO 2 capture.
Secondary amines with strong alkalinity can be used as additives in the field of formic acid hydrogen production. The novel absorbent system combing secondary amine and tertiary amine is prosperous in industrial application of CO 2 capture.
Results As an additive of formic acid dehydrogenation system with Pd/C catalyst, the promoting effect of di-n-butylamine (DBA) can be achieved over 40% ahead of the peer additives. Screening test of hybrid solutions composed of additive amine, DBA, and H 2 O were comprehensively investigated using the rapid solvent screening apparatus and VLE apparatus. The combination of DBA and N,N-dimethyl ethanolamine (DMEA) achieved the higher rich loading, strong cyclic CO 2 capacity and stripping rate over a wide range of CO 2 loading. Also, the absorption of high content CO 2 into the hybrid DBA/DMEA solution was investigated in a lab-scale simulated absorption device. The effects of operating parameters (CO 2 loading, solvent concentration and liquid temperature (T), etc.) on the CO 2 absorption were evaluated in terms of CO 2 removal rate ( θ CO2 ). Furthermore, a predicted model of θ CO2 , which could be suitable for different solution systems with generated gas treatment of FA dehydrogenation, was also proposed and developed using semi-empirical models as function of operating parameters in this work.
As an additive of formic acid dehydrogenation system with Pd/C catalyst, the promoting effect of di-n-butylamine (DBA) can be achieved over 40% ahead of the peer additives. Screening test of hybrid solutions composed of additive amine, DBA, and H 2 O were comprehensively investigated using the rapid solvent screening apparatus and VLE apparatus. The combination of DBA and N,N-dimethyl ethanolamine (DMEA) achieved the higher rich loading, strong cyclic CO 2 capacity and stripping rate over a wide range of CO 2 loading. Also, the absorption of high content CO 2 into the hybrid DBA/DMEA solution was investigated in a lab-scale simulated absorption device. The effects of operating parameters (CO 2 loading, solvent concentration and liquid temperature (T), etc.) on the CO 2 absorption were evaluated in terms of CO 2 removal rate ( θ CO2 ). Furthermore, a predicted model of θ CO2 , which could be suitable for different solution systems with generated gas treatment of FA dehydrogenation, was also proposed and developed using semi-empirical models as function of operating parameters in this work.
通讯机构：
[Huang, JC; Peng, ZY ] C;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Key Lab Efficient & Clean Energy Utilizat, Changsha 410111, Peoples R China.
摘要：
Despite the advancements in film fabrication techniques for emerging perovskite solar cells, achieving a high-quality film by solution processing, while maintaining considerable performance remains a significant challenge. To tackle the issue of inferior CsPbI 2 Br perovskite films deposited via solution-based methods, a novel thermal conduction heating approach was devised and implemented, significantly enhancing film uniformity. Crucially, aliphatic amine acetates (3A) were introduced into the precursor solution to regulate the crystallization process and therefore to mitigate defects. Systematic investigation into the impact of 3A molecules featuring varying alkyl chain lengths on defect passivation revealed that the molecular dipole moment of these additives contributed to both defect mitigation and grain size refinement. Notably, the integration of alkyl chains significantly bolstered the hydrophobic properties of the perovskite film. Consequently, an impressive efficiency of 13.50% for HTM-free carbon-based CsPbI 2 Br perovskite solar cells was achieved, and the device exhibited robust stability retaining 92.4% of its initial efficiency at room temperature after being stored in dry air for 5400 h. This research offers profound insights into defect passivation mechanisms and perovskite crystallization dynamics, paving the way for further advancements in the field of perovskite solar cell technology.
作者机构：
[Li, Xinzhuo; Tian, Hong; Sun, Liutao; Dai, Pengfei; Xu, Chenghui; Huang, Zhangjun; Li, XZ] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Peoples R China.
通讯机构：
[Li, XZ ] C;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha 410114, Peoples R China.
关键词：
Ammonia/methane mixture combustion;Mechanism reduction;Mechanism optimization;Artificial Neural Network;NO x emissions
摘要：
The application of ammonia/methane (NH 3 /CH 4 ) blended fuels in gas turbines has received considerable attention, and the development of their combustors requires the implementation of more precise and compact reaction mechanisms. In this work, we propose a new optimization mechanism for ammonia/methane and comprehensively verify the performance of the optimization mechanism. A detailed chemical mechanism with 65 species and 466 reactions (Detailed-Mech) was first assembled using models from the literature. A directed relation graph with error propagation (DRGEP) and computational singular perturbation (CSP) method were then used to obtain a 23-species, 73-reaction compact reaction model (Reduced-Mech). Finally, the pre-exponential factor ( A ) and activation energy ( E a ) of five significant elementary reactions were optimized using an Artificial Neural Network (ANN) to obtain the optimized mechanism (ANN-Mech). The ANN-Mech was validated at ignition delay times (IDT), laminar burning velocity (LBV), plug flow reactor (PFR) species distribution, and in the 3-D combustion chamber. The study found that the logarithmic mean errors of IDT decreased by 3.9 %. The mean error of laminar burning velocity is reduced from 18.5 % to 9.5 %, and the prediction error of NO X in ANN-Mech is reduced by 47.5 %. The results of the premixed flames simulation indicate that the temperature and velocity fields of ANN-Mech at different ammonia fractions better agree with the Detailed-Mech. Additionally, the NO error of the outlet was reduced by 30 %. The calculation speed was also increased by ten times compared to the Detailed-Mech.
The application of ammonia/methane (NH 3 /CH 4 ) blended fuels in gas turbines has received considerable attention, and the development of their combustors requires the implementation of more precise and compact reaction mechanisms. In this work, we propose a new optimization mechanism for ammonia/methane and comprehensively verify the performance of the optimization mechanism. A detailed chemical mechanism with 65 species and 466 reactions (Detailed-Mech) was first assembled using models from the literature. A directed relation graph with error propagation (DRGEP) and computational singular perturbation (CSP) method were then used to obtain a 23-species, 73-reaction compact reaction model (Reduced-Mech). Finally, the pre-exponential factor ( A ) and activation energy ( E a ) of five significant elementary reactions were optimized using an Artificial Neural Network (ANN) to obtain the optimized mechanism (ANN-Mech). The ANN-Mech was validated at ignition delay times (IDT), laminar burning velocity (LBV), plug flow reactor (PFR) species distribution, and in the 3-D combustion chamber. The study found that the logarithmic mean errors of IDT decreased by 3.9 %. The mean error of laminar burning velocity is reduced from 18.5 % to 9.5 %, and the prediction error of NO X in ANN-Mech is reduced by 47.5 %. The results of the premixed flames simulation indicate that the temperature and velocity fields of ANN-Mech at different ammonia fractions better agree with the Detailed-Mech. Additionally, the NO error of the outlet was reduced by 30 %. The calculation speed was also increased by ten times compared to the Detailed-Mech.
摘要：
Amorphous carbon, particularly hard carbon (HC), is widely considered as the most promising anode material for sodium-ion batteries (SIBs) due to its high reversible capacity and cost-effectiveness. However, the complex and poorly defined structural properties of HC present challenges in understanding the underlying sodium storage mechanisms. To facilitate the rational design of high-performance HC anodes, a comprehensive understanding of the correlation between microstructure and sodium storage behavior is critical. This Review critically examines the interplay between the structural features of HC and its sodium storage capabilities, focusing on two key factors: pore structure and surface functional groups. It begins by outlining the fundamental sodium storage mechanisms in HC, followed by an in-depth discussion of how pore structure and surface chemistry influence sodium-ion storage. Finally, strategic insights are provided on how to manipulate these structural factors to optimize sodium storage performance. This Review aims to drive the development of next-generation high-performance HC anodes and support the commercialization of SIBs.
作者机构：
[Liu, Rui; Zhang, Chuanliang; Chen, Jiaxiang; Wang, Ziyi] Changsha Univ Sci & Technol, Coll Energy & Power Engn, Changsha 410114, Peoples R China.;[Zhao, Bin] Changsha Univ Sci & Technol, Sch Elect & Informat Engn, Changsha 410114, Peoples R China.
通讯机构：
[Zhao, B ] C;Changsha Univ Sci & Technol, Sch Elect & Informat Engn, Changsha 410114, Peoples R China.
关键词：
Airfoil fin PCHE;Bezier curves;Pareto front;Multi-objective genetic algorithm;Comprehensive performance
摘要：
The airfoil fin (AFF) Printed circuit heat exchanger (PCHE) has attracted significant attention for its excellent comprehensive performance. This study proposes an optimized design for AFF PCHE to enhance the comprehensive performance by integrating Bézier curves, computational fluid dynamics (CFD), and multi-objective genetic algorithm (MOGA). A set of 12 Bézier curve-based variables is utilized to define and control the airfoil geometry, with optimization targets set on two comprehensive evaluation criteria: the first enhanced ratio (η1) and the third enhanced ratio (η3). The MOGA-generated Pareto front reveals the evolution of AFF structures in relation to η1 and η3. Results show that as the leading and trailing edges of the AFFs become sharper and the thickness decreases, the η1 of the PCHE channel gradually increases, while η3 decreases. Conversely, as the thickness of the AFFs increases and the trailing edge shape transitions from blunt to elliptical and finally to round, η3 significantly increases while η1 decreases. Furthermore, when changes focus mainly on the leading edge of the AFFs, η3 improves without markedly affecting η1. Compared to the traditional airfoil channel, the η1 of the Fin-b channel increases by 3.1%-10.8%, demonstrating its greater suitability under identical flow rate conditions. Similarly, the η3 of the Fin-g channel is 1.4%-11.6% higher than that of the traditional airfoil channel, highlighting its superior performance under identical pumping power conditions. The present work provides a valuable reference for optimizing the design of AFF PCHEs under identical flow rate and pumping power conditions.
The airfoil fin (AFF) Printed circuit heat exchanger (PCHE) has attracted significant attention for its excellent comprehensive performance. This study proposes an optimized design for AFF PCHE to enhance the comprehensive performance by integrating Bézier curves, computational fluid dynamics (CFD), and multi-objective genetic algorithm (MOGA). A set of 12 Bézier curve-based variables is utilized to define and control the airfoil geometry, with optimization targets set on two comprehensive evaluation criteria: the first enhanced ratio (η1) and the third enhanced ratio (η3). The MOGA-generated Pareto front reveals the evolution of AFF structures in relation to η1 and η3. Results show that as the leading and trailing edges of the AFFs become sharper and the thickness decreases, the η1 of the PCHE channel gradually increases, while η3 decreases. Conversely, as the thickness of the AFFs increases and the trailing edge shape transitions from blunt to elliptical and finally to round, η3 significantly increases while η1 decreases. Furthermore, when changes focus mainly on the leading edge of the AFFs, η3 improves without markedly affecting η1. Compared to the traditional airfoil channel, the η1 of the Fin-b channel increases by 3.1%-10.8%, demonstrating its greater suitability under identical flow rate conditions. Similarly, the η3 of the Fin-g channel is 1.4%-11.6% higher than that of the traditional airfoil channel, highlighting its superior performance under identical pumping power conditions. The present work provides a valuable reference for optimizing the design of AFF PCHEs under identical flow rate and pumping power conditions.
摘要：
The flight mission of aeroengines exhibits dynamic features during operation. It is crucial to consider the effect of abrupt loading conditions when evaluating the creep behavior of turbine blades. In this paper, the effect of variable temperature and stress on creep rupture behavior of Ni-based single crystal (SX) turbine blade simulator specimen was systematically studied by experimental and finite element analysis methods. The experimental results indicated that creep strain jump could be observed with increasing temperature and stress, accompanied by the new primary and secondary stages. The creep fracture mechanism and microstructure evolution were revealed by the macro and micro analysis of the specimen after failure. Based on the above research, the creep damage model considering the material degradation and voids damage was used to calculate and analyze the creep behavior of the blade-like specimen. The finite element simulation results are nearly consistent with the experimental fracture path of the specimen.
The flight mission of aeroengines exhibits dynamic features during operation. It is crucial to consider the effect of abrupt loading conditions when evaluating the creep behavior of turbine blades. In this paper, the effect of variable temperature and stress on creep rupture behavior of Ni-based single crystal (SX) turbine blade simulator specimen was systematically studied by experimental and finite element analysis methods. The experimental results indicated that creep strain jump could be observed with increasing temperature and stress, accompanied by the new primary and secondary stages. The creep fracture mechanism and microstructure evolution were revealed by the macro and micro analysis of the specimen after failure. Based on the above research, the creep damage model considering the material degradation and voids damage was used to calculate and analyze the creep behavior of the blade-like specimen. The finite element simulation results are nearly consistent with the experimental fracture path of the specimen.
作者机构：
[Jia, CK; Xu, Zhizhao; Jia, Chuankun; Ding, Mei; Wang, Junqiang; Lu, Bo] Changsha Univ Sci & Technol, Inst Energy Storage Technol, Coll Energy & Power Engn, Changsha 410114, Peoples R China.;[Zhou, Guangmin; Liu, Zhexuan; Zhou, GM] Tsinghua Univ, Tsinghua Shenzhen Int Grad Sch, Shenzhen 518055, Peoples R China.
通讯机构：
[Jia, CK ; Ding, M] C;[Zhou, GM ] T;Changsha Univ Sci & Technol, Inst Energy Storage Technol, Coll Energy & Power Engn, Changsha 410114, Peoples R China.;Tsinghua Univ, Tsinghua Shenzhen Int Grad Sch, Shenzhen 518055, Peoples R China.
摘要：
The scarcity of lithium resources and the increasing volume of spent lithium-ion batteries (LIBs) exacerbate the imbalance between lithium supply and demand. The development of efficient recovery strategies of valuable lithium ion (Li(+)) from spent LIBs and their subsequent utilization presents both significant opportunities and challenges. Here, we propose an innovative approach for Li(+) recovery from spent lithium iron phosphate (LiFePO(4)) batteries (LFPs) and its subsequent utilization in alkaline zinc-ferricyanide flow batteries (AZFFBs). Utilizing a redox-mediated reaction, we achieve exceptional Li(+) recovery efficiency from spent LFPs. Furthermore, the recovered Li(+) in solution leads to the elevated ionic strength in the electrolyte, enhancing the concentration of [Fe(CN)(6)](4-) to a remarkable level of 1.74M. Utilizing the above catholyte, an AZFFB cell demonstrates the cycling life extending to 11000 cycles with a degradation rate as low as 0.00019% per cycle and 0.09% per day at a current density of 120mA cm(-2). This study introduces a straightforward and efficient protocol that eliminates additional intermediate processes, achieving effective Li(+) recovery from spent LFPs and subsequent utilization in flow batteries. The resulting AZFFB exhibits high energy density and long lifespan, positioning it as a promising candidate for large-scale energy storage solutions.
摘要：
In microscale structures, thermal and viscous effects are important factors affecting the effective transmission of acoustic energy. In this paper, the effects of porosity, single thermal effect, single viscous effect, and thermoviscous coupling on the acoustic energy transmission characteristics of microcolumn arrays are analyzed in detail by numerical solution of thermoviscous acoustic equations. The effects of temperature on thermal effect and viscous effects are discussed. The results show that the nonlinear coupling effect of thermal and viscous effects contributes the most to acoustic energy dissipation, and the viscous effect is much greater than that of the thermal effect. Compared with the case without thermoviscous dissipation, when a frequency of 7000 Hz sound wave propagates in a microcolumn array with a porosity of 0.5, the thermal viscous coupling effect, single viscous effect, and single thermal effect respectively reduce the sound transmission coefficient by about 33 %, 27.25 %, and 8.44 %. The transmission coefficient of acoustic energy decreases with the decrease of microcolumn array porosity. With the increase in temperature, the acoustic energy transmission loss curve shifts to high frequency, which is conducive to weakening the influence of the viscous dissipation effect on acoustic energy loss. The results are significant for understanding the sound transmission mechanism in microstructures.
In microscale structures, thermal and viscous effects are important factors affecting the effective transmission of acoustic energy. In this paper, the effects of porosity, single thermal effect, single viscous effect, and thermoviscous coupling on the acoustic energy transmission characteristics of microcolumn arrays are analyzed in detail by numerical solution of thermoviscous acoustic equations. The effects of temperature on thermal effect and viscous effects are discussed. The results show that the nonlinear coupling effect of thermal and viscous effects contributes the most to acoustic energy dissipation, and the viscous effect is much greater than that of the thermal effect. Compared with the case without thermoviscous dissipation, when a frequency of 7000 Hz sound wave propagates in a microcolumn array with a porosity of 0.5, the thermal viscous coupling effect, single viscous effect, and single thermal effect respectively reduce the sound transmission coefficient by about 33 %, 27.25 %, and 8.44 %. The transmission coefficient of acoustic energy decreases with the decrease of microcolumn array porosity. With the increase in temperature, the acoustic energy transmission loss curve shifts to high frequency, which is conducive to weakening the influence of the viscous dissipation effect on acoustic energy loss. The results are significant for understanding the sound transmission mechanism in microstructures.
