Based on the split hopkinson pressure bar(SHPB)tests results,the cubic specimens have been numerically modeled in this paper to investigate the impact of key factors,such as the rise time,duration,and incident pulse s...Based on the split hopkinson pressure bar(SHPB)tests results,the cubic specimens have been numerically modeled in this paper to investigate the impact of key factors,such as the rise time,duration,and incident pulse shape,on achieving stress uniformity.After analysis,the paper provides actionable methods aimed at optimizing the conditions for stress uniformity within the cubic specimen.Finally,the lateral inertia effect of cubic specimen has been scrutinized to address the existing gap in this academic area.展开更多
Improving plasma uniformity is a critical issue in the development of large-area radio-frequency(RF)inductively coupled plasma(ICP)sources.In this work,the effects of coil structure and electromagnetic shielding on th...Improving plasma uniformity is a critical issue in the development of large-area radio-frequency(RF)inductively coupled plasma(ICP)sources.In this work,the effects of coil structure and electromagnetic shielding on the spatial distribution and uniformity of the plasma are systematically investigated using a three-dimensional fluid model.The model integrates plasma and electromagnetic field modules to simulate the discharge characteristics of a large-area RF ICP source with dimensions of 100 cm×50 cm.The results reveal that the electron density distribution varies significantly with the coil structure.For the rotating and translating coil structures,the electron density is high at off-axis positions and low at the center.In contrast,the mirror coil structure exhibits a significantly higher electron density at the chamber center,resulting in a high-center and low-edge density distribution.Among the three configurations,the rotating coil structure provides the best plasma uniformity.The incorporation of electromagnetic shielding further improves plasma uniformity,particularly for the mirror coil structure.For the rotating and translating coil structures,the electron density exhibits a saddle-shaped distribution regardless of electromagnetic shielding.However,introducing electromagnetic shielding into the mirror coil structure reduces the electron density at the chamber center and decreases the non-uniformity degree by 18.4%.Overall,the mirror coil structure with electromagnetic shielding achieves the highest uniformity,with an exceptional plasma uniformity of 94%.This work offers valuable insights for the design of large-area ICP sources in advanced plasma processing systems.展开更多
Biodiversity has always been valued by ecology,Diversity is generally believed to lead to stability,and biodiversity is an important condition for ecosystems to maintain health.So what factors are related to forest ec...Biodiversity has always been valued by ecology,Diversity is generally believed to lead to stability,and biodiversity is an important condition for ecosystems to maintain health.So what factors are related to forest ecosystem biodiversity,and what kind of forest structure affects and determines the size of biodiversity.This study proposes the concept of contained uniformity based on the theory of uniformity,and uses the convergence of contained uniformity to obtain the judgment model of the forest station pattern type.At the same time,it proposes the concept of forest ecosystem distance diversity,and uses the judgment model of the stand pattern type to derive the mathematical definition of forest ecosystem distance diversity.Combining the ecological characteristics of different stand patterns and measurement indicators of forest ecosystem biodiversity,the connection between forest ecosystem distance diversity and biodiversity is derived,and this is used as an indicator to evaluate forest ecosystem biodiversity.Forest ecosystem distance diversity,as an indicator of biodiversity,can not only conduct early assessment and prediction of the biodiversity of immature forests(forests in the early succession or recovery stage),but also provide a quantitative basis for forest structure optimization.Ultimately realize the sustainable development of forestry production and operation and biodiversity protection.展开更多
On the morning of May 31st,the parallel forum"Seeking Harmony without Uniformity in Mutual Learning:Diversity of Civilisations from the Sinologists'Perspective"was held in Dunhuang.The forum was hosted b...On the morning of May 31st,the parallel forum"Seeking Harmony without Uniformity in Mutual Learning:Diversity of Civilisations from the Sinologists'Perspective"was held in Dunhuang.The forum was hosted by the Chinese Association for International Understanding and organised by Beijing Language and Culture University.Leading Sinologists and Chinese culture researchers from Europe,Asia and Latin America gathered to discuss the theme of civilisational diversity and explore pathways for coexistence and mutual enrichment.展开更多
The double-sided lapping process is extensively employed in the manufacturing of wafers,optical windows,and seal rings due to its high efficiency and ability to achieve precise flatness.However,limited research has ex...The double-sided lapping process is extensively employed in the manufacturing of wafers,optical windows,and seal rings due to its high efficiency and ability to achieve precise flatness.However,limited research has explored the thickness uniformity among different workpieces after double-sided lapping,and the underlying mechanism remains unclear.To address the demand for higher precision,this paper first analyzed the relative kinematic model between the workpiece and the lapping plate to clarify the causes of thickness variations among workpieces after double-sided lapping.Subsequently,a finite element method(FEM)model was developed to account for the pressure distribution on the workpiece surfaces at the initial stage of the process.The results indicate that the number of workpieces influences the final thickness variation.Then,various sets of thin copper plates with different thicknesses were lapped,and the findings revealed that five copper plates processed simultaneously exhibited more uniform thickness compared to the three plates.The experimental results align well with the theoretical analysis.Ultimately,a thickness variation of less than 6μm was achieved on five copper plates measuringΦ100×2.9 mm.This study presents a comprehensive analysis of the mechanisms influencing thickness uniformity in the double-sided lapping process and provides practical guidelines for optimizing the process to achieve stringent precision standards in industrial applications.展开更多
At present,the naked-eye three-dimensional(3D)display technology still has some drawbacks,such as low brightness uniformity,high crosstalk,low light efficiency,short viewing distance,and the manufacturing is difficult...At present,the naked-eye three-dimensional(3D)display technology still has some drawbacks,such as low brightness uniformity,high crosstalk,low light efficiency,short viewing distance,and the manufacturing is difficulty.Based on the principle of naked-eye 3D display and the Fresnel optical theory,this paper designs a Fresnel lens array and the star-shaped liquid crystal display(LCD)switch of unit LCD screen to achieve low-crosstalk and high brightness uniformity for the autostereoscopic 3D display.The unit parameters of a 139.7 cm 4K model autostereoscopic 3D displayer are provided and they are optimized by the TracePro software.The results show that when the pitch of the Fresnel lens on the exit surface is 0.304 mm,the width of each serration of Fresnel lens is 0.0234 mm,the length of the Fresnel lens is 2.87 mm,and the center height of star-shaped LCD switch is 0.030 mm,the center length is 0.040 mm,the width of star-shaped LCD switch is 0.050 mm,and the image crosstalk is less than 2%when the viewing distance is 2.50 m.The problem on the brightness of the image in different positions is improved.展开更多
Emerging bio-inspired computing systems simulate the cognitive functions of the brain for the realiza-tion of future computing systems.For the development of such efficient neuromorphic electronics,the emulation of sh...Emerging bio-inspired computing systems simulate the cognitive functions of the brain for the realiza-tion of future computing systems.For the development of such efficient neuromorphic electronics,the emulation of short-term and long-term synaptic plasticity behaviors of the biological synapses is an es-sential step.However,the electronic synaptic devices suffer from higher variability issues which hinder the application of such devices to build neuromorphic systems.For practical applications,it is essen-tial to minimize the cycle-to-cycle and device-to-device variations in the synaptic functions of artifi-cial electronic synapses.This study involves the fabrication of diffusive memristor devices using WTe_(2) chalcogenide as the main switching material.The choice of the switching material provides a facile so-lution to the variability problem.The greater uniformity in the switching characteristics of the WTe_(2)-based memristor offers higher uniformity for the synaptic emulation.These devices exhibit both volatile and nonvolatile switching properties,allowing them to emulate both short-term and long-term synaptic functions.The WTe_(2)-based electronic synaptic devices present a high degree of uniformity for the emula-tion of various essential biological synaptic functions including short-term potentiation(STP),long-term potentiation(LTP),long-term depression(LTD),spike-rate-dependent plasticity(SRDP),and spike-timing-dependent plasticity(STDP).A higher recognition accuracy of∼92%is attained for pattern recognition using the modified National Institute of Standards and Technology(MNIST)handwritten digits,which is attributed to the enhanced linearity and higher uniformity of LTP/LTD characteristics.展开更多
The mineralization process of microbial-induced calcium carbonate precipitation(MICP)is influenced by many factors,and the uniformity of the calcium carbonate precipitation has become the main focus and challenge for ...The mineralization process of microbial-induced calcium carbonate precipitation(MICP)is influenced by many factors,and the uniformity of the calcium carbonate precipitation has become the main focus and challenge for MICP technology.In this study,the uniformity of the saturated calcareous sand treated with MICP was in-vestigated through one-dimensional calcareous sand column tests and model tests.The coefficient of variation was employed in one-dimensional sand column tests to investigate the impact of injection rate,cementation solution concentration,and number of injection cycles on the uniformity of the MICP treatment.Additionally,model tests were conducted to investigate the impact of injection pressure and methods on the treatment range and uniformity under three-dimensional seepage conditions.Test results demonstrate that the reinforcement strength and uniformity are significantly influenced by the injection rate of the cementation solution,with a rate of 3 mL/min,yielding a favorable treatment effect.Excessive concentration of the cementation solution can lead to significant non-uniformity and a reduction in the compressive strength of MICP-treated samples.Conversely,excessively low concentrations may result in decreased bonding efficiency.Among the four considered con-centrations,0.5 mol/L and 1 mol/L exhibit superior reinforcing effects.The morphological development of calcareous sandy foundation reinforcement is associated with the spatial distribution pattern of the bacterial solution,exhibiting a relatively larger reinforcement area in proximity to the lower region of the model and a gradually decreasing range towards the upper part.Under three-dimensional seepage conditions,in addition to the non-uniform radial cementation along the injection pipe,there is also vertical heterogeneity of cementation along the length of the injection pipe due to gravitational effects,resulting in preferential deposition of calcium carbonate at the lower section,The application of injection pressure and a double-pipe circulation injection method can mitigate the accumulation of bacterial solution and cementation solution at the bottom,thereby improving the reinforcement range and uniformity.展开更多
To improve the quality of the illumination distribution,one novel indoor visible light communication(VLC)system,which is jointly assisted by the angle-diversity transceivers and simultaneous transmission and reflectio...To improve the quality of the illumination distribution,one novel indoor visible light communication(VLC)system,which is jointly assisted by the angle-diversity transceivers and simultaneous transmission and reflection-intelligent reflecting surface(STAR-IRS),has been proposed in this work.A Harris Hawks optimizer algorithm(HHOA)-based two-stage alternating iteration algorithm(TSAIA)is presented to jointly optimize the magnitude and uniformity of the received optical power.Besides,to demonstrate the superiority of the proposed strategy,several benchmark schemes are simulated and compared.Results showed that compared to other optimization strategies,the TSAIA scheme is more capable of balancing the average value and variance of the received optical power,when the maximal ratio combining(MRC)strategy is adopted at the receiver.Moreover,as the number of the STAR-IRS elements increases,the optical power variance of the system optimized by TSAIA scheme would become smaller while the average optical power would get larger.This study will benefit the design of received optical power distribution for indoor VLC systems.展开更多
Ceramic hollow spheres have great potential for deep-sea applications.However,the irregularity of the conventional molding process,among other reasons,results in low wall thickness uniformity of hollow spheres.To solv...Ceramic hollow spheres have great potential for deep-sea applications.However,the irregularity of the conventional molding process,among other reasons,results in low wall thickness uniformity of hollow spheres.To solve this problem,in this work,we developed a biaxial rotation grouting process for deep-sea ceramic hollow buoyancy spheres,which improves the drawbacks of the traditional rotary grouting method that results in poor wall thickness uniformity of the hollow spheres due to its irregular rotational processing.In this paper,an experimental study was carried out to investigate the effects of different rotational methods,rotational speeds,rotational time,solid phase content,etc.on the wall thickness uniformity of ceramic hollow spheres.The results show that the hollow floating balls prepared by the biaxial rotation method have the lowest wall thickness standard deviation(0.04)when the rotation speed is 60 rpm,the molding time is 8 min,and the solid phase content is 70 wt%.After the hydrostatic pressure test of 120 MPa,the hydrostatic compressive strength of hollow spheres prepared by the biaxial rotation method was increased by 31.67%compared with that of the traditional process.展开更多
The practical application of lithium(Li)metal batteries(LMBs)faces challenges due to the irreversible Li deposition/dissolution process,which promotes Li dendrite growth with severe parasitic reactions during cycling....The practical application of lithium(Li)metal batteries(LMBs)faces challenges due to the irreversible Li deposition/dissolution process,which promotes Li dendrite growth with severe parasitic reactions during cycling.To address these issues,achieving uniform Li‐ion flux and improving Li‐ion conductivity of the separator are the top priorities.Herein,a separator(PCELS)with enhanced Li‐ion conductivity,composed of polymer,ceramic,and electrically conductive carbon,is proposed to facilitate fast Li‐ion transport kinetics and increase Li deposition uniformity of the LMBs.The PCELS immobilizes PF6–anions with high adsorption energies,leading to a high Li‐ion transference number.Simultaneously,the PCELS shows excellent electrolyte wettability on both its sides,promoting rapid ion transport.Moreover,the electrically conductive carbon within the PCELS provides additional electron transport channels,enabling efficient charge transfer and uniform Li‐ion flux.With these advantages,the PCELS achieves rapid Li‐ion transport kinetics and uniform Li deposition,demonstrating excellent cycling stability over 100 cycles at a high current density of 12.0 mA cm^(-2).Furthermore,the PCELS shows stable cycling performances in Li–S cell tests and delivers an excellent capacity retention of 95.45%in the Li|LiFePO_(4) full‐cell test with a high areal capacity of over 5.5 mAh cm^(-2).展开更多
The effect of forging passes on the refinement of high purity aluminum during multi-forging was investigated. The attention was focused on the structure uniformity due to deformation uniformity and the grain refinemen...The effect of forging passes on the refinement of high purity aluminum during multi-forging was investigated. The attention was focused on the structure uniformity due to deformation uniformity and the grain refinement limitation with very high strains. The results show that the fine grain zone in the center of sample expands gradually with the increase of forging passes. When the forging passes reach 6, an X-shape fine grain zone is initially formed. With a further increase of the passes, this X-shape zone tends to spread the whole sample. Limitation in the structural refinement is observed with increasing strains during multi-forging process at the room temperature. The grains size in the center is refined to a certain size （110 μm as forging passes reach 12, and there is no further grain refinement in the center with increasing the forging passes to 24. However, the size of the coarse grains near the surface is continuously decreased with increasing the forging passes to 24.展开更多
基金Funded by the National Natural Science Foundation of China(Nos.52278518 and 51938011)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.24KJB560021)。
文摘Based on the split hopkinson pressure bar(SHPB)tests results,the cubic specimens have been numerically modeled in this paper to investigate the impact of key factors,such as the rise time,duration,and incident pulse shape,on achieving stress uniformity.After analysis,the paper provides actionable methods aimed at optimizing the conditions for stress uniformity within the cubic specimen.Finally,the lateral inertia effect of cubic specimen has been scrutinized to address the existing gap in this academic area.
基金supported by the National Natural Science Foundation of China(Grant Nos.12075049 and 11935005)。
文摘Improving plasma uniformity is a critical issue in the development of large-area radio-frequency(RF)inductively coupled plasma(ICP)sources.In this work,the effects of coil structure and electromagnetic shielding on the spatial distribution and uniformity of the plasma are systematically investigated using a three-dimensional fluid model.The model integrates plasma and electromagnetic field modules to simulate the discharge characteristics of a large-area RF ICP source with dimensions of 100 cm×50 cm.The results reveal that the electron density distribution varies significantly with the coil structure.For the rotating and translating coil structures,the electron density is high at off-axis positions and low at the center.In contrast,the mirror coil structure exhibits a significantly higher electron density at the chamber center,resulting in a high-center and low-edge density distribution.Among the three configurations,the rotating coil structure provides the best plasma uniformity.The incorporation of electromagnetic shielding further improves plasma uniformity,particularly for the mirror coil structure.For the rotating and translating coil structures,the electron density exhibits a saddle-shaped distribution regardless of electromagnetic shielding.However,introducing electromagnetic shielding into the mirror coil structure reduces the electron density at the chamber center and decreases the non-uniformity degree by 18.4%.Overall,the mirror coil structure with electromagnetic shielding achieves the highest uniformity,with an exceptional plasma uniformity of 94%.This work offers valuable insights for the design of large-area ICP sources in advanced plasma processing systems.
基金funded by Research on Intelligent Control System of Variable Fertilization of Deep Application Liquid Fertilizer(GXKS2022GKY003)the Key Laboratory of Smart Agriculture Technology,Guangxi Science and Technology Normal University(GXKSKYPT2024008)+1 种基金Key Laboratory of Detection Technology for Sugarcane and Peanut Leaf Spot Disease,Guangxi Science and Technology Normal University(GXKSKYPT2025008)Research on the Application of Uniformity Theory and 3D Virtual Forest Phase in Harbin Normal University’s Science and Technology Innovation Climbing Program Funding Project(XKB202415)。
文摘Biodiversity has always been valued by ecology,Diversity is generally believed to lead to stability,and biodiversity is an important condition for ecosystems to maintain health.So what factors are related to forest ecosystem biodiversity,and what kind of forest structure affects and determines the size of biodiversity.This study proposes the concept of contained uniformity based on the theory of uniformity,and uses the convergence of contained uniformity to obtain the judgment model of the forest station pattern type.At the same time,it proposes the concept of forest ecosystem distance diversity,and uses the judgment model of the stand pattern type to derive the mathematical definition of forest ecosystem distance diversity.Combining the ecological characteristics of different stand patterns and measurement indicators of forest ecosystem biodiversity,the connection between forest ecosystem distance diversity and biodiversity is derived,and this is used as an indicator to evaluate forest ecosystem biodiversity.Forest ecosystem distance diversity,as an indicator of biodiversity,can not only conduct early assessment and prediction of the biodiversity of immature forests(forests in the early succession or recovery stage),but also provide a quantitative basis for forest structure optimization.Ultimately realize the sustainable development of forestry production and operation and biodiversity protection.
文摘On the morning of May 31st,the parallel forum"Seeking Harmony without Uniformity in Mutual Learning:Diversity of Civilisations from the Sinologists'Perspective"was held in Dunhuang.The forum was hosted by the Chinese Association for International Understanding and organised by Beijing Language and Culture University.Leading Sinologists and Chinese culture researchers from Europe,Asia and Latin America gathered to discuss the theme of civilisational diversity and explore pathways for coexistence and mutual enrichment.
基金Supported by the Liaoning Provincial Natural Science Foundation(Grant No.2023-MSBA-008)Unveiling and Commanding Program of Liaoning Province(Grant No.2022JH1/10800080)the Fundamental Research Funds for the Central Universities(Grant No.DUT24MS008).
文摘The double-sided lapping process is extensively employed in the manufacturing of wafers,optical windows,and seal rings due to its high efficiency and ability to achieve precise flatness.However,limited research has explored the thickness uniformity among different workpieces after double-sided lapping,and the underlying mechanism remains unclear.To address the demand for higher precision,this paper first analyzed the relative kinematic model between the workpiece and the lapping plate to clarify the causes of thickness variations among workpieces after double-sided lapping.Subsequently,a finite element method(FEM)model was developed to account for the pressure distribution on the workpiece surfaces at the initial stage of the process.The results indicate that the number of workpieces influences the final thickness variation.Then,various sets of thin copper plates with different thicknesses were lapped,and the findings revealed that five copper plates processed simultaneously exhibited more uniform thickness compared to the three plates.The experimental results align well with the theoretical analysis.Ultimately,a thickness variation of less than 6μm was achieved on five copper plates measuringΦ100×2.9 mm.This study presents a comprehensive analysis of the mechanisms influencing thickness uniformity in the double-sided lapping process and provides practical guidelines for optimizing the process to achieve stringent precision standards in industrial applications.
基金supported by the 2022 Fujian Provincial Young and Middle-aged Teacher Education and Research Project(Science and Technology)(No.JAT220468)the Xiamen Natural Science Foundation(No.3502Z20227334).
文摘At present,the naked-eye three-dimensional(3D)display technology still has some drawbacks,such as low brightness uniformity,high crosstalk,low light efficiency,short viewing distance,and the manufacturing is difficulty.Based on the principle of naked-eye 3D display and the Fresnel optical theory,this paper designs a Fresnel lens array and the star-shaped liquid crystal display(LCD)switch of unit LCD screen to achieve low-crosstalk and high brightness uniformity for the autostereoscopic 3D display.The unit parameters of a 139.7 cm 4K model autostereoscopic 3D displayer are provided and they are optimized by the TracePro software.The results show that when the pitch of the Fresnel lens on the exit surface is 0.304 mm,the width of each serration of Fresnel lens is 0.0234 mm,the length of the Fresnel lens is 2.87 mm,and the center height of star-shaped LCD switch is 0.030 mm,the center length is 0.040 mm,the width of star-shaped LCD switch is 0.050 mm,and the image crosstalk is less than 2%when the viewing distance is 2.50 m.The problem on the brightness of the image in different positions is improved.
基金supported by the Singapore Ministry of Educa-tion under Research(Grant no.MOE-T2EP50120-0003).
文摘Emerging bio-inspired computing systems simulate the cognitive functions of the brain for the realiza-tion of future computing systems.For the development of such efficient neuromorphic electronics,the emulation of short-term and long-term synaptic plasticity behaviors of the biological synapses is an es-sential step.However,the electronic synaptic devices suffer from higher variability issues which hinder the application of such devices to build neuromorphic systems.For practical applications,it is essen-tial to minimize the cycle-to-cycle and device-to-device variations in the synaptic functions of artifi-cial electronic synapses.This study involves the fabrication of diffusive memristor devices using WTe_(2) chalcogenide as the main switching material.The choice of the switching material provides a facile so-lution to the variability problem.The greater uniformity in the switching characteristics of the WTe_(2)-based memristor offers higher uniformity for the synaptic emulation.These devices exhibit both volatile and nonvolatile switching properties,allowing them to emulate both short-term and long-term synaptic functions.The WTe_(2)-based electronic synaptic devices present a high degree of uniformity for the emula-tion of various essential biological synaptic functions including short-term potentiation(STP),long-term potentiation(LTP),long-term depression(LTD),spike-rate-dependent plasticity(SRDP),and spike-timing-dependent plasticity(STDP).A higher recognition accuracy of∼92%is attained for pattern recognition using the modified National Institute of Standards and Technology(MNIST)handwritten digits,which is attributed to the enhanced linearity and higher uniformity of LTP/LTD characteristics.
基金support of Natural Science Foundation of China(Grant No.52108324,No.52008207,and No.52108298)for conducting this study.
文摘The mineralization process of microbial-induced calcium carbonate precipitation(MICP)is influenced by many factors,and the uniformity of the calcium carbonate precipitation has become the main focus and challenge for MICP technology.In this study,the uniformity of the saturated calcareous sand treated with MICP was in-vestigated through one-dimensional calcareous sand column tests and model tests.The coefficient of variation was employed in one-dimensional sand column tests to investigate the impact of injection rate,cementation solution concentration,and number of injection cycles on the uniformity of the MICP treatment.Additionally,model tests were conducted to investigate the impact of injection pressure and methods on the treatment range and uniformity under three-dimensional seepage conditions.Test results demonstrate that the reinforcement strength and uniformity are significantly influenced by the injection rate of the cementation solution,with a rate of 3 mL/min,yielding a favorable treatment effect.Excessive concentration of the cementation solution can lead to significant non-uniformity and a reduction in the compressive strength of MICP-treated samples.Conversely,excessively low concentrations may result in decreased bonding efficiency.Among the four considered con-centrations,0.5 mol/L and 1 mol/L exhibit superior reinforcing effects.The morphological development of calcareous sandy foundation reinforcement is associated with the spatial distribution pattern of the bacterial solution,exhibiting a relatively larger reinforcement area in proximity to the lower region of the model and a gradually decreasing range towards the upper part.Under three-dimensional seepage conditions,in addition to the non-uniform radial cementation along the injection pipe,there is also vertical heterogeneity of cementation along the length of the injection pipe due to gravitational effects,resulting in preferential deposition of calcium carbonate at the lower section,The application of injection pressure and a double-pipe circulation injection method can mitigate the accumulation of bacterial solution and cementation solution at the bottom,thereby improving the reinforcement range and uniformity.
基金supported by the National Natural Science Foundation of China(No.62071365)the Key Research and Development Program of Shaanxi Province(No.2017ZDCXL-GY-06-02).
文摘To improve the quality of the illumination distribution,one novel indoor visible light communication(VLC)system,which is jointly assisted by the angle-diversity transceivers and simultaneous transmission and reflection-intelligent reflecting surface(STAR-IRS),has been proposed in this work.A Harris Hawks optimizer algorithm(HHOA)-based two-stage alternating iteration algorithm(TSAIA)is presented to jointly optimize the magnitude and uniformity of the received optical power.Besides,to demonstrate the superiority of the proposed strategy,several benchmark schemes are simulated and compared.Results showed that compared to other optimization strategies,the TSAIA scheme is more capable of balancing the average value and variance of the received optical power,when the maximal ratio combining(MRC)strategy is adopted at the receiver.Moreover,as the number of the STAR-IRS elements increases,the optical power variance of the system optimized by TSAIA scheme would become smaller while the average optical power would get larger.This study will benefit the design of received optical power distribution for indoor VLC systems.
基金Funded by the Key Research and Development Program of Shandong Province(No.2020JMRH0101)。
文摘Ceramic hollow spheres have great potential for deep-sea applications.However,the irregularity of the conventional molding process,among other reasons,results in low wall thickness uniformity of hollow spheres.To solve this problem,in this work,we developed a biaxial rotation grouting process for deep-sea ceramic hollow buoyancy spheres,which improves the drawbacks of the traditional rotary grouting method that results in poor wall thickness uniformity of the hollow spheres due to its irregular rotational processing.In this paper,an experimental study was carried out to investigate the effects of different rotational methods,rotational speeds,rotational time,solid phase content,etc.on the wall thickness uniformity of ceramic hollow spheres.The results show that the hollow floating balls prepared by the biaxial rotation method have the lowest wall thickness standard deviation(0.04)when the rotation speed is 60 rpm,the molding time is 8 min,and the solid phase content is 70 wt%.After the hydrostatic pressure test of 120 MPa,the hydrostatic compressive strength of hollow spheres prepared by the biaxial rotation method was increased by 31.67%compared with that of the traditional process.
基金supported by Ministry of Science and ICT,South Korea(RS‐2024‐00407282)National Research Foundation of Korea(RS‐2024‐00408156).
文摘The practical application of lithium(Li)metal batteries(LMBs)faces challenges due to the irreversible Li deposition/dissolution process,which promotes Li dendrite growth with severe parasitic reactions during cycling.To address these issues,achieving uniform Li‐ion flux and improving Li‐ion conductivity of the separator are the top priorities.Herein,a separator(PCELS)with enhanced Li‐ion conductivity,composed of polymer,ceramic,and electrically conductive carbon,is proposed to facilitate fast Li‐ion transport kinetics and increase Li deposition uniformity of the LMBs.The PCELS immobilizes PF6–anions with high adsorption energies,leading to a high Li‐ion transference number.Simultaneously,the PCELS shows excellent electrolyte wettability on both its sides,promoting rapid ion transport.Moreover,the electrically conductive carbon within the PCELS provides additional electron transport channels,enabling efficient charge transfer and uniform Li‐ion flux.With these advantages,the PCELS achieves rapid Li‐ion transport kinetics and uniform Li deposition,demonstrating excellent cycling stability over 100 cycles at a high current density of 12.0 mA cm^(-2).Furthermore,the PCELS shows stable cycling performances in Li–S cell tests and delivers an excellent capacity retention of 95.45%in the Li|LiFePO_(4) full‐cell test with a high areal capacity of over 5.5 mAh cm^(-2).
基金Projects(51204053,51074048,51204048)supported by the National Natural Science Foundation of ChinaProject(20110491518)supported by China Postdoctoral Science FoundationProject(2012CB619506)supported by the National Basic Research Program of China
文摘The effect of forging passes on the refinement of high purity aluminum during multi-forging was investigated. The attention was focused on the structure uniformity due to deformation uniformity and the grain refinement limitation with very high strains. The results show that the fine grain zone in the center of sample expands gradually with the increase of forging passes. When the forging passes reach 6, an X-shape fine grain zone is initially formed. With a further increase of the passes, this X-shape zone tends to spread the whole sample. Limitation in the structural refinement is observed with increasing strains during multi-forging process at the room temperature. The grains size in the center is refined to a certain size （110 μm as forging passes reach 12, and there is no further grain refinement in the center with increasing the forging passes to 24. However, the size of the coarse grains near the surface is continuously decreased with increasing the forging passes to 24.
