Atomically precise coordination nanoclusters(NCs)constitute a pivotal and rapidly advancing domain in the realms of materials science and chemistry owing to their distinctive crystal structures and exceptional attribu...Atomically precise coordination nanoclusters(NCs)constitute a pivotal and rapidly advancing domain in the realms of materials science and chemistry owing to their distinctive crystal structures and exceptional attributes encompassing molecular magnetism[1],photoluminescence[2],and catalysis[3].Organic ligands play a crucial role in effectively shielding these NCs,serving two primary functions:firstly,vital in preventing NC aggregation,particularly for the formation of robust single-crystal structures;secondly,acting as either bridging or peripheral structural components of NCs[4].This characterization of organic-inorganic hybridization offers unique advantages for unraveling the intricate relationships between structure and properties[5].展开更多
Maize/soybean intercropping systems are commonly used in developing countries,but few studies have been performed to elucidate the differences in nutrient efficiency and rhizosphere microbiome,especially when maize is...Maize/soybean intercropping systems are commonly used in developing countries,but few studies have been performed to elucidate the differences in nutrient efficiency and rhizosphere microbiome,especially when maize is intercropped with different soybean varieties.In this study,field experiments were conducted to compare the growth and yield of two soybean(Glycine max)varieties,BD2 and YC03-3,and one maize(Zea mays)variety,Huazhen,in mono-cropped and intercropped cultures.The plant biomass and N content of both crops in BD2/maize intercropping were significantly improved compared to their monoculture,but no such effects were observed in the plants of YC03-3/maize intercropping.The yield of BD2 intercropped with maize exhibited a 37.5%increment above that of BD2 in monoculture.Moreover,19.2-29.1%longer root length of maize and 19.0-39.4%larger root volume of BD2 were observed in BD2/maize intercropping than in monoculture,but no growth advantage was observed in YC03-3/maize intercropping.Maize showed root avoidance when intercropped with BD2,but space competition when intercropped with YC03-3.16S rRNA amplicon sequencing showed that compared with the monoculture system,rhizobacteria community composition in BD2/maize intercropping changed more significantly than that of the YC03-3/maize intercropping system.In BD2/maize intercropping,most of the rhizobacteria community biomarker bacteria of BD2 were positively correlated with plant biomass,as well as plant P and N content.Maize tended to recruit Rhizobiales and Proteobacteria,which showed positive correlation with plant biomass and N content,respectively,as well as soil available N.In conclusion,soybean varieties determined the advantages of maize/soybean intercropping through root-root interactions and modification of rhizobacteria communities.Our insight emphasizes a linkage between root traits and the rhizobacteria community,which shows the importance of optimizing intercropping systems by selection of appropriate crop varieties.展开更多
Non-noble-based single atomic catalysts have exhibited significant potential in electrochemical production of H_(2)O_(2)via twoelectron oxygen reduction reactions(2e^(-)ORR).However,constructing highly efficient and a...Non-noble-based single atomic catalysts have exhibited significant potential in electrochemical production of H_(2)O_(2)via twoelectron oxygen reduction reactions(2e^(-)ORR).However,constructing highly efficient and acid-resistant catalysts remains a challenge but significant.In this work,fullerene(C_(60))with abundant pentagonal inherent defects was employed as a carbon substrate to synthesize defect-rich nanocarbon electrocatalysts doped with NSCo single atoms and accompanied by metallic Co nanoparticles(CoSA/CoNP-NSDNC)for the first time.The electrochemical experiments demonstrate that the active sites of CoSA/CoNP-NSDNC are formed through the synergistic interaction between NSCo single atoms and Co nanoparticle clusters embedded within the carbon framework.The obtained CoSA/CoNPNSDNC catalyst exhibits an onset potential as 0.72 V versus RHE and achieves up to 90%H_(2)O_(2)selectivity over a wide potential range of 500 mV.Moreover,the as-obtained CoSA/CoNP-NSDNC configured as the cathode in a self-assembled flow cell under acidic conditions achieves a high H_(2)O_(2)production rate of 4206.96 mmol gcat^(-1 )h^(-1) with a Faraday efficiency of∼95%and exhibit ultra fast degradation of organic pollutants.This work focuses on the synergistic effect of non-noble metal nanoparticles,metal single-atom sites,and topological defects on the 2e^(-)ORR process,which provides a new direction for designing carbon-based catalysts for efficient H_(2)O_(2)electrosynthesis.展开更多
Leveraging the high resolution,sensitivity,and wide frequency coverage of the Atacama Large Millimeter/submillimeter Array(ALMA),the QUARKS survey,standing for“Querying Underlying mechanisms of massive star formation...Leveraging the high resolution,sensitivity,and wide frequency coverage of the Atacama Large Millimeter/submillimeter Array(ALMA),the QUARKS survey,standing for“Querying Underlying mechanisms of massive star formation with ALMA-Resolved gas Kinematics and Structures”,is observing 139 massive starforming clumps at ALMA Band 6(λ~1.3 mm).This paper introduces the Atacama Compact Array(ACA)7 m data of the QUARKS survey,describing the ACA observations and data reduction.Combining multiwavelength data,we provide the first edition of QUARKS atlas,offering insights into the multiscale and multiphase interstellar medium in high-mass star formation.The ACA 1.3 mm catalog includes 207 continuum sources that are called ACA sources.Their gas kinetic temperatures are estimated using three formaldehyde transitions with a non-LTE radiation transfer model,and the mass and density are derived from a dust emission model.The ACA sources are massive(16–84 percentile values of 6–160 M_(⊙)),gravity-dominated(M∝R^(1.1))fragments within massive clumps,with supersonic turbulence(M>1)and embedded star-forming protoclusters.We find a linear correlation between the masses of the fragments and the massive clumps,with a ratio of 6%between the two.When considering fragments as representative of dense gas,the ratio indicates a dense gas fraction(DGF)of 6%,although with a wide scatter ranging from 1%to 10%.If we consider the QUARKS massive clumps to be what is observed at various scales,then the size-independent DGF indicates a self-similar fragmentation or collapsing mode in protocluster formation.With the ACA data over four orders of magnitude of luminosity-to-mass ratio(L/M),we find that the DGF increases significantly with L/M,which indicates clump evolutionary stage.We observed a limited fragmentation at the subclump scale,which can be explained by a dynamic global collapse process.展开更多
The impacts of four different car-following types on rear-end crash risks at a freeway weaving section were evaluated using trajectory data, in which Type 1 represents car following car, Type 2 represents car followin...The impacts of four different car-following types on rear-end crash risks at a freeway weaving section were evaluated using trajectory data, in which Type 1 represents car following car, Type 2 represents car following truck, Type 3represents truck following car and Type 4 represents truck following truck. The time to collision( TTC) was introduced as the surrogate safety measure to determine the rear-end crash risks. Then, the trajectory data at a freeway weaving section was used for the case-controlled analysis. Three logistic regression models were developed with different TTC thresholds to quantify the impacts of different car-following types. The explanatory factors were also analyzed to investigate possible reasons for the results of logistic regressions. Results showthat the rear-end crash risk of Type3 is 3. 167 times higher than that of Type 1 when the TTC threshold is 2 s. However, the odds ratios of Type 2 and Type4 are both smaller than 1, which indicates a safer condition.The analysis of explanatory factors also shows that Type 3 has the largest speed differences and the smallest net gaps. This is consistent with vehicle operation features at a weaving section and is also the reason for the larger rear-end crash risks. The results of this study reflect the mechanism of rear-end crash risks of different car-following types at the freeway weaving section.展开更多
Porous Ti samples were fabricated by powder metallurgy technique using three kinds of Ti powder and the space holder of polymethyl methacrylate. The final morphological features and mechanical properties were describe...Porous Ti samples were fabricated by powder metallurgy technique using three kinds of Ti powder and the space holder of polymethyl methacrylate. The final morphological features and mechanical properties were described. Results show that there is only α-Ti phase in porous Ti samples. After sintering, the oxygen content of three porous Ti is increased from the range of 0.34-0.63 wt% to 0.95-1.3 wt%. The porous Ti prepared from the uneven powders with an average particle size of （22.75 ±11.09） μm presents the largest micro-pore size, grain size, and oxygen content, which lead to the lowest strength and Young＇s modulus.展开更多
Oxygen evolution reaction(OER)plays a crucial role in regulating the process of hydrogen production from water splitting where an expeditious,stable and low-cost electrocatalyst is urgently required.By employing a fac...Oxygen evolution reaction(OER)plays a crucial role in regulating the process of hydrogen production from water splitting where an expeditious,stable and low-cost electrocatalyst is urgently required.By employing a facile strategy of selective phase dissolution,this dissertation attempts to illuminate the successful preparation of a porous AlCoCrFeNi high-entropy alloy(SPD-48 h).展开更多
为精确刻画匝道合流区客货混行条件下的车辆微观换道行为,本文以量化客货交互为切入点,构建并验证考虑货车影响的微观换道模型。首先,引入“压迫”概念,构建改进Morse势函数模型描述周边货车行驶对小汽车横纵驾驶行为产生的“压迫”影响...为精确刻画匝道合流区客货混行条件下的车辆微观换道行为,本文以量化客货交互为切入点,构建并验证考虑货车影响的微观换道模型。首先,引入“压迫”概念,构建改进Morse势函数模型描述周边货车行驶对小汽车横纵驾驶行为产生的“压迫”影响;随后,分析小汽车换道过程中的横纵向“压迫”变化,提出一种考虑货车“压迫”影响的车辆换道决策模型(Modified Morse-Based Lane-Changing model,MMBLC);最后,基于实测轨迹数据进行数值仿真,验证模型的稳定性与有效性,并进一步利用Python与SUMO(Simulation of Urban Mobility)联合仿真,对比MMBLC模型和现有换道模型在交通流中的表现。结果表明:在稳定性分析中,MMBLC模型对交通流的影响更小,恢复稳定的速度更快;在货车占比30%和交通量3600 veh·h-1的主路3车道客货混行匝道合流区中,MMBLC模型相比LC2013和MOBIL(Model of Optimal Control Based on Interacting Trajectories)模型,换道成功率分别提高11.9%和53.1%,危险场景占比分别降低10.5%和52.8%。展开更多
In core-shell silver nanoclusters,the control of core structure presents a more formidable challenge compared to that of the shell structure.Here,we report the successful synthesis and characterization of four distinc...In core-shell silver nanoclusters,the control of core structure presents a more formidable challenge compared to that of the shell structure.Here,we report the successful synthesis and characterization of four distinct silver thiolate nanoclusters[MS_(4)@Ag_(12)@Ag_(46)S_(24)(dppb)_(12)](M=Mo or W),each incorporating a cup-like[MS_(4)@Ag_(12)]^(2+)kernel.These nanoclusters were meticulously prepared using(NH_(4))2Mo S4or(NH_(4))_(2)WS_(4)as both a template and a controlled source of S2-ions.Remarkably,we have observed a unique configuration within these eight-electron superatomic Ag_(58) nanoclusters,where the zerovalent Ag atoms reside exclusively within the inner[MS_(4)@Ag_(12)]^(2+)kernel.This stands in contrast to other superatomic clusters possessing an Ag(0)core.Notably,the introduction of phenyl-containing compounds during the synthesis process induced a transformation in the space group symmetry from C_(2)/c to I 4ˉ.This transformative effect was found to originate from the interplay between adjacent 1,4-bis(diphenylphosphino)butane(dppb)ligands,which facilitated enhanced emission through aggregationinduced intermolecular interactions,specifically C-H···πinteractions.Collectively,our findings contribute substantively to the understanding of the intricate relationship between nanocluster structures and their corresponding properties,shedding light on the crucial roles played by templates and diphosphine ligands in this context.展开更多
Journal misalignment is common in journal bearings. When severe journal misalignment takes place, it affects nearly all aspects of bearing performance. This paper provided a comprehensive analysis of misaligned journa...Journal misalignment is common in journal bearings. When severe journal misalignment takes place, it affects nearly all aspects of bearing performance. This paper provided a comprehensive analysis of misaligned journal bearings based on two different mass-conservative models which appropriately took into account film rupture and reformation. The lubrication characteristics and performance parameters including the cavitation zones, pressure distribution, density distribution, oil leakage, load capacity, moment, and attitude angle were compared with the traditional lubrication model. The results showed that cavitation has great effect on bearing performances, especially when the surface roughness is large. Therefore, it is necessary to consider the effects of journal misalignment alongside inter-asperity cavitation theory in the design and analyses of journal bearings.展开更多
高速公路客货混行场景下,客货车辆物理性能和驾驶行为差异易导致货车后方小汽车出现急加减速、超车等危险驾驶行为,影响交通流稳定性,加剧道路交通事故风险。鉴于此,聚焦于客货场景,创新性地以货车“压迫度”为切入点,探究客货车辆交互...高速公路客货混行场景下,客货车辆物理性能和驾驶行为差异易导致货车后方小汽车出现急加减速、超车等危险驾驶行为,影响交通流稳定性,加剧道路交通事故风险。鉴于此,聚焦于客货场景,创新性地以货车“压迫度”为切入点,探究客货车辆交互影响下小汽车的换道行为和行车风险。首先,引入分子相互作用力构建考虑驾驶风格的货车压迫度(Oppression Measurement of Truck,OMT)量化指标,以量化货车对小汽车行驶存在的压迫影响。进一步采用货车压迫度优化小汽车换道意图判别方法,并融合货车压迫度构建基于卷积神经网络-长短期记忆混合神经网络(CNN-LSTM)的换道意图识别模型和基于轻量级梯度提升机(LightGBM)的换道风险预测模型联合组成的两阶段换道风险预测模型,并采用车辆轨迹数据集验证模型的有效性。研究结果表明:有换道行为的车辆总体上受到更强烈的货车压迫;熟练型驾驶人能够容忍高强度的货车压迫,而谨慎型的驾驶人对货车压迫较为敏感,偏向于保持在低压迫度下行驶。其次,货车压迫度与行车冲突之间存在时间滞后相关效应,较强压迫度能影响车辆驾驶行为,进而引发行车风险变化。融合了货车压迫度指标的模型在换道意图识别与风险预测中表现出更高的精度,并且货车压迫度在换道风险预测模型中具有较高的特征贡献度,研究结果可为复杂交互场景的微观建模与主动安全管控提供全新视角和有效理论支撑。展开更多
基金financial support from the National Natural Science Foundation of China(Nos.22171094,21925104,92261204,and 22431005)Hubei Provincial Science and Technology Innovation Team Project[2022]The National Key R&D Program of China(No.2022YFB3807700)。
文摘Atomically precise coordination nanoclusters(NCs)constitute a pivotal and rapidly advancing domain in the realms of materials science and chemistry owing to their distinctive crystal structures and exceptional attributes encompassing molecular magnetism[1],photoluminescence[2],and catalysis[3].Organic ligands play a crucial role in effectively shielding these NCs,serving two primary functions:firstly,vital in preventing NC aggregation,particularly for the formation of robust single-crystal structures;secondly,acting as either bridging or peripheral structural components of NCs[4].This characterization of organic-inorganic hybridization offers unique advantages for unraveling the intricate relationships between structure and properties[5].
基金supported by the National Key Research and Development Program of China(2021YFF1000504 and 2023YFD1901300)the National Natural Science Foundation of China(32172658,32172659 and 32302662)the Natural Science Foundation of Guangdong Province,China(2021A1515010826).
文摘Maize/soybean intercropping systems are commonly used in developing countries,but few studies have been performed to elucidate the differences in nutrient efficiency and rhizosphere microbiome,especially when maize is intercropped with different soybean varieties.In this study,field experiments were conducted to compare the growth and yield of two soybean(Glycine max)varieties,BD2 and YC03-3,and one maize(Zea mays)variety,Huazhen,in mono-cropped and intercropped cultures.The plant biomass and N content of both crops in BD2/maize intercropping were significantly improved compared to their monoculture,but no such effects were observed in the plants of YC03-3/maize intercropping.The yield of BD2 intercropped with maize exhibited a 37.5%increment above that of BD2 in monoculture.Moreover,19.2-29.1%longer root length of maize and 19.0-39.4%larger root volume of BD2 were observed in BD2/maize intercropping than in monoculture,but no growth advantage was observed in YC03-3/maize intercropping.Maize showed root avoidance when intercropped with BD2,but space competition when intercropped with YC03-3.16S rRNA amplicon sequencing showed that compared with the monoculture system,rhizobacteria community composition in BD2/maize intercropping changed more significantly than that of the YC03-3/maize intercropping system.In BD2/maize intercropping,most of the rhizobacteria community biomarker bacteria of BD2 were positively correlated with plant biomass,as well as plant P and N content.Maize tended to recruit Rhizobiales and Proteobacteria,which showed positive correlation with plant biomass and N content,respectively,as well as soil available N.In conclusion,soybean varieties determined the advantages of maize/soybean intercropping through root-root interactions and modification of rhizobacteria communities.Our insight emphasizes a linkage between root traits and the rhizobacteria community,which shows the importance of optimizing intercropping systems by selection of appropriate crop varieties.
基金supported by the National Natural Science Foundation of China(22001084,21925104,and 52072107)Nature Science Research Project of Anhui province(2408085MB030)Research funds of Central Universities of Hefei University of Technology(JZ2024HGTB0244).
文摘Non-noble-based single atomic catalysts have exhibited significant potential in electrochemical production of H_(2)O_(2)via twoelectron oxygen reduction reactions(2e^(-)ORR).However,constructing highly efficient and acid-resistant catalysts remains a challenge but significant.In this work,fullerene(C_(60))with abundant pentagonal inherent defects was employed as a carbon substrate to synthesize defect-rich nanocarbon electrocatalysts doped with NSCo single atoms and accompanied by metallic Co nanoparticles(CoSA/CoNP-NSDNC)for the first time.The electrochemical experiments demonstrate that the active sites of CoSA/CoNP-NSDNC are formed through the synergistic interaction between NSCo single atoms and Co nanoparticle clusters embedded within the carbon framework.The obtained CoSA/CoNPNSDNC catalyst exhibits an onset potential as 0.72 V versus RHE and achieves up to 90%H_(2)O_(2)selectivity over a wide potential range of 500 mV.Moreover,the as-obtained CoSA/CoNP-NSDNC configured as the cathode in a self-assembled flow cell under acidic conditions achieves a high H_(2)O_(2)production rate of 4206.96 mmol gcat^(-1 )h^(-1) with a Faraday efficiency of∼95%and exhibit ultra fast degradation of organic pollutants.This work focuses on the synergistic effect of non-noble metal nanoparticles,metal single-atom sites,and topological defects on the 2e^(-)ORR process,which provides a new direction for designing carbon-based catalysts for efficient H_(2)O_(2)electrosynthesis.
基金upported by the National Natural Science Foundation of China(NSFC,Grant No.12033005)the National Key R&D Program of China(No.2022YFA1603102)+2 种基金the China Manned Space Project(CMS-CSST-2021-A09,CMS-CSST-2021-B06)the China-Chile Joint Research Fund(CCJRF No.2211)support from the Tianchi Talent Program of Xinjiang Uygur Autonomous Region。
文摘Leveraging the high resolution,sensitivity,and wide frequency coverage of the Atacama Large Millimeter/submillimeter Array(ALMA),the QUARKS survey,standing for“Querying Underlying mechanisms of massive star formation with ALMA-Resolved gas Kinematics and Structures”,is observing 139 massive starforming clumps at ALMA Band 6(λ~1.3 mm).This paper introduces the Atacama Compact Array(ACA)7 m data of the QUARKS survey,describing the ACA observations and data reduction.Combining multiwavelength data,we provide the first edition of QUARKS atlas,offering insights into the multiscale and multiphase interstellar medium in high-mass star formation.The ACA 1.3 mm catalog includes 207 continuum sources that are called ACA sources.Their gas kinetic temperatures are estimated using three formaldehyde transitions with a non-LTE radiation transfer model,and the mass and density are derived from a dust emission model.The ACA sources are massive(16–84 percentile values of 6–160 M_(⊙)),gravity-dominated(M∝R^(1.1))fragments within massive clumps,with supersonic turbulence(M>1)and embedded star-forming protoclusters.We find a linear correlation between the masses of the fragments and the massive clumps,with a ratio of 6%between the two.When considering fragments as representative of dense gas,the ratio indicates a dense gas fraction(DGF)of 6%,although with a wide scatter ranging from 1%to 10%.If we consider the QUARKS massive clumps to be what is observed at various scales,then the size-independent DGF indicates a self-similar fragmentation or collapsing mode in protocluster formation.With the ACA data over four orders of magnitude of luminosity-to-mass ratio(L/M),we find that the DGF increases significantly with L/M,which indicates clump evolutionary stage.We observed a limited fragmentation at the subclump scale,which can be explained by a dynamic global collapse process.
基金The National Natural Science Foundation of China(No.51638004,51338003,51478113)
文摘The impacts of four different car-following types on rear-end crash risks at a freeway weaving section were evaluated using trajectory data, in which Type 1 represents car following car, Type 2 represents car following truck, Type 3represents truck following car and Type 4 represents truck following truck. The time to collision( TTC) was introduced as the surrogate safety measure to determine the rear-end crash risks. Then, the trajectory data at a freeway weaving section was used for the case-controlled analysis. Three logistic regression models were developed with different TTC thresholds to quantify the impacts of different car-following types. The explanatory factors were also analyzed to investigate possible reasons for the results of logistic regressions. Results showthat the rear-end crash risk of Type3 is 3. 167 times higher than that of Type 1 when the TTC threshold is 2 s. However, the odds ratios of Type 2 and Type4 are both smaller than 1, which indicates a safer condition.The analysis of explanatory factors also shows that Type 3 has the largest speed differences and the smallest net gaps. This is consistent with vehicle operation features at a weaving section and is also the reason for the larger rear-end crash risks. The results of this study reflect the mechanism of rear-end crash risks of different car-following types at the freeway weaving section.
基金supported by Research Project from Education Office of Liaoning Province in China (No.20060103)
文摘Porous Ti samples were fabricated by powder metallurgy technique using three kinds of Ti powder and the space holder of polymethyl methacrylate. The final morphological features and mechanical properties were described. Results show that there is only α-Ti phase in porous Ti samples. After sintering, the oxygen content of three porous Ti is increased from the range of 0.34-0.63 wt% to 0.95-1.3 wt%. The porous Ti prepared from the uneven powders with an average particle size of （22.75 ±11.09） μm presents the largest micro-pore size, grain size, and oxygen content, which lead to the lowest strength and Young＇s modulus.
基金financially supported by the National Natural Science Foundation of China(Nos.51971047 and 52271022)the Project of Liaoning Province’s"Rejuvenating Liaoning Talents Plan"(No.XLYC1907046)+2 种基金Dalian High-Level Talent Innovation Support Program(No.2020RJ07)the State Key Lab of Advanced Metals and Materials(No.2021-ZD10)the Joint Research Fund Liaoning-Shenyang National Laboratory for Materials Science(No.2019JH3/30100032)。
文摘Oxygen evolution reaction(OER)plays a crucial role in regulating the process of hydrogen production from water splitting where an expeditious,stable and low-cost electrocatalyst is urgently required.By employing a facile strategy of selective phase dissolution,this dissertation attempts to illuminate the successful preparation of a porous AlCoCrFeNi high-entropy alloy(SPD-48 h).
文摘为精确刻画匝道合流区客货混行条件下的车辆微观换道行为,本文以量化客货交互为切入点,构建并验证考虑货车影响的微观换道模型。首先,引入“压迫”概念,构建改进Morse势函数模型描述周边货车行驶对小汽车横纵驾驶行为产生的“压迫”影响;随后,分析小汽车换道过程中的横纵向“压迫”变化,提出一种考虑货车“压迫”影响的车辆换道决策模型(Modified Morse-Based Lane-Changing model,MMBLC);最后,基于实测轨迹数据进行数值仿真,验证模型的稳定性与有效性,并进一步利用Python与SUMO(Simulation of Urban Mobility)联合仿真,对比MMBLC模型和现有换道模型在交通流中的表现。结果表明:在稳定性分析中,MMBLC模型对交通流的影响更小,恢复稳定的速度更快;在货车占比30%和交通量3600 veh·h-1的主路3车道客货混行匝道合流区中,MMBLC模型相比LC2013和MOBIL(Model of Optimal Control Based on Interacting Trajectories)模型,换道成功率分别提高11.9%和53.1%,危险场景占比分别降低10.5%和52.8%。
基金financial support from the National Natural Science Foundation of China(Nos.21771071,22171094,21925104,and 92261204)the Hubei Provincial Natural Science Foundation of China(No.2021CFA020)。
文摘In core-shell silver nanoclusters,the control of core structure presents a more formidable challenge compared to that of the shell structure.Here,we report the successful synthesis and characterization of four distinct silver thiolate nanoclusters[MS_(4)@Ag_(12)@Ag_(46)S_(24)(dppb)_(12)](M=Mo or W),each incorporating a cup-like[MS_(4)@Ag_(12)]^(2+)kernel.These nanoclusters were meticulously prepared using(NH_(4))2Mo S4or(NH_(4))_(2)WS_(4)as both a template and a controlled source of S2-ions.Remarkably,we have observed a unique configuration within these eight-electron superatomic Ag_(58) nanoclusters,where the zerovalent Ag atoms reside exclusively within the inner[MS_(4)@Ag_(12)]^(2+)kernel.This stands in contrast to other superatomic clusters possessing an Ag(0)core.Notably,the introduction of phenyl-containing compounds during the synthesis process induced a transformation in the space group symmetry from C_(2)/c to I 4ˉ.This transformative effect was found to originate from the interplay between adjacent 1,4-bis(diphenylphosphino)butane(dppb)ligands,which facilitated enhanced emission through aggregationinduced intermolecular interactions,specifically C-H···πinteractions.Collectively,our findings contribute substantively to the understanding of the intricate relationship between nanocluster structures and their corresponding properties,shedding light on the crucial roles played by templates and diphosphine ligands in this context.
基金Project (No. U1233201) supported by the Joint Funds of National Science Foundation of ChinaCivil Administration Foundation of China
文摘Journal misalignment is common in journal bearings. When severe journal misalignment takes place, it affects nearly all aspects of bearing performance. This paper provided a comprehensive analysis of misaligned journal bearings based on two different mass-conservative models which appropriately took into account film rupture and reformation. The lubrication characteristics and performance parameters including the cavitation zones, pressure distribution, density distribution, oil leakage, load capacity, moment, and attitude angle were compared with the traditional lubrication model. The results showed that cavitation has great effect on bearing performances, especially when the surface roughness is large. Therefore, it is necessary to consider the effects of journal misalignment alongside inter-asperity cavitation theory in the design and analyses of journal bearings.
文摘高速公路客货混行场景下,客货车辆物理性能和驾驶行为差异易导致货车后方小汽车出现急加减速、超车等危险驾驶行为,影响交通流稳定性,加剧道路交通事故风险。鉴于此,聚焦于客货场景,创新性地以货车“压迫度”为切入点,探究客货车辆交互影响下小汽车的换道行为和行车风险。首先,引入分子相互作用力构建考虑驾驶风格的货车压迫度(Oppression Measurement of Truck,OMT)量化指标,以量化货车对小汽车行驶存在的压迫影响。进一步采用货车压迫度优化小汽车换道意图判别方法,并融合货车压迫度构建基于卷积神经网络-长短期记忆混合神经网络(CNN-LSTM)的换道意图识别模型和基于轻量级梯度提升机(LightGBM)的换道风险预测模型联合组成的两阶段换道风险预测模型,并采用车辆轨迹数据集验证模型的有效性。研究结果表明:有换道行为的车辆总体上受到更强烈的货车压迫;熟练型驾驶人能够容忍高强度的货车压迫,而谨慎型的驾驶人对货车压迫较为敏感,偏向于保持在低压迫度下行驶。其次,货车压迫度与行车冲突之间存在时间滞后相关效应,较强压迫度能影响车辆驾驶行为,进而引发行车风险变化。融合了货车压迫度指标的模型在换道意图识别与风险预测中表现出更高的精度,并且货车压迫度在换道风险预测模型中具有较高的特征贡献度,研究结果可为复杂交互场景的微观建模与主动安全管控提供全新视角和有效理论支撑。
