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Quantitative characterization of fusion state of virgin and aged asphalt using nano-ferrous ferric oxide tracer

Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 467-480页

作者： Qiang Li Song Liu Huameng Wen zhou zhou College of Civil Engineering Nanjing Forestry UniversityNanjing 210037China School of Transportation Southeast UniversityNanjing 211189China

The exact evaluation of the fusion rate of virgin and aged asphalt is essential to optimize the performance of the recycled asphalt *** fusion rate index was developed by tracing the distribution of tracer asphalt,which contains nano-ferrous ferric oxide(nano-Fe_(3)O_(4))*** fusion simulation tests were performed on three types of asphalt to obtain different fusion states,and fatigue tests were performed to evaluate the influence of the fusion rate on the fatigue life of the recycled *** was found that the tracer asphalt containing 4%nano-Fe_(3)O_(4)shows the optimal trace effect,and the developed fusion rate index can quantitatively characterize the influence of different factors on the fusion state of the recycled *** fusion state is closely related to the fatigue performance of recycled asphalt,and the fusion rate index can fairly evaluate its fatigue *** relationship between the fusion rate and the fatigue life of recycled asphalt depends on the factors that cause the fusion rate *** the influence of the amount of rejuvenator,the fatigue life of recycled asphalt grows exponentially with increasing fusion rate due to enhancement of molecular motion as well as a supplement of lightweight *** the influence of heat preservation treatment,fatigue life increases linearly with increasing fusion *** proposed fusion rate index can be utilized to quantitatively characterize the fusion state of virgin and aged asphalt,thus providing a simple way to guide the practical application of recycled asphalt.

关键词： Recycled asphalt Rejuvenator Tracing technique Fusion rate Fatigue

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Construction Activity Analysis of Workers Based on Human Posture Estimation Information

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Engineering 2024年第2期33卷 225-236页

作者： Xuhong zhou Shuai Li Jiepeng Liu zhou Wu Yohchia Frank Chen School of Civil Engineering Chongqing UniversityChongqing 400044China School of Automation Chongqing UniversityChongqing 400044China Department of Civil Engineering The Pennsylvania State UniversityMiddletownPA 17057USA

Identifying workers’construction activities or behaviors can enable managers to better monitor labor efficiency and construction ***,current activity analysis methods for construction workers rely solely on manual observations and recordings,which consumes considerable time and has high labor *** have focused on monitoring on-site construction activities of ***,when multiple workers are working together,current research cannot accu rately and automatically identify the construction *** research proposes a deep learning framework for the automated analysis of the construction activities of multiple *** this framework,multiple deep neural network models are designed and used to complete worker key point extraction,worker tracking,and worker construction activity *** designed framework was tested at an actual construction site,and activity recognition for multiple workers was performed,indicating the feasibility of the framework for the automated monitoring of work efficiency.

关键词： Pose estimation Activity analysis Object tracking Construction workers Automatic systems

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Energy-information trade-off induces continuous and discontinuous phase transitions in lateral predictive coding

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 79-85页

作者： Zhen-Ye Huang Ruyi zhou Miao Huang Hai-Jun zhou Key Laboratory for Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China Minjiang Collaborative Center for Theoretical Physics Minjiang UniversityFuzhou 350108China

Lateral predictive coding is a recurrent neural network that creates energy-efficient internal representations by exploiting statistical regularity in sensory ***,we analytically investigate the trade-off between information robustness and energy in a linear model of lateral predictive coding and numerically minimize a free energy *** observed several phase transitions in the synaptic weight matrix,particularly a continuous transition that breaks reciprocity and permutation symmetry and builds cyclic dominance and a discontinuous transition with the associated sudden emergence of tight balance between excitatory and inhibitory *** optimal network follows an ideal gas law over an extended temperature range and saturates the efficiency upper bound of energy *** results provide theoretical insights into the emergence and evolution of complex internal models in predictive processing systems.

关键词： predictive coding recurrent neural network phase transition internal model free energy

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General properties of the spectral form factor in open quantum systems

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Frontiers of physics 2024年第3期19卷 229-237页

作者： Yi-Neng zhou Tian-Gang zhou Pengfei Zhang Institute for Advanced Study Tsinghua UniversityBeijing 100084China Department of Physics Fudan UniversityShanghai 200438China

The spectral form factor(SFF)can probe the eigenvalue statistic at different energy scales as its time variable *** closed quantum chaotic systems,the SFF exhibits a universal dip-ramp-plateau behavior,which reflects the spectrum rigidity of the *** this work,we explore the general properties of SFF in open quantum *** find that in open systems the SFF first decays exponentially,followed by a linear increase at some intermediate time scale,and finally decreases to a saturated plateau *** derive general relations between(i)the early-time decay exponent and Lindblad operators;(ii)the long-time plateau value and the number of steady *** also explain the effective field theory perspective of general *** verify our theoretical predictions by numerically simulating the Sachdev−Ye−Kitaev(SYK)model,random matrix theory(RMT),and the Bose−Hubbard model.

关键词： spectral form factor open quantum system quantum chaos

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Manipulating submolecular-scale phototautomerization

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Science China Materials 2024年第6期67卷 2048-2050页

作者： Ping zhou Hongliang Chen Stoddart Institute of Molecular Science Department of ChemistryZhejiang UniversityHangzhou 310058China Zhejiang-Israel Joint Laboratory of Self-Assembling Functional Materials ZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang UniversityHangzhou 311215China

A recent study on the submolecular-scale control of phototautomerization methods and the underlying reaction mechanisms was reported in Nature Nanotechnology by Guillaume and co-workers[1],elucidating how the field confinement effect generated by the scanning tunneling microscope(STM)tip precisely triggers the phototautomerization of a free-base phthalocyanine at the submolecular level and demonstrating that the reaction process can be finely controlled by adjusting either the laser excitation wavelength or the position of the tip.

关键词： tunneling excitation phthalocyanine

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Origin and tectonic setting of low-Si alkaline magma

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Science China Earth Sciences 2024年第5期67卷 1417-1435页

作者： Qiushi zhou Rui WANG State Key Laboratory of Geological Processes and Mineral Resources and Institute of Earth SciencesChina University of GeosciencesBeijing 100083China Frontiers Science Center for Deep-time Digital Earth China University of Geosciences(Beijing)Beijing 100083China

Despite of the relatively rare occurrence of alkaline igneous rocks on Earth, they are the most diverse group of igneous rocks due to variations in their mineral assemblages and geochemical compositions. Alkaline igneous rocks are generally characterized by Si undersaturation, and K-Na(and in some cases C) enrichment. Although there is no unified alkaline igneous rock classification scheme, diagrams such as total alkalis-SiO_(2) or K_(2)O-SiO_(2) can be used to classify alkaline igneous rocks. The origins of silica-saturated alkaline rocks(SiO_(2)>52 wt.%) are relatively complex because multiple episodes of magmatism are often involved, therefore most studies have focused on the origins of silica-undersaturated alkaline *** experimental petrological studies have been conducted in the past few decades. Initially, it was considered that enrichment of trace elements was only achieved by low-degree partial melting of mantle peridotite, but the experimental melts could not reproduce the geochemical composition of natural alkaline igneous rocks. Subsequent studies have focused on carbonate-bearing eclogites that represent the average component of subducted oceanic crust. Although experimental studies indicate that silica-undersaturated and alkali-oversaturated melts can be generated from eclogites, some studies have considered that natural silica-undersaturated alkaline igneous rocks are the result of multi-stage source enrichment by incompatible elements. Low-degree partial melts of the mantle can be emplaced in the lithospheric mantle, forming veins consisting of phlogopite, amphibole, and pyroxene. Melting experiments including these components show that the produced melts better reproduce the naturally occurring silica-undersaturated alkaline magmas. Silica-deficient alkaline igneous rocks occur in various tectonic settings. Those in intraplate and divergent settings(i.e., mainly continental rifts) normally involve contributions from recycled components su

关键词： Alkaline igneous rock Tectonic setting Petrogenesis Big data

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晶界添加Ho_(63.3)Fe_(36.7)对NdFeB再生磁体组织与性能的影响

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稀有金属材料与工程 2021年第12期50卷 4230-4235页

作者：孙前程姚青荣龙乾新黄伟超邓健秋王江饶光辉周怀营桂林电子科技大学材料科学与工程学院广西信息材料重点实验室广西桂林541004 中国稀土(广西)金源新材料有限公司广西贺州542603

采用一种高效、绿色的物理方法对NdFeB废旧磁体表面进行清理并回收利用。通过晶界添加低熔点Ho_(63.3)Fe_(36.7)合金制备NdFeB再生磁体。在未添加Ho_(63.3)Fe_(36.7)的磁体中,没有足够的富Nd相隔离Nd_(2)Fe_(14)B相,从而导致磁体性能较... 详细信息

采用一种高效、绿色的物理方法对NdFeB废旧磁体表面进行清理并回收利用。通过晶界添加低熔点Ho_(63.3)Fe_(36.7)合金制备NdFeB再生磁体。在未添加Ho_(63.3)Fe_(36.7)的磁体中,没有足够的富Nd相隔离Nd_(2)Fe_(14)B相,从而导致磁体性能较差;随着Ho_(63.3)Fe_(36.7)合金的加入,晶界相变得清晰且连续。在质量分数2%Ho_(63.3)Fe_(36.7)添加量下,钕铁硼再生磁体获得最佳磁性能[(BH)_(max)+H_(cj)=1756.07]。此时矫顽力增加123 kA/m(约提高9.1%),磁体的最大能积由290.94 kJ/m^(3)下降到281.07 kJ/m^(3),而剩磁少量下降。通过对再生磁体显微组织和成分的分析可知,磁体晶界处形成了(Nd,Pr,Ho)_(2)Fe_(14)B壳层,这能够提高磁体的矫顽力。而X射线衍射分析表明,磁体I_((006))/I_((105))的衍射峰强度比从0.92提高到1.32。这说明磁体取向度提高,可以减弱对剩磁的影响,从而使得再生磁体在保持剩磁的同时提高磁体的矫顽力。

关键词： NdFeB再生磁体磁性能晶界添加取向度

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Revealing the Void Formation Mechanism during Superplastic Deformation of a Fine-Grained Ni-Co-Base Superalloy

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 915-920页

作者： Rashad AAl-Hammadi Rui Zhang Chuanyong Cui Zijian zhou Yizhou zhou Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

The mechanism behind void formation during superplasticity remains a subject of *** study presented a novel insight into the void formation in a fine-grained Ni-Co-based superalloy during *** was observed that the dissolution ofγ′-particles resulted in the creation of vacancies due to differences in atomic size between the matrix and the *** vacancies acted as inclusions,leading to the formation of ***,excessive void formation correlated with higher particle dissolution was experimentally observed,highlighting a direct relationship between void formation and particle dissolution.

关键词： Superplasticity Void formation Ni-Co-based superalloy Microstructure

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宽温型AB_5储氢合金结构及其电化学性能研究

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稀有金属 2012年第2期36卷 229-235页

作者：倪成员周怀营王仲民欧气局马宇飞中南大学材料科学与工程学院湖南长沙410012 桂林电子科技大学材料科学与工程学院广西桂林541004

用高频感应熔炼法制备了Mm(NiCoAlMn)5储氢合金,采用模拟电池法测试了合金在238～323 K温度范围内的活化、放电容量和高倍率放电性能。结果表明:制备合金为典型AB5型储氢合金,303 K温度条件下吸氢量达到1.38%(质量分数),氢化物生成焓为3... 详细信息

用高频感应熔炼法制备了Mm(NiCoAlMn)5储氢合金,采用模拟电池法测试了合金在238～323 K温度范围内的活化、放电容量和高倍率放电性能。结果表明:制备合金为典型AB5型储氢合金,303 K温度条件下吸氢量达到1.38%(质量分数),氢化物生成焓为32.36 ***-1H2。合金电极的活化性能、放电容量和高倍率性能受温度影响显著。室温预活化可有效改善电极的低温性能,经室温预活化后合金电极在238 K最大放电容量达到336 mAh.g-1,明显高于未经室温预活化的最大放电容量25 mAh.g-1。Mm(NiCoMn)5贮氢合金电极的高倍率性能随着温度的升高先升高后降低,273和303 K温度条件下合金保持高倍率性能良好,3C放电电流密度条件下容量保持率均高于80%;238 K温度条件下合金的大电流放电性能急剧降低,1C放电电流密度条件下容量保持率仅为10%;273 K下合金电极的综合性能最佳,最大放电容量达到340 mAh.g-1,300 mA.g-1放电电流密度下的高倍率放电比率为86%。循环伏安法测试证实,在238～323 K范围内,电极的氧化峰峰值电流(IP)与扫描速度的平方根(ν1/2)之间均存在良好的线性关系,整个电极反应受氢原子扩散控制;随着温度的降低氢扩散系数急剧下降,从而导致该合金电极的低温高倍率放电性能变差。由Arrhenius公式计算出合金中的氢扩散活化能为10.56 ***-1。

关键词： Mm(NiCoAlMn)5 合金电极温度电化学性能高倍率放电

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Adaptive state-constrained/model-free iterative sliding mode control for aerial robot trajectory tracking

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 603-618页

作者： Chen AN Jiaxi zhou Kai WANG College of Mechanical and Vehicle Engineering Hunan UniversityChangsha 410082China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHong KongChina

This paper develops a novel hierarchical control strategy for improving the trajectory tracking capability of aerial robots under parameter *** hierarchical control strategy is composed of an adaptive sliding mode controller and a model-free iterative sliding mode controller(MFISMC).A position controller is designed based on adaptive sliding mode control(SMC)to safely drive the aerial robot and ensure fast state convergence under external ***,the MFISMC acts as an attitude controller to estimate the unmodeled dynamics without detailed knowledge of aerial ***,the adaption laws are derived with the Lyapunov theory to guarantee the asymptotic tracking of the system ***,to demonstrate the performance and robustness of the proposed control strategy,numerical simulations are carried out,which are also compared with other conventional strategies,such as proportional-integralderivative(PID),backstepping(BS),and *** simulation results indicate that the proposed hierarchical control strategy can fulfill zero steady-state error and achieve faster convergence compared with conventional strategies.

关键词： aerial robot hierarchical control strategy model-free iterative sliding mode controller(MFISMC) trajectory tracking reinforcement learning

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