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Evolution of mechanical states in new prefabricated slab track during self-compacting concrete casting: A full-scale experimental and numerical study

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Construction and Building Materials 2025年 482卷

作者： Wang, Ludong Chen, Xiangsheng Zhong, Yanglong Gao, Liang Wang, Ji Shi, Shunwei Wang, Chunyu Zhang, Shuang Frontiers Science Center for Smart High-speed Railway System Beijing Jiaotong University Beijing China State Key Laboratory of Advanced Rail Autonomous Operation Beijing Jiaotong University Beijing China School of Civil Engineering Beijing Jiaotong University Beijing China College of Civil and Transportation Engineering Shenzhen University Shenzhen China Railway Engineering Research Institution China Academy of Railway Sciences Corporation Limited Beijing China

The quality of self-compacting concrete (SCC) on-site casting directly affects the smoothness of the new prefabricated slab track (NPST), which significantly influences high-speed train operations. Therefore, this study investigated the influence of SCC flow state on the mechanical state evolution of the track slab and explored the optimization of key construction parameters. Firstly, a high-precision monitoring method was designed to measure the dynamic flow characteristics of SCC and the macroscopic mechanical state of the track structure. Secondly, a fluid-structure interaction (FSI) analysis model for the SCC casting process was established, with fresh SCC constitutive parameters obtained experimentally to analyze the microscopic mechanical responses of track slab. Finally, key construction parameters were optimized. The results indicate that the flow characteristics of SCC cause central arching of the track slab in the later stages of casting construction, with a positive correlation between the upward velocity of SCC in the anti-overflow tube and the growth rate of buoyant force. Additionally, fresh SCC casting process should be completed within 60 min after the SCC raw mixing. It is also recommended to set the anti-overflow tube height to 15–25 cm and design the clamping device stiffness within 210.0–262.5 GPa. This study provides technical reference for NPST development and insights for standardizing ballastless track construction. © 2025 Elsevier Ltd

关键词： Weldability

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Noise Reduction of UAV Using Biomimetic Propellers with Varied Morphologies Leading-edge Serration

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Journal of Bionic Engineering 2020年第4期17卷 767-779页

作者： Yuliang Wei Feng Xu Shiyuan Bian Deyi Kong State Key Laboratory of Transducer Technology Key Laboratory of Biomimetic Sensing and Advanced Robot Technology of Anhui ProvinceInstitute of Intelligent MachinesChinese Academy of SciencesHefei 230031China Science Island Branch of Graduate School University of Science and Technology of ChinaHefei 230009China

The Leading-Edge(LE)serrations on owls'wings are known to be responsible for silent ***,this design has rarely been applied to reduce the noise of rotational rotor propellers and the morphologies of the existing serration designs are ***,we present a comparative study ofLE serrations with different morphologies in terms of the effectiveness in suppressing noise and promoting thrust *** performances of biomimetic propellers are investigated by Computational Fluid Dynamics(CFD)simulations and rotation *** simulation results reveal that LE serrations could reduce velocity fluctuations and change the lamina-turbulent transition and turbulence distribution on the suction surface of propeller,but the morphology of the serrations influences its *** testing results indicate that the sawtooth propeller has the best performance on noise reduction(on average 2.43 dB and in maximum 4.18 dB)and simultaneously enhancing the thrust forces(3.53%).The largest practical noise reductions(4.73 dB and 3.79 rdB)using the sawtooth propeller are observed when the quad-rotor Unmanned-Aerial Vehicle(UAV)is hovering at heights of 5 m and 8 m,*** results indicate the robustness and usefulness of owl-inspired biomimetic serration devices for aero-acoustic control and aerodynamic performance promotion on propeller *** finding is expected to con^bute to suppressing the sound of propeller and the rotor-based aircraft.

关键词： unmanned-aerial vehicle biomimetic noise reduction LE serration rotor propeller

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Excavator Energy-saving Efficiency Based on Diesel Engine Cylinder Deactivation Technology

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Chinese Journal of Mechanical Engineering 2012年第5期25卷 897-904页

作者： YANG Jing QUAN Long YANG Yang Key Laboratory of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan University of Technology Taiyuan 030024 China The State Key Lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 31002 7 China

The hydraulic excavator energy-saving research mainly embodies the following three measures： to improve the performance of diesel engine and hydraulic component, to improve the hydraulic system, and to improve the power matching of diesel-hydraulic system-actuator. Although the above measures have certain energy-saving effect, but because the hydraulic excavator load changes frequently and fluctuates dramatically, so the diesel engine often works in high-speed and light load condition, and the fuel consumption is higher. Therefore, in order to improve the economy of diesel engine in light load, and reduce the fuel consumption of hydraulic excavator, energy management concept is proposed based on diesel engine cylinder deactivation technology. By comparing the universal characteristic under diesel normal and deactivated cylinder condition, the mechanism that fuel consumption can be reduced significantly by adopting cylinder deactivation technology under part of loads condition can be clarified. The simulation models for hydraulic system and diesel engine are established by using AMESim software, and fuel combustion consumption by using cylinder-deactivation-technology is studied through digital simulation approach. In this way, the zone of cylinder deactivation is specified. The testing system for the excavator with this technology is set up based on simulated results, and the results show that the diesel engine can still work at high efficiency with part of loads after adopting this technology; fuel consumption is dropped down to 11% and 13% under economic and heavy-load mode respectively under the condition of driving requirements. The research provides references to the energy-saving study of the hydraulic excavators.

关键词： diesel engine cylinder deactivation hydraulic excavator energy-saving

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10 λ ×3.26Tb/s CPRI-Equivalent Rate 1024-QAM DA-RoF Fronthaul in Single-Mode Fiber Using Coherent-Compliant DSP

10 λ ×3.26Tb/s CPRI-Equivalent Rate 1024-QAM DA-RoF Fronth...

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2023 Asia Communications and Photonics Conference/2023 International Photonics and Optoelectronics Meetings, ACP/POEM 2023

作者： Zhu, Yixiao Fang, Xiansong Zhang, Chenbo Zhou, Lingjun Zheng, Jiayu Xu, Yicheng Xie, Xiaopeng Zhang, Fan Zhuge, Qunbi Hu, Weisheng Shanghai Jiao Tong University State Key Laboratory of Advanced Optical Communication System and Networks Shanghai China Peking University State Key Laboratory of Advanced Optical Communication System and Networks Beijing China

We experimentally demonstrate high-capacity coherent DA-RoF fronthaul leveraging pilot symbol- and BPS-based carrier phase recovery. Up to 4.42- This and 32.6- This CPRI-equivalent rates are achieved with single-carri... 详细信息

ISBN: (纸本)9798350312614

关键词： carrier phase recovery coherent detection CPRI fronthaul radio-over-fiber

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Towards silicon photonic neural networks for artificial intelligence

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Science China(Information Sciences) 2020年第6期63卷 105-118页

作者： Bowen BAI Haowen SHU Xingjun WANG Weiwen ZOU State Key Laboratory of Advanced Optical Communications System and Networks School of Electronics Engineering and Computer Science Peking University Frontiers Science Center for Nano-optoelectronics Peking University State Key Laboratory of Advanced Optical Communication Systems and Networks Intelligent Microwave Lightwave Integration Innovation Center(iMLic) Department of Electronic Engineering Shanghai Jiao Tong University

Brain-inspired photonic neural networks for artificial intelligence have attracted renewed interest. For many computational tasks, such as image recognition, speech processing and deep learning, photonic neural networks have the potential to increase the computing speed and energy efficiency on the orders of magnitude compared with digital electronics. Silicon Photonics, which combines the advantages of electronics and photonics, brings hope for the large-scale photonic neural network integration. This paper walks through the basic concept of artificial neural networks and focuses on the key devices which construct the silicon photonic neuromorphic systems. We review some recent important progress in silicon photonic neural networks, which include multilayer artificial neural networks and brain-like neuromorphic systems, for artificial intelligence. A prototype of silicon photonic artificial intelligence processor for ultra-fast neural network computing is also proposed. We hope this paper gives a detailed overview and a deeper understanding of this emerging field.

关键词： photonic neural networks artificial intelligence deep learning photonic computing accelerator silicon photonics

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1-Pb/s CPRI-Equivalent Rate Coherent DA-RoF Fronthaul with 1024-QAM Scalable in Capacity, Reach, and Linewidth Using Residual Carrier-Based Phase Tracking

1-Pb/s CPRI-Equivalent Rate Coherent DA-RoF Fronthaul with 1...

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2023 Asia Communications and Photonics Conference/2023 International Photonics and Optoelectronics Meetings, ACP/POEM 2023

作者： Zhu, Yixiao Fang, Xiansong Zhang, Chenbo Lin, Jingjing Xu, Yicheng Hu, Weiwei Chen, Zhangyuan Zhuge, Qunbi Zhang, Fan Xie, Xiaopeng Hu, Weisheng Shanghai Jiao Tong University State Key Laboratory of Advanced Optical Communication System and Networks Shanghai China Peking University State Key Laboratory of Advanced Optical Communication System and Networks Beijing China

ISBN: (纸本)9798350312614

We demonstrate 1.0-Pb/s CPRI-equivalent rate fronthaul with 1024-QAM by using digital-analog radio-over-fiber and coherent detection based on modulator bias-induced residual carrier for phase tracking. The reach is extended to 20-km SSMF with 4096-QAM and 80-km with 256-QAM, and laser linewidth can be relaxed to 3MHz. © 2023 IEEE.

关键词： carrier phase recovery coherent detection CPRI fronthaul radio-over-fiber

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Computational homogenization of thermomechanical properties for Fully Ceramic Microencapsulated fuel with 3D printed SiC matrix

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Annals of Nuclear Energy 2025年 222卷

作者： Yiwen Chen Qi Lu Changwen Liu Wei Li Dalin Zhang G.H. Su State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an 710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 61213 China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong University Xi’an 710049 China

Fully Ceramic Microencapsulated (FCM) fuel, fabricated using 3D printing technology, incorporates traditional Tristructural-Isotropic (TRISO) fuel particles embedded within a 3D-printed SiC matrix. This fuel type shows great potential for compact, high-temperature nuclear reactors. However, comprehensive performance analysis remains challenging due to the multilayered structure, complex material properties, and the irradiation behavior of numerous TRISO particles within the matrix. To address these challenges, this study aims to apply finite element (FE)-based computational homogenization to evaluate the fuel’s thermomechanical properties. First, a detailed finite element analysis (FEA) of a single TRISO particle’s performance was conducted, focusing primarily on the Buffer-IPyC gap size change during irradiation, a critical factor influencing the fuel’s thermal performance. Second, the homogenization of a single TRISO particle was performed using FEA, accounting for the changes in the Buffer-IPyC gap size. Finally, homogenized TRISO particles were randomly distributed and perfectly bonded within a 3D-printed SiC matrix to form a Representative Volume Element (RVE). The FE homogenization of the RVE was then conducted to derive the effective thermomechanical properties of the FCM fuel. The packing fraction of TRISO particles in the matrix ranged from 10 % to 50 %, with temperature and burnup conditions spanning 800–1600 K and 0–16 % FIMA, respectively. Results show that irradiation significantly affects the effective properties of the fuel, though this impact diminishes as burnup increases. Additionally, the effective thermal conductivity of the FCM fuel decreases with increasing TRISO packing fraction, assuming the thermal conductivity of the SiC matrix exceeds that of TRISO particles. This study provides a valuable reference for the design and optimization of FCM fuel for future nuclear applications.

关键词： Thermal conductivity of solids

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High-Capacity Digital-Analog Fronthaul via Self-Homo Dyne Detection

High-Capacity Digital-Analog Fronthaul via Self-Homo Dyne De...

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2023 Asia Communications and Photonics Conference/2023 International Photonics and Optoelectronics Meetings, ACP/POEM 2023

作者： Zhu, Yixiao Zhang, Chenbo Xu, Yicheng Zhuge, Qunbi Xie, Xiaopeng Hu, Wei Sheng Shanghai Jiao Tong University State Key Laboratory of Advanced Optical Communication System and Networks Shanghai China Peking University State Key Laboratory of Advanced Optical Communication System and Networks Beijing China

We overview the recent progress of high-capacity mobile fronthaul based on digital-analog radio-over-fiber and self-homodyne coherent detection. The principle, architecture, and perspectives are discussed. © 2023... 详细信息

ISBN: (纸本)9798350312614

关键词： CPRI-equivalent rate mobile fronthaul radio-over-fiber self-homodyne coherent detection

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Dynamical Behavior of an Atomic Beam Interacting with a Fock state Light Field

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Chinese Physics Letters 2010年第1期27卷 100-103页

作者：李犇陈景标 Institute of Quantum Electronics and State Key Laboratory of Advanced Optical Communication System & Network School of Electronics Engineering & Computer Science Peking University Beijing 100871

The collapse and revival of evolution with photon number of population inversion in the case of an atomic beam with velocity distribution interacting with a single-mode and Fock-state light field is investigated by full quantum theory. Compared to the previously reported coherent state case [Li B and Chen J B Chin. Phys. Lett. 26（2009）123203], which was induced by evolution with coupling strength of population inversion, in the case under consideration there exists Poisson distribution of photon numbers and atomic velocity distribution in the beam. Moreover, we prove that above, the collapse and revival have an analogy with conventional collapse and revival [Eberly J H et al. Phys. Rev. Lett. 44（1980）1323] in both the mathematical expression and physical significance.

关键词： Chinese climate network complex systems small world community

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Kinematics and Dynamics Analysis of a Quadruped Walking robot with Parallel Leg Mechanism

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Chinese Journal of Mechanical Engineering 2013年第5期26卷 881-891页

作者： WANG Hongbo SANG Lingfeng HU Xing ZHANG Dianfan YU Hongnian Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Xi’an University of Architecture and Technology Science and Technology Research Institute Yanshan University School of Design Engineering and ComputingBournemouth University

It is desired to require a walking robot for the elderly and the disabled to have large capacity,high stiffness,stability,***,the existing walking robots cannot achieve these requirements because of the weight-payload ratio and simple ***,Improvement of enhancing capacity and functions of the walking robot is an important research *** to walking requirements and combining modularization and reconfigurable ideas,a quadruped/biped reconfigurable walking robot with parallel leg mechanism is *** proposed robot can be used for both a biped and a quadruped walking *** kinematics and performance analysis of a 3-UPU parallel mechanism which is the basic leg mechanism of a quadruped walking robot are conducted and the structural parameters are *** results show that performance of the walking robot is optimal when the circumradius R,r of the upper and lower platform of leg mechanism are 161.7 mm,57.7 mm,*** on the optimal results,the kinematics and dynamics of the quadruped walking robot in the static walking mode are derived with the application of parallel mechanism and influence coefficient theory,and the optimal coordination distribution of the dynamic load for the quadruped walking robot with over-determinate inputs is analyzed,which solves dynamic load coupling caused by the branches’ constraint of the robot in the walk *** laying a theoretical foundation for development of the prototype,the kinematics and dynamics studies on the quadruped walking robot also boost the theoretical research of the quadruped walking and the practical applications of parallel mechanism.

关键词： walking robot parallel leg mechanism kinematics dynamics over-determinate inputs

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