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Excellent dynamic yield and spall strength of single crystal NiAlCo alloy under shock compression

Materials science and Engineering: A 2025年 939卷

作者： Pan, X.T. Dong, J.L. Chen, X.M. Luo, B.Q. Shui, R.J. Xu, C. Wu, G. Wang, G.J. Wu, H.A. Tan, F.L. Zhao, J.H. Sun, C.W. CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Hefei230027 China Institute of Fluid Physics China Academy of Engineering Physics Mianyang621999 China Institute of Applied Electronics China Academy of Engineering Physics Mianyang621999 China

A fundamental understanding of the mechanical behaviors and deformation mechanism of materials subjected to dynamic loading is critical for developing outstanding structural materials. This work focuses on the experimental investigation into the dynamic mechanical behaviors, deformation mechanisms, and damage characteristics of single-crystal NiAlCo which was regarded as a potential structure material at high pressure and strain rate. The shock responses of the single-crystal NiAlCo alloy were tested over a range of shock pressure from 10 to 50 GPa at a strain rate of 105/s utilizing the technique of magnetically driven high-velocity flyer plates on high pulsed power generator CQ-4. Based on the analyses of free surface velocity profiles, a linear Hugoniot relationship between shock wave speed and particle velocity was obtained, and the spall strength gradually increased from 2.61 GPa to 6.98 GPa with increasing shock pressure. The yield strength was calculated from the Hugoniot elastic limit, and it reaches 1.80 GPa over the wide range of shock pressure. Further, the relationship between dynamic strength and strain rate was depicted by empirical formulas in power exponential form. Finally, the detailed transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) microscopic characterization results of recovered samples disclose that single-crystal NiAlCo have abundant micro-deformation mechanisms under high pressure and high strain rate, including dislocation tangle, high-density stacking faults, and Lomer-Cottrell locks. The results show that both spall and yield strength are significantly higher than those of most alloys, exhibiting superior mechanical properties, which may be attributed to the coupling of multiple deformation mechanisms. © 2025 Elsevier B.V.

关键词： Strain rate

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Nonstoichiometric Protic Ionic Liquids for Efficient Carbon Dioxide Capture

SSRN

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SSRN 2023年

作者： Wang, Litian Chen, Jie Li, Dan Li, Cuiping Qian, Lirong Xiong, Yang Xie, Zhiyong Wang, Shuai Zhou, Tongyao Gai, Baojia Wang, Yinuo Tianjin Key Laboratory of Film Electronic and Communication Devices School of Integrated Circuit Science and Engineering Tianjin University of Technology Tianjin300384 China School of Integrated Circuit Science and Engineering Tianjin University of Technology Tianjin300384 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China Tianjin Bohua Yongli Chemical Industry CO. Ltd Tianjin30045 China

Protic ionic liquids (PILs) have emerged as promising solvents for CO2 capture, offering great potential for the development of efficient CO2 absorbents. Understanding the relationship between the PILs’ structures and CO2absorption mechanisms is instructive for advancing their applicability. Herein, an innovative strategy for CO2 capture using nonstoichiometric PILs was demonstrated for the first time. These nonstoichiometric PILs composed of imidazole (Im) as a Brønsted acid and 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) as a Brønsted base with various ratios. They exhibited both low viscosities and remarkable CO2 loading capacities, reaching up to 0.194 g CO2 /g IL and 1.42 mol CO2 /mol IL at 0.1 atm and 40 °C. The distribution of neutral and ionic species in these nonstoichiometric PILs was determined using density functional theory (DFT) calculations and nuclear magnetic (NMR) spectroscopy analysis. Correlations between the mole ratio of Brønsted acid and base and the viscosities, conductivities, and CO2 absorption properties were observed. The mechanism of CO2 absorption was proposed from the spectral results and DFT calculations. The superior CO2 loading ability of these PILs can be attributed to the formation of the zwitterionic carbamic complexes through interactions between CO2 and the N atom in DBU. Additionally, the presentence of Im significantly avoided the dramatic increase in the viscosity of the absorbents during CO2 absorption. It is believed that the new insights into the CO2 mechanism will facilitate the rational design of PILs for CO2 capture in the future. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

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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： Chen, Yiwen Lu, Qi Liu, Changwen Li, Wei Zhang, Dalin Su, G.H. 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'an710049 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu61213 China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong University Xi'an710049 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. © 2025 Elsevier Ltd

关键词： Thermal conductivity of solids

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Ultrahigh Thermal Conductance of the Point Contact between Amorphous Nanowire

SSRN

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SSRN 2024年

作者： Wang, Renzong Xiong, Yucheng Yang, Juekuan Liu, Zhichun Li, Shouhang Chen, Ge Liu, Xiangjun Institute of Micro/Nano Electromechanical System College of Mechanical Engineering Donghua University Shanghai201620 China School of Mechanical Engineering Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments Southeast University Nanjing210096 China School of Energy and Power Engineering Huazhong University of Science and Technology Wuhan430074 China

Amorphous interfaces/contacts are ubiquitous in numerous micro/nanoelectronic devices and functional composite materials. Traditionally, the thermal resistance of interfaces/contacts was believed to be the primary impediment to heat transport. However, in this study, through measuring thermal resistance between crystalline-amorphous core-shell Ge nanowires, we unveil an ultrahigh thermal conductance across the point contact between the amorphous shell of Ge nanowires with a room-temperature value of 892 MW/m2-K. This value surpasses the typical values observed in point contacts between crystalline nanowires/nanoribbons by one to three orders of magnitude and even exceeds that of epitaxial interfaces between well-lattice-matched materials. Molecular and lattice dynamic simulations further reveal that the observed ultrahigh thermal conductance is attributed to the broadened vibrational bandwidths within the amorphous contact, which facilitates the redistribution of phonon energy into a state conductive to more effective interfacial energy transmission, leading to an enhanced overlap of phonon modes and, consequently, a heightened thermal conductance. © 2024, The Authors. All rights reserved.

关键词： Heat conduction

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Field-Harmonic-Oriented design of Vernier Permanent Magnet Machine Towards High Torque Density and Low Torque Ripple

Field-Harmonic-Oriented Design of Vernier Permanent Magnet M...

引用

International Conference on Electrical Machines and systems (ICEMS)

作者： Li Fang Dawei Li Yuanzhi Zhang Jiewen Wu School of Electrical and Electronics Engineering Huazhong University of Science and Technology Wuhan China School of Electricla Engineering and Automation (Hubei Key Laboratory of Power Equipment and System Security for Integrated Energy) Wuhan University Wuhan China College of Design and Engineering National University of Singapore Singapore

Vernier permanent magnet machine (VPMM) has been a promising candidate for low-speed large-torque applications owing to high torque density based on multiple-magnetic field-harmonics working principle However, rich field harmonics also cause large torque ripple, meanwhile the regular reducing methods will also undermine torque density. In this paper, the field-harmonic-oriented design approach is proposed for the VPMM towards high torque density and low torque ripple. Based on the permeance unit model, the mapping relationship between torque output and field harmonics is built. Explicit design regulations are established for the airgap structure so as to modulate the optimal field harmonics composition. Via the proposed method, a surface-mounted VPMM is purposely designed and the electromagnetic performance is verified by FEA. Finally, a prototype of the proposed machine has been manufactured and tested. Both analytical and experimental results validate the feasibility of the proposed design method.

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A novel paper-based electrowetting device using cellulose paper and paraffin wax 26

A novel paper-based electrowetting device using cellulose pa...

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26th International Conference on Miniaturized systems for Chemistry and Life sciences, MicroTAS 2022

作者： Li, He Yan, Zhibin Jin, Mingliang Zhou, Guofu Shui, Lingling Guangdong Provincial Key Laboratory of Optical Information Materials and Technology Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics South China Normal University Guangzhou510006 China Defense Key Disciplines Lab of Novel Micro-nano Devices and System Technology Chongqing University Chongqing400044 China School of Information and Optoelectronic Science and Engineering South China Normal University Guangzhou510006 China Guangdong Shunde Innovative Design Institute Guangdong Foshan528318 China

ISBN: (纸本)9781733419048

Paper-based microfluidic devices based on continuous-flow (μPAD) and electrowetting on dielectric (EWOD), have attracted increasing attention due to their low cost and excellent liquid handling capability. Here, we report a novel paper-based EWOD devices fabricated with the cellulose paper as substrate and paraffin wax as dielectric layer, which have been widely used in μPAD. Two methods are proposed to fabricate paraffin wax layer, including melting and spray-coating. Under DC electric field, the spray-coating-based devices show larger contact angle changes but with smaller hysteresis than the melting-based one. Our study opens up a new way for fabrication of the hybrid paper-based microfluidic device in the future. © 2022 MicroTAS 2022 - 26th International Conference on Miniaturized systems for Chemistry and Life sciences. All rights reserved.

关键词： Wetting

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Effects of Wall Emissivity on Aerodynamic Heating in Scramjets

引用

Fluid Dynamics & Materials Processing 2020年第6期16卷 206-216页

作者： Yue Zhou Pengfei Ju School of Aeronautical Science and Technology Beihang UniversityBeijing100191China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education(Tianjin University of Technology) Tianjin300384China

The effects of the wall emissivity on aerodynamic heating in a scramjet are *** supersonic turbulent combustion flow including radiation is solved in the framework of a decoupled strategy where the flow field is determined first and the radiation field *** particular,a finite difference method is used for solving the flow while a DOM(iscrete ordinates method)approach combined with a WSGGM(weighted sum of gray gases)model is implemented for radiative *** nonreactive turbulent channel flows are examined for a DLR hydrogen fueled scramjet changing parametrically the wall *** results indicate that the wall radiative heating rises greatly with increasing the wall *** the wall emissivity rises,the radiative source and total absorption increase,while the incident radiation decreases ***,although the radiative heating can reach a significant level,its contribution to the total aerodynamic heating is relatively limited.

关键词： Scramjet aerodynamic heating wall emissivity radiation

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A Train Cooperative Operation Optimization Method Considering Passenger Comfort based on Reinforcement Learning 11

A Train Cooperative Operation Optimization Method Considerin...

引用

11th IEEE Data Driven Control and Learning systems Conference, DDCLS 2022

作者： Wang, Xingguo Wu, Yue Huang, Deqing Zhu, Lei Lu, Zheng He, Yan Institute of System Science and Technology School of Electrical Engineering Southwest Jiaotong University Chengdu611756 China Southwest Jiaotong University Key Laboratory of Advanced Energy Traction Comprehensive Energy Saving Railway Industry Chengdu610031 China School of Computing and Artificial Intelligence Southwest Jiaotong University Chengdu611756 China School of Design Arts Southwest Jiaotong University Chengdu610031 China

ISBN: (数字)9781665496759

ISBN: (纸本)9781665496759

This paper mainly focuses on the high-speed train cooperative operation problem, considering passenger comfort. To solve this problem, a speed curve optimization method based on Reinforcement Learning algorithm is proposed. First, according to the train dynamics system, we build the speed curve optimization object. For realizing the train cooperative operation and increasing the passenger comfort, trains distance constraint and jerk rate constraint are fully considered in formulating reward function. And then, agent of Twin Delayed Deep Deterministic Policy Gradient (TD3) is established. Based on TD3 algorithm, two groups of Q-value networks and one group of action action networks have the same structure, different initial values and update rates respectively, which improves the stability and convergence speed of the algorithm. After the training. The Agent can generate a desirable speed curve of train based on constraints of vehicle output and jerk rate under cooperative operation. © 2022 IEEE.

关键词： Speed

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Link Budget Calculation for LoRa-band Remoting Sensing Satellite

Link Budget Calculation for LoRa-band Remoting Sensing Satel...

引用

IEEE International Symposium on Electromagnetic Compatibility (EMC-Beijing)

作者： Shurui Wang Xiang Zhang Xiaojun Hao Shuaige Gong Chong Li Qian Xu Lei Xing College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Nanjing China College of Mechanical Engineering (Aircraft design and engineering) Nanjing University of Science and Technology Nanjing China State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System (CEMEE) Luoyang China

Small satellites are increasingly attracting the attention of the industry for its many aspects of advantages. We proposed a communication subsystem for commercial remote sensing satellite. The interface between the communication system and other modules on the satellite and the communication protocol are briefly introduced. In order to make sure that the satellite-to-ground link is reliable, we calculate the link budget at 471 MHz for LEO small satellite. Additionally, the transmission power and reception sensitivity is 17 dBm and −123 dBm respectively. The result shows that the proposed subsystem is reliable in RF performance and can be used in other commercial satellite in the future.

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Reshaping the ISAC Tradeoff Under OFDM Signaling: A Probabilistic Constellation Shaping Approach

arXiv

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arXiv 2023年

作者： Du, Zhen Liu, Fan Xiong, Yifeng Han, Tony Xiao Eldar, Yonina C. Jin, Shi The School of Electronic and Information Engineering Nanjing University of Information Science and Technology Nanjing China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China The School of Information and Electronic Engineering Beijing University of Posts and Telecommunications Beijing China Huawei Technologies Co. Ltd Shenzhen China The Faculty of Mathematics and Computer Science Weizmann Institute of Science Rehovot Israel National Mobile Communications Research Laboratory Southeast University Nanjing210096 China

Integrated sensing and communications is regarded as a key enabling technology in the sixth generation networks, where a unified waveform, such as orthogonal frequency division multiplexing (OFDM) signal, is adopted to facilitate both sensing and communications (S&C). However, the random communication data embedded in the OFDM signal results in severe variability in the sidelobes of its ambiguity function (AF), which leads to missed detection of weak targets and false detection of ghost targets, thereby impairing the sensing performance. Therefore, balancing between preserving communication capability (i.e., the randomness) while improving sensing performance remains a challenging task. To cope with this issue, we characterize the random AF of OFDM communication signals, and demonstrate that the AF variance is determined by the fourth-moment of the constellation amplitudes. Subsequently, we propose an optimal probabilistic constellation shaping (PCS) approach by maximizing the achievable information rate (AIR) under the fourth-moment, power and probability constraints, where the optimal input distribution may be numerically specified through a modified Blahut-Arimoto algorithm. To reduce the computational overheads, we further propose a heuristic PCS approach by actively controlling the value of the fourth-moment, without involving the communication metric in the optimization model, despite that the AIR is passively scaled with the variation of the input distribution. Numerical results show that both approaches strike a scalable performance tradeoff between S&C, where the superiority of the PCS-enabled constellations over conventional uniform constellations is also verified. Notably, the heuristic approach achieves very close performance to the optimal counterpart, at a much lower computational complexity. Copyright © 2023, The Authors. All rights reserved.

关键词： Orthogonal frequency division multiplexing

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