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Diagonal-symmetrical and Midline-symmetrical Unit Cells with Same Porosity for Bone Implant: Mechanical Properties Evaluation

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Journal of Bionic Engineering 2019年第3期16卷 468-479页

作者： Jian Li Diansheng Chen Yingying Zhang Yan Yao Zhongjun Mo Lizhen Wang Yubo Fan Robotic Institute Beihang University Beijing 100191 China Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age and Disability and Key Laboratory of Rehabilitation Aids Technology and System of the Ministry of Civil Affairs National Research Center for Rehabilitation Technical Aids Beijing 100176 China Beijing Advanced Innovation Center for Biomedical Engineering Beihang University Beijing 100191 China Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education School of Biological Science and Medical Engineering Beihang University Beijing 100191 China

In this study, mechanical properties of bionic porous structures with diagonal-symmetrical and midline-symmetrical unit cells were studied when the porosities were same. Three typical unit cells (Diamond (DO), Rhombic Dodecahedron (RD), and Octet Truss (OT)) were selected, in which DO has diagonal-symmetrical shape, while RD and OT share midline-symmetrical structure. Based on the same porosity, corresponding models were designed, and Ti6Al4V samples were manufactured by electron beam melting. Then, using Mechanical Properties Testing (MPT) and Finite Element Analysis (FEA) methodologies, mechanical properties and transmissions of different porous structures were evaluated. Besides, composition and details before and after printing were analyzed with Energy Dispersive Spectrometer (EDS), X-ray diffraction (XRD) and Scanning Electron Microscope (SEM). MPT results showed that midline-symmetrical shape would have superior compressive performance than diagonal-symmetrical shape, but opposite trend for the torsion performance, which were in line with FEA prediction. Furthermore, effective modulus of DO, RD and OT were 2.59 GPa, 4.89 GPa, and 1.77 GPa, approximating the mechanical properties of human bones. Additionally, manufacturing defects and discrepancies between FEA and MPT were found. This study would provide great helps for unit cell selection and initial mechanical properties matching for optimum bone implants.

关键词： bionic design porous implant mechanical properties unit cell additive manufacturing 3D printing

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Thickness-driven quantum anomalous hall phase transition in magnetic topological insulator thin films

arXiv

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arXiv 2021年

作者： Ji, Yuchen Liu, Zheng Zhang, Peng Li, Lun Qi, Shifei Chen, Peng Zhang, Yong Yao, Qi Liu, Zhongkai Wang, Kang L. Qiao, Zhenhua Kou, Xufeng ShanghaiTech Laboratory for Topological Physics School of Physical Science and Technology ShanghaiTech University Shanghai200031 China University of Chinese Academy of Sciences Beijing101408 China International Center for Quantum Design of Functional Materials Hefei National Laboratory for Physical Sciences at Microscale CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics Department of Physics University of Science and Technology of China Hefei Anhui230026 China Department of Electrical Engineering University of California Los AngelesCA90095 United States School of Information Science and Technology ShanghaiTech University Shanghai20031 China College of Physics Hebei Normal University Shijiazhuang Hebei050024 China

The quantized version of anomalous Hall effect realized in magnetic topological insulators (MTIs) has great potential for the development of topological quantum physics and low-power electronic/spintronic applications. To enable dissipationless chiral edge conduction at zero magnetic field, effective exchange field arisen from the aligned magnetic dopants needs to be large enough to yield specific spin sub-band configurations. Here we report the thickness-tailored quantum anomalous Hall (QAH) effect in Cr-doped (Bi,Sb)2Te3thin films by tuning the system across the two-dimensional (2D) limit. In addition to the Chern number-related metal-to-insulator QAH phase transition, we also demonstrate that the induced hybridization gap plays an indispensable role in determining the ground magnetic state of the MTIs, namely the spontaneous magnetization owning to considerable Van Vleck spin susceptibility guarantees the zero-field QAH state with unitary scaling law in thick samples, while the quantization of the Hall conductance can only be achieved with the assistance of external magnetic fields in ultra-thin films. The modulation of topology and magnetism through structural engineering may provide a useful guidance for the pursuit of QAH-based new phase diagrams and functionalities. © 2021, CC BY.

关键词： Topology

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Lightweight Task-Oriented Semantic Communication Empowered by Large-Scale AI Models

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IEEE Transactions on Vehicular technology 2025年

作者： Liu, Chuanhong Guo, Caili Yang, Yang Chen, Mingzhe Quek, Tony Q. S. Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing100876 China Beijing University of Posts and Telecommunications Beijing Laboratory of Advanced Information Networks School of Information and Communication Engineering Beijing100876 China University of Miami Department of Electrical and Computer Engineering Institute for Data Science and Computing Coral GablesFL United States Singapore University of Technology and Design Dept. of Information Systems Technology and Design 487372 Singapore

Recent studies have focused on leveraging large-scale artificial intelligence (LAI) models to improve semantic representation and compression capabilities. However, the substantial computational demands of LAI models pose significant challenges for real-time communication scenarios. To address this, this paper proposes utilizing knowledge distillation (KD) techniques to extract and condense knowledge from LAI models, effectively reducing model complexity and computation latency. Nevertheless, the inherent complexity of LAI models leads to prolonged inference times during distillation, while their lack of channel awareness compromises the distillation performance. These limitations make standard KD methods unsuitable for task-oriented semantic communication scenarios. To address these issues, we propose a fast distillation method featuring a pre-stored compression mechanism that eliminates the need for repetitive inference, significantly improving efficiency. Furthermore, a channel adaptive module is incorporated to dynamically adjust the transmitted semantic information based on varying channel conditions, enhancing communication reliability and adaptability. In addition, an information bottleneck-based loss function is derived to guide the fast distillation process. Simulation results verify that the proposed scheme outperform baselines in term of task accuracy, model size, computation latency, and training data requirements. © 1967-2012 IEEE.

关键词： NP-hard

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Neutron physical feasibility of small modular design of dual fluid reactor 27

Neutron physical feasibility of small modular design of dual...

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27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Wang, Xiang Zhang, Qian He, Xun Du, Zhuoqi Seidl, Marcus Macian-Juan, Rafael Czerski, Konrad Dabrowski, Mariusz College of Nuclear Science and Technology Harbin Engineering University Harbin Heilongjiang China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China Institute of Nuclear Engineering Technical University of Munich Garching Bayern Germany Faculty of Mathematics and Physics University of Szczecin Szczecin Poland

ISBN: (纸本)9784888983051

The Dual Fluid reactor (DFR) is a fast reactor concept proposed by the Institute of Solid-state- and Nuclear physics (IFK) in Berlin. The design of DFR aims to combine the Gen-IV Molten Salt reactor (MSR) and the Liquid-Metal Cooled reactor (SFR, LFR), which means that the molten-salt fuel is no more used as coolant while the heat is removed in a separate loop by liquid lead, to improve these two concepts. Without control rods, DFR is given hope to react and take steps to the change of operation conditions automatically by its inertial negative temperature feedback. Since fuel and coolant are both liquid, the circulation speed of each liquid is considered capable to adjust operational parameters for DFR. The original design of a 3000MWth (Wang, 2017) and a downscaled version of 500MWth (He, 2016) were analyzed in the aspects of reactor physics and thermal-hydraulics. For the practical purpose, this paper has proposed a small modular version of the DFR, which has power output of 2MWth. The reactor with such power level is expected in various applications. Therefore, it is necessary to perform the more explicit analysis on the design than the previous ones. The analysis focuses on the neutronic calculations with the default fuel salt of U-Pu mixture under steady state conditions. Copyright © 2018-2019 by JSME

关键词： Coolants

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Traffic Control Task Scheduling Optimization Approach of Urban Road Intersection Based on Edge Computing

Traffic Control Task Scheduling Optimization Approach of Urb...

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Artificial Intelligence, Networking and Information technology (AINIT), International Seminar on

作者： Xiang Fu Fei Wang Nan Ji Yilong Ren School of Transportation Science and Engineering Beihang University BUAA Beijing China Key Laboratory of Space Utilization Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing China Intelligent Transport System (ITS) R & D Center Shanghai Urban Construction Design and Research Institute (Group) Co. Ltd. Shanghai China

ISBN: (纸本)9781665412971

With the development of Connected Automated Vehicles (CAV), there will be a long period of mixed driving, which causes the traffic control task at intersections becomes much more complicated. The control tasks would include not only the traffic signal timing optimization but also the computing tasks for different levels of vehicles. Current control task management methods are proved to be inferior to solve this problem. In this paper, we propose an intersection control task scheduling optimization approach based on edge computing. Firstly, the traffic control edge computing system for intersections is constructed. Then, different types of control tasks are listed. Criticality and timeliness are introduced to calculate the control task's dynamic priority. The control task scheduling optimization model, which considering these two parameters is proposed. At last, the improved Hungarian algorithm is applied to solve the proposed task scheduling optimization model. Simulation results show that our proposed methods can effectively reduce task processing costs and ensure the critical tasks execute firstly.

关键词： Processor scheduling Computational modeling Heuristic algorithms Traffic control Scheduling Timing Task analysis

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design of Cooled Dual-Group Linked Continuous Zoom Hybrid Refractive-Diffractive system Based on Double-Layer Diffractive Element

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Guangxue Xuebao/Acta Optica Sinica 2025年第9期45卷

作者： Ma, Chengshuang Li, Ying Xue, Changxi Key Laboratory of Advanced Optical System Design and Manufacturing Technology of Jilin Province Changchun University of Science and Technology Jilin Changchun130022 China Department of Instrument Science and Technology Changchun University of Science and Technology Jilin Changchun130022 China School of Optoelectronic Engineering Changchun University of Science and Technology Jilin Changchun130022 China

Objective In recent years, with increasing demands for imaging optical systems and continuous advancements in manufacturing technologies, dual-band infrared zoom optical systems have been widely applied in various fields such as military reconnaissance, precision guidance, airborne electro-optical pods, aerospace, security, and night vision surveillance. Continuous zoom infrared lenses enable target searching over a wide field of view and rapid switching to a narrow field of view for precise tracking and observation. This capability is particularly advantageous for tracking high-speed moving targets, addressing the issue of losing targets during field-of-view switching in stepped zoom lenses. However, dual-band infrared zoom systems face challenges such as complex structures, difficult aberration correction, suboptimal image quality, and limited material selection. Therefore, developing a high-performance dual-band infrared zoom optical system is crucial for advancing imaging optical systems. Methods First, in the dual-band infrared range of 3.7‒4.8 μm and 8‒10 μm, a double-layer diffractive optical element (DOE) is designed using a method that maximizes polychromatic integrated diffraction efficiency (PIDE) considering angular-wavelength characteristics. The wavelengths corresponding to the maximum PIDE values are selected as the design wavelengths, and the corresponding microstructure height parameters are calculated. The designed double-layer DOE achieves a comprehensive PIDE of 98.29%, demonstrating high diffraction efficiency across the dual-band infrared range. Second, a dual-group linked zoom model is derived. Using this model, the component distances at different focal lengths are calculated. These parameters are then input into optical design software to develop a dual-band infrared zoom optical system with a continuous zoom range of 30‒300 mm. However, the initial system exhibits suboptimal image quality. Finally, the high-efficiency double-layer DOE is in

关键词： Thermography (imaging)

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Improvements of the CMFD acceleration capability of OpenMOC

Improvements of the CMFD acceleration capability of OpenMOC

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2019 International Conference on Mathematics and Computational Methods Applied to Nuclear science and Engineering, M and C 2019

作者： Wu, Wenbin Giudicelli, Guillaume Smith, Kord Forget, Benoit Yao, Dong Luo, Qi Department of Nuclear Science and Engineering Massachusetts Institute of Technology 77 Massachusetts Ave CambridgeMA02139 United States Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China NO. 328 Section 1 Changshun Ave Shuangliu District Chengdu Sichuan Province610213 China

ISBN: (纸本)9780894487699

Due to its computational efficiency and geometrical flexibility, the Method of Characteristics (MOC) has been widely used for light water reactor lattice physics analysis. Usually acceleration methods are necessary for MOC to achieve acceptable convergence on practical reactor physics problems. Among them, Coarse Mesh Finite Difference (CMFD) is very popular and can drastically reduce the number of transport iterations. In OpenMOC, CMFD acceleration was implemented but had the limitation of supporting only a uniform CMFD mesh, which would often lead to splitting MOC source regions, thus creating an unnecessary increase in computation and memory use. In this study, CMFD acceleration with a nonuniform Cartesian mesh is implemented into OpenMOC. We also propose a quadratic fit based CMFD prolongation method in the axial direction to further improve the acceleration when multiple MOC source regions are contained in one CMFD coarse cell. Numerical results are presented to demonstrate the improvement of the CMFD acceleration capability in OpenMOC in terms of both efficiency and stability. © 2019 American Nuclear Society. All rights reserved.

关键词： Acceleration

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An efficient design and implementation of deduplication on open-channel SSDs 21

An efficient design and implementation of deduplication on o...

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21st IEEE International Conference on High Performance Computing and Communications, 17th IEEE International Conference on Smart City and 5th IEEE International Conference on Data science and systems, HPCC/SmartCity/DSS 2019

作者： Hu, Qiqi Chen, Jianxi Feng, Dan Yang, Qing Liu, Bo Wuhan National Laboratory for Optoelectronics Key Laboratory of Information Storage System Engineering Research Center of Data Storage Systems and Technology Ministry of Education of China Huazhong University of Science and Technology Wuhan China Hikstor Technology Co. LTD. Zhejiang China

ISBN: (纸本)9781728120584

Since the number of NAND flash write cycles reaches the upper limit, data cannot be reliably stored. Therefore, the lifespan of Solid State Disks (SSDs) is limited, making it impossible to become a reliable storage device in a write-intensive data center. Deduplication can effectively reduce write traffic and increase the lifespan of SSDs. However, the fingerprint calculation overhead in the traditional data deduplication scheme is too large, which will reduce the write performance of the SSDs. In this paper, we propose a new deduplication scheme D-pblk based on Open-Channel SSDs(OCSSDs), which can reduce fingerprint computing overhead with modern high performance CPUs. In D-pblk, we use the light-weight hash CRC32 to filter most of the non-duplicated data, and When CRC32 is first hit, we read the data from Open-Channel SSDs and calculate the heavy-weight hash SHA-1 for accurate comparison, which reducing fingerprint computing overhead and hardly affects the deduplication rate of workloads. And we use multi-thread to calculate fingerprints in parallel, further reducing fingerprint computing overhead. In addition, we use double ring buffers to solve the problem that the data size after deduplication may not match the size of a flash page. We use FEMU to simulate Open-Channel SSDs for evaluation. The experimental results show that D-pblk can achieve the deduplication rate ranging from 4.61% to 31.63% and the write latency is improved by a factor of up to 29%. © 2019 IEEE.

关键词： Program processors

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Experimental research of jet diameter on heat transfer in a small steel containment

Experimental research of jet diameter on heat transfer in a ...

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2019 Transactions of the American Nuclear Society, ANS 2019

作者： Wang, Shengfei Liu, Yusheng Jiang, Xiaowei Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy North China Electric Power University 2 Beinong Road Changping District Beijing102206 China Nuclear and Radiation Safety Center MEP Beijing100084 China Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu612013 China

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The application of Deep Reinforcement Learning in Coordinated Control of Nuclear reactors

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Journal of Physics: Conference Series 2021年第1期2113卷

作者： Jing Li Yanyang Liu Xianguo Qing Kai Xiao Ying Zhang Pengcheng Yang Yue (Marco) Yang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 610213 China Department of Engineering The University of Sydney Sydney 2006 Australia

The nuclear reactor control system plays a crucial role in the operation of nuclear power plants. The coordinated control of power control and steam generator level control has become one of the most important control problems in these systems. In this paper, we propose a mathematical model of the coordinated control system, and then transform it into a reinforcement learning model and develop a deep reinforcement learning control algorithm so-called DDPG algorithm to solve the problem. Through simulation experiments, our proposed algorithm has shown an extremely remarkable control performance.

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