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The Impact Failure and Energy Dissipation Mechanism of Polyethylene Laminates

Journal of Wuhan University of technology(Materials science) 2019年第3期34卷 723-727页

作者： SHU Zaiqin ZHANG Jinyong State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Institute of Material Science and EngineeringWuhan University of TechnologyWuhan430070China System Design Institute of Hubei Aerospace Technology Academy Wuhan430040China

The damage mechanism and energy dissipation of the Polyethylene (PE) laminates in impacting was investigated. It was found that the dissipated energy of the impacting sphere bullet by the 1-mmthick PE plate firstly increased with the impacting velocity increasing from 50 to about 300 m/s, and then decreased with the impacting velocity increasing up to 600 m/s. According to the measured deformation and damage degree, a numerical simulation of the dissipated energy was made and obvious offset was found with the experimental results. The quasi-static properties of the PE fibers, decreasing with increase in tensile velocity, may be the main reason for the offset.

关键词： polyethylene ballistic impact energy dissipation strain rate

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design and Experimental Validation of Sealing Assembly for Lunar Regolith Volatile Extraction Heating Furnace

Design and Experimental Validation of Sealing Assembly for L...

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IEEE International Conference on Robotics and Biomimetics

作者： Hongan Zhang Junyue Tang Yinchao Wang Zixiao Lu Bo Wang Miaoyan Cao Shengyuan Jiang Mechanical Engineering Yanshan University Qinhuangdao P. R. China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin P. R. China Mechatronics Institute Shenyang Aerospace University Shenyang P. R. China National Center for Nanoscience and Technlogy Chinese Academy of Science Beijing P. R. China China Academy of Space Technology Beijing P. R. China

A lunar regolith in-situ analysis payload deploying a mass spectrometer is proposed to exactly detect the water ice of the South Pole of the moon for China future lunar exploration missions. In order to realize the goal, an airtight heating furnace for volatile extraction from lunar regolith is desired. In this paper, sealing methods for lunar regolith volatile in heating furnace to future proposed in-situ sampling and analysis of lunar samples were investigated based on power requirements, furnace closing accuracy requirements, dust tolerance and operation in the Lunar environment. Methods implemented include a balanced metal hollow ring seal, a double channel ferrule tab ring radial seal and a spring energized seal. Comparing the performance of sealing methods under the above conditions, a spring energized seal is selected as the heating furnace seal. The materials and structure of the seal are designed based on the rigidity requirements, leakage rate requirements and working environment requirements. In order to test the sealing performance of seals after repeated sealing in high and low temperature environments, a seal leak detection system was designed. The test results indicate that the seal can meet the sealing performance requirements after repeated sealing at various temperatures.

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Channel Modeling and Multi-User Precoding for Tri-Polarized Holographic MIMO Communications

Channel Modeling and Multi-User Precoding for Tri-Polarized ...

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IEEE International Conference on Communications (ICC)

作者： Li Wei Chongwen Huang George C. Alexandropoulos Zhaohui Yang Jun Yang Wei E. I. Sha Mérouane Debbah Chau Yuen Singapore University of Technology and Design Singapore College of Information Science and Electronic Engineering Zhejiang University China Department of Informatics and Telecommunications National and Kapodistrian University of Athens Greece Technology Innovation Institute Abu Dhabi United Arab Emirates State Key Laboratory of Mobile Network and Mobile Multimedia Technology Shenzhen China Wireless Product R&D Institute ZTE Corporation Shenzhen China CentraleSupelec University Paris-Saclay Gif-sur-Yvette France School of Electrical and Electronics Engineering Nanyang Technological University Singapore

This paper studies the exploitation of triple polarization (TP) for multi-user (MU) holographic multiple-input multiple-output surface (HMIMOS) wireless communication systems, aiming at capacity boosting without enlarging the antenna array size. We specifically consider that both the transmitter and receiver are equipped with an HMIMOS comprising compact sub-wavelength TP patch antennas. To characterize TP MU-HMIMOS systems, a TP near-field channel model is proposed using the dyadic Green's function, whose characteristics are leveraged to design a user-cluster-based precoding scheme for mitigating the cross-polarization and inter-user interference contributions. A theoretical correlation analysis for HMIMOS with infinitely small patch antennas is also presented. According to the proposed scheme, the users are assigned to one of the three polarizations, which is easy to implement, at the cost, however, of reducing the system's diversity. Our numerical results showcase that the cross-polarization channel components have a non-negligible impact on the system performance, which is efficiently eliminated with the proposed MU precoding scheme.

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Dynamic failure of aramid paper honeycomb under intermediate strain rate loading

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Thin-Walled Structures 2025年 215卷

作者： Chen, Meiduo Zhang, Xianglin Xu, Songlin Ma, Hao Yuan, Liangzhu Xie, Yushan Zhang, Xiaoman Wang, Pengfei University of Science and Technology of China Department of Modern Mechanics CAS Key Laboratory for Mechanical Behavior and Design of Materials Anhui Hefei230027 China Beijing Institute of Space Long March Vehicle Beijing100076 China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

Investigation of the transformation process of failure mechanism for materials and structures under intermediate strain rate loading is of great significance. To achieve intermediate strain rate loading, a novel experimental technique is proposed using a high-speed-rotating eccentric cam to compress the specimen. The particle velocities and the stresses at both ends of the specimen are measured by the velocity interferometer system for any reflector (VISAR) and by the semiconductor strain gauges, respectively. The paper honeycomb specimens with four thicknesses (i.e. 2 mm, 3 mm, 5 mm, and 10 mm) are tested under strain rates ranging from 0.1 to 15 s-1. Local deformation evolution in the specimen is captured based on high-speed photography and analyzed by the digital image correlation method (DIC). The deformation under intermediate strain rate loading is distinguished by higher particle velocity and lower particle acceleration, which is different from those under the static compression (at lower strain rates) and the Split Hopkinson Pressure bar (SHPB) impacting (at higher lower strain rates). Based on the DIC results, the abnormal size effect of specimen 2 mm is due to the competition between in-plane shear failure and out-of-plane buckling. The theoretical model is then established by introducing two main parameters, i.e. the lateral weakening factor ξ and the dynamic parameter k, to describe respectively the effects of in-plane shearing and strain rate on the out-of-plane wall buckling, and the critical stress for specimen buckling is obtained. The results show that the buckling deformation and the half-wave number for buckling are sensitive to the two parameters. This work provides theoretical and experimental references for the study of thin-walled structures under intermediate strain rate. © 2025 Elsevier Ltd

关键词： Fracture mechanics

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Modification of severe accident analysis code for accident tolerant fuel (ATF) applications 27

Modification of severe accident analysis code for accident t...

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

作者： Xu, Tao Ma, Haifu Tian, Chao Wu, Yirui Yang, Junyun Wang, Kai Zhang, Bin Wang, Junlong Deng, Yaxin Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an Shaanxi China

ISBN: (纸本)9784888983051

After the Fukushima nuclear accident, we gradually realized the safety issues of the traditional UO2+Zr nuclear fuel system. Accident tolerance fuel (ATF) is a new generation fuel concept proposed to improve the performance of fuel elements against severe accidents, and can withstand the consequences of accidents for a long time while maintaining or improving their performance under normal operating conditions. Nowadays, the issue of the safe utilization of nuclear energy has attracted more and more attention. reactor severe accident simulation and analysis for ATF has also become one of the important research directions. MELCOR is a fully integrated engineering-grade computer code which can model severe accidents phenomena in light water reactors. However, the existing MELCOR code is only applicable for the UO2+Zr fuel system, and cannot simulate the behavior of the ATF. So it is necessary to modify the MELCOR code for ATF applications. Based on extensive investigation, multi-fuel and multi-cladding processing module and new physical properties of ATF are added to MELCOR. Also the heat transfer model, oxidation model and cladding failure model are modified, enabling the MELCOR code to calculate ATF behaviors. Afterwards, the model verification is carried out. Then the traditional UO2+Zr and five ATF combinations are applied to the traditional three-loop PWR nuclear power plant to perform the safety analysis under large break loss of coolant accident (LBLOCA). The calculation results show that ATFs have better accident tolerance ability than UO2+Zr fuel system used in the commercial PWR, and the temperature of the cladding rises more slowly. The cladding failure is also delayed to different extent. The ATF fuel system has a better performance under the severe accident condition. © 2018-2019 by JSME

关键词： Uranium dioxide

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Synthetic gene circuits moving into the clinic

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Quantitative Biology 2021年第1期9卷 100-103页

作者： Shuguang Peng Huiya Huang Ping Wei Zhen Xie MOE Key Laboratory of Bioinformatics and Bioinformatics Division Center for Synthetic and System BiologyDepartment of AutomationBeijing National Research Center for Information Science and TechnologyTsinghua UniversityBeijing 100084China Beijing Syngentech Co. LtdZhongguancun Life Science ParkChangping DistrictBeijing 102206China Center for Gene Circuit and Cell Design Shenzhen Institute of Synthetic BiologyShenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen 518055ChinaCenter for Quantitative BiologyAcademy for Advanced Interdisciplinary StudiesPeking UniversityBeijing 100871China

On November 28th 2020,SyngenTech,a China-based biotechnology company,announced that the company’s leading oncolytic virotherapeutic product,SynOVl.l,was approved for clinical trial by the *** and Drug *** synthetic bacterial or cell therapy[1,2],this is the first introduction of a viral therapy engineered using synthetic gene circuits into the *** with the clinical development of variable living therapeutics,we anticipate that synthetic gene circuits will receive increasing attention as a revolutionary technology to improve disease-treatment efficacy.

关键词： clinic clinical Together

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Deep reinforcement learning for combinatorial optimization: Covering salesman problems

arXiv

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arXiv 2021年

作者： Li, Kaiwen Zhang, Tao Wang, Rui Wang, Yuheng Han, Yi College of Systems Engineering National University of Defense Technology Changsha410073 China Hunan Key Laboratory of Multi-Energy System Intelligent Interconnection Technology HKL-MSI2T Changsha410073 China Graduate College National University of Defense Technology Changsha410073 China Science and Technology on Parallel and Distributed Processing Laboratory College of Computer National University of Defense Technology Changsha410073 China

This paper introduces a new deep learning approach to approximately solve the Covering Salesman Problem (CSP). In this approach, given the city locations of a CSP as input, a deep neural network model is designed to directly output the solution. It is trained using the deep reinforcement learning without supervision. Specifically, in the model, we apply the Multi-head Attention to capture the structural patterns, and design a dynamic embedding to handle the dynamic patterns of the problem. Once the model is trained, it can generalize to various types of CSP tasks (different sizes and topologies) with no need of re-training. Through controlled experiments, the proposed approach shows desirable time complexity: it runs more than 20 times faster than the traditional heuristic solvers with a tiny gap of optimality. Moreover, it significantly outperforms the current state-of-the-art deep learning approaches for combinatorial optimization in the aspect of both training and inference. In comparison with traditional solvers, this approach is highly desirable for most of the challenging tasks in practice that are usually large-scale and require quick decisions. Copyright © 2021, The Authors. All rights reserved.

关键词： Combinatorial optimization

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Effects of heaving condition on characteristics of system under forced circulation and natural circulation 27

Effects of heaving condition on characteristics of system un...

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

作者： Cai, Rong Mi, Zhengpeng Yue, Nina Fang, Hongyu Qiu, Suizheng Wang, Kai Qiu, Zhifang Science and Technology on Reactor System Design Technology Laboratory Chengdu China CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology Chengdu China Xi'an Jiaotong University Xi'an Shaanxi China Department of Nuclear Engineering and Management School of Engineering University of Tokyo Tokyo Japan

ISBN: (纸本)9784888983051

Under ocean conditions, the nuclear power plants have complex movements due to the effects of wind and wave. The thermal-hydraulic characteristics of the nuclear power plants under ocean conditions are influenced by its various motions. To ensure the safety of the reactor, the research on the effects of various motions on its thermal-hydraulic characteristics are necessary. The previous research has shown that heaving condition has more serious effects on the thermal-hydraulic characteristics of the nuclear power plants. In this paper, a thermal-hydraulic system code for ocean conditions named STAC was developed, and the STAC code was validated by test data. The effects of heaving conditions on the thermal-hydraulic characteristics of the system under forced circulation and natural circulation are studied with the STAC code. The simulation results show that the thermal parameters of the reactor system under heaving condition fluctuate periodically, and the fluctuation period is the same as the heaving period. The delay of the variation of circuit flow and the thermal inertia of the fuel material cause a phase difference between the fluctuations of the thermal parameters of reactor core. Heaving motion has less effect on the nuclear power system under forced circulation than that under natural circulation. As the amplitude of the acceleration increases, the fluctuation amplitudes of thermal-hydraulic parameters in the nuclear power system increase. Under heaving condition with short period, the fluctuation amplitudes of thermal-hydraulic parameters are affected by the heaving period. With the increase of the fluctuation period, the fluctuation amplitudes of thermal-hydraulic parameters increase gradually, and finally approach certain values. Copyright © 2018-2019 by JSME

关键词： Nuclear power plants

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Modeling of SiC cladding bowing behavior with consideration of spacer grids

Modeling of SiC cladding bowing behavior with consideration ...

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2019 Transactions of the American Nuclear Society, ANS 2019

作者： Li, Wei Shirvan, Koroush Massachusetts Institute of Technology CambridgeMA02139 United States Science Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

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An acceleration technique for method of characteristics based on preconditioning method and CUDA technique 27

An acceleration technique for method of characteristics base...

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

作者： Zheng, Yong Peng, Minjun Ping, A.N. Wei, L.U. Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Harbin Heilongjiang China

ISBN: (纸本)9784888983051

The method of characteristics (MOC) with matrix form has more favorable performance compared with its standard application. And the linear algebraic solver affects heavily the computation efficiency. As a Krylov subspace technique, the preconditioned generalized minimal residual algorithm (PGMRES) was proposed to solve the resulting linear system in previous work. To accelerate the iteration process further, the current study utilizes the GPU-based compute unified device architecture(CUDA) technique to program the massively parallel PGMRES. The sparse matrix vector multiplication(SpMV), the most time-consuming operation, was optimized using the coherent visiting and shared memory, which improves the parallel computing performance significantly. Based on the analysis of the numerical feature of the coefficient matrix, two parallel optimization strategies are proposed to deal with the first part of the matrix equation, and the different schemes are utilized to the different parts of the matrix based on the size of row vector, which are expected to improve the throughput of the SpMV operation. The benchmark problem HTTR(i.e. 2D high temperature engineering test reactor benchmark problem) has been simulated to verify the parallel code and evaluate the acceleration performance, and the numerical results demonstrate that the parallel strategies are efficient for the HTTR problem, and the speedup can achieve more than 5.5 times with the optimal strategy. © 2018-2019 by JSME

关键词： Linear systems

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