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7th IEEE International Conference on High Voltage Engineering and Application, ICHVE 2020

作者： Wang, Jilai Cheng, Huang Li, Jinzkun Wang, Xiaotian Yuan, Tao China Railway First Survery and Design Institue Group Co. Ltd. Xi'an China State Key Laboratory of Power Transmission Equipment System Security and New Technology Chongqing University Chongqing China

ISBN: (纸本)9781728155111

Because of the poor geographical environment of Qinghai-Tibet Railway, the catenary is vulnerable to strike by lightning. At the same time, as the Qinghai-Tibet Railway is laid on the bridge, the probability of lightning striking the rail increases with the bridge rising. As a result, the rail transient potential rises which seriously threatens the safety of equipment and personnel along the railway. Based on the engineering situation of Qinghai-Tibet Railway, this paper establishes a lightning catenary simulation model by the elec-tromagnetic transient simulation software ATP-EMTP. By combining the Elecrto-geometric Model(EGM), we analyzes the lightning withstand level of the catenary at different elevations and bridge heights. We also analyzes the influence of lightning current waveform and rail grounding resistance on rail transient potential when lightning strikes the rail. The simulation results show that the lightning withstand level of the catenary meets the requirements of regulations, and reducing the steepness of lightning current and rail ground resistance can effectively restrain the rise of rail transient potential. © 2020 IEEE.

关键词： Rails

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Two-stage optimization model of emergency power supply for improving resilience of the distribution network under flood disaster

Two-stage optimization model of emergency power supply for i...

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Science and technology Innovation (IAECST), International Academic Exchange Conference on

作者： Chao Liu Ping Zhou Yongzhong Zhou Qinan Liao Libo Tang Anqi Tao Qianggang Wang Chongqing Electric Power Design Institute Company of Limited Liability Chongqing China State Key Laboratory of Power Transmission Equipment and System Safety and New Technology Chongqing University Chongqing China

ISBN: (纸本)9781665402682

Flood disaster will cause large area power outage of the distribution network, causing huge economic loss. Emergency power supply is an effective strategy to improve the ability of distribution network to deal with flood disaster. However, due to the limitation of flood water, it is difficult for emergency power to reach the accident site, so mobile emergency power needs to be configured in advance. In this paper, a two-stage optimization model of emergency power supply for improving the resilience of distribution network is proposed. Considering the vulnerability modeling of different equipment under flood disaster, multiple island micro-networks are formed by combining medium and low mobile emergency generators and network reconstruction, and power supply can be quickly restored according to load priority order.

关键词： Technological innovation Emergency power supplies Distribution networks Generators Power system reliability Resource management Floods

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Hybrid Beamforming design for Millimeter Wave Multiuser MIMO systems with Dynamic Subarrays

arXiv

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arXiv 2022年

作者： Wang, Gengshan Yang, Zhijia Gong, Tierui State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang110016 China The Key Laboratory of Networked Control System Shenyang Institute of Automation Chinese Academy of Sciences Shenyang110016 China The Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences Shenyang110169 China The University of Chinese Academy of Sciences Beijing100049 China Singapore University of Technology and Design Singapore

In this letter, we investigate the millimeter wave (mmWave) downlink multiuser multiple-input multiple-output (MU-MIMO) system, adopting the dynamic subarray architecture at the base station and considering the multi-stream communication for each user. Aiming at maximizing the system spectral efficiency, we propose a novel hybrid beamforming design. First, assuming no inter-user interference (IUI), we easily get the optimal fully-digital beamformers and combiners using the singular value decomposition of each user channel and the waterfilling algorithm. Then, based on the obtained fully-digital beamformers, we propose a Kuhn-Munkres algorithm-assisted dynamic hybrid beamforming design, which guarantees that each radio-frequency chain is connected to at least one antenna. Finally, we propose to further project each obtained digital beamformer onto the null space of all the other equivalent user channels to cancel the IUI. Numerical results verify the superiority of our proposed hybrid beamforming design. © 2022, CC BY.

关键词： Millimeter waves

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Nonmonotonic enhancement of nanorod diffusion during 1D to quasi- 2D confinement transition

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Colloids and Surfaces A: Physicochemical and Engineering Aspects 2025年 724卷

作者： Jingbin Yang Jia Zhang Tianshun Shen Ruo-Yu Dong School of Astronautics Beihang University Beijing 100191 China Aircraft and Propulsion Laboratory Ningbo Institute of Technology Beihang University Ningbo 315100 China State Key Laboratory of High-Efficiency Reusable Aerospace Transportation Technology Beijing 100191 China Beijing Key Laboratory of System Design for Reusable Launch Vehicle Beijing 100191 China

Confined nanoparticle diffusion is ubiquitous and holds potential for applications in bio/nanotechnology. Contrary to the conventional belief that confinement slows down diffusion, recent studies have shown that increased confinement can increase the orientation of anisotropic nanoparticles, thereby enhancing their diffusional transport. Despite significant independent advances under 1D or 2D confinement, comparison of different confinement dimensionalities and their transition effects on particle diffusion are largely overlooked. Here, we constructed nanochannels transitioning from 1D (flat walls) to quasi- 2D confinement (sinusoidal walls) and investigated the diffusion of a single nanorod (SNR) using molecular simulations. Our results reveal that during dimensionality transition, stronger confinement improves SNR orientation along the unconstrained direction and leads to more rapid diffusion. The distinction is that, under 1D confinement, SNR diffusion is enhanced monotonically with increasing orientation along the unconstrained direction, whereas under quasi- 2D confinement, the relationship becomes non-monotonic, with an optimal situation yielding the fastest diffusion. We further confirmed that the confinement-induced enhancement of diffusion is not limited to specific confinement shapes, as demonstrated in geometries with sawtooth and square-wave walls, thereby validating its universality. This work could provide design principles for nanochannel geometries to regulate nanoparticle transport in applications such as drug delivery and nanofluidics.

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Study on the mechanism of microcrack propagation in bentonite under confining pressure conditions

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Quarterly Journal of Engineering Geology and Hydrogeology 2025年

作者： Guo, Jingna Liu, Jiangfeng Liu, Daoping Zhao, Yu Lei, Min Shi, Hao School of Applied Mathematics Chengdu University of Information Technology Sichuan Chengdu610225 China State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and Technology Jiangsu Xuzhou221116 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chendu610213 China School of Civil Engineering and Architecture Anhui University of Science and Technology Huainan232001 China

For underground nuclear disposal repositories, sealing performance is crucial to ensuring long-term operational safety. Bentonite, widely employed as a sealing material, effectively reduces leakage risks owing to its self-healing capacity. However, a comprehensive investigation of gas migration mechanisms in bentonite is imperative to elucidate the underlying leakage dynamics. This study not only offers theoretical insights for the safety assessment and design optimization of disposal repositories but also holds substantial practical significance in ensuring their secure performance. To accurately model gas migration in saturated bentonite, this study systematically investigates the effects of pore pressure on soil deformation and experimentally evaluates the impact of damage evolution on permeability and elastic modulus. Building on these experimental insights, we propose a coupled fluid-solid constitutive model. This model elucidates the progressive development of microcracks within bentonite under increasing gas pressure, providing a mechanistic understanding of fracture propagation in sealing systems. By integrating experimental data from bentonite hydration and gas breakthrough tests, the study verifies that gas migration under flexible boundary conditions is primarily governed by the dilatancy effect of bentonite. Furthermore, the model's validity and applicability are demonstrated. Subsequently, the model is employed to systematically investigate the influence of confining pressure on (1) the evolution of microcracks in bentonite, (2) permeability variations, and (3) gas breakthrough pressure thresholds. Based on these analyses, theoretical mitigation strategies to prevent gas breakthrough are established for specific confining pressure ranges. © 2025 The Author(s). Published by The Geological Society of London. All rights, including for text and data mining (TDM), artificial intelligence (AI) training, and similar technologies, are reserved. For permissions:

关键词： Microcracks

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Anomalous Polarization-Switching Phenomena and Noteworthy Pyroelectricity in Ferroelectric Hf0.5zr0.5o2 Polycrystalline Films

SSRN

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SSRN 2023年

作者： Wang, Xudong Zhou, Yong Xiong, Ke Wu, Shuyu Tu, Luqi Chen, Yan Wu, Shuaiqin Zeng, Jinhua Zheng, Yuqing Gu, Shiqun Luo, Man Lin, Tie Shen, Hong Meng, Xiangjian Liu, Qi Chu, Junhao Wang, Jianlu State Key Laboratory of Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai200083 China Key Laboratory of Microelectronics Device and Integrated Technology Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China Frontier Institute of Chip and System Fudan University Shanghai200433 China Shanghai Frontier Base of Intelligent Optoelectronics and Perception Institute of Optoelectronics Fudan University Shanghai200433 China Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Chinese Academy of Sciences Hangzhou330106 China BirenTech Shanghai201114 China Jiangsu Key Laboratory of ASIC Design School of Information Science and Technology Nantong University Jiangsu Nantong226019 China

Hafnia-based oxide thin films exhibit unconventional robust ferroelectricity at the nanoscale, paving the way for advancements in next-generation nanoelectronics. However, the stability and dynamics of ferroelectric polarization in hafnia-based oxides films, particularly at the nanoscale, warrant further exploration. In this study, we delve into the factors influencing the formation of the ferroelectric phase. Our findings illuminate that the confinement effect of the capped layer enhances the stabilization of the metastable orthorhombic phase, thereby bolstering its ferroelectricity and endurance. Furthermore, we identify an unprecedented polarization-switching behavior in HfO2-based ferroelectric films, characterized by a decrease in the remanent polarization and an increase in the coercive field as the temperature drops. This peculiar phenomenon can be ascribed to the reduction in the long-range interaction of polarization dipoles upon cooling, as evidenced by the dielectric spectrum. The diminished long-range interaction results in the emergence of nanodomains and a re-entrant relaxer behavior, offering novel insights into the origin of ferroelectricity and the stability of ferroelectric polarization in hafnia-based thin films. Given the commendable compatibility of Hf0.5Zr0.5O2 films with Si substrates and a pyroelectric coefficient of -62.1 μC/m2·K, they emerge as a prime candidate for sensor device applications. © 2023, The Authors. All rights reserved.

关键词： Thin films

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Effect of gamma radiation on the sensing characteristics of FPs and FBGs 27

Effect of gamma radiation on the sensing characteristics of ...

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27th International Conference on Optical Fiber Sensors, OFS 2020

作者： Li, Zhuoyue Xiao, Yaqin Ran, Zengling Yang, Tingting He, Xiu Xiao, Yanbo Shen, Feng Rao, Yunjiang He, Zhengxi Zhu, Jialiang He, Peng Xu, Sijie Chu, Wangwei Zeng, Debiao Fiber Optics Research Center Key Laboratory of Optical Fiber Sensing & Communications Ministry of Education University of Electronic Science & Technology of China Sichuan Chengdu611731 China Center for Optical Fiber Sensing Zhejiang Laboratory Hangzhou310000 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Chengdu Aircraft Industrial Group Co. Limited 610092 China

The sensing characteristics of Fabry-Perot interferometers (FPIs) and fiber Bragg gratings (FBGs) after irradiation were studied, in which pressure sensitivity of FPI was stable while temperature sensitivity curves of... 详细信息

ISBN: (纸本)9781557523075

关键词： Fiber Bragg gratings

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Assessment of Coupled Effect of Steam Pipes on Seismic Analysis of reactor Coolant system

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IOP Conference Series: Earth and Environmental Science 2021年第4期719卷

作者： Lijuan Li Zhenyu Liu Hui Li Xianhui Ye Honglei Ai National Key Laboratory of Science and Technology on Reactor System Design Technology Chengdu Sichuan China

reactor coolant system is connected with auxiliary pipes, surge pipes and steam pipes. In order to facilitate the dynamic analysis of reactor coolant system, it is necessary to decouple the pipes connected with the reactor coolant system. Although some international standards stipulating requirements for the decoupling of subsystems from the main system, in order to further explore the influence of decoupling steam pipes, the seismic response of reactor coolant system with or without steam pipes is simulated by using ANSYS program. Firstly, the modal analysis of reactor coolant system is carried out to analysis the influence of steam pipes on the resonant frequency of reactor system. Then, the standardized seismic dynamic analysis of reactor system with or without steam pipes is carried out. The nozzle load (inlet and outlet nozzle load of main device, such as reactor pressure vessel, steam generator, pump) and support load (of main device such as reactor pressure vessel, steam generator, pump) are output and compared. According to nozzle load and support load, it can be seen that the steam pipes have little influence on the seismic analysis of reactor coolant system, i.e. steam pipes can be decoupled in the seismic analysis of reactor coolant system.

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Anisotropy of thermal transport in phosphorene: A comparative first-principles study using different exchange-correlation functional

arXiv

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arXiv 2021年

作者： Zhang, Fa Zheng, Xiong Wang, Huimin Ding, Liang Qin, Guangzhao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China Hunan Key Laboratory for Micro-Nano Energy Materials & Device School of Physics and Optoelectronics Xiangtan University Hunan Xiangtan411105 China

Phosphorene, as a new type of two-dimensional (2D) semiconductor material, possesses unique physical and chemical properties, and thus has attracted widespread attention in recent years. With its increasing applications in nano/optoelectronics and thermoelectrics, a comprehensive study on its thermal transport properties is necessary. It has been concluded from previous studies that there exist vast difference and uncertainty in the theoretically predicted thermal conductivity, which is generally attributed to the selection of XC functional. However, there is no comprehensive investigation on this issue. In this paper, based on first-principles calculations using 12 different exchange-correlation (XC) functionals, the phonon transport properties of phosphorene are systematically studied by solving the Boltzmann transport equation (BTE). The results show noticeable differences in the phonon transport properties of phosphorene under different XC functionals. For instance, the thermal conductivity of phosphorene along the zigzag direction ranges from 0.51 to 30.48 Wm−1K-1, and that along the armchair direction ranges from 0.15 to 5.24 Wm−1K−1. Moreover, the anisotropy of thermal conductivity is between 3.4 and 6.9, which is fundamentally originated from the special hinge-like structure. This study conducts an in-depth analysis of phonon transport to reveal the effect and mechanism of different XC functionals for predicting thermal transport properties, which would provide a reference for future research on phosphorene and other novel materials. © 2021, CC BY.

关键词： Anisotropy

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Adaptive Robust Control of an Uncertain Robotic Manipulator with Guaranteed Transient and Steady state Performance

Adaptive Robust Control of an Uncertain Robotic Manipulator ...

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International Conference on Advanced Robotics and Mechatronics (ICARM)

作者： Yifan Liu Dejie Yu Zilu Wang Zheshuo Zhang Hui Yin State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha P. R. China Intelligent Transportation System Research Center School of information and electrical engineering Zhejiang Uni-versity City College Hangzhou Zhejiang P. R. China School of Mechanical and Automotive Engineering South China University of Technology Guangzhou Guangdong P. R. China

Guaranteeing human-specified performance in robot control subject to complex uncertainties is challenging. This study takes time-varying (possibly fast), bounded with unknown bounds uncertainties into consideration in controlling an uncertain robotic manipulator system (URMS). We employ an adaptive law to on-line estimate the unknown bounds for uncertainty compensation, and prescribed transient and steady state performance (TSSP) are guaranteed by using a state transformation technique. As a result, a class of adaptive robust control with prescribed TSSP is proposed. Simulation results are provided to validate the effectiveness of the proposed approach.

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