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Abnormal flow of α particles in heavy-ion collisions at intermediate energies

Physical Review C 2021年第4期103卷 044607-044607页

作者： G. Qu (曲国峰) Y. Huang (黄宇) D. Peng (彭丹) Z. Xu (徐子虚) W. Lin (林炜平) H. Zheng (郑华) G. Tian (田国玉) R. Han (韩瑞) C. Ma (马春旺) M. Huang (黄美容) P. Ren (任培培) J. Han (韩纪锋 ) Z. Yang (杨振雷) X. Liu (刘星泉) R. Wada Key Laboratory of Radiation Physics and Technology of the Ministry of Education Institute of Nuclear Science and Technology Sichuan University Chengdu 610064China School of Physics Henan Normal University Xinxiang 453007 China School of Physics and Information Technology Shaanxi Normal University Xi'an 710119 China Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China College of Physics and Electronics information Inner Mongolia University for Nationalities Tongliao 028000 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 610213 China Cyclotron Institute Texas A&M University College Station Texas 77843 USA

The experimentally observed abnormal α flow behavior from heavy-ion collisions at intermediate energies is investigated using the events of Ca40+Ca40 at 35 MeV/nucleon simulated with an improved antisymmetrized molecular dynamics model with specific consideration of the Fermi motion in the nucleon-nucleon collision process. Its possible origins in the processes from the fragment formation to the experimental flow extraction, i.e., dynamical process, sequential decay, experimental detection, and data analysis, are closely examined. It is found that the observed abnormal α flow behavior originates from the reconstruction of reaction planes in the flow extraction. How the abnormal α flow behavior is generated from the reaction plane reconstruction procedure is discussed.

关键词： Collective flow Low & intermediate energy heavy-ion reactions Models & methods for nuclear reactions

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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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Communication-Assisted Sensing in 6G Networks

arXiv

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arXiv 2023年

作者： Dong, Fuwang Liu, Fan Lu, Shihang Xiong, Yifeng Zhang, Qixun Feng, Zhiyong Gao, Feifei School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China School of Information and Electronic Engineering Beijing University of Posts and Telecommunications Beijing100876 China Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing100876 China Department of Automation Tsinghua University Beijing100876 China

Exploring the mutual benefit and reciprocity of sensing and communication (S&C) functions is fundamental to realizing deeper integration for integrated sensing and communication (ISAC) systems. This paper investigates a novel communication-assisted sensing (CAS) system within 6G perceptive networks, where the base station actively senses the targets through device-free wireless sensing and simultaneously transmits the estimated information to end-users. In such a CAS system, we first establish an optimal waveform design framework based on the rate-distortion (RD) and source-channel separation (SCT) theorems. After analyzing the relationships between the sensing distortion, coding rate, and communication channel capacity, we propose two distinct waveform design strategies in the scenario of target impulse response estimation. In the separated S&C waveforms scheme, we equivalently transform the original problem into a power allocation problem and develop a low-complexity one-dimensional search algorithm, shedding light on a notable power allocation tradeoff between the S&C waveform. In the dual-functional waveform scheme, we conceive a heuristic mutual information optimization algorithm for the general case, alongside a modified gradient projection algorithm tailored for the scenarios with independent sensing sub-channels. Additionally, we identify the presence of both subspace tradeoff and water-filling tradeoff in this scheme. Finally, we validate the effectiveness of the proposed algorithms through numerical simulations. Copyright © 2023, The Authors. All rights reserved.

关键词： Optimization

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Distributed Finite-Time Cooperative Localization for Three-Dimensional Sensor Networks

arXiv

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arXiv 2023年

作者： Wu, Jinze Zino, Lorenzo Lin, Zhiyun Rizzo, Alessandro The Department of Electronics and Telecommunications Politecnico di Torino Torino Italy Shenzhen Key Laboratory of Control Theory and Intelligent Systems School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China Peng Cheng Laboratory Shenzhen China The Institute for Invention Innovation and Entrepreneurship New York University Tandon School of Engineering BrooklynNY United States

This paper addresses the distributed localization problem for a network of sensors placed in a three-dimensional space, in which sensors are able to perform range measurements, i.e., measure the relative distance between them, and exchange information on a network structure. First, we derive a necessary and sufficient condition for node localizability using barycentric coordinates. Then, building on this theoretical result, we design a distributed localizability verification algorithm, in which we propose and employ a novel distributed finite-time algorithm for sum consensus. Finally, we develop a distributed localization algorithm based on conjugate gradient method, and we derive a theoretical guarantee on its performance, which ensures finite-time convergence to the exact position for all localizable nodes. The efficiency of our algorithm compared to the existing ones from the state-of-the-art literature is further demonstrated through numerical simulations. © 2023, CC BY.

关键词： Conjugate gradient method

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Virtual Reality technology in Peruvian Higher Education: Influence of University Tenure

Virtual Reality Technology in Peruvian Higher Education: Inf...

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Virtual Campus (JICV), X International Conference on

作者： Diego Vergara-Rodríguez Ronald Melgarejo Solis Álvaro Antón-Sancho Carlos Edmundo Navarro Depaz Pablo Fernández-Arias Agariadne Dwinggo Samala Technology Instruction and Design in Engineering and Education Research Group (TiDEE.rg) Catholic University of Ávila Ávila Spain Department of Virtual Education Web Digital School University Lima Penú Dept. System Engineering and Computer Science San Marcos University Lima Perú Facuity of Engineering Universitas Negeri Padang Padang West Sumatera Indonesia

ISBN: (数字)9798350343441

ISBN: (纸本)9798350343458

The use of virtual reality (VR) technologies in higher education has been growing in recent years due to their didactic potential in the most diverse areas of knowledge. However, the implementation of VR in universities is affected by several factors, including the level of digitization of the country or the tenure, private or public, of the universities. In this paper, a quantitative, descriptive and correlational research is carried out on the assessments of a group of professors in Peru about the use of VR in their lectures and on the differences in these perceptions according to the tenure of the university of the participants. For this purpose, a validated questionnaire was used, and its responses were statistically analyzed. The results reveal that professors express high ratings for the use of VR but show insufficient levels of digital skills for its use. In addition, professors from private universities give higher ratings of the didactic and usability aspects of VR. It is suggested that VR equipment and faculty training should be strengthened.

关键词： Training Virtual reality Usability

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BREAKING THE DEGREES-OF-FREEDOM LIMIT OF HOLOGRAPHIC MIMO COMMUNICATIONS: A 3-D ANTENNA ARRAY TOPOLOGY

arXiv

引用

arXiv 2023年

作者： Yuan, Shuai S.A. Wu, Jie Xu, Hongjing Wang, Tengjiao Li, Da Chen, Xiaoming Huang, Chongwen Sun, Sheng Zheng, Shilie Zhang, Xianmin Li, Er-Ping Sha, Wei E.I. College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China Anhui Province Key Laboratory of Simulation and Design for Electronic Information System Hefei Normal University Hefei230601 China Wireless Network Research Department Huawei Technologies Shanghai201206 China School of Information and Communications Engineering Xi’an Jiaotong University Xi’an710049 China School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu611731 China

The performance of holographic multiple-input multiple-output (MIMO) communications, employing two-dimensional (2-D) planar antenna arrays, is typically compromised by finite degrees-of-freedom (DOF) stemming from limited array size. The DOF constraint becomes significant when the element spacing approaches approximately half a wavelength, thereby restricting the overall performance of MIMO systems. To break this inherent limitation, we propose a novel three-dimensional (3-D) antenna array that strategically explores the untapped vertical dimension. We investigate the performance of MIMO systems utilizing 3-D arrays across different multi-path scenarios, encompassing Rayleigh channels with varying angular spreads and the 3rd generation partnership project (3GPP) channels. We subsequently showcase the advantages of these 3-D arrays over their 2-D counterparts with the same aperture sizes. As a proof of concept, a practical dipole-based 3-D array, facilitated by an electromagnetic band-gap (EBG) reflecting surface, is conceived, constructed, and evaluated. The experimental results align closely with full-wave simulations, and channel simulations substantiate that the DOF and capacity constraints of traditional holographic MIMO systems can be surpassed by adopting such a 3-D array configuration. © 2023, CC BY-NC-ND.

关键词： Energy gap

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A transfer learning based geometric position-driven machining error prediction method for different working conditions*

A transfer learning based geometric position-driven machinin...

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International Conference on Mechatronics and Machine Vision in Practice (M2VIP)

作者： Teng Zhang Hao Sun Lin Zhou Shengqiang Zhao Fangyu Peng Rong Yan National NC System Engineering Research Center School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan China Wuhan Digital Design and Manufacturing Innovation Center Co. Ltd China Wuhan China State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781665431545

Machining error is one of the most important indicators to evaluate the processing quality of thin-walled parts. With the development of Data science, the data-driven methods have become popular. But the condition that the model can work accurately on a new task is that the feature space and distribution of the data are the same. A sample-based transfer learning method driven by geometric position is utilized to quickly predict the machining errors of thin-walled parts under different working conditions. This method can fully learn the knowledge related to machining errors contained in the data through model training, and can apply this knowledge to accurately and quickly forecast machining errors under new working conditions. In the experimental scenario, this method has outstanding predictive performance. The average determination coefficient of the four groups of target domain experiments reached 0.96, and the average root mean square error is less than the machining error acquisition time to 22% of the original, reducing the dependence on time-consuming and expensive measurements greatly.

关键词： Employee welfare Training Mechatronics Transfer learning Machining Predictive models Data models

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Enhanced Low Voltage Ride Through (LVRT) Performance of Double-Fed Wind Generator (DFWG) with Grid-Forming (GFM) Capability

Enhanced Low Voltage Ride Through (LVRT) Performance of Doub...

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IEEE International Conference on Energy Internet (ICEI)

作者： Yunquan Fan Qianjin Hu Bojin Tang Xiaochen Huai Jinlian Liu Fan Tong Site Management Team Yunnan Mile Shidongshan Power Generation Co. Ltd. Mile China Site Management Team Yunnan Mile Shidongshan Three Gorges New Energy Power Generation (Mile) Co. Ltd. New Energy & New Power System Engineering Research Center China Three Gorges Corporation Science and Technology Research Institute Beijing China Electric Power Plan Design & Research Department Shanghai Investigation Design & Research Institute Co. Ltd. China

ISBN: (数字)9798331523558

ISBN: (纸本)9798331523565

Optimizing the Low Voltage Ride Through (LVRT) performance of Doubly-fed Wind Generation (DFWG) has always been an important task to improve the operational reliability of wind turbines. For this purpose, this paper put forwards a novel DFWG with enhanced LVRT performance, which adopts Grid-forming (GFM) strategy based on virtual synchronous control. First of all, the topology of DFWG and the performance requirements of LVRT are presented respectively. Then, the mathematical modeling and control strategy designs of the grid side converter and rotor-side converter of DFWG, also with the GFM strategy are carried out, respectively. On the basis, a complete GFM-DFWG control structure is formed finally. A typical simulation case and analysis is carried out to by setting several types of disturbance or faults at different occurrence time, corresponding to various voltage drop depths. Simulation results reveal that GFM-DFWG can adapt to greater LVRT depth ranging from 0.2p.u. to 1.0p.u. caused by different disturbance or faults. Even when the grid-connected voltage of DFWG drops by 0.8p.u., it is still able to recover to 0.9p.u. within about 150ms, although the oscillation amplitude and recovery time of the major U-I parameters may have an expansion as the LVRT depth increases, thus verifying the excellent fast response and voltage support effect of GFM.

关键词： Wind energy generation Low voltage Simulation Mathematical models Generators Distance measurement Wind turbines Voltage control Oscillators Grid forming

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Numerical analyses and experimental verification on multiphase flow measurements using a gamma-ray densitometer with blind-tee mixing 27

Numerical analyses and experimental verification on multipha...

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

作者： Ma, Yugao Cui, Yinghuan Hao, Yisheng Huang, Shanfang Pan, Yanzhi Yu, Hongxing Department of Engineering Physics Tsinghua University Beijing China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China Xi'an Jiaotong University Xi'an China

ISBN: (纸本)9784888983051

Gas-liquid two-phase flow widely exists in nuclear industry, where the heat flux is quite high. Accurate predictions of key parameters such as void fraction and gas volume fraction are important to the insurance of reactor safety operation. However, the accuracy of most multiphase flowmeters is flow-pattern dependent. A common way to homogenize the gas-liquid mixture and to eliminate the flow pattern effects is to install a blind-tee upstream of the flow measurement section to transform the horizontal flow to vertical upward flow. It is therefore of great interest to verify the effectiveness of flow mixing caused by blind-tee via experiments or simulation. In this study, the three-dimensional transient numerical simulation on gas-liquid two-phase flow was carried out by a commercial CFD software Fluent, using VOF model as multiphase model and Realizable k-Ε model as turbulence model. The results show that the flow develops from centrifugal flow to homogenous flow after passing around the bend and recovers its intermittent nature further downstream. CFD simulation analysis shows that there is a relatively ideal mixing effect after about 7 pipe diameters downstream. Therefore, the complexity of horizontal flow and intermittent flow are avoided by means of device design and measurement position optimization, which simplifies the measurement and calculation model. A flow-pattern based flow rate model is established by introducing the homogeneous-degree evaluation factor. The formula is simple and yet accurate. The relative average error of the model for predicting the total mass flow rate is within 2.66%. Copyright © 2018-2019 by JSME

关键词： Flowmeters

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Tool wear parameters identification in precision milling using a hybrid model combining cutting forces analytical model and Gaussian process regression method*

Tool wear parameters identification in precision milling usi...

引用

International Conference on Mechatronics and Machine Vision in Practice (M2VIP)

作者： Shengqiang Zhao Lin Zhou Hao Sun Fangyu Peng Rong Yan Teng Zhang National NC System Engineering Research Center School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan China Wuhan Digital Design and Manufacturing Innovation Center Co. Ltd China Wuhan China State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781665431545

In precision milling, tool wear has a significant impact on tool life prediction, machining accuracy and surface quality evaluation of workpiece. Tool wear pattern generally includes the increase of the tool flank wear width, as well as the expansion of the edge radius in precision process. Therefore, two tool wear parameters in precision milling have been generalized in this paper. The milling cutting force analytical model considering tool wear is set up to generate the data related to cutting force and tool wear parameters, which can be used as the dataset to construct and train the Gaussian process regression model. Finally, the trained regression model can output the prediction of tool flank wear width and edge radius as measured cutting forces treated as input values, which is helpful to realize the online monitoring of tool wear in the processing site environment. Consequently, the average relative prediction errors of tool flank wear width and edge radius are controlled within 2%, with the prediction time within 100ms.

关键词： Training Analytical models Parameter estimation Machine learning algorithms Force Milling Gaussian processes

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