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16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016

作者： He, Xiang Ma, Hongwei Wei, Wei National Key Laboratory of Science and Technology Aero-Engines Collaborative Innovation Center of Advanced Aero-Engine School of Energy and Power Engineering Beihang University Beijing100191 China China Aviation Powerplant Research Institute Zhuzhou412002 China

A whole-annulus unsteady numerical simulation is carried out to investigate the mechanism of the rotating stall in a 1.5-stage low-speed axial-compressor. By comparing the experimental and numerical results, the numerical results are validated. The numerical simulation captures the most features of the rotating stall of the 1.5-stage compressor observed from the experimental results. The unsteady bubble-like breakdown appears in the tip leakage vortex at the near stall condition. With the compressor throttling, the modal wave appears, increases in intensity and induces the part of the breakdown-vortex flow spilled over the adjacent blade leading-edge unsteadily, which form a spike. Consequently, the spikes emerge around the compressor annulus at the same time and the intensity and size of the spikes is increased rapidly during the inception period. At last, the spikes are merged into a large stall cell, which propagates around the annulus with 30% rotor speed. © Open Archives of the 16th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 2016. All rights reserved.

关键词： Vortex flow

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A novel method based on dynamic extinction angle of thyristor to mitigate commutation failure for HVDC

A novel method based on dynamic extinction angle of thyristo...

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The 16th IET International Conference on AC and DC Power Transmission (ACDC 2020)

作者： L. Kou Z. Mi X. Huang State Key Laboratory of Advanced Transmission Technology (Global Energy Interconnection Research Institute Ltd.) Changping District Beijing China Beijing Key Laboratory of DC Grid Technology and Simulation (Global Energy Interconnection Research Institute Ltd) Changping District Beijing China School of Electrical and Electronic Engineering North China Electric Power University Changping District Beijing China

Commutation failure is one of the critical problems for the HVDC transmission system. According to the theoretical analysis, the characteristics of the dynamic minimum extinction angle of the thyristor can be obtained. Considering the effect of the system operation conditions on the minimum extinction angle of the thyristor, a dynamic compensation method is proposed , which aims to mitigate the commutation failure of the HVDC transmission system. A simulation model based on CIGRE HVDC standard test system is built in PSCAD/EMTDC. The control performance of the proposed compensation method is verified by carrying out simulations under different fault scenarios. simulation results prove that the proposed compensation method, to some extent, has the ability to mitigate the consequential commutation failure under single-phase fault and three-phase fault. Therefore, the fault recovery characteristics and the reliability of HVDC transmission system can be effectively improved.

关键词： HVDC power transmission power transmission control HVDC power convertors power transmission faults commutation

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Conditional Generative Modeling for Amorphous Multi-Element Materials

arXiv

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arXiv 2025年

作者： Li, Honglin Liu, Chuhao Guo, Yongfeng Luo, Xiaoshan Chen, Yijie Liu, Guangsheng Li, Yu Wang, Ruoyu Wang, Zhenyu Wu, Jianzhuo Ma, Cheng Xie, Zhuohang Lv, Jian Ding, Yufei Zhang, Huabin Luo, Jian Zhong, Zhicheng Li, Mufan Wang, Yanchao Li, Wan-Lu Key Laboratory of Material Simulation Methods and Software Ministry of Education College of Physics Jilin University Changchun China Aiiso Yufeng Li Family Department of Chemical and Nano Engineering University of California La Jolla San DiegoCA United States Institute of Molecular Engineering Plus College of Chemistry Fuzhou University Fuzhou China College of Chemistry and Molecular Engineering Peking University Beijing China School of Physics Nankai University Tianjin China Institute of Modern Physics Fudan University Shanghai China Program in Materials Science and Engineering University of California La Jolla San DiegoCA United States School of Artificial Intelligence and Data Science University of Science and Technology of China Hefei230026 China Suzhou Institute for Advanced Research University of Science and Technology of China Suzhou215123 China International Center of Future Science Jilin University Changchun China Department of Computer Science and Engineering University of California La Jolla San DiegoCA United States Center for Renewable Energy and Storage Technologies Physical Science and Engineering Division King Abdullah University of Science and Technology Thuwal Saudi Arabia Suzhou Lab Suzhou215123 China

Amorphous multi-element materials offer unprecedented tunability in composition and properties, yet their rational design remains challenging due to the lack of predictive structure-property relationships and the vast configurational space. Traditional modeling struggles to capture the intricate short-range order that dictates their stability and functionality. We here introduce ApolloX, a pioneering predictive framework for amorphous multi-element materials, establishing a new paradigm by integrating physics-informed generative modeling with particle swarm optimization, using chemical short-range order as an explicit constraint. By systematically navigating the disordered energy landscape, ApolloX enables the targeted design of thermodynamically stable amorphous configurations. It accurately predicts atomic-scale arrangements, including composition-driven metal clustering and amorphization trends, which are well-validated by experiments, while also guiding synthesis by leveraging sluggish diffusion to control elemental distribution and disorder. The resulting structural evolution, governed by composition, directly impacts catalytic performance, leading to improved activity and stability with increasing amorphization. This predictive-experimental synergy transforms the discovery of amorphous materials, unlocking new frontiers in catalysis, energy storage, and functional disordered systems. Copyright © 2025, The Authors. All rights reserved.

关键词： Amorphization

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Numerical investigation of screech tones in 3-D modes by using an inviscid approach 48

Numerical investigation of screech tones in 3-D modes by usi...

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48th International Congress and Exhibition on Noise Control Engineering, INTER-NOISE 2019 MADRID

作者： Lee, Incheol Lee, Duck Joo Beijing Aeronautical Science and Technology Research Institute of COMAC Beijing Key Laboratory of Simulation Technology for Civil Aircraft Design China North of Future Science Park Changping District Beijing102211 China Korea Advanced Institute of Science and Technology 291 Daehak-Ro Yuseong-Gu Daejeon34141 Korea Republic of

ISBN: (纸本)9788487985317

Screech tones from supersonic inviscid jet were numerically investigated using computational aeroacoustics methods. A fourth order optimized compact scheme and fourth order Runge-Kutta scheme were used to solve three dimensional Euler equations. The tool was validated at the conditions of two supersonic flows: one is a perfectly expanded jet, and the other is three under-expanded jets. Extensive analysis was performed to investigate the characteristics of two three-dimensional modes, known as B and C modes, of screech tones including two mode transitions for various Mach numbers from 1.2 to 1.9. The directivity of a B-mode screech is investigated with the spectra of a Mach 1.3 jet. The directivity of B-mode screech tones is similar to the directivity of an acoustic dipole, whereas the directivity of C-mode screech tones is close to the directivity of an acoustic monopole. The wavelengths and amplitude of the reproduced screech tones showed good agreement with other results. The azimuthal directivity of both B and C modes becomes asymmetric after the second mode transition. It can be concluded that the present inviscid tool can numerically reproduce the screech tone including its non-linear mode transition without considering a viscous effect. © INTER-NOISE 2019 MADRID - 48th International Congress and Exhibition on Noise Control Engineering. All Rights Reserved.

关键词： Feedback

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Summary of Composite Material-Metal Connection technology

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IOP Conference Series: Earth and Environmental Science 2021年第5期632卷

作者： Jiapeng Dong Xu Cui Pu Zhao Daosheng Wang College of Civil Aviation Shenyang Aerospace University Shenyang Liaoning China State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Harbin Heilongjiang China

As high-performance and lightweight materials, such as aluminum alloy and titanium alloy, metals are still used in aerospace and aircraft industry. Therefore, the bonding process of composite materials and metals is one of the key issues to be urgently solved and developed in the aerospace industry. Therefore, the connection technology of CFRP to metal is reviewed in this paper. The implementation process of laser welding, friction welding and resistance welding and the types of connection materials are summarized.

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Experimental investigation on vibrations of a drilling riser in a jack-up platform under environmental and operating loads 29th

Experimental investigation on vibrations of a drilling riser...

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29th International Ocean and Polar Engineering Conference, ISOPE 2019

作者： Chen, Zhixiong Sun, Yuxin Zang, Zhipeng Wang, Cong State Key Laboratory of Hydraulic Engineering Safety and Simulation Tianjin University Tianjin China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai Jiao Tong University Shanghai China CNPC Engineering Technology Research Company Limited Tianjin China

ISBN: (纸本)9781880653852

In this study, a series of experiments were conducted in a wave/current flume to investigate the dynamic responses of a drilling riser for a jack-up platform under the environmental loads and operating loads, which include wave, current, top tension and combined conditions. The strain due to the vibration of the drilling riser in both in-line and cross-flow directions were measured with FBG strain sensors at four locations along the water depth. With the Fast Fourier Analysis to the strain data, the amplitude-frequency characteristics of the strain are obtained and the variation of the strain amplitude at the near-water surface of the cylinder with the wave factors, top tension and water depth is analyzed. Furthermore, the trajectory of the feature locations in the horizontal plane is obtained through modal analysis. It was found that the superimposition of the current on waves enhances the vibration of the riser compared with the pure wave condition;the trajectories of the characteristic locations are offset along IL direction under the combined action of wave and current. © 2019 by the International Society of Offshore and Polar Engineers (ISOPE).

关键词： Location

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Recent Widespread Deceleration of Global Surface Urban Heat Islands Unveiled by Satellites

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Geophysical Research Letters 2025年第12期52卷

作者： Wenfeng Zhan Long Li T. C. Chakraborty Leiqiu Hu Dazhong Wang Weilin Liao Shasha Wang Huilin Du Fan Huang Chunli Wang Zihan Liu Manchun Li Jiangsu Provincial Key Laboratory for Advanced Remote Sensing and Geographic Information Technology International Institute for Earth System Science Nanjing University Nanjing China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing China Frontiers Science Center for Critical Earth Material Cycling Nanjing University Nanjing China Pacific Northwest National Laboratory Richland WA USA Department of Atmospheric Science University of Alabama in Huntsville Huntsville AL USA Guangdong Key Laboratory for Urbanization and Geo-Simulation School of Geography and Planning Sun Yat-sen University Guangzhou China School of Geography and Ocean Science Nanjing University Nanjing China

Tracking the temporal dynamics of urban heat island (UHI) is critical for urban heat adaptation and mitigation strategies. However, whether UHI trends have shifted recently and their underlying drivers remain unknown. Here we investigate the variabilities in surface UHI trends and their associated determinants in 2,104 cities worldwide from 2000 to 2022. Our findings reveal that approximately half of the world's cities have experienced notable shifts in surface UHI trends, predominantly characterized by UHI deceleration. These shifts can be primarily attributed to alterations in vegetation trends during the day and to modifications in surface albedo and local warming trends at night. Our study challenges the conventional linear models commonly employed to estimate surface UHI trends, suggesting potential biases in such estimates. Our findings underscore the need for nuanced policies to curtail UHI growth by considering changes in urban underlying surfaces and background climate, particularly from a nonlinear perspective. Satellite records reveal that almost half of the world's cities experienced changes in urban heat island (UHI) trends, mainly slowdowns The UHI deceleration occurs at a more rapid speed in larger cities and old urban area as compared to smaller cities and newly urbanized area The changes in UHI trends are intricately regulated by nonlinear changes in urbanization processes and background climate changes Cities worldwide have witnessed a pervasive upward trend in surface urban heat island (UHI). However, it remains unclear whether this trend has changed. Here we reveal approximately half of the world's cities experiencing significant shifts in surface UHI trends, primarily characterized by deceleration. These shifts are mainly regulated by local changes in vegetation, albedo and air temperature. Our research underscores the limited understanding of temporal dynamics of surface UHI, offering the first indication of global prevalence of nonlinear trend

关键词： urban heat island land surface temperature interannual variation urban heat mitigation urban renewal

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Acoustic Emission Signal Feature Extraction of Inter-shaft Bearing Based on Quantum Entropy

Acoustic Emission Signal Feature Extraction of Inter-shaft B...

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Prognostics and System Health Management Conference (PHM-Qingdao)

作者： Yanting Ai Bowen Tian Jing Tian Fengling Zhang Zhi Wang Liaoning Key Laboratory of Advanced Measurement and Test Technology for Aviation Propulsion System Shenyang Aerospace University Shengyang China

For In order to solve the problems of weak signal characteristics and extraction difficulty during early fault stage of inter-shaft bearing, this paper introduces quantum theory into the calculation of information entropy, and proposes a new fault feature extraction method of inter-shaft bearings, quantum entropy. Firstly, based on the basic principle of quantum theory, the multi-qubit system of acoustic emission signal is established, and the calculation method of quantum entropy is constructed. Then, the four different working conditions of acoustic emission signal, i.e. outer ring fault, rolling element fault, inner ring fault and trouble-free, are simulated by the fault simulation test bench of inter-shaft bearing, and the acoustic emission signal is collected. After discussing the influence of different key parameters on quantum entropy, the quantum entropy of acoustic emission signals of inter-shaft bearings in four states is calculated, and the calculation results are analyzed. The experimental data analysis shows that the quantum entropy proposed in this paper can effectively extract the running state characteristics of the inter-shaft bearing and determine the fault types.

关键词： Entropy Feature extraction Acoustic emission Quantum mechanics Fault diagnosis Information entropy Rolling bearings

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Perturbative Quantum Monte Carlo Method for Nuclear Physics

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Physical Review Letters 2022年第24期128卷 242501-242501页

作者： Bing-Nan Lu Ning Li Serdar Elhatisari Yuan-Zhuo Ma Dean Lee Ulf-G. Meißner Graduate School of China Academy of Engineering Physics Beijing 100193 China School of Physics Sun Yat-Sen University Guangzhou 510275 China Faculty of Natural Sciences and Engineering Gaziantep Islam Science and Technology University Gaziantep 27010 Turkey Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University Guangzhou 510006 China Facility for Rare Isotope Beams and Department of Physics and Astronomy Michigan State University Michigan 48824 USA Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics Universität Bonn D-53115 Bonn Germany Institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron Physics Forschungszentrum Jülich D-52425 Jülich Germany Tbilisi State University 0186 Tbilisi Georgia

While first order perturbation theory is routinely used in quantum Monte Carlo (QMC) calculations, higher-order terms present significant numerical challenges. We present a new approach for computing perturbative corrections in projection QMC calculations. We demonstrate the method by computing nuclear ground state energies up to second order for a realistic chiral interaction. We calculate the binding energies of several light nuclei up to O16 by expanding the Hamiltonian around the Wigner SU(4) limit and find good agreement with data. In contrast to the natural ordering of the perturbative series, we find remarkably large second-order energy corrections. This occurs because the perturbing interactions break the symmetries of the unperturbed Hamiltonian. Our method is free from the sign problem and can be applied to QMC calculations for many-body systems in nuclear physics, condensed matter physics, ultracold atoms, and quantum chemistry.

关键词： Monte Carlo methods

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Review on design and evaluation of environmental photocatalysts

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Frontiers of Environmental Science & Engineering 2018年第5期12卷 9-40页

作者： Xin Li Jun Xie Chuanjia Jiang Jiaguo Yu Pengyi Zhang College of Forestry and Landscape Architecture Key Laboratory of Energy Plants Resource and UtilizationMinistry of AgricultureKey Laboratory of Biomass Energy of Guangdong Regular Higher Education InstitutionsSouth China Agricultural UniversityGuangzhou 510642China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China School of Environment State Key Joint Laboratory of Environment Simulation&Pollution ControlTsinghua UniversityBeijing 100084China

Heterogeneous photocatalysis has long been considered to be one of the most promising approaches to tackling the myriad environmental ***,there are still many challenges for designing efficient and cost-effective photocatalysts and photocatalytic degradation systems for application in practical environmental *** this review,we first systematically introduced the fundamental principles on the photocatalytic pollutant ***,the important considerations in the design of photocatalytic degradation systems are carefully addressed,including charge carrier dynamics,catalytic selectivity,photocatalyst stability,pollutant adsorption and photodegradation ***,the underlying mechanisms are thoroughly reviewed,including investigation of oxygen reduction properties and identification of reactive oxygen species and key *** review in environmental photocatalysis may inspire exciting new directions and methods for designing,fabricating and evaluating photocatalytic degradation systems for better environmental remediation and possibly other relevant fields,such as photocatalytic disinfection,water oxidation,and selective organic transformations.

关键词： Photocatalytic degradation Environmental remediation Charge carrier dynamics Reactive oxygen species O_(2)reduction

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