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SSRN 2024年

作者： Liu, Lin Zhang, Sen Liu, Lang Xie, Chiyu Wang, Lixiu Liu, Yijia Zhu, Jing Feng, Libo School of Mathematics and Physics University of Science and Technology Beijing Beijing100083 China State key laboratory of advanced metallurgy University of Science and Technology Beijing Beijing100083 China School of Civil and Resource Engineering University of Science and Technology Beijing Beijing100083 China School of Mathematical Sciences Queensland University of Technology GPO Box 2434 BrisbaneQld4001 Australia

This paper considers the oscillatory flow of the Oldroyd-B fluid in a tube with a right triangular cross-section. The partial differential equation for describing the unidirectional flow of Oldroyd-B fluid is derived. For treating the triangular region, the unstructured mesh finite element method is applied. For verifying the accuracy of the finite element method, the source term is introduced and the exact solution is constructed. We obtain an analytical solution for the steady-state form in the isosceles triangular cross-section tube and analyze the effects of different parameters on the velocity amplitude and phase difference of the Oldroyd-B fluid flow. In addition, the dynamic characteristics for the unsteady-state Oldroyd-B fluid flow are discussed and the influence of the involved parameters, such as the pressure gradient, the relaxation and retardation time parameters on the velocity distribution are also investigated and the flow mechanism is analyzed graphically. At the same condition, we find that only the tube with an isosceles right triangle cross-section can produce the oscillatory flow. © 2024, The Authors. All rights reserved.

关键词： Finite element method

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Collision Attack Framework on RIPEMD-128

Collision Attack Framework on RIPEMD-128

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International Conference on Artificial Intelligence and advanced Manufacturing (AIAM)

作者： Jingyu Li Guang Zeng Yang Yang State Key Laboratory of Mathematical Engineering and Advanced Computing PLA Strategic Force Information Engineering University Zhengzhou China State Key Laboratory of Mathematical Engineering and Advanced Computing PLA Information Engineering University Zhengzhou China Trusted Computing and Information Assurance Laboratory Institute of Software Chinese Academy of Sciences Beijing China

In the last few years, the hash functions are the very common and essential primitives implemented in lots of fields. RIPEMD-128, a member of MD-family hash function, has been found collisions on the full round. In this paper, we further analyze the property about the security against collision attack of RIPEMD-128. The collision attack framework for RIPEMD-128 is proposed in order to provide ideas for other hash functions. The framework consists of three parts namely choosing a message word difference insertion, constructing differential characteristics and collision search phase. Cryptographic techniques including message modification is also introduced to reduce the complexity.

关键词： Hash functions Complexity theory Cryptography Artificial intelligence

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The design of rotor position observer for dfig during transient grid voltage imbalance

UPB Scientific Bulletin, Series C: Electrical Engineering an...

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UPB Scientific Bulletin, Series C: Electrical engineering and Computer Science 2020年第4期82卷 275-286页

作者： Wu, Qianqiong Chang, Xiaoying Zhao, Meihua Li, Mingwei College of electrical engineering and automation Luoyang Institute of Science and Technology Luoyang China State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou China

A rotor position observer based on hysteresis comparator (HC) was presented to acquire the rotor position angle of the Doubly-fed induction generator (DFIG) under unbalanced grid Voltage conditions. The position and velocity of DFIG’s rotor were estimated by the observer with hysteresis comparator. The system structure is relatively simple, without adjusting any parameters, easy to achieve. Simulation model for wind energy generation system-with DFIG is set up. The simulation results show that the control strategy is feasible and efficient. © 2020, Politechnica University of Bucharest. All rights reserved.

关键词： Asynchronous generators

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Uncovering hidden Fermi surface instabilities through visualizing unconventional quasiparticle interference in CeTe3

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Physical Review Materials 2024年第10期8卷 104004页

作者： B. R. M. Smith Y. Fujisawa P. Wu T. Nakamura N. Tomoda S. Kuniyoshi D. Ueta R. Kobayashi R. Okuma K. Arai K. Kuroda C.-H. Hsu G. Chang C.-Y. Huang H. Lin Z. Y. Wang T. Kondo Y. Okada Quantum Materials Science Unit Research Institute for Synchrotron Radiation Science Department of Physics and Chinese Academy of Sciences Key Laboratory of Strongly-Coupled Quantum Matter Physics Faculty of Science Institute of Materials Structure Science Institute for Solid State Physics (ISSP) Graduate School of Advanced Science and Engineering International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SCKM Division of Physics and Applied Physics School of Physical and Mathematical Sciences Institute of Physics Trans-scale Quantum Science Institute

The charge density wave (CDW) state is a widespread phenomenon in low-dimensional metals/semimetals. The spectral weight of the associated folded bands (shadow bands) can be an intriguing trigger leading to additional Fermi surface instability and unexplored phase transitions. The rare earth tri-telluride CeTe3 exhibits a single CDW stabilized below ∼400K and antiferromagnetism below ∼3K. The distinct periodicities between the Te-square net, the CeTe block layer, and the CDW give rise to rich shadow band formations. In this work, we reveal the predominant scattering between the original and shadow bands at 4 K, with the scattering within the original bands being relatively suppressed at Fermi energy. This unconventional quasiparticle scattering collectively underscores the vital role of the shadow bands' spectral weight and the exotic hidden matrix element effect, which are crucial for controlling electronic properties in this system. Furthermore, our finding points to the existence of rich and unexplored Fermi surface instabilities, which potentially play a role in controlling the nature of long-range antiferromagnetism at lower temperatures in the presence of finite charge-spin interaction.

关键词： Charge density waves Two-dimensional electron system Scanning tunneling microscopy

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NiCoP nanoleaves array for electrocatalytic alkaline H2 evolution and overall water splitting

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Journal of Energy Chemistry 2020年第11期29卷 395-401页

作者： Lei Chen Yaohao Song Yi Liu Liang Xu Jiaqian Qin Yongpeng Lei Yougen Tang State Key Laboratory of Powder Metallurgy Hunan Provincial Key Laboratory of Chemical Power SourcesCollege of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083HunanChina Energy Materials Computing Center Jiangxi University of Science and TechnologyNanchang 330013JiangxiChina Research Unit of Advanced Materials for Energy Storage Metallurgy and Materials Science Research InstituteChulalongkorn UniversityBangkok 10330Thailand

The development of non-precious, high-efficient and durable electrocatalysts for H2 evolution in alkaline media is highly desirable. Herein we report NiCoP nanoleaves array vertically grown on Ni foam for H2 evolution and overall water splitting via simple hydrothermal treatment and phosphorization. The selfsupported NiCoP nanoleaves architecture contributes to more exposed active sites, the smaller contact resistance between catalyst and substrate, faster ion diffusion and electron transfer. As a result, the optimized electrode requires only overpotentials of 98 and 173 mV to achieve current densities of 10 and100 m A cm-2 in 1.0 M KOH,respectively. Besides, used as both anode and cathode simultaneously, the electrode delivers current densities of 100 and 200 m A cm-2 at cell voltages of only 1.8 and 1.87 V, respectively. Moreover, the relatively high efficiency of about 11.4% for solar-driven water splitting further illustrates the application of our catalyst to sustainable development based on green technologies.

关键词： Electrocatalysis Hydrogen evolution reaction Alkaline media Water splitting Solar-driven electrolysis

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Convergence of physics-informed neural networks applied to linear second-order elliptic interface problems

arXiv

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arXiv 2022年

作者： Wu, Sidi Zhu, Aiqing Tang, Yifa Lu, Benzhuo State Key Laboratory of Scientific and Engineering Computing National Center for Mathematics and Interdisciplinary Sciences Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China School of Mathematical Sciences University of Chinese Academy of Sciences Beijing100049 China

With the remarkable empirical success of neural networks across diverse scientific disciplines, rigorous error and convergence analysis are also being developed and enriched. However, there has been little theoretical work focusing on neural networks in solving interface problems. In this paper, we perform a convergence analysis of physics-informed neural networks (PINNs) for solving second-order elliptic interface problems. Specifically, we consider PINNs with domain decomposition technologies and introduce gradient-enhanced strategies on the interfaces to deal with boundary and interface jump conditions. It is shown that the neural network sequence obtained by minimizing a Lipschitz regularized loss function converges to the unique solution to the interface problem in H2 as the number of samples increases. Numerical experiments are provided to demonstrate our theoretical analysis. Copyright © 2022, The Authors. All rights reserved.

关键词： Domain decomposition methods

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Correction to:High‑Index‑Faceted Ni3S2 Branch Arrays as Bifunctional Electrocatalysts for Efficient Water Splitting

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Nano-Micro Letters 2021年第1期13卷 317-318页

作者： Shengjue Deng Kaili Zhang Dong Xie Yan Zhang Yongqi Zhang Yadong Wang Jianbo Wu Xiuli Wang Hong Jin Fan Xinhui Xia Jiangping Tu State Key Laboratory of Silicon Materials Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Provinceand Department of Materials Science and EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China Guangdong Engineering and Technology Research Center for Advanced Nanomaterials School of Environment and Civil EngineeringDongguan University of TechnologyDongguan 523808People’s Republic of China School of Physical and Mathematical Sciences Nanyang Technological UniversitySingapore 637371Singapore School of Engineering Nanyang PolytechnicSingapore 569830Singapore Zhejiang Provincial Key Laboratory for Cutting Tools Taizhou UniversityTaizhou 318000People’s Republic of China

In the original publication,Figure S4 is an ancillary image to compare the specific surface areas of TiO2/Ni3S2 and Ni3S2 samples and it was incorrectly *** better serve our readers,the correct figure is provided in this *** BET values are correct and *** corresponding figure caption,data analysis and conclusions are not affected and thus not to be *** authors would like to apologize for any inconvenience caused.

关键词： Ni3S2 figure correct

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Construction of hollow mesoporous silica nanoreactors for enhanced photo-oxidations over Au-Pt catalysts

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National Science Review 2020年第11期7卷 1647-1655页

作者： Hao Tian Jinhui Zhao Xinyao Wang Lizhuo Wang Hao Liu Guoxiu Wang Jun Huang Jian Liu G.Q.(Max) Lu State Key Laboratory of Catalysis Dalian Institute of Chemical Physics (DICP)Chinese Academy of Sciences Centre for Clean Energy Technology School of Mathematical and Physical SciencesFaculty of ScienceUniversity of Technology Sydney Laboratory for Catalysis Engineering School of Chemical and Biomolecular Engineering Sydney Nano Institute The University of Sydney DICP-Surrey Joint Centre for Future Materials Department of Chemical and Process Engineering and Advanced Technology Institute University of Surrey University of Surrey

It is highly desirable to design hollow structures with multi-scale functions by mimicking cells for the construction of micro/nanoreactors. Herein, we report the construction of hollow-structured submicrometer-photoreactors with bimetallic catalysts loaded within mesoporous silicas. The synthesis parameters are optimized to study the evolution of hollow structure through hydrothermal treatment and an ‘adhesive-contraction’ formation mechanism is proposed. Au Pt@HMZS catalysts exhibited a broader absorbance region under visible light and the adsorption edge displayed a red-shift, indicating the strong metal–metal interactions at the alloy interface. The reaction performance of the coupled Au-Pt catalysts can be tuned to achieve excellent catalytic activity in cinnamyl alcohol oxidation to cinnamic acid for 3.1 mmol g-1with 99%selectivity. The proposed strategy to build hollow structures as multifunctional micro/nanoreactors is promising for the design of high-performance and sustainable catalysts for chemical synthesis.

关键词： nanoreactors photocatalytic oxidation metal nanoparticles mesoporous materials surface plasmonic resonance

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Accurate and Efficient Human Activity Recognition Through Semi-Supervised Deep Learning

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IEEE Sensors Journal 2025年第12期25卷 23105-23116页

作者： Long, Xianlei Wang, Ping Gu, Fuqiang Yan, Jinjin Yu, Fangwen Li, Yan Chen, Chao Guo, Songtao Chongqing University College of Computer Science Chongqing400044 China Harbin Engineering University Qingdao Innovation and Development Center Qingdao266400 China Tsinghua University Department of Precision Instrument Beijing China Macquarie University School of Computing Sydney Australia Chongqing University State Key Laboratory of Mechanical Transmission for Advanced Equipment Chongqing400044 China

In recent years, deep learning has been widely used for human activity recognition (HAR) based on wearable sensor data due to its excellent performance. However, deep learning approaches often need a large amount of labeled data to train the model. The collection of huge amounts of labeled activity data is usually labor-intensive and even cost-prohibitive, limiting the practical use of these methods. An effective way to address this issue is to use semi-supervised learning methods. Yet, most existing semi-supervised approaches fail to fully make use of unlabeled data to improve deep learning models' accuracy and generalizability. In this work, we propose an innovative Adaptive Confidence Semi-supervised HAR (ACS-HAR) method that can dynamically adjust the selective confidence threshold based on the model's learning state, thereby making more efficient use of unlabeled data. Experimental results on six public datasets demonstrate that our method outperforms traditional supervised methods by up to 5.20% accuracy and state-of-the-art semi-supervised methods by up to 3.30% *** release our code at https://***/objwww/ACS-HAR. © 2001-2012 IEEE.

关键词： Semi-supervised learning

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Origin Pilot: A quantum operating system for effecient usage of quantum resources

arXiv

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arXiv 2021年

作者： Kong, Weicheng Wang, Junchao Han, Yongjian Wu, Yuchun Zhang, Yu Dou, Menghan Fang, Yuan Guo, Guoping Origin Quantum Computing Company Limited Hefei230026 China CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou450002 China School of Computer Science and Technology University of Science and Technology of China Hefei230027 China

The operating system is designed to manage the hardware and software resources of a computer. With the development of quantum computing, the management of quantum resources and cooperation between quantum systems and other computing resources (e.g. CPU, GPU and FPGA etc.) become the key challenge for the application of quantum computing to solve real world problems. In this paper we propose a quantum operating system, Origin Pilot. Origin Pilot includes the module of quantum task scheduling, quantum resource management, quantum program compilation and qubits' automatic calibration. With these modules, Origin Pilot can manage the quantum computing resources and solve the multi-quantum processor scheduling problem. It can also allow the parallel execution of multiple quantum programs and calibrate the quantum resource effectively. Thus, the performance of resources is guaranteed and the resource utilization is improved. By comparing the results with and without Origin Pilot, we evaluate the impact on a quantum circuit's fidelity of qubits mapping algorithm. We also evaluate the effectiveness of automatic calibration and parallel execution of multi-quantum processors. Finally, Origin Pilot can be easily customized for hybrid computing resources. © 2021, CC BY-NC-SA.

关键词： Scheduling

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