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Sobolev Mapping of the Bergman Projections on Generalized Hartogs Triangles

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Acta Mathematica Sinica,English Series 2024年第2期40卷 451-466页

作者： Hong Yan LIU zhen han TU School of Mathematics and Statistics Wuhan UniversityWuhan 430072P.R.China

In this paper,we investigate Sobolev mapping properties of the Bergman *** domain we focus on is defined byΩm/n:={(z,w)∈C^(1+N):|w1|<|z|m1/n1<1,…|wN|<|z|/m_(N)/n_(N)<1},where m=(m1,…mN)∈(Z^(+))^(N),n=(n1,…nN)∈(Z^(+))N,N∈Z^(+).Sobolev irregularity of the Bergman projections on 2 is *** also prove some Sobolev regularity results of the Bergman projections onΩm/n for m=(1,…1).

关键词： Bergman projections generalized Hartogs triangles Sobolev spaces

Photoinduced superlubricity on TiO_(2) surfaces

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Friction 2024年第3期12卷 428-438页

作者： ke han Liran MA Yu TIAN Jianbin LUO State key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Received:16 September 2022/Revised:28 October 2022/Accepted:27 December 2022The author(s)2022.

Superlubricity control is of great interest in both industry and scientific research,and several methods have been proposed to achieve this *** this work,ultraviolet(UV)light was introduced into titanium dioxide(TiO_(2))and silicon nitride(Si_(3)N_(4))tribosystems to accomplish photoinduced *** friction coefficients(COFs)between Si_(3)N_(4) balls and TiO_(2) plates in the mixtures of sulfuric acid(H^(2)SO_(4))solution and glycerol solution were obviously reduced,and the system entered the superlubricity region(COFhan that with UV *** formation of silica(SiO_(2))layers on the surfaces of Si_(3)N_(4) balls and the elastohydrodynamic effects were determined to be fundamental to the low friction in this experiment,and the enhancement of the combination between the TiO_(2) surface and the hydroxy group of glycerol by UV illumination was the key to the photoinduced superlubricity in this *** findings showed one method for achieving superlubricity by introducing a light field that could be further applied to special working conditions.

关键词： light control friction superlubricity glycerol titanium dioxide(TiO_(2))

Evaluation of Auto-Ignition Characteristics of Diesel Surrogate Fuels with the Same Derived Cetane Numbers at Changed Thermodynamic Environments

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Journal of Thermal Science 2024年第4期33卷 1590-1606页

作者： ZhanG Cong GUAN Yuanhang HUANG zhen han Dong key Laboratory for Power Machinery and Engineering Ministry of EducationShanghai Jiao Tong UniversityShanghai200240China College of Smart Energy Shanghai Jiao Tong UniversityShanghai200240China Shanghai Non-carbon Energy Conversion and Utilization Institute Shanghai200240China

The ignition tendency of diesel fuels is highly sensitive to ambient conditions and fuel *** this study,the ignition characteristics of different diesel surrogate fuels with the same derived cetane numbers(DCN)were measured and compared in varied thermodynamic and oxidizing *** combustion pressures,heat release rates,ignition delays,and combustion delays of the test fuels were *** experimental results showed that the diesel surrogate fuels with the same DCNs exhibit similar ignition propensity at standard DCN test ***,for the test conditions of high cetane fuels,high ambient temperatures,and suficient oxygen concentrations,surrogate fuels with the same DCN have similar ignition behaviors,and using the DCN to evaluate fuel ignition tendency is ***,for the test conditions of low cetane fuels,low ambient temperatures,and reduced oxygen concentrations,different ignition behaviors are observed for the surrogate fuels with the same DCN,so at these conditions using DCN as the evaluation index for fuel ignition tendency may lead to higher uncertainty.

关键词： diesel fuels surrogate fuels derived cetane numbers constant volume combustion chamber

One-step pore diffusion mechanism of Li^(+) in solid electrolyte interphase for fast-charging lithium-ion battery

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Rare Metals 2024年第7期43卷 3438-3440页

作者： Shan Wang Shu-Yuan Liu Alireza Khataee ke-zhen Qi College of Pharmacy Dali UniversityDali 671000China Research Laboratory of Advanced Water and Wastewater Treatment Processes Department of Applied ChemistryFaculty of ChemistryUniversity of TabrizTabriz 51666-16471Iran Peoples'Friendship University of Russia(RUDN University) Moscow117198Russian Federation

Li^(+) transport in solid electrolyte interphase is recognized as important factor,which has become a research ***,an one-step pore diffusion mechanism for Li^(+) transport through solid electrolyte interphase was proposed,which was different from previous two-step *** one-step pore diffusion process could effectively eliminate the dynamic limitations of Li^(+) transport in solid electrolyte interphase (SEI) for rapid charging *** work will contribute to the development of rapid charging lithium-ion batteries.

关键词： battery mechanism electrolyte

Molecular dynamics study of hydrogen-induced cracking behavior of ferrite–pearlite gas transmission pipeline steel

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Journal of Iron and Steel Research International 2024年第2期31卷 488-500页

作者： Tao-long Xu Si-han Guo Gong-zhen He Hao-yu han Petroleum Engineering School Southwest Petroleum UniversityChengdu610500SichuanChina Sichuan East Gas Transmission Sales Center of Sinopec Natural Gas Branch Wuhan430074HubeiChina

Hydrogen embrittlement of pipelines depends on the hydrogen-induced cracking behavior of the pipeline steel *** on molecular dynamics analysis,the ferrite–cementite(α-Fe/Fe3C)lamellar atomic structure with the Bagaryatskii orientation relationship was established,and stepwise relaxation of the conjugate gradient energy minimization and constant-temperature and constant-pressure relaxation were performed under NPT(the isothermal–isobaric)*** mechanical property curves of theα-Fe/Fe3C models were obtained under different cementite terminal plane structures,and the evolution of the atomic structure was analyzed in *** addition,the influence of different hydrogen concentrations,different temperatures,different strain rates,changes in voids,and different micro-degrees of freedom on the deformation and failure mechanism of the model was investigated,aiming to provide a reliable way to explore the micro-mechanism of macro-cracking behavior of pipeline steel.

关键词： Ferrite-cementite lamellar structure Pipeline steel Failure mechanism Crack propagation Molecular dynamics

Hyperbolic Tangent Function-Based Protocols for Global/Semi-Global Finite-Time Consensus of Multi-Agent Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1381-1397页

作者： Zongyu Zuo Jingchuan Tang Ruiqi ke Qing-Long han Seventh Research Division Beihang University(BUAA)Beijing 100191China School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyMelbourne VIC 3122Australia IEEE

This paper investigates the problem of global/semi-global finite-time consensus for integrator-type multi-agent *** hyperbolic tangent function-based protocols are pro-posed to achieve global and semi-global finite-time consensus for both single-integrator and double-integrator multi-agent systems with leaderless undirected and leader-following directed commu-nication *** new protocols not only provide an explicit upper-bound estimate for the settling time,but also have a user-prescribed bounded control *** addition,compared to some existing results based on the saturation function,the pro-posed approach considerably simplifies the protocol design and the stability *** examples and an application demonstrate the effectiveness of the proposed protocols.

关键词： Consensus protocol finite-time consensus hyper-bolic tangent function multi-agent systems.

Black-box membership inference attacks based on shadow model

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The Journal of China Universities of Posts and Telecommunications 2024年第4期31卷 1-16页

作者： han zhen Zhou Wen'an han Xiaoxuan Wu Jie School of Computer Science Beijing University of Posts and TelecommunicationsBeijing 100876China

Membership inference attacks on machine learning models have drawn significant *** current research primarily utilizes shadow modeling techniques,which require knowledge of the target model and training data,practical scenarios involve black-box access to the target model with no available *** training data further complicate the implementation of these *** this paper,we experimentally compare common data enhancement schemes and propose a data synthesis framework based on the variational autoencoder generative adversarial network(VAE-GAN)to extend the training data for shadow ***,this paper proposes a shadow model training algorithm based on adversarial training to improve the shadow model's ability to mimic the predicted behavior of the target model when the target model's information is *** conducting attack experiments on different models under the black-box access setting,this paper verifies the effectiveness of the VAE-GAN-based data synthesis framework for improving the accuracy of membership inference ***,we verify that the shadow model,trained by using the adversarial training approach,effectively improves the degree of mimicking the predicted behavior of the target *** with existing research methods,the method proposed in this paper achieves a 2%improvement in attack accuracy and delivers better attack performance.

关键词： machine learning membership inference attack shadow model black-box model

Improved Variable Forgetting Factor Proportionate RLS Algorithm with Sparse Penalty and Fast Implementation Using DCD Iterations

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China Communications 2024年第10期21卷 16-27页

作者： han zhen Zhang Fengrui Zhang Yu han Yanfeng Jiang Peng GNSS Research Center Wuhan UniversityWuhan 430072China School of Information Science and Technology Shijiazhuang Tiedao UniversityShijiazhuang 050043China

The proportionate recursive least squares(PRLS)algorithm has shown faster convergence and better performance than both proportionate updating(PU)mechanism based least mean squares(LMS)algorithms and RLS algorithms with a sparse regularization *** this paper,we propose a variable forgetting factor(VFF)PRLS algorithm with a sparse penalty,e.g.,l_(1)-norm,for sparse *** reduce the computation complexity of the proposed algorithm,a fast implementation method based on dichotomous coordinate descent(DCD)algorithm is also *** results indicate superior performance of the proposed algorithm.

关键词： dichotomous coordinate descent proportionate matrix RLS sparse systems variable forgetting factor

Hydration lubrication modulated by water structure at TiO2–aqueous interfaces

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Friction 2024年第4期12卷 591-605页

作者： Pingsu MA Yuan LIU ke han Yu TIAN Liran MA State key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

The nature of solid-liquid interfaces is of great significance in *** advances have been made in lubrication based on hydration ***,a detailed molecular-level understanding is still ***,we investigated water molecule behaviors at the TiO2-aqueous interfaces by the sum-frequency generation vibrational spectroscopy(SFG-VS)and atomic force microscope(AFM)to elucidate the fundamental role of solid-liquid interfaces in *** contributions of water structures and hydration effects were revealed,where water structures played the dominant role in lubrication for TiO2 surfaces of varying hydrophilicity,while hydration effects dominated with the increasing of ion *** lubrication is observed on the initial TiO2 surfaces with strongly H-bonded water molecules compared to the hydrophilic TiO2 surfaces with more disordered *** stable ordered water arrangement with strong hydrogen bonds and the shear plane occurring between the ordered water layer and subsequent water layer may play a significant role in achieving lower *** adsorbed hydrated molecules with the increasing ionic concentration perturb ordered water but lead to the enhancement of hydration effects,which is the main reason for the improved lubrication for both *** work provides more insights into the detailed molecular-level understanding of the mechanism of hydration lubrication.

关键词： hydration lubrication interfacial water structures hydration effects titanium dioxide(TiO2)