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Effects of Al8Cu4Er Phase on Corrosion Behavior of Al-Cu-Mg alloy with Er addition

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Acta Metallurgica Sinica(English Letters) 2020年第10期33卷 1379-1387页

作者： wei-ning shi Hai-Fei Zhou Xin-Fang Zhang State Key Laboratory of Advanced Metallurgy School of Metallurgical and Ecological EngineeringUniversity of Science and Technology BeijingBeijing 100083China Zhejiang Electric Power Corporation Research Institute Hangzhou 310014China

The effect of Al8Cu4Er phase on the corrosion behavior of Al-Cu-Mg alloy with rare earth Er addition in an under-aging state was studied.The results revealed that the addition Er into the Al-Cu-Mg alloy induced the formation of Al8Cu4 Er phase.The Al8Cu4Er phase can significantly refine the grains during recrystallization,thereby suppressing the continuous precipitation of S-phase at grain boundaries and improving the resistance to intergranular corrosion.Conversely,the corrosion susceptibility of local regions around the Al8Cu4Er phase with large dimension was higher than that of the AlCuFeMnSi phase,but weaker than that of θ phase,resulting in decreased pitting corrosion resistance.

关键词： Aluminum alloy Er micro-alloying Corrosion Grain boundaries Secondary phase

Effect of nonmetallic inclusions on localized corrosion of spring steel

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International Journal of Minerals,Metallurgy and Materials 2021年第3期28卷 390-397页

作者： wei-ning shi Shu-feng Yang Jing-she Li School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Certain inclusions in high-strength 60Si2Mn-Cr spring steel result in poor resistance to localized corrosion.In this work,to study the effect of inclusions on the localized corrosion behavior of spring steel,accelerated corrosion tests were performed by immersing spring steel in 3wt%FeCl_(3)solution for different times.The results show that severe corrosion occurred in areas of clustered CaS inclusions.Sulfide inclusions containing Ca and Mg induced the strongest localized corrosion susceptibility.For the case of(Ca,Mn,Mg)S inclusions,the ability to induce localized corrosion susceptibility is ranked as follows:MgS>CaS>MnS.Moreover,CaS,(Ca,Mn)S,and(Ca,Mn,Mg)S inclusions were mainly responsible for inducing environmental embrittlement.

关键词： steel localized corrosion inclusions accelerated corrosion tests

Cyber-Syndrome:Concept,Theoretical Characterization,and Control Mechanism

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Tsinghua Science and Technology 2024年第3期29卷 721-735页

作者： Feifei shi Huansheng ning Liming Chen Sahraoui Dhelim School of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083China Faculty of Computing Ulster UniversityNewtownabbeyBT370QBUK School of Computer Science University College DublinDublinD04 V1W8Ireland

The prevalence of social media and mobile computing has led to intensive user engagement in the emergent Cyber-Physical-Social-Thinking(CPST)space.However,the easy access,the lack of governance,and excessive use has generated a raft of new behaviors within CPST,which affects users’physical,social,and mental states.In this paper,we conceive the Cyber-Syndrome concept to denote the collection of cyber disorders due to excessive or problematic Cyberspace interactions based on CPST theories.Then we characterize the Cyber-Syndrome concept in terms of Maslow’s theory of Needs,from which we establish an in-depth theoretical understanding of Cyber-Syndrome from its etiology,formation,symptoms,and manifestations.Finally,we propose an entropy-based Cyber-Syndrome control mechanism for its computation and management.The goal of this study is to give new insights into this rising phenomenon and offer guidance for further research and development.

关键词： Cyber-Syndrome cyber-physical systems Cyber-Physical-Social-Thinking(CPST)space Maslow’shierarchy of Needs entropy

Motion-pressure coupled control and simulation of long-endurance capability for multicapsule stratospheric airships

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Chinese Journal of Aeronautics 2024年第6期37卷 137-150页

作者： Zhiguang shi wei HUO Zongyu ZUO School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Beijing Near Space Airship Technology Development Co. LtdBeijing 100070China

The current study focuses on the motion-pressure coupled control for a multicapsule stratospheric airship and transforms the path-tracking and heading-hold control of airships into guidance tracking with a time-varying weighted sum of longitudinal and lateral velocities by the definition of compound speed.Herein,an improved nonlinear predictive control method is provided to reduce the control energy consumption by the rolling optimization of controller parameters based on finite time intervals,ensuring infinite-time path-tracking tasks.Simultaneously,combined with the proposed cyclic regulation process of safe pressure between internal and external capsules,this study can fully reflect the force-thermal coupled rule of airships under the actions of atmospheric environment and maneuvering force,while evaluating the long-endurance capability of airships under the conditions of safe superheating and overpressure.The effectiveness of the motionpressure coupled controller was verified through numerical simulations,which can overcome the influence of environmental wind and achieve a tracking effect for the desired cruise path and compound speed.The airspeed provided during the cyclic circadian time caused the maximum superheating of the helium controlled within 30C.The helium in the internal and external capsules achieved circadian regulation.The equivalent micropore diameter of the capsule of 5 mm can achieve 55 days of long-endurance flight.The controller satisfies the requirements of cruise-flight application modes for multicapsule stratospheric airships with important engineering value.

关键词： Compound speed Nonlinear predictive control Cyclic pressure regulation Long-endurance capability Stratospheric airship

A discussion of fatigue properties of notched specimens subjected to prestressing treatment machined from FGH4097

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Chinese Journal of Aeronautics 2024年第4期37卷 508-523页

作者： Rongxi shi Dasheng wei Le HAN Shun YANG School of Energy and Power Engineering Beihang UniversityBeijing 100191China Jiangxi Research Institute Beihang UniversityNanchang 330096China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

Experimental and numerical investigations were performed to reveal the effect of prestress on the fatigue properties of FGH4097 so as to quantitatively evaluate the overspeed benefit of the disc of aeroengine. A corresponding experiment was performed to examine the effect of prestress on the fatigue life of FGH97. A complete model describing the fatigue properties of the prestressed notch specimen was proposed. After the modification of mean stress, stress gradient and prestressing treatment, the model is finally verified by fatigue test of presstressed notch specimens machined from FGH4097 with satisfactory accuracy and good engineering applicability. The new model highlights that for the variable fatigue loads, the introduction of appropriate prestress is expected to benefit to the notch specimens and certainly to the disc of aeroengine regards of their fatigue properties. Both the calculation method of fatigue life parameters and the prestress correction model are proved to have good prediction accuracy.

关键词： Turbine blisk Overspeed test Prestress Fatigue life prediction FGH4097

Atlantic blocking events in a simplified nonlinear baroclinic model for local finite-amplitude wave activity

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Atmospheric and Oceanic Science Letters 2024年第4期17卷 41-45页

作者： ning shi Bamidele Abiodun Paul Wencai Liu Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters School of Atmospheric SciencesNanjing University of Information Science and TechnologyNanjingChina Nigerian Meteorological Agency AbujaNigeria

为研究北大西洋阻高的形成机制,本文在局部有限振幅波活动(LWA)框架下进行了一系列数值实验.采用的数值模型能显式地描绘出两种重要的大气内部动力过程,即非线性纬向位涡通量和Rossby波包传播.模拟结果显示,这两种动力学过程均是形成大... 详细信息

为研究北大西洋阻高的形成机制,本文在局部有限振幅波活动(LWA)框架下进行了一系列数值实验.采用的数值模型能显式地描绘出两种重要的大气内部动力过程,即非线性纬向位涡通量和Rossby波包传播.模拟结果显示,这两种动力学过程均是形成大西洋阻高的重要机理.具体地,非线性纬向位涡通量和Rossby波包传播,分别是大西洋阻高南部和北部LWA形成的主导因子.因此,本研究综合了前人关于大西洋阻高的研究成果,为其形成机理提供了新的认识.

关键词：斜压模式局地有限振幅波活动罗斯贝波传播非线性效应

Quaternion-Based Adaptive Trajectory Tracking Control of a Rotor-Missile with Unknown Parameters Identification

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Defence Technology（防务技术） 2024年第1期31卷 375-386页

作者： Jie Zhao Zhongjiao shi Yuchen Wang wei Wang Beijing Institute of Technology Beijing 100081China

This paper investigates the adaptive trajectory tracking control problem and the unknown parameter identification problem of a class of rotor-missiles with parametric system uncertainties.First,considering the uncertainty of structural and aerodynamic parameters,the six-degree-of-freedom(6Do F) nonlinear equations describing the position and attitude dynamics of the rotor-missile are established,respectively,in the inertial and body-fixed reference frames.Next,a hierarchical adaptive trajectory tracking controller that can guarantee closed-loop stability is proposed according to the cascade characteristics of the 6Do F dynamics.Then,a memory-augmented update rule of unknown parameters is proposed by integrating all historical data of the regression matrix.As long as the finitely excited condition is satisfied,the precise identification of unknown parameters can be achieved.Finally,the validity of the proposed trajectory tracking controller and the parameter identification method is proved through Lyapunov stability theory and numerical simulations.

关键词： Rotor-missile Adaptive control Parameter identification Quaternion control

Physiotherapy for patients with depression:Recent research progress

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World Journal of Psychiatry 2024年第5期14卷 635-643页

作者： Hui-Ling Liu Jing Sun shi-Feng Meng ning Sun Department of Mental Health First Clinical Medical College of Shanxi Medical UniversityTaiyuan 030000Shanxi ProvinceChina Department of Rehabilitation First Hospital of Shanxi Medical UniversityTaiyuan 030000Shanxi ProvinceChina Department of Mental Health First Hospital of Shanxi Medical UniversityTaiyuan 030000Shanxi ProvinceChina

Depression,a common mental illness,seriously affects the health of individuals and has deleterious effects on society.The prevention and treatment of depression has drawn the attention of many researchers and has become an important social issue.The treatment strategies for depression include drugs,psychotherapy,and physiotherapy.Drug therapy is ineffective in some patients and psychotherapy has treatment limitations.As a reliable adjuvant therapy,physiotherapy compensates for the shortcomings of drug and psychotherapy and effectively reduces the disease recurrence rate.Physiotherapy is more scientific and rigorous,its methods are diverse,and to a certain extent,provides more choices for the treatment of depression.Physiotherapy can relieve symptoms in many ways,such as by improving the levels of neurobiochemical molecules,inhibiting the inflammatory response,regulating the neuroendocrine system,and increasing neuroplasticity.Physiotherapy has biological effects similar to those of antidepressants and may produce a superimposed impact when combined with other treatments.This article summarizes the findings on the use of physiotherapy to treat patients with depression over the past five years.It also discusses several methods of physiotherapy for treating depression from the aspects of clinical effect,mechanism of action,and disadvantages,thereby serving as a reference for the in-depth development of physiotherapy research.

关键词： Depression Physiotherapy Non-pharmacological Rehabilitation therapy Recent advances

Geochronological and geochemical constraints on the petrogenesis and geodynamic process of Hemler,Vlinder,and Il'ichev seamount lavas in NW Pacific

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Science China Earth Sciences 2024年第6期67卷 1856-1871页

作者： Xun wei Yan ZHANG Xuefa shi Hui ZHANG Key Laboratory of Marine Geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Marine Geology Qingdao Marine Science and Technology CenterQingdao 266237China Shandong Key Laboratory of Deep Sea Mineral Resources Development(Preparatory) Qingdao 266061China

Oceanic intraplate volcanoes with linear age progressions are usually accepted to be derived from melting of an upwelling mantle plume.Several seamount groups in NW Pacific,however,show complex age-distance relationships that are difficult to explain using the classic“mantle plume hypothesis”,and thus their origins are controversial.In this study,we present ^(40)Ar-^(39)Ar age,geochemical,and Sr-Nd-Pb-Hf isotopic data of lavas from Hemler,Vlinder,and Il’ichev seamounts in NW Pacific,to elucidate their petrogenesis and geodynamic process.The lavas from Hemler,Vlinder,and Il’ichev seamounts are classified as alkali basalt,basanite/nephelinite,and trachyte.Lavas with Mg O>8 wt.%exhibit high contents of CaO,FeO^(T),and TiO_(2),similar to the composition of melts formed from reaction between carbonated eclogite-derived melts and fertile peridotite.These lavas have elevated Zr/Hf ratios(40.6-45.2)and negative Zr and Hf anomalies,indicating the presence of a carbonate component in the mantle source.They are enriched in incompatible trace elements and have enriched mantle 1(EM1)-like SrNd-Pb-Hf isotopic compositions.The isotopic compositions of Vlinder,Il’ichev basanite,and Hemler lavas in this study are similar to the Rarotonga hotspot.Although occurring at the same seamount,the Il’ichev alkali basalts display more depleted SrNd-Hf isotopic compositions compared to Il’ichev basanite.According to plate tectonic reconstruction results,the ages of Hemler(100.1 Ma),Vlinder pre-(100.2 Ma)and post-shield(87.5 Ma),and Il’ichev(56.4 Ma)lavas clearly deviate from the Macdonald,Arago,Rarotonga,and Samoa hotspot tracks,indicating that they cannot directly originate from mantle plumes.We propose that in the mid-Cretaceous,when the Pacific plate passed over Rarotonga hotspot,melting of Rarotonga plume formed the Vlinder(main-shield stage),Pako,and Ioah seamounts.The Rarotonga(and possibly Samoa)plume materials would have been dispersed into the surrounding asthenosphere by mantle convection.These diffuse plume materials would underg

关键词： Mantle plume Magellan seamount trail Carbonated mantle component Hotspot Lithosphere extension