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Stochastic averaging of quasi partially integrable Hamiltonian systems under fractional Gaussian noise

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2017年第9期18卷 704-717页

作者： Qiang-feng LU Mao-lin DENG Wei-qiu ZHU Department of Mechanics Zhefiang University Hangzhou 310077 China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Hangzhou 310027 China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University Hangzhou 310027 China

A stochastic averaging method for predicting the response of quasi partially integrable and non-resonant Hamiltoniansystems to fractional Gaussian noise （fGla） with the Hurst index 1/2〈H〈l is proposed. The averaged stochastic differential equa-tions （SDEs） for the first integrals of the associated Hamiltonian system are derived. The dimension of averaged SDEs is less thanthat of the original system. The stationary probability density and statistics of the original system are obtained approximately fromsolving the averaged SDEs numerically. Two systems are worked out to illustrate the proposed stochastic averaging method. It isshown that the results obtained by using the proposed stochastic averaging method and those from digital simulation of originalsystem agree well, and the computational time for the former results is less than that for the latter ones.

关键词： Fractional Brownian motion (fBm) Fractional Gaussian noise (fGn) Quasi partially integrable Hamiltonian system Stochastic averaging method Stationary response

Oxidation behavior of Al0.2CoCrFeNi high-entropy alloy film in supercritical water environment

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Rare Metals 2022年第4期41卷 1217-1222页

作者： Bao-Hong zhu Hao-Chen qiu wei Jiang Qing-He Yu GRIMAT Engineering Institute Co. LtdBeijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China National Engineering Research Center of Nonferrous Metals Materials and Products for New Energy GRINM Group Co.Ltd.Beijing 100088China

The corrosion resistance of Al0.2CoCrFeNi high-entropy alloy(HEA) film deposited by magnetron sputtering was investigated and compared with that of Al0.2 CoCrFeNi HEA bulk and G115 alloy.The HEA film is composed of face-centered cubic with nanoscale grain size.The HE As(film and bulk) exhibit higher electro-chemical corrosion resistance than the G115 alloy in 3.5 wt% NaCl solution.

关键词： alloy corrosion resistance

Transient stochastic response of quasi integerable Hamiltonian systems

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Acta Mechanica Sinica 2013年第4期29卷 602-611页

作者： Zhong-Hua Liu Jian-Hua Geng Wei-qiu ZHU Department of Civil Engineering Xiamen University Department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

The approximate transient response of quasi in- tegrable Hamiltonian systems under Gaussian white noise excitations is investigated. First, the averaged It6 equa- tions for independent motion integrals and the associated Fokker-Planck-Kolmogorov （FPK） equation governing the transient probability density of independent motion integrals of the system are derived by applying the stochastic averag- ing method for quasi integrable Hamiltonian systems. Then, approximate solution of the transient probability density of independent motion integrals is obtained by applying the Galerkin method to solve the FPK equation. The approxi- mate transient solution is expressed as a series in terms of properly selected base functions with time-dependent coeffi- cients. The transient probability densities of displacements and velocities can be derived from that of independent mo- tion integrals. Three examples are given to illustrate the ap- plication of the proposed procedure. It is shown that the re- suits for the three examples obtained by using the proposed procedure agree well with those from Monte Carlo simula- tion of the original systems.

关键词： Transient response ~ Stochastic averagingmethod ~ Galerkin method ~ Quasi integrable Hamiltoniansystem

Effects of the properties of FCCS on the removing of catalyst particles from FCCS under a DC electrostatic field

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Petroleum Science 2023年第3期20卷 1885-1894页

作者： Qiang Li Qing-zhu qiu Hao Cao Hui-Zhen Yang wei-wei Xu Zhao-Zeng Liu College of New Energy China University of Petroleum(East China)QingdaoShandong 266580China

Catalytic cracking is the main method to lighten heavy crude oil,this process can produce high quality oil products such as gasoline and diesel,but also produces a large amount of fluid catalytic cracking slurry(FCCS).The catalyst particles in FCCS seriously restrict the secondary processing of FCCS and need to be removed,and the properties of Fccs is an important factor that affects the removal efficiency of the catalyst particles.Based on the"effective contact point"model proposed by the research group,this study further proposed the"electrostatic separation efficiency calculation"model.In this model,since Fccs has a uniform distribution of catalyst particles,the ratio of the number of catalyst particles can be expressed as the ratio of area to achieve the calculation of separation efficiency.Then the catalyst removal efficiency under different viscosity was analyzed,thus verifying the feasibility of this model.The effects of temperature and mass ratio of four components on the viscosity of FccS were investigated respectively,then the effects of temperature and four components'mass ratio on the electrostatic sep-aration can be directly converted into the effect of viscosity on the electrostatic separation efficiency.All the results show the electrostatic separation efficiency decreases with increasing viscosity,and the best separationtemperatureis120℃.

关键词： Fluid catalytic cracking slurry(FCCS) Separation efficiency Viscosity Temperature Four components'mass ratio

Controllable Morphology Tailoring with Solvothermal Method Toward LiMnPO_(4)/C Cathode Materials for Improved Performance and Favorable Thermostability

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Acta Metallurgica Sinica(English Letters) 2022年第5期35卷 790-800页

作者： wei Yang Xiulian qiu Chengyun Wang Jinhao Ye Jihua zhu Hanbo Zou Shengzhou Chen School of Chemistry and Chemical Engineering Guangzhou UniversityGuangzhou510006China GAC Automotive Research and Development Center Guangzhou511434China Sunwoda Electronics Co. LtdShenzhen518107China

An environmentally friendly method for the synthesis of LiMnPO_(4)/C anode material for lithium-ion batteries by solvothermal method is introduced.The modification of the morphology of this precursor is altered by changing the ratio of the conditioning solvent(water-ethylene glycol solution)and the order of material addition.Ethylene glycol(EG)exerts a considerable influence on synthesizing LiMnPO_(4)/C flake-like nanocrystal,which benefits the extraction/insertion reaction of lithium ions and improves the electrochemical activity and electrochemical performance of LiMnPO_(4)/C material.When the solvent composition is H_(2)O:EG=1:3,exhibiting exceptional charge/discharge performance and rate capability,the specific discharge capacities are 155.8,153.7,148.8,141.4,129.5,and 112.6 mAh g^(−1) at the 0.1,0.2,0.5,1,2,and 5 C rates,respectively.When the charge-discharge rate returns to 0.1 C,the LiMnPO_(4)/C material shows a reversible discharge specific capacity of 153.7 mAh g^(−1).Differential scanning calorimetry(DSC)tests verify that the thermodynamic stability of the prepared LiMnPO_(4)/C(LMP)and commercial LiFePO_(4)(LFP)materials is better than that of commercial nickel-cobalt-aluminum(NCA)ternary materials.These prepared LiMnPO_(4)/C composites have high electrochemical capacity and cycle stability.

关键词： LiMnPO_(4)/C solvothermal method Ethylene glycol Lithium-ion diffusion Thermostability

Electroacupuncture Attenuates Immune-Inflammatory Response in Hippocampus of Rats with Vascular Dementia by Inhibiting TLR4/MyD88 Signaling Pathway

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Chinese Journal of Integrative Medicine 2022年第2期28卷 153-161页

作者： BU Yu LI Wen-shuang LIN Ji wei Yu-wei SUN qiu-ying zhu Shi-jie TANG Zhong-sheng School of Basic Medicine Guizhou University of Traditional Chinese MedicineGuiyang(550025)China Department of Hematology the Second Affiliated Hospital of Guizhou University of Traditional Chinese MedicineGuiyang(550025)China

Objective:To investigate whether electroacupuncture(EA)alleviates cognitive impairment by suppressing the toll-like receptor 4(TLR4)/myeloid differentiation factor 88(MyD88)signaling pathway,which triggers immune-inflammatory responses in the hippocampus of rats with vascular dementia(VaD).Methods:The experiments were conducted in 3 parts and in total the Sprague-Dawley rats were randomly divided into 8 groups by a random number table,including sham,four-vessel occlusion(4-VO),4-VO+EA,4-VO+non-EA,sham+EA,4-VO+lipopolysaccharide(LPS),4-VO+LPS+EA,and 4-VO+TAK-242 groups.The VaD model was established by the 4-VO method.Seven days later,rats were treated with EA at 5 acupoints of Baihui(DV 20),Danzhong(RN 17),Geshu(BL 17),Qihai(RN 6)and Sanyinjiao(SP 6),once per day for 3 consecutive weeks.Lymphocyte subsets,lymphocyte transformation rates,and inflammatory cytokines interleukin-6(IL-6)and tumor necrosis factorα(TNF-α)were measured to assess immune function and inflammation in VaD rats.Transmission electron microscopy was used to observe the ultrastructure of nerve cells in the hippocampus.The levels of TLR4,MyD88,IL-6,and TNF-αwere detected after EA treatment.TLR4/MyD88 signaling and cognitive function were also assessed after intracerebroventricular injection of TLR4 antagonist TAK-242 or TLR4 agonist LPS with or without EA.Results:Compared with the 4-VO group,EA notably improved immune function of rats in the 4-VO+EA group,inhibited the protein and mRNA expressions of TLR4 and MyD88 in the hippocampus of rats,reduced the expressions of serum IL-6 and TNF-α(all P0.05).Conclusions:EA attenuated cognitive impairment associated with immune inflammation by inhibition of the TLR4/MyD88 signaling pathway.Thus,EA may be a promising alternative therapy for the treatment of VaD.

关键词： electroacupuncture vascular dementia immune-inflammation toll-like receptor 4/myeloid differentiation factor 88 signaling pathway

Construction of CoNi_(2)S_(4) nanocubes interlinked by few-layer Ti_(3)C_(2)T_(x) MXene with high performance for asymmetric supercapacitors

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Rare Metals 2022年第12期41卷 4116-4126页

作者： Ji-qiu Qi Meng-Yuan Huang Chen-Ya Ruan Dong-Dong zhu Lei zhu Fu-Xiang wei Yan-wei Sui Qing-Kun Meng Jiangsu Province Engineering Laboratory of High Efficient Energy Storage Technology and Equipments School of Materials Science and PhysicsChina University of Mining and TechnologyXuzhou 221116China Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province Quzhou UniversityQuzhou 324000China

Both MXene and zeolitic imidazolate framework(ZIF)derivatives are tend to agglomerate during the compound process,which adversely affects their electrochemical properties.To alleviate this phenomenon,fewlayer MXene was stripped by mechanical method,and electrostatic self-assembly with ZIF-67 in the presence of cationic surfactants.Furthermore,CoNi_(2)S_(4)/MXene composite was synthesized by the facile hydrothermal reaction.CoNi_(2)S_(4)well retained the cube frame structure of the ZIF-67 with the sagging outer frame and rough surface.In the composite,CoNi_(2)S_(4)nanocubes were interlinked by MXene nanosheets,which can effectively improve the structural stability and make full use of the active surface.CoNi_(2)S_(4)/MXene composite electrode exhibits an outperforming specific capacitance(751 C·g^(-1)at 1 A·g^(-1)),far higher than that of pure CoNi2S4(600 C·g^(-1)at 1 A·g^(-1)).An asymmetric supercapacitor(CoNi_(2)S_(4)/MXene//reduced graphene oxide(RGO))assembling delivers high energy density of 33.8 Wh·kg^(-1)and excellent cycling performance.This study indicates the potential of MXene/ZIF derivatives in the application of supercapacitor.

关键词： Cubic frame structure Few-layer MXene ZIF-67 Asymmetric supercapacitor

Stochastic optimal control of cable vibration in plane by using axial support motion

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Acta Mechanica Sinica 2011年第4期27卷 578-586页

作者： Ming Zhao Wei-qiu ZHU Department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University 310027 Hangzhou China

A stochastic optimal control strategy for a slightly sagged cable using support motion in the cable axial direction is proposed. The nonlinear equation of cable motion in plane is derived and reduced to the equations for the first two modes of cable vibration by using the Galerkin method. The partially averaged Ito equation for controlled system energy is further derived by applying the stochastic averaging method for quasi-non-integrable Hamiltonian systems. The dynamical programming equation for the controlled system energy with a performance index is established by applying the stochastic dynamical programming principle and a stochastic optimal control law is obtained through solving the dynamical programming equation. A bilinear controller by using the direct method of Lyapunov is introduced. The comparison between the two controllers shows that the proposed stochastic optimal control strategy is superior to the bilinear control strategy in terms of higher control effectiveness and efficiency.

关键词： Stay cable Active control - Stochastic optimalcontrol Dynamical programming principle

Clinical practice guidelines for pregnancy-associated breast cancer:Chinese society of breast surgery(CSBrS)practice guidelines 2021

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Chinese Medical Journal 2021年第20期134卷 2395-2397页

作者： Qing Chen Yi-Ran qiu Ming-Di Zhang wei zhu wei-Rong Gu Ke-Jin Wu Department of Breast Surgery Obstetrics and Gynecology Hospital of Fudan UniversityShanghai 200011China Shanghai Medical College Fudan UniversityShanghai 200032China Department of General Surgery Zhongshan Hospital of Fudan UniversityShanghai 200032China Department of Obstetrics Obstetrics and Gynecology Hospital of Fudan UniversityShanghai 200011China

Pregnancy-associated breast cancer(PABC),including breast cancer during pregnancy(BCP)and postpartum breast cancer(PBC),has become a critical issue for clinicians in consideration of both maternal and offspring safety during diagnosis and treatment.The recommendations in this guideline are mainly based on currently available high-quality prospective studies,retrospective cohort studies,meta-analyses,and guidelines and consensus documents published by internationally recognized or national societies or associations.Clinicians should carefully analyze the potential benefits and risks of each treatment before recommending whether to terminate the pregnancy or lactation,balance the advantages and disadvantages of the treatments,and respect the wishes of patients.

关键词： pregnancy diagnosis treatment