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SUPERCONVERGENCE AND A POSTERIORI ERROR ESTIMATES FOR BOUNDARY CONTROL GOVERNED BY STOKES EQUATIONS

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Journal of Computational Mathematics 2006年第3期24卷 343-356页

作者： Hui-po liu ning-ning Yan Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

In this paper, the superconvergence results are derived for a class of boundary control problems governed by Stokes equations. We derive superconvergence results for both the control and the state approximation. Base ... 详细信息

关键词： Boundary control Finite element method Superconvergence A posteriori error estimates.

Network selection policy in multi-radio access environment using stochastic control theory

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The Journal of China Universities of Posts and Telecommunications 2011年第4期18卷 98-103页

作者： WEI Yi-fei SONG Mei ZHANG Yong liu ning-ning School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

Network selection is crucial in improving the performance of heterogeneous wireless access systems. Most of previous work on network selection or radio resource allocation concentrates on the capability of each available network and ignores the time-varying nature of wireless media due to channel fading. However, the channel condition determines the state of each wireless network and plays a vital role in ensuring quality of service in multi-radio access environment. In this article, we propose a network selection policy using stochastic control theory considering the time-varying and stochastic character of wireless channels. The proposed scheme selects one network among different alternatives in each decision epoch according to the channel state of each network, which is modeled as finite-state Markov channel, with the objectives of increasing the data-rate, decreasing the bit error rate and minishing the delay. The procedure of network selection is formulated as a stochastic control problem, which can be solved using linear programming and primal-dual index heuristic algorithm. Simulation results are presented to show that network selection has great impact on the system performance, and the proposed scheme can improve the performance significantly.

关键词： network selection multi-radio finite-state Markov channel stochastic control

ODF1在胃肠道神经内分泌肿瘤中的表达及临床意义

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诊断病理学杂志 2024年第1期31卷 34-37页

作者：李新军刘敏李柏成刘蒙蒙刘宁宁山东省滨州市人民医院病理科山东滨州256600 山东省滨州市人民医院心内科山东滨州256600

目的探讨ODF1在胃肠道神经内分泌肿瘤(NEN)中的表达及与临床病理特征和预后的关系。方法收集2008-01—2021-12;胃肠道NEN标本254例,包括168例神经内分泌瘤(NETs)和86例神经内分泌癌(NEC)。采用免疫组化法检测ODF1在上述组织中的表达,分... 详细信息

目的探讨ODF1在胃肠道神经内分泌肿瘤(NEN)中的表达及与临床病理特征和预后的关系。方法收集2008-01—2021-12;胃肠道NEN标本254例,包括168例神经内分泌瘤(NETs)和86例神经内分泌癌(NEC)。采用免疫组化法检测ODF1在上述组织中的表达,分析其与临床病理特征和预后的关系。结果ODF1在168例NETs中全部弥漫阳性表达,在86例NEC中的阳性表达率为24.4%,而且均为局灶阳性染色。ODF1在胃肠道NETs和NEC中的表达差异有统计学意义(P0.05)。Kaplan-Meier生存分析和单因素COX分析显示ODF1阳性NEC患者的预后较好,多因素COX分析显示ODF1表达不是NEC独立的预后因子。结论ODF1在胃肠道NETs中表达显著高于NEC。ODF1水平随着NEN分级增高、T分期增加、淋巴结转移和TNM分期增加而降低,对预后预测有一定价值。

关键词：神经内分泌肿瘤胃肠道精子尾部外周致密纤维1 免疫组化预后

PSR J1614-2230 May Include Hyperons

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Chinese Physics Letters 2011年第8期28卷 352-355页

作者： YU Zi DING Wen-Bo BAO Tmurbagan liu ning-ning The College of Science Nanjing Forestry UniversityNanjing 210037 Department of Physics Bohai UniversityJinzhou 121000 College of Physics and Electronic Engineering Nanyang Normal UniversityNanyang 473061 Department of Basic Course Nanjing Institute of TechnologyNanjing 211167

In the framework of the relativistic mean field theory,it is found that recently discovered PSR J1614-2230 with mass of 1.97±0.04Mʘmay include hyperons when the weakly interacting light boson(WILB)is *** describe PSR J1614−2230 with the equation of state(EOS)including hyperons,the characteristic scale of the WILB(g^(2)/μ^(2))should lie in the range of 13–46(24–46)GeV^(−2) with the weak(strong)hyperon-hyperon(YY)*** measurements of inertial momentum and the total neutrino luminosity of the neutron star could be used to further constrain the characteristic scale of the *** more stringent constraint on the WILB is given,the mass measurement of the neutron star could not exclude any soft EOS.

关键词： interaction weakly momentum

PPB structure elimination,DRX nucleation mechanisms and grain growth behavior of the3rd-generation PM superalloy for manufacturing aviation components

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Chinese Journal of Aeronautics 2024年第1期37卷 325-344页

作者： Baoyun ZHANG Yongquan ning Zhaotian WANG Qiaomu liu School of Materials Science and Engineering Northwestern Polytechnical UniversityXi’an 710072China AECC Sichuan Gas Turbine Establishment Chengdu 610500China

Previous Particle Boundary(PPB),as the detrimental structure in Powder Metallurgy(PM)components,should be eliminated by subsequent hot process to improve the mechanical *** objective is to investigate the Dynamic Recrystallization(DRX)nucleation mechanisms and grain growth behavior of the 3rd-generation PM superalloy with PPB *** observation reveals that PPB decorated with(Ti,Ta,Nb)C carbides belongs to the discontinuous chain-like *** elimination of PPB networks can be achieved effectively via hot deformation due to the occurrence of *** different DRX nucleation mechanisms were proposed and discussed in detail according to the special microstructure characteristics of the PM ***,local lattice rotations can be detected in the vicinity of(Ti,Ta,Nb)C carbides during hot deformation and thus PPB structure serves as the preferential nucleation sites for DRX grains via Particle-Stimulated Nucleation(PSN).Then,Discontinuous-DRX(DDRX)characterized by grain boundary bulging dominates the microstructure refinement and Continuous-DRX(CDRX)operated by subgrain rotation can be regarded as an important assistant *** last,the initial Σ3 boundaries would lose their twin characteristics owing to the crystal rotation and then transform into the general High Angle Grain Boundaries(HAGBs).The distorted twins provide additional DRX nucleation sites,viz.,twin-assisted *** attention was focused on the grain growth behavior of the PM superalloy in subsequent annealing *** recrystallization temperature was determined to be about 1110.C and 1140.C can be considered as the critical temperature for grain *** findings would provide theoretical support for microstructure refinement of the 3rd-generation PM superalloy,which is of pivotal significance for improving the mechanical properties of aviation components.

关键词： PM superalloy Previous Particle Boundary(PPB) DRX nucleation Grain growth Microstructure refinement

Effects of orientation on the fatigue crack growth behaviors of the ZK60 magnesium alloy in air and PBS

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Journal of Magnesium and Alloys 2024年第1期12卷 281-294页

作者： Jiaqi Hu Zheng liu Zuoliang ning Hong Gao School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology Tianjin 300072China

Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium *** investigate the influences of specimen orientation,the corrosion tests and(corrosion)fatigue crack growth tests were *** rolled and transverse surfaces of the materials show distinct corrosion rate differences in the stable corrosion stage,but the truth is the opposite for the initial stage of *** air,specimen orientations have a significant influence on the plastic deformation mechanisms near the crack tip,which results in different fatigue fracture surfaces and cracking *** with R-T specimens,N-T specimens show a slower fatigue crack growth(FCG)rate in air,which can be attributed to crack closure effects and deformation twinning near the crack *** corrosion environment will not significantly change the main plastic deformation mechanisms for the same type of ***,the FCG rate in phosphate buffer saline(PBS)is one order of magnitude higher than that in air,which is caused by the combined effects of hydrogen-induced cracking and anodic *** to the similar corrosion rates at crack tips,the specimens with different orientations display close FCG rates in PBS.

关键词： Magnesium alloy Orientation Corrosion Fatigue crack growth

Adaptive Observer-Based Finite-Time Fault Tolerant Control for Non-Strict Feedback Systems

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Journal of Systems Science & Complexity 2024年第4期37卷 1526-1544页

作者： SHENG ning liu Yang CHI Ronghu AI Zidong College of Automation and Electronic Engineering Qingdao University of Science and TechnologyQingdao 266042China

This paper considers the adaptive finite-time control and observer design method for a class of non-strict feedback systems with unmeasurable states,unknown nonlinear dynamics and actuator *** this paper,an observer is proposed to estimate the unmeasurable states in finite-time based on adaptive technique and neural networks,while the actuator faults are not *** filter is used to solve the computational explosion and singularity problems caused by the traditional backstepping and non-strict feedback structure,*** the fault efficiency indicators in real systems are not available,two-layer neural networks are adopted,where the first network is to estimate the unknown nonlinearities of systems and the second one is to estimate fault efficiency indicators and unknown nonlinear *** proposed scheme guarantees that states are bounded through stability ***,two experiments including a numerical example and a spring-mass-damper system are given to verify the effectiveness of the proposed method.

关键词： Command filter fault tolerant control finite-time control non-strict systems two-layer neural networks

Improvement of the piezoelectricity of PVDF-HFP by CoFe_(2)O_(4)nanoparticles

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Nano Materials Science 2024年第2期6卷 201-210页

作者： Dan Lei ning Hu Liangke Wu Alamusi Huiming ning Yang Wang Zhaonan Jin Yaolu liu College of Aerospace Engineering Chongqing UniversityChongqing400044China State Key Laboratory of Reliability and Intelligence Electrical Equipment School of Mechanical EngineeringHebei University of TechnologyTianjin300401China

High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method accompanied by uniaxial stretching and high electric field *** decisive effect of the poling electric field on the power generating capability was confirmed by the *** pure PVDF-HFP films,when the maximum electric field Emax is 120 MV/m,the calibrated open circuit voltage reaches 2.93 V,which is much higher than those poled at lower electric fields(70 MV/m:1.41 V;90 MV/m:2.11 V).Furthermore,the addition of CoFe_(2)O_(4)also influences the piezoelectricity *** the samples containing 0.15 wt%CoFe_(2)O_(4),the calibrated open circuit voltage increases to the maximum value of 3.57 ***,the relative fraction of theβ-phase and the crystallinity degree are 99%and 48%,*** effects of CoFe_(2)O_(4)nanoparticles on initial crystallization,uniaxial stretching and high electric field poling are investigated by XRD,FTIR and DSC.

关键词： PVDF-HFP CoFe_(2)O_(4)nanoparticles Piezoelectricity Nanocomposite

1.42-fold enhancement of formate selectivity by linker conversion on the Zn-based metal organic framework catalyst

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Journal of Energy Chemistry 2024年第3期90卷 183-190,I0006页

作者： Yayu Guan Yuyu liu Fanghua ning Jin Yi Jiujun Zhang Institute for Sustainable Energy College of SciencesShanghai UniversityShanghai 200444China

Electro-reduction of carbon dioxide(ERCO_(2)) is considered an effective method to alleviate the greenhouse effect and produce value-added *** the dominant selectivity of Zn-based catalysts for formate remains a *** this article,the ZnIn-E_(12) catalyst is successfully prepared by solvent assisted ligand exchange(SALE) method to convert organic ligands,achieving a Faradaic efficiency of 72.28% for formate at-1.26 V ***(V_(RHE)),which is 1.42 times higher than the original *** shows that the successful conversion of organic ligands can transform the catalyst from the original large size polyhedron to cross-linked network of particles with a diameter of about 30 *** increased specific surface area can expose more active sites and facilitate the electrocatalytic conversion of CO_(2) to *** work is expected to provide inspiration for the regulation of formate selectivity and catalyst size in Zn-based catalysts.

关键词： Electrocatalyst Carbon dioxide Formate Linker conversion