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Influence of multi-stage heat treatment on the microstructure and mechanical properties of TC21 titanium alloy

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International Journal of Minerals,Metallurgy and Materials 2021年第2期28卷 296-304页

作者： Wei Long Song Zhang Yi-long Liang Mei-gui Ou College of Materials and Metallurgy Guizhou UniversityGuiyang 550025China Key Laboratory for Materials Structure and Strength of Guizhou province Guizhou UniversityGuiyang 550025China National Local Joint Engineering Laboratory for High Performance Metal Structure Materials and Manufacturing Technology Guizhou UniversityGuiyang 550025China

Duplex-structured TC21 alloy samples were first solution-treated at a higher temperature in theα+βregion(940°C)with furnace cooling(FC),air cooling(AC),and water cooling(WC),followed by a second-stage solution treatment at a lower temperature in theα+βregion(900°C),and then finally aged at 590°C.The effects of the morphology and quantity ofαphases on the structure and properties of the TC21 alloy after the different heat treatments were analyzed.The in-situ tensile deformation process and crack propagation behavior were observed using scanning electron microscopy(SEM).The quantity of equiaxedαphases as well as the thickness of lamellarαphases reduced,the tensile strength increased firstly and then decreased,the elongation decreased with the increasing cooling rate after the first-stage solution treatment.The amount and size of lamellarαphases increased after the second-stage solution treatment because of sufficient diffusion of the alloying elements,thereby leading to increased tensile strength.The amount of dispersedαphases increased after the third-stage aging treatment owing to the increase in the nucleation rate,resulting in a noteworthy strengthening effect.After the third-stage aging treatment,the first-stage FC sample exhibited better mechanical properties because it contained more equiaxedαandβtrans phases than the first-stage AC and WC samples.

关键词： multi-stage heat treatment titanium alloy in-situ tension microstructure mechanical properties

Almost Periodic Type Group Actions on Compact Quantum Metric Spaces

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Acta Mathematica Sinica,English Series 2024年第2期40卷 568-594页

作者： Bo Tao long wei WU College of Mathematics MIIT Key Laboratory of Mathematical Modelling and High Performance Computing of Air VehiclesNanjing University of Aeronautics and AstronauticsNanjing 211106P.R.China School of Mathematical Sciences Shanghai Key Laboratory of Pure Mathematics and Mathematical PracticeEast China Normal UniversityShanghai 200241P.R.China

A compact quantum metric space is a complete order unit space A endowed with a Lipnorm L.We give some characterizations of almost periodic type group actions on a compact quantum metric space(A,L)by means of several kinds of subsets of A,its induced equicontinuous actions on several important subsets of the dual Banach space A*,and the Lip-norm L with its induced metric space structures on the state space S(A)of A.

关键词： Lip-norm compact quantum metric space Lipschitz isomorphism almost periodicity Arzela-Ascoli theorem metric set

Nodal solutions for fractional Schrodinger-Poisson problems

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Science China Mathematics 2020年第11期63卷 2267-2286页

作者： Wei Long Jianfu Yang weilin Yu College of Mathematics and Information Science Jiangxi Normal UniversityNanchang 330022China

In this paper,we consider the following fractional Schrodinger-Poisson problem:{ε^2s(-Δ)^su+V(x)u+φu=|u|^p-1u,x∈R^N,(-Δ)^tφ=u^2,x∈R^N,where ε>0 is a small parameter,N≥3 and V(x)is a potential function.We construct non-radial sign-changing solutions,whose components may have spikes clustering at the local minimum point of V(x).

关键词： multipeak solutions fractional Schrodinger-Poisson system reduction method

Effect of Interface Area on Nonlinear Magnetoelectric Resonance Response of Layered Multiferroic Composite Ring

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Acta Mechanica Solida Sinica 2022年第5期35卷 765-774页

作者： Jingyi Liu Lianchun long wei Li Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing100124China

Multiferroic composite structures are widely used in sensing,driving and communication.The study of their magnetoelectric(ME)behavior under various excitations is crucial.This study investigates the nonlinear ME influence of a multilayer composite ring structure consisting of Terfenol-D(TD)magnetostrictive and lead zirconate titanate(PZT)piezoelectric rings utilizing a multiphysics field modeling framework based on the fully coupled finite element method.The ME coupling coefficient of the PZT/TD concentric composite ring is predicted using the linear piezoelectric constitutive model and the nonlinear magnetostrictive constitutive model,which is congruent to the experimental data.The effect of the interface area of a trilayered structure on the coupling performance at the resonant frequency is investigated,considering the magnitude and frequency of the magnetic field and keeping the material ratio constant.The ME coupling coefficient of a trilayered structure is larger than that of a bilayered structure with the same material ratio,and the maximum ME coupling coefficient of a trilayered structure increases nonlinearly with the increase in the interface area.At the resonant frequency,the structure's ME coupling performance is considerably improved.An optimization technique based on structural geometric design and magnetic field control is presented to optimize the ME coupling coefficient.

关键词： Composite multiferroics Magnetoelectric coupling Finite element simulation Interface area Frequency

Infinitely many dichotomous solutions for the Schr?dinger-Poisson system

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Science China Mathematics 2024年

作者： Yuke He Benniao Li Wei Long School of Mathematics and Statistics and Jiangxi Provincial Center for Applied Mathematics Jiangxi Normal University

In this paper, we consider the following Schr?dinger-Poisson system ■ where ε is a small parameter, 1

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Overestimate of remediation efficiency due to residual sodium persulfate in PAHs contaminated soil and a solution

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Journal of Environmental Sciences 2022年第3期34卷 242-250页

作者： Liping He Jianhao Tong Yuanqiang Yang Jianxun Wu Linqian Li Zhonghua wei Wei Long Jingli Pang Jiyan Shi Yunnan Research Academy of Eco-environmental Sciences Kunming 650034China Department of Environmental Engineering College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China Beijing Construction Engineering Group Environmental Remediation Co.Ltd. Beijing 100015China

Oxidation remediation is a commonly used technology for PAHs contaminated soil presently,but the overestimate of efficiency due to ongoing remediation by residual oxidants during extraction and testing has not been paid enough attention.In this study,persulfate was activated by Fe(Ⅱ)to investigate the effects of residual oxidants on PAHs removal during detection process and the elimination effects of adding Na_(2)SO_(3) and extending sampling time on residual oxidants.Results verified that the residual oxidants removed PAHs in extraction process,making the results lower than the actual values:the detection recovery rate η of ΣPAHs and 3-6 ring PAHs ranged from 24.3%(25%Na_(2)S_(2)O_(8)treatment)to 87.4%(5%Na_(2)S_(2)O_(8)+4/4Fe^(2+) treatment),20.1%-99.0%,28.9%-87.9%,20.8%-89.4%,and 1.8.6%-76.9%,respectively.After adding Na_(2)SO_(3),the accuracy of detection results increased significantly:the η of ΣPAHs and 3-6 ring PAHs increased to 64.1%-96.5%,58.8%-95.5%,73.8%-114.4%,60.6%-95.6%,and 45.4%-77.1%,respectively.After 49 days of adding oxidants,residual oxidants had no considerable effect on the detection of PAHs,indicating it was appropriate to start soil remediation verification sampling49 days after the remediation was completed.The observed results will help scientific evaluation of the remediation effects of chemical oxidation on or-ganic contaminated soil.

关键词： Persulfate activation Soil remediation Polycyclic aromatic hydrocarbons Residual oxidant removal

Inhibition of Eukaryotic Initiating Factor eIF4E Overcomes Abemaciclib Resistance in Gastric Cancer

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Current Medical Science 2023年第5期43卷 927-934页

作者： Huo-long ZHA wei CHEN wei SHI Ying-ying LIAO Department of Gastroenterology Renmin HospitalHubei University of MedicineShiyan 442000China Department of Critical Care Medicine Taihe HospitalHubei University of MedicineShiyan 442000China

Objective Aberrant activating mutations in cyclin-dependent kinases 4 and 6(CDK4/6)are common in various cancers,including gastroesophageal malignancies.Although CDK4/6 inhibitors,such as abemaciclib and palbociclib,have been approved for breast cancer treatment,their effectiveness as a monotherapy remains limited for gastroesophageal tumors.The present study explored the underlying mechanism of abemaciclib resistance.Methods Abemaciclib-resistant gastric cancer cell lines were generated,and the phospho-eukaryotic translation initiation factor 4E(p-eIF4E)and eIF4E expression was compared between resistant and parental cell lines.In order to analyze the role of eIF4E in cell resistance,siRNA knockdown was employed.The effectiveness of ribavirin alone and its combination with abemaciclib was evaluated in the gastric cancer xenograft mouse model.Results The upregulation of eIF4E was a common feature in gastric cancer cells exposed to prolonged abemaciclib treatment.Gastric cancer cells with increased eIF4E levels exhibited a better response to eIF4E inhibition,especially those that were resistant to abemaciclib.Ribavirin,which is an approved anti-viral drug,significantly improved the efficacy of abemaciclib,both in vitro and in vivo,by inhibiting eIF4E.Importantly,ribavirin effectively suppressed the abemaciclib-resistant gastric cancer growth in mice without causing toxicity.Conclusion These findings suggest that targeting eIF4E can enhance the abemaciclib treatment for gastric cancer,proposing the potential combination therapy of CDK4/6 inhibitors with ribavirin for advanced gastric cancer.

关键词： eIF4E CDK4/6 ribavirin gastric cancer resistance

Twisted bounded-dilation group C*-algebras as C*-metric algebras

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Science China Mathematics 2021年第3期64卷 547-572页

作者： Botao long wei Wu Research Center for Operator Algebras East China Normal UniversityShanghai 200241China School of Mathematical Sciences Shanghai Key Laboratory of Pure Mathematics and Mathematical PracticeEast China Normal UniversityShanghai 200241China

We construct a class of C*-metric algebras. We prove that for a discrete group Γ with a 2-cocycle σ,the closure of the seminorm ||[Ml1,·]|| on Cc(Γ, σ) is a Leibniz Lip-norm on the twisted reduced group C*-algebra C*r(Γ, σ) for the pointwise multiplication operator Mlon l2(Γ), induced by a proper length function l on Γ with the property of bounded θ-dilation. Moreover, the compact quantum metric space structures depend only on the cohomology class of 2-cocycles in the Lipschitz isometric sense.

关键词： discrete group boundedθ-dilation twisted reduced group C*-algebra C*-metric algebra Leibniz Lip-norm compact quantum metric space

Bulk-boundary-transport correspondence of the second-order topological insulators

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Science China(Physics,Mechanics & Astronomy) 2023年第12期66卷 169-175页

作者： Yuxiong long Miaomiao wei Fuming Xu Jian Wang College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Department of Physics The University of Hong KongHong Kong 999077China Department of Physics University of Science and Technology of ChinaHefei 230026China

The bulk-boundary correspondence of the second-order topological insulator(SOTI)has been well established,but a universal transport signature for open systems is still absent.For a variety of SOTIs induced by applying in-plane magnetic fields in Z2-invariant first-order TIs,rotating this magnetic field features the spin pump mechanism while maintaining the SOTI phase.We demonstrate that,this spin pump can generate quantized pure spin current when tuning the magnetic field strength,which corresponds to the formation of topological corner states characterizing SOTI in two-dimensional(2D)systems.Quantized spin pump is discovered in various 2D and 3D SOTI models evolved from Z2-invariant TIs,which is robust against disorder and universally independent of system parameters including Fermi energy,system size,magnetic field strength,and pumping frequency.These findings suggest that this universal quantized spin pump can characterize the bulk-boundary-transport correspondence of SOTIs.Quantized spin pump can also be realized by combining pseudo spin such as the orbital degree of freedom with the rotating magnetic field,which could be achieved in higher-order photonic or acoustic topological systems.Such a quantized spin pump is promising as an accurate and stable single-spin source.

关键词： second-order topological insulator quantized spin pump bulk-boundary-transport correspondence