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STRONG CONVERGENCE OF A FULLY DISCRETE FINITE ELEMENT METHOD FOR A CLASS OF SEMIliNEAR STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS WITH MULTIPliCATIVE NOISE

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Journal of Computational Mathematics 2021年第4期39卷 574-598页

作者： Xiaobing Feng yukun li Yi Zhang Department of Mathematics The University of TennesseeKnoxvilleTN 37996USA Department of Mathematics University of Central FloridaOrlandoFL 32816USA Department of Mathematics and Statistics The University of North Carolina at GreensboroGreensboroNC 27402USA

This paper develops and analyzes a fully discrete finite element method for a class of semilinear stochastic partial differential equations(SPDEs)with multiplicative *** nonlinearity in the diffusion term of the SPDEs is assumed to be globally lipschitz and the nonlinearity in the drift term is only assumed to satisfy a one-sided lipschitz *** assumptions are the same ones as the cases where numerical methods for general nonlinear stochastic ordinary differential equations(SODEs)under“minimum assumptions”were *** a result,the semilinear SPDEs considered in this paper are a direct generalization of these nonlinear *** are several difficulties which need to be overcome for this ***,obviously the spatial discretization,which does not appear in the SODE case,adds an extra layer of *** turns out a spatial discretization must be designed to guarantee certain properties for the numerical scheme and its stiffness *** this paper we use a finite element interpolation technique to discretize the nonlinear drift ***,in order to prove the strong convergence of the proposed fully discrete finite element method,stability estimates for higher order moments of the H1-seminorm of the numerical solution must be established,which are difficult and delicate.A judicious combination of the properties of the drift and diffusion terms and some nontrivial techniques is used in this paper to achieve the ***,stability estimates for the second and higher order moments of the L^(2)-norm of the numerical solution are also difficult to obtain due to the fact that the mass matrix may not be diagonally *** is done by utilizing the interpolation theory and the higher moment estimates for the H1-seminorm of the numerical *** overcoming these difficulties,it is proved that the proposed fully discrete finite element method is convergent in strong norms with nearly optimal rates of ***

关键词： Stochastic partial differential equations One-sided lipschitz Strong convergence

Bead-like cobalt-nitrogen co-doped carbon nanocage/carbon nanofiber composite:A high-performance oxygen reduction electrocatalyst for zinc-air batteries

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Nano Research 2023年第1期16卷 545-554页

作者： Bo Zhang Yige Zhao Lu li yukun li Jin Zhang Guosheng Shao Peng Zhang State Center for International Cooperation on Designer Low-carbon and Environmental Materials(CDLCEM) School of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450001China State Key Laboratory of Chemical Resource Engineering Beijing Key Laboratory of Electrochemical Process and Technology for MaterialsBeijing University of Chemical TechnologyBeijing 100029China

Proper regulation of metal-nitrogen carbon(M-N-C)materials derived from zeolitic imidazolate frameworks(ZIFs)is essential to enhance the oxygen reduction reaction(ORR)***,most of the reports focus on the component regulation,and the structure regulation of ZIFs-derived M-N-C materials by a simple preparation method has been barely ***,using a one-step electrospinning method with subsequent pyrolysis,we have prepared a bead-like cobalt-nitrogen co-doped carbon nanocage/carbon nanofiber(Co-N-C/CNF)composite electrocatalyst with the porous carbon nanocages arranged one by one in the highly conductive carbon *** from the fully exposed active sites and improved conductivity,the Co-NC/CNF catalyst exhibits an excellent ORR performance even surpassing the commercial Pt/C *** functional theory(DFT)results demonstrate that the CoNP-N1-C2 active sites on Co-N-C/CNF make the core contribution to the improvement of ORR ***,the zinc-air battery(ZAB)based on the Co-N-C/CNF catalyst also shows outstanding discharge *** study provides a new strategy for the preparation and structural design for ZIFs-derived M-N-C materials as efficient ORR catalysts.

关键词： bead-like structure carbon nanocages electrospinning technology oxygen reduction reaction zinc−air battery

Development of microstructural inhomogeneity in multi-pass flow forming of TA15 alloy cylindrical parts

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Chinese Journal of Aeronautics 2020年第7期33卷 2088-2097页

作者： Xianxian WANG Pengfei GAO Mei ZHAN Ke YANG Yunda DONG yukun li State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming Technology and EquipmentSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710072China

Revealing the development of microstructural inhomogeneity in the multi-pass flow forming of titanium alloy components is of great significance to the microstructure control and property *** this end,the microstructural inhomogeneity of TA15 alloy spun cylindrical parts was analyzed based on the deformation *** results indicate that the material underwent significant compressive strain in the normal direction(ND),tension strain in the rolling and circumferential directions(RD and CD),while tension strain in the CD is slightly small due to the limited material flow in this *** strain characteristics make the microstructure,especially the primary a(ap),present different morphologies in the different planes of the ***,the combined effects of inhomogeneous deformation and temperature distribution in the ND also cause the inhomogeneity of microstructure morphology and parameters in this *** analyses show that with the forming pass increasing,the aspect ratio of apincreases most in the normal-rolling plane,then in the normal-circumferential plane and least in the circumferential-rolling plane,whereas apcontent decreases in an opposite *** the ND,the aspect ratio and content of apis relatively high in the outer and inner surface areas but lowest in the central area,and these inhomogeneous characteristics can be gradually diminished with the forming pass ***,the variation of hardness inhomogeneity factor indicates that a four-pass forming with the total reduction ratio of 63%could obtain a homogenous microstructure along the ND of the TA15 alloy spun cylindrical part.

关键词： Deformation history Microstructural inhomogeneity Multi-pass flow forming TA15 alloy cylindrical parts Vickers hardness

A 16-QAM 45-Gbps 7-m Wireless link Using InP HEMT LNA and GaAs SBD Mixers at 220-GHz-Band

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China Communications 2021年第5期18卷 255-262页

作者： yukun li Yong Zhang Chengkai Wu Jianhan Cui Huali Zhu Bo Yan School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

This paper presents a 220-GHz-band 7-m wireless link with a 45-Gbps transmission data rate by using 16 quadrature amplitude modulation(16-QAM).Super-heterodyne transceiver modules are developed for transmission and reception of the modulated signals,which consist of a Schottky barrier diodes(SBD)based sub-harmonic mixer(SHM),an InP HEMT low noise amplifier(LNA),a waveguide band-pass filter(BPF),and a 108-GHz local oscillator(LO)multiplier *** transmitter features a peak transmit power of 1.41 dBm,and the IF frequency varies from 5 GHz to 20 ***,the receiver features a conversion gain of 9.3 dB in average and a noise temperature of 3052.8 *** measured results indicate that the transceiver modules enable data transmission of a 45-Gbps 16-QAM signal with Signal-Noise-Ratio(SNR)from 11.59 dB to 15.36 dB in a 7-m line-of-sight channel.

关键词： wireless link 16 quadrature amplitude modulation(16-QAM) super-heterodyne transceiver modules sub-harmonic mixer(SHM)

Residual fluoride self-activated effect enabling upgraded utilization of recycled graphite anode

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Journal of Energy Chemistry 2024年第6期93卷 24-31,I0002页

作者： Shuzhe Yang Qingqing Gao yukun li Hongwei Cai Xiaodan li Gaoxing Sun Shuxin Zhuang Yujin Tong Hao Luo Mi Lu School of Materials Science and Engineering Xiamen University of TechnologyXiamen 361024FujianChina Faculty of Physics University of Duisburg-EssenDuisburg D-47057Germany

Recycling graphite anode from spent lithium-ion batteries(SliBs)is regarded as a crucial approach to promoting sustainable energy storage ***,the recycled graphite(RG)generally presents degraded structure and ***,the residual fluoride self-activated effect is proposed for the upgraded utilization of *** and low-energy water immersion treatment not only widens the interlayer spacing,but also retains appropriate fluoride on the surface of *** analysis and experiments demonstrate that the residual fluoride can optimize li~+migration and deposition kinetics,resulting in better li~+intercalation/deintercalation in the interlayer and more stable li metal plating/stripping on the surface of RG,As a result,the designed LFP||RG full cells achieve ultrahigh reversibility(~100%Coulombic efficiency),high capacity retention(67%after 200 cycles,0.85 N/P ratio),and commendable adaptability(stable cycling without short-circuiting,0.15 N/P ratio).The energy density is improved from 334 Wh kg^(-1)of 1.1 N/P ratio to 367 Wh kg^(-1)of 0.85 N/P ratio(total mass based on cathode and anode).The exploration of RG by residual fluoride self-activated effect achieves upgraded utilization beyond fresh commercial graphite and highlights a new strategy for efficient reuse of SliBs.

关键词： Spent lithium-ion batteries Recycled graphite anode Fluoride Self-activated effect Upgraded utilization

Zika virus non-structural protein 4B interacts with DHCR7 to facilitate viral infection

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Virologica Sinica 2023年第1期38卷 23-33页

作者： Weijie Chen yukun li Xiuling Yu Zhenwei Wang Wenbiao Wang Menglan Rao Yongkui li Zhen Luo Qiwei Zhang Jinbiao liu Jianguo Wu Guangdong Provincial Key Laboratory of Virology Institute of Medical MicrobiologyJinan UniversityGuangzhou510632China Foshan Institute of Medical Microbiology Foshan528315China Halison International Peace Hospital Hebei Medical UniversityHengshui053000China Medical Research Center Guangdong Provincial People's HospitalGuangdong Academy of Medical SciencesGuangzhou510080China

Zika virus(ZIKV)evolves non-structural proteins to evade immune response and ensure efficient replication in the host *** metabolic enzyme 7-dehydrocholesterol reductase(DHCR7)was recently reported to impact innate immune responses in ZIKV ***,the vital non-structural protein and mechanisms involved in DHCR7-mediated viral evasion are not well *** this study,we demonstrated that ZIKV infection facilitated DHCR7 ***,the upregulated DHCR7 in turn facilitated ZIKV infection and blocking DHCR7 suppressed ZIKV ***,ZIKV non-structural protein 4B(NS4B)interacted with DHCR7 to induce DHCR7 ***,DHCR7 inhibited TANK-binding kinase 1(TBK1)and interferon regulatory factor 3(IRF3)phosphorylation,which resulted in the reduction of interferon-beta(IFN-β)and interferon-stimulated genes(ISGs)***,we propose that ZIKV NS4B binds to DHCR7 to repress TBK1 and IRF3 activation,which in turn inhibits IFN-βand ISGs,and thereby facilitating ZIKV *** study broadens the insights on how viral non-structural proteins antagonize innate immunity to facilitate viral infection via cholesterol metabolic enzymes and intermediates.

关键词： 7-Dehydrocholesterol reductase(DHCR7) Interferon regulatory factor 3(IRF3) Interferon-beta(IFN-β) Non-structural protein 4B(NS4B) TANK-Binding kinase 1(TBK1) Zika virus(ZIKV)

Clone-World:A visual analytic system for large scale software clones

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Visual Informatics 2019年第1期3卷 18-26页

作者： Debajyoti Mondal Manishankar Mondal Chanchal K.Roy Kevin A.Schneider yukun li Shisong Wang Department of Computer Science University of SaskatchewanSaskatoonSKCanada

With the era of big data approaching,the number of software systems,their dependencies,as well as the complexity of the individual system is becoming larger and more *** these evolving software systems is thus a primary challenge for cost-effective software management and *** this paper we perform a case study with evolving code *** programmers often need to manually analyze the co-evolution of clone fragments to decide about refactoring,tracking,and bug ***,manual analysis is time consuming,and nearly infeasible for a large number of clones,e.g.,with millions of similarity pairs,where clones are evolving over hundreds of software *** propose an interactive visual analytics system,Clone-World,which leverages big data visualization approach to manage code clones in large software ***-World,gives an intuitive yet powerful solution to the clone analytic ***-World combines multiple informationlinked zoomable views,where users can explore and analyze clones through interactive exploration in real *** studies and experts’reviews suggest that Clone-World may assist developers in many real-life software development and maintenance *** believe that Clone-World will ease the management and maintenance of clones,and inspire future innovation to adapt visual analytics to manage big software systems.

关键词： Visual analytics Software clones Multivariate networks

PGE2/EP4 skeleton interoception activity reduces vertebral endplate porosity and spinal pain with low-dose celecoxib

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Bone Research 2021年第3期9卷 396-409页

作者： Peng Xue Shenyu Wang Xiao Lyu Mei Wan Xialin li Lei Ma Neil CFord yukun li Yun Guan Wenyuan Ding Xu Cao Department of Orthopaedic Surgery The Johns Hopkins University School of MedicineBaltimoreMDUSA Department of Endocrinology The Third Hospital of Hebei Medical UniversityShijiazhuangHebeiP.R.China Key Laboratory of Orthopaedic Biomechanics of Hebei Province ShijiazhuangHebeiP.R.China Department of Spine Surgery The Third Hospital of Hebei Medical UniversityShijiazhuangHebeiP.R.China Department of Anesthesiology and Critical Care Medicine The Johns Hopkins University School of MedicineBaltimoreMDUSA

Skeletal interoception regulates bone homeostasis through the prostaglandin E2(PGE2)concentration in *** endplates undergo ossification and become highly porous during intervertebral disc degeneration and *** found that the PGE2 concentration was elevated in porous endplates to generate spinal ***,treatment with a high-dose cyclooxygenase 2 inhibitor(celecoxib,80 mg·kg−1 per day)decreased the prostaglandin E2 concentration and attenuated spinal pain in mice with lumbar spine ***,this treatment impaired bone formation in porous endplates,and spinal pain recurred after discontinuing the ***,low-dose celecoxib(20 mg·kg−1 per day,which is equivalent to one-quarter of the clinical maximum dosage)induced a latent inhibition of spinal pain at 3 weeks post-treatment,which persisted even after discontinuing ***,when the prostaglandin E2 concentration was maintained at the physiological level with low-dose celecoxib,endplate porosity was reduced significantly,which was associated with decreased sensory nerve innervation and spinal *** findings suggest that low-dose celecoxib may help to maintain skeletal interoception and decrease vertebral endplate porosity,thereby reducing sensory innervation and spinal pain in mice.

关键词： pain dosage impaired

A terahertz on-chip InP-based power combiner designed using coupled-grounded coplanar waveguide lines

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Chinese Physics B 2021年第12期30卷 329-333页

作者： Huali Zhu Yong Zhang Kun Qu Haomiao Wei yukun li Yuehang Xu Ruimin Xu School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

This article presents the design and performance of a terahertz on-chip coupled-grounded coplanar waveguide(GCPW)power combiner using a 50μm-thick InP *** proposed topology uses two coupled-GCPW lines at the end of the input port to substitute two quarter-wavelength GCPW lines,which is different from the conventional Wilkinson power combiner and can availably minimize the coverage *** to the results obtained,for the frequency range of 210-250 GHz,the insertion losses for each two-way combiner and four-way combiner were lower than 1.05 dB and1.35 dB,respectively,and the in-band return losses were better than 11 ***,the proposed on-chip GCPW-based combiners achieved a compromise in low-loss,broadband,and small-size,which can find wide applications in terahertz bands,such as power amplifiers and signal distribution networks.

关键词： coupled-GCPW InP technology terahertz monolithic integrated circuits(TMICs) Wilkinson power combiner