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A Non-Intrusive Reduced Basis EKI for Time Fractional Diffusion Inverse Problems

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Acta Mathematicae Applicatae Sinica 2020年第1期36卷 183-202页

作者： Feng-lian yang liang YAN College of Science Hohai UniversityNanjing 210098China School of Mathematics Southeast UniversityNanjing210096China

In this study,we consider an ensemble Kalman inversion(EKI)for the numerical solution of time fractional diffusion inverse problems(TFDIPs).Computational challenges in the EKI arise from the need for repeated evaluations of the forward *** address this challenge by introducing a non-intrusive reduced basis(RB)method for constructing surrogate models to reduce computational *** this method,a reduced basis is extracted from a set of full-order snapshots by the proper orthogonal decomposition(POD),and a doubly stochastic radial basis function(DSRBF)is used to learn the projection *** DSRBF is carried out in the offline stage with a stochastic leave-one-out cross-validation algorithm to select the shape parameter,and the outputs for new parameter values can be obtained rapidly during the online *** to the complete decoupling of the offline and online stages,the proposed non-intrusive RB method–referred to as POD-DSRBF–provides a powerful tool to accelerate the EKI approach for *** demonstrate the practical performance of the proposed strategies through two nonlinear time-fractional diffusion inverse *** numerical results indicate that the new algorithm can achieve significant computational gains without sacrificing accuracy.

关键词： fractional differential equations ensemble Kalman inversion surrogate modeling reduced basis method

Processing and mechanical properties of 2024 aluminum matrix composites containing Tungsten and Tantalum prepared by PM

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Rare Metals 2006年第z2期25卷 136-140页

作者： lian Youyun yang Zhimin yang Jian MAO Changhui Advanced Electronic Materials Institute General Research Institute for Non-Ferrous Metals Beijing 100088 China Advanced Electronic Materials Institute General Research Institute for Non-Ferrous Metals Beijing 100088 China Advanced Electronic Materials Institute General Research Institute for Non-Ferrous Metals Beijing 100088 China Advanced Electronic Materials Institute General Research Institute for Non-Ferrous Metals Beijing 100088 China

The 2024 Al composites containing W, Ta were fabricated by powder metallurgy for their potential use as shielding material. W, Ta powders and gas-atomized 2024 Al aluminum powders were mixed by a ball mixer. The mixtures were consolidated by cold isostatic pressing (CIP) and then hot-extruded into full-density bars. The extruded bars were heat treated in T6 conditions. The microstructure and its relationship with the mechanical properties were investigated by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the particles of nonuniform size and irregular shape randomly disperse in the 2024 aluminum alloy matrix. The tensile tests show that an increase of tensile strength and decrease of elongation to failure of the heat treated composites compared with the extruded composites.

关键词： 2024 Al matrix composites powder metallurgy hot extrusion heat treatment

Time-Domain Nonlinear Wave-Current Interaction with A Steep Wave Riser Considering Internal Flow Effect

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China Ocean Engineering 2021年第3期35卷 410-421页

作者： TANG lian-yang CHENG Yong JI Chun-yan School of naval architecture and ocean engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Nippon Kaiji Kyokai(China)Co. LtdShanghai 200336China

The nonlinear dynamic response induced by the wave-current interaction on a deepwater steep wave riser(SWR)is numerically investigated based on a three-dimensional(3 D)time-domain finite element method(FEM).The governing equation considering internal flow is established in the global coordinate *** whole SWR consists of three segments:the decline segment,buoyancy segment and hang-off segment,in which the buoyancy segment is wrapped by several buoyancy modules in the middle section,leading to the arch bend and sag bend.A Newmark-β iterative scheme is adopted for the accurate analysis to solve the governing equation and update the dynamic response at each time *** proposed method is verified through the published results for the dynamic response of steel catenary riser(SCR)and static configuration of steel lazy wave riser(SLWR).Simulations are executed to study the influence of wave height,current velocity/direction,internal flow density/velocity and top-end pressure on the tension,configuration and bending moment of the *** results indicate that the influence of the current on the configuration and mechanical behavior of the SWR is greater than that of the wave,especially in the middle *** increasing current velocity,the suspending height of the middle section drops,meanwhile,its bending moment decreases accordingly,but the tension increases *** a fixed external load,the increasing internal flow density induces the amplification of the tension at the hang-off segment and the mitigation at the decline segment,while the opposite trend occurs at the bending moment.

关键词： steep wave riser(SWR) nonlinear dynamic response wave-current interaction time-domain finite element method(FEM)

Nonlinear Analysis of Bidirectional Vortex-Induced Vibration of A Deepwater Steep Wave Riser Subjected to Oblique Currents

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China Ocean Engineering 2021年第6期35卷 852-865页

作者： CHENG Yong TANG lian-yang JI Chun-yan School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Nippon Kaiji Kyokai(China)Co. LtdShanghai 200336China

An improved three-dimensional(3D)time-domain couple model is established in this paper to simulate the bidirectional vortex-induced vibration(VIV)of a deepwater steep wave riser(SWR)subjected to oblique *** this model,the nonlinear motion equations of the riser are established in the global coordinate system based on the slender rod theory with the finite element *** der Pol equations are used to describe the lift forces induced by the x-and y-direction current components,*** coupled equations at each time step are solved by a Newmark-βiterative scheme for the SWR *** present model is verified by comparison with the published experimental results for a top-tension ***,a series of simulations are executed to determine the influences of the oblique angle/velocity of the current,different top-end positions and the length of the buoyancy segment on the VIV displacement,oscillating frequency as well as hydrodynamic coefficients of the *** results demonstrate that there exists a coupled resonant VIV corresponding to x-direction and y-direction,***,the effective frequency is almost identical between the vibrations at the hang-off segment along x and y *** addition of the buoyancy modules in the middle of the SWR has a beneficial impact on the lift force of three segments and simultaneously limits the VIV response,especially at the decline segment and the hang-off ***,the incident current direction significantly affects the motion trajectory of the SWR which mainly includes the fusiform and rectangle shapes.

关键词： steep wave riser(SWR) bidirectional vortex-induced vibration wake oscillator model time-domain finite element method(TDFEM)

Impacts of advanced treatment processes on elimination of antibiotic resistance genes in a municipal waste water treatment plant

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Frontiers of Environmental Science & Engineering 2019年第3期13卷 69-78页

作者： lian yang Qinxue Wen Zhiqiang Chen Ran Duan Pan yang State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology (SKLUWRE HIT) Harbin 150090 China National & Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology Suzhou University of Science and Technology Suzhou 215009 China

Antibiotic resistance genes (ARGs) pose a serious threat to public health. Wastewater treatment plants (WWTPs) are essential for controlling the release of ARGs into the environment. This study investigated ARG distribution at every step in the treatment process of a municipal WWTP located in Harbin for six consecutive months. Changes in ARG distribution involved in two advanced secondary effluent treatment processes, ozonation and granular activated carbon (GAC) adsorption, were analyzed. Biological treatment resulted in the highest ARG removal (0.76-1.94 log reduction), followed by ultraviolet (UV) disinfection (less than 0.5-log reduction). Primary treatment could not significantly remove ARGs. ARG removal efficiency increased with an increase in the ozone dose below 40 mg/L. However, amorphous GAC (AGAC) adsorption with a hydraulic retention time (HRT) of 1 h showed better removal of ARGs, total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) than ozonation at a 60 mg/L dose. UV treatment could efficiently reduce the relative ARG abundance, despite presenting the lowest efficiency for the reduction of absolute ARG abundance compared with GAC and ozone treatments. The combination of ozone and AGAC can significantly improve the removal of ARGs, TOC, TN and TP. These results indicate that a treatment including biological processing, ozonation, and AGAC adsorption is a promising strategy for removing ARGs and refractory organic substances from sewage.

关键词： Antibiotic resistance genes (ARGs) Wastewater treatment plant (WWTP) Ultraviolet (UV) Ozonation Granular activated carbon (GAC)

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Acta Mathematica Sinica,English Series 2007年第8期23卷 1405-1412页

作者： lian Zhong yang Hong Xun YI School of Mathematics & Systems Science Shandong University Ji'nan 250100 P. R. China

In this paper, we prove several results concerning meromorphic functions f and g of hyperorder less than one such that f^（j） and g^（j） have the same zeros and poles for j=0, 1, 2. We provide some examples to show ... 详细信息

关键词： meromorphic functions uniqueness sharing values

Quantifying coherence with dynamical discord

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Chinese Physics B 2021年第12期30卷 222-228页

作者： lian-Wu yang Yun-Jie Xia School of Physical Science and Intelligent Engineering Jining UniversityQufu 273155China Shandong Provincial Key Laboratory of Laser Polarization and Information Technology Department of PhysicsQufu Normal UniversityQufu 273165China

Quantum coherence and discord are two kinds of manifestations of *** calculating the coherence and discord in the specific bipartite quantum systems,we show quantitative connections between the coherence and the discord in the bipartite quantum systems created from local systems with the help of incoherent *** show that the coherence bounds the dynamical discord,and under particular conditions of the initial quantum states,the coherence of single systems is equal to the dynamical *** extend these results to the multipartite quantum systems.

关键词： quantum coherence dynamical discord relative entropy

Insecticidal activities of garlic substances against adults of grain moth, Sitotroga cerealella （Lepidoptera： Gelechiidae）

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Insect Science 2012年第2期19卷 205-212页

作者： Feng-lian yang Fen Zhu Chao-liang Lei Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory Huazhong Agricultural UniversityWuhanChina

The angoumois grain moth, Sitotroga cerealella （Olivier）, is one of the most serious stored grain pests around the world. In attempts to reduce the losses caused by the moth and to suppress its populations, the fumigant activities, behavioral influence and ovipositional inhibition of garlic （Allium sativum） essential oil and its two major components, diallyl disulfide and diallyl trisulfide, were investigated against the adult grain moth. Their effects on reduction in survival of first instar larvae to adult emergence were also evaluated. Results showed that these three materials （garlic essential oil, diallyl disulfide and diallyl trisulfide） had significant fumigant activity with 50% lethal concentration values at 1.33, 0.99, and 1.02/zL/L air space, respectively; meanwhile, the three materials possessed high behavioral deterrent activities against adults in the Y-tube olfactometer. When applied to rice grains, these materials reduced adult longevity and inhibited oviposition, with ovipositional inhibition above 70% at a concentration of 1.5uL/25 g in either no-choice or two-choice tests. In short, the study showed that both diallyl disulfide and diallyl trisulfide, like garlic essential oil, acted as fitrnigants, produced behavioral deter- rence and inhibited oviposition against angoumois grain moth. Our work here indicates that diallyl disulfide and diallyl trisulfide may serve as potential alternatives for grain protectants since both of them can be prepared easily from readily available chemicals.

关键词： behavioral deterrence essential oil fumigant garlic oviposition inhibition,Sitotroga cerealella

Dynamics analysis in a tumor-immune system with chemotherapy

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Chinese Physics B 2021年第5期30卷 673-681页

作者： Hai-Ying Liu Hong-Li yang lian-Gui yang School of Mathematical Sciences Inner Mongolia UniversityHohhot 010021China

An ordinary differential equation(ODE)model of tumor growth with the effect of tumor-immune interaction and chemotherapeutic drug is presented and *** analyzing the existence and stability of equilibrium points,the dynamic behavior of the system is discussed *** chaotic dynamics can be obtained in our model by equilibria analysis,which show the existence of chaos by calculating the Lyapunov exponents and the Lyapunov dimension of the ***,the action of the infusion rate of the chemotherapeutic drug on the resulting dynamics is investigated,which suggests that the application of chemotherapeutic drug can effectively control tumor ***,in the case of high-dose chemotherapeutic drug,chemotherapy-induced effector immune cells damage seriously,which may cause treatment failure.

关键词： dynamical model tumor-immune system chemotherapy chaos