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Applied Mathematics(A Journal of Chinese Universities) 2014年第2期29卷 171-182页

作者： LIU Qun teng fei LUO Zhen-dong School of Mathematics and Computer Science Guizhou Normal University School of Mathematics Sciences Kaili college School of Mathematics and Physics North China Electric Power University

A reduced-order extrapolation algorithm based on Crank-Nicolson least-squares mixed finite element （CNLSMFE） formulation and proper orthogonal decomposition （POD） technique for two-dimensional （2D） Sobolev equations is established. The error estimates of the reduced-order CNLSMFE solutions and the implementation for the reduced-order extrapolation algorithm are provided. A numerical example is used to show that the results of numerical computations are consistent with theoretical conclusions. Moreover, it is shown that the reduced-order extrapolation algorithm is feasible and efficient for seeking numerical solutions to 2D Sobolev equations.

关键词： Reduced-order extrapolation aigorithm Crank-Nicolson least*squares mixed finite element for-mulation proper orthogonal decomposition technique Sobolev equations.

Accuracy assessment of global vertical displacement loading tide models for the equatorial and Indian Ocean

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Acta Oceanologica Sinica 2024年第9期43卷 11-25页

作者： Xiaoqing Xu Haidong Pan fei teng Zexun Wei First Institute of Oceanography and Key Laboratory of Marine Science and Numerical ModelingMinistry of Natural ResourcesQingdao 266061China Laboratory for Regional Oceanography and Numerical Modeling Qingdao Marine Science and Technology CenterQingdao 266237China Shandong Key Laboratory of Marine Science and Numerical Modeling Qingdao 266061China

The three-dimensional displacements caused by ocean loading effects are significant enough to impact spatial geodetic measurements on sub-daily or longer timescales,particularly in the vertical ***,most tide models incorporate the distribution of vertical displacement loading tides;however,their accuracy has not been assessed for the equatorial and Indian Ocean *** Positioning System(GPS)observations provide high-precision data on sea-level changes,enabling the assessment of the accuracy and reliability of vertical displacement tide ***,because the tidal period of the K_(2) constituent is almost identical to the orbital period of GPS constellations,the estimation of the K_(2) tidal constituent from GPS observations is not *** this study,the principle of smoothness is employed to correct the systematic error in K_(2) estimates in GPS observations through quadratic *** the adjusted harmonic constants from 31 GPS stations for the equatorial and Indian Ocean,the accuracy of eight major constituents from five global vertical displacement tide models(FES2014,EOT11a,GOT4.10c,GOT4.8,and NAO.99b)is evaluated for the equatorial and Indian *** results indicate that the EOT11a and FES2014 models exhibit higher accuracy in the vertical displacement tide models for the equatorial and Indian Ocean,with root sum squares errors of 2.29 mm and 2.34 mm,***,a brief analysis of the vertical displacement tide distribution characteristics of the eight major constituents for the equatorial and Indian Ocean was conducted using the EOT11a model.

关键词： accuracy assessment vertical displacement loading tide models tidal admittance equatorial and Indian Ocean GPS constellation

Effect of process parameters on the microstructure and properties of laser-clad FeNiCoCrTi0.5 high-entropy alloy coating

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International Journal of Minerals,Metallurgy and Materials 2020年第5期27卷 630-639页

作者： Ying Zhang teng-fei Han Meng Xiao Yi-fu Shen College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics(NUAA)Nanjing 210016China Nanjing Institute of Advanced Laser Technology Nanjing 210038China

FeNiCoCrTi0.5 coatings with different process parameters were fabricated by laser cladding. The macro-morphology, phase, microstructure, hardness, and wear resistance of each coating were studied. The smoothness and dilution rate of the FeNiCoCrTi0.5 coating generally increased with the increase of specific energy(Es), which is the laser irradiation energy received by a unit area. FeNiCoCrTi0.5 coatings at different parameters had bcc, fcc, and Ti-rich phases as well as equiaxed, dendritic, and columnar structures. When Es increased, the size of each structure increased and the distribution area of the columnar and dendritic structures changed. The prepared FeNiCoCrTi0.5 coating with the Es of 72.22 J·mm-2 had the highest hardness and the best wear resistance, the highest hardness of the coating reached HV 498.37, which is twice the substrate hardness. The average hardness of the FeNiCoCrTi0.5 coating with the Es of 72.22 J·mm-2 was 15.8% higher than the lowest average hardness of the coating with the Es of 108.33 J·mm-2. The worn surface morphologies indicate that the FeNiCoCrTi0.5 coatings exhibited abrasive wear.

关键词： high-entropy alloy coating 45 steel laser cladding microstructure wear resistance

Sparse-view neutron CT 3D image reconstruction algorithm based on split Bregman method

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Nuclear Science and Techniques 2024年第9期35卷 41-55页

作者： teng-fei Zhu Yang Liu Zhi Luo Xiao-Ping Ouyang School of Nuclear Science and Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Xi’an 710024China

As a complement to X-ray computed tomography(CT),neutron tomography has been extensively used in nuclear engineer-ing,materials science,cultural heritage,and industrial *** of the attenuation matrix for neutron tomography with a traditional analytical algorithm requires hundreds of projection views in the range of 0°to 180°and typically takes several hours to *** a low time-resolved resolution degrades the quality of neutron *** the number of projection acquisitions is an important approach to improve the time resolution of images;however,this requires efficient reconstruction ***,sparse-view reconstruction algorithms in neutron tomography need to be *** this study,we investigated the three-dimensional reconstruction algorithm for sparse-view neu-tron CT *** enhance the reconstructed image quality of neutron CT,we propose an algorithm that uses OS-SART to reconstruct images and a split Bregman to solve for the total variation(SBTV).A comparative analysis of the performances of each reconstruction algorithm was performed using simulated and actual experimental *** to the analyzed results,OS-SART-SBTV is superior to the other algorithms in terms of denoising,suppressing artifacts,and preserving detailed structural information of images.

关键词： Neutron CT OS-SART Sparse-view 3D reconstruction Split Bregman Total variation

3D robust anisotropic diffusion filtering algorithm for sparse view neutron computed tomography 3D image reconstruction

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Nuclear Science and Techniques 2024年第3期35卷 13-29页

作者： Yang Liu teng-fei Zhu Zhi Luo Xiao-Ping Ouyang School of Nuclear Science and Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Xi’an 710024China

The most critical part of a neutron computed tomography(NCT) system is the image processing algorithm,which directly affects the quality and speed of the reconstructed *** types of noise in the system can degrade the quality of the reconstructed ***,to improve the quality of the reconstructed images of NCT systems,efficient image processing algorithms must be *** anisotropic diffusion filtering(ADF) algorithm can not only effectively suppress the noise in the projection data,but also preserve the image edge structure information by reducing the diffusion at the image ***,we propose the application of the ADF algorithm for NCT image *** compare the performance of different algorithms in NCT systems,we reconstructed images using the ordered subset simultaneous algebraic reconstruction technique(OS-SART) algorithm with different regular terms as image processing *** the iterative reconstruction,we selected two image processing algorithms,the Total Variation and split Bregman solved total variation algorithms,for comparison with the performance of the ADF ***,the filtered back-projection algorithm was used for comparison with an iterative *** reconstructing the projection data of the numerical and clock models,we compared and analyzed the effects of each algorithm applied in the NCT *** on the reconstruction results,OS-SART-ADF outperformed the other algorithms in terms of denoising,preserving the edge structure,and suppressing *** example,when the 3D Shepp–Logan was reconstructed at 25 views,the root mean square error of OS-SART-ADF was the smallest among the four iterative algorithms,at only *** universal quality index,mean structural similarity,and correlation coefficient of the reconstructed image were the largest among all algorithms,with values of 0.9877,0.9878,and 0.9887,respectively.

关键词： NCT OS-SART Sparse-view Anisotropic diffusion filtering

First-order primal-dual algorithm for sparse-view neutron computed tomography-based three-dimensional image reconstruction

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Nuclear Science and Techniques 2023年第8期34卷 35-53页

Neutron computed tomography(NCT)is widely used as a noninvasive measurement technique in nuclear engineering,thermal hydraulics,and cultural *** neutron source intensity of NCT is usually low and the scan time is long,resulting in a projection image containing severe *** reduce the scanning time and increase the image reconstruction quality,an effective reconstruction algorithm must be *** CT image reconstruction,the reconstruction algorithms can be divided into three categories:analytical algorithms,iterative algorithms,and deep *** the analytical algorithm requires complete projection data,it is not suitable for reconstruction in harsh environments,such as strong radia-tion,high temperature,and high *** learning requires large amounts of data and complex models,which cannot be easily deployed,as well as has a high computational complexity and poor ***,this paper proposes the OS-SART-PDTV iterative algorithm,which uses the ordered subset simultaneous algebraic reconstruction technique(OS-SART)algorithm to reconstruct the image and the first-order primal–dual algorithm to solve the total variation(PDTV),for sparse-view NCT three-dimensional *** novel algorithm was compared with other algorithms(FBP,OS-SART-TV,OS-SART-AwTV,and OS-SART-FGPTV)by simulating the experimental data and actual neutron projection *** reconstruction results demonstrate that the proposed algorithm outperforms the FBP,OS-SART-TV,OS-SART-AwTV,and OS-SART-FGPTV algorithms in terms of preserving edge structure,denoising,and suppressing artifacts.

关键词： NCT First-order primal-dual algorithm OS-SART Total variation Sparse-view

Emission Enhancement of Fluorescent Molecules by Antireflective Arrays

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Research 2019年第1期2019卷 115-122页

作者： Hongbo Xu Lingxiao Liu fei teng Nan Lu MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of Technology150001 HarbinChina State Key Laboratory of Supramolecular Structure and Materials College ChemistryJilin University130012 ChangchunChina

Traditional fluorescence enhancement based on a match of the maximum excitation or emission of fluorescence molecule with the spectra of the nanostructure can hardly enhance blue and red fluorescent ***,an enhanced method which is a new strategy based on the antireflective array has been developed to enhance the emission of blue and red fluorescent *** fluorescence emission is enhanced by increasing the absorption at excitation wavelengths of the fluorescent molecules and reducing the fluorescent energy dissipation with an antireflective *** introducing the antireflective arrays,the emission enhancement of blue and red fluorescent molecules is,respectively,up to 14 and 18 *** is a universal and effective strategy for enhancing fluorescence emission,which could be applied to enhance the intensity of organic LED and imaging.

关键词： excitation introducing Fluorescent

Estimating peak response frequencies in a tidal band in the seas adjacent to China with a numerical model

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Acta Oceanologica Sinica 2015年第1期34卷 29-37页

作者： CUI Xinmei FANG Guohong teng fei WU Di State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of Sciences University of Chinese Academy of Sciences First Institute of Oceanography State Oceanic Administration Ocean University of China

A numerical method is designed to examine the response properties of real sea areas to open ocean forcing. The application of this method to modeling the China＇s adjacent seas shows that the Bohai Sea has a highest peak response frequency （PRF） of 1.52 d^-1; the northern Yellow Sea has a PRF of 1.69 d^-1; the Gyeonggi Bay has a high amplitude gain plateau in the frequency band roughly from 1.7 to 2.7 d^-1; the Yellow Sea （includ- ing the Gyeonggi Bay）, the East China Sea shelf and the Taiwan Strait have a common high amplitude gain band with frequencies around 1.76 to 1.78 d^-1 and are shown to be a system that responds to the open ocean forcing in favor of amplifying the waves with frequencies in this band; the Beibu Gulf, the Gulf of Thailand and the South China Sea deep basin have PRFs of 0.91, 1.01 and 0.98 d^-1 respectively. In addition, the East China Sea has a Poincare mode PRF of 3.91 d^-1. The PRFs of the Bohal Sea, the northern Yellow Sea, the Bei- bu Gulf and the South China Sea can be explained by a classical quarter （half for the Bohai Sea） wavelength resonance theory. The results show that further investigations are needed for the response dynamics of the Yellow Sea-East China Sea-Taiwan Strait system, the East China Sea Poincare mode, the Talwan Strait, and the Gulf of Thailand.

关键词： China's adjacent seas response to tidal forcing peak response frequency resonance numericalmodel

A Stabilized Crank-Nicolson Mixed Finite Element Method for Non-stationary Parabolized Navier-Stokes Equations

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Acta Mathematicae Applicatae Sinica 2017年第2期33卷 409-416页

作者： Yan-jie ZHOU fei teng Zhen-dong LUO School of Science Beijing Technology and Business University Beijing 100048 China School of Mathematics and Physics North China Electric Power University Beijing 102206 China

In this study, a time semi-discrete Crank-Nicolson （CN） formulation with second-order time accu- racy for the non-stationary parabolized Navier-Stokes equations is firstly established. And then, a fully discrete stabilized CN mixed finite element （SCNMFE） formulation based on two local Gauss integrals and parameter- free with the second-order time accuracy is established directly from the time semi-discrete CN formulation. Thus, it could avoid the discussion for semi-discrete SCNMFE formulation with respect to spatial variables and its theoretical analysis becomes very simple. Finaly, the error estimates of SCNMFE solutions are provided.

关键词： parabolized Navier-Stokes equations stabilized Crank-Nicolson mixed finite element formulation error estimate

Performance of a single-stage auto-cascade refrigerator operating with a rectifying column at the temperature level of -60°C

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第2期12卷 139-145页

作者： Qin WANG Kang CUI teng-fei SUN Guang-ming CHEN Institute of Refrigeration and Cryogenics State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China

This paper proposes a new approach to the performance optimization of an auto-cascade refrigerator(ACR) operating with a rectifying column and six types of binary refrigerants(R23/R134a,R23/R227ea,R23/R236fa,R170/R290,R170/R600a,and R170/R600) at a temperature level of -60 °C. Half of the six binary refrigerants are nonflammable,of which the 0.5 and the 0.6 mole fractions of R23 for the R23/R236fa possess the most prospective composition for the medium and low suction pressure compressors,respectively. The remaining three binary refrigerants are flammable but with low global warming potentials,of which the 0.6 mole fraction of R170 for the R170/R600 is the most prospective one. The results show that the overall matching as well as local matching of heat capacity rates of hot and cold refrigerants in the recuperators are important for the improvement of coefficient of performance of the cycle,which can be adjusted through the simultaneous optimization of the pressure level and composition. The new approach proposed also offers a wider range of applications to the optimization in performance of the cycle using multi-component refrigerants.

关键词： Auto-cascade Binary refrigerant Refrigerator Optimization