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

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

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Strong Electromagnetic pulse Interference Loading Method on Electrical Equipment under Operation state

Strong Electromagnetic Pulse Interference Loading Method on ...

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2024 Photonics and Electromagnetics Research Symposium, PIERS 2024

作者： Qin, Feng Cui, Zhitong Chen, Wei Nie, Xin Wu, Wei Wang, Yixiong Northwest Institute of Nuclear Technology State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Xi'an710049 China

ISBN: (纸本)9798350375909

Power equipment displays notable variations in port characteristics, resulting in pronounced waveform distortion during High-altitude Electromagnetic pulse (HEMP) effect tests, along with low coupling efficiency. Moreover, the equipment operates at elevated voltages, posing a risk of test system failures during powered testing. Presently, there are no established methodologies or testing platforms for conducting HEMP effect tests on power equipment, either domestically or internationally. This paper comprehensively explores the physical interaction processes between the power system and the HEMP current injection test system. It introduces a pulse interference loading method based on the concept of equivalent "zero potential,"which effectively addresses the challenge of the pulse source's internal circuit insulation not being able to withstand high-frequency voltages and power capacity. Moreover, it enables the precise phase loading of nanosecond pulses onto millisecond-level power frequency signals, as well as efficient coupling between the pulse source output and power equipment. This method facilitates the acquisition of phenomena and threshold data related to the electromagnetic pulse effects on power equipment under real-world operating conditions. © 2024 IEEE.

关键词： Hemp

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Efficient Absorbing Boundary for LADI-FDTD Method

Efficient Absorbing Boundary for LADI-FDTD Method

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2023 International Applied Computational Electromagnetics Society Symposium, ACES-China 2023

作者： Wenbing, Wang Mo, Zhao Xutong, Wang Yifei, Liu Jinghai, Guo Northwest Institute of Nuclear Technology State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Xi'an China

ISBN: (纸本)9781733509657

The finite difference time domain (FDTD) method is one of the most universal numerical methods for calculating electromagnetic problem. The conventional FDTD method was limited by the stability condition named CFL (Courant, Friedrichs and Lewy), and the calculation efficiency to be low. However, a method called leapfrog alternating direction implicit finite difference time domain (LADI-FDTD) was proposed, it was proved to be unconditional stability and have high computational efficiency. Moreover, the setting of absorbing boundary conditions plays an important role in FDTD. A new absorbing boundary based on Huygens surface combined with other boundary is applied to LADI-FDTD method, and its iterative equations were derived, it's obviously that is simple and easy to realize. Finally, the excellent absorbing performance of the boundary based on Huygens surface was verified by numerical calculation, which can significantly improve the efficiency of the method. © 2023 Applied Computational Electromagnetics Society (ACES).

关键词： Finite difference time domain method

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A High Precision Parameter Estimation Method of Double Exponential pulse Based on Artificial Neural Network

A High Precision Parameter Estimation Method of Double Expon...

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2023 Photonics and Electromagnetics Research Symposium, PIERS 2023

作者： Zhu, Zhizhen Yang, Jing Shi, Yuewu Liu, Zheng Nie, Xin Northwest Institute of Nuclear Technology State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Xi'an China

ISBN: (纸本)9798350312843

Double exponential pulse is the waveform of high-power electromagnetic environments. 10-90% rise time tr and pulse width at half maximum tw are the important parameters of the waveform. They can be determined by α and β which are the key parameters of double exponential function. The transformation from tr, tw to α, β is frequently used and very necessary in EM simulation and data analysis. In this paper, based on artificial neural network we create a new training data set and establish a simple architecture. α, β can be given out directly from the model. Compared to piecewise linear fitting and look-up table method, the method proposed in this paper has the advantages of both high precision and small amount of pre-processing data. The maximum estimation error of both α and β is less than 0.1%. © 2023 IEEE.

关键词： Neural networks

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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

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

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

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Observation and simulation of n=1 Reversed Shear Alfvén Eigenmode on the HL-2A Tokamak

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Chinese Physics Letters 2022年第10期39卷 26-33页

作者： P.W.Shi Y.R.Yang W.Chen Z.B.Shi Z.C.Yang L.M.Yu T.B.Wang X.X.He X.Q.Ji W.L.Zhong M.Xu X.R.Duan Southwestern Institute of Physics Chengdu 610041China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi’an 710024China

A branch of high-frequency Alfvenic modes is observed on the HL-2A *** electromagnetic mode can be driven unstably in the plasma with an off-axis neutral beam *** mode frequency keeps almost unchanged or presents a slow-sweeping behavior,depending on the detail current *** poloidal and toroidal mode numbers are𝑚m/n=1/*** mode has a quite short duration(≤20 ms)and usually appears 5-10 ms after the neutral beam being injected into the *** simulations based on M3D-K have also been carried *** result suggests that co-passing energetic particles are responsible for the mode *** simulated mode structures are localized nearby location of minimum safety factor(q_(min))and agree with the structures obtained through tomography of soft x-ray ***,the modes are localized in the continuum gap and their frequencies increase with variation of𝑞min in a wide *** but not least,the characteristic of unchanged frequency on experiment is also reproduced by the nonlinear simulation with a fixed safety *** those evidences indicate that the𝑛n=1 high-frequency mode may belong to a reversed shear Alfven eigenmode.

关键词： Alfven mode unchanged

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Charge collection narrowing mechanism in electronic-grade-diamond photodetectors

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Opto-Electronic Advances 2024年第6期7卷 1-3页

作者： Xiaoping Ouyang State Key Laboratory of Intense Pulsed Radiation Simulation and Effect and Radiation Detection Research Center Northwest Institute of Nuclear TechnologyXi’an 710024China

Recently,an extreme narrowband spectral response of only 8 nm in electronic-grade diamond-based photodetectors has been observed by Zheng Wei and his colleagues from Sun Yat-sen University for the first time.A charge collection narrowing mechanism assisted by free exciton radiative recombination is proposed,which well reveals the characteristic spectral response of diamond.

关键词： mechanism electronic extreme

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The design of the x-ray radiography with a rear illuminated backlighter for a nanosecond laser with dozens of joules 7

The design of the x-ray radiography with a rear illuminated ...

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7th International Symposium on Laser Interaction with Matter, LIMIS 2024

作者： Wang, Peng Liu, Yanpeng Wang, Hao Xue, Quanxi Wang, Yousheng Huang, Chao Li, GaoPeng Yan, Wenbo Yi, Aiping Ye, JingFeng Huang, Ke State Key Laboratory of Laser Interaction with Matter Xi'an710024 China National Key Laboratory of Intense Pulsed Radiation Simulation and Effect Xi'an710024 China Northwest Institute of Nuclear Technology Xi'an710024 China

ISBN: (数字)9781510688865

ISBN: (纸本)9781510688858

High-power laser facility is becoming an important experimental platform for the study of micro-ejection phenomenon, and X-ray radiography is an important diagnostic technique in this experiment. Compared to the X-ray radiography driven by picosecond or femtosecond laser, the X-ray radiography driven by nanosecond laser can capture multiple images of different time in a single experiment, which is helpful for the evolution diagnosis in high energy density physics. However, this is difficult for a nanosecond laser with only a few dozen of joules of energy, requiring very sophisticated design. This paper introduces the design of high spatial resolution X-ray radiography based on a nanosecond laser with dozens of joules. Firstly, the numerical simulation work is introduced, including the analysis of laser driven micro-ejection experiments and the X-ray backlight characteristic of different types of backlighting target by using the radiation hydrodynamics code. Secondly, the design of the experimental target based on the physical analysis and the target chamber structure is presented. Copyright © 2024 SPIE.

关键词： X ray radiography

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Realizing large strain at low electric field in Pb(Zr,Ti)O_(3)-based piezoelectric ceramics via engineering lattice distortion and domain structure

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Journal of Advanced Ceramics 2024年第9期13卷 1409-1421页

作者： Denghui Jiang Feng Luo Kao Pei Hongyu Yang Linzhuang Xing Yangxi Yan Mo Zhao Zhimin Li Yue Hao School of Advanced Materials and Nanotechnology Xidian UniversityXi’an 710126China Academy of Advanced Interdisciplinary Research Xidian UniversityXi’an 710071China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect(Northwest Institute of Nuclear Technology) Xi’an 710024China National Key Laboratory of Wide Bandgap Semiconductor Devices and Integrated Technology Xidian UniversityXi’an 710071China

Pb(Zr,Ti)O_(3)-based ceramics are the mainstream materials for commercial multilayer piezoelectric ceramic actuators,but to date,large strains at low electric fields have not been well ***,0.95Pb(Zr_(0.56)Ti_(0.44))O_(3)–0.05(Bi_(0.5)Na_(0.5))TiO_(3–x)BaZrO_(3)(PZT–BNT–xBZ)ceramics with efficient ferroelectric domain wall motion were designed and realized by reducing lattice distortion and changing the domain *** is found that the introduction of BaZrO_(3)(BZ)weakens the tetragonal phase distortion of PZT,contributing to a reduction in the mechanical stress that impedes the migration of domain ***,the domain structures could be modified by adjusting the BZ content,where short and broad striped domains are constructed with high amplitude characteristics to enhance the domain wall motion.A large strain of 0.39%is accordingly achieved at an electric field as low as 40 kV/cm for the sample with x=0.03,accompanied by excellent temperature stability over the temperature range of 30–210℃.This study delves into the synergistic effects of reducing lattice distortion and changing domain structure on domain wall motion and provides an effective strategy to improve the strain of PZT-based piezoelectric ceramics.

关键词： PZT ceramic strain ferroelectric domain lattice distortion

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Application progress and prospect of 100-joule high-power XeCl excimer laser 7

Application progress and prospect of 100-joule high-power Xe...

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7th International Symposium on Laser Interaction with Matter, LIMIS 2024

作者： Xue, Quanxi Liu, Yanpeng Wang, Hao Wang, Peng Yi, Aiping Zhao, Xueqing Huang, Chao Wang, Yousheng Yan, Wenbo Li, Gaopeng Wang, Dahui Huang, Ke Liu, Jingru National Key Laboratory of Intense Pulsed Radiation Simulation and Effect Shaanxi Xi'an China State Key Laboratory of Laser Interaction with Matter Shaanxi Xi'an China Northwest Institute of Nuclear Technology Shaanxi Xi'an China

ISBN: (数字)9781510688865

ISBN: (纸本)9781510688858

High power excimer laser has the characteristics of good irradiation uniformity on target surface, repeatable operation and high electro-optical efficiency. It has played an important role in the research fields of inertial confinement fusion, high energy density physics, plasma physics, and so on. In this paper, the high power XeCl excimer laser device in Northwest Institute of Nuclear Technology is briefly introduced. Secondly, the application progress of the device is introduced, which mainly includes the research work in laser-plasma interaction, high temperature explosion simulation, high pressure flying plate drive, solid material sound velocity measurement, X-ray framing camera performance assessment, multi-angle shock diagnosis target structure verification. Finally, the future application of the device is prospected. Copyright © 2024 SPIE.

关键词： Inertial confinement fusion

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