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A high fidelity general purpose 3-D Monte Carlo particle transport program JMCT3.0

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Nuclear Science and Techniques 2022年第8期33卷 175-192页

作者： Li Deng Gang Li Bao-Yin Zhang Rui Li Ling-Yu Zhang Xin Wang Yuan-Gang Fu Dun-Fu Shi Peng Liu Yan Ma Dan-Hu Shangguan Ze-Hua Hu Sheng-Cheng Zhou Jing-Wen Shen Institute of Applied Physics and Computational Mathematics(IAPCM) Beijing 100094China caep software Centre for high performance numerical simulation(caep-SCNS) Beijing 100088China

JMCT is a large-scale,high-fidelity,three-dimensional general neutron–photon–electron–proton transport Monte Carlo software *** was developed based on the combinatorial geometry parallel infrastructure JCOGIN and the adaptive structured mesh infrastructure *** is equipped with CAD modeling and visualizes the image *** supports the geometry of the body and the structured/unstructured *** has most functions,variance reduction techniques,and tallies of the traditional Monte Carlo particle transport *** energy models,multi-group and continuous,are *** recent years,some new functions and algorithms have been developed,such as Doppler broadening on-thefly(OTF),uniform tally density(UTD),consistent adjoint driven importance sampling(CADIS),fast criticality search of boron concentration(FCSBC)domain decomposition(DD),adaptive control rod moving(ACRM),and random geometry(RG)*** JMCT is also coupled with the discrete ordinate SNcode JSNT to generate source-biasing factors and weight-window *** present,the number of geometric bodies,materials,tallies,depletion zones,and parallel processors are sufficiently large to simulate extremely complicated device *** can be used to simulate reactor physics,criticality safety analysis,radiation shielding,detector response,nuclear well logging,and dosimetry calculations *** particular,JMCT can be coupled with depletion and thermal-hydraulics for the simulation of reactor nuclear-hot feedback *** paper describes the progress in advanced modeling,high-performance numerical simulation of particle transport,multiphysics coupled calculations,and large-scale parallel computing.

关键词： Advanced modeling high-performance numerical simulation Multi-physics coupled calculation Large-scale parallel computing JMCT

Design and optimization of a SiC thermal emitter/absorber composed of periodic microstructures based on a non-linear method

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Chinese Physics B 2015年第9期24卷 276-283页

作者：王卫杰赵振国赵艺周海京符策基 Institute of Applied Physics and Computational Mathematics software center for high performance numerical simulation of caep Complicated Electromagnetic Environment Laboratory of caep LTCS and Department of Mechanics and Engineering Science College of EngineeringPeking University

Spectral and directional control of thermal emission based on excitation of confined electromagnetic resonant modes paves a viable way for the design and construction of microscale thermal emitters/absorbers. In this paper, we present numerical simulation results of the thermal radiative properties of a silicon carbide（Si C） thermal emitter/absorber composed of periodic microstructures. We illustrate different electromagnetic resonant modes which can be excited with the structure,such as surface phonon polaritons, magnetic polaritons and photonic crystal modes, and the process of radiation spectrum optimization based on a non-linear optimization algorithm. We show that the spectral and directional control of thermal emission/absorption can be efficiently achieved by adjusting the geometrical parameters of the structure. Moreover, the optimized spectrum is insensitive to 3% dimension modification.

关键词： silicon carbide radiative heat transfer photonic crystal optimization method

Study on the Estimation of Groundwater Withdrawals Based on Groundwater Flow Modeling and Its Application in the North China Plain

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Journal of Earth Science 2014年第6期25卷 1033-1042页

作者： Jingli Shao Yali Cui Qichen Hao Zhong Han Tangpei Cheng School of Water Resources and Environment China University of Geosciences Institute of Applied Physics and Computational Mathematics caep software center for high performance numerical simulation

The amount of water withdrawn by wells is one of the quantitative variables that can be applied to estimate groundwater resources and further evaluate the human influence on groundwater systems. The accuracy for the calculation of the amount of water withdrawal significantly influences the regional groundwater resource evaluation and management. However, the decentralized groundwater pumping, inefficient management, measurement errors and uncertainties have resulted in considerable errors in the groundwater withdrawal estimation. In this study, to improve the estimation of the groundwater withdrawal, an innovative approach was proposed using an inversion method based on a regional groundwater flow numerical model, and this method was then applied in the North China Plain. The principle of the method was matching the simulated water levels with the observation ones by adjusting the amount of groundwater withdrawal. In addition, uncertainty analysis of hydraulic conductivity and specific yield for the estimation of the groundwater withdrawal was conducted. By using the proposed inversion method, the estimated annual average groundwater withdrawal was approximately 24.92×10^9 m^3 in the North China Plain from 2002 to 2008. The inversion method also significantly improved the simulation results for both hydrograph and the flow field. Results of the uncertainty analysis showed that the hydraulic conductivity was more sensitive to the inversion results than the specific yield.

关键词： inversion method North China Plain groundwater withdrawal numerical modeling

Parallel simulation of Groundwater Flow in the North China Plain

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Journal of Earth Science 2014年第6期25卷 1059-1066页

作者： Tangpei Cheng Jingli Shao Yali Cui Zeyao Mo Zhong Han Ling Li Institute of Applied Physics and Computational Mathematics caep software center for high performance numerical simulation School of Water Resources and Environmental Science China University of Geosciences

numerical modeling is of crucial importance in understanding the behavior of regional groundwater system. However, the demand on modeling capability is intensive when performing high-resolution simulation over long time span. This paper presents the application of a parallel program to speed up the detailed modeling of the groundwater flow system in the North China Plain. The parallel program is implemented by rebuilding the well-known MODFLOW program on our parallelcomputing framework, which is achieved by designing patch-based parallel data structures and algorithms but maintaining the compute flow and functionalities of MODFLOW. The detailed model with more than one million grids and a decade of time has been solved. The parallel simulation results were examined against the field observed data and these two data are generally in good agreement. For the comparison on solution time, the parallel program running on 32 cores is 6 times faster than the fastest MICCG-based MODFLOW program and 11 times faster than the GMG-based MODFLOW program. Therefore, remarkable computational time can be saved when using the parallel program, which facilitates the rapid modeling and prediction of the groundwater flow system in the North China Plain.

关键词： parallel computing groundwater flow modeling MODFLOW North China Plain

Extreme-scale parallel computing:bottlenecks and strategies

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Frontiers of Information Technology & Electronic Engineering 2018年第10期19卷 1251-1260页

作者： Ze-yao MO caep software center for high performance numerical simulation Institute of Applied Physics and Computational Mathematics

Extreme-scale numerical simulations seriously demand extreme parallel computing capabilities. To address the challenges of these capabilities toward exascale, we systematically analyze the major bottlenecks of parallel computing research from three perspectives： computational scale, computing efficiency, and programming productivity. For these bottlenecks, we propose a series of urgent key issues and coping strategies. This study will be useful in synchronizing development between the numerical computing capability and supercomputer peak performance.

关键词： Extreme scale numerical simulation Parallel computing Supercomputers

numerical study on micro-fracture mechanism of rock dynamic failureinduced by abrupt unloading under high in-situ stresses

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Theoretical & Applied Mechanics Letters 2024年第6期14卷 486-495页

作者： Yuezong Yang Anye Li Zhushan Shao Kui Wu Wei Wei Wenhui Du Yujie Wang School of Science Xi’an University of Architecture and TechnologyXi’an 710055China caep software center for high performance numerical simulation Institute of Applied Physics and Computational Mathematics BeijingBeijing 100088China

Rock burst is a kind of severe engineering disaster resulted from dynamic fracture process of *** macrofailure behaviors of rocks are primarily formed after experiencing the initiation,propagation,and coalescenceof *** this paper,the grain-based discretized virtual internal bond model is employed to investigatethe fracturing process of unloaded rock under high in-situ stresses from the micro-fracture *** micro-fracturing process reveals that the longitudinal stress waves induced by unloading lead to thevisible unloading *** influences of in-situ stresses,mineral grain sizes,and grain heterogeneity on rockmacro and micro fracture are ***-crack areas of tensile and shear cracks and micro-crack anglesare statistically analyzed to reveal the rock micro-fracture *** simulated results indicate thatthe combined effect of the stress state transition and the unloading effect dominates the rock unloading *** vertical and horizontal in-situ stresses determine the stress state of surrounding rock after unloading andthe unloading effect,*** the vertical stress increases,the stress level after unloading is higher,andthe shear failure characteristics become more *** the horizontal stress increases,the unloading effectincreases,leading to the intensification of tensile *** mineral grain size and grain heterogeneity alsohave nonnegligible influences on rock unloading *** micro-fracture perspective provides further insightinto the unloading failure mechanism of deep rock excavation.

关键词： Rock burst Micro-fracture Dynamic failure Unloading effect

Formation of a disordered region at the grain boundary during migration with He atoms

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Science China(Physics,Mechanics & Astronomy) 2017年第4期60卷 78-81页

作者： Shi Yuan Hu Yi Yu Wei Shi Yuan YuHan Wang XiaoLin Shu GuangHong Lu Department of Physics Beihang University Institute of Applied Physics & Computational Mathematics software center for high performance numerical simulation

W is considered a potential candidate as a plasma facing ma- terial for future nuclear fusion devices because of its high melting point, low sputtering rate, and low H or He solubility [1-3]. In a fusion environment, W will be in direct contact with heat flux, H/He particle fluxes, and the irradiation of high-energy neutrons, causing several defects to be generated, which decrease the service life of W materials. The grain boundary （GB）, which is an important type of defect, affects the various physical and mechanical properties of ma- terials. In the nuclear environment, the GB can act as a sink for the defects when the material is under irradiation.

关键词： migration sputtering solubility irradiation melting disordered defects candidate facing causing

TGMin： A global-minimum structure search program based on a constrained basin-hopping algorithm

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Nano Research 2017年第10期10卷 3407-3420页

作者： Yafan Zhao Xin Chen Jun Li Institute of Applied Physics and Computational Mathematics Beijing 100088 China caep software center for high performance numerical simulation Beijing 100088 China Department of Chemistry and Laboratory of Organic Optoelectronics & Molecular Engineering of the Ministry of Education Tsinghua University Beijing 100084 China

In this article, we introduce Tsinghua Global Minimum （TGMin） as a new program for the global minimum searching of geometric structures of gas-phase or surface-supported atomic clusters, and the constrained basin-hopping （BH） algorithm implemented in this program. To improve the efficiency of the BH algorithm, several types of constraints are introduced to reduce the vast search space, including constraints on the random displacement step size, displacement of low-coordination atoms, and geometrical structure adjustment after displacement. The ultrafast shape-recognition （USR） algorithm and its variants are implemented to identify duplicate structures during the global minimum search. In addition to the Metropolis acceptance criterion, we also implemented a morphology-based constraint that confines the global minimum search to a specific type of morphology, such as planar or non-planar structures, which offers a strict divide-and-conquer strategy for the BH algorithm. These improvements are implemented in the TGMin program, which was developed over the past decade and has been used in a number of publications. We tested our TGMin program on global minimum structural searches for a number of metal and main-group clusters including C60, Au20 and B20 clusters. Over the past five years, the TGMin program has been used to determine the global minimum structures of a series of boron atomic clusters （such as [B26]^-, [B28]^-, [B30]^-, [B35]^-, [B36]^-, [B39]^-, [B40]^-, [MnB16]^-, [COB18]^-, [RhB18]^-, and [TaB20]^-）, metal-containing clusters Lin （n = 3-20）, Aug（CO）8^＋ and [Cr6O19]^2-. and the oxide-supported metal catalyst Au7/γ-Al2O3, as well as other isolated and surface-supported atomic clusters. In this article we present the major features of TGMin program and show that it is highly efficient at searching for global-minimum structures of atomic clusters in the gas phase and on various surface supports.

关键词： basin hopping ultrafast shape recognition global minimum search density functional theory cluster

Element analysis method of concealed explosive based on TNA

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Nuclear Science and Techniques 2019年第1期30卷 19-25页

作者： Meng Huang Jian-Yu Zhu Jun Wu Rui Li Institute of Applied Physics and Computational Mathematics center for Strategic Studies China Academy of Engineering Physics software center for high performance numerical simulation China Academy of Engineering Physics

The detection technology of concealed bulk explosives is related to social security and national defense construction and has important research significance. In this paper, an element analysis method of concealed explosives based on thermal neutron analysis is *** method could provide better reconstruction precision for hydrogen, carbon, and nitrogen ratios, making it possible to discriminate explosives from other compounds with the same elements but different proportions, as well as to identify the types of concealed bulk explosives. In this paper, the basic principles and mathematical model of this method are first introduced, and the calculation formula of the element number ratio(the ratio between the nucleus numbers of two different elements) of the concealed explosive is deduced. Second, a numerical simulation platform of this method was established based on the Monte Carlo JMCT code. By calibrating the absorption efficiencies of the explosive device to c rays, the element number ratios of a concealed explosive model under the irradiation of thermal neutrons were reconstructed from the neutron capture prompt c-ray spectrum. The reconstruction values were in good agreement with the actual values,which shows that this method has a high reconstruction precision of the element number ratio for concealed explosives. Lastly, it was demonstrated using the simulation study that this method can discriminate explosives,drugs, and common materials, with the capability of determining the existence of concealed bulk explosives and identifying explosive types.

关键词： Concealed bulk explosive Explosive type identification TNA Element number ratio