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Nuclear Science and Techniques 2023年第10期34卷 178-200页

作者： Qi-Hong Yang Yu Yang Yang-Tao Deng qiao-lin he he-lin Gong Shi-Quan Zhang School of Mathdematics Sichuan UniversityChengdu 610065China Paris Elite Institute of Technology Shanghai Jiao Tong UniversityShanghai 200240China

Machine learning-based modeling of reactor physics problems has attracted increasing interest in recent *** some progress in one-dimensional problems,there is still a paucity of benchmark studies that are easy to solve using traditional numerical methods albeit still challenging using neural networks for a wide range of practical *** present two networks,namely the Generalized Inverse Power Method Neural Network(GIPMNN)and Physics-Constrained GIPMNN(PC-GIPIMNN)to solve K-eigenvalue problems in neutron diffusion *** follows the main idea of the inverse power method and determines the lowest eigenvalue using an iterative *** PC-GIPMNN additionally enforces conservative interface conditions for the neutron ***,Deep Ritz Method(DRM)directly solves the smallest eigenvalue by minimizing the eigenvalue in Rayleigh quotient form.A comprehensive study was conducted using GIPMNN,PC-GIPMNN,and DRM to solve problems of complex spatial geometry with variant material domains from the fleld of nuclear reactor *** methods were compared with the standard flnite element *** applicability and accuracy of the methods are reported and indicate that PC-GIPMNN outperforms GIPMNN and DRM.

关键词： Neural network Reactor physics Neutron diffusion equation Eigenvalue problem Inverse power method

Navier-Stokes/Allen-Cahn System with Generalized Navier Boundary Condition

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Acta Mathematicae Applicatae Sinica 2022年第1期38卷 98-115页

作者： Ya-zhou CheN qiao-lin he Bin HUANG Xiao-ding SHI Department of Mathematics College of Mathematics and PhysicsBeijing University of Chemical TechnologyBeijing 100029China School of Mathematics Sichuan UniversityChengdu 610065China

In this paper,we focus on the immiscible compressible two-phase flow described by the coupled compressible Navier-Stokes system and the modified Allen-Cahn *** generalized Navier boundary condition and the relaxation boundary condition are established in order to solve the problem of moving contact lines on the solid boundary by using the principle of minimum energy *** existence and uniqueness for local strong solution in three dimensional bounded domain for this type of boundary value problem is obtained by the elementary energy method and the maximum principle.

关键词： compressible Navier-Stokes equation Allen-Cahn equation generalized Navier boundary condition existence uniqueness

Unsteady Flow of Shear-Thinning non-Newtonian Incompressible Fluid Through a Twin-Screw Extruder

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Acta Mathematicae Applicatae Sinica 2016年第2期32卷 423-436页

作者： Ya-zhou CheN qiao-lin he Xiao-ding SHI Teng WANG Bing ZHANG School of Mathematical Sciences Capital Normal University College of Science Beijing University of Chemical Technology College of Mathematics Sichuan University College of Science Beijing Forestry University CMEE Beijing University of Chemical Technology

The unsteady flow of viscous incompressible shear-thinning non-Newtonian fluid with mixed bound- ary is investigated. The boundary condition on the outflow is the modified natural boundary condition, it con- tains the additional nonlinear term, which enables us to control the kinetic energy of the backward flow. The global existence of weak solution is proved. The fictitious domain method which consists in filling the moving rigid screws with the surrounding fluid and taking into account the boundary conditions on these bodies by introducing a well-chosen distribution of boundary forces is used.

关键词： Shear-thinning incompressible fluid mixed boundary problem twin-screw extruder

On the Motion of Shear-Thinning heat-Conducting Incompressible Fluid-Rigid System

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Acta Mathematicae Applicatae Sinica 2018年第3期34卷 534-552页

作者： Ya-zhou CheN qiao-lin he Xiao-ding SHI Teng WANG Xiao-ping WANG Faculty of Science Beijing University of Chemical Technology Beijing 100029 China School of Mathematics Sichuan University Sichuan 610065 China College of Applied Sciences Beijing University of Technology Beijing100124 China Department of Mathematics Hong Kong University of Science and Technology H.K. China

The full Navier-Stokes-Fourier system with mixed boundary condition that describes the motion of shear-thinning and incompressible viscous fluid in a rotating multi-screw extruder is investigated. The viscosity is assumed to depend on the shear rate and the temperature. The global existence of suitable weak solutions is established. The fictitious domain method which consists in filling the moving rigid screws with the surrounding fluid and taking into account the boundary conditions on these bodies by introducing a well-chosen distribution of boundary forces is used.

关键词： shear-thinning heat-conducting incompressible fluid suitable weak solution

Impact Force Localization and Reconstruction via ADMM-based Sparse Regularization Method

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 170-188页

作者： Yanan Wang lin Chen Junjiang Liu Baijie qiao Weifeng he Xuefeng Chen National Key Lab of Aerospace Power System and Plasma Technology Xi’an Jiaotong UniversityXi’an 710049China School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China

In practice,simultaneous impact localization and time history reconstruction can hardly be achieved,due to the illposed and under-determined problems induced by the constrained and harsh measuring *** l_(1) regularization can be used to obtain sparse solutions,it tends to underestimate solution amplitudes as a biased *** address this issue,a novel impact force identification method with l_(p) regularization is proposed in this paper,using the alternating direction method of multipliers(ADMM).By decomposing the complex primal problem into sub-problems solvable in parallel via proximal operators,ADMM can address the challenge *** mitigate the sensitivity to regularization parameters,an adaptive regularization parameter is derived based on the K-sparsity ***,an ADMM-based sparse regularization method is developed,which is capable of handling l_(p) regularization with arbitrary p values using adaptively-updated *** effectiveness and performance of the proposed method are validated on an aircraft skin-like composite ***,an investigation into the optimal p value for achieving high-accuracy solutions via l_(p) regularization is *** turns out that l_(0.6)regularization consistently yields sparser and more accurate solutions for impact force identification compared to the classic l_(1) regularization *** impact force identification method proposed in this paper can simultaneously reconstruct impact time history with high accuracy and accurately localize the impact using an under-determined sensor configuration.

关键词： Impact force identification Non-convex sparse regularization Alternating direction method of multipliers Proximal operators

Spin effect on redox acceleration and regioselectivity in Fe-catalyzed alkyne hydrosilylation

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National Science Review 2024年第2期11卷 155-167页

作者： Peng he Meng-Yang Hu Jin-Hong Li Tian-Zhang qiao Yi-lin Lu Shou-Fei Zhu Frontiers Science Center for New Organic Matter State Key Laboratory and Institute of Elemento-Organic Chemistry Nankai University

Iron catalysts are ideal transition metal catalysts because of the Earths abundant, cheap, biocompatible features of iron salts. Iron catalysts often have unique open-shell structures that easily undergo spin crossover in chemical transformations, a feature rarely found in noble metal catalysts. Unfortunately, little is known currently about how the open-shell structure and spin crossover affect the reactivity and selectivity of iron catalysts, which makes the development of iron catalysts a low efficient trial-and-error program. In this paper, a combination of experiments and theoretical calculations revealed that the iron-catalyzed hydrosilylation of alkynes is typical spin-crossover catalysis. Deep insight into the electronic structures of a set of well-defined open-shell active formal Fe(0) catalysts revealed that the spin-delocalization between the iron center and the 1,10-phenanthroline ligand effectively regulates the iron center's spin and oxidation state to meet the opposite electrostatic requirements of oxidative addition and reductive elimination, respectively,and the spin crossover is essential for this electron transfer process. The triplet transition state was essential for achieving high regioselectivity through tuning the nonbonding interactions. These findings provide an important reference for understanding the effect of catalyst spin state on reaction. It is inspiring for the development of iron catalysts and other Earth-abundant metal catalysts, especially from the point of view of ligand development.

关键词： spin effect spin-delocalization spin crossover iron-catalysis alkyne hydrosilylation

Monte Carlo method for evaluation of surface emission rate measurement uncertainty

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Nuclear Science and Techniques 2024年第7期35卷 126-136页

作者： Yuan-qiao Li Min lin Li-Jun Xu Rui Luo Yu-he Zhang Qian-Xi Ni Yun-Tao Liu China Institute of Atomic Energy Beijing102413China National Key Laboratory for Metrology and Calibration Techniques Beijing102413China Department of Radiation Oncology Hunan Cancer HospitalChangsha410031China The Affiliated Cancer Hospital of Xiangya School of Medicine Central South UniversityChangsha410031China

The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter *** study used the Monte Carlo method (MCM) to validate the conventional Guide to the Expression of Uncertainty in Measurement (GUM) method.A dead time measurement model for the two-source method was established based on the characteristics of a single-channel measurement system,and the voltage threshold correction factor measurement function was indirectly obtained by fitting the threshold correction *** uncertainty in the surface emission rate was calculated using the GUM method and the law of propagation of *** MCM provided clear definitions for each input quantity and its uncertainty distribution,and the simulation training was realized with a complete and complex mathematical *** results of the surface emission rate uncertainty evaluation for four radioactive plane sources using both methods showed the uncertainty’s consistency E_(n)he comparison of each source,and the uncertainty results of the GUM were all lower than those of the ***,the MCM has a more objective evaluation process and can serve as a validation tool for GUM results.

关键词： Surface emission rate Monte Carlo method Metrology Probability distribution function Dead time Low-energy loss correction Least-squares method

Adversarial attacks and defenses for digital communication signals identification

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Digital Communications and Networks 2024年第3期10卷 756-764页

作者： qiao Tian Sicheng Zhang Shiwen Mao Yun lin College of Computer Science and Technology Harbin Engineering UniversityHarbin150001China College of Information and Communication Engineering Harbin Engineering UniversityHarbin150000China Department of Electrical and Computer Engineering Auburn UniversityAuburnAL36849USA

As modern communication technology advances apace,the digital communication signals identification plays an important role in cognitive radio networks,the communication monitoring and management *** has become a promising solution to this problem due to its powerful modeling capability,which has become a consensus in academia and ***,because of the data-dependence and inexplicability of AI models and the openness of electromagnetic space,the physical layer digital communication signals identification model is threatened by adversarial *** examples pose a common threat to AI models,where well-designed and slight perturbations added to input data can cause wrong ***,the security of AI models for the digital communication signals identification is the premise of its efficient and credible *** this paper,we first launch adversarial attacks on the end-to-end AI model for automatic modulation classifi-cation,and then we explain and present three defense mechanisms based on the adversarial *** we present more detailed adversarial indicators to evaluate attack and defense ***,a demonstration verification system is developed to show that the adversarial attack is a real threat to the digital communication signals identification model,which should be paid more attention in future research.

关键词： Digital communication signals identification AI model Adversarial attacks Adversarial defenses Adversarial indicators

NFXL1 functions as a transcriptional activator required for thermotolerance at reproductive stage in Arabidopsis

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Journal of Integrative Plant Biology 2024年第1期66卷 54-65页

作者： qiao‐Yun Zhu lin‐lin Zhang Jian‐Xiang Liu State Key Laboratory of Plant Environmental Resilience College of Life SciencesZhejiang UniversityHangzhou 310027China

Plants are highly susceptible to abiotic stresses,particularly heat stress during the reproductive ***,the specific molecular mechanisms underlying this sensitivity remain largely *** the current study,we demonstrate that the Nuclear Transcription Factor,X-box Binding Protein 1-Like 1(NFXL1),directly regulates the expression of DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN 2A(DREB2A),which is crucial for reproductive thermotolerance in ***1 is upregulated by heat stress,and its mutation leads to a reduction in silique length(seed number)under heat stress ***-Seq analysis reveals that NFXL1 has a global impact on the expression of heat stress responsive genes,including DREB2A,heat Shock Factor A3(HSFA3)and heat Shock Protein 17.6(HSP17.6)in flower ***,NFXL1 is enriched in the promoter region of DREB2A,but not of either HSFA3 or *** experiments using electrophoretic mobility shift assay have confirmed that NFXL1 directly binds to the DNA fragment derived from the DREB2A ***,effector-reporter assays have shown that NFXL1 activates the DREB2A *** DREB2A mutants are also heat stress sensitive at the reproductive stage,and DEREB2A is epistatic to NFXL1 in regulating thermotolerance in flower *** is known that HSFA3,a direct target of DREB2A,regulates the expression of heat shock proteins genes under heat stress ***,our findings establish NFXL1 as a critical upstream regulator of DREB2A in the transcriptional cassette responsible for heat stress responses required for reproductive thermotolerance in Arabidopsis.

关键词： Arabidopsis DREB2A heat stress NFXL1 reproductive thermotolerance

Study of primordial deuterium abundance in Big Bang nucleosynthesis

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Nuclear Science and Techniques 2024年第3期35卷 208-215页

作者： Zhi-lin Shen Jian-Jun he Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of Radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China

Big Bang nucleosynthesis(BBN)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)he,^(4)he,and^(7) Li produced in the early *** these,deuterium,the first nuclide produced by BBN,is a key primordial material for subsequent *** date,the uncertainty in predicted deuterium abundance(D/H)remains larger than the observational *** this study,the Monte Carlo simulation code PRIMAT was used to investigate the sensitivity of 11 important BBN reactions to deuterium *** found that the reaction rate uncertainties of the four reactions d(d,n)^(3)he,d(d,p)t,d(p,γ)^(3)he,and p(n,γ)d had the largest influence on the calculated D/H ***,the calculated D/H uncertainty cannot reach observational precision even with the recent LUNA precise d(p,γ)^(3) he *** the nuclear physics aspect,there is still room to largely reduce the reaction-rate uncertainties;hence,further measurements of the important reactions involved in BBN are still necessary.A photodisintegration experiment will be conducted at the Shanghai Laser Electron Gamma Source Facility to precisely study the deuterium production reaction of p(n,γ)d.

关键词： Big Bang nucleosynthesis Abundance of deuterium Reaction cross section Reaction rate Monte Carlo method