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Summary of Lagrangrian Transport Models of Radionuclides in the Marine Environment 30

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Summary of Lagrangrian Transport Models of Radionuclides in ...

30th International Conference on Nuclear engineering, ICONE 2023

作者： Qu, Zhengzhe Nie, Baojie Wang, Liang Fan, Zhixiang Fu, Jia Fan, Qunchao Xie, Feng Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University Beijing100084 China School of Nuclear Science and Engineering Shanghai Jiao Tong University Shanghai200240 China Nuclear and Radiation Safety Center Ministry of Ecology and Environment Beijing100082 China State Environmental Protection Key Laboratory of Nuclear and Radiation Safety Regulatory Simulation and Validation Beijing100082 China School of Physics and Chemistry Research Center for Advanced Computation Xihua University Chengdu610039 China

ISBN: (纸本)9784888982566

The transport of radionuclides in the marine has been a hot issue of social concern since the Fukushima accident, especially the Japanese government announced to discharge the wastewater from Fukushima Daiichi Nuclear Power Plant (FDNPP) into Pacific Ocean in 2021, which can directly affect the environment and human health. Regarding inland nuclear power plants, freshwater habitats such as reservoirs and rivers could also be polluted by the radioactive effluents. An adequate model is expected to be instrumental in assessing radioactive pollution in various water environments. Scientists have proposed various models to simulate the advection and diffusion of radionuclides released by the Fukushima nuclear accident in the marine in different marine environmental conditions. In this study, the behaviors of radionuclides in water bodies are introduced, including advection, turbulent mixing, decay, and interaction with sedimentss and biota. The processes of Lagrangian models, which are commonly used to simulate the transport of radionuclides in the marine, are explained in detail. The research progress and application examples of radionuclide transport models in rivers and marines in recent years are systematically summarized. Current research can provide suggestions for the development of numerical models for describing the transport behavior of radionuclides in the marine environment. © 2023 by JSME.

关键词： Radioisotopes

Projections of land use changes under the plant functional type classification in different SSP-RCP scenarios in China

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science Bulletin 2020年第22期65卷 1935-1947,M0004页

作者： Weilin Liao Xiaoping Liu Xiyun Xu Guangzhao Chen Xun Liang Honghui Zhang Xia Li Guangdong Key Laboratory for Urbanization and Geo-simulation School of Geography and PlanningSun Yat-sen UniversityGuangzhou 510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China School of Geography and Information Engineering China University of GeosciencesWuhan 430078China College of Resources and Environmental Sciences Hunan Normal UniversityChangsha 410081China Guangdong Guodi Planning Science Technology Co. LtdGuangzhou 510075China School of Geographic Sciences East China Normal UniversityShanghai 200241China

Land use projections are crucial for climate models to forecast the impacts of land use changes on the Earth’s ***,the spatial resolution of existing global land use projections(e.g.,0.25°×0.25°in the Land-Use Harmonization(LUH2)datasets)is still too coarse to drive regional climate models and assess mitigation effectiveness at regional and local *** generate a high-resolution land use product with the newest integrated scenarios of the shared socioeconomic pathways and the representative concentration pathways(SSPs-RCPs)for various regional climate studies in China,here we first conduct land use simulations with a newly developed Future Land Uses simulation(FLUS)model based on the trajectories of land use demands extracted from the LUH2 *** this basis,a new set of land use projections under the plant functional type(PFT)classification,with a temporal resolution of 5 years and a spatial resolution of 5 km,in eight SSP-RCP scenarios from 2015 to 2100 in China is *** results show that differences in land use dynamics under different SSP-RCP scenarios are jointly affected by global assumptions and national ***,with improved spatial resolution,the data produced in this study can sufficiently describe the details of land use distribution and better capture the spatial heterogeneity of different land use types at the regional *** highlight that these new land use projections at the PFT level have a strong potential for reducing uncertainty in the simulation of regional climate models with finer spatial resolutions.

关键词： Land use change Plant functional type Future Land Uses simulation(FLUS) Land use simulation SSP-RCP scenarios

A convergence analysis of a structure-preserving gradient flow method for the all-electron Kohn-Sham model

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arXiv 2023年

作者： Shen, Yedan Wang, Ting Zhou, Jie Hu, Guanghui School of Mathematics and Information Science Guangzhou University Guangzhou China Faculty of Science and Technology University of Macau China Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan China School of Mathematical Computational Sciences Xiangtan University Xiangtan China Zhuhai UM Science & Technology Research Institute Zhuhai China Guangdong-Hong Kong-Macao Joint Laboratory for Data-Driven Fluid Mechanics and Engineering Applications University of Macau China

In [Dai et al, Multi. Model. Simul., 2020], a structure-preserving gradient flow method was proposed for the ground state calculation in Kohn–Sham density functional theory, based on which a linearized method was developed in [Hu, et al, EAJAM, accepted] for further improving the numerical efficiency. In this paper, a complete convergence analysis is delivered for such a linearized method for the all-electron Kohn–Sham model. Temporally, the convergence, the asymptotic stability, as well as the structure-preserving property of the linearized numerical scheme in the method is discussed following previous works, while spatially, the convergence of the h-adaptive mesh method is demonstrated following [Chen et al, Multi. Model. Simul., 2014], with a key study on the boundedness of the Kohn–Sham potential for the all-electron Kohn–Sham model. Numerical examples confirm the theoretical results very well. Copyright © 2023, The Authors. All rights reserved.

关键词： Asymptotic stability

A novel dual-stage algorithm for capacitated arc routing problems with time-dependent service costs

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arXiv 2024年

作者： Li, Qingya Liu, Shengcai Zou, Juan Tang, Ke Guangdong Key Laboratory of Brain-Inspired Intelligent Computation Department of Computer Science and Engineering Southern University of Science and Technology Shenzhen518055 China The Key Laboratory of Hunan Province for Internet of Things and Information Security Xiangtan University Xiangtan411105 China The Key Laboratory of Intelligent Computing and Information Processing Ministry of Education Xiangtan University Xiangtan411105 China

This paper focuses on solving the capacitated arc routing problem with time-dependent service costs (CARPTDSC), which is motivated by winter gritting applications. In the current literature, exact algorithms designed for CARPTDSC can only handle small-scale instances, while heuristic algorithms fail to obtain high-quality solutions. To overcome these limitations, we propose a novel dual-stage algorithm, called MAENS-GN, that consists of a routing stage and a vehicle departure time optimization stage. The former obtains the routing plan, while the the latter determines the vehicle departure time. Importantly, existing literature often ignores the characteristic information contained in the relationship between the route cost and the vehicle departure time. The most significant innovation in this paper lies in the exploitation of this characteristic information during the vehicle departure time optimization stage. Specifically, we conduct a detailed analysis of this relationship under various scenarios and employ tailored methods to obtain the (approximately) optimal vehicle departure time. Furthermore, we propose an improved initialization strategy that considers time-dependent characteristics to achieve better solution quality. In addition to the modified benchmark test sets, we also experiment on a real-world test set. Experimental results demonstrate that MAENS-GN can obtain high-quality solutions on both small-scale and larger-scale instances of CARPTDSC. Copyright © 2024, The Authors. All rights reserved.

关键词： Combinatorial optimization

A Novel Dual-Stage Algorithm for Capacitated Arc Routing Problems with Time-Dependent Service Costs

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SSRN

SSRN 2024年

This paper focuses on solving the capacitated arc routing problem with time-dependent service costs (CARPTDSC), which is motivated by winter gritting applications. In the current literature, exact algorithms designed for CARPTDSC can only handle small-scale instances, while heuristic algorithms fail to obtain high-quality solutions. To overcome these limitations, we propose a novel dual-stage algorithm, called MAENS-GN, that consists of a routing stage and a vehicle departure time optimization stage. The former obtains the routing plan, while the the latter determines the vehicle departure time. Importantly, existing literature often ignores the characteristic information contained in the relationship between the route cost and the vehicle departure time. The most signiﬁcant innovation in this paper lies in the exploitation of this characteristic information during the vehicle departure time optimization stage. Speciﬁcally, we conduct a detailed analysis of this relationship under various scenarios and employ tailored methods to obtain the (approximately) optimal vehicle departure time. Furthermore, we propose an improved initialization strategy that considers time-dependent characteristics to achieve better solution quality. In addition to the modiﬁed benchmark test sets, we also experiment on a real-world test set. Experimental results demonstrate that MAENS-GN can obtain high-quality solutions on both small-scale and larger-scale instances of CARPTDSC. © 2024, The Authors. All rights reserved.

关键词： Combinatorial optimization

UNCONDITIONALLY ENERGY STABLE IEQ-FEMS FOR THE CAHN-HILLIARD EQUATION AND ALLEN-CAHN EQUATION

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arXiv 2024年

作者： Chen, Yaoyao Liu, Hailiang Yi, Nianyu Yin, Peimeng School of Mathematics and Statistics Anhui Normal University Anhui Wuhu241000 China Department of Mathematics Iowa State University AmesIA50011 United States Hunan Key Laboratory for Computation and Simulation in Science and Engineering School of Mathematics and Computational Science Xiangtan University Hunan Xiangtan411105 China Department of Mathematical Sciences The University of Texas at El Paso El PasoTX79968 United States

In this paper, we present several unconditionally energy-stable invariant energy quadratization (IEQ) finite element methods (FEMs) with linear, first- and second-order accuracy for solving both the Cahn-Hilliard equation and the Allen-Cahn equation. For time discretization, we compare three distinct IEQ-FEM schemes that position the intermediate function introduced by the IEQ approach in different function spaces: finite element space, continuous function space, or a combination of these spaces. Rigorous proofs establishing the existence and uniqueness of the numerical solution, along with analyses of energy dissipation for both equations and mass conservation for the Cahn-Hilliard equation, are provided. The proposed schemes' accuracy, efficiency, and solution properties are demonstrated through numerical experiments. © 2024, CC BY-NC-ND.

关键词： Finite element method

A Bi-variant Variational Model for Diffeomorphic Image Registration with Relaxed Jacobian Determinant Constraints

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arXiv 2023年

作者： Li, Yanyan Chen, Ke Chen, Chong Zhang, Jianping School of Mathematics and Computational Science Xiangtan University Hunan Xiangtan411105 China Department of Mathematics and Statistics University of Strathclyde GlasgowG1 1XH United Kingdom LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing Beijing100190 China National Center for Applied Mathematics in Hunan Xiangtan University Hunan Xiangtan411105 China Hunan Key Laboratory for Computation and Simulation in Science and Engieering Xiangtan University Hunan Xiangtan411105 China

Diffeomorphic registration is a widely used technique for finding a smooth and invertible transformation between two coordinate systems, which are measured using template and reference images. The point-wise volume-preserving constraint det(∇φ(x)) = 1 is effective in some cases, but may be too restrictive in others, especially when local deformations are relatively large. This can result in poor matching when enforcing large local deformations. In this paper, we propose a new bi-variant diffeomorphic image registration model that introduces a soft constraint on the Jacobian equation det(∇φ(x)) = f(x) > 0. This allows local deformations to shrink and grow within a flexible range 0 M M. The Jacobian determinant of transformation is explicitly controlled by optimizing the relaxation function f(x). To prevent deformation folding and improve the smoothness of the transformation, a positive constraint is imposed on the optimization of the relaxation function f(x), and a regularizer is used to ensure the smoothness of f(x). Furthermore, the positivity constraint ensures that f(x) is as close to one as possible, which helps to achieve a volume-preserving transformation on average. We also analyze the existence of the minimizer for the variational model and propose a penalty-splitting algorithm with a multilevel strategy to solve this model. Numerical experiments demonstrate the convergence of the proposed algorithm and show that the positivity constraint can effectively control the range of relative volume without compromising the accuracy of the registration. Moreover, the proposed model generates diffeomorphic maps for large local deformations and outperforms several existing registration models in terms of *** Codes 54H30, 68U10, 94A08 Copyright © 2023, The Authors. All rights reserved.

关键词： Iterative methods

Engineered poly(A)-surrogates for translational regulation and therapeutic biocomputation in mammalian cells

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细胞研究（英文版） 2024年第1期34卷 31-46页

作者： Jiawei Shao Shichao Li Xinyuan Qiu Jian Jiang Lihang Zhang Pengli Wang Yaqing Si Yuhang Wu Minghui He Qiqi Xiong Liuqi Zhao Yilin Li Yuxuan Fan Mirta Viviani Yu Fu Chaohua Wu Ting Gao Lingyun Zhu Martin Fussenegger Hui Wang Mingqi Xie International Institutes of Medicine The Fourth Affiliated HospitalZhejiang University School of MedicineYiwuZhejiangChina Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province School of Life SciencesWestlake UniversityHangzhouZhejiangChina Westlake Laboratory of Life Sciences and Biomedicine HangzhouZhejiangChina Institute of Basic Medical Sciences Westlake Institute for Advanced StudyHangzhouZhejiangChina College of Life Sciences Zhejiang UniversityHangzhouZhejiangChina Department of Biology and Chemistry College of ScienceNational University of Defense TechnologyChangshaHunanChina Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province School of Life SciencesWestlake UniversityHangzhouZhejiangChina Westlake Laboratory of Life Sciences and Biomedicine HangzhouZhejiangChina Institute of Basic Medical Sciences Westlake Institute for Advanced StudyHangzhouZhejiangChina School of Life Sciences Fudan UniversityShanghaiChina Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province School of Life SciencesWestlake UniversityHangzhouZhejiangChina Westlake Laboratory of Life Sciences and Biomedicine HangzhouZhejiangChina Institute of Basic Medical Sciences Westlake Institute for Advanced StudyHangzhouZhejiangChina Research Center of Biological Computation Zhejiang LaboratoryHangzhouZhejiangChina Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province School of Life SciencesWestlake UniversityHangzhouZhejiangChina Westlake Laboratory of Life Sciences and Biomedicine HangzhouZhejiangChina Institute of Basic Medical Sciences Westlake Institute for Advanced StudyHangzhouZhejiangChina Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province School of Life SciencesWestlake UniversityHangzhouZhejiangChina Westlake Laboratory of Life Sciences and Biomedicine HangzhouZhejiangChina Institute of Basic Medical Sciences Westlake Institute

Here,we present a gene regulation strategy enabling programmable control over eukaryotic translational *** excising the natural poly-adenylation(poly-A)signal of target genes and replacing it with a synthetic control region harboring RNA-binding protein(RBP)-specific aptamers,cap-dependent translation is rendered exclusively dependent on synthetic translation initiation factors(STIFs)containing different RBPs engineered to conditionally associate with different elF4F-binding proteins(eIFBPs).This modular design framework facilitates the engineering of various gene switches and intracellular sensors responding to many user-defined trigger signals of interest,demonstrating tightly controlled,rapid and reversible regulation of transgene expression in mammalian cells as well as compatibility with various clinically applicable delivery routes of in vivo gene *** efficacy was demonstrated in two animal *** exemplify disease treatments that require on-demand drug secretion,we show that a custom-designed gene switch triggered by the FDA-approved drug grazoprevir can effectively control insulin expression and restore glucose homeostasis in diabetic *** diseases that require instantaneous sense-and-response treatment programs,we create highly specific sensors for various subcellularly(mis)localized protein markers(such as cancer-related fusion proteins)and show that translation-based protein sensors can be used either alone or in combination with other cell-state classification strategies to create therapeutic biocomputers driving self-sufficient elimination of tumor cells in *** design strategy demonstrates unprecedented flexibility for translational regulation and could form the basis for a novel class of programmable gene therapies in vivo.

关键词： Riboswitches Targeted therapies

High-fidelity fast quantum driving in nonlinear systems

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Physical Review A 2014年第1期89卷 012123-012123页

作者： F. Q. Dou L. B. Fu J. Liu Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province College of Physics and Electronic Engineering Northwest Normal University Lanzhou 730070 China School of Physics Beijing Institute of Technology Beijing 100081 China National Laboratory of Science and Technology on Computation Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China Key Laboratory of High Energy Density Physics Simulation (HEDPS) Center for Applied Physics and Technology Peking University Beijing 100084 China

We investigate high-fidelity quantum driving in a nonlinear two-level system and find that nonlinear atomic interaction can break the speed limit of the linear model. We show that repulsive atomic interaction can decrease the minimal time requested for reaching target state even to zero, while attractive atomic interaction tends to increase the minimal time. There exists a critical attractive interaction beyond which the target state cannot be reached with high fidelity. Possible experimental observation of the nonlinear effects using a Bose-Einstein condensate in an accelerating optical lattice is discussed.

关键词： QUANTUM states NONLINEAR systems ATOMIC interactions SPEED limits LINEAR models (Statistics) OPTICAL lattices