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Correlation analysis in control rod worth uncertainty quantification

Correlation analysis in control rod worth uncertainty quanti...

2018 International Conference on Physics of Reactors: Reactor Physics Paving the Way Towards More Efficient Systems, PHYSOR 2018

作者： Wang, Yizhen Hao, Chen Wu, Yingjie Wang, Lidong Guo, Jiong Li, Fu Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University Beijing100084 China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Harbin150001 China

ISBN: (纸本)9781713808510

Precise calculation of control rod worth (CRW) is important for nuclear reactor core design which can be used to assess reactor shutdown margin, design reactivity insertion experiments and so on. Uncertainties inevitably exist in selected nuclear data library and these uncertainties will propagate to the keffand CRW. One of the issues in quantifying CRW uncertainty propagated from keffis the analysis of correlation among keffunder varying insertion depths of control rod. In this paper, based on sensitivities of keffto few-group macroscopic cross section, correlation coefficients among different keffare studied firstly. And a preliminary uncertainty quantification method of CRW is proposed with such correlation information of keffas well as their uncertainties resulting from nuclear data library. A mini core model is established and statistical sampling on CRW is conducted to validate the uncertainty of CRW obtained by the method proposed in this work. © 2018 International Conference on Physics of Reactors, PHYSOR 2018: Reactor Physics Paving the Way Towards More Efficient Systems. All rights reserved.

关键词： Reactor shutdowns

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Harnessing non-local orbital-to-spin conversion of interfacial orbital currents for efficient spin-orbit torques

arXiv

引用

arXiv 2020年

作者： Ding, Shilei Ross, Andrew Go, Dongwook Ren, Zengyao Freimuth, Frank Becker, Sven Kammerbauer, Fabian Yang, Jinbo Jakob, Gerhard Mokrousov, Yuriy Kläui, Mathias State Key Laboratory for Mesoscopic Physics School of Physics Peking University Beijing100871 China Institute of Physics Johannes Gutenberg-University Mainz Staudingerweg 7 Mainz55128 Germany Graduate School of Excellence Materials Science in Mainz Mainz55128 Germany Peter Grunberg Institut Institute for Advanced Simulation Forschungszentrum Jülich and JARA Jülich52425 Germany School of Materials Science and Engineering University of Science and Technology Beijing Beijing100083 China Collaborative Innovation Center of Quantum Matter Beijing100871 China Beijing Key Laboratory for Magnetoelectric Materials and Devices Beijing100871 China Center for Quantum Spintronics Department of Physics Norwegian University of Science and Technology TrondheimNO-7491 Norway

Current induced spin-orbit torques (SOT) allow for the efficient electrical manipulation of magnetism in spintronic devices. Engineering the SOT efficiency is a key goal that is pursued by maximizing the active interfacial spin accumulation or modulating the non-equilibrium spin-density that builds up through the spin Hall and inverse spin galvanic effects. Regardless of the origin, the fundamental requirement for the generation of the current-induced torques is a net spin accumulation. Here, we report the large enhancement of the SOT efficiency in TmIG / Pt by capping with a CuOx layer. Considering the weak spin-orbit coupling (SOC) of CuOx, these surprising findings are explained as a result of orbital current generated from CuOx in contact with Pt. This interface-generated orbital current is injected into Pt and converted into a spin current due to the large SOC of Pt. The converted spin current decays across the Pt and exerts a "non-local" torque on TmIG. This additional torque leads to a maximum enhancement of the SOT efficiency of a factor 16 for 1.5 nm of Pt at room temperature, thus opening a path to increase torques while at the same time offering insights into the underlying physics of orbital transport which has been elusive so far. Copyright © 2020, The Authors. All rights reserved.

关键词： Torque

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Spin-Triplet Excitonic Insulator: The Case of Semihydrogenated Graphene

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Physical Review Letters 2020年第16期124卷 166401-166401页

作者： Zeyu Jiang Wenkai Lou Yu Liu Yuanchang Li Haifeng Song Kai Chang Wenhui Duan Shengbai Zhang State Key Laboratory of Low-Dimensional Quantum Physics and Collaborative Innovation Center of Quantum Matter Department of Physics Tsinghua University Beijing 100084 China SKLSM Institute of Semiconductors Chinese Academy of Sciences P.O. Box 912 Beijing 100083 China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China Key Lab of advanced optoelectronic quantum architecture and measurement (MOE) and Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing 100081 China CAEP Software Center for High Performance Numerical Simulation Beijing 100088 China Beijing Academy of Quantum Information Sciences Beijing 100193 China Institute for Advanced Study Tsinghua University Beijing 100084 China Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 USA

While various excitonic insulators have been studied in the literature, due to the perceived too-small spin splitting, spin-triplet excitonic insulator is rare. In two-dimensional systems such as a semihydrogenated graphene (known as graphone), however, it is possible, as revealed by first-principles calculations coupled with Bethe-Salpeter equation. The critical temperature, given by an effective Hamiltonian, is 11.5 K. While detecting excitonic insulators is still a daunting challenge, the condensation of triplet excitons will result in spin superfluidity, which can be directly measured by a transport experiment. Nonlocal dielectric screening also leads to an unexpected phenomenon, namely, an indirect-to-direct transition crossover between single-particle band and exciton dispersion in the semihydrogenated graphene, which offers yet another test by experiment.

关键词： Excitons Graphene First-principles calculations

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Combination of ozonation and electrolysis process to enhance elimination of thirty structurally diverse pharmaceuticals in aqueous solution

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Journal of hazardous materials 2019年 368卷 281-291页

作者： Xiang Li Yujue Wang Bin Wang Jun Huang Shubo Deng Gang Yu Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing 100081 China School of Environment State Key Joint Laboratory of Environmental Simulation and Pollution Control Beijing Key Laboratory for Emerging Organic Contaminants Control Tsinghua University Beijing 100084 China. School of Environment State Key Joint Laboratory of Environmental Simulation and Pollution Control Beijing Key Laboratory for Emerging Organic Contaminants Control Tsinghua University Beijing 100084 China. School of Environment State Key Joint Laboratory of Environmental Simulation and Pollution Control Beijing Key Laboratory for Emerging Organic Contaminants Control Tsinghua University Beijing 100084 China. Electronic address: yg-den@***.

The increasing amounts of pharmaceuticals in aqueous environment are found to be structurally diverse. O has been demonstrated as a high effective agent in removing pharmaceuticals, however, O is a very selective oxidant which is ineffective for some ozone refractory structures. Recently, a novel electrochemistry-based oxidation process (E-peroxone) has been developed by a simple combination of electrolysis and conventional ozonation process, which can produce a large amount of aqueous OH in situ. E-peroxone process can enhance the performance of conventional ozonation process. The purpose of this study was to investigate the elimination performance of thirty pharmaceuticals with various chemical structures including macrolide, quinolone, sulfonamides, tetracycline, carboxylic group, Naphthalene, Nitrogen-containing group, CC double bond in electrolysis, ozonation and E-peroxone process. Parent pharmaceuticals and TOC elimination were compared. By comparing different chemical groups, the synergy effect of pharmaceuticals with carboxylic and amide groups were significant, with average degradation level 98.7 ± 2.8% within 15 min. Degradation levels of some groups were quite efficient during both ozonation and E-peroxone process, such as macrolide, quinolone, sulfonamides and tetracycline. E-peroxone process improved the TOC and acute toxicity elimination efficiency of mixed pharmaceutical solutions significantly. Major operation parameters and cross correlation analysis were also evaluated.

关键词： Chemical structure Degradation Ozonation Pharmaceuticals Synergy

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Influence of secondary droplet on separation performance of wave-type vane separator 3

Influence of secondary droplet on separation performance of ...

引用

3rd International Conference on New Energy and Future Energy System, NEFES 2018

作者： Zhao, F.L. Liu, Q.F. Zhang, F. Li, J.X. Bo, H.L. Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University HEILONGJIANG150001 China Institute of Nuclear and New Energy Technology Tsinghua University Key Laboratory of Advanced Reactor Engineering and Safety Ministry of Education Beijing100084 China

The steam-water separator is a vital device of the steam generator in nuclear power plant. Its separation performance greatly influences the efficiency, safety and reliability of the power station. When the droplet moves in separator, the droplet can collide with the separator wall, and the secondary droplets may generate when the collision velocity of the primary droplet is sufficiently large. To investigate the effect of secondary droplet on separation performance of the separator, the simulation is conducted using droplet motion model and generation model of secondary droplet. The trajectories of both primary droplet and secondary droplet are presented. The effect of the secondary droplet on the separator separation efficiency is analyzed. The results can guide the design of the separator, where both of the droplet motion and the secondary droplets generation need to be considered. © Published under licence by IOP Publishing Ltd.

关键词： Separators

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Constraints on the two-dimensional pseudo-spin 1/2 Mott insulator description of Sr2IrO4

arXiv

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arXiv 2022年

作者： Zwartsenberg, Berend Day, Ryan P. Razzoli, Elia Michiardi, Matteo Na, Meng Xing Zhang, Guoren Denlinger, Jonathan D. Vobornik, Ivana Bigi, Chiara Kim, Bum Joon Elfimov, Ilya S. Pavarini, Eva Damascelli, Andrea Quantum Matter Institute University of British Columbia VancouverBCV6T 1Z4 Canada Department of Physics and Astronomy University of British Columbia VancouverBCV6T 1Z1 Canada Max Planck Institute for Chemical Physics of Solids Nöthnitzer Straße 40 Dresden01187 Germany Key Laboratory of Materials Physics Institute of Solid State Physics Hfips Chinese Academy of Sciences Hefei230031 China Advanced Light Source Lawrence Berkeley National Laboratory BerkeleyCA94720 United States -CNR Laboratorio Tasc Area Science Park S.S.14 Km 163.5 TriesteI-34149 Italy Dipartimento di Fisica Universitá di Milano Via Celoria 16 MilanoI-20133 Italy Department of Physics Pohang University of Science and Technology Pohang790-784 Korea Republic of 77 Cheongam-Ro Pohang790-784 Korea Republic of Max Planck Institute for Solid State Research Heisenbergstraße 1 StuttgartD-70569 Germany Institute for Advanced Simulation Forschungszentrum Jülich JülichD-52425 Germany Jara High-Performance Computing Forschungszentrum Jülich Jülich Germany

Sr2IrO4has often been described via a simple, one-band pseudo-spin 1/2 model, subject to electron-electron interactions, on a square lattice, fostering analogies with cuprate superconductors, believed to be well described by a similar model. In this work we argue - based on a detailed study of the low-energy electronic structure by circularly polarized spin and angle-resolved photoemission spectroscopy combined with dynamical mean-field theory calculations - that a pseudo-spin 1/2 model fails to capture the full complexity of the system. We show instead that a realistic multi-band Hubbard Hamiltonian, accounting for the full correlated t2gmanifold, provides a detailed description of the interplay between spin-orbital entanglement and electron-electron interactions, and yields quantitative agreement with experiments. Our analysis establishes that the j3/2states make up a substantial percentage of the low energy spectral weight, i.e. approximately 74% as determined from the integration of the j-resolved spectral function in the 0 to -1.64 eV energy range. The results in our work are not only of relevance to iridium based materials, but more generally to the study of multi-orbital materials with closely spaced energy scales. © 2022, CC BY-NC-ND.

关键词： Electron-electron interactions

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Combustion microstructures and frictional ignition resistance of Ti-6Al-4V titanium alloy

Combustion microstructures and frictional ignition resistanc...

引用

Chinese Materials Conference, 2018

作者： Mi, Guangbao Huang, Xu Cao, Jingxia Wang, Bao Cao, Chunxiao Aviation Key Laboratory of Science and Technology on Advanced Titanium Alloys Beijing Institute of Aeronautical Materials Beijing100095 China Beijing Engineering Research Center of Graphene and Application Beijing100095 China

ISBN: (纸本)9783035713848

The effects of the contact pressure Pfric and the oxygen concentration c0 on the ignition resistance of Ti-6Al-4V were studied by friction in oxygen-enriched atmosphere. The relationship of Pfric-c0 was built to quantitatively describe the ignition resistance, the combustion microstructures were investigated by XRD, SEM and EDS. Further, the principle of improving the ignition resistance was proposed. It indicates that the relationship of Pfric-c0 obeys parabolic law. The c0 decreases by 4% when the Pfric increases from 0.1MPa to 0.25MPa, manifesting that the ignition resistance depends on c0 strongly (or equivalent flow pressure Peq). The ignition resistance of Ti-6Al-4V is 42.9% of that of TB12. When Peq varies from 0.1~0.5MPa, the critical ignition temperature * is approximate to 568~461K. Violent sparks form during frictional ignition. The low ignition resistance of Ti-6Al-4V probably results from not only the composite oxides of TiO2, Al2 O3 and V2 O5 generating during ignition which could not prevent the rapid interaction between Ti and O, but also the Al and V elements in the heat-affected zone which could not stop or slow the massive diffusion of O towards the alloy. © 2019 Trans Tech Publications, Switzerland.

关键词： Microstructure

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Double annealing processes of Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloy

Double annealing processes of Ti-5Al-5Mo-5V-1Cr-1Fe titanium...

引用

Chinese Materials Conference, 2018

作者： Wang, Qingrui Sha, Aixue Huang, Lijun Li, Xingwu Mi, Guangbao Aviation Key Laboratory of Science and Technology on Advanced Titanium Alloys Beijing Institute of Aeronautical Materials Beijing100095 China Beijing Engineering Research Center of Graphene and Application Beijing100095 China

ISBN: (纸本)9783035713848

In this work, double annealing processes of Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloy were systemically investigated, and the microstructure and property of different processes were compared. The results show that, when the first stage annealing is air cooling, the microstructure with continuous and straight grain boundary is obtained, and corresponding mechanical property is not very good. When the first stage annealing is furnace cooling, the influence of first stage annealing temperature on microstructure and property is obvious. Excellent comprehensive property can be obtained when β grain boundary and α phase are discontinuous and tortuous. Further, based on this research, a new double annealing process is developed, which can obtain excellent ductility when large size forging is fabricated above the phase transformation point and has small deformation. © 2019 Trans Tech Publications, Switzerland.

关键词： Annealing

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Generalized Collision-free Velocity Model for Pedestrian Dynamics

arXiv

引用

arXiv 2019年

作者： Xu, Qiancheng Chraibi, Mohcine Tordeux, Antoine Zhang, Jun Institute for Advanced Simulation Forschungszentrum Jülich GmbH Jülich52425 Germany School of Mechanical Engineering and Safety Engineering University of Wuppertal Wuppertal42119 Germany State Key Laboratory of Fire Science University of Science and Technology of China Hefei230027 China

The collision-free velocity model is a microscopic pedestrian model, which despite its simplicity, reproduces fairly well several self-organization phenomena in pedestrian dynamics. The model consists of two components: a direction sub-model that combines individual desired moving direction and neighbour’s influence to imitate the process of navigating in a two-dimensional space, and an intrinsically collision-free speed sub-model which controls the speed of the agents with respect to the distance to their neighbors. This paper generalizes the collision-free velocity model by introducing the influence of walls and extending the distance calculations to velocity-based ellipses. Besides, we introduce enhancements to the direction sub-module of the model that smooth the direction changes of pedestrians in the simulation;a shortcoming that was not visible in the original model due to the symmetry of the circular shapes. Moreover, the introduced improvements mitigate backward movement, leading to a more realistic distribution of pedestrians especially in bottleneck scenarios. We study by simulation the effects of the pedestrian’s shape by comparing the fundamental diagram in narrow and wide corridors. Furthermore, we validate our enhancements to the direction sub-model for bottleneck experiments with varying exit’s width. Copyright © 2019, The Authors. All rights reserved.

关键词： Velocity

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Corrigendum: provincial-scale assessment of direct air capture to meet China’s climate neutrality goal under limited bioenergy supply (2024 Environ. Res. Lett. 19 114021)

引用

Environmental Research Letters 2025年第2期20卷 029502-029502页

作者： Hanwoong Kim Yang Qiu Haewon McJeon Andres Clarens Parisa Javadi Can Wang Rui Wang Jiachen Wang Hanying Jiang Andy Miller Ryna Cui Jenna Behrendt Yang Ou Sha Yu Jay Fuhrman Joint Global Change Research Institute University of Maryland and Pacific Northwest National Laboratory College Park MD 20740 United States of America Graduate School of Green Growth and Sustainability (GGGS) Korea Advanced Institute of Science and Technology 291 Daehak-ro Yuseong-gu Daejeon 34141 Republic of Korea University of Virginia Department of Civil and Environmental Engineering University of Virginia Charlottesville VA 22904 United States of America State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 People’s Republic of China Department of Earth System Science Ministry of Education Key Laboratory for Earth System Modelling Institute for Global Change Studies Tsinghua University Beijing 100084 People’s Republic of China Center for Global Sustainability School of Public Policy University of Maryland College Park MD United States of America College of Environmental Sciences and Engineering Peking University Beijing People’s Republic of China Institute of Carbon Neutrality Peking University Beijing People’s Republic of China

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