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Long-range behavior of a nonlocal correlation-energy density functional based on the random-phase approximation

Physical Review B 2020年第3期101卷 035113-035113页

作者： Yuan Gao Wenguang Zhu Xinguo Ren International Center for Quantum Design of Functional Materials (ICQD) Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China Hefei Anhui 230026 China CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei Anhui 230026 China

We propose a density-based nonlocal correlation energy functional, corresponding to a revised form of the seamless van der Waals (vdW) density functional developed by Dobson and coauthors in the late nineties. The functional, termed as rDW99 in this work, has the same energy expression as the random phase approximation (RPA), but its key ingredient—the noninteracting density response function—is expressed entirely in terms of the electron density and density gradient. This is enabled by generalizing the Lindhard function from the homogeneous electron gas (HEG) to inhomogeneous electron systems. Compared to the original DW99 functional of Dobson and coauthors, we have introduced two revisions in rDW99: (1) A gap correction is incorporated into the generalized Lindhard function, making the functional more suitable for describing inhomogeneous, and in particular insulating, systems; (2) an approximate, yet fairly accurate, analytical form of the Lindhard function in real space is developed which facilitates the numerical evaluation of the rDW99 functional. In contrast with previously developed vdW density functionals, the nonlocal polarization effect is naturally captured in the rDW99 functional. The functional form, as it stands right now, is computationally still rather involving in a straightforward implementation. However, we anticipate that numerical techniques can be developed to significantly reduce the computational cost. As a first step, we assess the quality of rDW99 for describing the vdW interactions in the nonoverlapping asymptotic regime by computing the C6 coefficients for a set of 43 atoms and molecules. With only one adjustable parameter, the mean absolute percentage error (MAPE) of the C6 coefficients is estimated to be 8.7%. In this work, C6 coefficients corresponding to the standard RPA method are also computed for the same test set, and the MAPE for the RPA C6 coefficients is estimated to be 13.2%.

关键词： Density functional approximations Density functional theory Density functional theory development Electron-correlation calculations Free-electron model

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The Semi-Markov model of operation and maintenance of gas analytical system 19

The Semi-Markov model of operation and maintenance of gas an...

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19th International Conference on Aviation and Cosmonautics, AviaSpace 2020

作者： Bobkov, V. Kanishchev, O. Men'Shova, I. Department of Higher Mathematics Branch of the National Research University Moscow Power Engineering Institute in Smolensk 1 Energeticheskiy Avenue Smolensk214013 Russia Department of Design SPA Analitpribor 3 Babushkina Street Smolensk214031 Russia Department of Logistics and Economic Informatics D Mendeleev University of Chemical Technology Russia Laboratory of Materials Science 9 Miusskaya Square Moscow125047 Russia

Gas analytical systems are one of the key elements for the safe operation of airports and ground airspace infrastructure facilities where there is a risk to life or property caused by the possible combustible gases leaks. The gas analytical systems provides safety operation of airspace infrastructure facilities through the early detection of combustible gases and the issuance of warning signal;therefor the gas analytical systems is imposed high operational reliability requirements ensured by an optimal maintenance strategy. Known methods of maintenance management could not consider operation features and gas analytical systems structure complexity therefore increase cost of maintenance of airspace infrastructure facilities. The developed semi-Markov model of operation and maintenance of gas analytical systems, which takes into account the frequency and duration of control, the intensity of operation, the reliability of components, quantity of the spare parts and the gas analytical systems complexity makes it possible to design optimal maintenance strategy and therefore to reduce the cost of maintenance of ground airspace infrastructure facilities by reducing insupportable wear out of gas analytical systems and to reduce capital expenditures by excluding an excessive amount of the spare parts. © Published under licence by IOP Publishing Ltd.

关键词： Gases

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Electronic correlations in the normal state of kagome superconductor KV3Sb5

arXiv

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arXiv 2021年

作者： Zhao, Jianzhou Wu, Weikang Wang, Yilin Yang, Shengyuan A. Co-Innovation Center for New Energetic Materials Southwest University of Science and Technology Mianyang621010 China Research Laboratory for Quantum Materials Singapore University of Technology and Design Singapore487372 Singapore Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore637371 Singapore Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of China HefeiAnhui230026 China

Recently, intensive studies have revealed fascinating physics, such as charge density wave and superconducting states, in the newly synthesized kagome-lattice materials AV3Sb5 (A=K, Rb, Cs). Despite the rapid progress, fundamental aspects like the magnetic properties and electronic correlations in these materials have not been clearly understood yet. Here, based on the density functional theory plus the single-site dynamical mean-field theory calculations, we investigate the correlated electronic structure and the magnetic properties of the KV3Sb5 family materials in the normal state. We show that these materials are good metals with weak local correlations. The obtained Pauli-like paramagnetism and the absence of local moments are consistent with recent experiment. We reveal that the band crossings around the Fermi level form three groups of nodal lines protected by the spacetime inversion symmetry, each carrying a quantized π Berry phase. Our result suggests that the local correlation strength in these materials appears to be too weak to generate unconventional superconductivity, and non-local electronic correlation might be crucial in this kagome system. © 2021, CC BY-NC-SA.

关键词： Magnetic properties

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Discovery of a metallic oxide with ultralow thermal conductivity

arXiv

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arXiv 2022年

作者： Dai, Jianhong Liu, Zhehong Ji, Jialin Dong, Xuejuan Yu, Jihai Ye, Xubin Wang, Weipeng Yu, RiCheng Hu, Zhiwei Zhao, Huaizhou Wan, Xiangang Zhang, Wenqing Long, Youwen Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China School of Physics University of Chinese Academy of Sciences Beijing100049 China Materials Genome Institute Shanghai University Shanghai200444 China Department of Physics Nanjing University Nanjing210093 China Max Planck Institute for Chemical Physics of Solids NöthnitzerStraße 40 Dresden01187 Germany Department of Materials Science and Engineering Shenzhen Institute for Quantum Science & Technology Southern University of Science and Technology Guangdong Shenzhen518055 China Shenzhen Municipal Key Lab for Advanced Quantum Materials and Devices Guangdong Provincial Key Lab for Computational Science and Materials Design Southern University of Science and Technology Guangdong Shenzhen518055 China Songshan Lake Materials Laboratory Guangdong Dongguan523808 China

A compound with metallic electrical conductivity usually has a considerable total thermal conductivity because both electrons and photons contribute to thermal transport. Here, we show an exceptional example of iridium oxide, Bi3Ir3O11, that concurrently displays metallic electrical conductivity and ultralow thermal conductivity approaching 0.61 W m-1 K-1 at 300 K. The compound crystallizes into a cubic structural framework with space group Pn-3. The edge- and corner-sharing IrO6 octahedra with a mixed Ir4.33+ charge state favor metallic electrical transport. Bi3Ir3O11 exhibits an extremely low lattice thermal conductivity close to the minimum limit in theory owing to its tunnel-like structure with filled heavy atoms Bi rattling inside. Theoretical calculations reveal the underlying mechanisms for the extraordinary compatibility between metallic electrical conductivity and ultralow thermal conductivity. This study may establish a new avenue for designing and developing unprecedented heat-insulation metals. Copyright © 2022, The Authors. All rights reserved.

关键词： Iridium compounds

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Cataloguing MoSi2N4and WSi2N4van der Waals Heterostructures: An Exceptional Material Platform for Excitonic Solar Cell Applications

arXiv

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arXiv 2022年

作者： Tho, Che Chen Yu, Chenjiang Tang, Qing Wang, Qianqian Su, Tong Feng, Zhuoer Wu, Qingyun Nguyen, C.V. Ong, Wee-Liat Liang, Shi-Jun Guo, San-Dong Cao, Liemao Zhang, Shengli Yang, Shengyuan A. Ang, Lay Kee Wang, Guangzhao Ang, Yee Sin Science Mathematics and Technology Cluster Singapore University of Technology and Design 487372 Singapore School of Electronic Information Engineering Key Laboratory of Extraordinary Bond Engineering and Advanced Materials Technology of Chongqing Yangtze Normal University Chongqing408100 China Department of Materials Science and Engineering Le Quy Don Technical University Hanoi100000 Viet Nam ZJU-UIUC Institute College of Energy Engineering Zhejiang University Haining Zhejiang Jiaxing314400 China State Key Laboratory of Clean Energy Utilization Zhejiang University Zhejiang Hangzhou310027 China Institute of Brain-Inspired Intelligence National Laboratory of Solid State Microstructures School of Physics Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing210093 China School of Electronic Engineering Xi'an University of Posts and Telecommunications Xi’an710121 China College of Physics and Electronic Engineering Hengyang Normal University Hengyang421002 China MIIT Key Laboratory of Advanced Display Materials and Devices School of Materials Science and Engineering Nanjing University of Science and Technology Nanjing210094 China

Two-dimensional (2D) materials van der Waals heterostructures (vdWHs) provides a revolutionary route towards high-performance solar energy conversion devices beyond the conventional silicon-based pn junction solar cells. Despite tremendous research progress accomplished in recent years, the searches of vdWHs with exceptional excitonic solar cell conversion efficiency and optical properties remain an open theoretical and experimental quest. Here we show that the vdWH family composed of MoSi2N4and WSi2N4monolayers provides a compelling material platform for developing high-performance ultrathin excitonic solar cells and photonics devices. Using first-principle calculations, we construct and classify 51 types of MoSi2N4and WSi2N4-based [(Mo,W)Si2N4] vdWHs composed of various metallic, semimetallic, semiconducting, insulating and topological 2D materials. Intriguingly, MoSi2N4/(InSe, WSe2) are identified as Type-II vdWHs with exceptional excitonic solar cell power conversion efficiency reaching well over 20%, which are competitive to state-of-art silicon solar cells. The (Mo,W)Si2N4vdWH family exhibits strong optical absorption in both the visible and ultraviolet regimes. Exceedingly large peak ultraviolet absorptions over 40%, approaching the maximum absorption limit of a free-standing 2D material, can be achieved in (Mo,W)Si2N4/α2-(Mo,W)Ge2P4vdWHs. Our findings unravel the enormous potential of (Mo,W)Si2N4vdWHs in designing ultimately compact excitonic solar cell device technology. Copyright © 2022, The Authors. All rights reserved.

关键词： Density functional theory

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A high-sensitivity frequency counter for free-induction-decay signals

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IEEE Transactions on Instrumentation and Measurement 2025年 74卷

作者： Gong, Tong Shu, Ming-Rui He, Jiang Liu, Kai Li, Yi-Ren Hao, Xin-Jun Sheng, Dong Wang, Yu-Ming Feng, Yu-Kun University of Science and Technology of China Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes Department of Precision Machinery and Precision Instrumentation Hefei 230027 China China Ship Research and Design Center Wuhan 430000 China University of Science and Technology of China CAS Center for Excellence in Comparative Planetology CAS Key Laboratory of Geospace Environment School of Earth and Space Sciences Deep Space Exploration Laboratory Hefei 230026 China University of Science and Technology of China Department of Modern Physics Hefei 230026 China

Real-time frequency readout of time-dependentpulsed signals with a high sensitivity are key elements in manyapplications using atomic devices, such as FID atomic magne-tometers. In this paper, we propose a frequency measurementalgorithm based on the Hilbert transform and implement sucha scheme in a FPGA-based frequency counter. By testing pulsedexponential-decay oscillation signals in the frequency range of 10to 500 kHz, this frequency counter shows a frequency sensitivitybetter than 100 μHz/√Hz at 10 Hz, with an output rate of200 Hz. When the output rate is increased to 1000 Hz, thesensitivity remains better than 400 μHz/√Hz at 10 Hz. Theperformance on frequency sensitivity is comparable with resultsobtained by off-line nonlinear fitting processes. In addition, thisfrequency counter does not require the pre-knowledge of theanalytic expression of the input signals. The realization of such adevice paves the way for practical applications of highly-sensitiveFID atomic magnetometers. © 1963-2012 IEEE.

关键词： FID magnetometer Frequency counter High bandwidth High-sensitivity Hilbert transform

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Effect of processing and microstructural properties of chickpea-flours on in vitro digestion and appetite sensations

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Food Research International 2022年 157卷 111245页

作者： Pälchen, Katharina Bredie, Wender L.P. Duijsens, Dorine Isaac Alfie Castillo, Alan Hendrickx, Marc Van Loey, Ann Raben, Anne Grauwet, Tara Laboratory of Food Technology Kasteelpark Arenberg 22 PB 2457 Leuven3001 Belgium Department of Food Science Section for Food Design and Consumer Behaviour Faculty of Science University of Copenhagen Rolighedsvej 26 FrederiksbergDK-1958 Denmark Department of Nutrition Exercise and Sports Faculty of Science University of Copenhagen Rolighedsvej 30 FrederiksbergDK-1958 Denmark Clinical Research Copenhagen University Hospital - Steno Diabetes Center Copenhagen HerlevDK-2730 Denmark

Nowadays, pulse flours are ingredients that are more and more used as substitutes in traditional staples (i.e., pasta, bread). In this study, cellular chickpea-flour was used as an ingredient to replace conventional raw-milled chickpea-flour in suspensions and semi-solid purees. The contribution of cellular integrity on in vitro macronutrient digestion and the subsequent effect on in vivo appetite sensations were investigated. Alternating the flour preparation sequence by interchanging hydrothermal treatment and mechanical disintegration (thermo-mechanical treatment) resulted in three chickpea-flours with distinct levels of cellular integrity, and thus nutrient accessibility. The study showed that cellular integrity in chickpea-flours was preserved upon secondary hydrothermal treatment and led to significant attenuation of in vitro macronutrient digestion as compared to conventional chickpea-flour. In a randomized crossover design, significant increase of mean in vivo subjective appetite sensations satiety and fullness along with decreases in hunger, desire to eat, and prospective food consumption were achieved when cellular integrity was kept without an effect on palatability and appearance of the purees (n = 22). In vitro digestion along with microstructural assessment confirmed the importance of cellular integrity for attenuating macronutrient digestion and thereby contributing to enhanced subjective satiety and fullness in pulses. Overall, this study highlights the promising potential of altarenating the flour preparation sequence resulting in macronutrient and energy-matched flours with different nutrient encapsulation which lead to different in vitro digestion kinetics and in vivo appetite sensations. © 2022 Elsevier Ltd

关键词： Disintegration

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Characterization of load-bearing and failure properties of fractured rock masses reinforced by negative pressure grouting

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Journal of Rock Mechanics and Geotechnical Engineering 2025年

作者： Fang, Juejing Yang, Ke Aslani, Farhad Lyu, Xin He, Xiang Li, Guiquan Zhang, Jiqiang Key Laboratory of Provincial and Ministry of Education for Safe and Efficient Mining of Coal Mines Anhui University of Science and Technology Huainan 232001 China Materials and Structures Innovation Group School of Engineering The University of Western Australia Perth 6009 WA Australia School of Engineering Edith Cowan University Perth 6027 WA Australia Hefei Design and Research Institute of Coal Industry Co. Ltd. Hefei 340041 China

Grouting injection is a vital technique for addressing the challenges of high stress and significant deformation in the surrounding rock during deep mining operations, playing a crucial role in promoting green and low-carbon extraction methodologies. In this study, grouting reinforcement processes were examined by conducting grouting experiments on a fractured rock with varying negative pressures (0–100 kPa), followed by uniaxial compression testing of the grout-reinforced bodies. This investigation explored the diffusion patterns of grout under negative pressure and established a constitutive model of damage-bearing capacity for bodies reinforced by negative pressure grouting. It further studied the enhancement effect of negative pressure on the load-bearing capacity of the reinforced bodies and analyzed the instability mechanism of damage and failure in these bodies. The results indicated that the diffusion of grout under negative pressure is influenced by four types of forces, which alter the extent of grout diffusion within the fractured rock mass. Introducing a damage constitutive model that serially connects pore and framework elements characterizes the damage and failure behavior of grout-reinforced bodies under different negative pressures. As the negative pressure increases, changes in porosity, water-to-cement ratio, and admixture quantity occur in the grout-reinforced specimens, with the strength mean curve showing a trend of first increasing and then decreasing, reaching a threshold at a negative pressure of 60 kPa. With increasing negative pressure, the negative pressure damage variable decreases and then increases, and the stronger the interfacial microelement connections caused by the negative pressure, the greater the bearing capacity, ultimately manifesting in different failure modes. © 2025 Institute of Rock and Soil Mechanics, Chinese Academy of sciences

关键词： Constitutive model Grout reinforcement Mechanical properties

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Active learning with multifidelity modeling for efficient rare event simulation

arXiv

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arXiv 2021年

作者： Dhulipala, Somayajulu L.N. Shields, Michael D. Spencer, Benjamin W. Bolisetti, Chandrakanth Slaughter, Andrew E. Labouré, Vincent M. Chakroborty, Promit Computational Mechanics and Materials Idaho National Laboratory Idaho FallsID83402 United States Department of Civil and Systems Engineering Johns Hopkins University BaltimoreMD21218 United States Advanced Reactor Technology and Design Idaho National Laboratory Idaho FallsID83402 United States Computational Frameworks Idaho National Laboratory Idaho FallsID83402 United States Reactor Physics Methods and Analysis Idaho National Laboratory Idaho FallsID83402 United States

While multifidelity modeling provides a cost-effective way to conduct uncertainty quantification with computationally expensive models, much greater efficiency can be achieved by adaptively deciding the number of required high-fidelity (HF) simulations, depending on the type and complexity of the problem and the desired accuracy in the results. We propose a framework for active learning with multifidelity modeling emphasizing the efficient estimation of rare events. Our framework works by fusing a low-fidelity (LF) prediction with an HF-inferred correction, filtering the corrected LF prediction to decide whether to call the high-fidelity model, and for enhanced subsequent accuracy, adapting the correction for the LF prediction after every HF model call. The framework does not make any assumptions as to the LF model type or its correlations with the HF model. In addition, for improved robustness when estimating smaller failure probabilities, we propose using dynamic active learning functions that decide when to call the HF model. We demonstrate our framework using several academic case studies and two finite element (FE) model case studies: estimating Navier-Stokes velocities using the Stokes approximation and estimating stresses in a transversely isotropic model subjected to displacements via a coarsely meshed isotropic model. Across these case studies, not only did the proposed framework estimate the failure probabilities accurately, but compared with either Monte Carlo or a standard variance reduction method, it also required only a small fraction of the calls to the HF model. © 2021, CC BY-NC-ND.

关键词： Uncertainty analysis

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An Investigation on Reaction Regularity of Mn-Fe-Ceox Catalyst System: Guide the Synthesis of Low-Temperature Nh3-Scr Catalytic Filter

SSRN

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SSRN 2024年

作者： Zhang, Yanbing Wang, Xie Liang, Banglei Ren, Haibo Zhang, Xiaoxia Liu, Xingye Zhang, Xiang Liu, Xuelian Song, Yang Zheng, Weijie Zhang, Huazhi College of Materials and Chemical Engineering Henan University of Urban Construction Pingdingshan467000 China College of Advanced Manufacturing Fuzhou University Jinjiang362251 China School of Chemistry and Chemical Engineering Anqing Normal University Anqing246011 China College of Environmental Science and Engineering North China Electric Power University Beijing102206 China Key Laboratory of Fine Chemical Application Technology of Luzhou Luzhou646099 China CAS Key Laboratory of Design and Assembly of Functional Nanostructures Fujian Provincial Key Laboratory of Nanomaterials State Key Laboratory of Structural Chemistry Fujian Institute of Research the Structure of Matter Chinese Academy of Sciences Fujian Fuzhou350002 China Luzhou Vocational and Technical College China

A series of catalytic filters (Mn-Fe-CeOx/PPS) with satisfied NO conversion and physical properties were synthesized by the redox method. The Mn-Fe-Ce ternary catalyst system and corresponding oxidation-reduction equation were established by using the low-valent oxidation characteristics of cerium and iron to react with the high-valent reduction manganese. Furthermore, the optimal catalytic filter synthesized under the guidance of reaction regularity has excellent physicochemical properties such as high NO conversion (100% at 180 oC), high stability, low loading capacity (66.8 g/m2), and strong binding ability, making it suitable for complex operating conditions. Particularly, in the Mn-Fe-Ce ternary catalyst system, the coexistence of Ce4+ and Ce3+ causes surface oxygen vacancies, uneven local charge distribution and additional chemisorbed oxygen, which are conducive to the low-temperature selective catalytic reduction (L-T SCR) reaction. Meanwhile, there are also high valence Mn4+ and Fe3+ in catalyst system, which can promote the oxidation of NO and further improve the L-T SCR reaction. © 2024, The Authors. All rights reserved.

关键词： Physicochemical properties

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