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arXiv 2019年

作者： Yang, Gang Ping, Jialun Ortega, Pablo G. Segovia, Jorge Department of Physics State Key Laboratory of Low-Dimensional Quantum Physics Tsinghua University Beijing100084 China Department of Physics Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University NanjingP. R.210023 China Universidad de Salamanca SalamancaE-37008 Spain Departamento de Sistemas Físicos Químicos y Naturales Universidad Pablo de Olavide SevillaE-41013 Spain

A constituent quark model, which has recently been successfully applied to the study of heavy quarkonium properties such as its spectrum but also a diverse array of observables related with their electromagnetic, strong and weak decays and reactions, is used herein to compute ground- and excited-state masses of QQQ-baryons containing either c- or b-quarks. Considering the lack of experimental information about the spectra of triply-heavy baryons, we believe that our computation could help on finding new states, since it is expected that phenomenological quark models describe triply-heavy baryons to a similar degree of accuracy as heavy quarkonia. The quark model parameters previously used to describe cc¯ and b¯b properties have not been modified for this analysis. The non-relativistic three-body bound-state problem is solved by means of the Gaußian expansion method which provides enough accuracy and simplifies the subsequent evaluation of the matrix elements. Several low-lying states with quantum numbers (formula presented) are reported. We compare our results with those predicted by many other theoretical formalisms. There is a general trend of agreement about the mass of the ground state in each sector of triply-heavy baryons;however, the situation is more puzzling for the excited states and thus appropriate comments on the most relevant features of our comparison are given. Copyright © 2019, The Authors. All rights reserved.

关键词： Hadrons

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B(s) → ηc(P, V) decays and effects of the next-to-leading order contributions in the perturbative QCD approach

arXiv

引用

arXiv 2019年

作者： Xiao, Zhen-Jun Yan, Da-Cheng Liu, Xin Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023 China School of Mathematics and Physics Changzhou University Changzhou213164 China Department of Physics Jiangsu Normal University Xuzhou221116 China

By employing the perturbative QCD (PQCD) factorization approach, we studied the sixteen B/Bs → ηc(π, K, η(′), ρ, K∗, ω, φ) decays with the inclusion of the currently known next-to-leading order (NLO) contributions. We found the following main points: (a) for the five measured B → ηc(K, K∗) and Bs → ηcφ decays, the NLO contributions can provide (80 − 180)% enhancements to the leading order (LO) PQCD predictions of their branching ratios, which play an important role to help us to interpret the data;(b) for the seven ratios R1,···,7 of the branching ratios defined among the properly selected pair of the considered decay modes, the PQCD predictions for the values of R3,4,5 agree well with those currently available BaBar and Belle measurements;(c) for B0 → ηcKS0 decay, the PQCD predictions for both the direct and mixing induced CP asymmetries do agree very well with the measured values within errors;and (d) the PQCD predictions for ratios R1,2 and R6,7 also agree with the general expectations and will be tested by the future experiments. Copyright © 2019, The Authors. All rights reserved.

关键词： Forecasting

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The ■ (q=u, d;Q=c, b) tetraquark system in a chiral quark model

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Chinese Physics C 2024年第7期 88-109页

作者：杨刚平加伦 Jorge Segovia Department of Physics Zhejiang Normal University Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Departamento de Sistemas Físicos Químicos y NaturalesUniversidad Pablo de Olavide

The S-wave ■（q=u,d;Q=c,b） tetraquarks,with spin-parities JP=0+,1+,and 2+,in both isoscalar and isovector sectors,are systematically studied using a chiral quark *** meson-meson,diquark-antidiquark,and K-type arrangements of quarks and all possible color wave functions are comprehensively *** four-body system is solved using the Gaussian expansion method,a highly efficient computational ***,a complex-scaling formulation of the problem is established to disentangle bound,resonance,and scattering *** theoretical framework has already been successfully applied in various tetra-and penta-quark *** the complete coupled channel and within the complex-range formulation,several narrow resonances of ■ systems are obtained,in each allowed I（JP）-channel,within the energy regions of 2.4-3.4 GeV and 5.7-6.7 GeV,*** predicted exotic states,which indicate a richer color structure when going towards multiquark systems beyond mesons and baryons,are expected to be confirmed in future high-energy particle and nuclear experiments.

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Numerical Study of Performance of T-Micromixer with Helical Elements for the Energetic Application of Microfluidics

SSRN

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SSRN 2023年

作者： Mahammedi, Abdelkader Tayeb, Naas Toufik Rahmani, Kouider Al-Kassir, Awf Cuerda-Correa, Eduardo Manuel Department of Technology Ziane Achour University of Djelfa Djelfa17000 Algeria Gas Turbine Joint Research Team University of Djelfa Djelfa17000 Algeria Research Laboratory Modeling Simulation and Optimization of Real Complex Systems Djelfa17000 Algeria Departamento de Química Orgánica e Inorgánica Facultad de Ciencias Universidad de Extremadura Avenida de Elvas s/n Badajoz06006 Spain

Mixing index, pressure drop, and kinematic measurements within the T-micromixer with helical elements and their related mixing performances have been studied and validated using CFD, for different values of Reynolds number (0.1 - 60) for laminar Newtonian miscible fluid. Geometrical characteristics were further examined to improve the mixing performance. Various values of twisted angles were evaluated and compared to choose the optimal angle. Two new parameters, Q and λ, were introduced to represent the ratio of vorticity square over the sum of vorticity square and deformation square intensities. Furthermore, the results of the numerical simulation were compared with the given data in the literature, showing a significant agreement, in addition to the fact that a high-quality mixture can be created with a geometry angle of 90°, and a mixing index above 0.99 can be obtained at low Reynolds numbers. The numerical investigation of the flow regimes of miscible fluid in the T-microkenics with the proposed angle can be utilized to develop the mixing performance of the micromixers in a wide variety of processes. © 2023, The Authors. All rights reserved.

关键词： Vorticity

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First principles investigations of the electronic and magnetic properties of RVO3 (R = Er, Ho, Y, Lu) vanadates

arXiv

引用

arXiv 2022年

作者： Jmal, Sohail Ait Balli, Sohail Ait Bouhani, Hamza Mounkachi, Omar AMEEC Team LERMA International University of Rabat Parc Technopolis Rocade de Rabat- Salé 11100 Morocco Complex Systems and Interactions Ecole Centrale Casablanca Morocco Laboratory of Condensed Matter and Interdisciplinary Sciences Department of Physics Faculty of Sciences Mohammed V University in Rabat PO Box 1014 Rabat Morocco Modeling Simulation & Data Analysis Program Mohammed VI Polytechnic University Ben Guerir43150 Morocco

In this paper, we investigate the influence of the rare earth element (R) on the physical properties of RVO3 (R = Er, Ho, Y, Lu). For this purpose, a theoretical work is reported in this study using ab initio method with the intent of enhancing our knowledge of the electronic, and magnetic properties of RVO3 (R = Er, Ho, Y, Lu) compounds. The electronic properties of these materials show the presence of Jahn-Teller effect, with a band gap of approximately 0.58eV, 1.57eV, 1.12eV, 1.28eV, for ErVO3, HoVO3, YVO3, LuVO3, respectively. The magnetic contribution of Ho, Er, and V atoms in HoVO3, and ErVO3 compounds was disentangled using X-ray magnetic circular dichroism (XMCD). The magnetic anisotropies of RVO3 with (R = Er, Ho, Y, Lu) are studied and analyzed using spin orbit coupling. We noticed an easy axis of magnetization along the c-direction with strong magneto-crystalline anisotropy energies for the non-magnetic rare earth elements (R = Lu, Y)VO3. For the magnetic rare earth elements, the easy and hard magnetization direction were found to be along b-axis and c-axis, and a- axis and c-axis for HoVO3, and ErVO3, respectively. This means that instead of the standard magnetization demagnetization process, large thermal effects can be obtained by spinning their single crystals in constant magnetic fields. The exchange coupling between (Ho-V) is also found to be greater than the other exchange interactions in HoVO3. Accordingly, a large conventional magnetocaloric effect could be created in HoVO3, since the Ho Ising moments experience a metamagnetic transition. However, the magnetocaloric effect (MCE) is expected to be lower in ErVO3 due to the weak (Er-V) exchange coupling. © 2022, CC BY.

关键词： Holmium compounds

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Visualization of signalized intersections in driving simulator and validity of driving behaviors in virtual environments

Advances in Transportation Studies

引用

Advances in Transportation Studies 2011年第26期 17-28页

作者： Yan, X. Abdel-Aty, M. Guo, D. Radwan, E. MOE Key Laboratory for Transportation Complex Systems Theory and Technology Beijing Jiaotong University Beijing 100044 China Department of Civil and Environmental Engineering University of Central Florida Orlando FL 32816-2450 United States Computer Science Program College of Business Florida Gulf Coast University 10501 FGCU Boulevard South Fort Myers FL 33965-6565 United States Center for Advanced Transportation Systems Simulation University of Central Florida Orlando FL 32816-2450 United States

Visualization of highway traffic environments in virtual reality plays a key role on fidelity of simulation and validity of driving behaviors in driving simulator studies. This paper describes a procedure to replicate a signalized intersection with many complex features into a driving simulator's 3-D databases through building a graphical visual database, constructing a road motion database, and creating simulated traffic. The validity of the visualization was assessed via the comparison of the drivers' speeds in the simulator and the speed data at the real intersection. It was found that both speed data follow normal distributions and have equal means for each intersection approach;however, that the speeds measured in the driving simulator have a larger variability than those measured in the field. The users' subjective evaluation results indicated that 92% subjects could recognize the simulated intersection in the driving simulator experiment. Therefore, the strategy of geo-specific environment modeling would be useful for studying driving behaviors in virtual environments.

关键词： Visualization

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Doubly charmed pentaquarks

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Physical Review D 2020年第7期101卷 074030-074030页

作者： Gang Yang Jialun Ping Jorge Segovia Department of Physics Zhejiang Normal University Jinhua 321004 China Department of Physics Tsinghua University Beijing 100084 China Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People’s Republic of China Departamento de Sistemas Físicos Químicos y Naturales Universidad Pablo de Olavide E-41013 Sevilla Spain

The LHCb collaboration, using its full data set from runs 1 and 2, announced in 2019 a surprising update of the hidden-charm pentaquark states Pc(4380)+ and Pc(4450)+, observed in 2015. A new state, Pc(4312)+, was clearly seen at lower energies; furthermore, the original Pc(4450) resonance was resolved into two individual states, named the Pc(4440)+ and the Pc(4457)+. Motivated by the fact that these new hidden-charm pentaquark states were successfully predicted by our chiral quark model, we extend herein such study to the doubly charmed sector. The analyzed total spin and parity quantum numbers are JP=12−, 32− and 52−, in the I=12 and 32 isospin channels. We find several possible narrow baryon-meson resonances (theoretical masses in parenthesis): IJP=1212− ΣcD(4356), 1232− Σc*D(4449), 3212− ΣcD(4431), 3212− ΣcD(4446), 3232− ΣcD*(4514) and 3252− Ξcc*ρ(4461) whose widths are 4.8, 8.0, 2.6, 2.2, 4.0 and 3.0 MeV, respectively. Moreover, one shallow bound state is found, too, with quantum numbers IJP=1232− Ξcc*π(3757). These doubly charmed pentaquark states are expected to be identified in future experiments.

关键词： Quark model Strong interaction

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An integrated framework for accelerating reactive flow simulation using GPU and machine learning models

arXiv

引用

arXiv 2023年

作者： Mao, Runze Wang, Yingrui Zhang, Min Li, Han Xu, Jiayang Dong, Xinyu Zhang, Yan Chen, Zhi X. State Key Laboratory of Turbulence and Complex Systems Aeronautics and Astronautics College of Engineering Peking University Beijing100871 China Beijing100080 China Shanghai SenseTime Intelligent Technology Co. LTD Shanghai200233 China CAEP Software Center for High Performance Numerical Simulation Beijing100088 China Institute of Applied Physics and Computational Mathematics Beijing100088 China

Recent progress in artificial intelligence (AI) and high-performance computing (HPC) have brought potentially game-changing opportunities in accelerating reactive flow simulations. In this study, we introduce an open-source computational fluid dynamics (CFD) framework that integrates the strengths of machine learning (ML) and graphics processing unit (GPU) to demonstrate their combined capability. Within this framework, all computational operations are solely executed on GPU, including ML-accelerated chemistry integration, fully-implicit solving of PDEs, and computation of thermal and transport properties, thereby eliminating the CPU-GPU memory copy overhead. Optimisations both within the kernel functions and during the kernel launch process are conducted to enhance computational performance. Strategies such as static data reorganisation and dynamic data allocation are adopted to reduce the GPU memory footprint. The computational performance is evaluated in two turbulent flame benchmarks using quasi-DNS and LES modelling, respectively. Remarkably, while maintaining a similar level of accuracy to the conventional CPU/CVODE-based solver, the GPU/ML-accelerated approach shows an overall speedup of over two orders of magnitude for both cases. This result highlights that high-fidelity turbulent combustion simulation with finite-rate chemistry that requires normally hundreds of CPUs can now be performed on portable devices such as laptops with a medium-end GPU. © 2023, CC BY.

关键词： Graphics processing unit

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Dynamical relaxation behavior of an extended XY chain with a gapless phase following a quantum quench

引用

Physical Review B 2024年第2期109卷 024303-024303页

作者： Kaiyuan Cao Yayun Hu Peiqing Tong Guangwen Yang Zhejiang Lab Hangzhou 311100 People's Republic of China Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing 210023 People's Republic of China and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People's Republic of China Zhejiang Lab Hangzhou 311100 People's Republic of China and Department of Computer Science and Technology Tsinghua University Haidian District Beijing 100084 People's Republic of China

We investigate the dynamical relaxation behavior of the two-point correlation in extended XY models with a gapless phase after quenches from various initial states. Specifically, we study the XY chain with gapless phase induced by the following additional interactions: Dzyaloshinskii-Moriya interaction and the XZY-YZX type of three-site interaction. When quenching from the gapped phase, we observe that the additional interactions have no effect on the relaxation behavior. The relaxation behavior is δCmn(t)∼t−3/2 and ∼t−1/2 for the quench to the commensurate phase and the incommensurate phase, respectively. However, when quenching from the gapless phase, we demonstrate that the scaling behavior of δCmn(t) is changed to ∼t−1 for the quench to the commensurate phase, and the decay of δCmn(t) follows ∼t−1 or ∼t−1/2 for the quench to the incommensurate phase depending on the parameters of prequench Hamiltonian. We also establish the dynamical phase diagrams based on the dynamical relaxation behavior of δCmn(t) in the extended XY models.

关键词： Dynamical phase transitions Dzyaloshinskii-Moriya interaction Quantum quench XY model

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Non-Rigid Metal–Oxygen Bonding Empowered Nitrate Reduction on Ruthenium Catalysts

SSRN

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SSRN 2024年

作者： Wang, Suwen Zhuang, Zechao Xu, Jiawei Fu, Cheng Qiu, Zhen Feng, Huajun Xiang, Hai Chen, Zuliang Li, Hui Zhang, Lei Li, Yongfu Cai, Yanjiang Ma, Tianyi Yu, Bing State Key Laboratory of Subtropical Silviculture Zhejiang A&F University Hangzhou311300 China Zhejiang A&F University Hangzhou311300 China Department of Chemistry Tsinghua University Beijing100084 China Jiangsu Key Laboratory of Numerical Simulation of Large Scale Complex Systems School of Chemistry and Materials Science Nanjing Normal University Nanjing210023 China Fujian Key Laboratory of Pollution Control and Resource Reuse School of Environmental and Resource Sciences Fujian Normal University Fujian Province Fuzhou350007 China School of Science RMIT University MelbourneVIC3000 Australia Centre for Translational Atomaterials

Electrocatalytic nitrate reduction (NitRR) offers exciting potential for mass production of ammonia (NH3) from renewables. However, the rigidity of metal−ligand bonds in most electrocatalysts renders them unable to survive the structural transformations required for NitRR. Herein, we establish a type of non-rigid metal−oxygen bonds by employing graphene oxide (GO) sheets as a 'micron-scale' ligand for transition metals (TM). Because of being confined to the interfaces between GO and TM, the oxygenated groups in GO can associate with and dissociate from the TM in response to reaction dynamics. As a proof-of-concept demonstration, an electrocatalyst was developed by dispersing nanoscale ruthenium (Ru) on graphene oxide (GO) and utilizing two-dimensional MXene to compensate for the low electrical conductivity of GO. This electrocatalyst exhibits a maximum NH3 yield of over 5 mg cm−2 h−1, with almost 100% current-to-NH3 efficiency, far outperforming the performance of most reported Ru-based materials. What's even more remarkable is the achievement of a record-breaking performance: a 200-hour stable electrolysis with a NH3 yield of 40.2 mg cm−2 h−1, using a membrane electrode reactor. Our experimental and theoretical investigations further reveal the non-rigidity of the Ru–O bonds and how they self-regulate to adapt to diverse intermediates involved in NitRR. This work provides an approach to fabricate a high-performance electrocatalyst featuring reversible and non-rigid metal−oxygen bonds, opening new possibilities for practical nitrate electrolysis. © 2024, The Authors. All rights reserved.

关键词： Electrocatalysis

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