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Atomic origin of minor alloying element effect on glass forming ability of metallic glass

Chinese Physics B 2025年第3期34卷 483-489页

作者： Shan Zhang Qingan Li Yong Yang Pengfei Guan Beijing Computational Science Research Center Beijing 100193China Department of Mechanical Engineering College of EngineeringCity University of Hong KongTat Chee AvenueKowloon TongKowloonHong KongChina Advanced Interdisciplinary Sciences Research(AiR)Center Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China

The glass-forming ability(GFA)of metallic glasses is a key scientific challenge in their development and application,with compositional dependence playing a crucial *** studies have demonstrated that the addition of specific minor elements can greatly enhance the GFA of parent alloys,yet the underlying mechanism remains *** this study,we use the ZrCuAl system as a model to explore how the addition of minor Al influences the crystallization rate by modulating the properties of the crystal-liquid interface,thereby affecting the *** results reveal that the minor addition of Al significantly reduces the crystal growth rate,a phenomenon not governed by particle density fluctuations at the *** impact of minor element additions extends beyond a modest increase in crystal-unfavorable motifs in the bulk supercooled *** importantly,it leads to a significant enrichment of these motifs at the crystal-supercooled liquid interface,forming a dense topological network of crystal-unfavorable structures that effectively prevent the growth of the crystalline interface and enhance *** results provide valuable insights for the design and development of high-performance metallic glasses.

关键词： metallic glass glass forming ability interface structure molecular dynamics(MD)

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A DEEP LEARNING BASED DISCONTINUOUS GALERKIN METHOD FOR HYPERBOLIC EQUATIONS WITH DISCONTINUOUS SOLUTIONS AND RANDOM UNCERTAINTIES

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Journal of computational Mathematics 2023年第6期41卷 1281-1304页

作者： Jingrun Chen Shi Jin Liyao Lyu School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China Suzhou Institute for Advanced Research University of Science and Technology of ChinaSuzhou 215123China School of Mathematical Sciences Institute of Natural Sciencesand MOE-LSCShanghai Jiao Tong UniversityShanghai200240China Department of Computational Mathematics Scienceand EngineeringMichigan State UniversityEast LansingMI48824USA

We propose a deep learning based discontinuous Galerkin method(D2GM)to solve hyperbolic equations with discontinuous solutions and random *** main computational challenges for such problems include discontinuities of the solutions and the curse of dimensionality due to *** learning techniques have been favored for high-dimensional problems but face difficulties when the solution is not smooth,thus have so far been mainly used for viscous hyperbolic system that admits only smooth *** alleviate this difficulty by setting up the loss function using discrete shock capturing schemes–the discontinous Galerkin method as an example–since the solutions are smooth in the discrete *** convergence of D2GM is established via the Lax equivalence theorem kind of *** high-dimensional random space is handled by the Monte-Carlo *** a setup makes the D2GM approximate high-dimensional functions over the random space with satisfactory accuracy at reasonable *** D2GM is found numerically to be first-order and second-order accurate for(stochastic)linear conservation law with smooth solutions using piecewise constant and piecewise linear basis functions,*** examples are given to verify the efficiency and the robustness of D2GM with the dimensionality of random variables up to 200 for(stochastic)linear conservation law and(stochastic)Burgers’equation.

关键词： Discontinuous Galerkin method Loss function Convergence analysis Deep learning Hyperbolic equation

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Phase-coherence dynamics of frequency-comb emission via high-order harmonic generation in few-cycle pulse trains

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Chinese Physics B 2023年第3期32卷 205-211页

作者：梁畅通张晶晶李鹏程 Research Center for Advanced Optics and Photoelectronics Department of PhysicsCollege of ScienceShantou UniversityShantou 515063China Key Laboratory of Intelligent Manufacturing Technology of the Ministry of Education Shantou UniversityShantou 515063China Institute of Applied Physics and Computational Mathematics Beijing 100088China

Frequency-comb emission via high-order harmonic generation(HHG)provides an alternative method for the coherent vacuum ultraviolet(VUV)and extreme ultraviolet(XUV)radiation at ultrahigh repetition *** particular,the temporal and spectral features of the HHG were shown to carry profound insight into frequency-comb emission *** we present an ab initio investigation of the temporal and spectral coherence of the frequency comb emitted in HHG of He atom driven by few-cycle pulse *** find that the emission of frequency combs features a destructive and constructive coherences caused by the phase interference of HHG,leading to suppression and enhancement of frequency-comb *** results reveal intriguing and substantially different nonlinear optical response behaviors for frequency-comb emission via *** dynamical origin of frequency-comb emission is clarified by analyzing the phase coherence in HHG processes in *** results provide fresh insight into the experimental realization of selective enhancement of frequency comb in the VUV–XUV regimes.

关键词： high-order harmonic generation frequency comb time-dependent Schro¨dinger equation intense laser field systems

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IMPROVED ENGINE DATA ACQUISITION SYSTEM AND INTERFACE TO ENABLE EXPERIMENTATION WITH EMERGING ALTERNATIVE FUELS IN A SPARK-IGNITED CFR ENGINE

IMPROVED ENGINE DATA ACQUISITION SYSTEM AND INTERFACE TO ENA...

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ASME 2024 ICE Forward Conference, ICEF 2024

作者： Loprete, Jason Dimosthenous, Christos Assanis, Dimitris Stony Brook University Stony BrookNY United States Advanced Energy Research and Technology Center Stony BrookNY United States Institute for Advanced Computational Science Stony BrookNY United States

ISBN: (纸本)9780791888520

Existing engine facilities often build upon legacy hardware and assumptions that were once state-of-the-art, but have since become less relevant or even outdated in the face of new research challenges facing the community today. Often, assumptions and simplifications to experimentation or analysis, once necessary to be made due to the computational limitations of the hardware at the time of initial development, are carried forward. These legacy elements can potentially limit the effectiveness of accurately describing key parameters or metrics before, during or post experimentation. The behavior of novel fuels is also not always fully understood, which highlights the need for tools to guide the design of the experimental matrix to avoid unexpected and potentially dangerous outcomes. Determining these key and critical experimentation parameters places additional strain on researchers during both the dry-lab (pre-experimentation), experimentation, and data post-processing phases, which in turn reduces the overall efficiency of the experimental process. With these factors in mind, this manuscript details the conversion of an existing spark-ignited single-cylinder Cooperative Fuel Research (CFR) engine, typically in-service at industrial plants for fuel octane testing or reserved for educational and light-duty research tasks, to a test cell equipped to handle a variety of different emerging alternative fuels. Specifically, modifications to the in-house LabVIEW program and data acquisition system are detailed, with emphasis on providing additional tools to aid in the expediency and more importantly assist in the safety during experiments. This includes the conversion of the existing CFR testing facility from a single liquid or single gaseous fuel capable system to a multi-fuel compatible system, complete with on-the-fly calculations of mass, energy, and volume fractions of existing fuel blends, increased low-speed sampling rates, and a calculating tool to determine scalar

关键词： Digital storage

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Communication Optimization for Distributed GCN Training on ABCI Supercomputer

Communication Optimization for Distributed GCN Training on A...

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IEEE International Conference on Cluster Computing Workshops and Posters (CLUSTER WORKSHOPS)

作者： Chen Zhuang Peng Chen Xin Liu Toshio Endo Satoshi Matsuoka Mohamed Wahib Tokyo Institute of Technology National Institute of Advanced Industrial Science and Technology RIKEN Center for Computational Science

ISBN: (数字)9798350383454

ISBN: (纸本)9798350383461

Graph Convolutional Networks (GCNs) are widely used in various domains. However, training distributed full-batch GCNs on large-scale graphs poses challenges due to high communication overhead. This work presents a hybrid pre-post-aggregation approach and an integer quantization method to reduce communication costs. With these techniques, we develop a scalable distributed GCN training framework, SuperGNN, for supercomputers ABCI. Experimental results on multiple large graph datasets show that our method achieves a speedup of up to 6× compared with the state-of-the-art implementations, without sacrificing model accuracy.

关键词： Training Quantization (signal) Costs Accuracy Graph convolutional networks Conferences Cluster computing Supercomputers Optimization

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Superexchange Interactions and Magnetic Anisotropy in MnPSe_(3)Monolayer

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Chinese Physics Letters 2023年第7期40卷 56-62页

作者：王光宇杨柯马曜峥行刘禄芦地周宇轩吴骅 Laboratory for Computational Physical Sciences(MOE) State Key Laboratory of Surface Physicsand Department of PhysicsFudan UniversityShanghai 200433China Shanghai Qi Zhi Institute Shanghai 200232China College of Science University of Shanghai for Science and TechnologyShanghai 200093China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

Two-dimensional van der Waals magnetic materials are of great current interest for their promising applications in *** density functional theory calculations in combination with the maximally localized Wannier functions method and the magnetic anisotropy analyses,we study the electronic and magnetic properties of MnPSe_(3)*** results show that it is a charge transfer antiferromagnetic(AF)*** this Mn^(2)+3d^(5)system,although it seems straightforward to explain the AF ground state using the direct exchange,we find that the nearly 90oMn-Se-Mn charge transfer type superexchange plays a dominant role in stabilizing the AF ground ***,our results indicate that,although the shape anisotropy favors an out-of-plane spin orientation,the spin-orbit coupling(SOC)leads to the experimentally observed in-plane spin *** prove that the actual dominant contribution to the magnetic anisotropy comes from the second-order perturbation of the SOC,by analyzing its distribution over the reciprocal *** the AF exchange and anisotropy parameters obtained from our calculations,our Monte Carlo simulations give the Néel temperature T_(N)=47 K for MnPSe_(3)monolayer,which agrees with the experimental 40 ***,our calculations show that under a uniaxial tensile(compressive)strain,Néel vector would be parallel(perpendicular)to the strain direction,which well reproduces the recent *** also predict that T_(N)would be increased by a compressive strain.

关键词： anisotropy exchange magnetic

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Rational design of large anomalous Nernst effect in Dirac semimetals

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npj computational Materials 2023年第1期9卷 258-264页

作者： Panshuo Wang Zongxiang Hu Xiaosong Wu Qihang Liu Shenzhen Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology518055 ShenzhenChina State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Frontiers Science Center for Nano-optoelectronicsand Collaborative Innovation Center of Quantum MatterPeking University100871 BeijingChina Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology518055 ShenzhenChina Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and Technology518055 ShenzhenChina

Anomalous Nernst effect generates a transverse voltage perpendicular to the temperature *** has several advantages compared with the longitudinal thermoelectricity for energy conversion,such as decoupling of electronic and thermal transports,higher flexibility,and simpler lateral ***,a design principle beyond specific materials systems for obtaining a large anomalous Nernst conductivity(ANC)is still *** this work,we theoretically demonstrate that a pair of Dirac nodes under a Zeeman field manifests an odd-distributed,double-peak anomalous Hall conductivity curve with respect to the chemical potential and a compensated carrier feature,leading to an enhanced ANC compared with that of a simple Weyl semimetal with two Weyl *** on first-principles calculations,we then provide two Dirac semimetal candidates,i.e.,Na3Bi and NaTeAu,and show that under a Zeeman field,they exhibit a sizable ANC value of 0.4 Am^(-1)K^(-1) and 1.3 Am^(-1)K^(-1),respectively,near the Fermi *** an approach is also applicable to ferromagnetic materials with intrinsic Zeeman splitting,as exemplified by a hypothetical alloy NaFeTe2Au2,exhibiting an ANC as high as 3.7 Am^(-1)K^(-1) at the Fermi *** work provides a design principle with a prototype band structure for enhanced ANC pinning at the Fermi level,shedding light on the inverse design of other specific functional materials based on electronic structure.

关键词： structure Nernst Dirac

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Improving MPI Language Support Through Custom Datatype Serialization

Improving MPI Language Support Through Custom Datatype Seria...

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2024 Workshops of the International Conference for High Performance Computing, Networking, Storage and Analysis, SC Workshops 2024

作者： Tronge, Jake Schuchart, Joseph Dalcin, Lisandro Pritchard, Howard Los Alamos National Laboratory Los AlamosNM United States Institute for Advanced Computational Science Stony BrookNY United States King Abdullah University of Science and Technology Thuwal Saudi Arabia

ISBN: (纸本)9798350355543

Exascale applications are being increasingly written in modern languages such as Python, Julia, C++, and Rust. The Message-Passing Interface (MPI), the de facto standard for parallel computing, only defines interfaces for C and Fortran, languages that are very different from these modern languages, often containing more complex types and representations incompatible with MPI. The existing derived datatype interface is widely used for older applications, but fails to work efficiently for types containing multiple pointers, requiring application-specific initialization, or serialization. Applications written in these languages can still use MPI, but at the cost of complicated address manipulation or high overhead. This work proposes a new datatype interface for MPI giving more control to the application over buffer packing and the wire representation. We built a prototype for this interface, demonstrating it with Rust, Python, and C++, highlighting key concerns of each language and showing the improvements provided. © 2024 IEEE.

关键词： C++ Data serialization distributed datatypes Julia MPI Python Rust

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Investigating the Robustness of Modelling Decisions for Few-Shot Cross-Topic Stance Detection: A Preregistered Study 30

Investigating the Robustness of Modelling Decisions for Few-...

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Joint 30th International Conference on computational Linguistics and 14th International Conference on Language Resources and Evaluation, LREC-COLING 2024

作者： Reuver, Myrthe Verberne, Suzan Fokkens, Antske Computational Linguistics and Text Mining Lab Vrije Universiteit Amsterdam Netherlands Leiden Institute of Advanced Computer Science Leiden University Netherlands Dept. of Mathematics and Computer Science Eindhoven University of Technology Netherlands

ISBN: (纸本)9782493814104

For a viewpoint-diverse news recommender, identifying whether two news articles express the same viewpoint is essential. One way to determine"same or different" viewpoint is stance detection. In this paper, we investigate the robustness of operationalization choices for few-shot stance detection, with special attention to modelling stance across different topics. Our experiments test pre-registered hypotheses on stance detection. Specifically, we compare two stance task definitions (Pro/Con versus Same Side Stance), two LLM architectures (bi-encoding versus cross-encoding), and adding Natural Language Inference knowledge, with pre-trained RoBERTa models trained with shots of 100 examples from 7 different stance detection datasets. Some of our hypotheses and claims from earlier work can be confirmed, while others give more inconsistent results. The effect of the Same Side Stance definition on performance differs per dataset and is influenced by other modelling choices. We found no relationship between the number of training topics in the training shots and performance. In general, cross-encoding out-performs bi-encoding, and adding NLI training to our models gives considerable improvement, but these results are not consistent across all datasets. Our results indicate that it is essential to include multiple datasets and systematic modelling experiments when aiming to find robust modelling choices for the concept 'stance'. © 2024 ELRA Language Resource Association: CC BY-NC 4.0.

关键词： Encoding (symbols)

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sp^(2) to sp^(3) hybridization transformation in 2D metal-semiconductor contact interface suppresses tunneling barrier and Fermi level pinning simultaneously

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Nano Research 2024年第11期17卷 10227-10234页

作者： Wenchao Shan Anqi Shi Zhuorong Zhong Xiuyun Zhang Bing Wang Yongtao Li Xianghong Niu School of Science State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM) and College of Electronic and Optical Engineering Nanjing University of Posts and Telecommunications Nanjing 210023 China College of Physics Science and Technology Yangzhou University Yangzhou 225002 China Institute for Computational Materials Science Joint Center for Theoretical Physics (JCTP) School of Physics and Electronics Henan University Kaifeng 475004 China Key Laboratory of Quantum Materials and Devices (Southeast University) Ministry of Education Nanjing 211189 China

Van der Waals (vdWs) stacking of two-dimensional (2D) materials can effectively weaken the Fermi level pinning (FLP) effect in metal/semiconductor contacts due to dangling-bond-free surfaces. However, the inherent vdWs gap always induces a considerable tunneling barrier, significantly limiting carrier injection. Herein, by inducing a sp^(2) to sp^(3) hybridization transformation in 2D carbon-based metal via surface defect engineering, the large orbital overlap can form an efficient carrier channel, overcoming the tunneling barrier. Specifically, by selecting the 2D carbon-based X_(3)C_(2) (X = Cd, Hg, and Zn) metal and the 2D MSi_(2)N_(4) (M = Cr, Hf, Mo, Ti, V, and Zr) semiconductor, we constructed 36 metal/semiconductor contacts. For vdWs contacts, although Ohmic contacts can be formed at the interface, the highest tunneling probability (P TB) is only 3.11%. As expected, the P TB can be significantly improved, as high as 48.73%, when MSi_(2)N_(4), accompanied by surface nitrogen vacancies, forms an interface covalent bond with X_(3)C_(2). Simultaneously, weak FLP and Ohmic contact remain at the covalent-bond-based surface, attributing to the protection of the MSi_(2)N_(4) band-edge electronic states by the outlying Si-N sublayer. Our work provides a promising path for advancing the progress of 2D electronic and photoelectronic devices.

关键词： two-dimensional(2D)material metal-semiconductor contacts tunneling-barrier Schottky barrier density functional theory

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