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Local step-flow dynamics in thin film growth with desorption

Physical Review Materials 2024年第3期8卷 033403-033403页

作者： Xiaozhi Zhang Jeffrey G. Ulbrandt Peco Myint Andrei Fluerasu Lutz Wiegart Yugang Zhang Christie Nelson Karl F. Ludwig Randall L. Headrick Department of Physics and Materials Science Program University of Vermont Burlington Vermont 05405 USA Division of Materials Science and Engineering Boston University Boston Massachusetts 02215 USA X-ray Science Division Argonne National Laboratory Lemont Illinois 60439 USA National Synchrotron Light Source II Brookhaven National Lab Upton New York 11973 USA Department of Physics Boston University Boston Massachusetts 02215 USA

Desorption of deposited species plays a role in determining the evolution of surface morphology during crystal growth when the desorption time constant is short compared with the time to diffuse to a defect site, step edge, or kink. However, experiments to directly test the predictions of these effects are lacking. Novel techniques such as in situ coherent x-ray scattering can provide significant new information. Herein we present x-ray photon correlation spectroscopy (XPCS) measurements during diindenoperylene (DIP) vapor deposition on thermally oxidized silicon surfaces. DIP forms a nearly complete two-dimensional first layer over the range of temperatures studied (40–120∘C), followed by mounded growth during subsequent deposition. Local step flow within mounds was observed, and we find that there was a terrace-length-dependent behavior of the step edge dynamics. This led to unstable growth with rapid roughening (β>0.5) and deviation from a symmetric error-function-like height profile. At high temperatures, the grooves between the mounds tend to close up leading to nearly flat polycrystalline films. Numerical analysis based on a (1+1)-dimensional model suggests that terrace-length dependent desorption of deposited ad-molecules is an essential cause of the step dynamics, and it influences the morphology evolution.

关键词： Growth Surface diffusion Surface instabilities Atomic force microscopy Surface scattering X-ray techniques

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All-optical nonreciprocal response in a ring resonator integrating transition metal dichalcogenides

All-optical nonreciprocal response in a ring resonator integ...

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CLEO: Science and Innovations, S and I 2022

作者： Kawaguchi, Yuma Guddala, Sriram Komissarenko, Filipp Kiriushechkina, Svetlana Vakulenko, Anton Chen, Kai Alù, Andrea Menon, Vinod M. Khanikaev, Alexander B. Department of Electrical Engineering Grove School of Engineering City College of the City University of New York New YorkNY United States Physics Program Graduate Center of the City University of New York New YorkNY United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY United States Department of Physics City College of New York New YorkNY United States

The photoinduced nonreciprocity was experimentally observed in WS2 monolayer pumped by circularly polarized light. Based on this, we propose a theoretical model of nonreciprocal optical ring resonator integrating vall... 详细信息

ISBN: (纸本)9781557528209

关键词： Monolayers

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Dynamical evolution of critical fluctuations with second-order baryon diffusion coupled to chiral condensate

arXiv

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arXiv 2025年

作者： Sakai, Azumi Murase, Koichi Fujii, Hirotsugu Hirano, Tetsufumi Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Higashi-Hiroshima739-8526 Japan Department of Physics Sophia University Chiyoda Tokyo102-8554 Japan Department of Physics Tokyo Metropolitan University Hachioji Tokyo192-0397 Japan Yukawa Institute for Theoretical Physics Kyoto University Sakyo Kyoto606-8502 Japan International Politics and Economics Nishogakusha University Chiyoda Tokyo102-8336 Japan Institute of Physics Unviversity of Tokyo Meguro Tokyo153-8902 Japan

We develop a dynamical model to describe critical fluctuations in heavy-ion collisions, incorporating the baryon diffusion current and chiral condensate as dynamical degrees of freedom, to address their nontrivial scale separation. The model couples fluctuations of the chiral condensate σ with baryon density fluctuations n and the diffusion current ν based on a second-order diffusion equation with a finite relaxation time of the baryon diffusion τR. We analyze the spacetime evolution and these correlation functions of the fluctuations in one-dimensionally expanding background. We confirm that an appropriate relaxation time τR ensures causality. We show that propagating waves with finite τR split into two modes at the critical temperature due to a rapid change of kinetic coefficients. In the correlation functions, we find that dynamical σ blurs the structure and peak around the critical temperature. With finite τR, the effect of the critical fluctuations persists longer into the later stages of the evolution. These findings suggest importance of dynamical effects of the chiral condensate and baryon diffusion current in identifying critical-point signals in heavy-ion collisions, where the scale separation is nontrivial. Copyright © 2025, The Authors. All rights reserved.

关键词： Heavy ions

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BAQET: BRAM-aware Quantization for Efficient Transformer Inference via Stream-based Architecture on an FPGA 25

BAQET: BRAM-aware Quantization for Efficient Transformer Inf...

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Proceedings of the 2025 ACM/SIGDA International Symposium on Field programmable Gate Arrays

作者： Ling-Chi Yang Chi-Jui Chen Trung Le Bo-Cheng Lai Scott Hauck Shih-Chieh Hsu Institute of Electronics National Yang Ming Chiao Tung University Hsinchu Taiwan Graduate Degree Program of College of Electrical and Computer Engineering in National Yang Ming Chiao Tung University Hsinchu Taiwan Electrical and Computer Engineering in University of Washington Seattle USA Electrical and Computer Engineering University of Washington Seattle USA Physics University of Washington Seattle USA

ISBN: (纸本)9798400713965

FPGAs are a compelling substrate for supporting machine learning inference. Tools such as High-Level Synthesis and hls4ml can shorten the development cycle for deploying ML algorithms on FPGAs, but can struggle to handle the large on-chip storage needed for many of these models. In particular the high BRAM usage found in many of these flows can cause Place & Route failures during synthesis. In this paper we propose using a Simulated-Annealing based flow to perform BRAM-aware quantization. This approach trades off inference accuracy with BRAM usage, to provide a high-quality inference engine that still meets on-chip resource constraints. We demonstrate this flow for Transformer-based machine learning algorithms, which include Flash Attention in a Stream-based Dataflow architecture. Our system imposes minimal accuracy drops, yet can reduce BRAM usage by 20%-50%, and improve power efficiency by 264%-812% compared to existing Transformer-based accelerators on FPGAs

关键词： efficient transformer

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Application of online science practicum by using Microsoft Teams and Learning Management System (LMS) during the Covid 19 pandemic 10

Application of online science practicum by using Microsoft T...

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10th National physics Seminar, SNF 2021

作者： Pertiwi, W.A. Sanjaya, L.A. Nadiyah Hasirah Haramen, M. Budi, A.S. Zarvianti, E. Puspa, R.W.D. Sianipar, L.K. Qoiriyah, W. Sitompul, H. Islamic Education Management Study Program Faculty Islamic of Education and Teacher Training Muhammad Azim Institute Jambi Indonesia Department of Physics Faculty of Mathematics and Natural Science Universitas Negeri Jakarta Indonesia Sharia Economics Study Program Faculty of Sharia and Law Muhammad Azim Islamic Institute Jambi Indonesia Physics Education Study Program STKIP Muhammadiyah Sungai Penuh Indonesia Kartika VIII-1 Senior High School Jakarta Indonesia Department of Physics Education Universitas Pelita Harapan Tangerang15811 Indonesia Informatics Engineering Study Program Faculty of Engineering Sheikh Yusuf Islamic University Tangerang Indonesia

The research objective of this is to see how to apply science practicum online using Microsoft Teams and Learning Management System (LMS). The form of this research is classroom action research which aims to apply the online science practicum during the Covid 19 pandemic. Therefore, it is carried out using two cycles in the application of online science practicum. The subjects of this study were students of the seventh semester in the Natural Science practicum course. Through observation and evaluation, it is shown that in the cycle I the percentage of practicum implementation which includes aspects of preparation, process and data and practicum results is 87.5%, in cycle II it has increased to 92.5%. In the assessment aspect of the practicum report, the average practicum assessment obtained in the first cycle was 3.09 from the highest score of 4 and in the second cycle was 3.7, while the aspect of student knowledge about the use of the Microsoft team which was taken using google form was 93%. In the aspect of student knowledge about the use of Learning Management System (LMS) by 75% and aspects of student understanding in the implementation of online science practicum using Microsoft Teams by 75%. © 2021 Institute of physics Publishing. All rights reserved.

关键词： Students

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Protomon: A Multimode Qubit in the Fluxonium Molecule

arXiv

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arXiv 2024年

作者： Kumar, Shashwat You, Xinyuan Croot, Xanthe Zhao, Tianpu Chen, Danyang Sussman, Sara Premkumar, Anjali Bryon, Jacob Koch, Jens Houck, Andrew A. Department of Electrical and Computer Engineering Princeton University PrincetonNJ08544 United States Northwestern–Fermilab Center for Applied Physics and Superconducting Technologies Northwestern University EvanstonIL60208 United States Graduate Program in Applied Physics Northwestern University EvanstonIL60208 United States Department of Physics Princeton University PrincetonNJ08544 United States Department of Physics and Astronomy Northwestern University EvanstonIL60208 United States

Qubits that are intrinsically insensitive to depolarization and dephasing errors promise to significantly reduce the overhead of fault-tolerant quantum computing. At their optimal operating points, the logical states of these qubits exhibit both exponentially suppressed matrix elements and sweet spots in energy dispersion, rendering the qubits immune to depolarization and dephasing, respectively. We introduce a multimode qubit, the protomon, encoded in a fluxonium molecule circuit. Compared to the closely related 0–π qubit, the protomon offers several advantages in theory: resilience to circuit parameter disorder, minimal dephasing from intrinsic harmonic modes, and no dependence on static offset charge. As a proof of concept, we realize four protomon qubits. By tuning the qubits to various operating points identified with calibrated two-tone spectroscopy, we measure depolarization times ranging from 64 to 73 µs and dephasing times between 0.2 to 0.5 µs for one selected qubit. The discrepancy between the relatively short measured coherence times and theoretical predictions is not fully understood. This calls for future studies investigating the limiting noise factors, informing the direction for improving coherence times of the protomon qubit. © 2024, CC BY.

关键词： Qubits

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Evaluation of an MR-compatible Power Supplying Solution for a Second-Generation RF-Penetrable Brain TOF-PET Insert for Simultaneous PET/MRI

Evaluation of an MR-compatible Power Supplying Solution for ...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： M.N. Ullah Q. Dong J. Fisher D. Innes R. D. Watkins C. S. Levin Department of Radiology Stanford University Stanford California United States of America Departments of Electrical Engineering Stanford University Stanford California United States of America Department of Electrical Engineering Bioengineering and Physics and Molecular Imaging Program at Stanford (MIPS) Stanford University Stanford California United States of America

ISBN: (数字)9798350388152

ISBN: (纸本)9798350388169

We present the development of a modular power supply unit (MPSU) tailored for the PETCoil Gen II, a magnetic resonance (MR)-compatible radio-frequency (RF) penetrable Time of Flight Positron Emission Tomography (TOF-PET) insert with substantial power demands ($\approx 1000 \mathrm{~W}$). The MPSU integrates off-the-shelf switching power supplies, custom MR-compatible coaxial cables, a linear power-regulating unit (LPRU), and an RF shielding cage. A liquid cooling system was implemented to address the overheating issues and maintain optimal detector performance. Our stability test shows consistent PET scanner performance, with an energy resolution and coincidence time resolution (CTR) of $11.74 \pm 0.03 \%$ full-width-half-maximum (FWHM) and $238 \pm 0.5 \mathrm{ps}$ FWHM, respectively, over a 10 -hour-long stability test. Stable temperatures of $20 \pm 0.1 \circ \mathrm{C}$ and $45 \pm 1.4{ }^{\circ} \mathrm{C}$ are recorded for PET detector modules and LPRU, respectively, during a 10-hour study. The developed power system offers a modular, MR-compatible, low-noise, and high-power solution for our second-generation RF-Penetrable Brain TOF-PET Insert for simultaneous PET/MRI scanning

关键词： Radio frequency Microwave integrated circuits Power demand Semiconductor detectors Energy resolution Magnetic resonance Switches

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Regenerative Braking System in E-Trike: Interval Type-2 Fuzzy Logic Control to Enhance Driving Range

Regenerative Braking System in E-Trike: Interval Type-2 Fuzz...

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International Conference on Technology, Informatics, Management, engineering, and Environment (TIME-E)

作者： Muhammad Rizalul Wahid Endra Joelianto Bentang Arief Budiman Doctoral Program in Engineering Physics Institut Teknologi Bandung Bandung Indonesia Mechatronics and Artificial Intelligence Universitas Pendidikan Indonesia Bandung Indonesia Instrumentation Control and Automation Research Group Institut Teknologi Bandung Bandung Indonesia Faculty of Mechanical and Aerospace Engineering Institut Teknologi Bandung Bandung Indonesia

ISBN: (数字)9798350364750

ISBN: (纸本)9798350364767

Electric vehicles (EV s) boast zero tailpipe emissions, directly improving air quality and lowering greenhouse gas emissions. Despite the promise of EVs for sustainable transportation, their limited range is a key challenge. Regenerative braking is a promising approach for enhancing the driving range. This research proposes a study of Interval Type-2 Fuzzy Logic (IT2FL) control to improve regenerative braking efficiency in an electric trike. Employing IT2FL control for regenerative braking recovers 35.84% of energy, translating to a 91.053 km increase in driving range. The IT2FL method achieved a range of 50 km/kWh, representing a significant 41.7% improvement. Furthermore, utilizing the Nie-Tan Method reducer within the IT2FL framework could extend the range by an additional 2.3 km, resulting in a 3 % increase in energy recovery. These findings demonstrate the effectiveness of IT2FL control in enhancing regenerative braking efficiency for the electric trike.

关键词： Fuzzy logic Electric potential Transportation Electric vehicles Air quality Informatics Greenhouse gases

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HADOKEN: An Open-Source Software Package for Predicting Electron Confinement Effects in Various Nanowire Geometries and Configurations

arXiv

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arXiv 2022年

作者： Wong, Bryan M. Chevalier, Cameron Department of Chemical & Environment Engineering Materials Science & Engineering Program Department of Physics & Astronomy Department of Chemistry University of California-Riverside RiversideCA92521 United States

We present an open-source software package, HADOKEN (High-level Algorithms to Design, Optimize, and Keep Electrons in Nanowires), for predicting electron confinement/localization effects in nanowires with various geometries, arbitrary number of concentric shell layers, doping densities, and external boundary conditions. The HADOKEN code is written in the MATLAB programming environments to aid in its readability and general accessibility to both users and practitioners. We provide several examples and outputs on a variety of different nanowire geometries, boundary conditions, and doping densities to demonstrate the capabilities of the HADOKEN software package. As such, the use of this predictive and versatile tool by both experimentalists and theorists could lead to further advances in both understanding and tailoring electron confinement effects in these nanosystems. © 2022, CC BY.

关键词： Poisson equation

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AI for organic and polymer synthesis

引用

Science China Chemistry 2024年第8期67卷 2461-2496页

作者： Xin Hong Qi Yang Kuangbiao Liao Jianfeng Pei Mao Chen Fanyang Mo Hua Lu Wen-Bin Zhang Haisen Zhou Jiaxiao Chen Lebin Su Shuo-Qing Zhang Siyuan Liu Xu Huang Yi-Zhou Sun Yuxiang Wang Zexi Zhang Zhunzhun Yu Sanzhong Luo Xue-Feng Fu Shu-Li You Center of Chemistry for Frontier Technologies Department of ChemistryZhejiang UniversityHangzhou 310027China Center of Basic Molecular Science Department of ChemistryTsinghua UniversityBeijing 100084China Guangzhou National Laboratory Guangzhou 510005China Center for Quantitative Biology Academy for Advanced Interdisciplinary StudiesPeking UniversityBeijing 100871China State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai 200433China School of Materials Science and Engineering Peking UniversityBeijing 100871China Beijing National Laboratory for Molecular Sciences Center for Soft Matter Science and EngineeringKey Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China AI for Science(AI4S)-Preferred Program Shenzhen Graduate SchoolPeking UniversityShenzhen 518055China State Key Laboratory of Chemical Biology Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200032China Department of Chemical Sciences National Natural Science Foundation of ChinaBeijing 100085China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Recent years have witnessed the transformative impact from the integration of artificial intelligence with organic and polymer synthesis. This synergy offers innovative and intelligent solutions to a range of classic problems in synthetic chemistry. These exciting advancements include the prediction of molecular property, multi-step retrosynthetic pathway planning, elucidation of the structure-performance relationship of single-step transformation, establishment of the quantitative linkage between polymer structures and their functions, design and optimization of polymerization process, prediction of the structure and sequence of biological macromolecules, as well as automated and intelligent synthesis platforms. Chemists can now explore synthetic chemistry with unprecedented precision and efficiency, creating novel reactions, catalysts, and polymer materials under the datadriven paradigm. Despite these thrilling developments, the field of artificial intelligence(AI) synthetic chemistry is still in its infancy, facing challenges and limitations in terms of data openness, model interpretability, as well as software and hardware support. This review aims to provide an overview of the current progress, key challenges, and future development suggestions in the interdisciplinary field between AI and synthetic chemistry. It is hoped that this overview will offer readers a comprehensive understanding of this emerging field, inspiring and promoting further scientific research and development.

关键词： organic synthesis polymer synthesis machine learning prediction chemical database automated synthesis

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