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arXiv 2022年

作者： Tan, Qing Yan, Zhiran Wang, Huijun dye, david Antonov, Stoichko Gault, Baptiste Department of Microstructure Physics and Alloy Design Max-Planck-Institut für Eisenforschung GmbH Max-Planck-Straße 1 Düsseldorf40237 Germany Department of Materials Royal School of Mines Imperial College Prince Consort Road LondonSW7 2BP United Kingdom State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing100083 China

The corrosion potential of commercially pure titanium in NaCl solutions is dramatically affected by trace Fe additions, which cause the appearance of submicron pockets of β phase at grain boundary triple points. Furthermore, the low solubility of hydrogen in hexagonal close-packed α-Ti makes titanium alloys prone to subsequent hydride-associated failures due to stress corrosion cracking. We analyzed α-α and α-β sections of the abutting grain boundary of a β pocket in a Grade 2 CP-Ti, and the α-β phase boundary. Fe and H partition to β and segregate at the grain boundary, but no segregation is seen at the α-β phase boundary. In contrast, a significant Ni (>1 at%) accumulation is observed at the α-β phase boundary. We propose that the β-pockets act as hydrogen traps and facilitate the nucleation and growth of hydrides along grain boundaries in CP-Ti. Copyright © 2022, The Authors. All rights reserved.

关键词： Grain boundaries

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Lane changing and merging support system with adaptive cruise control 15

Lane changing and merging support system with adaptive cruis...

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15th International Conference on Motion and Vibration Control, MoViC 2020

作者： Nishiwaki, Kazuhiro Iezawa, Masahiro Takahashi, Masaki Advanced Technology R&D Center Mitsubishi Electric Corporation 8-1-1 Tsukaguchi-Honmachi Amagasaki City Hyogo661-8661 Japan Department of System Design Engineering Keio University 3-14-1 Hiyoshi Kohoku-ku Yokohama223-8522 Japan

This paper presents lane changing and merging support system with adaptive cruise control (ACC). In lane changing and merging, drivers consider about safety and longitudinal ride comfort. In addition, drivers must finish merging in the acceleration lane. In order to achieve these objectives, we propose the merging decision and control method. The merging decision calculates several plans to merge in the acceleration lane, and selects the plan with smallest acceleration. 2 degree of freedom (2dOF) control is applied to the longitudinal and lateral control. In 2dOF control, the response is defined by the filter. The filter of the longitudinal control defines the reference distance for safe spacing to the surrounding vehicle, and the filter of the lateral control defines the reference path for changing lanes. The longitudinal and lateral control follows these references by the feedback controller and the feedforward controller. The performance of the proposed system is tested by simulations. In these simulations, the merging decision calculates the plan to finish merging in the acceleration lane with the smallest acceleration, and the longitudinal and lateral controller follows references accurately by the feedforward controller. These results show that the proposed system contributes the safe and comfortable lane changing and merging. © 2020 The Japan Society of Mechanical Engineers.

关键词： advanced driver assistance systems

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Phase-Field Modeling of Coupled Brittle-ductile Fracture in Aluminum Alloys

arXiv

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arXiv 2022年

作者： Vakili, Samad Shanthraj, Pratheek roters, Franz Mianroodi, Jaber r. raabe, dierk Microstructure Physics and Alloy Design Max-Planck-Institut für Eisenforschung Max-Planck-Straße 1 Düsseldorf40237 Germany The Department of Materials The University of Manchester ManchesterM13 9PL United Kingdom Henry Royce Institute for Advanced Materials The University of Manchester ManchesterM13 9PL United Kingdom

Fracture in aluminum alloys with precipitates involves at least two mechanisms, namely, ductile fracture of the aluminum-rich matrix and brittle fracture of the precipitates. In this work, a coupled crystal plasticity - phase field model for mixed ductile-brittle failure modes is formulated and used to investigate the effect of precipitate morphology and size distribution on damage evolution in aluminum alloys. A thermodynamically consistent framework for elastic and plastic work dissipation in the fracture process zone is used to formulate the coupled constitutive behavior for brittle and ductile damage, respectively. representative Volume Elements (rVE) with varying particle morphology and orientation were generated and their uni-axial loading was simulated to assess the damage resistance of the different model microstructures. For critical energy release rate (Gc) values of the aluminum matrix ranging from 4 to 8 Jm−2 for single crystals and from 10 to 16 Jm−2 for polycrystals, the model predicts a change in failure modes from particle debonding to cracking followed by ductile matrix failure. The change of particle failure mechanism as a result of increased critical energy release rate is observed for both, single and polycrystalline model microstructures. For the case of particle debonding, microstructures with circular or ellipsoidal particles (with the major axis perpendicular to the loading direction) show a higher ductility and fracture work compared to the other studied cases. In the case of particle cracking, microstructures with ellipsoidal particles aligned parallel to the loading axis show a higher ductility and fracture work among the investigated cases. The simulations qualitatively reproduce the experimentally observed particle failure mechanisms (cracking and debonding) for two different matrix alloy classes (commercially pure and 2xxx alloys) reinforced with ceramic particles. © 2022, CC BY.

关键词： ductile fracture

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Short period magnetization texture of B20-MnGe explained by thermally fluctuating local moments

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Physical review B 2021年第2期103卷 024410-024410页

作者： Eduardo Mendive-Tapia Manuel dos Santos dias Sergii Grytsiuk Julie B. Staunton Stefan Blügel Samir Lounis Department of Computational Materials Design Max-Planck-Institut für Eisenforschung 40237 Düsseldorf Germany Peter Grünberg Institut and Institute for Advanced Simulation Forschungszentrum Jülich and JARA 52425 Jülich Germany Department of Physics University of Warwick Coventry CV4 7AL United Kingdom Faculty of Physics University of Duisburg-Essen 47053 Duisburg Germany

B20-type compounds, such as MnSi and FeGe, host helimagnetic and skyrmion phases at the mesoscale, which are canonically explained by the combination of ferromagnetic isotropic interactions with weaker chiral dzyaloshinskii-Moriya ones. Mysteriously, MnGe evades this paradigm as it displays a noncollinear magnetic state at a much shorter nanometer scale. Here we show that the length scale and volume-dependent magnetic properties of MnGe stem from purely isotropic exchange interactions, generally obtained in the paramagnetic state. Our approach is validated by comparing MnGe with the canonical B20-helimagnet FeGe. The free energy of MnGe is calculated, from which we show how triple-q magnetic states can stabilize by adding higher-order interactions.

关键词： Helicoidal magnetic texture Magnetic interactions Magnetic phase transitions Magnetic texture Thermal properties Magnetic systems Noncentrosymmetric materials Transition metal alloys density functional theory First-principles calculations Korringa-Kohn-rostoker method Magnetism

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Technologies for performance intensification of floating treatment wetland – An explicit and comprehensive review

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Chemosphere 2024年 348卷 140727页

作者： Zhang, Fuhao Wang, Jie Li, Liyuan Shen, Cheng Zhang, Shaochen Zhang, Jin Liu, ranbin Zhao, Yaqian Key Laboratory of Recycling and Eco-Treatment of Waste Biomass of Zhejiang Province Zhejiang University of Science and Technology Hangzhou310023 China State Key Laboratory of Eco-Hydraulics in Northwest Arid Region Xi'an University of Technology Xi'an710048 China Department of Municipal and Environmental Engineering School of Water Resources and Hydroelectric Engineering Xi'an University of Technology Xi'an710048 China Dooge Centre for Water Resources Research School of Civil Engineering University College Dublin Dublin 4 Belfield Ireland Sino-Dutch R&D Centre for Future Wastewater Treatment Technologies/Beijing Advanced Innovation Center of Future Urban Design Beijing University of Civil Engineering & Architecture Beijing100044 China

With the wide application of floating treatment wetland (FTW), the limited performance of FTWs should be improved. A comprehensive review is accordingly necessary to summarize the state-of-the-art on FTWs for performance improvement. An attempt has been made to gain information from literature about technologies to enhance the performance of FTWs. These technologies have been classified into three categories according to their mechanisms: 1) increasing the amount and activity of bacteria;2) enhancing the growth of plant;and 3) configurable innovations. The design and application of each enhanced FTW have been discussed in detail. Thereafter, all the technologies have been compared and analyzed according to their improvement in pollutant removal and ecological effects. In summary, FTW with additional bio-carriers has a higher potential for future applications with the benefits of wide application conditions, scale-up potential, and the easy combination with other methods to further improve the removal efficiency. The stability and sustainability of these technologies should be further investigated. © 2023 Elsevier Ltd

关键词： Wetlands

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Variational quantum algorithm for generalized eigenvalue problems and its application to the finite-element method

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Physical review A 2023年第2期108卷 022429-022429页

作者： Yuki Sato Hiroshi C. Watanabe rudy raymond ruho Kondo Kaito Wada Katsuhiro Endo Michihiko Sugawara Naoki Yamamoto Toyota Central R&D Labs. Inc. 41-1 Yokomichi Nagakute Aichi 480-1192 Japan Quantum Computing Center Keio University 3-14-1 Hiyoshi Kohoku-ku Yokohama Kanagawa 223-8522 Japan Department of Chemistry Graduate School of Science Kyushu University 744 Motooka Nishi-ku Fukuoka 819-0395 Japan IBM Quantum IBM Japan 19-21 Nihonbashi Hakozaki-cho Chuo-ku Tokyo 103-8510 Japan Department of Computer Science The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-0033 Japan Department of Applied Physics and Physico-Informatics Keio University Hiyoshi 3-14-1 Kohoku-ku Yokohama 223-8522 Japan Research Center for Computational Design of Advanced Functional Materials National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono Tsukuba Ibaraki 305-8568 Japan

Generalized eigenvalue problems (GEPs) play an important role in the variety of fields including engineering, machine learning, and quantum chemistry. Especially, many problems in these fields can be reduced to finding the minimum or maximum eigenvalue of GEPs. One of the key problems to handle GEPs is that the memory usage and computational complexity explode as the size of the system of interest grows. This paper aims at extending sequential quantum optimizers for GEPs. Sequential quantum optimizers are a family of algorithms that iteratively solve the analytical optimization of single-qubit gates in a coordinate descent manner. The contribution of this paper is as follows. First, we formulate the GEP as the minimization or maximization problem of the fractional form of the expectations of two Hermitians. We then show that the fractional objective function can be analytically minimized or maximized with respect to a single-qubit gate by solving a GEP of a 4×4 matrix. Second, we show that a system of linear equations characterized by a positive-definite Hermitian can be formulated as a GEP and thus be attacked using the proposed method. Finally, we demonstrate two applications to important engineering problems formulated with the finite-element method. Through the demonstration, we have the following bonus finding; a problem having a real-valued solution can be solved more effectively using quantum gates generating a complex-valued state vector, which demonstrates the effectiveness of the proposed method.

关键词： Quantum algorithms

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In-situ synchrotron-based high energy X-ray diffraction study of the deformation mechanism of δ-hydride in a commercially pure titanium

arXiv

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arXiv 2022年

作者： Tan, Qing Yan, Zhiran Li, runguang ren, Yang Wang, Yandong Gault, Baptiste Antonov, Stoichko State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing100083 China Department of Microstructure Physics and Alloy Design Max-Planck-Institut für Eisenforschung GmbH Max-Planck-Straße 1 Düsseldorf40237 Germany Department of Materials Royal School of Mines Imperial College Prince Consort Road LondonSW7 2BP United Kingdom Department of Mechanical Engineering Technical University of Denmark LyngbyDK-2800 Kgs. Denmark X-ray Science Division Advanced Photon Source Argonne National Laboratory ArgonneIL60439 United States

We investigated the deformation behavior of Grade 2 commercially pure titanium that was hydrogen charged to form hydrides by in-situ high energy X-ray diffraction. The results showed that high internal and interphase stresses generated within and around hydrides due to the volume expansion induced by the phase transformation could lead to the peak broadening. Hydride behaves as typical high strength but brittle secondary phase, which undertakes more elastic strain than matrix and generates cracks first. This study on the deformation mechanism of hydrides in titanium provides insight into the hydride behavior and hydrogen embrittlement in both titanium and zirconium. Copyright © 2022, The Authors. All rights reserved.

关键词： Synchrotron radiation

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Optimal parameter configurations for sequential optimization of the variational quantum eigensolver

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Physical review research 2023年第4期5卷 043136-043136页

作者： Katsuhiro Endo Yuki Sato rudy raymond Kaito Wada Naoki Yamamoto Hiroshi C. Watanabe Research Center for Computational Design of Advanced Functional Materials National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono Tsukuba Ibaraki 305-8568 Japan Quantum Computing Center Keio University Hiyoshi 3-14-1 Kohoku-ku Yokohama 223-8522 Japan Toyota Central R & D Labs. Inc. Koraku Mori Building 10F 1-4-14 Koraku Bunkyo-ku Tokyo 112-0004 Japan IBM Quantum IBM Japan 19-21 Nihonbashi Hakozaki-cho Chuo-ku Tokyo 103-8510 Japan Department of Computer Science The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-0033 Japan Department of Applied Physics and Physico-Informatics Keio University Hiyoshi 3-14-1 Kohoku-ku Yokohama 223-8522 Japan Department of Chemistry Graduate School of Science Kyushu University 744 Motooka Nishi-ku Fukuoka 819-0395 Japan

The variational quantum eigensolver (VQE) is a hybrid algorithm to find the minimum eigenvalue/vector of the given Hamiltonian by optimizing a parameterized quantum circuit (PQC) using a classical computer. Sequential optimization methods, which are often used in quantum circuit tensor networks, are popular for optimizing the parameterized gates of PQCs. In this paper, we focus on the case where the components to be optimized are single-qubit gates, in which the analytic optimization of a single-qubit gate is sequentially performed. The analytical solution is given by diagonalization of a matrix whose elements are computed from the expectation values of observables specified by a set of predetermined parameters, which we refer to as the parameter configurations. In this paper, we first show that the optimization accuracy significantly depends on the choice of parameter configurations owing to the statistical errors in the expectation values. We then identify a metric that quantifies the optimization accuracy of a parameter configuration for all possible statistical errors, named configuration overhead/cost or C-cost. We theoretically provide the lower bound of C-cost and show that, for the minimum size of parameter configurations, the lower bound is achieved if and only if the parameter configuration satisfies the so-called equiangular line condition. Finally, we provide numerical experiments demonstrating that the optimal parameter configuration exhibits the best result in several VQE problems. We hope that this general statistical methodology will enhance the efficacy of sequential optimization of PQCs for solving practical problems with near-term quantum devices.

关键词： Quantum algorithms & computation Quantum circuits Quantum computation Quantum information processing Quantum measurements Quantum parameter estimation

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Erratum: Interrupted mosaic speech revisited: Gain and loss in intelligibility by stretching [J. Acoust. Soc. Am. 155(3), 1767-1779 (2024)]

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The Journal of the Acoustical Society of America 2024年第5期155卷 3014页

作者： Kazuo Ueda Masashi Hashimoto Hiroshige Takeichi Kohei Wakamiya Department of Acoustic Design Faculty of Design/Research Center for Applied Perceptual Science/Research and Development Center for Five-Sense Devices Kyushu University 4-9-1 Shiobaru Minami-ku Fukuoka 815-8540 Japan. Department of Acoustic Design Faculty of Design Kyushu University 4-9-1 Shiobaru Minami-ku Fukuoka 815-8540 Japan. Open Systems Information Science Team Advanced Data Science Project (ADSP) RIKEN Information R&D and Strategy Headquarters (R-IH) RIKEN 1-7-22 Suehiro-cho Tsurumi-ku Yokohama Kanagawa 230-0045 Japan.

In the second line of the abstract on page 1767 of the original paper (Ueda , 2024), read “Udea” as “Ueda.”

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A SWAP Gate for Spin Qubits in Silicon

arXiv

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arXiv 2023年

作者： Ni, Ming Ma, rong-Long Kong, Zhen-Zhen Xue, Xiao Zhu, Sheng-Kai Wang, Chu Li, Ao-ran Chu, Ning Liao, Wei-Zhu Cao, Gang Wang, Gui-Lei Guo, Guang-Can Hu, Xuedong Jiang, Hong-Wen Li, Hai-Ou Guo, Guo-Ping CAS Key Laboratory of Quantum Information University of Science and Technology of China Anhui Hefei230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Anhui Hefei230026 China Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China QuTech and Kavli Institute of Nanoscience Delft University of Technology Delft2628 CJ Netherlands Department of Physics University at Buffalo SUNY BuffaloNY14260 United States Department of Physics and Astronomy University of California Los AngelesCA90095 United States Beijing Superstring Academy of Memory Technology Beijing100176 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China Origin Quantum Computing Company Limited Anhui Hefei230026 China

With one- and two-qubit gate fidelities approaching the fault-tolerance threshold for spin qubits in Si, how to scale up the architecture and make large arrays of spin qubits become the more pressing challenges. In a scaled-up structure, qubit-to-qubit connectivity has crucial impact on gate counts of quantum error correction and general quantum algorithms. In our toolbox of quantum gates for spin qubits, SWAP gate is quite versatile: it can help solve the connectivity problem by realizing both short- and long-range spin state transfer, and act as a basic two-qubit gate, which can reduce quantum circuit depth when combined with other two-qubit gates. However, for spin qubits in silicon quantum dots, high fidelity SWAP gates have not been demonstrated due to the requirements of large circuit bandwidth and a highly adjustable ratio between the strength of the exchange coupling J and the Zeeman energy difference ∆Ez. Here we demonstrate a fast SWAP gate with a duration of ~25 ns based on quantum dots in isotopically enriched silicon, with a highly adjustable ratio between J and ∆Ez, for over two orders of magnitude in our device. We are also able to calibrate the single-qubit local phases during the SWAP gate by incorporating single-qubit gates in our circuit. By independently reading out the qubits, we probe the anti-correlations between the two spins, estimate the operation fidelity and analyze the dominant error sources for our SWAP gate. These results pave the way for high fidelity SWAP gates, and processes based on them, such as quantum communication on chip and quantum simulation by engineering the Heisenberg Hamiltonian in silicon. Copyright © 2023, The Authors. All rights reserved.

关键词： Qubits

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