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Chinese Journal of Aeronautics 2024年第2期37卷 81-92页

作者： Mikhail PETROV Sofia ZIMINA Moscow institute of physics&technology Dolgoprudny 141701Russia

When carrying out calculations for turbulent flow simulation,one inevitably has to face the choice between accuracy and speed of *** order to simultaneously obtain both a computationally efficient and more accurate model,a surrogate model can be built on the basis of some fast special model and knowledge of previous calculations obtained by more accurate base models from various test bases or some results of serial *** objective of this work is to construct a surrogate model which allows to improve the accuracy of turbulent calculations obtained by a special model on unstructured *** this purpose,we use 1D Convolutional Neural Network(CNN)of the encoder-decoder architecture and reduce the problem to a single dimension by applying space-filling *** an approach would have the benefit of being applicable to solutions obtained on unstructured *** this work,a non-local approach is applied where entire flow fields obtained by the special and base models are used as input and ground truth output ***-Allmaras(SA)model and Near-wall Domain Decomposition(NDD)method for SA are taken as the base and special models *** efficiency and accuracy of the obtained surrogate model are demonstrated in a case of supersonic flow over a compression corner with different values for angleαand Reynolds number *** conducted an investigation into interpolation and extrapolation by Re and also into interpolation byα.

关键词： Space-filling curves Convolutional neural network Domain decomposition Turbulent flows Unstructured mesh

Effect of distribution shape on the melting transition, local ordering,and dynamics in a model size-polydisperse two-dimensional fluid

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Chinese physics B 2024年第7期33卷 419-428页

作者： Jackson Pame Lenin SShagolsem Department of physics National Institute of Technology ManipurImphalIndia

We study the effect of particle size polydispersity(δ) on the melting transition(T*), local ordering, solid–liquid coexistence phase and dynamics of two-dimensional Lennard–Jones fluids up to moderate polydispersity by means of computer simulations. The particle sizes are drawn at random from the Gaussian(G) and uniform(U) distribution *** these systems, we further consider two different kinds of particles, viz., particles having the same mass irrespective of size, and in the other case the mass of the particle scales with its size. It is observed that with increasing polydispersity,the value of T*initially increases due to improved packing efficiency(φ) followed by a decrease and terminates at δ ≈8%(U-system) and 14%(G-system) with no significant difference for both mass types. The interesting observation is that the particular value at which φ drops suddenly coincides with the peak of the heat capacity(CP) curve, indicating a transition. The quantification of local particle ordering through the hexatic order parameter(Q_6), Voronoi construction and pair correlation function reveals that the ordering decreases with increasing δ and T. Furthermore, the solid–liquid coexistence region for the G-system is shown to be comparatively wider in the T –δ plane phase diagram than that for the U system. Finally, the study of dynamics reveals that polydisperse systems relax faster compared to monodisperse systems;however, no significant qualitative differences, depending on the distribution type and mass polydispersity, are observed.

关键词： polydispersity ordering phase diagram dynamics

Remote sensing of air pollution incorporating integrated-path differential-absorption and coherent-Doppler lidar

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Defence technology（防务技术） 2024年第1期31卷 594-601页

作者： Ze-hou Yang Yong Chen Chun-li Chen Yong-ke Zhang Ji-hui Dong Tao Peng Xiao-feng Li Ding-fu Zhou School of physics Beijing Institute of TechnologyBeijing 100081China Southwest institute of Technical physics Chengdu 610041SichuanChina School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China

An innovative complex lidar system deployed on an airborne rotorcraft platform for remote sensing of atmospheric pollution is proposed and *** system incorporates integrated-path differential absorption lidar(DIAL) and coherent-doppler lidar(CDL) techniques using a dual tunable TEA CO_(2)laser in the 9—11 μm band and a 1.55 μm fiber *** combining the principles of differential absorption detection and pulsed coherent detection,the system enables agile and remote sensing of atmospheric *** static tests validate the system’s real-time detection capabilities,including the measurement of concentration-path-length product(CL),front distance,and path wind speed of air pollution plumes over long distances exceeding 4 *** experiments is conducted with the *** of the pollutant concentration and the wind field is carried out in an approximately 1 km slant range over scanning angle ranges from 45°to 65°,with a radial resolution of 30 m and10 *** test results demonstrate the system’s ability to spatially map atmospheric pollution plumes and predict their motion and dispersion patterns,thereby ensuring the protection of public safety.

关键词： Differential absorption LIDAR Coherent Doppler lidar Remoting sensing Atmospheric pollution

Phase-field simulations of the effect of temperature and interface for zirconiumδ-hydrides

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Chinese physics B 2024年第4期33卷 701-710页

作者：陈子航盛杰刘瑜施小明黄厚兵许可王越超武帅孙博刘海风宋海峰 School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Advanced Research institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081China Laboratory of Computational physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Department of physics University of Science and Technology BeijingBeijing 100083China

Hydride precipitation in zirconium cladding materials can damage their integrity and *** temperature and material defects have a significant effect on the dynamic growth of *** this study,we have developed a phasefield model based on the assumption of elastic behaviour within a specific temperature range(613 K-653 K).This model allows us to study the influence of temperature and interfacial effects on the morphology,stress,and average growth rate of zirconium *** results suggest that changes in temperature and interfacial energy influence the length-to-thickness ratio and average growth rate of the hydride *** ultimate determinant of hydride orientation is the loss of interfacial coherency,primarily induced by interfacial dislocation defects and quantifiable by the mismatch degree *** escalation in interfacial coherency loss leads to a transition of hydride growth from horizontal to vertical,accompanied by the onset of redirection ***,redirection occurs at a critical mismatch level,denoted as qc,and remains unaffected by variations in temperature and interfacial ***,this redirection leads to an increase in the maximum stress,which may influence the direction of hydride crack *** research highlights the importance of interfacial coherency and provides valuable insights into the morphology and growth kinetics of hydrides in zirconium alloys.

关键词： zirconium hydride phase-field method temperature effect mismatch degree

Motion of charged particles in bright squeezed vacuum

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Light(Science & Applications) 2024年第2期13卷 347-353页

作者： Matan Even Tzur Oren Cohen Solid State institute and physics Department Technion-Israel Institute of TechnologyHaifa3200003Israel

The motion of laser-driven electrons quivers with an average energy termed pondermotive *** explore electron dynamics driven by bright squeezed vacuum(BSV),finding that BSV induces width oscillations,akin to electron quivering in laser light,with an equivalent ponderomotive *** identify closed and open trajectories of the electronic width that are associated with high harmonic generation and above-threshold ionization,respectively,similarly to trajectories of the electron position when its motion is driven by coherent *** the case of bound electrons,the width oscillations may lead to ionization with noisy sub-cycle *** results are foundational for strong-field and free-electron quantum optics,as they shed light on ionization,high harmonic generation,and nonlinear Compton scattering in BSV.

关键词： structure vacuum ionization

Ward identities under the frame transformations in curved space-time

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Communications in Theoretical physics 2024年第9期76卷 109-119页

作者： Susobhan Mandal Department of physics Indian Institute of Technology Bombay

Scalar-tensor theories of gravity are considered to be competitors to Einstein's theory of general relativity for the description of classical gravity, as they are used to build feasible models for cosmic inflation. These theories can be formulated both in the Jordan and Einstein frame, which are related by a Weyl transformation with a field transformation, known together as a frame transformation. These theories formulated in the above two frames are often considered to be equivalent from the point of view of classical theory. However, this is no longer true from the quantum field theoretical perspective. In the present article, we show that the Ward identities derived in the above two frames are not connected through the frame transformation. This shows that the quantum field theories formulated in these two frames are not equivalent to each ***, this inequivalence is also shown by comparing the effective actions derived in these two frames.

关键词： curved spacetime frame transformations ward identities

Discovery of controllable high Chern number quantum anomalous Hall state in tetragonal lattice FeSIn

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Chinese physics B 2024年第6期33卷 504-509页

作者：任小浪张昌文 School of physics and technology Institute of SpintronicsUniversity of JinanJinan 250022China

Quantum anomalous Hall(QAH) insulators have excellent properties driven by fancy topological physics, but their practical application is greatly hindered by the observed temperature of liquid nitrogen, and the QAH insulator with high Chern number is conducive to spintronic devices with lower energy consumption. Here, we find that monolayer Fe SIn is a good candidate for realizing the QAH phase;it exhibits a high magnetic transition temperature of 221 K and tunable C = ±2 with respect to magnetization orientation in the y–z plane. After the application of biaxial strain, the magnetic axis shifts from the x–y plane to the z direction, and the effect of the high C and ferromagnetic ground state on the stress is robust. Also, the effect of correlation U on C has been examined. These properties are rooted in the large size of the Fe atom that contributes to ferromagnetic kinetic exchange with neighboring Fe atoms. These findings demonstrate monolayer Fe SIn to be a major template for probing novel QAH devices at higher temperatures.

关键词： high Chern number Weyl semimetals quantum anomalous Hall insulator magnetic transition temperature

Electronic property and topological phase transition in a graphene/CoBr_(2) heterostructure

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Chinese physics B 2024年第2期33卷 498-505页

作者：秦元秀李胜世纪维霄张昌文 School of physics and technology Institute of SpintronicsUniversity of JinanJinan 250022China

Recently,significant experimental advancements in achieving topological phases have been reported in van der Waals(vdW)heterostructures involving ***,using first-principles calculations,we investigate graphene/CoBr_(2)(Gr/CoBr_(2))heterostructures and find that an enhancement of in-plane magnetic anisotropy(IMA)energy in monolayer CoBr_(2) can be accomplished by reducing the interlayer distance of the vdW *** addition,we clarify that the enhancement of IMA energy primarily results from two factors:one is the weakness of the Co-d_(xy) and Co-d_(x^(2)-y^(2)) orbital hybridization and the other is the augmentation of the Co-d_(yz) and Co-d_(z)2 orbital ***,calculation results suggest that the Kosterlitz–Thouless phase transition temperature(TKT)of a 2D XY magnet Gr/CoBr_(2)(23.8 K)is higher than that of a 2D XY monolayer CoBr_(2)(1.35 K).By decreasing the interlayer distances,the proximity effect is more pronounced and band splitting ***,by taking into account spin–orbit coupling,a band gap of approximately 14.3 meV and the quantum anomalous Hall effect(QAHE)are attained by decreasing the interlayer distance by 1.0 *** by the above conclusions,we design a topological field transistor device *** results support that the vdW interlayer distance can be used to modulate the IMA energy and QAHE of materials,providing a pathway for the development of new low-power spintronic devices.

关键词： van der Waals heterostructure in-plane magnetic anisotropy energy quantum anomalous Hall effect

Excitonic Instability in Ta2Pd3Te5 Monolayer

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Chinese physics Letters 2024年第09期41卷 50-55页

作者： Jingyu Yao Haohao Sheng Ruihan Zhang Rongtian Pang Jin-Jian Zhou Quansheng Wu Hongming Weng Xi Dai Zhong Fang Zhijun Wang Beijing National Laboratory for Condensed Matter physics and Institute of PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences Centre for Quantum physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) School of Physics Beijing Institute of Technology Department of physics Hong Kong University of Science and Technology

By systematic theoretical calculations, we reveal an excitonic insulator（EI） in the Ta2Pd3Te5monolayer. The bulk Ta2Pd3Te5is a van der Waals（vdW） layered compound, whereas the vdW layer can be obtained through exfoliation or molecular-beam epitaxy. First-principles calculations show that the monolayer is a nearly zero-gap semiconductor with the modified Becke–Johnson functional.

关键词： CONDENSATION SIGNATURES PHASE

Plasmon-assisted mode selection lasing in a lanthanide-based microcavity

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Advanced Photonics 2024年第3期6卷 35-41页

作者： Lei Guo Min Ji Bowen Kang Min Zhang Xin Xie Zihao Wu Huan Chen Volker Deckert Zhenglong Zhang Shaanxi Normal University School of Physics and Information Technology Friedrich-Schiller University Leibniz Institute of Photonic Technology

Lanthanide-based microlasers have attracted considerable attention owing to their large anti-Stokes shifts, multiple emission bands, and narrow linewidths. Various applications of microlasers, such as optical communication, optical storage, and polarization imaging, require selecting the appropriate laser polarization mode and remote control of the laser properties. Here, we propose a unique plasmon-assisted method for the mode selection and remote control of microlasing using a lanthanide-based microcavity coupled with surface plasmon polaritons(SPPs) that propagate on a silver microplate. With this method, the transverse electrical(TE) mode of microlasers can be easily separated from the transverse magnetic(TM) mode. Because the SPPs excited on the silver microplate only support TM mode propagation, the reserved TE mode is resonance-enhanced in the microcavity and amplified by the local electromagnetic field. Meanwhile, lasingmode splitting can be observed under the near-field excitation of SPPs due to the coherent coupling between the microcavity and mirror microcavity modes. Benefiting from the long-distance propagation characteristics of tens of micrometers of SPPs on a silver microplate, remote excitation and control of upconversion microlasing can also be realized. These plasmon-assisted polarization mode-optional and remote-controllable upconversion microlasers have promising prospects in on-chip optoelectronic devices, encrypted optical information transmission, and high-precision sensors.

关键词： lanthanide-based microlaser surface plasmon polaritons polarization mode selection