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SSRN 2023年

作者： Yue, Jincheng Li, Junda Ma, Xuejiao Guo, Siqi Wang, Hongwei Shen, Chen Zhang, Ao Liu, Yanhui Cui, Tian Institute of High Pressure Physics School of Physical Science and Technology Ningbo University Ningbo315211 China Science and Technology on Transient Impact Laboratory No.208 Research Institute of Ordnance Industries Beijing102202 China Institute of Materials Science Technical University of Darmstadt Alarich-Weiss-Strasse 2 Darmstadt64287 Germany School of Physics Southeast University Nanjing211189 China

Copper-based sulfides have recently attracted prominence as prospective thermoelectric materials due to their high efficiency, abundance, and low toxicity. Meanwhile, the introduction of ionic alkali metals has been shown to be effective in avoiding device degradation caused by the liquid movement of Cu ions. Herein, we explore the thermoelectric transport properties of the novel copper-based chalcogenides CsCu3X2 (X = S, Se) combined with the first principles-based self-consistent phonon (SCPH) theory and the momentum relaxation-time approximation (MRTA). Notably, the CsCu3X2 (X = S, Se) exhibits an inherently ultra-low lattice thermal conductivity with 0.69-0.49 Wm-1K-1 at room temperature. The theoretical results demonstrate that the 3/4ph scattering involved in rattle-like coherent vibrations and the increased available phase space W3/4ph tremendously suppress the transportation of heat-carrying phonons. Moreover, the corresponding lower ionization potentials make these two compounds more suitable for p-type doping after determining the band alignment. The coexistence of electronic band degeneracy and high-dispersion band edges contributed to the high carrier mobility, which provides excellent electronic transport properties near the valence band. Ultimately, a maximum ZT value of 2.24 and 2.63 is captured for the p-type CsCu3S2 and CsCu3Se2 at 900 K, respectively. Our findings indicate the direction for the development of novel environmentally friendly copper-based chalcogenide thermoelectric materials in the future. © 2023, The Authors. All rights reserved.

关键词： Chalcogenides

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Reconstruction of attosecond beating by interference of two-photon transitions on the lithium atom with Rabi oscillations

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Physical Review A 2022年第6期105卷 063110-063110页

作者： Yijie Liao Yueming Zhou Liang-Wen Pi Jintai Liang Qinghua Ke Yong Zhao Min Li Peixiang Lu School of Physics and Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan 430074 China State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision Mechanics of the Chinese Academy of Sciences Xi'an 710119 China University of Chinese Academy of Science Beijing 100049 China Optics Valley Laboratory Hubei 430074 China

We present numerical simulations of the reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) on lithium by solving the three-dimensional time-dependent Schrödinger equation. In our scheme, the infrared (IR) field couples the 2s and 2p states of lithium and leads to the Rabi oscillations of populations between these two states. We analyzed the RABBITT phases of the two peaks in the Rabi-oscillation-induced Autler-Townes splittings. Our results show that the relative phase between these two peaks changes with the photoelectron energy and depends on the intensity of the IR field. Moreover, in the angle-resolved RABBITT measurement, the phases of the two peaks depend differently on the emission angle of photoelectrons. These behaviors are traced back to the different initial phases of the electron wave packets emitted from the dressed 2p states and the competition among different ionization channels.

关键词： Atomic spectra Light-matter interaction Single- and few-photon ionization & excitation

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Fuzzy Logic Algorithm of Projectile Electromechanical Actuator Control System

Fuzzy Logic Algorithm of Projectile Electromechanical Actuat...

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第40届中国控制会议

作者： Hongqiao Yin Wenjun Yi Cuicui Li Kangjian Wang Jun Guan National Key Laboratory of Transient Physics Nanjing University of Science and Technology School of Electronic Information Jiangsu University of Science and Technology

As an important actuator of guided projectile,the performance of electromechanical actuator(EMA) directly determines the strike precision of guided *** classical three closed loop proportional integral differential(PID) algorithm is a common control method in EMA *** at the disadvantages of low control accuracy and poor adaptability of traditional PID control,in order to improve the control accuracy and robustness of the EMA system,this paper designs a fuzzy parameter adaptive PI algorithm for automatic position regulator(APR) of the EMA control *** this paper,the mathematical model and operation characteristics of the EMA system are analyzed,and the deviation e,which between the rudder angle actual position and the set reference position,and the deviation change rate ec are taken as the input,the corresponding PI adjustment coefficient are taken as the output of the fuzzy *** rudder angle step function response is analyzed at the position of 3°,4°,5°,6°,7° and 8° ***,the results show that in projectile EMA control system,fuzzy parameter adaptive PI algorithm used in APR can make step response of the rudder angle have shorter rising time,faster response speed,smaller steady-state error and better robustness.

关键词： Electromechanical actuator classical PID control fuzzy control algorithm parameter adaptation

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Ballistic performance of perforated steel against explosively formed projectile impact

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International Journal of Mechanical sciences 2025年

作者： Yuanbo Li Jinxiang Wang Lingquan Kong Yunkun Hou Jian Wang Kui Tang Ming Yang Liangtao Liu National Key Laboratory of Transient Physics Nanjing University of Science and Technology Nanjing Jiangsu 210094 China

Lightweight protective structures face a critical challenge in simultaneously mitigating high-speed kinetic energy projectiles while maintaining structural efficiency. Honeycomb array perforated steel (HAPS) exhibits distinct protective performance against explosively formed projectiles (EFPs) compared to conventional bullets. A smooth particle hydrodynamics finite-element model numerical simulation and an experimental verification method were used to study the ballistic performance. An analysis was performed to assess the impact of the HAPS arrangement and EFP impact points on protective capabilities. The findings reveal that the protective efficacy is most pronounced when HAPS is placed between two layers of target panels. In the embedding damage mode, the maximum deformation of the back panel in the sandwich structure with HAPS decreased by 52.7% compared with the HAPS front configuration. In the penetration mode, the ballistic limit velocity increased by 9.9% compared with the HAPS front configuration. Moreover, the impact location and of the EFP and the cell size of HAPS influences the EFP's penetration capability, with the asymmetric contact between the HAPS and the EFP enhancing the resistance of the structure. Petallike perforations were observed at the rear of the HAPS. These discoveries provide insight into the development of protective structures and offer valuable perspectives for structural design and applications in related fields.

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Study on differential mode conducted interference of trigger circuit of high-power thyristors in pulsed power supply 2

Study on differential mode conducted interference of trigger...

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2nd Spring International Conference on Defence technology, ICDT 2020

作者： Wei, Jiu-Fu Liu, Xiang-Rong Luo Li, Zhen-Xiao Li, Bao-Ming National Key Laboratory of Transient Physics Nanjing University of Science and Technology Nanjing China China Academy of Ordnance Science Beijing China

The trigger circuits of high-power thyristors in pulsed power supply (PPS) contain a large number of pulse transformers, switching MOSFETs (SMFETs) and other passive devices. Fast on-off of SMFETs and pulse transformers often lead to differential mode conducted interference (DMCI) problems in trigger circuits of high-power thyristors. This paper mainly disscusses DMCI problems in trigger circuits of high-power thyristors in the following aspects: initially, circuit models of high-frequency parasitic parameters of pulse transformer and SMFET are established;next, principles of DMCI in trigger circuits of high-power thyristors are investigated;furthermore, DMCI suppression methods are also analyzed;ultimately, experiments have been carried out to verify the theoretical analysis. © Published under licence by IOP Publishing Ltd.

关键词： Trigger circuits

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Study on the Influence of Shaft Brackets on the Scale Effect of the Four-Screw Ship Wake Field

SSRN

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SSRN 2023年

作者： Ma, Wenxuan Chang, Xin Wang, Wenquan Sun, Shuai Chen, Qiuying Naval Architecture and Ocean Engineering College Dalian Maritime University Dalian116026 China Marine Design and Research Institute of China Shanghai200011 China National Key Laboratory of Transient Physics Nanjing University of Science and Technology Nanjing210094 China

Multi-scale simulations of a four-screw ship were carried out using the Reynolds-averaged Navier-Stokes (RANS) method. The difference in the scale effect of the wake field of a ship with and without the shaft brackets is investigated. The feasibility and accuracy of the numerical method was verified by comparing the numerical results with corresponding experimental observations. The result shows that the scale effect of the outer propeller is greater than that of the inner propeller, and the scale effect of the inner radius region is greater than the outer radius region. The influence of the shaft brackets on the inner radius of the outer propeller disc is most obvious. When the bracket is less than the critical Reynolds number, there is a significant deviation between the model flow field in this region and the full-scale flow field, resulting in the loss of practical significance of the model results. It is proved that the bracket is one of the causes of the load difference between the inner and outer propellers during actual navigation of a four-screw ship. © 2023, The Authors. All rights reserved.

关键词： Screws

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Study on the Influence of Shaft Brackets on the Scale Effect of the Four-Screw Ship Wake Field

SSRN

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SSRN 2023年

Multi-scale simulations of a four-screw ship were carried out using the Reynolds-averaged Navier-Stokes (RANS) method. The difference in the scale effect of the wake field of a ship with and without the shaft brackets is investigated. The feasibility and accuracy of the numerical method was verified by comparing the numerical results with corresponding experimental observations. The result shows that the scale effect of the outer propeller is greater than that of the inner propeller, and the scale effect of the inner radius region is greater than the outer radius region. The influence of the shaft brackets on the inner radius of the outer propeller disc is most obvious. When the bracket is less than the critical Reynolds number, there is a significant deviation between the model flow field in this region and the full-scale flow field, resulting in the loss of practical significance of the simulation results. It is proved that the bracket is one of the causes of the load difference between the inner and outer propellers during actual navigation of a four-screw ship. © 2023, The Authors. All rights reserved.

关键词： Screws

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High-performance γ-MnO_(2) Dual-Core,Pair-Hole Fiber for Ultrafast Photonics

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Ultrafast science 2023年第1期3卷 19-25页

作者： Xiaohui Li Xiangzhen Huang Yueheng Han Enci Chen Penglai Guo Wenmin Zhang Mingqi An Zhiwen Pan Qian Xu Xiaoxiao Guo Xiwei Huang Yishan Wang Wei Zhao School of Physics and Information Technology Shaanxi Normal UniversityXian 710000ShaanxiChina School of Electronic Engineering Guangxi University of Science and TechnologyLiuzhou 545006GuangxiChina Schoolof Computer Science and Engineering Macao University of Science and TechnologyTaipa 999078MacaoChina State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision MechanicsChinese Academy of SciencesXi'an 710119ShaanxiChina

Manganese dioxide(MnO2)is a widely used and well-studied 3-dimensional(3D)transition metal oxide,which has advantages in ultrafast optics due to large specific surface area,narrow bandgap,multiple pores,superior electron transfer capability,and a wide range of light ***,few studies have considered its excellent performance in ultrafast photonics.y-MnO2 photonics devices were fabricated based on a special dual-core,pair-hole fiber(DCPHF)carrier and applied in ultrafast optics fields for the first *** results show that the soliton molecule with tunable temporal separation(1.84 to 2.7 ps)and 600-MHz harmonic solitons are achieved in the *** result proves that this kind of photonics device has goodapplications in ultrafast lasers,high-performance sensors,fiber optical communications,etc.,which can help expand the prospect of combining 3D materials with novel fiber for ultrafast optics device technology.

关键词： fiber optics performance

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Atom-referenced on-chip soliton microcomb

arXiv

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arXiv 2023年

作者： Niu, Rui Wan, Shuai Hua, Tian-Peng Wang, Wei-Qiang Wang, Zheng-Yu Li, Jin Wang, Zhu-Bo Li, Ming Shen, Zhen Sun, Y.R. Hu, Shui-Ming Little, B.E. Chu, S.T. Zhao, Wei Guo, Guang-Can Zou, Chang-Ling Xiao, Yun-Feng Zhang, Wen-Fu Dong, Chun-Hua 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 State Key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi’an710119 China University of Chinese Academy of Sciences Beijing100049 China Department of Chemical Physics University of Science and Technology of China Hefei230026 China Department of Physics and Materials Science City University of Hong Kong Kowloon Tong Hong Kong State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of Physics Peking University Beijing China

For the applications of the frequency comb in microresonators, it is essential to obtain a fully frequency-stabilized microcomb laser source. Here, we demonstrate an atom-referenced stabilized soliton microcomb generation system based on the integrated microring resonator. The pump light around 1560.48 nm locked to an ultra-low-expansion (ULE) cavity, is frequency-doubled and referenced to the atomic transition of 87Rb. The repetition rate of the soliton microcomb is injection-locked to an atomic-clock-stabilized radio frequency (RF) source, leading to mHz stabilization at 1 seconds. As a result, all comb lines have been frequency-stabilized based on the atomic reference and could be determined with very high precision reaching ∼ 18 Hz at 1 second, corresponding to the frequency stability of 9.5 × 10−14. Our approach provides an integrated and fully stabilized microcomb experiment scheme with no requirement of f − 2f technique, which could be easily implemented and generalized to various photonic platforms, thus paving the way towards the portable and ultraprecise optical sources for high precision spectroscopy. Copyright © 2023, The Authors. All rights reserved.

关键词： Solitons

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Discrete Boltzmann modeling of Rayleigh-Taylor instability: effects of interfacial tension, viscosity and heat conductivity

arXiv

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arXiv 2022年

作者： Chen, Jie Xu, Aiguo Chen, Dawei Zhang, Yudong Chen, Zhihua Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics P. O. Box 8009-26 Beijing100088 China State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing100081 China HEDPS Center for Applied Physics and Technology College of Engineering Peking University Beijing100871 China Key Laboratory of Transient Physics Nanjing University of Science and Technology Nanjing210094 China School of Mechanics and Safety Engineering Zhengzhou University Zhengzhou450001 China

The two-dimensional Rayleigh-Taylor Instability (RTI) in compressible flow with inter-molecular interactions is probed via the Discrete Boltzmann Method (DBM). The effects of interfacial tension, viscosity and heat conduction are investigated. It is found that the influences of interfacial tension on the perturbation amplitude, bubble velocity, and two kinds of entropy production rates all show differences at different stages of RTI evolution. It inhibits the RTI evolution at the bubble acceleration stage, while at the asymptotic velocity stage, it first promotes and then inhibits the RTI evolution. Viscosity and heat conduction inhibit the RTI evolution. Viscosity shows a suppressive effect on the entropy generation rate related to heat flow at the early stage but a first promotive and then suppressive effect on the entropy generation rate related to heat flow at a later stage. Heat conduction shows a promotive effect on the entropy generation rate related to heat flow at an early stage. Still, it offers a first promotive and then suppressive effect on the entropy generation rate related to heat flow at a later stage. By introducing the morphological boundary length, we find that the stage of exponential growth of the interface length with time corresponds to the bubble acceleration stage. The first maximum point of the interface length change rate and the first maximum point of the change rate of the entropy generation rate related to viscous stress can be used as a criterion for RTI to enter the asymptotic velocity stage. Copyright © 2022, The Authors. All rights reserved.

关键词： Viscosity

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