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Spectral asymmetry effect in terahertz generation by two-color ionizing femtosecond pulses

Physical Review A 2025年第2期111卷 023508-023508页

作者： Zhiwen Zhang Vasily A. Kostin Alexander A. Silaev Zefu Liu Shixiang Wang Chenhui Lu Zhengquan Fan Yi Liu Shanghai Key Lab of Modern Optical System University of Shanghai for Science and Technology Shanghai 200093 China Gaponov-Grekhov Institute of Applied Physics of the Russian Academy of Sciences Nizhny Novgorod 603950 Russia Department of Control Theory Lobachevsky State University of Nizhny Novgorod Nizhny Novgorod 603022 Russia Department of Electrodynamics Lobachevsky State University of Nizhny Novgorod Nizhny Novgorod 603022 Russia School of Mechanical and Automotive Engineering Shanghai University of Engineering Science Shanghai 201620 China CAS Center for Excellence in Ultra-Intense Laser Science Shanghai 201800 China

Ultrabroadband intense terahertz (THz) radiation generated by two-color femtosecond pulses is a promising tool for applications in many areas involving linear and nonlinear terahertz spectroscopy and light-matter interactions. The essential challenge is to understand and control the THz spectrum in order to optimize it for specific applications. Here we study the frequency-dependent modulation of the THz spectrum with the relative phase between the second-harmonic and fundamental-field components of the linearly polarized femtosecond pulse. Analytical consideration reveals the physical reason for the suppression of the spectral modulation, which is local (induced by the local ionization dynamics and electron motion and not related to propagation effects such as phase slippage) and coherent (associated only with the phase-dependent coherent THz waveforms). The spectral modulation is sensitive to the frequency detuning, both its absolute value and the sign. Having this asymmetric dependence on the detuning, the suppressed modulation can be observed even in commensurate two-color pulses with the effect enhanced additionally by the ionization blueshift. The theoretical findings are confirmed by the experiment, where we employed chirped two-color pulses with a variable time delay between their components, effectively enabling a scan over the detuning. The obtained results show that not only the THz yield but also the spectral shape can be effectively controlled by the relative phase and may be very sensitive to a small frequency detuning arising naturally during two-color pulse propagation.

关键词： Terahertz spectroscopy

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A knowledge-based express model of operational plan containing uncertainties 20

A knowledge-based express model of operational plan containi...

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2nd World Symposium on Software engineering, WSSE 2020

作者： Jin, Xin Wang, Xinnian Yu, Yan Science and Technology on Information System Engineering Laboratory Nanjing Research Institute of Electronic Engineering Nanjing Jiangsu China Science and Technology on Information System Engineering Laboratory Beijing Research Institute of Control and Electronic Technology Beijing China

ISBN: (纸本)9781450387873

Under the new confrontational mode of "Multi-Domain Operations", "change"becomes the key to victory. Uncertainty becomes an important challenge to operational command decision making. Traditional operational plans are made according to deterministic assumptions and has very limited ability to adapt to changes. Only human can adapt according to his own understanding to plans. This study proposes a knowledge-based express model of operational plan containing uncertainties. It can formally describe operational plans with uncertain starting time, optional strategies and dynamic calculated parameters, and can be executed by machine. It may be used in wargames, autonomous action monitoring, and other intelligent applications. © 2020 ACM.

关键词： Knowledge representation

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controlling the depth of a gliding robotic dolphin using dual motion control modes

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science China(Information sciences) 2020年第9期63卷 217-230页

作者： Jian WANG Zhengxing WU Min TAN Junzhi YU State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory for Turbulence and Complex System Department of Mechanics and Engineering ScienceBIC-ESAT College of Engineering Peking University

This paper investigates the performance of the dual mode, namely flipper mode and central pattern generator(CPG) mode, for controlling the depth of a gliding robotic dolphin. Subsequent to considering the errors in dynamic models, we propose a depth control system that combines the line-of-sight(LOS)method with an adaptive control approach(ACA) to deal with uncertainties in the model parameters. First,we establish a full-state dynamic model to conduct simulations and optimize the parameters used in later aquatic experiments. Then, we use the LOS method to transform the control target from the depth to the pitch angle and employ the ACA to calculate the control signal. In particular, we optimize the ACA’s control parameters using simulations based on our dynamic model. Finally, our simulated and experimental results demonstrate not only that we can successfully control the robotic dolphin’s depth, but also that its performance was better than that of the CPG-based control, thus indicating that we can achieve three-dimensional motion by combining flipper-based and CPG-based control. The results of this study suggest valuable ideas for practical applications of gliding robotic dolphins.

关键词： gliding robotic dolphin depth control dual motion adaptive control approach

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Safe Tracker: A Robust Aerial system for Safe Tracking in Cluttered Environments

Safe Tracker: A Robust Aerial System for Safe Tracking in Cl...

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Chinese control Conference (CCC)

作者： Yulin Hui Bailing Tian Xuewei Zhang Hanchen Lu Hongming Shen School of Electrical and Information Engineering Tianjin University Tianjin P. R. China Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory Beijing Electro-Mechanical Engineering Institute Beijing P. R. China

This paper proposes Safe Tracker, an autonomous aerial tracking framework based on vision sensor that can deal with challenging tracking missions and guarantee safety and visibility. Firstly, a RGB-D sensor based segmentation method is employed to locate the target in real-time. Then target motion is predicted for a short time horizon, based on which a heuristic path searching method is applied to generate an occlusion-free path. Finally, particular formulations to balance visibility and safety are designed, and an effective non-linear trajectory optimization method enables to generate an optimal tracking trajectory. Autonomous aerial tracking experiments using a vision sensor are conducted to demonstrate the effectiveness of the proposed Safe Tracker in a challenging cluttered forest and a room full of sharp turns using Gazebo. Benchmark comparisons validate that our method tracks more safely and robustly than the state-of-art method.

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The Mechanism of P-Nitrophenol Degradation by Dissolved Organic Matter Derived from Biochar

SSRN

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SSRN 2022年

作者： Zhang, Peng Zhang, Peng Jim Feng, Shihui Li, Hao Li, Jing Du, Wei Duan, Wenyan Li, Xiaohan Zhang, Chan Li, Hanxue Song, Shuangjie Pan, Bo Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control Faculty of Environmental Science & Engineering Kunming University of Science & Technology Kunming650500 China Institute of Surface-Earth System Science School of Earth System Science Tianjin University Tianjin300072 China

Biochar exhibited excellent performance in the areas of pollutant removal, carbon sequestration, and environmental remediation. Recently, p-nitrophenol (PNP), a common organic pollutant in the environment, was reported to be degraded by biochar. Although the degradation mechanism of PNP by biochar has been explored, the role of biochar-derived dissolved organic matter (BDOM) in PNP degradation has not been investigated before. Two BDOM samples were prepared in this study, and the PNP removal performance were analyzed. The results showed that, BDOM5 (prepared at 500°C) exhibited higher PNP removal capability than BDOM7 (prepared at 700°C). The PNP removal capacities of BDOM5 and BDOM7 reached 1.43 and 0.63 mg/mg, respectively. GC-MS analysis showed that both the oxidation and reduction degradation processes existed in the PNP degradation by BDOM. Hydroxyl radicals (•OH) played a critical role in the PNP degradation by BDOM. This study shed light on the phenomenon of the PNP degradation by BDOM and promoted the accurate environmental impact assessment of biochar in the application. © 2022, The Authors. All rights reserved.

关键词： Organic pollutants

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原子级化学反应促进可弱光探测有机光电倍增探测器的外量子效率超过10^(8)%

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science Bulletin 2023年第9期68卷 928-937,M0004页

作者：石林林朱益志李国辉冀婷王文艳张叶吴宇坤郝玉英王开鹰袁俊邹应萍 Beng S.Ong 朱福荣崔艳霞 College of Optoelectronics Key Laboratory of Interface Science and Engineering in Advanced MaterialsKey Laboratory of Advanced Transducers and Intlligent Control System of Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030032China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Department of Physics Research Centre of Excellence for Organic ElectronicsInstitute of Advanced MaterialsHong Kong Baptist UniversityHong KongChina Department of MicrosystemsUniversity of South-Eastern NorwayHorten 3184Norway College of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China

外量子效率远大于100%、低成本、溶液法制备的倍增型有机光电探测器(PM-OPDs)引起广泛关注.但该类器件因阳极欧姆接触带来暗电流的恶化,使其弱光探测并不理想.基于此,本文提出了原子级化学反应改善PM-OPDs暗电流及弱光探测策略,进而带... 详细信息

外量子效率远大于100%、低成本、溶液法制备的倍增型有机光电探测器(PM-OPDs)引起广泛关注.但该类器件因阳极欧姆接触带来暗电流的恶化,使其弱光探测并不理想.基于此,本文提出了原子级化学反应改善PM-OPDs暗电流及弱光探测策略,进而带来器件综合性能的显著提升.具体地,本文利用原子层沉积技术在空穴传输层PEDOT:PSS与活性层P3HT:PC71BM(100:1)之间引入0.8 nm厚的Al_(2)O_(3)界面层,通过对薄膜拉曼、XPS及FT-IR性能进行表征,发现原子级厚度的Al_(2)O_(3)可与PEDOT:PSS的化学基团发生反应,调节PEDOT:PSS的功函数,进而在阳极一侧形成肖特基接触.通过与阴极肖特基接触协同,器件在保持高倍增行为的同时,暗电流显著降低.最终,器件的弱光探测性能有所改善,相比于标准器件(可探测64 nW/cm^(2)弱光),Al_(2)O_(3)修饰器件可探测低至2.5 nW/cm^(2)的弱光,且相应的外量子效率和响应率分别达到4.31×10^(8)%,1.85×10^(6)A/W,达到目前报道PM-OPDs的最优值.此策略在新型柔性电子产品及医学成像领域具有很好的应用前景.

关键词：外量子效率肖特基接触弱光探测原子级暗电流柔性电子欧姆接触空穴传输层

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A New Method to Estimate the Severity of Interturn Short-Circuit Fault for PMSM

A New Method to Estimate the Severity of Interturn Short-Cir...

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2022 IEEE International Conference on Power systems and Electrical Technology, PSET 2022

作者： Zeng, Zhaofei Zhang, Man Chen, Luan Huang, Qi Sun, Ding University of Electron Ic Science and Technology of China Key Laboratory of Wi De-area Measurement and Control on Power System of Sichuan Province Chengdu611731 China University of Electronic Science and Technology of China Chengdu611731 China Institute of Electronic and Information Engineering of Uestc in Guangdong Uestc in Guangdong Dongguan523808 China Chengdu Univer Sity of Technology Chengdu610095 China

ISBN: (纸本)9781665489157

This paper proposes a new method to determine the number of shorted turns for permanent magnet synchronous motor (PMSM). At first, the equivalent circuit model of PMSM under both normal condition and inter-turn short-circuit (ITSC) fault are presented. Then, the procedure to estimate the severity of ITSC in PMSM is introduced. In detailed, the stator winding of PMSM at standstill is excited by a low AC voltage, the corresponding current can be measured including its amplitude and phase, finally, the severity estimation indicator is established based on the electromagnetic parameters, including amplitude and phase of voltage and current, phase inductance and resistance. The effectiveness of the proposed method is verified by some simulations, which illustrates that the proposed method have good accuracy in the number of shorted turns detection in the range from the fault-free state to the full-winding fault state. The method proposed in this paper can be directly implemented without installing complex equipment and additional sensors on the motor, and it has utility value in the maintenance of PMSM. © 2022 IEEE.

关键词： Permanent magnets

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Achieving Peta-Ohm Resistance for Semi-Insulating 4H-SiC Devices by Atomic Layer Deposition

arXiv

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arXiv 2024年

作者： Xi, Yuying Li, Helios Y. Li, Guohui Su, Qingmei Mao, Kaili Xu, Bingshe Hao, Yuying Fang, Nicholas X. Cui, Yanxia College of Electronic Information and Optical Engineering Key Lab of Interface Science and Engineering in Advanced Materials Key Lab of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan University of Technology Taiyuan030024 China Department of Mechanical Engineering University of Hong Kong Hong Kong999077 Hong Kong School of Materials Science and Engineering Materials Institute of Atomic and Molecular Science Shaanxi University of Science and Technology Xi’an710021 China Shanxi Semisic Crystal Co. Ltd. Taiyuan030000 China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan030032 China

Growing demands for precise current measurements, such as atto-ampere-level measurement of cross-cellular biological current transduction, have spotlighted a pressing need for low-noise resistors with ultra-high resistance immune to voltage fluctuations. Traditional semi-insulating materials, however, struggle to provide consistent resistance across varying voltages. To bridge this gap, we introduce a design that integrates semi-insulating 4H-SiC with atomic-level metal oxide interlayers and electrodes. The strategic adjustment of surface states via atomic-scale metal oxide layers optimizes the work functions on 4H-SiC surfaces, validated through density functional theory simulations. This design transcends conventional limitations, establishing an ideal Ohmic behavior and maintains Peta-Ohm-level resistance, unaffected by voltage variations. These on-chip devices with fine-tuned resistance are compatible with integrated circuit manufacturing processes, making them ideally suited for applications in precision electronics. © 2024, CC BY-NC-ND.

关键词： Silicon carbide

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Design of a Capsule Robot system for Gastric Hemorrhage Detection using Luminol 20

Design of a Capsule Robot System for Gastric Hemorrhage Dete...

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20th IEEE International Conference on Mechatronics and Automation, ICMA 2023

作者： Mao, Yuchen Guo, Jian Guo, Shuxiang Fu, Qiang Tianjin University of Technology Tianjin Key Laboratory for Control Theory & Application Complicated Systems Intelligent Robot Laboratory School of Electrical Engineering and Automation Binshui Xidao Extension 391 Tianjin300384 China Shenzhen Institute of Advanced Biomedical Robot Co. Ltd No.12 Ganli Sixth Road Jihua Street Longgang District Shenzhen518100 China Key Laboratory of Convergence Medical Engineering System and Healthcare Technology The Ministry of Industry and Information Technology School of Life Science Beijing Institute of Technology No.5 Zhongguancun South Street Beijing100081 China

ISBN: (纸本)9798350320831

Gastric hemorrhage in upper gastrointestinal bleeding is an obvious indicator of deteriorating gastric disease. This paper proposes a capsule robot system for detecting bleeding in the stomach. The patient ingests a capsule robot containing luminol reagent, which detects bleeding in the stomach via chemiluminescence. The MCU receives the optical sensor signal, and the data is transmitted via radio frequency. The external lower computer receives and forwards the data to the upper computer for processing and display. The data is used to determine the presence and amount of stomach bleeding. Chemiluminescence is an excellent sensor, requiring no external energy supply, and demonstrating excellent sensitivity and selectivity. Combining chemical and electronic sensors presents opportunities for further development. Capsule robot detection reduces the discomfort and risk of secondary injury associated with traditional endoscopy. This paper establishes an experimental platform using porcine blood to simulate human blood, demonstrating the feasibility of the system. © 2023 IEEE.

关键词： Chemiluminescence

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Dynamic area coverage for Multi-USV with fully connected constraint based on game theory

Dynamic area coverage for Multi-USV with fully connected con...

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Chinese Automation Congress (CAC)

作者： Xiao Han Huan Chen Yufeng Gao Guangfu Ma Shuanghong Wu Wenxin Hao Department of Control Science and Engineering Harbin Institute of Technology Harbin China China Ship Development and Design Center Wuhan China The Beijing Institute of Spacecraft System Engineering China Academy of Space Technology Beijing China

This paper proposes a novel method to solve the problem of regional surveys on the ocean in a complex environment. In order to solve this challenging regional survey problem considering fully connected, a new method combined artificial potential field and game theory is designed to maximize the coverage ratio. This paper gives the mathematical model of information transfer between two unmanned surface vehicles(USVs), and then the motion strategy of USVs is given based on the idea of game theory. The area coverage task of the multi-USV system is realized by a control method similar to the artificial potential field method.

关键词： Sea surface Automation Heuristic algorithms Dynamics control systems Mathematical models Game theory

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