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Nondestructive measurement of the thickness and refractive index of polymer thin films using a single-frequency terahertz Mueller matrix ellipsometry

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Optics Express 2025年第9期33卷 19605-19615页

作者： Yang, Haoming Liu, Defeng Huang, Qian Ming, Ziwei Yang, Zhengang Wang, Kejia Wuhan National Laboratory for Optoelectronics School of Optical and Electronic Information Optics Valley Laboratory Huazhong University of Science and Technology Wuhan430074 China AVIC Beijing Changcheng Aeronautical Measurement and Control Technology Research Institute Beijing101111 China

Terahertz Mueller matrix ellipsometry is a nondestructive technique based on terahertz waves that can measure film thickness and optical constants with high accuracy. We propose a single-frequency terahertz Mueller matrix ellipsometry based on a dual rotating compensator configuration, which utilizes terahertz waves to achieve high-precision nondestructive measurements of the thickness and refractive index of polymer films. The system realizes the fully polarized incidence of the terahertz beam by rotating the compensator, and establishes a complete polarization measurement scheme by measuring the outgoing light intensity of the two compensators at different angles. Based on the coherent light scattering model, we developed a corresponding data processing algorithm and realized the simultaneous and accurate determination of the film thickness and refractive index through the extraction and inverse calculation of the full Mueller matrix elements. The experimental results show that the system has excellent measurement accuracy and reliability. This research opens up what we believe to be a new research pathway for the characterization and detection of thin film materials, which has an important application value in the field of material science and industrial testing. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Materials testing

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Terahertz time-of-flight tomography algorithm for different curvature samples

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Optics Express 2025年第7期33卷 15095-15109页

作者： Zhou, Yu Li, Quanyong Cui, Zongyu Zhang, Jiyang Ren, Jiaojiao Zhang, Dandan Gu, Jian Li, Haoxiang Lin, Zihao Key Laboratory of Optoelectronic Measurement and Control and Optical Information Transmission Technology Ministry of Education Changchun University of Science and Technology Changchun130022 China School of Optoelectronic Engineering Changchun University of Science and Technology Changchun130022 China Zhongshan Research Institute Changchun University of Science and Technology Zhongshan528403 China

Traditional guide rail-based terahertz reflection tomography works well with planar samples and complements transmission tomography. Most imaging methods perform effectively with plane-like or simple curvature samples. However, these methods are ineffective for complex shapes due to the challenges of dealing with internal corrections and stitching errors. To address the above issues, terahertz time-of-flight tomography is applied to the prepared samples with abnormal curvature using a rotating scanning array and "point cloud splicing" method. This approach enables comprehensive sample information collection and resolves the inner layer point cloud position correction challenge. A radial distance point cloud down-sampling method is proposed to reduce the impact of overlapping point clouds on reconstruction accuracy. After down-sampling, the outer layer reconstruction error reduces to 0.22%. Poisson surface reconstruction further enhances the intuitiveness of imaging results, and the reconstruction accuracy is 0.01 mm. This study broadens the application of terahertz time-of-flight tomography and offers a different approach for reflection tomography. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Surface reconstruction

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Nonlinear correction of terahertz FMCW based on time-domain phase compensation

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Optics Letters 2025年第8期50卷 2630-2633页

作者： Liang, Bin Shen, Sishi Wang, Tianyi Wang, Yue Hao, Congjing Liu, Defeng Liu, Jinsong Wang, Kejia Yang, Zhengang Wuhan National Laboratory for Optoelectronics School of Optical and Electronic Information Optics Valley Laboratory Huazhong University of Science and Technology Wuhan430074 China Huazhong Institute of Electro-Optics Wuhan430299 China AVIC Beijing Changcheng Aeronautical Measurement and Control Technology Research Institute Beijing101111 China

Terahertz frequency-modulated continuous-wave (THz FMCW) technology has become a widely used nondestructive testing tool due to its imaging and detection advantages. Nonlinearity is one of the most common problems with FMCW technology. This is due to the inability to maintain strict linearity during the high-frequency sweep process, resulting in multiple frequencies in the calculated intermediate frequency (IF) signal. This reduces the detection capability of the system, as the effective frequencies are swamped. This paper proposes a nonlinear correction method based on the time-domain phase compensation technique. The causes of nonlinear distortion are analyzed, and the corrected signal is obtained after phase compensation of the instantaneous time-domain signal. Experimental results obtained froman actual terahertz imaging system proved the effectiveness of the proposed method, achieving precise positioning of three-dimensional objects. The range resolution was improved by an order of magnitude, reaching the theoretical resolution of the experimental system. The method improves the detection accuracy of the system without the need for additional equipment. © 2025 Optica Publishing Group.

关键词： Terahertz waves

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Immersive Virtual Reality Cruise Garden Relaxation Train: A Novel BCI Platform for Depression 6th

Immersive Virtual Reality Cruise Garden Relaxation Train: A ...

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6th International Conference on Biomedical and Health Informatics, ICBHI 2024

作者： Tsai, Shu-Hui Chao, Chih-Chiang Lin, Yue-Der Kuo, Chin-Jung Dong, Shu-Ping Liu, Chun-Yuan Ko, Hsin-Yi Wang, Jenn-Hann Liu, Ching Hsiu Service Systems Technology Center Industrial Technology Research Institute Hsin-Chu Taiwan Center for Measurement Standards Industrial Technology Research Institute Hsin-Chu Taiwan Department of Automatic Control Engineering Feng-Chia University Taichung Taiwan Central Division Industrial Technology Research Institute Hsin-Chu Taiwan Mackay Memorial Hospital Hsin-Chu Taiwan

ISBN: (纸本)9783031863226

The staggering global prevalence of depression extends to Taiwan, where approximately 8.9% of the population exhibits symptoms of depression, affecting around 2 million individuals, with 1.25 million classified as severe cases. Depression exerts profound impacts on both socioeconomic and health aspects, ranking as one of the leading causes of disability and closely linked with dementia. Over 70% of suicides involve individuals with depression, and those with depression face significantly higher suicide risks compared to the general population. Of particular concern is the higher-than-expected prevalence of depression, which, if left untreated, may escalate suicide risks. research indicates that individuals with depression display unstable and imbalanced brainwave patterns, characterized by a lack of normal baseline brainwaves and elevated slow waves. While the commonly used repeated transcranial magnetic stimulation (rTMS) therapy can modulate brainwaves, the treatment is costly and often associated with high relapse rates, imposing a significant burden on patients. Recent studies reveal that potential depression sufferers commonly experience brainwave dysregulation and neuro-immune disruption, emphasizing the need for personalized emotional, brainwave, and autonomic nervous system regulation, along with community support. This study aims to integrate elements such as "Brainwave Entrainment with Schumann Resonance and Autonomic Nervous System Feedback Device", "Light Therapy Device", and "Garden Train-Style Anxiety-Relief Environment" to provide simulated natural environment brainwave and autonomic nervous system regulation, as well as light therapy. Additionally, it involves designing a safe "Garden Train" virtual reality environment to offer a secure and comforting anxiety-relief space for individuals at risk or suffering from depression, as well as caregivers. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Electrotherapeutics

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A Self-Test Method for MEMS Gyroscope With Equivalent Inertial Force

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IEEE Transactions on Instrumentation and measurement 2025年 74卷

作者： Zhou, Rui Cui, Rang Shen, Chong Shi, Yunbo Yu, Jingfeng Ren, Yanchao Cao, Huiliang North University of China Science and Technology on Electronic Test and Measurement Laboratory School of Instrument and Electronics Taiyuan030051 China Quanzhou Yunjian Measurement Control and Perception Technology Innovation Research Institute Quanzhou362000 China

This article introduces a self-test approach for micro-electromechanical system (MEMS) vibrating gyroscopes based on the concept of equivalent inertial force. By applying electrostatic signals to the feedback electrode, it is possible to simulate the inertial force input, enabling measurement of the gyroscope scale factor (SF) without reliance on physical testing equipment. This article presents the operational principle of equivalent inertial force, establishes the correlation between equivalent inertial force and angular velocity through derivation, and accomplishes the calibration of this relationship across a broad temperature range using quadrature feedback forces. In contrast to traditional methods, this approach facilitates direct measurement of the SF of the gyroscope and compensates for variations in the SF induced by alterations in the temperature and environmental conditions. The efficacy of the proposed approach was validated in a comparative experiment on a ring resonator gyroscope. In the open-loop mode, the average calibration error of the SF of the equivalent inertial force method and the turntable method is 5.608%. The long-term self-test repeatability is 1781.2 ppm. Furthermore, the SF self-compensation of the gyroscope within the temperature range of - 20°C to + 40°C was achieved using the self-test results. The temperature sensitivity of the SF before and after compensation changed from 6689.7 ppm/°C to 318.6 ppm/°C, which was reduced by 20×. © 1963-2012 IEEE.

关键词： Gyroscopes

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Thermal constraint control of reversible solid oxide cell for optimal system efficiency

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International Journal of Hydrogen Energy 2025年 134卷 198-211页

作者： Xu, Yuanwu Yin, Jie Wang, Jingjing Wu, Xiao-long Peng, Jingxuan Tang, Ruifeng Zou, Suhang Fu, Xiaowei Li, Xi School of Artificial Intelligence and Automation Wuhan University of Science and Technology Hubei Wuhan430081 China School of Artificial Intelligence and Automation Key Laboratory of Image Processing and Intelligent Control of Education Ministry Huazhong University of Science and Technology Hubei Wuhan430074 China School of Information Engineering Nanchang University Jiangxi Nanchang330031 China School of Electrical and Electronic Engineering Nanyang Technological University 639798 Singapore China-Poland Belt and Road Joint Laboratory on Measurement and Control Technology Huazhong University of Science and Technology Hubei Wuhan430074 China Shenzhen Huazhong University of Science and Technology Research Institute Shenzhen518055 China

Reversible solid oxide cell (RSOC) demonstrates considerable promise in multimodal energy conversion architectures, particularly as a technology for hydrogen-based energy storage systems. Nevertheless, under dynamic operating regimes with time-varying current inputs, realizing time-efficient and reliable transitions to steady-state operation remains difficult. This difficulty arises from the intricate coupling of thermal, electrical, and gaseous processes within the RSOC system. This study aims to address these challenges by developing a 5 kW mathematical model of the RSOC system. The proposed model enables systematic investigation of thermal safety issues arising during current switching operations while introducing a thermal constraint control strategy to enhance both system efficiency and thermal safety performance. This efficiency-driven study employs the Grid Search algorithm to identify optimal steady-state operating points for the RSOC system, ensuring strict adherence to safety constraints across varying current inputs. Furthermore, by integrating the pre-identified optimal operating points as feedforward control with Model Predictive control (MPC)-based feedback correction, this hybrid strategy effectively mitigates stack temperature gradient overshoot while synchronously ensuring optimal system efficiency throughout current transition processes. Under simulated variable current inputs, the proposed RSOC system model and control strategy demonstrate the capability to constrain stack temperature gradient overshoot within 2.3K while enhancing transient efficiency by 5 %–8 %, achieving a peak system efficiency of 85 %. It provides a novel methodology for safe and efficient working with intermittent renewable energy. © 2025 Hydrogen Energy Publications LLC

关键词： Thermal variables control

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Coordinated and Optimized Scheduling of Integrated Energy System Based on Improved Beluga Algorithm 9th

Coordinated and Optimized Scheduling of Integrated Energy Sy...

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9th Purple Mountain Form on Smart Grid Protection and control, PMF 2024

作者： Zhang, Zhuanqin Wang, Hui Xiao, Jieping Zhou, Weichao Zhao, Zijun Guan, Baojin School of Electrical Engineering and Information Technology Changchun Institute of Technology Changchun130012 China National Local Joint Engineering Research Center for Smart Distribution Grid Measurement and Control with Safety Operation Technology Changchun130012 China State Grid Jilin Electric Power Co. Ltd. Yanbian Power Supply Company Yanbian133000 China Jilin Institute of Chemical Technology Jilin132022 China

ISBN: (纸本)9789819616701

In order to solve the problems of low energy utilization, high carbon emission and poor economic benefit of integrated energy system, this paper proposes an improved beluga algorithm to realize coordinated and optimal dispatching of integrated energy system. Firstly, the operation framework of the integrated energy system is built, and the two-stage electricity-to-gas model and carbon trading mechanism model were constructed. Secondly, the improved Moby Dick algorithm is used to optimize the comprehensive energy system. Finally, the matlab2021a+gurobi solution environment is used to verify the solution. The results show that the proposed algorithm can effectively improve the energy utilization rate of the system, while ensuring the low carbon and economy of the integrated energy system. © State Grid Electric Power 2025.

关键词： Low emission

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MorNet: Asymmetric UNet-like Network with Morphological Opening and Closing for Image Segmentation 17th

MorNet: Asymmetric UNet-like Network with Morphological Open...

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17th International Conference on Intelligent Robotics and Applications, ICIRA 2024

作者： Li, Meng Yun, Juntong Jiang, Du Tao, Bo Li, Gongfa Liu, Rong Liu, Ying Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education Wuhan University of Science and Technology Wuhan430081 China Research Center for Biomimetic Robot and Intelligent Measurement and Control Wuhan University of Science and Technology Wuhan430081 China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and Technology Wuhan430081 China Precision Manufacturing Research Institute Wuhan University of Science and Technology Wuhan430081 China School of Medicine Wuhan University of Science and Technology No. 1 Huangjia Lake University Town Wuhan430065 China School of Mechanical Engineering Hubei Engineering University Xiaogan432000 China

ISBN: (纸本)9789819607761

Image segmentation plays a crucial role in target recognition as it provides an essential prerequisite for identifying targets. However, UNet cannot acquire comprehensive information about the image, which limits its ability to effectively segment small and discrete objects. A new network structure, called MorNet, is proposed. It applies dilation and erosion operations in morphological opening and closing for connected and discrete region segmentation. MorNet effectively integrates global segmentation images, emphasizing small and discrete area segmentation and enhancing the segmentation of large continuous areas. This method enhances the understanding of the location of organs and diseased sites, enabling accurate segmentation. A side-out (SO) monitoring mechanism is introduced into the decoder to provide monitoring information for the original image and the predicted results. Compared with current UNet-like networks, our proposed method achieved the highest Dice scores (96.4635%, 94.0514%, 94.3444%) and PPV scores (94.2226%, 90.2361%, 91.5582%) for liver tumor, brain tumor, and liver segmentation tasks, respectively. The experimental results show that MorNet successfully combines the segmentation of connected and discrete regions. MorNet locates organs and lesions more accurately than current state-of-the-art medical image segmentation models. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Image segmentation

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Density characterization of hydrogen-blended natural gas system by a single-sinker densimeter for future hydrogen economy

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International Journal of Hydrogen Energy 2025年 135卷 507-514页

作者： Lin, Qingjin Zhang, Pu Zhou, Li Zhang, Peiying Sheng, Bowen Gong, Maoqiong Research Institute of Natural Gas Technology PetroChina Southwest Oil & Gasfield Company Sichuan Chengdu610213 China Key Laboratory of Natural Gas Quality Control and Energy Measurement State Administration for Market Regulation Sichuan Chengdu610213 China Key Laboratory of Natural Gas Quality Control and Energy Measurement CNPC Sichuan Chengdu610213 China State Key Laboratory of Cryogenic Science and Technology Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing100190 China

Hydrogen-blended natural gas (HNG) has emerged as a promising energy carrier for hydrogen transportation and carbon emission reduction. Precise determination of thermophysical properties in HNG mixtures is critical for optimizing the design of storage infrastructure, pipeline networks, and end-use applications. This work investigated the density of Chinese natural gas blended with hydrogen (3–20 %) using a single-sinker densimeter across temperatures (253.15 K–350.15 K), with pressures up to 10 MPa. Experimental results have been compared with predictions from three equations of state (EoSs), including GERG-2008, AGA8-DC92, and PR. The GERG-2008 and AGA8-DC92 EoSs remained better than 0.10 % and 0.11 % of average absolute relative deviation (AARD), respectively, and the AARD of PR EoS exceeds 2.13 %. It demonstrated superior accuracy of GERG-2008 and AGA8-DC92 EoSs for the hydrogen-blended natural gas mixture with 3–20 % H2 compared to the PR EoS. However, GERG-2008 EoS exhibited a relative deviation of 0.16 % at 3 MPa. Pressure dependence analysis revealed no similar trend in relative deviations for all mixtures as increasing pressure. Blending hydrogen resulted in a larger discreteness of the relative deviation at different temperatures between the calculated values from the GERG-2008 and AGA8-DC92 EoSs and the experimental ones. Thus, the mixing rule model in the equations of state may be improved while applied to hydrogen-blended natural gas mixtures. © 2025 Hydrogen Energy Publications LLC

关键词： Natural gas transportation

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An enhanced nonlinear fatigue cumulative damage model based on toughness exhaustion and strength degradation

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International Journal of Fatigue 2025年 198卷

作者： Yu, Yifan Wang, Liyong Wu, Jianpeng Chang, Shuyuan Zhang, Ximing Key Laboratory of Advanced Manufacturing Technology Beijing University of Technology Beijing100124 China Key Laboratory of Modern Measurement and Control Technology in Ministry of Education Beijing Information Science and Technology University Beijing100192 China Science and Technology on Vehicle Transmission Laboratory China North Vehicle Research Institute Beijing100072 China

Accurate prediction of fatigue life under variable amplitude (VA) loading remains fundamentally challenged by load-sequence-dependent damage accumulation in metallic structures. This study establishes a nonlinear cumulative damage model integrating toughness exhaustion and strength degradation mechanisms through damage equivalence principles. Multi-level VA experiments on carbon steel, alloy steel, and aerospace aluminum alloys demonstrate that the proposed model reduces life prediction errors to 6.53% (5-level) and 9.43% (8-level), achieving 93.94% and 94.79% accuracy improvement versus the Palmgren-Miner method. Statistical evaluations reveal dominant control of two key factors: material ultimate tensile strength (UTS) and stress amplitude differential between successive cycles. These advancements provide validated engineering tools for durability assessment of aero-engine components and military vehicle systems experiencing complex mission profiles. © 2025 Elsevier Ltd

关键词： Aluminum alloys

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