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Research on the Theoretical Steady-State Error of Direct Current Comparator

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Research on the Theoretical Steady-State Error of Direct Cur...

International Conference on Electronic measurement and Instruments, ICEMI

作者： Liren Zhou Li Zhu Ji Geng Qin Yi Pan Yang Shanghai Key Laboratory of Online Testing and Control Technology Shanghai Institute of Measurement and Testing Technology Shanghai China

ISBN: (纸本)9781665444927

In virtue of modern control theory, combining with the analysis of structure and principle of direct current comparator (DCC), relative error formula of direct current ratio was derived to theoretically analyze the steady state value. Resolve each part of transfer function and then compound the closed-loop transfer function. Employ Nyquist stability criterion to judge the system stability; establish the closed-loop transfer characteristic simulation model; take unit ampere turn value as example and the simulation result was analyzed. The results showed that the secondary side fast tracked the primary side signal and output signal smoothly, without obvious transition appearance such as overshoot and oscillation, according with the principle of DCC. The steady-state error of direct current ratio is 2.5×10 −8 , consisting with the derived theoretical value, meeting the expected design requirements.

关键词： Analytical models Negative feedback Simulation Stability criteria Transfer functions Software Steady-state

Biomass Ppower generation: A pathway to carbon neutrality

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Science of the Total Environment 2024年 933卷

作者： Du, Wei Cui, Zhanpeng Wang, Jinze Qin, Yiming Ye, Jianhuai Lin, Nan Chen, Yuanchen Duan, Wenyan Chang, Zhaofeng Li, Hao Zhang, Peng 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 Key Laboratory for Earth Surface Processes College of Urban and Environmental Sciences Peking University Beijing100871 China School of Energy and Environment City University of Hong Kong SAR 999077 Hong Kong Shenzhen Key Laboratory of Precision Measurement and Early Warning Technology for Urban Environmental Health Risks School of Environmental Science and Engineering Southern University of Science and Technology Guangdong Shenzhen China Department of Environmental Health School of Public Health Shanghai Jiao Tong University Shanghai200025 China Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province College of Environment Zhejiang University of Technology Zhejiang Hangzhou310032 China

In light of the pressing need to reduce carbon emissions, the biomass power generation industry has gained significant attention and has increasingly become a crucial focus in China. However, there are still considerable gaps in the historical background, status, and prospects of biomass power generation. Herein, the historical and current status of biomass power generation in China are systematically reviewed, with a particular emphasis on supportive policies, environmental impacts, and future projections. By 2022, the newly installed capacity for biomass power generation reached 3.34 MW with a total installed capacity of 41 MW. The power produced from biomass power generation is 182.4 billion kWh in China. The total installed capacity and generated power in 2022 were 1652 and 1139 folds higher than in 2006 when the first biomass generation plant was established. However, disparities in the distribution of biomass resources and power generation were observed. key drivers of the industry development include tax, finance, and subsidy policies. Under the implementation of the 14th Five-Year Plan for renewable energy development and the goal of carbon neutrality, biomass power generation may achieve great success through more targeted policy support and advanced technologies that reduce air pollutant emissions. If combined with Bioenergy with Carbon Capture and Storage (BECCS) technology, biomass power generation will make its contribution to carbon neutrality in China. © 2024 Elsevier B.V.

关键词： Greenhouse gases

Power Uncertainty Evaluation of Microwave Digestion System based on Monte-Carlo Method

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Power Uncertainty Evaluation of Microwave Digestion System b...

IEEE Advanced Information technology, Electronic and Automation control Conference (IAEAC)

作者： Tianlei Xiao Shuhui Wang Zhichun Xiong Shanghai Institute of Measurement and Testing Technology Shanghai China Key laboratory of online testing and control technology of Shanghai Shanghai China

ISBN: (数字)9781728180281

ISBN: (纸本)9781728180298

The article implemented an uncertainty evaluation method for output power of microwave digestion system, based on the adaptive Monte Carlo method and the correlation of inputs. The result is compared with that obtained by GUM method. By using Kolmogorov-Smirnov and Normal probability method, the probability distribution of the output has deviated from normal distribution in a certain interval. The Result of GUM method is not validated, and MCM method is proved to be faster and more efficient in the case of complex models and correlative cases.

关键词： Microwave measurement Uncertainty Monte Carlo methods Correlation Sensitivity Power measurement Probability distribution

TEMPORAL-SPATIAL REPRESENTATION LEARNING TRANSFORMER FOR EEG-BASED EMOTION RECOGNITION

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arXiv

arXiv 2022年

作者： Wang, Zhe Wang, Yongxiong Hu, Chuanfei Yin, Zhong Song, Yu School of Optical-Electrical and Computer Engineering University of Shanghai for Science and Technology China Key Laboratory of Measurement and Control of CSE Ministry of Education Southeast University China Tianjin Key Laboratory for Control Theory and Applications in Complicated Systems Tianjin University of Technology China

Both the temporal dynamics and spatial correlations of Electroencephalogram (EEG), which contain discriminative emotion information, are essential for the emotion recognition. However, some redundant information within the EEG signals would degrade the performance. Specifically, the subjects reach prospective intense emotions for only a fraction of the stimulus duration. Besides, it is a challenge to extract discriminative features from the complex spatial correlations among a number of electrodes. To deal with the problems, we propose a transformer-based model to robustly capture temporal dynamics and spatial correlations of EEG. Especially, temporal feature extractors which share the weight among all the EEG channels are designed to adaptively extract dynamic context information from raw signals. Furthermore, multi-head self-attention mechanism within the transformers could adaptively localize the vital EEG fragments and emphasize the essential brain regions which contribute to the performance. To verify the effectiveness of the proposed method, we conduct the experiments on two public datasets, DEAP and MAHNOB-HCI. The results demonstrate that the proposed method achieves outstanding performance on arousal and valence classification. Copyright © 2022, The Authors. All rights reserved.

关键词： Emotion Recognition

A New Combined Heat Source Model of Hollow-Cathode Nanosecond Pulsed Electron Beam for Material Irradiation

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SSRN 2023年

作者： He, Weiguo Huo, Weijie Duan, Xinxin Zhu, Kangwu Wang, Feng School of Mechatronic Engineering and Automation Shanghai University Shanghai200444 China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou310024 China Key Laboratory of Gravitational Wave Precision Measurement of Zhejiang Province Taiji Laboratory for Gravitational Wave Universe Hangzhou310024 China Shanghai Aerospace Electronic Technology Institute Shanghai201109 China Shanghai Aerospace Control Technology Institute Shanghai201109 China

The hollow-cathode nanosecond pulsed electron beam changes the components and organization of the material surface through thermal coupling and prepares a modified layer on the surface of the base material with greatly optimized physicochemical and mechanical properties, which has a wide range of applications. In this study, in view of the insufficient research on the heat source model in the hollow-cathode nanosecond pulsed electron beam, a combined heat source model is proposed for the first time by abstracting the action of the hollow-cathode electron beam and the material as two sets of Gaussian heat sources with different parameters, and by equating the heat source of the action of the high-energy electron beam with the body heat source, and the action of the irradiation of the electron beam during the on-state phase with the surface heat source, respectively. Besides, the influence of heat source parameters on the temperature distribution is analyzed. The results show that for the nanosecond pulsed intense current electron beam-material interaction process, the use of a multi-parameter heat source model describes it more accurately compared to the average energy density values. At the same time, in order to further verify the accuracy of the model, a validation experiment was carried out using the titanium alloy Ti-6Al-4V material, and the experimental results show that the formation of irradiation morphology can be more accurately described using the combined heat source model with different storage energies, and the experimental results also show that uniform irradiation effect in a certain area can be realized by reasonably choosing the parameters of the energy storage capacitor. © 2023, The Authors. All rights reserved.

关键词： Electron beams

A Study of Discharge Cavity Optimization in Hollow-Cathode Electron Beam Source

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SSRN 2023年

作者： He, Weiguo Huo, Weijie Duan, Xinxin Gu, Jun Zhu, Kangwu School of Mechatronic Engineering and Automation Shanghai University Shanghai200444 China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou310024 China Key Laboratory of Gravitational Wave Precision Measurement of Zhejiang Province Taiji Laboratory for Gravitational Wave Universe Hangzhou310024 China Shanghai Aerospace Electronic Technology Institute Shanghai201109 China Shanghai SastSpace Technology Co. Ltd Shanghai201109 China Shanghai Aerospace Control Technology Institute Shanghai201109 China

Improving the high-voltage resistance of the discharge cavity is essential to enhancing the performance of the hollow-cathode electron source. In this work, a discharge cavity of the hollow-cathode electron beam source is designed and optimized by stacking and isolating the insulating sheets. The experimental results indicate that the optimized design not only improves the overall high-voltage resistance of the device but also improves the stability of the discharge. Meanwhile, it is found that when the amplitude of the discharge breakdown voltage is increased from 12 kV to 20 kV, the resistance of the discharge cavity varies within the range of 3.8–3.7 Ω, with a slight change in the amplitude, and the inductance decreases from 356 nH to 323.1 nH. The experimental study of the high-pressure gas discharge characteristics in the discharge cavity reveals that the change in gas pressure leads to a significant change in the discharge pattern, and compared with the glow discharge, the hollow-cathode discharge significantly improves the discharge current and shortens the breakdown time of the discharge. Under the same air pressure, the breakdown voltage of the discharge decreases and then increases with the increase in cathode cavity length. © 2023, The Authors. All rights reserved.

关键词： Glow discharges

Determination of hyperfine splittings and Landé gJfactors of 5s 2S1/2and 5p 2P1/2,3/2states of 111,113Cd+for a microwave frequency standard

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arXiv

arXiv 2022年

作者： Han, Jize Si, R. Qin, H.R. Xin, N.C. Chen, Y.T. Miao, S.N. Chen, C.Y. Zhang, J.W. Wang, L.J. State Key Laboratory Of Precision Measurement Technology And Instruments Key Laboratory Of Photon Measurement And Control Technology Of Ministry Of Education Department Of Precision Instrument Tsinghua University Beijing100084 China Shanghai EBIT Lab Key Laboratory Of Nuclear Physics And Ion-beam Application Institute Of Modern Physics Department Of Nuclear Science And Technology Fudan University Shanghai200433 China Department Of Physics Tsinghua University Beijing100084 China

Regarding trapped-ion microwave-frequency standards, we report on the determination of hyperfine splittings and Landé gJfactors of 111,113Cd+. The hyperfine splittings of the 5p 2P3/2state of 111,113Cd+ions were measured using laser-induced fluorescence spectroscopy. The Cd+ions were confined in a linear Paul trap and sympathetically cooled by Ca+ions. Furthermore, the hyperfine splittings and Landé gJfactors of the 5s 2S1/2and 5p 2P1/2,3/2levels of 111,113Cd+were calculated with greater accuracy using the multiconfiguration Dirac-Hartree-Fock scheme. The measured hyperfine splittings and the Dirac-Hartree-Fock calculation values were cross-checked, thereby further guaranteeing the reliability of our results. The results provided in this work can improve the signalto-noise ratio of the clock transition and the accuracy of the second-order Zeeman shift correction, and subsequently the stability and accuracy of the microwave frequency standard based on trapped Cd+ions. © 2022, CC BY.

关键词： Frequency standards

Study of Nanosecond Pulsed Hollow-Cathode Electron Beam Generation and Transportation Based on Pic-Mcc Simulation

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SSRN 2023年

作者： Huo, Weijie He, Weiguo Han, Luofeng Zhu, Kangwu Wang, Feng Shanghai Aerospace Electronic Technology Institute Shanghai201109 China School of Mechatronic Engineering and Automation Shanghai University Shanghai200444 China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou310024 China Key Laboratory of Gravitational Wave Precision Measurement of Zhejiang Province Taiji Laboratory for Gravitational Wave Universe Hangzhou310024 China Shanghai Aerospace Control Technology Institute Shanghai201109 China

This work employs the PIC-MCC method to study the nanosecond pulsed hollow-cathode discharge and electron beam generation process. The electron beam’s energy and current distribution characteristics at the anode exit are investigated, and the simulation’s grid and step sizes are set as 0.04 μm and 5*10-13 s, respectively. Experimental parameters are used in the simulation, and experimental results are also used to verify the simulation accuracy. The simulations investigate the transportation characteristics of the electron beam under different energies and currents and obtain the effects of voltage, current, and ion density on the distribution characteristics of the electron beam. The electron beam current generated by the hollow-cathode discharge is gradually transformed from a random distribution in the central region to a Gaussian distribution. Due to the ion channel caused by the action of runaway electron pre-ionization, the high-energy electron beam achieves focused transport over a certain distance, and the high-energy electron beam has a smaller Gaussian radius than the source input. Besides, the ion-focusing channel formed by the high-energy electron transportation process can realize the transportation of the high-current electron beam in the conduction stage. © 2023, The Authors. All rights reserved.

关键词： Electron beams

La-Doped Ceo2/Rgo Hybrid with High Oxygen Vacancy to Enhance Phosphorus Adsorption by Capacitive Deionization

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SSRN 2024年

作者： Qian, Hengfeng Zhang, Boshuang Song, Xiangju Jiang, Heqing Yang, Jianmao Liu, Jianyun College of Environmental Science and Engineering Textile Pollution Controlling Engineering Centre of Ministry of Ecology and Environment Donghua University Shanghai201620 China Qingdao Key Laboratory of Functional Membrane Material and Membrane Technology Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy ofSciences Qingdao266101 China ResearchCenterforAnalysis&Measurement DonghuaUniversity PRChina Shanghai201620 China Shanghai Institute of Pollution Control and Ecological Security PRChina Shanghai200092 China

Cerium oxide is one of the most attractive electrode materials in capacitive deionization (CDI) technology for selective phosphate adsorption due to the specific interaction. However, Ce3+/Ce4+ ratio and material conductivity of cerium oxide electrode determine the adsorption performance. Herein, a dual strategy was exploited with polyol-solvothermal reaction in the presence of graphite oxide and cerium salt followed by hydrothermal La-doping to obtain the three-dimensional (3D) assembly of La-doped CeO2 at the reduced graphene oxide (La-CeO2/rGO). The as-prepared La-CeO2/rGO hybrid exhibited interconnected structure with CeO2 uniformly distributed on the rGO support. La3+, by partially replacing Ce4+ in the lattice, was evenly fused into CeO2 nanosphere, enhancing the content of Ce3+ and oxygen vacancies and inhibiting lattice distortion. As a CDI anode, the La0.15-CeO2/rGO with optimal La doping achieved the maximum theoretical adsorption capacity of 118.7 mg P/g with high separation factor ( = 13.9), superior to the CeO2/rGO anode (67.8 mg P/g, = 10.1). In addition, the La-CeO2/rGO electrode is extremely robust, with excellent adsorption performance in wide pH range and good regeneration ability, compared to CeO2/rGO. This work proves that the synergy of trace La doping and 3D rGO support effectively improves the adsorption performance of La-CeO2/rGO electrodes and enhances the cycling stability of CDI devices. The corresponding adsorption mechanism was demonstrated. © 2024, The Authors. All rights reserved.

关键词： Oxygen vacancies