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Fine Doppler shift acquisition algorithm for BeiDou software receiver by a look-up table

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Journal of Systems engineering and Electronics 2020年第3期31卷 612-625页

作者： QIU Wenqi ZENG Qingxi GAO Chang LYU Chade State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130012China Non-destructive Detection and Monitoring Technology for High-speed Transportation Facilities Key Laboratory of Ministry of Industry and Information Technology Nanjing 211106China College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

The BeiDou software receiver uses the fast Fourier transform(FFT)to perform the *** Doppler shift estimation accuracy should be less than 500 Hz to ensure satellite signals to enter a locked state in the tracking *** the frequency step is usually 500 Hz or larger,the Doppler shift estimation accuracy cannot guarantee that satellite signals are brought into a stable tracking *** straightforward solutions consist in increasing the sampling time and using zero-padding to improve the frequency resolution of the ***,these solutions intensify the complexity and amount of *** contradiction between the acquisition accuracy and the computational load leads us to research for a more simple and effective algorithm,which achieves fine acquisition by a look-up *** coarse acquisition using the parallel frequency acquisition(PFA)algorithm,the proposed algorithm optimizes the Doppler shift estimation through the look-up table method based on the FFT results to improve the acquisition accuracy of the Doppler shift with a minimal additional computing *** the Doppler shift is within the queryable range of the table,the proposed algorithm can improve the Doppler shift estimation accuracy to 50 Hz for the BeiDou B1I signal.

关键词： fine acquisition fast Fourier transform(FFT) table look-up parallel frequency acquisition(PFA) BeiDou

Overlooked Oxidative Role of Ni(Iii) in the Enhanced Mineralization of Ni(Ii)–Edta Complex by Ozonation

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SSRN 2022年

作者： Zong, Yang Ji, Wenjie Xie, Yu Wu, Deli State Key Laboratory of Pollution Control and Resources Reuse College of Environmental Science & Engineering Tongji University Shanghai200092 China Shanghai Institute of Pollution Control and Ecological Security Shanghai200092 China

The mineralization of organic pollutant by O3 is prone to be restricted by the accumulative production of hydroxyl radical (•OH)-recalcitrant oxalate (OA). Herein, it was interestingly found that the presence of 0.5 mM Ni(II) enhanced the mineralization efficiency of EDTA by O3 under alkaline conditions by 22.8%, and the promoting effect of Ni(II) augmented with the increased loading of Ni(II). Based on the results from scavenging experiment, chemical probe detection and XPS characterization, it was verified that except for the commonly recognized reactive oxidants (i.e., •OH and O3) in EDTA mineralization, the overlooked Ni(III) species (i.e., NiOOH) also played an indispensable role in the enhanced mineralization of EDTA. The Ni(III) species was formed via the oxidation of decomplexed Ni(II) by •OH and in turn collaborated with •OH to decompose EDTA. More importantly, the generated Ni(III) species exerted higher affinity towards •OH and O3-resistent oxalate, hence elevating EDTA mineralization. This study elucidated the significant role of Ni(III) species in enhancing the mineralization efficiency of EDTA, and also proposed a new insight into promoting the treatment performance of ozonation via the collaborative oxidation mechanism-co-mediated by •OH and Ni(III) species. © 2022, The Authors. All rights reserved.

关键词： Ozonization

Intelligent Vehicle Path Planning Considering Side Slip of Surrounding Vehicles in Icy and Snowy Environment

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Intelligent Vehicle Path Planning Considering Side Slip of S...

Conference on Vehicle control and Intelligence (CVCI)

作者： Hongyan Guo Wei Zhao Jun Liu Xiaoming Zhao The State Key Laboratory of Automotive Simulation and Control The College of Communication Engineering Jilin University Changchun China The State Key Laboratory of Automotive Simulation and Control Jilin University Changchun China

ISBN: (纸本)9781665408486

Under the icy and snowy environment, the road conditions are complex and changeable, especially the reduction of road adhesion coefficient, which brings great challenges to the driving safety of intelligent vehicles. Aiming at the problem that the peripheral vehicle may be unstable at any time in the ice and snow environment, a path planning method considering the side slip of the peripheral vehicle in the icy and snowy environment is proposed in this paper. Firstly, reinforcement learning and artificial potential field are combined to transform the force received by the vehicle in the artificial potential field into the objective function in reinforcement learning for reinforcement learning training. Then, because this paper studies the path planning in the icy and snowy environment, considering that the sideslip of the obstacle vehicle will bring a safety threat to the vehicle, the dynamic rectangular virtual repulsion field of the obstacle vehicle is adjusted accordingly during the sideslip. So that the vehicle will be more repulsed by the obstacle vehicle at this time, and guide the vehicle to avoid the dangerous vehicle in time. Finally, the path planning results are simulated and verified in Matlab / CarSim software. The simulation results show that the path planning method in this paper can effectively make the vehicle avoid obstacles safely and stably, and the planned path meets the dynamic requirements of the vehicle and driving stability.

关键词： Q-learning Intelligent vehicles Adhesives Roads Simulation Wheels Path planning

Re-defining the performance of just-in-time learning based soft sensor for high dimensional process data

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Re-defining the performance of just-in-time learning based s...

第32届中国过程控制会议(CPCC2021)

作者： Xiaoyu Jiang Zhiqiang Ge State Key Laboratory of Industrial Control Technology Institute of Industrial Process ControlCollege of Control Science and EngineeringZhejiang University

Just-in-time learning(JITL) is a widely used online soft sensing method for time-varying *** the increase of dimensionality of industrial dataset,both reliability and usability of JITL would be seriously damaged due to the sparseness caused in the high-dimensional data *** this paper,variational autoencoder is introduced as a generative model to provide virtual samples for augmenting high-dimensional sparse *** on this,a data augmentation just-in-time learning framework is formulated and implemented with two different ***,we carefully discuss the effect of virtual data on just-in-time learning,as well as the influence of virtual data volume,virtual data ratio and other factors on the proposed ***,a real industrial example is applied to verify the effectiveness of the proposed method,in which two indicators(RMSE and R2) have been improved by an average of 22%,15%,respectively,compared to the traditional JITL approach.

关键词： Data augmentation just-in-time learning variational autoencoder soft sensor

Uptake of polycyclic aromatic hydrocarbons (PAHs) from PAH–contaminated soils to carrots and Chinese cabbages under the greenhouse and field conditions

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Chemosphere 2024年 360卷 142405页

作者： Cao, Chun Wu, Yu-Yao Lv, Zhen-Ying Wang, Ji-Wei Wang, Chen-Wen Zhang, Hui Wang, Jun-Jian Chen, Huan College of Geography and Environmental Science Northwest Normal University Gansu Lanzhou730070 China Key Laboratory of Resource Environment and Sustainable Development of Oasis Gansu Lanzhou730070 China Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Lanzhou730000 China University of Chinese Academy of Sciences Beijing100049 China College of Resources and Environment Chengdu University of Information Technology Chengdu610225 China Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control School of Environmental Science and Engineering Southern University of Science and Technology Shenzhen518055 China State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control School of Environmental Science and Engineering Southern University of Science and Technology Shenzhen518055 China Department of Environmental Engineering and Earth Science Clemson University SC29634 United States

Polycyclic aromatic hydrocarbons (PAHs) with the properties of structural stability, semi–volatility, and hydrophobicity are toxic and persistent in environments;thus, their transport and fate in agroecosystems is essential for reducing PAH accumulation in the edible parts of crops. Here, we cultivated cabbages (Brassica pekinensis L.) and carrots (Daucus carota L.) in PAH–contaminated soils under the greenhouse and field conditions. After harvesting, we observed a 9.5–46% reduction in soil ∑PAH concentrations. There were 37% of bioconcentration factors (BCFbs) > 1 and 93% of translocation factors (TFab) > 1, while low–molecular–weight (LMW) PAHs had higher BCFbs than high–molecular–weight (HMW) PAHs. The PAH concentrations showed significant and positive correlations among soils, the belowground parts, and the aboveground parts. The toxicity equivalent concentration (TEQBaP) followed the order of cabbage (greenhouse) > cabbage (field) > carrot (greenhouse) > carrot (field), suggesting potentially higher health risks in cabbage relative to carrot and vegetables under the greenhouse relative to field condition. Our study suggested growing carrots under field conditions as a management strategy for reducing the risks of vegetables grown in PAH–contaminated soils. © 2024 Elsevier Ltd

关键词： Health risks

Efficient Decomposition of Pfos by Hydrated Electrons: Performance, Mechanism and Carbon Emission Reduction

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SSRN 2022年

作者： Chu, Liquan Zhang, Chaojie Chen, Pei Zhou, Qi Zhou, Xuefei Zhang, Yalie State Key Laboratory of Pollution Control and Resources Reuse College of Environmental Science and Engineering Tongji University Shanghai200092 China Shanghai Institute of Pollution Control and Ecological Security Shanghai200092 China

Perfluorooctane sulfonate (PFOS) is a typical perfluorinated compound, and the presence of sulfonic groups makes it more difficult to decompose. In this study, ultraviolet photolysis of iodide (UV/KI) was conducted to generate hydrated electrons for PFOS decomposition, the key factors affecting the decomposition efficiency were investigated and the possible decomposition pathways were speculated. The results implied that the UV/KI system can effectively promote the decomposition and defluorination of PFOS. When the PFOS and KI concentrations were 0.03 mmol L-1 and 0.3 mmol L-1, the decomposition and defluorination efficiency of PFOS at pH 10 reached 99.5% and 94.8% after 12 hours of reaction, respectively. With the increase of KI concentration from 0.1 to 0.5 mmol L-1, the decomposition and defluorination efficiency of PFOS increased, but a further increase of KI will lead to a decrease in the performance. Weak and strong alkaline conditions were more favorable for PFOS decomposition than acid conditions. Compared with UV/Sulfite system, this system can be conducted under a lower concentration of hydrated electron source chemicals and a wider range of pH. Kinetic analysis implied that PFOS decomposition followed the pseudo-first-order model with a reaction rate constant of 1.004 h-1, which was higher than most PFOS decomposition processes. Intermediates analysis and mass balance indicated there were three decomposition pathways of PFOS: desulfonation, H/F exchange and C-C bond dissociation. The main products were harmless fluorine ions, formic acid and acetic acid, which suggested that the UV/KI system for PFOS decomposition is a relatively mild and green process. © 2022, The Authors. All rights reserved.

关键词： Rate constants

Circulating Current Injection Method for the Modular Multilevel Converter 1

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Circulating Current Injection Method for the Modular Multile...

1st IEEE International Power Electronics and Application Symposium, PEAS 2021

作者： Jia, Guanlong Li, Mingshuo Su, Xiaotong Tang, Song Liu, Xiaoming Jiang, Wentao HeBei University of Technology State Key Lab of Reliability And Intelligence of Electrical Equipment Tianjin China Zhe Jiang University College of Eletrical Engineering Hangzhou China Tiangong University Tianjin Key Laboratory of Intelligent Control of Electrical Equipment Tianjin China

ISBN: (纸本)9781665413596

The circulating current of modular multilevel converter (MMC) is an inherent phenomenon. The existing circulating current analysis methods have mainly considered the power losses and the submodule (SM) capacitor voltage. Under low-frequency operation, MMC SM has a larger capacitor voltage ripple, and this paper proposes a novel circulating current injection method to reduce the SM capacitor voltage ripple. The method is based on injecting a circulating current, which is easily derived by the instantaneous information of MMC, within the phase to attenuate the lower frequency arm powers. And, it omits using an extensive lookup table and injecting a common-mode voltage, thus simplifies the control and avoids causing over-modulation. In addition, a mathematical analysis model is built and it reveals the impact on the SM capacitor voltage ripple. The effectiveness of the introduced circulating current injection method is demonstrated by the experimental results. © 2021 IEEE.

关键词： Table lookup

New Sight into the Enhanced Ozonation of Malodorous Compounds by Cu(Ii): Inhibiting the Formation of Free Radicals to Promote Ozone Utilization

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SSRN 2022年

作者： Lin, Xiaoqing Ma, Canming Wu, Deli State Key Laboratory of Pollution Control and Resources Reuse College of Environmental Science & Engineering Tongji University Shanghai200092 China Shanghai Institute of Pollution Control and Ecological Security Shanghai200092 China

Metal-enhanced ozonation can greatly improve the decay of organic matter;however, whether this method benefits the decay of malodorous compounds or not and the possible mechanism are not well understood. In this study, nine typical malodorous compounds were selected to reveal that Cu(II)-enhanced ozonation can greatly promote the decay of fatty amines because of the direct ozone oxidation, which was enhanced to promote ozone utilization. Moreover, trace Cu(II) can amplify the observed rate constants of dimethylamine and trimethylamine for 48.9% and 155.7%, respectively and Cu(II) dosage was the determining factor using response surface methodology to investigate the interactions between initial pH, Cu(II) dosage and ozone dosage. These results demonstrated that the formation of •OH and O2•– was inhibited rather than promoted, which was quite different from some previously reported Cu(II)-enhanced ozonation counterparts. Moreover, the enhanced effect of trace Cu(II) was exhibited in both single and complex malodorous compounds. The conversion pathway of nitrogen and sulfur elements was clarified, with the targeted mineralization of nitrogen of nitrogen-containing malodorous compounds into NO3-N and the odor characteristics of sulfur-containing malodorous compounds disappeared. These findings provided new insight for utilizing metal ions to enhance the direct ozone oxidation capacity of malodorous compounds. © 2022, The Authors. All rights reserved.

关键词： Ozone

A Highly Efficient Method for Analysis Cefadroxil Antibiotic Hydrolysis Based on Electrochemical Fingerprints

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SSRN 2022年

作者： Zhu, Xiaoyu Zhang, Huirong Zhai, Yongxin Wang, Ying State Key Laboratory of Pollution Control and Resources Reuse College of Environmental Science and Engineering Tongji University Shanghai 200092 China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092 China

Understanding antibiotic hydrolysis rates are important for predicting their environmental persistence as biologically active contaminants. In this study, hydrolysis rates and Arrhenius constants were determined as a function of pH and temperature for cefadroxil antibiotics by the electrochemical method. Hydrolysis rate and half-life were studied as a function of temperature (5, 25, and 45°C), and pH (1, 3, 5, 7, 9, and 11). The antibiotics were hydrolyzed under ambient conditions (pH 7 and 25 °C);half-live was 11 d by electrochemical method. Base-catalyzed hydrolysis rates were significantly greater than acid-catalyzed and neutral pH hydrolysis rates. Hydrolysis rates increased 2.6- to 3.3-fold for a 10 °C increase in temperature. Meanwhile, the hydrolysis product was also determined by the electrochemical approach and the potential degradation pathway was proposed based on mass spectrometry results. The results of this research demonstrate that degradation of β-lactam antibiotics will likely occur over several weeks in most surface waters and over several days in more alkaline systems. Our research shows a new method that under typical environmental conditions (pH and temperature) β -lactam antibiotics are hydrolytically stable with a long half-life;they thus contribute to the ongoing assessment of their environmental fate. © 2022, The Authors. All rights reserved.

关键词： Antibiotics