检索结果-内蒙古大学图书馆

SSRN 2023年

作者： Wang, Litian Chen, Jie Li, Dan Li, Cuiping Qian, Lirong Xiong, Yang Xie, Zhiyong Wang, Shuai Zhou, Tongyao Gai, Baojia Wang, Yinuo Tianjin Key Laboratory of Film Electronic and Communication Devices School of Integrated Circuit Science and Engineering Tianjin University of Technology Tianjin300384 China School of Integrated Circuit Science and Engineering Tianjin University of Technology Tianjin300384 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China Tianjin Bohua Yongli Chemical Industry CO. Ltd Tianjin30045 China

Protic ionic liquids (PILs) have emerged as promising solvents for CO2 capture, offering great potential for the development of efficient CO2 absorbents. Understanding the relationship between the PILs’ structures and CO2absorption mechanisms is instructive for advancing their applicability. Herein, an innovative strategy for CO2 capture using nonstoichiometric PILs was demonstrated for the first time. These nonstoichiometric PILs composed of imidazole (Im) as a Brønsted acid and 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) as a Brønsted base with various ratios. They exhibited both low viscosities and remarkable CO2 loading capacities, reaching up to 0.194 g CO2 /g IL and 1.42 mol CO2 /mol IL at 0.1 atm and 40 °C. The distribution of neutral and ionic species in these nonstoichiometric PILs was determined using density functional theory (DFT) calculations and nuclear magnetic (NMR) spectroscopy analysis. Correlations between the mole ratio of Brønsted acid and base and the viscosities, conductivities, and CO2 absorption properties were observed. The mechanism of CO2 absorption was proposed from the spectral results and DFT calculations. The superior CO2 loading ability of these PILs can be attributed to the formation of the zwitterionic carbamic complexes through interactions between CO2 and the N atom in DBU. Additionally, the presentence of Im significantly avoided the dramatic increase in the viscosity of the absorbents during CO2 absorption. It is believed that the new insights into the CO2 mechanism will facilitate the rational design of PILs for CO2 capture in the future. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

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CCUS—Opportunities and challenges to reducing carbon

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AIP Conference Proceedings 2024年第1期3203卷

作者： Yuqin Zeng Ye Sun National key laboratory of metallurgical intelligent manufacturing system automation research and design institute of metallurgical industry co.LTD Beijing China China iron & steel research institute group Beijing China

Fossil fuels, represented by coal, petroleum and natural gas have become key sources for productive activities since the Industrial Revolution. They have had a sustained adverse impact on the environment while improving industrial efficiency. In fact, CO2 play a major role in these effects. Therefore, the development of carbon reduction technologies has become the primary task to protect our environment. Carbon Capture, Utilization, and Storage (CCUS) technology is one of the important methods for achieving carbon peaking and carbon neutrality goals. CCUS technology has emerged as an urgent, necessary and strategic approach to reducing climate pollution caused by anthropogenic CO2 emissions, but it also entails numerous risks and social problems. Hence, this article provides an overview of current research on CCUS technology, summarizing the specific processes at each stage of CCUS technology, and analyzing the existing challenges of CCUS application in China’s.

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Investigation on Material Removal of the Sub-Aperture Tool Used for Polishing Riblet Surfaces

SSRN

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SSRN 2022年

作者： Wang, Guilian Lv, Bingrui Liu, Bin Fang, Fengzhou Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin 300384 China School of Mechanical and Materials Engineering University College Dublin Belfield D04 V1W8 Ireland Key Laboratory of Advanced Ceramics and Machining Technology Ministry of Education Tianjin University Tianjin300072 China Tianjin Laboratory of Control Theory and Applications in Complicated System School of Electrical and Electronic Engineering Tianjin University of Technology Tianjin 300384 China Tianjin University Tianjin 300072 China

Riblet surfaces find wide applications owing to their excellent performance such as drag reduction. In this study, sub-aperture tool is investigated to polish the riblet surfaces, two main different curvatures at any point of this kind of tool surface are proposed. A series of simulation studies are conducted to investigate the effect of key parameters on the material removal, such as tool radius, inclination angle, polishing pressure, and tool speed. The results show that a higher difference between the tool radius values in two directions increases the difference between the major and minor axes of the contact area. Based on experimental tests and simulation analysis, it is conluded that the profile and depth of material removal distribution both increase with an increase in polishing pressure, the material removal profile remains constant but the removal detpth increases with an increase in polishing speed, and the parameter K is a time-dependent. © 2022, The Authors. All rights reserved.

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Ultrafast demagnetization in ferromagnetic materials: origins and progress

arXiv

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arXiv 2024年

作者： Chen, Xiaowen Adam, Roman Bürgler, Daniel E. Wang, Fangzhou Lu, Zhenyan Pan, Lining Heidtfeld, Sarah Greb, Christian Liu, Meihong Liu, Qingfang Wang, Jianbo Schneider, Claus M. Cao, Derang College of Physics Qingdao University Qingdao266071 China National Demonstration Center for Experimental Applied Physics Education Qingdao University Qingdao266071 China Spin-X Institute South China University of Technology Guangzhou511442 China Peter Grünberg Institute Forschungszentrum Jülich Jülich52425 Germany Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials School of Physics and Electronics Hunan University of Science and Technology Xiangtan411201 China CAS Key Laboratory of Magnetic Materials and Devices Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo315201 China Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education Lanzhou University Lanzhou730000 China Key Laboratory of Special Functional Materials and Structural Design Ministry of Education Lanzhou University Lanzhou730000 China Faculty of Physics University of Duisburg-Essen Duisburg47057 Germany Department of Physics University of California Davis DavisCA95616-5270 United States

Since the discovery of ultrafast demagnetization in Ni thin films in 1996, laser-induced ultrafast spin dynamics have become a prominent research topic in the field of magnetism and spintronics. This development offers new possibilities for the advancement of spintronics and magnetic storage technology. The subject has drawn a substantial number of researchers, leading to a series of research endeavors. Various models have been proposed to elucidate the physical processes underlying laser-induced ultrafast spin dynamics in ferromagnetic materials. However, the potential origins of these processes across different material systems and the true contributions of these different origins remain challenging in the realm of ultrafast spin dynamics. This predicament also hinders the development of spintronic terahertz emitters. In this review, we initially introduce the different experimental methods used in laser-induced ultrafast spin dynamics. We then systematically explore the magnetization precession process and present seven models of ultrafast demagnetization in ferromagnetic materials. Subsequently, we discuss the physical processes and research status of four ultrafast demagnetization origins (including spin-flipping, spin transport, non-thermal electronic distribution, and laser-induced lattice strain). Since attosecond laser technique and antiferromagnetic materials exhibit promising applications in ultrahigh-frequency spintronics, we acknowledge the emerging studies used by attosecond pules and studies on ultrafast spin dynamics in antiferromagnets, noting the significant challenges that need to be addressed in these burgeoning field. © 2024, CC BY.

关键词： Spin dynamics

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Anomalous Polarization-Switching Phenomena and Noteworthy Pyroelectricity in Ferroelectric Hf0.5zr0.5o2 Polycrystalline Films

SSRN

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SSRN 2023年

作者： Wang, Xudong Zhou, Yong Xiong, Ke Wu, Shuyu Tu, Luqi Chen, Yan Wu, Shuaiqin Zeng, Jinhua Zheng, Yuqing Gu, Shiqun Luo, Man Lin, Tie Shen, Hong Meng, Xiangjian Liu, Qi Chu, Junhao Wang, Jianlu State Key Laboratory of Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai200083 China Key Laboratory of Microelectronics Device and Integrated Technology Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China Frontier Institute of Chip and System Fudan University Shanghai200433 China Shanghai Frontier Base of Intelligent Optoelectronics and Perception Institute of Optoelectronics Fudan University Shanghai200433 China Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Chinese Academy of Sciences Hangzhou330106 China BirenTech Shanghai201114 China Jiangsu Key Laboratory of ASIC Design School of Information Science and Technology Nantong University Jiangsu Nantong226019 China

Hafnia-based oxide thin films exhibit unconventional robust ferroelectricity at the nanoscale, paving the way for advancements in next-generation nanoelectronics. However, the stability and dynamics of ferroelectric polarization in hafnia-based oxides films, particularly at the nanoscale, warrant further exploration. In this study, we delve into the factors influencing the formation of the ferroelectric phase. Our findings illuminate that the confinement effect of the capped layer enhances the stabilization of the metastable orthorhombic phase, thereby bolstering its ferroelectricity and endurance. Furthermore, we identify an unprecedented polarization-switching behavior in HfO2-based ferroelectric films, characterized by a decrease in the remanent polarization and an increase in the coercive field as the temperature drops. This peculiar phenomenon can be ascribed to the reduction in the long-range interaction of polarization dipoles upon cooling, as evidenced by the dielectric spectrum. The diminished long-range interaction results in the emergence of nanodomains and a re-entrant relaxer behavior, offering novel insights into the origin of ferroelectricity and the stability of ferroelectric polarization in hafnia-based thin films. Given the commendable compatibility of Hf0.5Zr0.5O2 films with Si substrates and a pyroelectric coefficient of -62.1 μC/m2·K, they emerge as a prime candidate for sensor device applications. © 2023, The Authors. All rights reserved.

关键词： Thin films

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design of an Active Battery Equalization Circuit with DC-DC Converter

Design of an Active Battery Equalization Circuit with DC-DC ...

引用

IEEE Asia Power and Energy Engineering Conference (APEEC)

作者： Kun Li Xiao Zong Qing Liu Yanfang Sun Fengjun Xue Tianjin Key Laboratory of Film Electronic and Communication Device Tianjin University of Technology Tianjin PR China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin PR China Wuhan Running Education Research Institute Wuhan PR China

ISBN: (纸本)9781665425513;9781665430791

An active balanced topology circuit based on DC-DC converter is proposed in this paper. It uses the energy of the whole battery pack to charge the lowest voltage cell. In the control strategy, starting and stopping the equalization is well controlled by setting the appropriate thresholds of voltage difference between each cell. Experiment board which can sample and equalize 16 batteries is manufactured, and the experimental results verify the effectiveness of the proposed equalization system.

关键词： Electrical engineering Energy exchange Asia DC-DC power converters Threshold voltage Batteries Topology

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Significant Wave Height Prediction Based on VMD-SA-MLP-BP

Significant Wave Height Prediction Based on VMD-SA-MLP-BP

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Chinese Automation Congress (CAC)

作者： Yining Wu Runfeng Zhang Fang Liu Zhenzhong Liu Jianguo Wu Haonan Dong Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Yichang Research Institute of Testing Technology Yichang China Tianjin Hanhailanfan Marine Technology Co. Ltd. Tianjin China School of Computer Science and Engineering Tianjin University of Technology Tianjin China

Waves seriously impact port construction, worldwide route planning, military activities, and wave power generation. To improve the accuracy of significant wave height prediction, we proposed a novel prediction method, a multi-layer perceptron combined with a backpropagation adjustment (MLP-BP) prediction model that combines mutation mode decomposition (VMD) and a simulated annealing optimization algorithm (SA). Firstly, we use the variable modulus method to decompose the significant wave height sequence data and transform the wave height sequence into multiple different sub-modes (IMF) to reduce the complexity and non-stationarity of the data. Secondly, the simulated annealing algorithm (SA) is used to optimize the weight and bias of the MLP-BP neural network to find the optimal parameter configuration and improve the performance and generalization ability of the prediction model. Finally, the decomposed sub-modal components of each significant wave height sequence are inserted into the MLP-BP neural network and the predicted values of each element are summed to obtain the final significant wave height prediction. The prediction results of the SSA-MLP-BP, PSO-MLP-BP, SA-MLP-BP, and VMD-SA-MLP-BP were compared and demonstrated that the VMD-SA-MLP-BP model performed best. The MAE, MAPE, MSE, RMSE, and R2 of the prediction evaluation indexes were 0.036 m, 11.7%, 0.004 m 2 , 0.067 m, and 0.983, respectively, which performed well in predicting significant wave height.

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Optimization of Experiment Teaching in the Course of Mechanical Principle 2020

Optimization of Experiment Teaching in the Course of Mechani...

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2020 3rd International Conference on Education Technology Management

作者： Pujun Hao Jingna Liu Wenpeng Ma Ruiqin Wu Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin and National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) China

ISBN: (纸本)9781450388757

Based on experience of former teaching reformation and philosophy of "Emerging Engineering Education", an experimental teaching reformation program that includes restructured knowledge system, modularization of experimental teaching process and diversified evaluation system is proposed. It is found that students have deeper and comprehensive understanding on knowledge and more enthusiasm in experimental process. Finally students have definite self-cognition about their division of labor in teamwork. Through gathering statistics, the effectiveness of reformation program is verified and this program can enrich practical experience of experimental teaching reformation.

关键词： experiment teaching diversified evaluation modular teaching process Mechanical principle

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Curriculum Reform of "Fundamentals of Mechanical design" for Non-Mechanical Majors Based on OBE Engineering Education Concept 2020

Curriculum Reform of "Fundamentals of Mechanical Design" for...

引用

2020 3rd International Conference on Education Technology Management

作者： Jingna Liu Pujun Hao Linwei Lyu Wenpeng Ma Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin and National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) China

ISBN: (纸本)9781450388757

Focusing on the non-mechanical students' weak mechanical knowledge, a new cultivation mode founded on the outcome-oriented education (OBE) is suggested to improve the teaching effect for "Fundamentals of mechanical design". The teaching course contents are optimized to make students' learning process proceed simultaneously with project case study. The teaching methods of innovative project driven and problem-oriented are adopted. Students can be guide to change the passive learning mode by autonomous learning mode with the online learning resources. The innovative methods can be recommended to the process of curriculum design to reform the content. The course experiment has been changed into online and offline mixed teaching, so as to improve students' experimental practice time and cultivate their ability of integrating theory with practice, analyzing problems and solving problems. Finally, the formative evaluation mode with the learning results as the assessment index is adopted to improve the students' comprehensive ability. Compared with the control class, the experimental class has greatly improved the excellent rate and pass rate. In the questionnaire survey, the experimental class students have a higher recognition for the curriculum reform.

关键词： curriculum reform learning outcomes oriented Engineering education concept fundamentals of mechanical design

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Inverse design of composite pipe fittings using deep learning for lightweight structural optimization

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Composites Communications 2025年

作者： Qichao Gui Anchalee Duongthipthewa Limin Zhou School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen 518055 PR China Guangdong Provisional Key Laboratory of Functional Oxide Materials and Devices Southern University of Science and Technology Shenzhen 518055 PR China Shenzhen Key Laboratory of Intelligent Manufacturing for Continuous Carbon Fiber Reinforced Composites Southern University of Science and Technology Shenzhen 518055 PR China

The conventional design of composite pipe fittings is highly dependent on experimental testing and finite element simulations, which are both costly and time-intensive. To address these challenges, this study introduces a deep learning-based inverse design approach to optimize the stiffness characteristics of carbon fiber reinforced polymer (CFRP) composite pipe fittings. Two predictive models were developed: a Long-Short-Term Memory-Based (LSTMB) Model and a Multi-Head Attention-Based (MHAB) *** evaluations revealed that the MHAB model outperformed the LSTMB model in terms of predictive accuracy and generalization capability. Based on this, a population-based optimization algorithm was integrated to achieve the inverse design of the composite pipe fittings, ensuring efficient structural optimization while satisfying design constraints. The proposed method was validated through two optimization case studies, demonstrating its effectiveness in improving the efficiency and precision of composite pipe fitting design. This study highlights the potential of deep learning, particularly the Transformer framework, to accelerate the design and optimization of composite materials.

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