检索结果-南通市图书馆

Control Strategies for Digital Twin Systems

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 170-180页

作者： Guo-Ping liu IEEE the Center for Control Science and Technology Southern University of Science and TechnologyShenzhen 518055China

With the continuous breakthrough in information technology and its integration into practical applications, industrial digital twins are expected to accelerate their development in the near future. This paper studies various control strategies for digital twin systems from the viewpoint of practical *** make full use of advantages of digital twins for control systems, an architecture of digital twin control systems, adaptive model tracking scheme, performance prediction scheme, performance retention scheme, and fault tolerant control scheme are proposed. Those schemes are detailed to deal with different issues on model tracking, performance prediction, performance retention, and fault tolerant control of digital twin systems. Also, the stability of digital twin control systems is analysed. The proposed schemes for digital twin control systems are illustrated by examples.

关键词： Digital twin control systems fault tolerant control model tracking performance prediction performance retention

Relation Between the Eventual Continuity and the E-property for Markov-Feller Semigroups

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2024年第1期40卷 1-16页

作者： Yong liu Zi-yu liu LMAM School of Mathematical SciencePeking UniversityBeijing100871China

We investigate some relations between two kinds of semigroup regularities, namely the e-property and the eventual continuity, both of which contribute to the ergodicity for Markov processes on Polish *** precisely, we prove that for Markov-Feller semigroup in discrete time and stochastically continuous MarkovFeller semigroup in continuous time, if there exists an ergodic measure whose support has a nonempty interior,then the e-property is satisfied on the interior of the support. In particular, it implies that, restricted on the support of each ergodic measure, the e-property and the eventual continuity are equivalent for the discrete-time and the stochastically continuous continuous-time Markov-Feller semigroups.

关键词： Markov-Feller semigroup ergodicity e-property eventual continuity

Research on Anthropomorphic Obstacle Avoidance Trajectory Planning for Adaptive Driving Scenarios Based on Inverse Reinforcement Learning Theory

在线全文

学校读者我要写书评

暂无评论

Engineering 2024年第2期33卷 133-145页

作者： Jian Wu Yang Yan Yulong liu Yahui liu School of Mechanical and Automotive Engineering Liaocheng UniversityLiaocheng 252000China 2 School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China

The forward design of trajectory planning strategies requires preset trajectory optimization functions,resulting in poor adaptability of the strategy and an inability to accurately generate obstacle avoidance trajectories that conform to real driver behavior *** addition,owing to the strong time-varying dynamic characteristics of obstacle avoidance scenarios,it is necessary to design numerous trajectory optimization functions and adjust the corresponding ***,an anthropomorphic obstacle-avoidance trajectory planning strategy for adaptive driving scenarios is ***,numerous expert-demonstrated trajectories are extracted from the HighD natural driving ***,a trajectory expectation feature-matching algorithm is proposed that uses maximum entropy inverse reinforcement learning theory to learn the extracted expert-demonstrated trajectories and achieve automatic acquisition of the optimization function of the expert-demonstrated ***,a mapping model is constructed by combining the key driving scenario information that affects vehicle obstacle avoidance with the weight of the optimization function,and an anthropomorphic obstacle avoidance trajectory planning strategy for adaptive driving scenarios is ***,the proposed strategy is verified based on real driving *** results show that the strategy can adjust the weight distribution of the trajectory optimization function in real time according to the“emergency degree”of obstacle avoidance and the state of the ***,this strategy can generate anthropomorphic trajectories that are similar to expert-demonstrated trajectories,effectively improving the adaptability and acceptability of trajectories in driving scenarios.

关键词： Obstacle avoidance trajectory planning Inverse reinforcement theory Anthropomorphic Adaptive driving scenarios

Graph Signal Reconstruction from Low-Resolution Multi-Bit Observations

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第1期33卷 153-160页

作者： Zhaoting liu Chen YU Yafeng WANG Shuchen liu School of Communication Engineering Hangzhou Dianzi University

Low hardware cost and power consumption in information transmission, processing and storage is an urgent demand for many big data problems, in which the high-dimensional data often be modelled as graph *** paper considers the problem of recovering a smooth graph signal by using its low-resolution multi-bit quantized observations. The underlying problem is formulated as a regularized maximum-likelihood optimization and is solved via an expectation maximization scheme. With this scheme, the multi-bit graph signal recovery(MB-GSR) is efficiently implemented by using the quantized observations collected from random subsets of graph nodes. The simulation results show that increasing the sampling resolution to 2 or 3 bits per sample leads to a considerable performance improvement, while the energy consumption and implementation costs remain much lower compared to the implementation of high resolution sampling.

关键词： Quantization (signal) Costs Power demand Simulation Energy resolution Signal sampling Signal reconstruction

Synthesis of core-shell nanostructured SiO_(2)/TiO_(2)photocatalysts via atomic layer deposition in a fluidized bed with central tube

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第8期91卷 19-28页

作者： Wei liu Daoyin liu Zuyang Zhang Zhenkun Sun Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy&EnvironmentSoutheast UniversityNanjing 210096China

Fluidized bed atomic layer deposition is an efficient technique for particle coating with precise control over the film thickness and uniformity at the *** this study,a fluidized bed with a central tube is designed,where the central tube has two roles:improve fluidization and deliver precursors *** synthesis of core-shell structured SiO_(2)/TiO_(2)nanoparticle catalysts for photodegradation of tetracycline hydrochloride(TC)is carried out using TiCl_(4)and H_(2)O as precursors at 180℃under atmospheric *** the combination of vibration and central tube,the segregation of agglomerate size along the bed height is weakened,and the prepared SiO_(2)/TiO_(2)nanoparticles show excellent photocatalytic degradation performance:the degradation efficiency on TC is 96%under 300 W xenon lamp irradiation for 60 *** mechanism of enhanced photocatalytic activity is due to the Ti-O-Si bonds generated at the interface,which increase the ability to absorb sunlight and accelerate the separation of holes and electrons.

关键词： SiO_(2)/TiO_(2)nanoparticles Fluidization Atomic layer deposition Photocatalysts Photocatalytic mechanism

Optimized the vanadium electrolyte with sulfate-phosphoric mixed acids to enhance the stable operation at high-temperature

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2024年第2期18卷 13-26页

作者： Ling Ge Tao liu Yimin Zhang Hong liu School of Resource and Environmental Engineering Wuhan University of Science and TechnologyWuhan 430081China State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control Wuhan University of Science and TechnologyWuhan 430081China Hubei Collaborative Innovation Center for High Efficient Utilization of Vanadium Resources Wuhan University of Science and TechnologyWuhan 430081China Hubei Provincial Engineering Technology Research Center of High Efficient Cleaning Utilization for Shale Vanadium Resource Wuhan University of Science and TechnologyWuhan 430081China School of Resource and Environmental Engineering Wuhan University of TechnologyWuhan 430070China

Herein, the influence of the concentration design and comprehensive performance of the sulfate-phosphoric mixed acid system electrolyte is investigated to realize an electrolyte that maintains high energy density and stable operation at high temperatures. Static stability tests have shown that VOPO4 precipitation occurs only with vanadium(V) electrolyte. The concentration of vanadium ion of 2.0–2.2 mol·L^(–1), phosphoric acid of 0.10–0.15 mol·L^(–1), and sulfuric acid of 2.5–3.0 mol·L^(–1) are suitable for a vanadium redox flow battery in the temperature range from –20 to 50 ℃. The equations for predicting the viscosity and conductivity of electrolytes are obtained by the response surface method. The optimized electrolyte overcomes precipitation generation. It has 2.8 times higher energy density than the non-phosphate electrolyte, and a coulomb efficiency of 94.0% at 50 ℃. The sulfate-phosphoric mixed acid system electrolyte promotes the electrode reaction process, increases the current density, and reduces the resistance. This work systematically optimizes the concentrations of composition of positive and negative vanadium electrolytes with mixed sulfate-phosphoric acid. It provides a basis for the different valence states and comprehensive properties of sulfate-phosphoric mixed acid system vanadium electrolytes under extreme environments, guiding engineering applications.

关键词： all vanadium redox flow battery mixed-acid vanadium electrolyte concentration optimization response surface methodology high-temperature stability

Performance analysis and multi-objective optimization based on a modified irreversible Stirling cycle

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第6期67卷 1668-1684页

作者： XU Lei YU MinJie liu ZhiChun liu Wei School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan430074China

The efficiency of the actual Stirling engine is much lower than the ideal Carnot cycle *** obtain more precise efficiency for Stirling engines,this paper proposes a modified Stirling cycle with a more accurate heat transfer process in Stirling engines based on a thermodynamic function called available *** finite-time thermodynamic method is used to analyze the model performance under constant heat source temperature,finite temperature difference heat transfer,and incomplete regenerative processes.A new polytropic process is introduced to model the heat transfer between the working fluid and external heat sources in which only heat above ambient temperature is converted into technical *** regenerator is divided into numerous smaller heat reservoirs with individual temperature to analyze the incomplete regenerative *** expressions of the output power and thermal efficiency are obtained based on the modified irreversible Stirling cycle,and the effects of irreversible losses are analyzed to evaluate the performance of the proposed *** indicate that the efficiency of the modified cycle is much lower than that of the ideal Stirling cycle with an isothermal *** the increase of the average heat transfer temperature difference,there exists an optimum value for the power of the irreversible *** optimum power of the model was obtained for varying thermodynamic parameters by optimizing the average heat transfer temperature difference between the hot and cold *** optimize the irreversible model,the multi-objective optimization analysis is carried out based on NSGA-Ⅱ,which results in an optimized output power of 40.87 kW and an optimized thermal efficiency of 44%.

关键词： stirling cycle regenerative processes isopotential processes multi-objective optimization finite time thermodynamics

Lanthanide-based microlasers:Synthesis,structures,and biomedical applications

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第1期17卷 97-111页

作者： Qian Zhang Yawei liu Kai liu Hongjie Zhang Engineering Research Center of Advanced Rare Earth Materials(Ministry of Education) Department of ChemistryTsinghua UniversityBeijing 100084China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Xiangfu Laboratory Jiaxing 314102China

The large size of lasers limits their applications in confined spaces,such as in biosensing and in vivo brain tissue *** this regard,micron-sized lasers have been *** exhibit great potential for biological detecting,remote sensing,and depth tracking due to their small sizes,sensitive properties of their spectral fingerprints,and flexible positional modulation in the ***-based luminescent materials that possess long excited-state lifetime,narrow emission bandwidth,and upconversion behaviors are promising as gain mediums for novel *** addition,lanthanide-based microlasers could be generated under natural ambient conditions with pumped or continuous light sources,which significantly promotes the practical applications of *** progress in the design,synthesis,and biomedical applications of lanthanide-based microlasers has been outlined in this *** ions doped and upconverted lanthanide-based microlasers are highlighted,which exhibit advantageous structures,miniaturized dimensions,and high lasing *** applications of lanthanide-based microlasers are further discussed,the upconverted microlasers show great advantages for biological applications owing to their tunable excitation and emission characteristics and excellent environmental ***,perspectives and challenges in the field of lanthanide-based microlasers are presented.

关键词： microlasers lanthanide-based luminescent materials upconversion nanoparticles biological applications

Design and synthesis of thiol-terminated imidothioether oligomer as thermally latent hardener and modifier for high-performance epoxy/thiol thermosets

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第2期67卷 632-641页

作者： Xing liu Jianjun Zhou Shumei liu Jianqing Zhao School of Materials Science and Engineering South China University of TechnologyGuangzhou510640China Key Lab Guangdong High Property&Functional Polymer Materials Key Laboratory of Polymer Processing EngineeringMinistry of EducationGuangzhou510640China

Conventional base-catalyzed epoxy/aliphatic thiol systems have a poor storage stability,and are impossible to be one-pot systems.A widely accepted solution is to use the latent catalysts,which are usually insoluble anionic initiators sensitive to impurities and moisture,and have many limitations in practical *** this work,a soluble thiol-terminated imidothioether oligomer(TPI) was synthesized and used as a latent hardener and modifier to prepare one-pot epoxy/thiol systems without the latent *** latent behavior and curing mechanism of epoxy systems(EP/TPI series),consisted of bisphenol A diglycidyl ether(DGEBA),pentaerythritol tetrakis(mercaptoacetate)(PETMP) and TPI,were *** thiol exchange reaction between TPI and PETMP preceded the curing reaction of DGEBA,and produced aromatic thiols,which were unreactive at ambient conditions and reacted with DGEBA to form the thermosets at temperatures above 130 ℃.At the loading of 24.4 wt%TPI,the epoxy system(EP/TPI-3) had a shelf life of 13 days and was completely cured within 20 min at 180 ℃.Meanwhile,the catalyst-free curing process of EP/TPI-3 system was insensitive to impurities and ***,the thermal and mechanical properties of EP/TPI-3 thermoset were simultaneously improved,thereinto,the glass transition temperature,Young's modulus and ultimate tensile strength were increased by 16.7 ℃,12.9%,and 13.6%,respectively,compared with those of the commercial DGEBA/PETMP *** work shows that TPI has the potential to be a powerful alternative to commercial latent catalysts,and EP/TPI thermosets with high performance have broad application prospects.

关键词： thiol-terminated imidothioether oligomer epoxy systems thiol exchange reaction thermal latency high performance