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Science China(Information Sciences) 2022年第11期65卷 196-216页

作者： Gui-Hua ZHAO Shu-Jun LIU College of Science University of Shanghai for Science and Technology College of Mathematics Sichuan University

In this study, we investigate the stochastic finite-time stability theory and finite-time stabilization of stochastic time-varying nonlinear systems with Markovian switching in the sense of weak solutions. First,we present the stochastic finite-time stability theory under the framework of weak solutions: the existence of weak solutions and stochastic finite-time stability theorems for stochastic time-varying nonlinear systems with Markovian switching. Second, for a class of high-order stochastic nonlinear systems with Markovian switching, a finite-time stabilization controller is constructively designed, and the trivial weak solution of a closed-loop system is proven to be globally finite-time stable in probability. The effectiveness of the proposed finite-time control method is illustrated by a numerical example.

关键词： stochastic time-varying nonlinear systems Markovian switching weak solutions stochastic finite-time stability finite-time control

Numerical simulations for radon migration and exhalation behavior during measuring radon exhalation rate with closed-loop method

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Nuclear Science and Techniques 2024年第1期35卷 81-95页

作者： Ming Xia Yong-jun Ye shu-Yuan liu School of Resources Environment and Safety Engineering University of South ChinaHengyang 421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang 421001China

Accurate measurements of the radon exhalation rate help identify and evaluate radon risk regions in the environment.Among these measurement methods,the closed-loop method is frequently used.However,traditional experiments are insufficient or cannot analyze the radon migration and exhalation patterns at the gas–solid interface in the accumulation chamber.The CFD-based technique was applied to predict the radon concentration distribution in a limited space,allowing radon accumulation and exhalation inside the chamber intuitively and visually.In this study,three radon exhalation rates were defined,and two structural ventilation tubes were designed for the chamber.The consistency of the simulated results with the variation in the radon exhalation rate in a previous experiment or analytical solution was verified.The effects of the vent tube structure and flow rate on the radon uniformity in the chamber;permeability,insertion depth,and flow rate on the radon exhalation rate and the effective diffusion coefficient on back-diffusion were investigated.Based on the results,increasing the inser-tion depth from 1 to 5 cm decreased the effective decay constant by 19.55%,whereas the curve-fitted radon exhalation rate decreased(lower than the initial value)as the deviation from the initial value increased by approximately 7%.Increasing the effective diffusion coefficient from 2.77×10^(-7) to 7.77×10^(-6) m^(2) s^(-1) made the deviation expand from 2.14 to 15.96%.The conclusion is that an increased insertion depth helps reduce leakage in the chamber,subject to notable back-diffusion,and that the closed-loop method is reasonably used for porous media with a low effective diffusion coefficient in view of the back-diffusion effect.The CFD-based simulation is expected to provide guidance for the optimization of the radon exhalation rate measurement method and,thus,the accurate measurement of the radon exhalation rate.

关键词： Radon exhalation Numerical simulation Accumulation chamber

Tunable photocatalytic oxysulfonylation and chlorosulfonylation ofα-CF_(3) alkenes with sulfonyl chlorides

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Organic Chemistry Frontiers 2022年第3期9卷 709-714页

作者： Peng-Ju Xia Fu liu shu-Hui Li jun-An Xiao School of Chemistry and Pharmaceutical Sciences Guangxi Normal UniversityGuilin 541004P.R.China Guangxi Key Laboratory of Natural Polymer Chemistry and Physics Nanning Normal UniversityNanning530001P.R.China

Tunable photoredox-catalyzed chlorosulfonylation and oxysulfonylation ofα-trifluoromethylstyrenes with sulfonyl chloride were facilely achieved by simply manipulating the photocatalyst and solvent.This strategy makes full use of the structural features of sulfonyl chloride to afford diverse bifunctional products ofα-trifluoromethylstyrenes in up to 95%yield with excellent functional group tolerance.

关键词： sulfonyl styrene simply

Numerical Simulation on Radon Retardation Behavior of Covering Floats in Radon-Containing Water

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Biomedical and Environmental Sciences 2024年第4期37卷 406-417页

作者： liu shu Yuan ZHANG Li YE Yong jun DING Ku Ke National Institute for Radiological Protection Chinese Center for Disease Control and PreventionBeijing 100088China Office for Public Health Management Chinese Center for Disease Control and PreventionBeijing 102206China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang 421001HunanChina

Objective This study aimed to efficiently reduce the release of radon from water bodies to protect the environment.Methods Based on the sizes of the experimental setup and modular float,computational fluid dynamics(CFD)was used to assess the impact of the area coverage rate,immersion depth,diffusion coefficient,and radon transfer velocity at the gas–liquid interface on radon migration and exhalation of radon-containing water.Based on the numerical simulation results,an estimation model for the radon retardation rate was constructed.The effectiveness of the CFD simulation was evaluated by comparing the experimental and simulated variation values of the radon retardation rate with the coverage area rates.Results The effect of radon transfer velocity on radon retardation in water bodies was minor and insignificant according to the appropriate value;therefore,an estimation model of the radon retardation rate of the coverage of a radon-containing water body was constructed using the synergistic impacts of three factors:area coverage rate,immersion depth,and diffusion coefficient.The deviation between the experimental and simulated results was<4.3%.Conclusion Based on the numerical simulation conditions,an estimation model of the radon retardation rate of covering floats in water bodies under the synergistic effect of multiple factors was obtained,which provides a reference for designing covering floats for radon retardation in radoncontaining water.

关键词： Radon-containing water Radon retardation rate CFD Coverage experiment Optimized design

Antiplatelet and myocardial protective effect of Shexiang Tongxin Dropping Pill in patients undergoing percutaneous coronary intervention:A randomized controlled trial

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Journal of Integrative Medicine 2022年第2期20卷 126-134页

作者： Yan-jun Lin Kun-li Jiao Bo liu Lu Fang shu Meng Department of Cardiology Xinhua HospitalShanghai Jiaotong University School of MedicineShanghai 200092China Haematopoiesis and Leukocyte Biology Laboratory Baker Heart and Diabetes Research InstituteMelbourneVIC 3004Australia

Background:High on-clopidogrel platelet reactivity could be partially explained by loss-of-function alleles of CYP2 C19,the enzyme that converts clopidogrel into its active form.Shexiang Tongxin Dropping Pill(STDP)is a traditional Chinese medicine to treat angina pectoris.STDP has been shown to improve blood flow in patients with slow coronary flow and attenuate atherosclerosis in apolipoprotein E-deficient mice.However,whether STDP can affect platelet function remains unknown.Objective:The purpose of this study is to examine the potential effects of STDP on platelet function in patients undergoing percutaneous coronary intervention(PCI)for unstable angina.The interaction between the effects of STDP with polymorphisms of CYP2 C19 was also investigated.Design,participants and intervention:This was a single-center,randomized controlled trial in patients undergoing elective PCI for unstable angina.Eligible subjects were randomized to receive STDP(210 mg per day)plus dual antiplatelet therapy(DAPT)with clopidogrel and aspirin or DAPT alone.Main outcome measures:The primary outcome was platelet function,reflected by adenosine diphosphate(ADP)-induced platelet aggregation and platelet microparticles(PMPs).The secondary outcomes were major adverse cardiovascular events(MACEs)including recurrent ischemia or myocardial infarction,repeat PCI and cardiac death;blood biomarkers for myocardial injury including creatine kinase-MB isoenzyme(CK-MB)and high-sensitive troponin I(hs Tn I);and biomarkers for inflammation including intercellular cell adhesion molecule-1(ICAM-1),vascular cell adhesion molecule-1(VCAM-1),monocyte chemoattractant protein-1(MCP-1)and galectin-3.Results:A total of 118 subjects(mean age:[66.8±8.9]years;male:59.8%)were included into analysis:58 in the control group and 60 in the STDP group.CYP2 C19 genotype distribution was comparable between the 2 groups.In comparison to the control group,the STDP group had significantly lower CKMB(P0.05)at 24 h after PCI,lower ICAM-1,VCAM-1,MCP

关键词： Shexiang Tongxin Dropping Pill Traditional Chinese medicine Dual antiplatelet therapy CYP2C19 gene polymorphism Platelet reactivity

Controllable image generation based on causal representation learning

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Frontiers of Information Technology & Electronic Engineering 2024年第1期25卷 135-148页

作者： Shanshan HUANG Yuanhao WANG Zhili GONG jun LIAO shu WANG Li liu School of Big Data and Software Engineering Chongqing UniversityChongqing 401331China School of Materials and Energy Southwest UniversityChongqing 400715China

Artificial intelligence generated content(AIGC)has emerged as an indispensable tool for producing large-scale content in various forms,such as images,thanks to the significant role that AI plays in imitation and production.However,interpretability and controllability remain challenges.Existing AI methods often face challenges in producing images that are both flexible and controllable while considering causal relationships within the images.To address this issue,we have developed a novel method for causal controllable image generation(CCIG)that combines causal representation learning with bi-directional generative adversarial networks(GANs).This approach enables humans to control image attributes while considering the rationality and interpretability of the generated images and also allows for the generation of counterfactual images.The key of our approach,CCIG,lies in the use of a causal structure learning module to learn the causal relationships between image attributes and joint optimization with the encoder,generator,and joint discriminator in the image generation module.By doing so,we can learn causal representations in image’s latent space and use causal intervention operations to control image generation.We conduct extensive experiments on a real-world dataset,CelebA.The experimental results illustrate the effectiveness of CCIG.

关键词： Image generation Controllable image editing Causal structure learning Causal representation learning

Dual-steering mode based on direct yaw moment control for multi-wheel hub motor driven vehicles:Theoretical design and experimental assessment

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Defence Technology（防务技术） 2022年第1期18卷 49-61页

作者： Zheng Zhang Xiao-jun Ma Chun-guang liu shu-guang Wei Department of Weapons and Control Engineering Army Academy of Armored ForcesBeijing100072China

One of the main challenges for multi-wheel hub motor driven vehicles is the coordination of individual drivetrains to improve mobility and stability in the steering process.This paper proposes a dual-steering mode based on direct yaw moment control for enhancing vehicle steering ability in complex environ ments.The control system is designed as a hierarchical structure,with a yaw moment decision layer and a driving force distribution layer.In the higher-level layer,the objective optimization function is con-structed to obtain the slip steering ratio,which represents the degree of vehicle slip steering in the dual-steering mode.Ayaw moment controller using active disturbance rejection control theory is designed for continuous yaw rate control.When the actual yaw rate of the vehicle deviates from the reference yaw rate obtained by the vehicle reference model and the slip steering ratio,the yaw moment controller isactuated to determine the yaw moment demand for vehicle steering.In the lower-level layer,there is a torque distribution controller based on distribution rules,which meets the requirement of yaw moment demand without affecting the total longitudinal driving force of the vehicle.For verifying the validity and feasibility of the dual-steering mode,simulations were conducted on the hardware-in-loop real-time simulation platfomm.Additionally,corresponding real vehicle tests were carried out on an eight-wheel prototype vehicle.Test results were generally consistent with the simulation results,thereby demon-strating that the proposed dual-steering mode reduces steering radius and enhances the steering per-formance of the vehicle.

关键词： Multi-wheel hub motor driven vehide Dual-steering mode Direct ya w moment control Real-time simulation

Hydrodynamic Response and Power Performance of A Heave and Pitch Buoy Wave Energy Converter Under Bimodal Ochi-Hubble Wave Spectrum

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China Ocean Engineering 2022年第1期36卷 28-37页

作者： HUANG shu-ting liu Yan-jun XUE Gang XUE Yi-fan Institute of Marine Science and Technology Shandong UniversityQingdao 266237China School of Mechanical Engineering Shandong UniversityJinan 250061China

In coastal sea areas with the bimodal Ochi-Hubble wave spectrum, such as parts of the China Sea and Indian Ocean,wave energy is the superposition of wind wave and swell. Traditional heaving buoy wave energy converters developed with narrowband wave spectrums suffer from big energy loss in these areas, leading to lower power absorption efficiency and higher generating costs. In contrast, multi-freedom buoy has different resonant frequencies and maximal power capture wave frequencies in different degrees of freedom(DOFs). Therefore, this study proposed using two DOFs to capture the energy of wind wave and swell correspondingly. A heave and pitch buoy model was established by potential flow theory and validated by experimental data. Coupling effect on the motion and power absorption, power capture frequency distribution and power absorption with different linear power takeoff system damping coefficients were analyzed to reveal the hydrodynamic response and the power performance of the two DOFs. The results indicate that by using heave and pitch DOFs, the wave energy components of wind wave and swell were captured in a targeted manner. It demonstrates that the 2-DOF buoy is an effective tool to avoid the energy loss and realize the efficient power absorption in coastal sea areas with bimodal Ochi-Hubble waves.

关键词： wave energy power performance oscillating buoy multi degrees of freedom Ochi−Hubble spectrum

Optimal allocation method of energy storage for integrated renewable generation plants based on power market simulation

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Energy Storage and Saving 2023年第3期2卷 540-547页

作者： Dazheng liu Fei Zhao shu Wang Yongmei Cui jun shu CHN ENERGY Technology&Economics Research Institute Beijing102211China China Electric Power Research Institute Beijing100192China School of Electrical&Electronic Engineering North China Electric Power UniversityBeijing102206China School of New Energy Harbin Institute of Technology WeihaiWeihaiShandong264209China

This study designs and proposes a method for evaluating the configuration of energy storage for integrated re-newable generation plants in the power spot market,which adopts a two-level optimization model of“system simulation+plant optimization”.The first step is“system simulation”which is using the power market simu-lation model to obtain the initial nodal marginal price and curtailment of the integrated renewable generation plant.The second step is“plant optimization”which is using the operation optimization model of the integrated renewable generation plant to optimize the charge-discharge operation of energy storage.In the third step,“sys-tem simulation”is conducted again,and the combined power of renewable and energy storage inside the plant is brought into the system model and simulated again for 8,760 h of power market year-round to quantify and compare the power generation and revenue of the integrated renewable generation plant after applying energy storage.In the case analysis of the provincial power spot market,an empirical analysis of a 1 GW wind-solar-storage integrated generation plant was conducted.The results show that the economic benefit of energy storage is approximately proportional to its capacity and that there is a slowdown in the growth of economic benefits when the capacity is too large.In the case that the investment benefit of energy storage only considers the in-come of electric energy-related incomes and does not consider the income of capacity mechanism and auxiliary services,the income of energy storage cannot fulfill the economic requirements of energy storage investment.

关键词： Integrated renewable generation plant Energy storage Optimal allocation Two-level optimization model Power spot market Power market simulation

Directly imaging of the atomic structure of luminescent centers in CaYAlO_(4):Ce^(3+)

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Nano Research 2023年第2期16卷 3004-3009页

作者： Yalong Zhai Xuewei Yang shu-Na Zhao Pei liu jun Lin Yang Zhang School of Materials Science and Engineering Center of Advanced Analysis&Gene SequencingZhengzhou UniversityZhengzhou 450001China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China DTU Nanolab.Technical University of Denmark Fysikvej2800 Kgs.LyngbyDenmark Green Catalysis Center and College of Chemistry Zhengzhou UniversityZhengzhou 450001China

Lanthanides(Ln^(3+))doped luminescent materials play critical roles in lighting and display techniques.While increasing experimental and theoretical research have been carried out on aluminate-based phosphors for white light-emitting diodes(WLEDs)over the past decades,most investigation was mainly focused on their luminescent properties;therefore,the local structure of the light emission center remains unclear.Especially,doping-induced local composition and structure modification around the luminescent centers have yet to be unveiled.In this study,we use advanced electron microscopy techniques including electron diffraction(ED),high-resolution transmission electron microscopy(HRTEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM),in combination with energy dispersive X-ray spectroscopy(EDX)and electron energy loss spectroscopy(EELS),to reveal atomically resolved crystalline and chemical structure of Ce^(3+)doped CaYAlO4.The microscopic results prove substantial microstructural and compositional inhomogeneities in Ce^(3+)doped CaYAlO_(4),especially the appearance of Ce dopant clustering and Ce^(3+)/Ce^(4+)valence variation.Our research provides a new understanding the structure of Ln^(3+)doped luminescent materials and will facilitate the materials design for next-generation WLEDs luminescent materials.

关键词： luminescent white light-emitting diodes(WLEDs) rare earth element atomic structure chemical structure